阅读说明：本技术 用于较高频响要求且安装空间受限的液压系统液压缸结构 (Hydraulic cylinder structure of hydraulic system with higher frequency response requirement and limited installation space ) 是由 周华 罗贵福 于瑞 付波 于 2019-09-03 设计创作，主要内容包括：本发明公开了一种用于较高频响要求且安装空间受限的液压系统液压缸结构。采用液压缸与阀块集成方式,将液压缸的缸筒与阀块一体化,可消除液压缸与阀块的连接、定位和端面配合问题,并能灵活选配确定性能的伺服阀。采用直线轴承与活塞杆之间以滚动副形式接触。本发明可消除活塞杆与轴承之间的滑动摩擦力,降低液压缸的启动压力,从而提高液压系统运动频率,能满足相对于传统接触型支承方式更高的频响要求,液压缸与阀块集成,减小了液压缸体积,使得液压缸适用于空间受限的场合,相对于液压缸与伺服阀集成,伺服阀性能可选,实现了成本与性能兼顾。(The invention discloses a hydraulic cylinder structure of a hydraulic system, which is used for meeting high frequency response requirements and has a limited installation space. The integration mode of the hydraulic cylinder and the valve block is adopted, the cylinder barrel of the hydraulic cylinder is integrated with the valve block, the problems of connection, positioning and end face matching of the hydraulic cylinder and the valve block can be solved, and the servo valve with definite performance can be flexibly selected and matched. The linear bearing is in contact with the piston rod in a rolling pair mode. The invention can eliminate the sliding friction force between the piston rod and the bearing, reduce the starting pressure of the hydraulic cylinder, thereby improving the motion frequency of the hydraulic system, and meeting the requirement of higher frequency response compared with the traditional contact type supporting mode.)

1. The utility model provides a hydraulic system pneumatic cylinder structure that is used for higher frequency response requirement and installation space to be restricted which characterized in that: comprises a piston block (1.1), a piston rod (1.2), a bearing sleeve (8), an end cover (10) and a cylinder barrel (12); annular end covers (10) are mounted at two ends of a cylinder barrel (12), the cylinder barrel (12) and the end covers (10) are sealed through first sealing rings (13), two ends of a piston block (1.1) are coaxially and fixedly connected with piston rods (1.2), the piston block (1.1) is arranged in the cylinder barrel (12), the piston rods (1.2) are arranged in the end covers (10), the piston blocks (1.1) and the piston rods (1.2) form piston bodies which axially move in an inner cavity formed between the cylinder barrel (12) and the end covers (10), and the inner cavity of the cylinder barrel (12) is filled with oil; a bearing sleeve (8) is sleeved between the piston rod (1.2) and the end cover (10), the bearing sleeve (8) and the end cover (10) are sealed through a second sealing ring (14), a dustproof ring (2), a steckel seal (3) and a linear bearing (9) are sequentially arranged on the inner circumferential surface of the bearing sleeve (8) from the outer end to the inner end, the bearing sleeve (8) and the piston rod (1.2) are in sealed dustproof connection through the dustproof ring (2) and the steckel seal (3), and the bearing sleeve (8) and the piston rod (1.2) are in linear rolling connection through the linear bearing (9); the linear bearing (9) is a linear bearing with balls arranged in the circulating closed loop raceway, and one end close to the inner cavity is communicated with the inner cavity; a piston rod (1.2) at one end of a piston block (1.1) is used as an output end of the hydraulic cylinder, a central blind hole is formed in the end face of the piston rod (1.2) at the other end of the piston block (1.1), a threaded section at the inner end of a displacement sensor (21) is screwed into a threaded hole formed in the bottom surface of the central blind hole and is positioned and screwed through a nut (22), the outer end of the displacement sensor (21) is fixedly connected to the hole end face of the central blind hole of the piston rod (1.2) at the other end through a displacement sensor support (19), and an acceleration sensor (16) is screwed into the upper side of the hole end face of the central blind hole of the piston rod (1.2; one side of the cylinder barrel (12) radially protrudes out of the end cover (10) to form a valve part, two axial side faces of the valve part are provided with an oil inlet (24) and an oil outlet (25), the radial outer surface of the valve part is provided with four cylinder holes which are respectively a P hole, a T hole, an A hole and a B hole, the inner surface of the cylinder barrel (12) corresponding to the valve part in the radial direction is provided with two inner cavity oil ports, the inner cavity oil ports are communicated with an inner cavity formed between the cylinder barrel (12) and the end cover (10), the two inner cavity oil ports are respectively positioned at two axial ends of the inner cavity, the P hole and the oil inlet (24) are communicated through an inner pipeline of the cylinder barrel (12), the oil inlet (24) is connected to a high-pressure oil source, the T hole and the oil outlet (25) are communicated through an inner pipeline of the cylinder barrel (12), the oil outlet (25) is connected to an oil, the radial outer surface of the valve part is provided with a servo valve, the servo valve is provided with four valve ports of a P port, a T port, an A port and a B port, the P port, the T port, the A port and the B port are respectively communicated with a P hole, a T hole, an A hole and a B hole of a cylinder hole of the valve part of the cylinder barrel (12), the oil hydraulic pressure of inner cavities at two ends of the piston block (1.1) is controlled and adjusted through the valve ports of the servo valve, the piston block (1.1) is driven to axially move, and the output motion of the hydraulic cylinder is realized.

2. The hydraulic cylinder structure of claim 1, wherein the hydraulic cylinder structure is used for a hydraulic system with high frequency response requirement and limited installation space, and is characterized in that: the end cover (10) is fixedly mounted at the end part of the cylinder barrel (12) through a second bolt (6) and a second gasket (7).

3. The hydraulic cylinder structure of claim 1, wherein the hydraulic cylinder structure is used for a hydraulic system with high frequency response requirement and limited installation space, and is characterized in that: the bearing sleeve (8) is provided with an outer flange, and the outer flange is fixedly mounted on the outer end face of the end cover (10) through a first bolt (4) and a first gasket (5) so that the bearing sleeve (8) is fixedly connected with the end cover (10).

4. The hydraulic cylinder structure of claim 1, wherein the hydraulic cylinder structure is used for a hydraulic system with high frequency response requirement and limited installation space, and is characterized in that: the piston block (1.1) and the piston rod (1.2) are integrally formed.

5. The hydraulic cylinder structure of claim 1, wherein the hydraulic cylinder structure is used for a hydraulic system with high frequency response requirement and limited installation space, and is characterized in that: the displacement sensor clamping plate (20) clamps and installs the outer end part of the displacement sensor (21) on the displacement sensor bracket (19), the two ends of the displacement sensor bracket (19) are fixedly connected to the displacement sensor clamping plate (20) through a third bolt (17), and the outer end part of the displacement sensor (21) is clamped between the middle part of the displacement sensor bracket (19) and the displacement sensor clamping plate (20).

6. The hydraulic cylinder structure of claim 1, wherein the hydraulic cylinder structure is used for a hydraulic system with high frequency response requirement and limited installation space, and is characterized in that: the displacement sensor (21) detects the axial displacement of the piston body, and the acceleration sensor (16) detects the axial acceleration of the piston body.

Technical Field

The invention relates to a hydraulic cylinder, in particular to a hydraulic cylinder used in a hydraulic system with high frequency response requirements and limited installation space.

Background

The hydraulic cylinder is a device for converting hydraulic pressure energy into linear motion of a piston rod, and is an important actuating element in a hydraulic system. The hydraulic system has the characteristic of high power density and is usually used in occasions with large load force, but the movement frequency of the hydraulic system is low, and the hydraulic system cannot meet the working occasions with high frequency requirements (such as more than 200-300 Hz). The cylinder response frequency and the servo valve response frequency are two important factors that limit the frequency rise of the hydraulic system.

Factors influencing the response frequency of the hydraulic cylinder include the natural frequency of the hydraulic cylinder, the starting pressure, internal and external leakage and the like. Wherein the larger the starting pressure, the lower the response frequency of the hydraulic cylinder. The starting pressure of the hydraulic cylinder is closely related to the friction force, and the smaller the friction force of the hydraulic cylinder is, the smaller the starting pressure is. The main reason for the friction of hydraulic cylinders is the guidance and support of the piston and piston rod.

Existing cylinder support methods are classified into contact type supports and non-contact type supports. In the contact type bearing, the guide ring and the piston rod relatively move in a moving pair mode, the piston rod and the guide ring relatively slide, sliding friction exists, and the generated friction force is large. Non-contact type bearings are typically hydrostatic bearings. The static pressure supporting mode can almost completely eliminate sliding friction force, but an independent oil supply way needs to be designed, the complexity of the system is increased, a certain external space is occupied, and the static pressure supporting mode is not suitable for working occasions with limited installation space.

The rolling friction support mode is adopted, so that the support friction force of the hydraulic cylinder can be effectively reduced, and the design of an external oil circuit is avoided, so that the space limitation requirement is met. The prior Chinese patent with the publication number of CN102175387A discloses a rolling friction hydraulic cylinder which is used for a hydraulic force standard machine to reduce the starting pressure of the system. However, this patent only mentions rolling friction cylinders and does not teach how to implement such cylinders. Fig. 4 is a partial drawing of the rolling friction cylinder of this patent, noting that the bearing portion cannot simply replace the guide ring with balls, and that such replacement will eventually still be a sliding friction function.

Generally, a hydraulic cylinder is connected with a servo valve through a valve block, and the valve block is connected with the hydraulic cylinder through a bolt, so that the size of the hydraulic cylinder is increased. In order to reduce the volume of the hydraulic system, a cylinder valve integrated element is used at present. The invention patent of China with the publication number of CN108708885A adopts the reverse thinking of integrating with a cylinder valve, discloses a valve cylinder integrated element, can better adapt to the requirements of integration and generalization, and has smaller system volume. Cylinder valve integration or valve cylinder integration both add element manufacturing difficulties and neither can be combined with the best current valve (or cylinder) to achieve an optimal combination of valve and cylinder.

Disclosure of Invention

Aiming at the defects in the background technology, the invention aims to provide the hydraulic cylinder adopting the linear bearing, which can improve the response frequency of a hydraulic system to a certain extent, reduce the volume of an execution element of the hydraulic system, has a certain integration level, can be flexibly combined with servo valves with various performance levels at present, and realizes the optimal combination of the performance and the cost of the hydraulic system.

In order to achieve the purpose, the specific technical scheme of the invention is as follows:

the invention comprises a piston block, a piston rod, a bearing sleeve, an end cover and a cylinder barrel; the two ends of the cylinder barrel are respectively provided with an annular end cover, the cylinder barrel and the end covers are sealed through a first sealing ring, the two ends of the piston block are coaxially and fixedly connected with a piston rod, the piston block is arranged in the cylinder barrel, the piston rod is arranged in the end covers, the piston block and the piston rod form a piston body which axially moves in an inner cavity formed between the cylinder barrel and the end covers, and the inner cavity of the cylinder barrel is filled with oil; a bearing sleeve is sleeved between the piston rod and the end cover, the bearing sleeve and the end cover are sealed through a second sealing ring, a dustproof ring, a Stent seal and a linear bearing are sequentially arranged on the inner circumferential surface of the bearing sleeve from the outer end to the inner end, the bearing sleeve and the piston rod are in sealed dustproof connection through the dustproof ring and the Stent seal, and the bearing sleeve and the piston rod are in linear rolling connection through the linear bearing; the linear bearing is a linear bearing with balls arranged in the circulating closed loop raceway, and one end close to the inner cavity is communicated with the inner cavity; a piston rod at one end of the piston block is used as an output end of the hydraulic cylinder, a central blind hole is formed in the end face of the piston rod at the other end of the piston block, a threaded section at the inner end of the displacement sensor is screwed into a threaded hole formed in the bottom surface of the central blind hole and is positioned and screwed through a nut, the outer end of the displacement sensor is fixedly connected to the hole end face of the central blind hole of the piston rod at the other end through a displacement sensor support, and the acceleration sensor is screwed into the upper side of the hole end face of the; one side of the cylinder barrel radially protrudes out of the end cover to form a valve part, two axial side faces of the valve part are provided with an oil inlet and an oil outlet, the radial outer surface of the valve part is provided with four cylinder holes which are respectively a P hole, a T hole, an A hole and a B hole, the inner surface of the cylinder barrel corresponding to the radial direction of the valve part is provided with two inner cavity oil ports, the inner cavity oil ports are communicated with an inner cavity formed between the cylinder barrel and the end cover, the two inner cavity oil ports are respectively positioned at two axial ends of the inner cavity, the P hole is communicated with the oil inlet through an inner pipeline of the cylinder barrel, the oil inlet is connected with a high-pressure oil source, the T hole is communicated with the oil outlet through the inner pipeline of the cylinder barrel, the oil outlet is connected with an oil tank (a low-pressure oil source) through a pipeline, the A hole and the B hole are, the port P, the port T, the port A and the port B are respectively communicated with the port P, the port T, the port A and the port B of the cylinder hole of the cylinder barrel valve part, and the oil hydraulic pressure of the inner cavities at the two ends of the piston block is controlled and adjusted through the valve port of the servo valve to drive the piston block to axially move, so that the output motion of the hydraulic cylinder is realized.

The end cover is fixedly arranged at the end part of the cylinder barrel through a second bolt and a second gasket.

The bearing sleeve is provided with an outer flange, and the outer flange is fixedly mounted on the outer end face of the end cover through a first bolt and a first gasket, so that the bearing sleeve is fixedly connected with the end cover.

The piston block and the piston rod are integrally formed.

The displacement sensor bracket is characterized in that the outer end part of the displacement sensor is clamped and installed on the displacement sensor bracket by the displacement sensor clamping plate, the two ends of the displacement sensor bracket are fixedly connected to the displacement sensor clamping plate by third bolts, and the outer end part of the displacement sensor is clamped between the middle part of the displacement sensor bracket and the displacement sensor clamping plate.

The displacement sensor detects the axial displacement of the piston body, and the acceleration sensor detects the axial acceleration of the piston body.

The invention adopts the integration mode of the hydraulic cylinder and the valve block, integrates the cylinder barrel (outside the dotted line around the cylinder barrel 12 shown in figure 1) of the hydraulic cylinder and the valve block (inside the dotted line around the cylinder barrel 12 shown in figure 1), can eliminate the problems of connection, positioning and end face matching of the hydraulic cylinder and the valve block, simplifies the assembly, and can flexibly select and match a servo valve with definite performance. The linear bearing is in contact with the piston rod in a rolling pair mode, so that sliding friction between the piston rod and the bearing is eliminated, the starting pressure of the hydraulic cylinder is reduced, the design of an external oil circuit is avoided, the movement frequency of a hydraulic system is improved, and meanwhile, the space occupied by equipment is reduced.

The invention has the beneficial effects that:

the invention provides a specific structure of a bearing mode in a rolling friction mode. The linear bearing is in contact with the piston rod in a rolling pair mode, so that sliding friction between the piston rod and the bearing can be eliminated, the starting pressure of the hydraulic cylinder is reduced, and the design of an external oil circuit is avoided, so that the movement frequency of a hydraulic system is improved, and the space occupied by equipment is reduced.

The invention adopts the mode of integrating the cylinder barrel and the valve block, avoids the installation design of the hydraulic cylinder and the valve block, thereby reducing the volume of the hydraulic cylinder, enabling the hydraulic cylinder to be suitable for occasions with limited space, and simultaneously, selecting a proper servo valve to be combined with the hydraulic cylinder to realize cost and performance consideration.

The invention can meet the higher frequency response requirement compared with the traditional contact type supporting mode, has certain integration level, and can be flexibly combined with servo valves with various performance levels at present, so that the performance and the cost of a hydraulic system are optimally combined.

Drawings

Fig. 1 is a front view of the structure of the present invention.

Fig. 2 is a top view of the structure of the present invention.

Fig. 3 is a right side view of the inventive structure.

Fig. 4 is a structural view of a conventional hydraulic cylinder.

Fig. 5 is a partial view of a linear bearing installation.

Fig. 6 is a schematic diagram of a three-dimensional structure of a linear bearing.

In the figure: the device comprises a piston block 1.1, a piston rod 1.2, a dust ring 2, a step seal 3, a first bolt 4, a first gasket 5, a second bolt 6, a second gasket 7, a bearing sleeve 8, a linear bearing 9, an end cover 10, a ball expansion type plug 11, a cylinder barrel 12, a first sealing ring 13, a second sealing ring 14, a stud 15, an acceleration sensor 16, a third bolt 17, a third gasket 18, a displacement sensor support 19, a displacement sensor clamp plate 20, a displacement sensor 21, a nut 22, a buffer sleeve 23, an oil inlet 24 and an oil outlet 25.

Detailed Description

The invention will be further described with reference to the accompanying drawings.

As shown in fig. 1, the embodiment of the present invention includes a piston block 1.1, a piston rod 1.2, a bearing sleeve 8, an end cover 10, and a cylinder 12; annular end covers 10 are installed at two ends of a cylinder 12, the end covers 10 are fixedly installed at the end portions of the cylinder 12 through second bolts 6 and second gaskets 7, a first sealing ring 13 is arranged between the cylinder 12 and the end covers 10 and sealed through the first sealing ring 13, piston rods 1.2 are fixedly connected to two ends of a piston block 1.1 in a coaxial mode, the piston block 1.1 is installed in the cylinder 12, a gap is used for dynamic sealing between the piston 1.1 and the cylinder 12, and pressure equalizing grooves are formed in the piston 1.1. The piston rod 1.2 is arranged in the end cover 10, the piston block 1.1 and the piston rod 1.2 form a piston body which axially moves in an inner cavity formed between the cylinder 12 and the end cover 10, and the inner cavity of the cylinder 12 is filled with oil.

As shown in fig. 5, a bearing sleeve 8 is sleeved between the piston rod 1.2 and the end cover 10, the end cover 10 and the bearing sleeve 8 are in interference fit through a straight hole, and an outer ring of the linear bearing 9 and an inner hole of the bearing sleeve 8 are in interference fit. Bearing sleeve 8 is through first bolt 4, first packing ring 5 fixed mounting is to end cover 10, there is second sealing washer 14 and sealed through second sealing washer 14 between bearing sleeve 8 and the end cover 10, dust ring 2 is installed from outer end to inner in proper order to the inner peripheral surface of bearing sleeve 8, ste seals 3 and linear bearing 9, ste seals 3 and is in between dust ring 2 and linear bearing 9, dust ring 2, ste seals 3 and linear bearing 9 all install through the annular that bearing sleeve 8 inner peripheral surface was seted up separately, connect through dust ring 2 and ste seals 3 sealed dustproof between bearing sleeve 8 and the piston rod 1.2, it seals 3 to adopt ste between dynamic seal between piston rod 1.2 and bearing sleeve 8. A linear rolling connection guide is formed between the bearing sleeve 8 and the piston rod 1.2 through a linear bearing 9; the linear bearing 9 is a linear bearing with balls mounted in a circulating closed loop raceway, and one end close to the inner cavity is communicated with the inner cavity.

The bearing sleeve 8 is provided with an outer flange which is fixedly mounted on the outer end face of the end cover 10 through the first bolt 4 and the first gasket 5, so that the bearing sleeve 8 is fixedly connected with the end cover 10, and the linear bearing 9 is matched with the outer side hole shoulder of the end cover 10.

The linear bearing 9 is used as a bearing element of the piston rod 1.2 of the hydraulic cylinder, and is in contact transmission with the piston rod 1.2 in a rolling pair mode, but not in contact transmission in a sliding pair mode although a ball is adopted in the prior art. Fig. 6 is a schematic three-dimensional structure of a linear bearing, wherein a row of balls are arranged in the linear bearing, a certain distance is kept between the balls through a flexible retainer (not shown), the single row of balls can continuously and periodically move in a track, each row of balls is in contact with a shaft in a rolling friction mode when in a position and can bear radial force in one direction, the balls in the position 2 are not stressed, the movement mode of the balls is similar to that of a rolling bearing, and the balls can be ensured to be in contact transmission in a rolling pair mode all the time. Meanwhile, the linear bearing 9 is communicated with the hydraulic cylinder accommodating cavity, so that lubrication can be realized directly through hydraulic oil in work without an additional lubricating device.