阅读说明：本技术 二维压力伺服变量泵 (Two-dimensional pressure servo variable pump ) 是由 阮健 郑飞侠 王熙 宋占凯 赵建涛 吴圣 孟彬 于 2019-04-30 设计创作，主要内容包括：二维压力伺服变量泵,包括前端盖、泵体、后端盖、双联柱塞泵、压力伺服变量机构；压力伺服变量机构包括二维脉宽调制机构、二维压力伺服阀；双联柱塞泵包括二维脉宽调制机构和二维压力伺服阀；前端盖内设有主动齿轮、从动齿轮、深沟球轴承,主动齿轮与电机联轴器固连,从动齿轮与二维脉宽调制机构固连；双联柱塞泵包括上联泵芯与下联泵芯；上联泵芯的上联缸体左右两端均固连具有相同等加等减速曲面轨道的上联左导轨、上联右导轨,上联左导轨与上联右导轨的相位差90度；二维脉宽调制机构的传动轴拨叉与滚轮组件配合通过滚轮轴拨动第一阀芯,第一阀芯在第一阀套内做周向转动的同时轴向滑动,第一阀芯转动与轴向滑动相对独立。(The two-dimensional pressure servo variable pump comprises a front end cover, a pump body, a rear end cover, a duplex plunger pump and a pressure servo variable mechanism; the pressure servo variable mechanism comprises a two-dimensional pulse width modulation mechanism and a two-dimensional pressure servo valve; the duplex plunger pump comprises a two-dimensional pulse width modulation mechanism and a two-dimensional pressure servo valve; a driving gear, a driven gear and a deep groove ball bearing are arranged in the front end cover, the driving gear is fixedly connected with a motor coupler, and the driven gear is fixedly connected with a two-dimensional pulse width modulation mechanism; the duplex plunger pump comprises an upper pump core and a lower pump core; the left end and the right end of an upper cylinder body of the upper pump core are fixedly connected with an upper left guide rail and an upper right guide rail which are provided with the same equal deceleration curved surface track, and the phase difference between the upper left guide rail and the upper right guide rail is 90 degrees; a transmission shaft shifting fork of the two-dimensional pulse width modulation mechanism is matched with the roller assembly to shift the first valve core through the roller shaft, the first valve core rotates in the circumferential direction in the first valve sleeve and slides in the axial direction at the same time, and the rotation and the axial sliding of the first valve core are relatively independent.)

1. Two-dimensional pressure servo variable pump, its characterized in that: the pump comprises a front end cover, a pump body, a rear end cover, a duplex plunger pump and a pressure servo variable mechanism; the pressure servo variable mechanism comprises a two-dimensional pulse width modulation mechanism and a two-dimensional pressure servo valve;

the front end cover is fixedly connected with the pump body through a screw; the rear end cover is fixedly connected with the pump body through a screw; the duplex plunger pump is fixed in the pump body; the two-dimensional pulse width modulation mechanism and the two-dimensional pressure servo valve are fixedly connected with the pump body through screws;

a driving gear, a driven gear and a deep groove ball bearing are arranged in the front end cover, the driving gear is fixedly connected with a motor coupler, and the driven gear is fixedly connected with a two-dimensional pulse width modulation mechanism;

the pump body is provided with an oil inlet, an oil outlet, a first through hole, a second through hole and a third blind hole; the oil outlet is arranged at the top of the pump body, the first through hole is arranged at the lower part of the pump body, is communicated with the oil inlet and is provided with a duplex plunger pump; the second through hole is arranged at the upper part of the pump body and is provided with a two-dimensional pulse width modulation mechanism; the third blind hole is arranged at the upper part of the pump body and is provided with a two-dimensional pressure servo valve;

The duplex plunger pump comprises an upper pump core and a lower pump core, wherein the upper pump core is close to the front end cover, and the lower pump core is close to the rear end cover;

the upper pump core comprises an upper cylinder body, an upper plunger, an upper left end structural shaft, an upper right end structural shaft, a first concentric ring, a second concentric ring, an upper left guide rail, an upper right guide rail and a positioning pin; the upper plunger is arranged in the upper cylinder body, the left end and the right end of the upper plunger are fixedly connected with an upper left end structural shaft and an upper right end structural shaft respectively through positioning pins, and the left side and the right side of the upper plunger are respectively provided with a first concentric ring and a second concentric ring; the left end and the right end of the upper cylinder body are fixedly connected with an upper left guide rail and an upper right guide rail which are provided with equal deceleration curved surface tracks, the circumferences of the equal deceleration curved surface tracks of the upper left guide rail and the upper right guide rail are mutually staggered by 90 degrees, namely, the highest point and the lowest point of the equal deceleration curved surface tracks of the upper left guide rail and the equal deceleration curved surface tracks of the upper right guide rail correspond to the lowest point and the highest point of the equal deceleration curved surface tracks of the upper right guide rail;

the middle of the upper plunger is provided with a shoulder, the surface of the upper plunger is provided with four rectangular distribution grooves which are uniformly distributed, and the notch positions of the four rectangular distribution grooves are arranged in a staggered way;

Four flow distribution windows are uniformly distributed on the upper cylinder body and respectively comprise two oil inlets and two oil outlets, the oil inlets and the oil outlets are alternately arranged, low-pressure oil is introduced into the oil inlets, high-pressure oil is introduced into the oil outlets, and the oil inlets and the oil outlets are not communicated with each other; two sides of the oil outlet are sealed by sealing rings; the flow distribution window is arranged corresponding to the flow distribution groove on the upper coupling plunger;

the upper-connected left end structural shaft comprises a first structural shaft main body, a first large roller, a second large roller, a first small roller pair and a second small roller pair; the second big roller wheel and the first big roller wheel have the same structure to form a first big roller wheel group; the second small roller pair and the first small roller pair have the same structure to form a first small roller group; the first large roller comprises a conical roller bearing sleeve and a deep groove ball bearing, the outer part of the bearing sleeve is a conical surface, the inner part of the bearing sleeve is a round hole, and an inner hole of the bearing sleeve is sleeved on the outer circle of the deep groove ball bearing and fixedly connected with the outer circle of the deep groove ball bearing; the first small roller pair comprises a large cylindrical roller and a small cylindrical roller, the large cylindrical roller comprises a cylindrical bearing sleeve and a deep groove ball bearing, the outer part of the bearing sleeve is a cylinder, the inner part of the bearing sleeve is a round hole, and the inner hole of the bearing sleeve is sleeved on the outer circle of the deep groove ball bearing and fixedly connected with the outer circle of the deep groove ball bearing; the small cylindrical roller comprises a cylindrical roller sleeve and a copper sleeve, the outer part of the roller sleeve is cylindrical, the inner part of the roller sleeve is a round hole, and an inner hole of the roller sleeve is sleeved on the outer circle of the copper sleeve and fixedly connected with the outer circle of the copper sleeve; the first large roller and the second large roller are fixedly connected to two ends of the first structural shaft main body through nuts and are arranged in axial symmetry; the first small roller pair and the second small roller pair are fixedly connected to two ends of the first structural shaft main body by positioning pins and are arranged in central symmetry;

The upper-connected right-end structural shaft is completely identical to the left-end structural shaft in structure;

the rolling surfaces of the large roller groups of the upper left end structural shaft and the upper right end structural shaft are respectively matched with the corresponding upper left guide rail and the upper right guide rail, and the rolling surface of the small roller group of the upper left end structural shaft is matched with a track carried by the motor coupler; the rolling surface of the small roller set of the upper-coupling right-end structural shaft is matched with a track carried by a shifting fork structure of the third structural shaft main body;

the first concentric ring, the upper plunger piston and the upper cylinder body jointly enclose a space to form a first left chamber, the second concentric ring, the upper plunger piston and the upper cylinder body jointly enclose a space to form a first right chamber, and the volumes of the first left chamber and the first right chamber are changed in a staggered manner along with the reciprocating motion of the plunger piston;

the lower pump core comprises a lower cylinder body, a lower plunger, a lower left end structure shaft, a lower right end structure shaft, a third concentric ring, a fourth concentric ring, a lower left guide rail, a lower right guide rail and a positioning pin; the lower-link plunger is arranged in the lower-link cylinder body, the left end and the right end of the lower-link plunger are fixedly connected with a lower-link left end structural shaft and a lower-link right end structural shaft respectively through positioning pins, and the left side and the right side of the lower-link plunger are respectively provided with a third concentric ring and a fourth concentric ring; the left end and the right end of the lower cylinder body are fixedly connected with a lower left guide rail and a lower right guide rail which are provided with the same equal-speed-reducing curved surface track; the arrangement mode of the lower left guide rail and the lower right guide rail is the same as that of the upper left guide rail and the upper right guide rail;

The lower cylinder body and the upper cylinder body are completely identical in structure;

the lower-linked plunger piston and the upper-linked plunger piston are completely identical in structure, and the upper-linked plunger piston and the lower-linked plunger piston are concentrically arranged;

the lower-connection left-end structural shaft comprises a third structural shaft main body and a third large roller group; the third structural shaft main body is provided with a shifting fork structure and is matched and connected with a small roller set of the upper-coupling right-end structural shaft, so that the upper-coupling pump core and the lower-coupling pump core are staggered by 45 degrees in space; the right structural shaft of the lower coupling comprises a fourth structural shaft main body and a fourth big roller group; the third large roller group and the fourth large roller group have the same structure as the first large roller group of the upper-linked left-end structural shaft, and the placement modes are also the same; the rolling surfaces of a third large roller group and a fourth large roller group of the lower-joint left-end structural shaft and the lower-joint right-end structural shaft are respectively matched with a lower-joint left guide rail and a lower-joint right guide rail on the lower-joint cylinder body;

the space enclosed by the third concentric ring, the lower-connected plunger piston and the lower-connected cylinder body forms a second left chamber, the space enclosed by the fourth concentric ring, the lower-connected plunger piston and the lower-connected cylinder body forms a second right chamber, and the volumes of the second left chamber and the second right chamber are changed in a staggered manner along with the reciprocating motion of the plunger piston;

the two-dimensional pulse width modulation mechanism comprises a transmission shaft, a zero position spring, a roller shaft, a left roller assembly, a right roller assembly, a front concentric ring, a first valve core, a first valve sleeve, a rear concentric ring and a first valve core plug; the transmission shaft shifting fork is matched with the roller component to shift the first valve core through the roller shaft, so that the first valve core rotates in the circumferential direction and slides axially in the first valve sleeve, the rotation and the axial sliding of the first valve core are relatively independent, the front concentric ring and the rear concentric ring are fixedly connected to two ends of the first valve sleeve respectively, and the zero-position spring is arranged between the first valve core and the transmission shaft and is in a compressed state;

One end of the transmission shaft is a cylindrical end and is connected with the transmission mechanism; the other end of the transmission shaft is in a door frame shape and is connected with two U-shaped shifting forks, and the shifting fork surfaces are axial incomplete cylindrical surface tracks and are matched with the left roller assembly and the right roller assembly to enable the first valve core to axially slide while circumferentially rotating; the axial middle end surface of the transmission shaft is provided with a circular groove for fixing a zero spring;

two flat end surfaces of the zero-position spring are respectively fixed at the circular groove of the transmission shaft and the stepped shaft at the left end of the first valve core, the zero-position spring is in a compressed state in the initial and working processes, the first valve core is ensured to be at the rightmost end in the initial state, and the zero position of the first valve core is kept;

the roller shaft is a stepped cylindrical shaft, the middle of the stepped cylindrical shaft is provided with a shoulder, and the diameter of the middle cylinder is larger than that of the cylinders at the two sides; the middle shoulder shaft is inserted into and fixedly connected with the cylindrical hole at the left end of the first valve core, and the shafts at the two ends are respectively inserted into and fixedly connected with the central circular holes of the left roller assembly and the right roller assembly;

the right roller assembly and the left roller assembly are completely the same in structure and comprise a bearing sleeve and a deep groove ball bearing, the outer part of the bearing sleeve is a spherical surface, the inner part of the bearing sleeve is a round hole, the two ends of the bearing sleeve are flat end surfaces, an inner hole of the bearing sleeve is sleeved on the outer circle of the deep groove ball bearing and fixedly connected with the outer circle of the deep groove ball bearing, and the spherical surface of the bearing sleeve is matched with the;

The front concentric ring is annular, two end faces are planes, the excircle of the front concentric ring is fixedly connected with the first valve sleeve, and the inner hole is sleeved on the left end shaft of the first valve core;

the rear concentric ring is annular, two end faces are planes, an inner hole is provided with a stepped hole to provide an avoidance space for a second circular through hole of the first valve core, the outer circle of the rear concentric ring is fixedly connected with the first valve sleeve, and the inner hole is sleeved on a shaft at the right end of the first valve core;

the inner hole of the first valve sleeve is a central through hole and is matched with the first valve core, and a front stepped hole and a rear stepped hole are respectively arranged at two ends and are respectively fixedly connected with a front concentric ring and a rear concentric ring; the excircle of the first valve sleeve is provided with four annular grooves, a control oil groove, an oil outlet groove, an oil inlet groove and an oil return groove are respectively arranged from left to right, the control oil groove is uniformly provided with a plurality of same radial control oil holes, the oil outlet groove is uniformly provided with a plurality of same radial oil outlet holes, the oil inlet groove is uniformly provided with a plurality of same radial rhombic flow distribution windows, the vertexes of the rhombic flow distribution windows are positioned in the same plane, the plane is vertical to the axis of the first valve core, and the oil return groove is uniformly provided with a plurality of same radial oil return holes;

the leftmost end of the first valve core is provided with a step shaft for mounting a zero position spring, and the right side of the step shaft is provided with a roller shaft circular through hole which is fixedly connected with the roller shaft and used for transmitting torque to the first valve core to enable the first valve core to rotate; the first valve core is provided with three shoulders, a first shoulder, a second shoulder and a third shoulder are sequentially arranged from left to right, a first circular through hole is radially arranged on a first valve core shaft between the first shoulder and the second shoulder, a second circular through hole is radially arranged on the first valve core shaft close to the right end face of the third shoulder, a central flow passage is axially arranged in the center of the first valve core, a central flow passage port is plugged by a first valve core in a plugging manner, and the first circular through hole is communicated with the second circular through hole through the first valve core central flow passage; two rows of staggered triangular flow distribution windows, namely a left triangular flow distribution window and a right triangular flow distribution window, are formed in the second shoulder of the first valve core, the vertex of each triangular flow distribution window is in the same plane, and the plane is perpendicular to the axis of the first valve core;

The spherical surface of the excircle of the bearing sleeve is in clearance fit with the U-shaped shifting fork of the transmission shaft, and the spherical surface of the excircle of the bearing sleeve is in unilateral contact when stressed, so that positive and negative rotation can be realized;

the outer circles of the front concentric ring and the rear concentric ring are fixedly connected in a front stepped hole and a rear stepped hole of two end faces of the first valve sleeve respectively, an inner hole of the front concentric ring is sleeved on a left end shaft of the first valve core and is sealed by a gap, and an inner hole of the rear concentric ring is sleeved on a right end shaft of the first valve core and is sealed by a gap;

the first valve core is rotatably arranged in the first valve sleeve, the front concentric ring and a first shoulder of the first valve core seal an inner cavity of the first valve sleeve to form a control cavity, the control cavity is communicated with the control oil groove through the control oil hole, and the control oil groove is communicated with control pressure oil; the first shoulder and the second shoulder of the first valve core seal the inner cavity of the first valve sleeve to form a high-pressure cavity, the high-pressure cavity is communicated with the oil outlet groove through the oil outlet hole and is communicated with the oil inlet groove through the rhombic flow distribution window, high-pressure oil of the hydraulic pump is introduced into the oil inlet groove, and a system oil way is introduced into the oil outlet groove; the second shoulder and the third shoulder of the first valve core seal the inner cavity of the first valve sleeve to form a low-pressure cavity, the low-pressure cavity is communicated with the oil return groove through the oil return hole, and the oil return groove is communicated with a low-pressure oil tank; the third shoulder of the first valve core and the rear concentric ring seal the inner cavity of the first valve sleeve to form a feedback cavity, the feedback cavity is communicated with the high-pressure cavity through the first circular through hole, the central flow channel and the second circular through hole of the first valve core, and the pressures of the two cavities are the same; the first valve sleeve controls the oil groove, the oil outlet groove, the oil inlet groove and the oil return groove to be not communicated with each other outside the first valve sleeve; two rows of staggered triangular flow distribution windows are formed in the second shoulder of the first valve core and are respectively a left triangular flow distribution window and a right triangular flow distribution window, the rhombic flow distribution window of the first valve sleeve is positioned on the motion track of the second shoulder of the first valve core, and the first valve core axially slides under the action of hydraulic pressure while rotating at a constant speed in the first valve sleeve, so that the ratio of the flow distribution time of the left triangular flow distribution window and the right triangular flow distribution window of the first valve core to the rhombic flow distribution time of the first valve sleeve is changed, and the flow of outlet oil is changed to realize flow distribution;

The two-dimensional pressure servo valve consists of a valve body module, a displacement sensor module and an electro-mechanical converter module, wherein the displacement sensor module is matched with the valve body module, and the electro-mechanical converter module is matched with the valve body module; the displacement sensor module monitors the displacement of the 2D piston in the valve body module in real time and forms closed-loop feedback with the torque motor electric signal of the electro-mechanical converter module;

the valve body module comprises a second valve core, a second valve core shell, a 2D piston, a left gasket, a right gasket, a concentric ring, a pressure regulating spring, a second valve sleeve, a valve sleeve plug and a positioning pin; the second valve core is arranged in an inner hole of a second valve core shell, the 2D piston is arranged on the right side of the second valve sleeve, the valve sleeve plug is fixedly connected to the left end part of the second valve sleeve through a positioning pin, and the second valve core shell is positioned through the valve sleeve plug and fixed on the left side of the second valve sleeve; the left gasket is connected to the right end of the second valve core, the right gasket is connected to the left end of the 2D piston, a pressure regulating spring is connected between the left gasket and the right gasket, and a concentric ring is arranged on the right side of the 2D piston;

the second valve sleeve is provided with three annular grooves which are respectively an oil inlet groove, an oil outlet groove and an oil return groove from left to right, the oil inlet groove is uniformly provided with a plurality of same radial oil inlet holes, the oil outlet groove is uniformly provided with a plurality of same radial oil outlet holes, and the oil return groove is uniformly provided with a plurality of same radial oil return holes; a pair of damping chutes matched with the high-low pressure grooves on the 2D piston shoulder are formed in the inner hole wall on the right side of the second valve sleeve; the second valve sleeve is provided with O-shaped sealing rings on two sides of each oil port, so that the local sealing of the servo valve is ensured;

The 2D piston is arranged in the second valve sleeve, and two movement directions of circumferential rotation and axial sliding are arranged in the second valve sleeve; the left end of the 2D piston is provided with a shoulder, the shoulder is provided with a pair of high-pressure grooves and a pair of low-pressure grooves in a matched manner, the shoulder is matched with a pair of damping chutes formed in the inner wall of a second valve sleeve, the pair of high-pressure grooves are communicated with an oil inlet hole, the pair of low-pressure grooves are communicated with an oil return hole, the shoulder and a concentric ring of the 2D piston are sealed with the second valve sleeve to form a left sensitive cavity and a right sensitive cavity, the pair of high-pressure grooves and the pair of low-pressure grooves on the shoulder of the 2D piston are intersected with the pair of damping chutes to form four tiny opening areas which are connected in series to form a hydraulic resistance half bridge, the pressure change of the left sensitive cavity is controlled by the hydraulic resistance half bridge, the right sensitive cavity is communicated with the oil inlet hole;

the second valve core shell is uniformly provided with 4 same radial through holes on a left end shoulder, and the through holes are communicated with the oil inlet; 4 same radial through holes are uniformly formed in the annular groove in the right side of the second valve core shell and are communicated with the oil outlet; the second valve core shell is matched with the valve sleeve plug to form a control cavity;

the left side and the right side of the second valve core are respectively provided with a shoulder which is matched with the shell of the second valve core, and the opening degrees of the oil inlet and the oil return port are changed when the second valve core moves axially; the left end face of the second valve core is designed into a disc-shaped structure, when the second valve core moves left and right, an extrusion oil film is formed between the disc-shaped structure of the second valve core and a closed cavity formed by the second valve core shell and the valve sleeve plug, and the extrusion oil film has the functions of introducing an extrusion oil film damping coefficient, increasing the viscous damping of a system and improving the damping ratio to enable the system to be more stable; the second valve core is internally provided with a central flow passage which is connected with a through hole at the right side of the second valve core and is communicated with the control cavity;

The electric-mechanical converter module comprises a torque motor and a power supply module, wherein the torque motor comprises a shell, an armature, a permanent magnet, a magnetizer, a clamping piece, a motor outer cover, a coil, a spring rod, a spring seat, a limiting rod and a connecting plate; the electro-mechanical converter module is connected with the valve body through a connecting plate; the two-dimensional pressure servo valve adopts a dry torque motor, so O-shaped sealing rings are also arranged on a motor outer cover and a connecting plate, and an output part is sealed to prevent oil from entering a space around the armature, the coil and the permanent magnet;

the electro-mechanical converter module comprises a magnetic circuit part, a transmission part and a motor housing; the connecting plate is connected with the motor outer cover through screws; the magnetic circuit part consists of 2 coils, 2 magnetizers, 1 armature and 2 permanent magnets; when the coil is not electrified, the armature keeps balance; when the coil is electrified, a magnetic path is generated, the balance state before damage is caused, and the armature deflects; the transmission part comprises a spring, a spring seat, a spring rod, a limiting rod and a motor pin; (ii) a When the armature deflects, the 2D piston and the spring rod are driven to rotate; one end of the spring is connected with the spring rod, and the other end of the spring is connected with the spring seat fixedly connected on the shell;

The displacement sensor module comprises an LVDT connecting rod and an LVDT sensor consisting of an iron core and a coil framework, and the LVDT sensor is fixed on the shell; the spring rod is vertically connected with the LVDT connecting rod; the LVDT connecting rod is connected with the iron core, the iron core is in clearance fit with the LVDT sensor, and the inner hole of the LVDT sensor moves directly; the LVDT sensor is connected with the 2D piston of the valve body module through a threaded connecting rod.

2. A two-dimensional pressure servo variable displacement pump as claimed in claim 1, wherein: the LVDT sensor is matched with the shell and the arc of the clamping piece, and the clamping piece is pressed tightly by the LVDT sensor through the screw, so that the LVDT sensor is fixed.

Technical Field

The invention relates to a pressure servo variable pump, in particular to a pressure adjustable constant-pressure servo variable pump, belonging to a hydraulic pump and a hydraulic motor in the field of fluid transmission and control.

Background

In the working process of the plunger pump, the plunger reciprocates in the cylinder body, so that the sealed working volume is changed, and the oil suction and discharge processes are completed. Each plunger cavity of the axial plunger pump is periodically switched back and forth between the oil suction port and the oil discharge port, and the switching process of the oil ports needs to be realized through a flow distribution mechanism of the pump.

The axial plunger pump mainly has two flow distribution modes of valve flow distribution and end face flow distribution. The valve flow distribution mainly realizes flow distribution by a one-way valve, but the one-way valve has certain opening pressure and certain hysteresis in response. The end face flow distribution requires that a cylinder body of the pump rotates to enable a plunger cavity to be communicated with an oil suction and discharge window on a flow distribution plate alternately for oil suction and discharge. The plunger pump cylinder body has a plurality of plunger holes, and the cylinder body diameter is great, and high pressure, high rotational speed need higher design requirement to this pair of key friction of cylinder body and valve plate, increase the design degree of difficulty. The inclination angle of the swash plate of the axial piston pump is generally required to be within 20 degrees, so that the range of flow distribution is limited.

The traditional variable displacement actuator of the servo pump mostly realizes variable displacement by controlling a hydraulic cylinder by a servo valve to drive a variable displacement mechanism of the pump. The working oil of the variable mechanism is directly provided by the system or provided by a small pump which is coaxial with the variable pump. The mode is mature in technology and good in response performance, but the additional hydraulic actuating mechanism is complex in structure, and the failure rate of the system is increased.

The existing two-dimensional pumps all adopt valve banks such as two-dimensional unloading valves and two-dimensional pressure stabilizing valves to realize the regulation of pressure and flow, and have more parts, more control and regulation positions and larger pressure flow pulsation.

Compared with a common plunger pump, the plunger pump has the advantages of simple flow distribution process and wide flow distribution range; compared with a common servo pump, the pressure-flow distribution of the system is realized through the pressure servo variable mechanism, the constant and adjustable system pressure is realized, a servo motor or a complex hydraulic actuating mechanism is not needed, the structure is novel and compact, the adjusting range is wide, continuous adjustment can be realized, the sensitivity is high, and the response speed is high.

Disclosure of Invention

The invention provides a two-dimensional pressure servo variable pump which has the advantages of novel and compact structure, small volume, light weight, adjustable pressure, high pressure sensitivity, high response speed and the like, and aims to overcome the defects that the traditional plunger pump flow distribution mode is slow in response speed, complex in structure and small in adjustment range, a hydraulic actuating mechanism used by a traditional servo pump is complex, a two-dimensional servo pump flow distribution structure needs more parts, the control adjustment position is more, pressure pulsation is larger and the like.

The technical scheme adopted by the invention is as follows:

two-dimensional pressure servo variable pump, its characterized in that: the double-plunger pump comprises a front end cover, a pump body, a rear end cover, a double-plunger pump and a pressure servo variable mechanism. The pressure servo variable mechanism comprises a two-dimensional pulse width modulation mechanism and a two-dimensional pressure servo valve.

The front end cover is fixedly connected with the pump body through screws; the rear end cover is fixedly connected with the pump body through a screw; the duplex plunger pump is fixed in the pump body; the two-dimensional pulse width modulation mechanism and the two-dimensional pressure servo valve are fixedly connected with the pump body through screws.

And a driving gear, a driven gear and a deep groove ball bearing are arranged in the front end cover, the driving gear is fixedly connected with a motor coupler, and the driven gear is fixedly connected with a two-dimensional pulse width modulation mechanism.

The pump body is equipped with inlet port, oil outlet, first through-hole, second through-hole, third blind hole. The oil outlet is arranged at the top of the pump body, the first through hole is arranged at the lower part of the pump body and communicated with the oil inlet, and a duplex plunger pump is installed. The second through hole is arranged at the upper part of the pump body and is provided with a two-dimensional pulse width modulation mechanism. The third blind hole is formed in the upper portion of the pump body and provided with a two-dimensional pressure servo valve.

The duplex plunger pump comprises an upper pump core and a lower pump core, wherein the upper pump core is close to the front end cover, and the lower pump core is close to the rear end cover.

The upper pump core comprises an upper cylinder body, an upper plunger, an upper left end structural shaft, an upper right end structural shaft, a first concentric ring, a second concentric ring, an upper left guide rail, an upper right guide rail and a positioning pin. The upper-linked plunger is installed in the upper-linked cylinder body, the left end and the right end of the upper-linked plunger are fixedly connected with an upper-linked left end structural shaft and an upper-linked right end structural shaft through positioning pins respectively, and the left side and the right side of the upper-linked plunger are provided with a first concentric ring and a second concentric ring respectively. The left end and the right end of the upper cylinder body are fixedly connected with an upper connection left guide rail and an upper connection right guide rail which are provided with equal deceleration curved surface tracks, the equal deceleration curved surface tracks of the upper connection left guide rail and the upper connection right guide rail are circumferentially staggered by 90 degrees, namely, the highest point and the lowest point of the upper connection left guide rail equal deceleration curved surface track correspond to the lowest point and the highest point of the upper connection right guide rail equal deceleration curved surface track.

A shoulder is arranged in the middle of the upper connecting plunger, four rectangular distributing grooves are uniformly distributed on the surface of the upper connecting plunger, and the positions of notches of the four rectangular distributing grooves are staggered.

Four flow distribution windows are uniformly distributed on the upper cylinder body and respectively comprise two oil inlets and two oil outlets, the oil inlets and the oil outlets are alternately arranged, low-pressure oil is introduced into the oil inlets, high-pressure oil is introduced into the oil outlets, and the oil inlets and the oil outlets are not communicated with each other. And two sides of the oil outlet are sealed by sealing rings. The flow distribution window is arranged corresponding to the flow distribution groove on the upper-linked plunger.

The upper-connection left-end structural shaft comprises a first structural shaft main body, a first large roller, a second large roller, a first small roller pair and a second small roller pair. The second big roller wheel and the first big roller wheel have the same structure to form a first big roller wheel group. The second small roller pair and the first small roller pair have the same structure to form a first small roller group. The first large roller comprises a conical roller bearing sleeve and a deep groove ball bearing, the outer part of the bearing sleeve is a conical surface, the inner part of the bearing sleeve is a round hole, and the inner hole of the bearing sleeve is sleeved on the outer circle of the deep groove ball bearing and is fixedly connected with the outer circle of the deep groove ball bearing. The first small roller pair comprises a large cylindrical roller and a small cylindrical roller, the large cylindrical roller comprises a cylindrical bearing sleeve and a deep groove ball bearing, the outside of the bearing sleeve is a cylinder, the inside of the bearing sleeve is a round hole, and the inner hole of the bearing sleeve is sleeved on the excircle of the deep groove ball bearing and is fixedly connected with the excircle of the deep groove ball bearing. The small cylindrical roller comprises a cylindrical roller sleeve and a copper sleeve, the outside of the roller sleeve is a cylinder, the inside of the roller sleeve is a round hole, and the inner hole of the roller sleeve is sleeved on the outer circle of the copper sleeve and fixedly connected with the outer circle of the copper sleeve. The first large roller and the second large roller are fixedly connected to two ends of the first structural shaft main body through nuts and are arranged in an axial symmetry mode. The first small roller pair and the second small roller pair are fixedly connected to two ends of the first structure shaft main body through positioning pins and are arranged in a central symmetry mode.

The upper-connection right-end structural shaft is identical to the left-end structural shaft in structure.

The rolling surfaces of the large roller groups of the upper left end structural shaft and the upper right end structural shaft are respectively matched with the corresponding upper left guide rail and the upper right guide rail, and the rolling surface of the small roller group of the upper left end structural shaft is matched with a track carried by the motor coupler; and the rolling surface of the small roller set of the upper coupling right-end structural shaft is matched with a track carried by a shifting fork structure of the third structural shaft main body.

The space that first concentric ring, upper reaches and allies oneself with plunger and upper reaches and allies oneself with the cylinder body and enclose jointly constitutes first left cavity, the space that second concentric ring, upper reaches and allies oneself with plunger and upper reaches and allies oneself with the cylinder body and encloses jointly constitutes first right cavity, and the volume of first left cavity and first right cavity is along with the alternating motion of plunger and is crisscross change.

The lower pump core comprises a lower cylinder body, a lower plunger, a lower left end structure shaft, a lower right end structure shaft, a third concentric ring, a fourth concentric ring, a lower left guide rail, a lower right guide rail and a positioning pin. The lower-link plunger is installed in the lower-link cylinder body, the left end and the right end of the lower-link plunger are fixedly connected with a lower-link left end structural shaft and a lower-link right end structural shaft through positioning pins respectively, and a third concentric ring and a fourth concentric ring are installed on the left side and the right side of the lower-link plunger respectively. The left end and the right end of the lower cylinder body are fixedly connected with a lower left guide rail and a lower right guide rail which are provided with the same equal-acceleration and equal-deceleration curved surface tracks. The arrangement mode of the lower left guide rail and the lower right guide rail is the same as that of the upper left guide rail and the upper right guide rail.

The lower cylinder body is identical to the upper cylinder body in structure.

The lower-linked plunger piston and the upper-linked plunger piston are identical in structure, and the upper-linked plunger piston and the lower-linked plunger piston are concentrically arranged.

The lower-connection left-end structural shaft comprises a third structural shaft main body and a third large roller set. The third structural shaft main body is provided with a shifting fork structure which is matched and connected with a small roller set of the upper coupling right end structural shaft, so that the upper coupling pump core and the lower coupling pump core are staggered by 45 degrees in space. The right structural shaft of the lower connector comprises a fourth structural shaft main body and a fourth big roller group. The third large roller group and the fourth large roller group have the same structure as the first large roller group of the upper-linked left-end structural shaft, and the placement modes are also the same. The rolling surfaces of the third large roller group and the fourth large roller group of the lower-joint left-end structural shaft and the lower-joint right-end structural shaft are respectively matched with a lower-joint left guide rail and a lower-joint right guide rail on the lower-joint cylinder body.

The third concentric ring, the space enclosed by the lower-connected plunger piston and the lower-connected cylinder body form a second left chamber, the space enclosed by the fourth concentric ring, the lower-connected plunger piston and the lower-connected cylinder body form a second right chamber, and the volumes of the second left chamber and the second right chamber are changed in a staggered mode along with the reciprocating motion of the plunger piston.

When the duplex plunger pump works, the upper-linked plunger and the lower-linked plunger rotate circumferentially together due to the matching connection of the upper-linked right-end structural shaft and the lower-linked left-end structural shaft, the large roller groups of the upper-linked left and right structural shafts and the large roller groups of the lower-linked left and right structural shafts are respectively arranged on the left equal-deceleration curved surface track and the right equal-deceleration curved surface track, and the upper-linked plunger and the lower-linked plunger must do reciprocating motion in the axial direction due to the constraint of the curved surface tracks when the large roller groups rotate circumferentially. Along with the reciprocating motion of the plunger, the volumes of the first left chamber, the first right chamber, the second left chamber and the second right chamber are changed in a staggered mode, the flow distribution grooves in the plunger are communicated with the flow distribution windows in the corresponding cylinder bodies alternately, the chambers with gradually-increased volumes absorb oil from the oil tank, and the chambers with gradually-decreased volumes discharge oil outwards, so that continuous oil suction and discharge are achieved.

The two-dimensional pulse width modulation mechanism is characterized in that: the hydraulic valve comprises a transmission shaft, a zero position spring, a roller shaft, a left roller assembly, a right roller assembly, a front concentric ring, a first valve core, a first valve sleeve, a rear concentric ring and a first valve core plug. The transmission shaft shifting fork is matched with the roller component to shift the first valve core through the roller shaft, so that the first valve core rotates circumferentially and slides axially in the first valve sleeve, the rotation and the axial sliding of the first valve core are relatively independent, the front concentric ring and the rear concentric ring are fixedly connected to two ends of the first valve sleeve respectively, and the zero-position spring is arranged between the first valve core and the transmission shaft and is in a compressed state.

One end of the transmission shaft is a cylindrical end and is connected with the transmission mechanism; the other end of the transmission shaft is in a door frame shape and is connected with two U-shaped shifting forks, and the shifting fork surfaces are axial incomplete cylindrical surface tracks and are matched with the left roller assembly and the right roller assembly to enable the first valve core to axially slide while circumferentially rotating; the axial middle end surface of the transmission shaft is provided with a circular groove for fixing the zero spring.

Two flat end faces of the zero-position spring are respectively fixed at the circular groove of the transmission shaft and the stepped shaft at the left end of the first valve core, the zero-position spring is in a compressed state in the initial and working processes, the first valve core is ensured to be at the rightmost end in the initial state, and the zero position of the first valve core is kept.

The roller shaft is a stepped cylindrical shaft, a shoulder is arranged in the middle of the stepped cylindrical shaft, and the diameter of the middle cylinder is larger than that of the cylinders at the two sides; the middle shoulder shaft is inserted into the cylindrical hole at the left end of the first valve core and fixedly connected with the cylindrical hole, and the two end shafts are respectively inserted into the central round holes of the left roller assembly and the right roller assembly and fixedly connected with the central round holes of the left roller assembly and the right roller assembly.

The right roller assembly and the left roller assembly are completely the same in structure and comprise a bearing sleeve and a deep groove ball bearing, the outer portion of the bearing sleeve is a spherical surface, the inner portion of the bearing sleeve is a circular hole, two ends of the bearing sleeve are flat end surfaces, an inner hole of the bearing sleeve is sleeved on the outer circle of the deep groove ball bearing and fixedly connected with the outer circle of the deep groove ball bearing, and the spherical surface of the bearing sleeve is matched with the cylindrical surface.

The front concentric ring is circular, two end faces are planes, the outer circle of the front concentric ring is fixedly connected with the first valve sleeve, and the inner hole is sleeved on the shaft at the left end of the first valve core.

The back concentric ring is circular, two end faces are planes, an inner hole is provided with a stepped hole to provide an avoiding space for the second circular through hole of the first valve core, the outer circle of the back concentric ring is fixedly connected with the first valve sleeve, and the inner hole is sleeved on the shaft at the right end of the first valve core.

The inner hole of the first valve sleeve is a central through hole and is matched with the first valve core, and a front stepped hole and a rear stepped hole are respectively arranged at two ends and are respectively fixedly connected with a front concentric ring and a rear concentric ring; the excircle of first valve barrel is equipped with four ring channels, from left to right respectively is control oil groove, goes out the oil groove, oil feed tank and oil return tank, evenly is equipped with a plurality of the same radial control oilholes on the control oil groove, evenly is equipped with a plurality of the same radial oil outlet on going out the oil groove, evenly is equipped with a plurality of the same radial rhombus flow distribution windows on the oil feed tank, the summit of rhombus flow distribution window just this plane perpendicular to first case axis in the coplanar, evenly is equipped with a plurality of the same radial oil return ports on the oil return tank.

The leftmost end of the first valve core is provided with a step shaft for mounting a zero position spring, and the right side of the step shaft is provided with a roller shaft circular through hole which is fixedly connected with the roller shaft and used for transmitting torque to the first valve core to enable the first valve core to rotate; the first valve core is provided with three shoulders, a first shoulder, a second shoulder and a third shoulder are sequentially arranged from left to right, a first circular through hole is radially arranged on a first valve core shaft between the first shoulder and the second shoulder, a second circular through hole is radially arranged on the first valve core shaft close to the right end face of the third shoulder, a central flow passage is axially arranged in the center of the first valve core, a central flow passage port is plugged by a first valve core in a plugging manner, and the first circular through hole is communicated with the second circular through hole through the first valve core central flow passage; two lines of staggered triangular flow distribution windows, namely a left triangular flow distribution window and a right triangular flow distribution window, are arranged on the second shoulder of the first valve core, the vertex of the triangular flow distribution windows is in the same plane, and the plane is vertical to the axis of the first valve core.

The bearing sleeve outer circle spherical surface and the transmission shaft U-shaped shifting fork are in clearance fit, and are in unilateral contact when stressed, so that positive and negative rotation can be realized, the transmission shaft drives the first valve core to rotate through the left roller assembly, the right roller assembly and the roller shaft, the first valve core axially slides under the action of hydraulic pressure, and the bearing sleeve is driven to axially roll on the transmission shaft U-shaped shifting fork.

The outer circles of the front concentric ring and the rear concentric ring are fixedly connected in a front stepped hole and a rear stepped hole of two end faces of the first valve sleeve respectively, an inner hole of the front concentric ring is sleeved on a shaft at the left end of the first valve core and is sealed by a gap, and an inner hole of the rear concentric ring is sleeved on a shaft at the right end of the first valve core and is sealed by a gap.

The first valve core is rotatably arranged in the first valve sleeve, the front concentric ring and a first shoulder of the first valve core seal an inner cavity of the first valve sleeve to form a control cavity, the control cavity is communicated with the control oil groove through the control oil hole, and the control oil groove is communicated with control pressure oil; the first shoulder and the second shoulder of the first valve core seal the inner cavity of the first valve sleeve to form a high-pressure cavity, the high-pressure cavity is communicated with the oil outlet groove through the oil outlet hole and is communicated with the oil inlet groove through the rhombic flow distribution window, high-pressure oil of the hydraulic pump is introduced into the oil inlet groove, and a system oil way is introduced into the oil outlet groove; the second shoulder and the third shoulder of the first valve core seal the inner cavity of the first valve sleeve to form a low-pressure cavity, the low-pressure cavity is communicated with the oil return groove through the oil return hole, and the oil return groove is communicated with a low-pressure oil tank; the third shoulder of the first valve core and the rear concentric ring seal the inner cavity of the first valve sleeve to form a feedback cavity, the feedback cavity is communicated with the high-pressure cavity through the first circular through hole, the central flow channel and the second circular through hole of the first valve core, and the pressures of the two cavities are the same; the first valve sleeve controls the oil groove, the oil outlet groove, the oil inlet groove and the oil return groove to be not communicated with each other outside the first valve sleeve. Two rows of staggered triangular flow distribution windows are formed in the second shoulder of the first valve core and are respectively a left triangular flow distribution window and a right triangular flow distribution window, the rhombic flow distribution window of the first valve sleeve is positioned on the motion track of the second shoulder of the first valve core, and the first valve core axially slides under the action of hydraulic pressure while rotating at a constant speed in the first valve sleeve, so that the flow distribution time ratio of the left triangular flow distribution window and the right triangular flow distribution window of the first valve core to the rhombic flow distribution window of the first valve sleeve is changed, and the flow distribution of the outlet oil is changed.

The two-dimensional pressure servo valve is characterized in that: the displacement sensor module is matched with the valve body module, and the electro-mechanical converter module is matched with the valve body module; the displacement sensor module monitors the displacement of the 2D piston in the valve body module in real time and the torque motor electric signal of the electric-mechanical converter module to form closed-loop feedback.

The valve body module comprises a second valve core, a second valve core shell, a 2D piston, a left gasket, a right gasket, a concentric ring, a pressure regulating spring, a second valve sleeve, a valve sleeve plug and a positioning pin. The second valve core is arranged in an inner hole of a second valve core shell, the 2D piston is arranged on the right side of the second valve sleeve, the valve sleeve plug is fixedly connected to the left end portion of the second valve sleeve through a positioning pin, and the second valve core shell is positioned through the valve sleeve plug and fixed to the left side of the second valve sleeve. The right-hand member at the second case is connected to the left gasket, and the left end at the 2D piston is connected to the right gasket, is connected with pressure regulating spring between left gasket and the right gasket, and 2D piston right side is provided with the concentric ring.

The second valve sleeve is provided with three annular grooves which are respectively an oil inlet groove, an oil outlet groove and an oil return groove from left to right, a plurality of same radial oil inlet holes are uniformly formed in the oil inlet groove, a plurality of same radial oil outlet holes are uniformly formed in the oil outlet groove, and a plurality of same radial oil return holes are uniformly formed in the oil return groove. And a pair of damping chutes matched with the high-low pressure grooves on the 2D piston shoulder are formed in the inner hole wall on the right side of the second valve sleeve. And O-shaped sealing rings are arranged on two sides of each oil port of the second valve sleeve, so that the local sealing of the servo valve is ensured.

The 2D piston is arranged in the second valve sleeve, and two movement directions of circumferential rotation and axial sliding are arranged in the second valve sleeve; the left end of the 2D piston is provided with a shoulder, the shoulder is provided with a pair of high-pressure grooves and a pair of low-pressure grooves in a matched mode, the shoulder is matched with a pair of damping chutes formed in the wall of the second valve sleeve, the pair of high-pressure grooves are communicated with the oil inlet hole, the pair of low-pressure grooves are communicated with the oil return hole, the shoulder and the concentric ring of the 2D piston and the second valve sleeve are sealed to form a left sensitive cavity and a right sensitive cavity, the pair of high-pressure grooves and the pair of low-pressure grooves in the shoulder of the 2D piston are intersected with the pair of damping chutes to form four tiny opening areas which are connected in series to form a hydraulic resistance half bridge, pressure change of the left sensitive cavity is controlled by the hydraulic resistance half bridge, the right sensitive cavity is communicated with the oil inlet hole, and the.

The second valve core shell is uniformly provided with 4 same radial through holes on a shoulder at the left end, and the through holes are communicated with the oil inlet; and 4 same radial through holes are uniformly formed in the annular groove on the right side of the second valve core shell and are communicated with the oil outlet. The second valve core shell is matched with the valve sleeve plug to form a control cavity.

And the left side and the right side of the second valve core are respectively provided with a shoulder which is matched with the shell of the second valve core, and the opening degrees of the oil inlet and the oil return port are changed when the second valve core moves axially. The left end face of the second valve core is designed to be a disc-shaped structure, when the second valve core moves left and right, an extrusion oil film is formed between the disc-shaped structure of the second valve core and a closed cavity formed by the second valve core shell and the valve sleeve plug, and the extrusion oil film has the functions of introducing an extrusion oil film damping coefficient, increasing the viscous damping of a system and improving the damping ratio to enable the system to be more stable. The second valve core is internally provided with a central flow passage which is connected with a through hole at the right side of the second valve core and is communicated with the control cavity.

When the 2D piston rotates clockwise (from one side of the transmission mechanism to the left), the intersection area of the high-pressure groove and the damping chute is reduced, the intersection area of the low-pressure groove and the damping chute is increased, the pressure of the left sensitive cavity is reduced, the pressure of the right sensitive cavity is unchanged, and the 2D piston moves to the left. In the left moving process, the intersection area of the high-pressure groove and the damping chute is increased, the intersection area of the low-pressure groove and the damping chute is reduced, the pressure of the left sensitive cavity is gradually increased, and the 2D piston is finally stabilized at a certain position. The 2D piston moves left to generate a left force, the force is transmitted to the second valve core through the pressure regulating spring, the right end of the second valve core is stressed to be increased, the original liquid pressure balance fails, the second valve core moves left, the opening degree of a valve port is increased through the left movement of the second valve core, the pressure of an oil outlet is increased, the oil outlet is communicated with the control cavity, the left end face of the second valve core is subjected to rightward hydraulic pressure increase, when the rightward hydraulic pressure is smaller than the pressure regulating spring force, the second valve core continues to move left, the opening degree of the valve port continues to be increased, and the output pressure continues; when the hydraulic pressure to the right is equal to the pressure regulating spring force, the second valve spool stops moving to the left and is stabilized at a certain position, and meanwhile, the pressure of the oil outlet is kept to be basically a constant value.

The electric-mechanical converter module adopts a torque motor and comprises a shell, an armature, a permanent magnet, a magnetizer, a clamping piece, a motor outer cover, a coil, a spring rod, a spring seat, a limiting rod and a connecting plate, wherein the shell and the motor outer cover are connected with the connecting plate, the shell is fixedly connected with the connecting plate through a screw, one end of the spring is connected with the spring rod, and the other end of the spring is connected with the spring seat fixed on the shell. The electro-mechanical converter module is connected with the valve body through a connecting plate. The two-dimensional pressure servo valve adopts a dry torque motor, so O-shaped sealing rings are also arranged on a motor outer cover and a connecting plate, and an output part is sealed to prevent oil from entering a space around the armature, the coil and the permanent magnet.

The electro-mechanical converter module includes a magnetic circuit portion, a transmission portion, and a motor housing. The connecting plate is connected with the motor outer cover through screws. The magnetic circuit part consists of 2 coils, 2 magnetizers, 1 armature and 2 permanent magnets. When the coil is not electrified, the armature keeps balance; energization of the coil creates a magnetic path that disrupts the previous equilibrium state and the armature deflects. The transmission part comprises a spring, a spring seat, a spring rod, a limiting rod and a motor pin. And the shell and the clamping piece are used for fixing and positioning the parts. When the armature deflects, the 2D piston and the spring rod are driven to rotate. One end of the spring is connected with the spring rod, and the other end of the spring is connected with the spring seat fixedly connected to the shell, so that the rotary motion of the spring rod can be effectively transmitted to the spring, and the spring is ensured to automatically return to zero under the abnormal condition, so that the armature and the 2D piston return to the initial position.

The displacement sensor module comprises an LVDT connecting rod and an LVDT sensor (consisting of an iron core and a coil framework), the LVDT sensor is matched with the shell and the arc of the clamping piece, and the clamping piece is pressed tightly by a screw to fix the LVDT sensor; the spring rod is vertically connected with the LVDT connecting rod; the LVDT connecting rod is connected with the iron core, and the iron core and the LVDT sensor adopt clearance fit and can move in the inner hole of the LVDT sensor. And the LVDT sensor is connected with the 2D piston of the valve body module through a threaded connecting rod.

In the working process of the torque motor, the armature drives the spring rod and the 2D piston to rotate, the 2D piston moves linearly by combining the 2D servo spiral theorem, the spring rod and the iron core are driven to move linearly simultaneously, and the displacement of the iron core is transmitted to the controller in the form of an electric signal by combining the LVDT principle, so that the closed-loop control of the displacement of the second valve core is realized.

A plurality of oil paths are arranged in the pump body, and an oil inlet tank of the two-dimensional pulse width modulation mechanism is communicated with an oil outlet of the duplex plunger pump through the oil paths; an oil outlet groove of the two-dimensional pulse width modulation mechanism is communicated with an oil outlet of the pump body; an oil return groove of the two-dimensional pulse width modulation mechanism is communicated with a system oil tank; a control oil groove of the two-dimensional pulse width modulation mechanism is communicated with an oil outlet groove of the two-dimensional pressure servo valve; an oil inlet tank of the two-dimensional pulse width modulation mechanism is communicated with an oil inlet tank of the two-dimensional pressure servo valve; and an oil return groove of the two-dimensional pulse width modulation mechanism is communicated with an oil return groove of the two-dimensional pressure servo valve.

The specific working process is as follows:

when an external motor is started, the upper-linked plunger is driven by the motor coupler to rotate at a constant speed, and the upper-linked plunger and the lower-linked plunger are connected in a matched manner, so that the upper-linked plunger and the lower-linked plunger rotate circumferentially together, the large roller sets of the upper-linked left structure shaft and the lower-linked left structure shaft are arranged on the corresponding upper-linked left rail and lower-linked left rail, and the large roller sets of the upper-linked right structure shaft and the lower-linked right structure shaft are arranged on the corresponding upper-linked right rail and lower-linked right rail. Therefore, the upper plunger and the lower plunger can axially and continuously reciprocate along with the continuous rolling of the large roller groups on the corresponding left and right equal-speed reducing curved surface tracks.

Continuous circumferential rotation and axial reciprocating motion of the plunger piston enable a groove in the plunger piston to be communicated with a window in the cylinder body periodically, a cavity with gradually-increased volume absorbs oil from the oil tank through the communicated groove and window, and a cavity with gradually-decreased volume discharges oil in the cavity through the communicated rectangular groove and window; the reciprocating motion of the plunger piston enables the volumes of the left cavity and the right cavity to change continuously in a staggered mode, and continuous oil suction and discharge are achieved.

The oil discharged by the duplex plunger pump is introduced into the pressure servo variable mechanism through the pump body liquid channel. Due to gear transmission, the pressure servo variable mechanism and the upper pump core start to work simultaneously.

The pressure servo variable mechanism has two working states of constant pressure variable and pressure servo.

When the two-dimensional pressure servo valve does not receive a given signal or a system given feedback signal, the system pressure is unchanged in the working process of a constant pressure variable state, and at the moment, if the system flow is changed, the system pressure is slightly changed. When the required flow of the system is increased, the pressure of the system is reduced, namely the pressure of the feedback containing cavity is reduced, the balance state of the left end and the right end of a first valve core of the two-dimensional pulse width modulation mechanism is broken, the resultant force of the left end of the first valve core is greater than the resultant force of the right end of the first valve core, so that the first valve core of the two-dimensional pulse width modulation mechanism moves rightwards, the opening degree of an oil inlet and an oil outlet is increased, the opening time is prolonged, more flow flows flow into the system to supply energy to the system, the pressure of the feedback containing. On the contrary, when the required flow of the system is reduced, the pressure of the system is increased, namely the pressure of the feedback containing cavity is increased, the balance state of the left end and the right end of the first valve core is broken, the resultant force of the left end of the first valve core is smaller than the resultant force of the right end of the first valve core, the first valve core moves leftwards, the opening degree of the oil inlet and the oil return opening is increased, the opening time is prolonged, more flow flows back to the oil tank to reduce the oil supply amount in the system, and the pressure of the feedback containing cavity is reduced.

When the two-dimensional pressure servo valve receives a given signal or a system given feedback signal, the two-dimensional pressure servo valve is in a working process of a pressure servo state, the torque motor drives the 2D piston to rotate in the circumferential direction, a certain displacement is axially output due to the change of the pressure difference of the left sensitive cavity and the right sensitive cavity, force is transmitted to the second valve core through the pressure regulating spring, the hydraulic pressure applied to the second valve core is unbalanced with the pressure regulating spring force and moves in the axial direction, the opening degree of a valve port is changed, the output pressure is changed until the hydraulic pressure applied to the left end face of the second valve core is balanced with the pressure regulating spring force again, the outlet pressure of the servo valve is basically a fixed value. The oil outlet of the two-dimensional pressure servo valve is communicated with the control containing cavity of the two-dimensional pulse width modulation mechanism, so that the pressure of the oil outlet of the two-dimensional pressure servo valve changes, the original balance state of a first valve core of the two-dimensional pulse width modulation mechanism is broken, the first valve core moves axially, the ratio of the time required by a left triangular flow distribution window and a right triangular flow distribution window of the first valve core to the total time respectively and alternately swept through a rhombic flow distribution window of the first valve sleeve changes correspondingly, the oil outlet flow and the oil return flow change correspondingly, the flow entering the system changes correspondingly, the pressure of the feedback containing cavity changes correspondingly, and the first valve core reaches a new balance state and the pressure of the system is constant again until the axial resultant force of the first valve core is balanced again.

When the pressure of the system needs to be reduced, the pressure difference between the left sensitive cavity and the right sensitive cavity of the 2D piston is reduced, the second valve core moves rightwards to reduce the opening degree of a valve port, a pressure oil port is communicated with the control cavity, the hydraulic pressure of the left end face of the second valve core to the right is reduced, and the pressure is balanced with the pressure regulating spring force. When the output pressure is greater than the set pressure value, the hydraulic pressure received by the left end face of the second valve core is greater than the pressure regulating spring force, the second valve core continues to move to the right, the opening of the valve port continues to be reduced, the output pressure continues to be reduced, when the output pressure reaches the set value of the valve, the hydraulic pressure received by the second valve core reaches balance again, the opening of the valve port is reduced at the moment, the pressure of the oil outlet is reduced, and the pressure of the oil outlet is kept to be basically a fixed value. The oil outlet pressure of the two-dimensional pressure servo valve is reduced, so that the pressure of a control cavity of the two-dimensional pulse width modulation mechanism is reduced, the left end resultant force of the first valve core is smaller than the right end resultant force, the first valve core moves leftwards, the opening degree of a valve port of the oil inlet is reduced (until the valve port is completely closed), the pressure of the oil outlet is reduced along with the loss of oil in the system, and the first valve core reaches a new balance state until the two end resultant forces of the first valve core are equal again, so that the pressure reduction effect is realized, and the pressure of.

On the contrary, when the system pressure needs to be increased, the pressure difference between the left sensitive cavity and the right sensitive cavity of the 2D piston is increased, the second valve core moves leftwards to increase the opening degree of the valve port, the hydraulic pressure of the left end face of the second valve core to the right is increased, and the force is balanced with the pressure regulating spring force. When the output pressure is smaller than the set pressure value, the hydraulic pressure on the left end face of the second valve core is smaller than the pressure regulating spring force, the second valve core continues to move leftwards, the opening degree of the valve port continues to increase, and the output pressure continues to increase; when the output pressure reaches the set pressure value of the valve, the hydraulic pressure borne by the second valve core reaches balance again, the opening degree of the valve port is increased, the pressure of the oil outlet is increased, and the pressure of the oil outlet is kept to be a fixed value basically. The oil outlet pressure of the two-dimensional pressure servo valve is increased, so that the pressure of a control cavity of the two-dimensional pulse width modulation mechanism is increased, the left end resultant force of the first valve core is larger than the right end resultant force, the first valve core moves rightwards, the opening degree of a valve port of an oil return port is reduced (till the valve port is completely closed), the oil outlet pressure is increased along with the inflow of a large amount of oil in the system, and the first valve core reaches a new balance state till the two end resultant forces of the first valve core are equal again, so that the pressurization effect is realized, and the pressure.

Through the actions, the continuous oil suction and discharge work of the duplex plunger pump is realized, the synchronous work of the duplex plunger pump and the pressure servo variable mechanism is realized, the constant pressure of the system is kept when the flow of the system is changed by the pressure servo variable pump, and the system tends to be stable again after the pressure of the system is increased or decreased when an external given signal is generated, so that a new constant pressure environment is formed.

The axial direction involved in the double plunger pump refers to the direction of the central axis of the plunger; reference to radial refers to a direction perpendicular to the central axis of the plunger; the circumferential direction referred to refers to the direction in which the plunger rotates about the central axis; reference to axial symmetry refers to symmetry about the central axis of the plunger; reference to central symmetry refers to point symmetry about the plunger center.

The axial direction involved in the two-dimensional pulse width modulation mechanism refers to the direction of a central shaft of a first valve core of the pulse width modulation mechanism; the referred radial direction refers to the direction perpendicular to the central axis of the first valve core of the pulse width modulation mechanism; the circumferential direction referred to refers to the direction in which the first spool of the pulse width modulation mechanism rotates about the central axis.

The axial direction involved in the two-dimensional pressure servo valve refers to the direction in which the 2D piston central axis of the two-dimensional pressure servo valve is located; the radial direction referred to refers to the direction in which the 2D piston center axis of the two-dimensional pressure servo valve is perpendicular; the circumferential direction referred to refers to the direction in which the 2D piston of the two-dimensional pressure servo valve rotates around the central axis.

The invention has the beneficial effects that:

1. the invention realizes the adjustable system pressure constant pressure flow distribution through the pressure servo variable mechanism, and has the advantages of wide pressure flow regulation range, continuous regulation, high sensitivity and high response speed.

2. Compared with the traditional servo pump, the invention does not need a servo motor when the pressure and the flow are changed in a servo mode, and can realize the adjustment of the pressure and the flow of the system at the same time;

3. the two-dimensional pressure servo valve has a wide signal input range, can input a required signal automatically, and can give a feedback signal according to the system pressure or some local pressure of the system to realize pressure and flow regulation.

4. The two-dimensional (2D) pump valve group control flow distribution in the prior art is replaced, the adjusting mechanism is reduced, and the design is simplified.

Drawings

FIG. 1a is a schematic diagram of a two-dimensional pressure servo variable pump.

FIG. 1b is a schematic diagram of a two-dimensional pressure servo variable mechanism.

Fig. 2 is a schematic diagram of a pump body structure.

Fig. 3a is a schematic structural diagram of an upper pump core.

Fig. 3b is an exploded view of the upper pump core.

Fig. 4 is an exploded view of the upper left end structural shaft.

Fig. 5a is a structural schematic diagram of a lower pump core.

Fig. 5b is an exploded view of the lower pump core.

FIGS. 6a 1-6 c2 are schematic diagrams of the working principle of the duplex plunger pump,

Wherein FIG. 6a1 is a schematic view of the plunger with the upper link moving to the far left;

FIG. 6a2 is a cross-sectional view taken along line A-A of FIG. 6a 1;

FIG. 6b1 is a schematic view of the plunger with the upper link moving to a neutral position;

FIG. 6b2 is a cross-sectional view taken along line A-A of FIG. 6b 1;

FIG. 6c1 is a schematic view of the plunger with the upper link moving to the rightmost end;

FIG. 6c2 is a cross-sectional view taken along line A-A of FIG. 6c 1.

Fig. 7 is a schematic diagram of a two-dimensional pulse width modulation mechanism.

Fig. 8a is a schematic view of a first valve sleeve configuration of a two-dimensional pulse width modulation mechanism.

Fig. 8b is a cross-sectional view a-a of fig. 8 a.

Fig. 9a is a schematic diagram of a first valve core structure of the two-dimensional pulse width modulation mechanism.

Fig. 9B is a cross-sectional view B-B of fig. 8 a.

Fig. 10 is a schematic structural diagram of a transmission shaft of the two-dimensional pulse width modulation mechanism.

Fig. 11 is a schematic structural diagram of a right roller assembly of the two-dimensional pulse width modulation mechanism.

Fig. 12 is a schematic structural diagram of a roller shaft of the two-dimensional pulse width modulation mechanism.

Fig. 13a is a schematic diagram of a two-dimensional pulse width modulation mechanism first valve sleeve flow distribution window.

Fig. 13b is a schematic diagram of the first valve core flow distribution window of the two-dimensional pulse width modulation mechanism.

Fig. 13c is a schematic diagram of the flow distribution principle when the first valve core of the two-dimensional pulse width modulation mechanism is in a neutral position.

Fig. 13d is a schematic diagram of the flow distribution principle when the first valve core of the two-dimensional pulse width modulation mechanism moves downwards.

Fig. 14a is a schematic perspective view e of a two-dimensional pressure servo valve.

Fig. 14b is an axial cross-sectional view of fig. 14 a.

Fig. 15a is a schematic diagram of a two-dimensional pressure servo valve 2D piston structure.

Fig. 15b is a cross-sectional view taken along line C-C of fig. 15 a.

FIG. 16a is a schematic diagram of a two-dimensional pressure servo valve second valve housing configuration.

Fig. 16b is a cross-sectional view taken along line D-D of fig. 16 a.

Fig. 17a is a perspective view of a second spool of the two-dimensional pressure servo valve.

Fig. 17b is an axial cross-sectional view of fig. 17 a.

Fig. 18a is a perspective view of a second spool housing of the two-dimensional pressure servo valve.

Fig. 18b is an axial cross-sectional view of fig. 18 a.

Fig. 19a is a schematic perspective view of a two-dimensional pressure servo valve torque motor.

Fig. 19b is an axial cross-sectional view of fig. 19 a.

Fig. 20 is a schematic diagram of the operation of a two-dimensional pressure servo variable pump.

Detailed Description

The solution of the invention is further explained below with reference to fig. 1a to 20.

The working principle of the example is as follows:

the two-dimensional pressure servo variable pump is characterized in that: the device comprises a front end cover 1, a pump body 8, a rear end cover 9, a duplex plunger pump 6 and a pressure servo variable mechanism 10. The pressure servo variable mechanism comprises a two-dimensional pulse width modulation mechanism 11 and a two-dimensional pressure servo valve 12.

The front end cover 1 is fixedly connected with the pump body 8 through screws; the rear end cover 9 is fixedly connected with the pump body 8 through screws; the duplex plunger pump 6 is fixed in the pump body 8; the two-dimensional pulse width modulation mechanism 11 and the two-dimensional pressure servo valve 12 are fixedly connected with the pump body through screws.

A driving gear 2, a driven gear 4 and a deep groove ball bearing 3 are arranged in the front end cover 1, the driving gear 2 is fixedly connected with a motor coupler, and the driven gear 4 is fixedly connected with a two-dimensional pulse width modulation mechanism 11.

The pump body is provided with a first through hole (namely an oil inlet) m1, a second through hole m2, a third blind hole m3 and an oil outlet m 4. First through-hole m1 establishes in the pump body 8 lower part, installs pair plunger pump 6, second through-hole m2 establishes on the pump body 8 upper portion, installs two-dimensional pulse width modulation mechanism 11, third blind hole m3 establishes on the pump body 8 upper portion, installs two-dimensional pressure servo valve 12.

The duplex plunger pump 6 comprises an upper pump core 5 and a lower pump core 7, wherein the upper pump core 5 is close to the front end cover 1, and the lower pump core 7 is close to the rear end cover 9.

The upper pump core 5 comprises an upper cylinder 509, an upper plunger 504, an upper left structural shaft 501, an upper right structural shaft 507, a first concentric ring 503, a second concentric ring 505, an upper left guide rail 510, an upper right guide rail 508 and positioning pins 502 and 506. The upper coupling plunger 504 is installed in an upper coupling cylinder 509, the left end and the right end of the upper coupling plunger 504 are fixedly connected with an upper coupling left end structural shaft 501 and an upper coupling right end structural shaft 507 through positioning pins 502 and 506 respectively, and the left side and the right side of the upper coupling plunger 504 are provided with a first concentric ring 503 and a second concentric ring 505 respectively. The left end and the right end of the upper cylinder 509 are fixedly connected with an upper left guide rail 510 and an upper right guide rail 508 which are provided with equal deceleration curved surface tracks, the circumferential directions of the equal deceleration curved surfaces of the upper left guide rail 510 and the upper right guide rail 508 are staggered by 90 degrees, namely, the highest point and the lowest point of the equal deceleration curved surface track of the upper left guide rail correspond to the lowest point and the highest point of the equal deceleration curved surface track of the upper right guide rail respectively.

The middle of the upper plunger 504 is provided with a shoulder, the surface of the upper plunger is provided with four rectangular distributing grooves a, b, c and d which are uniformly distributed, and the notch positions of the four rectangular distributing grooves are mutually staggered.

Four flow distribution windows e, f, g and h are uniformly distributed on the upper cylinder body and respectively comprise two oil inlets e and g and two oil outlets f and h, the oil inlets and the oil outlets are alternately arranged, low-pressure oil is introduced into the oil inlets, high-pressure oil is introduced into the oil outlets, and the oil inlets and the oil outlets are not communicated with each other. And two sides of the oil outlet are sealed by sealing rings. The flow distribution windows e, f, g, h are arranged corresponding to the flow distribution grooves a, b, c, d on the upper-linked plunger 504.

The upper-linked left end structural shaft 501 comprises a first structural shaft main body 501.2, a first large roller 501.1, a second large roller 501.6, a first small roller pair 501.7 and a second small roller pair 501.4. The second big roller 501.6 and the first big roller 501.1 have the same structure, and form a first big roller group 501.16. The second small roller pair 501.4 has the same structure as the first small roller pair 501.7, and forms a first small roller group 501.17. First big gyro wheel 501.1 includes toper gyro wheel bearing housing 501.14, deep groove ball bearing 501.13, and the bearing housing outside is the conical surface, and inside is the round hole, and the bearing housing hole cover is at the deep groove ball bearing excircle and links firmly, and first big gyro wheel 501.1 links firmly in first structure axle main part 501.2 with nut 501.15. First little gyro wheel is to 501.7 including one big one little two cylinder gyro wheels, big cylinder gyro wheel 501.3 includes cylinder bearing housing 501.9 and deep groove ball bearing 501.10, and the bearing housing outside is the cylinder, and inside is the round hole, and the bearing housing pot head is at deep groove ball bearing excircle and links firmly, and big cylinder is fixed in first structure axle main part 501.2 with locating pin 501.8. The small cylinder roller 501.5 comprises a cylinder roller sleeve 501.11 and a copper sleeve 501.12, the outside of the roller sleeve is a cylinder, the inside of the roller sleeve is a round hole, the inner hole of the roller sleeve is sleeved on the outer circle of the copper sleeve and fixedly connected with the outer circle of the copper sleeve, and the small cylinder roller is fixed on the first structure shaft main body 501.2. The first large roller 501.1 and the second large roller 501.6 are fixedly connected to two ends of the first structural shaft main body 510.2 and are arranged in axial symmetry. The first small roller pair 501.7 and the second small roller pair 501.4 are fixedly connected to two ends of the first structural shaft main body 501.2 and are arranged in a central symmetry manner.

The upper-coupling right end structural shaft 507 is identical to the upper-coupling left end structural shaft 501 in structure.

The rolling surfaces of the upper left end structure shaft 501, the first large roller set 501.16 and the second large roller set 507.2 of the upper right end structure shaft 507 are respectively matched with the corresponding upper left guide rail 510 and the upper right guide rail 508, and the rolling surface of the first small roller set 501.17 of the upper left end structure shaft 501 is matched with a track carried by a motor coupler; the rolling surface of the second small roller group 507.1 of the upper-coupling right-end structural shaft 507 is matched with the track carried by the shifting fork structure of the lower-coupling left-end structural shaft main body 702.

The space enclosed by the first concentric ring 503, the upper-linked plunger 504 and the upper-linked cylinder 509 forms a first left chamber, the space enclosed by the second concentric ring 505, the upper-linked plunger 504 and the upper-linked cylinder 509 forms a first right chamber, and the volumes of the first left chamber and the first right chamber are changed in a staggered manner along with the reciprocating motion of the plungers.

The lower pump core comprises a lower cylinder 713, a lower plunger 706, a lower left end structure shaft 701, a lower right end structure shaft 709, a third concentric ring 705, a fourth concentric ring 707, a lower left guide rail 714, a lower right guide rail 712 and positioning pins 704 and 708. The lower plunger 706 is installed in the lower cylinder 713, the left end and the right end of the lower plunger 706 are fixedly connected with the lower left end structural shaft 701 and the lower right end structural shaft 709 by positioning pins 704 and 708, and the left side and the right side of the lower plunger 706 are respectively provided with a third concentric ring 705 and a fourth concentric ring 707. The left end and the right end of the lower cylinder 713 are fixedly connected with a lower left guide rail 714 and a lower right guide rail 712 which are provided with the same deceleration curved surface track. The lower left 714 and lower right 712 rails are arranged in the same manner as the upper left 510 and upper right 508 rails.

The lower cylinder 713 is identical in structure to the upper cylinder 509.

The lower plunger 706 is identical in structure to the upper plunger 504, and the upper plunger 504 and the lower plunger 706 are concentrically disposed.

The lower-coupling left-end structural shaft 701 comprises a third structural shaft main body 702 and a third large roller group 703. The third structural shaft main body 702 is provided with a shifting fork structure and is matched and connected with a second small roller group 507.1 of the upper-linkage right-end structural shaft 507, so that the upper-linkage pump core 5 and the lower-linkage pump core 7 are staggered by 45 degrees in space.

The lower-coupling right structural shaft 709 includes a fourth structural shaft main body 711 and a fourth large roller group 710. The structure of the lower left end structure shaft 701, the third big roller group 703 and the fourth big roller group 710 of the lower right end structure shaft 709 are completely the same as the structure of the first big roller group 501.16 of the upper left end structure shaft, and the placing mode is also the same. The rolling surfaces of the lower left end structural shaft 701, the third large roller group 703 and the fourth large roller group 710 of the lower right end structural shaft 709 are respectively matched with a lower left guide rail 714 and a lower right guide rail 712 on the lower cylinder 713.

The space enclosed by the third concentric ring 705, the lower-link plunger 706 and the lower-link cylinder 713 forms a second left chamber, the space enclosed by the fourth concentric ring 707, the lower-link plunger 706 and the lower-link cylinder 713 forms a second right chamber, and the volumes of the second left chamber and the second right chamber are changed in a staggered manner along with the reciprocating motion of the plungers.

The two-dimensional pulse width modulation mechanism 11 is characterized in that: the valve comprises a transmission shaft 1101, a null spring 1102, a roller shaft 1103, a left roller assembly 1104, a right roller assembly 1105, a front concentric ring 1106, a first valve core 1108, a first valve sleeve 1107, a rear concentric ring 1109 and a first valve core plug 1110. The fork of the transmission shaft 1101 is matched with the roller assemblies 1103 and 1104 to shift the first valve core 1108 through the roller shaft 1103, so that the first valve core 1108 performs circumferential rotation and axial sliding in the first valve sleeve 1107, the circumferential rotation and the axial sliding of the first valve core 1108 are relatively independent, the front concentric ring 1106 and the rear concentric ring 1109 are fixedly connected to two ends of the first valve sleeve 1107 respectively, and the zero-position spring 1102 is installed between the first valve core 1108 and the transmission shaft 1101 and is in a state of being compressed all the time.

One end of the transmission shaft 1101 is a cylindrical end and is connected with a driven gear 2; the other end of the transmission shaft is in a shape of a door frame and is connected with two U-shaped shifting forks, the shifting fork surfaces are axial incomplete cylindrical surface tracks and are matched with the left roller assembly 1104 and the right roller assembly 1105, so that the first valve core 1108 rotates in the circumferential direction and slides axially; the axial intermediate end surface of the drive shaft 1101 has a circular recess for retaining the null spring 1102.

Two flat end surfaces of the zero position spring 1102 are respectively fixed at a circular groove of the transmission shaft 1101 and a stepped shaft at the left end of the first valve core 1108, and the zero position spring 1102 is in a compressed state in the initial state and the working process, so that the first valve core 1108 is ensured to be at the rightmost end in the initial state, and the zero position of the first valve core is kept.

The roller shaft 1103 is a stepped cylindrical shaft, a shoulder is arranged in the middle of the stepped cylindrical shaft, and the diameter of the middle cylinder is larger than that of the cylinders at the two sides; the middle shoulder shaft is inserted into a cylindrical hole at the left end of the first valve core 1108 and fixedly connected, and the shafts at the two ends are respectively inserted into central circular holes of the left roller assembly 1104 and the right roller assembly 1105 and fixedly connected.

The right roller assembly 1105 and the left roller assembly 1104 are identical in structure and comprise a bearing sleeve 1105.1 and a deep groove ball bearing 1105.2, the outer portion of the bearing sleeve 1105.1 is a spherical surface, the inner portion of the bearing sleeve 1105.1 is a round hole, the two ends of the bearing sleeve are flat end surfaces, an inner hole of the bearing sleeve is sleeved on the outer circle of the deep groove ball bearing and fixedly connected with the outer circle, and the spherical surface of the bearing sleeve 1105.1 is matched with the cylindrical surface of a U-shaped shifting.

The front concentric ring 1106 is circular, two end faces are planes, the outer circle of the front concentric ring 1106 is fixedly connected with the first valve sleeve 1107, and an inner hole is sleeved on the left end shaft of the first valve core 1108.

The back concentric ring 1109 is circular, and both end faces are the plane, and the hole has a ladder hole to provide dodge space for the second circular through-hole b2 of first case 1108, and back concentric ring 1109 excircle links firmly with first valve barrel 1107, and the hole cover is on the axle of first case 1108 right-hand member.

An inner hole of the first valve sleeve 1107 is a central through hole and is matched with the first valve core 1108, and two ends of the first valve sleeve are respectively provided with a front stepped hole and a rear stepped hole which are fixedly connected with a front concentric ring 1106 and a rear concentric ring 1109; the outer circle of the first valve sleeve 1107 is provided with four annular grooves, namely a control oil groove K1, an oil outlet groove A1, an oil inlet groove P1 and an oil return groove T1 from left to right, the control oil groove K1 is uniformly provided with a plurality of identical radial control oil holes K1, the oil outlet groove A1 is uniformly provided with a plurality of identical radial oil outlet holes a1, the oil inlet groove P1 is uniformly provided with a plurality of identical radial rhombic flow distribution windows P, the top point of the rhombic flow distribution windows P is in the same plane and the plane is perpendicular to the axis of the first valve core, and the oil return groove T1 is uniformly provided with a plurality of identical radial oil return holes T1.

A step shaft is arranged at the leftmost end of the first valve core 1108 and used for mounting the zero position spring 1102, and a roller shaft circular through hole is formed in the right side of the step shaft and fixedly connected with the roller shaft 1103 and used for transmitting torque to the first valve core 1108 so as to enable the first valve core to rotate; the first valve core 1108 is provided with three shoulders, namely a first shoulder 1108.1, a second shoulder 1108.2 and a third shoulder 1108.3 in sequence from left to right, a first circular through hole B1 is formed in the radial direction of a first valve core shaft between the first shoulder 1108.1 and the second shoulder 1108.2, a second circular through hole B2 is formed in the radial direction of the first valve core shaft close to the right end face of the third shoulder 1108.3, a central flow passage B1 is axially formed in the center of the first valve core, a central flow passage opening is blocked by a first valve core plug 1110, and the first circular through hole B1 and the second circular through hole B2 are communicated through a first valve core central flow passage B1; two staggered triangular flow distribution windows, namely a left triangular flow distribution window p1 and a right triangular flow distribution window p2, are formed in the second land 1108.2 of the first valve core, and the vertexes of the two staggered triangular flow distribution windows are in the same plane which is perpendicular to the axis of the first valve core.

The spherical surface of the outer circle of the bearing sleeve 1105.1 is in clearance fit with the U-shaped shifting fork of the transmission shaft, the bearing sleeve 1105.1 is in unilateral contact with the shifting fork when stressed, and can rotate forward and backward, the transmission shaft drives the first valve core 1108 to rotate through the left roller assembly 1104, the right roller assembly 1105 and the roller shaft 1103, and the first valve core 1108 slides axially under the action of hydraulic pressure to drive the bearing sleeve 1105.1 to roll axially on the U-shaped shifting fork of the transmission shaft 1101.

The outer circles of the front concentric ring 1106 and the rear concentric ring 1109 are fixedly connected with a front stepped hole and a rear stepped hole of two end surfaces of the first valve sleeve 1107 respectively, the inner hole of the front concentric ring 1106 is sleeved on the shaft of the left end of the first valve core 1108 to form gap sealing, and the inner hole of the rear concentric ring 1109 is sleeved on the shaft of the right end of the first valve core 1108 to form gap sealing.

The first valve core 1108 is rotatably arranged in the first valve sleeve 1107, the front concentric ring 1106 and the first valve core shoulder 1108.1 seal the inner cavity of the first valve sleeve 1107 to form a control cavity K1.1, the control cavity K1.1 is communicated with the control oil groove K1 through the control oil hole K1, and the control oil groove K1 is communicated with control pressure oil; the first valve core first shoulder 1108.1 and the second shoulder 1108.2 seal the inner cavity of the first valve sleeve 1107 to form a high-pressure cavity A1.1, the high-pressure cavity A1.1 is communicated with an oil outlet groove A1 through an oil outlet A1, and is communicated with an oil inlet groove P1 through a rhombic flow distribution window P, the oil inlet groove P1 is communicated with high-pressure oil of a hydraulic pump, and the oil outlet groove A1 is communicated with an oil way of a pump body; the first valve core second shoulder 1108.2 and the third shoulder 1108.3 seal the inner cavity of the first valve sleeve 1107 to form a low-pressure cavity T1.1, the low-pressure cavity T1.1 is communicated with an oil return groove T1 through an oil return hole T1, and the oil return groove T1 is communicated with a low-pressure oil tank; the first valve core third shoulder 1108.3 and the rear concentric ring 1109 seal the first valve sleeve inner cavity to form a feedback cavity A1.2, the feedback cavity A1.2 is communicated with the high pressure cavity A1.1 through the first valve core first circular through hole B1, the central flow passage B and the second circular through hole B2, and the pressures of the two cavities are the same; the first valve housing control oil groove K1, the oil outlet groove a1, the oil inlet groove P1, and the oil return groove T1 are not communicated with each other outside the first valve housing 1107. Two rows of staggered triangular flow distribution windows are formed in the second shoulder 1108.2 of the first valve core, namely a left triangular flow distribution window p1 and a right triangular flow distribution window p2 respectively, the rhombic flow distribution window p of the first valve sleeve is positioned on the motion track of the second shoulder 1108.2 of the first valve core, and the first valve core 1108 axially slides under the action of hydraulic pressure while rotating at a constant speed in the first valve sleeve 1107 so that the ratio of the flow distribution time of the left triangular flow distribution window p1 and the right triangular flow distribution window p2 of the first valve core to the flow distribution time of the rhombic flow distribution window p of the first valve sleeve is changed respectively, thereby changing the flow rate of outlet oil and realizing flow distribution.

In order to explain the flow distribution principle of the two-dimensional pulse width modulation mechanism, the first spool left triangular flow distribution window p1, the right triangular flow distribution window p2 and the first valve sleeve rhombic flow distribution window p are circumferentially expanded and simplified into a schematic diagram, such as fig. 13a, fig. 13b, fig. 13c and fig. 13 d. In the schematic diagram, the left-right linear motion of the first valve core represents circumferential rotation of the first valve core in the structural schematic diagram, and the up-down vertical movement of the first valve core in the schematic diagram represents axial sliding of the first valve core in the structural schematic diagram. In fig. 13a and 13b, P0 is an oil inlet, and is equivalent to an oil inlet groove P1, a0 is an oil outlet, and is equivalent to an oil outlet groove a1, and T0 is an oil return opening, and is equivalent to an oil return groove T1.

The first valve core 1108 can freely rotate and axially slide in the first valve sleeve 1107 in the circumferential direction, and along with the rotation of the first valve core 1108, the left triangular distribution window p1 and the right triangular distribution window p2 of the first valve core 1108 are alternately communicated with the rhombic distribution window p of the first valve sleeve 1107 to periodically change, because the left triangular distribution window p1 and the right triangular distribution window p2 of the first valve core 1108 are in a large number with a large valve port area gradient, the influence of the valve port opening degree on the flow passing through the valve port is small, the flow passing through the valve port can be considered as a quantity which is irrelevant to the valve port opening degree and only relevant to the valve port opening time, namely the ratio of the time required by the left triangular distribution window p1 and the right triangular distribution window p2 of the first valve core 1108 to alternately sweep through the rhombic distribution window p of the first valve sleeve 1107 in any period to the total time respectively, so as to distribute the flow, and the flow distribution is carried out on the oil outlet flow and the oil return flow according to the proportion.

As shown in fig. 13c and 13d, setting the flow Q of the oil inlet P0 on the ordinate, the time T on the abscissa, and the time Δ T1 required by the triangular flow distribution window P1 on the left side of the first valve core 1108 to sweep through the rhombic flow distribution window P of the first valve sleeve 1107 within any cycle time Δ T, the time Δ T2 required by the triangular flow distribution window P2 on the right side of the first valve core 1108 to sweep through the rhombic flow distribution window P of the first valve sleeve 1107, the flow of the oil outlet a0 is Q · Δ T1/Δ T, and the flow of the oil return port T0 is Q · Δ T2/Δ T. As can be seen by comparing fig. 13c and 13d, the axial sliding of the first spool changes the ratio of Δ t1 and Δ t2, thereby changing the flow of oil into the hydraulic system, and therefore, the manner in which the system flow is regulated by this structure can be considered to be pulse width modulation controlled by the position of the first spool.

The two-dimensional pressure servo valve 12 is characterized in that: the displacement sensor module is matched with the valve body module, and the electro-mechanical converter module is matched with the valve body module; the displacement sensor module monitors the displacement of the 2D piston in the valve body module in real time and the torque motor electric signal of the electric-mechanical converter module to form closed-loop feedback.

The valve body module comprises a second valve core 1203, a second valve core housing 1204, a 2D piston 1212, a left gasket 1205, a right gasket 1207, a concentric ring 1208, a pressure regulating spring 1206, a second valve sleeve 1213, a valve sleeve plug 1201 and a positioning pin 1202. The second valve spool 1203 is arranged in an inner hole of a second valve spool housing 1204, the 2D piston 1212 is arranged on the right side of a second valve sleeve 1213, the valve sleeve plug 1201 is fixedly connected to the left end portion of the second valve sleeve 1213 through a positioning pin 1202, and the second valve spool housing 1204 is positioned through the valve sleeve plug 1201 and fixed on the left side of the second valve sleeve 1213. The right-hand member at first valve core 1203 is connected to left gasket 1205, and right gasket 1207 is connected at the left end of 2D piston 1212, is connected with pressure regulating spring 1206 between left gasket 1205 and the right gasket 1207, and the 2D piston 1212 right side is provided with concentric ring 1208.

The second valve sleeve 1213 is provided with three annular grooves, which are an oil inlet groove P2, an oil outlet groove a2 and an oil return groove T2 from left to right, wherein the oil inlet groove P2 is uniformly provided with a plurality of identical radial oil inlet holes P3, the oil outlet groove a2 is uniformly provided with a plurality of identical radial oil outlet holes a2, and the oil return groove T2 is uniformly provided with a plurality of identical radial oil return holes T2. The right inner hole wall of the second valve sleeve 1213 is provided with a pair of damping chutes which are matched with the high-low pressure grooves c1 and c2 on the shoulder 1212.1 of the 2D piston 1212. And O-shaped sealing rings are arranged on two sides of each oil port of the second valve sleeve, so that the local sealing of the servo valve is ensured.

The 2D piston 1212 is mounted in a second housing 1213, with both directions of movement, circumferential rotation and axial sliding, in the second housing 1213; a shoulder 1212.1 is arranged at the left end of the 2D piston 1212, a pair of high-pressure grooves c1 and a pair of low-pressure grooves c2 are arranged on the shoulder in a matched mode and matched with a pair of damping chutes formed in the inner hole wall of the second valve sleeve 1213, the pair of high-pressure grooves c1 are communicated with the oil inlet p3, the pair of low-pressure grooves c2 are communicated with the oil return hole t2 through a central flow passage B3, a shoulder 1212.1 and a concentric ring 1208 of the 2D piston are sealed with the second valve sleeve 1213 to form a left sensitive cavity D1 and a right sensitive cavity D2, a pair of high-pressure grooves c1 and a pair of low-pressure grooves c2 on a shoulder 1212.1 of the 2D piston are intersected with the pair of damping chutes to form four tiny opening areas which are connected in series to form a hydraulic resistance half bridge, pressure change of the left sensitive cavity D1 is controlled, the right sensitive cavity D2 is communicated with the oil inlet p3, pressures of the left sensitive cavity D1 and the right sensitive cavity D2.

The second valve core shell 1204 is uniformly provided with 4 same radial through holes e1 on a left end shoulder 1204.1 and is communicated with an oil inlet hole p 3; the annular groove on the right side of the second valve core shell is uniformly provided with 4 same radial through holes e2 which are communicated with the oil outlet a 2. The second spool housing 1204 cooperates with the valve sleeve plug 1201 to form a control chamber K3.

The second valve spool 1203 is provided with a first shoulder 1203.1 and a second shoulder 1203.2, which cooperate with the first valve spool housing 1204 to change the opening of the oil port when the second valve spool 1203 moves axially. The left end surface S3 of the second valve core is a disk-shaped structure, and when the second valve core 1203 moves left and right, a squeeze film is formed between the disk-shaped structure of the second valve core and the control chamber K3, which has the functions of introducing a squeeze film damping coefficient, increasing the viscous damping of the system, and improving the damping ratio to make the system more stable. The right side of the first shoulder 1203.1 of the second valve core is provided with a through hole e3, which is communicated with the oil outlet a2 and is communicated with the control cavity K3 through a central flow passage B2.

When the 2D piston 1212 rotates clockwise (looking to the left from the side of the transmission), the intersection area of the high pressure groove c1 and the damping chute decreases, the intersection area of the low pressure groove c2 and the damping chute increases, the pressure in the left sensitive chamber D1 decreases, the pressure in the right sensitive chamber D2 does not change, and the 2D piston 1212 moves to the left. In the process of left movement, the intersection area of the high-pressure groove c1 and the damping chute is increased, the intersection area of the low-pressure groove c1 and the damping chute is reduced, the pressure of the left sensitive cavity D1 is gradually increased and is finally equal to the pressure of the right sensitive cavity D2, and the 2D piston is stabilized at a certain position. The 2D piston 1212 moves left to generate a left force and transmits the force to the second valve core 1203 through the pressure regulating spring 1206, the force on the right end of the second valve core 1203 is increased, the original hydraulic pressure balance fails, so that the second valve core 1203 moves left, the second valve core 1203 moves left to increase the valve port opening, the pressure of the oil outlet a2 is increased, the oil outlet a2 is communicated with the control cavity K3, the hydraulic pressure on the left end surface S3 of the second valve core is increased, when the hydraulic pressure on the right is smaller than the pressure regulating spring force, the second valve core 1203 continues to move left, the valve port opening continues to increase, and the output pressure continues to increase; when the hydraulic force to the right equals the pressure regulator spring force, the second spool 1203 stops moving to the left and stabilizes at a certain position while keeping the outlet pressure substantially constant.

The electric-mechanical converter module adopts a torque motor 1210 and comprises a motor housing 1209, a shell 1210.1, an armature 1210.2, a permanent magnet 1210.3, a magnetizer 1210.4, a clamping piece 1210.5, a coil 1210.6, a spring 1210.7, a spring rod 1210.8, a spring seat 1210.10, a limiting rod 1210.9 and a connecting plate 1210.11, wherein the shell 1210.1 and the motor housing 1209 are both connected with the connecting plate 1210.11, the shell 1210.1 is fixedly connected with the connecting plate 1210.11 through screws, one end of the spring 1210.7 is connected with the spring rod 1210.8, and the other end of the spring 1210.7 is connected with the spring seat 1210.10 fixed on the shell. The electro-mechanical converter module is connected to the pump body 8 by a connection plate 1210.11. The two-dimensional pressure servo valve 12 uses a dry torque motor so O-rings are also placed in the motor housing 1209 and web 1210.11 to seal the output member against oil entering the space around the armature 1210.2, coil 1210.6 and permanent magnet 1210.3.

The electro-mechanical converter module includes a magnetic circuit portion, a transmission portion, and a motor housing. The magnetic circuit part consists of 2 coils 1210.6, 2 magnetizers 1210.4, 1 armature 1210.2 and 2 permanent magnets 1210.3. When the coil is not electrified, the armature keeps balance 1210.2; energization of coil 1210.6 creates a magnetic path that disrupts the previous equilibrium state and deflects armature 1210.2. The transmission part comprises a spring 1210.7, a spring seat 1210.10, a spring rod 1210.8 and a limiting rod 1210.9. While housing 1210.1 and catch 1210.5 are used to secure and position the parts. Deflection of armature 1210.2 causes 2D piston 1212 and spring lever 1210.8 to rotate. Spring 1210.7 is connected at one end to spring rod 1210.8 and at the other end to spring seat 1210.10, which is attached to the housing, so that the rotational movement of spring rod 1210.8 is effectively transferred to spring 1210.7, ensuring that in abnormal situations, spring 1210.7 automatically returns to zero, thereby returning armature 1210.2 and 2D piston 1212 to their initial positions.

The displacement sensor (LVDT sensor) module comprises an LVDT connecting rod 1210.12 and an LVDT sensor (consisting of an iron core 1210.13 and a coil framework 1210.14), the LVDT sensor is matched with the shell 1210.1 and an arc of the clamping piece 1210.5, the clamping piece 1210.5 is pressed on the LVDT sensor through screws to realize the fixation of the LVDT sensor, the spring rod 1210.8 and the LVDT connecting rod 1210.12 are connected in a mutually perpendicular mode, the LVDT connecting rod 1210.12 is connected with the iron core 1210.13, the iron core 1210.13 and the LVDT sensor are in clearance fit, and the inner hole of the LVDT sensor can move directly. The LVDT sensor is connected to the 2D piston 1212 of the valve body module by a threaded connecting rod.

In the working process of the torque motor, the armature 1210.2 drives the spring rod 1210.8 and the 2D piston 1212 to rotate, the 2D piston moves linearly by combining the 2D servo spiral theorem, and simultaneously drives the spring rod 1210.8 and the iron core 1210.13 to move linearly, and the displacement of the iron core 1210.13 is transmitted to a controller in the form of an electric signal by combining the LVDT principle, so that the closed-loop control of the displacement of the 2D piston is realized.

A plurality of oil paths are arranged in the pump body, and an oil inlet groove P1 of the two-dimensional pulse width modulation mechanism is communicated with an oil outlet K of the duplex plunger pump through the oil paths; an oil outlet tank A1 of the two-dimensional pulse width modulation mechanism is communicated with an oil outlet M4 of the pump body; an oil return tank T1 of the two-dimensional pulse width modulation mechanism is communicated with a system oil tank; a control oil groove A1 of the two-dimensional pulse width modulation mechanism is communicated with an oil outlet groove A2 of the two-dimensional pressure servo valve; an oil inlet groove P1 of the two-dimensional pulse width modulation mechanism is communicated with an oil inlet groove P2 of the two-dimensional pressure servo valve; the oil return groove T1 of the two-dimensional pulse width modulation mechanism is communicated with an oil return groove T2 of the two-dimensional pressure servo valve.

The working principle of the example is as follows:

when an external motor is started, the upper-linkage plunger 504 is driven by a motor coupler to rotate at a constant speed, due to the matched connection of the upper-linkage right-end structural shaft 507 and the lower-linkage left-end structural shaft 701, the upper-linkage plunger and the 504 lower-linkage plunger 706 rotate circumferentially together, the large roller sets of the upper-linkage left structural shaft 501 and the lower-linkage left structural shaft 701 are arranged on the corresponding upper-linkage left rail 510 and lower-linkage left rail 714, the large roller sets of the upper-linkage right structural shaft 507 and the lower-linkage right structural shaft 709 are arranged on the corresponding upper-linkage right rail 508 and lower-linkage right rail 712, and when each large roller set rotates, the large roller sets are constrained by the curved surface rails and must do reciprocating motion in the axial direction. Therefore, the upper plunger 504 and the lower plunger 706 can axially and continuously reciprocate along with the continuous rolling of the large roller groups on the corresponding left and right equal deceleration curved surface tracks.

Looking first at the upper pump core 5, the volumes of the first left chamber and the second right chamber change regularly as the upper plunger 504 reciprocates. When the upper plunger 504 moves axially from the leftmost end to the rightmost end, the first left chamber volume gradually increases and the first right chamber volume gradually decreases; similarly, when the upper connecting plunger 504 moves axially from the rightmost end to the leftmost end, the first right chamber volume gradually increases, and the first left chamber volume gradually decreases. The lower pump core 7 and the upper pump core 5 move in the same way.

When the duplex plunger pump works, the flow distribution groove on the plunger is communicated with the window on the cylinder body, the cavity with gradually-increased volume absorbs oil from the oil tank through the communicated flow distribution groove and the window, the cavity with gradually-decreased volume discharges oil outwards through the communicated flow distribution groove and the window, and the plunger reciprocates to enable the volume of the left cavity and the right cavity to change continuously in a staggered manner, so that continuous oil suction and discharge are realized.

Fig. 6 is a schematic diagram of the working principle of the two-dimensional duplex plunger pump (taking the above-mentioned duplex pump core as an example). The upper plunger rotates clockwise (viewed from left to right), and a, b, c and d are rectangular distributing grooves on the upper plunger. e. f, g and h are flow distribution windows of the upper cylinder body, e and g are oil absorption windows, and f and h are oil discharge windows. When the upper plunger moves to the leftmost end, the rectangular distributing grooves a, b, c and d are not communicated with the windows e, f, g and h as shown in fig. 6 a. When the upper plunger rotates and starts to move towards the right end, as shown in fig. 6b, the rectangular distributing grooves a, b, c and d are respectively communicated with the windows e, f, g and h. The first left chamber with the gradually-increased cavity absorbs oil from the oil tank through the communication channels a-e and c-g due to self-absorption; the first right chamber with gradually reduced volume extrudes the oil in the cavity through the communication channels b-f and d-h. When the upper plunger moves to the rightmost end, the rectangular distributing grooves a, b, c and d on the upper plunger and the windows e, f, g and h are not communicated with each other at the moment, as shown in fig. 6 c. When the upper connecting plunger continues to rotate, the upper connecting plunger starts to move leftwards, and the first right chamber starts to suck oil from the oil tank through the communication channels b-g and d-e; the first left chamber extrudes oil through communication channels a-f and c-h, and oil discharged by two cylinder bodies of the duplex plunger pump is communicated on the pump body and discharged from the same oil outlet.

The oil discharged by the duplex plunger pump 6 is introduced into the pressure servo variable mechanism 10 through a pump body liquid channel. Due to the gear transmission, the pressure servo variable mechanism 10 and the double-plunger pump 6 start to work simultaneously.

The pressure servo variable mechanism 10 has two working states of constant pressure variable and pressure servo.

In the working process of the constant pressure variable state, the two-dimensional pressure servo valve 12 does not receive a given signal or a system given feedback signal, the system pressure is unchanged, and if the system flow changes, the system pressure also slightly changes accordingly. When the required flow of the system is increased, the pressure of the system is reduced, that is, the pressure of the feedback cavity a1.2 of the two-dimensional pulse width modulation mechanism is reduced, the balance state of the left end and the right end of the first valve core 1108 of the two-dimensional pulse width modulation mechanism is broken, the resultant force of the left end S1 of the first valve core is greater than the resultant force of the right end S2, so that the first valve core 1108 of the two-dimensional pulse width modulation mechanism moves rightwards, the opening degree of the oil inlet P1 is increased, the opening time is prolonged, more flow flows into the system to supply energy to the system, the pressure of the feedback cavity a1.2 is increased. On the contrary, when the required flow of the system is reduced, the system pressure is increased, that is, the pressure of the feedback cavity a1.2 is increased, the balance state of the left end and the right end of the first valve core is broken, the resultant force of the left end S1 of the first valve core is smaller than the resultant force of the right end S2, the first valve core 1108 moves leftwards, the opening degree of the oil return port T1 is increased, the opening time is prolonged, more flow flows flow back to the oil tank to reduce the oil supply amount in the system, and the pressure of the feedback cavity a1.2 is reduced to maintain the original force balance state.

When the two-dimensional pressure servo valve 12 is in a pressure servo state, the two-dimensional pressure servo valve 12 receives a given signal or a system given feedback signal, the torque motor 1210 drives the 2D piston 1212 to move, and axially outputs a certain displacement, and transmits force to the second valve core 1203 through a spring, hydraulic pressure applied to the second valve core 1203 is unbalanced and axially moves, and the opening of a valve port changes, so that output pressure changes until hydraulic pressure applied to the left end surface S3 of the second valve core and the spring force are balanced again, outlet pressure of the servo valve is substantially a fixed value, and system pressure is constant again. An oil outlet A2 of the two-dimensional pressure servo valve is communicated with a control cavity K1.1 of the two-dimensional pulse width modulation mechanism, the pressure of an oil outlet A2 of the two-dimensional pressure servo valve changes, the original balance state of a first valve core 1108 of the two-dimensional pulse width modulation mechanism is broken through, the first valve core 1108 moves axially, the ratio of the time required for the first valve core to alternately sweep a rhombic flow distribution window p of a first valve sleeve to the total time is correspondingly changed respectively through a left triangular flow distribution window p1 and a right triangular flow distribution window p2 of the first valve core, the oil outlet flow and the oil return flow are correspondingly changed, the flow entering the system is correspondingly changed, the pressure of a feedback cavity A1.2 is correspondingly changed, and the first valve core 1108 reaches a new balance state until the axial resultant force of the first valve core 1108 is balanced again, and the pressure of the system.

When the system pressure needs to be reduced, the pressure difference between the 2D piston sensitive cavity D1 and the pressure cavity D2 is reduced, the second valve core 1203 moves rightwards to reduce the opening of the valve port, the pressure oil port p3 is communicated with the control cavity K3, the hydraulic pressure of the left end surface S3 of the second valve core to the right is reduced, and the force is balanced with the pressure regulating spring force. When the output pressure is greater than the set pressure value, the hydraulic pressure on the left end surface S3 of the second valve core is greater than the pressure regulating spring force, the second valve core 1203 continues to move to the right, the opening of the valve port continues to decrease, the output pressure continues to decrease, when the output pressure reaches the set value of the valve, the hydraulic pressure on the second valve core 1203 reaches balance again, at the moment, the opening of the valve port decreases, the pressure of the oil outlet is reduced, and the pressure of the oil outlet is kept to be a fixed value basically. The pressure of an oil outlet A2 of the two-dimensional pressure servo valve is reduced, so that the pressure of a control cavity K1.1 of the two-dimensional pulse width modulation mechanism is reduced, the resultant force of S1 at the left end of the first valve core is smaller than the resultant force of S2 at the right end, the first valve core 1108 moves leftwards, the opening degree of a valve port of the oil inlet p1 is reduced (till the valve port is completely closed), the pressure of the oil outlet A1 is reduced along with the loss of oil in the system, and the first valve core 1108 reaches a new balance state until the resultant forces at the two ends of the first valve core 1108 are equal again, so that the pressure.

Conversely, when the system pressure needs to be increased, the pressure difference between the 2D piston sensing chamber D1 and the pressure chamber D2 is increased, the second valve spool 1203 moves leftwards to increase the valve port opening degree, the hydraulic pressure on the left end surface S3 of the second valve spool increases rightwards, and the force is balanced with the pressure regulating spring force. When the output pressure is smaller than the set pressure value, the hydraulic pressure on the left end surface S3 of the second valve core is smaller than the pressure regulating spring force, the second valve core 1203 continues to move leftwards, the opening degree of the valve port continues to increase, and the output pressure continues to increase; when the output pressure reaches the set pressure value of the valve, the hydraulic pressure applied to the first valve core 1203 is balanced again, at the moment, the opening degree of the valve port is increased, the pressure of the oil outlet is increased, and the pressure of the oil outlet A2 is kept to be basically a fixed value. The pressure of an oil outlet A2 of the two-dimensional pressure servo valve is increased, so that the pressure of a control cavity K1.1 of the two-dimensional pulse width modulation mechanism is increased, the resultant force of S1 at the left end of the first valve core is larger than the resultant force of S2 at the right end, the first valve core 1108 moves rightwards, the opening degree of a valve port of an oil return port p2 is reduced (till the valve port is completely closed), the pressure of the oil outlet A1 is increased along with the inflow of a large amount of oil in the system, and the first valve core 1108 reaches a new balance state until the resultant forces at the two ends of the first valve core 1108 are equal again.

The embodiments described in this specification are merely illustrative of implementations of the inventive concept and the scope of the present invention should not be considered limited to the specific forms set forth in the embodiments but rather by the equivalents thereof as may occur to those skilled in the art upon consideration of the present inventive concept.