阅读说明：本技术 蓄能器充液阀及液压制动系统 (Accumulator charging valve and hydraulic braking system ) 是由 张攸长 张铁匠 杨朋 于 2021-09-10 设计创作，主要内容包括：本发明涉及液压阀,公开了一种蓄能器充液阀,包括壳体和设置在壳体内的阀结构,壳体上包括压力油口、负载油口、回油口、蓄能器连接口和制动油口,阀结构包括压力补偿器、切断阀、单向阀、溢流阀、先导控制组件和制动阀,压力补偿器连接在压力油口和负载油口与切断阀之间,单向阀连接在切断阀与蓄能器连接口之间,先导控制组件连接在蓄能器连接口、回油口、压力补偿器和切断阀之间,以能够控制供应到压力补偿器控制油口和切断阀控制油口的压力,溢流阀连接在蓄能器连接口与回油口之间,制动阀连接在蓄能器连接口和回油口与制动油口之间。能够将蓄能器连接口的压力控制在设定范围,保证液压制动器的使用安全。本发明还提供了一种液压制动系统。(The invention relates to a hydraulic valve, and discloses an energy accumulator charging valve, which comprises a shell and a valve structure arranged in the shell, wherein the shell comprises a pressure oil port, a load oil port, an oil return port, an energy accumulator connecting port and a brake oil port, the valve structure comprises a pressure compensator, a stop valve, a check valve, an overflow valve, a pilot control assembly and a brake valve, the pressure compensator is connected between the pressure oil port, the load oil port and the stop valve, the check valve is connected between the stop valve and the energy accumulator connecting port, the pilot control assembly is connected between the energy accumulator connecting port, the oil return port, the pressure compensator and the stop valve so as to control the pressure supplied to the pressure compensator control oil port and the pressure of the cut-off valve control oil port, the overflow valve is connected between the energy accumulator connecting port and the oil return port, and the brake valve is connected between the energy accumulator connecting port and the oil return port and the brake oil port. The pressure of the accumulator connecting port can be controlled within a set range, and the use safety of the hydraulic brake is ensured. The invention also provides a hydraulic brake system.)

1. The utility model provides an energy storage ware prefill valve, is in including casing and setting valve structure in the casing, including pressure hydraulic fluid port (P), load hydraulic fluid port (B), oil return port (T), energy storage ware connector (AC) and braking hydraulic fluid port (Pi) of external connection on the casing, a serial communication port, valve structure includes pressure compensator (1), trip valve (2), check valve (3), overflow valve (4), guide control subassembly (5) and brake valve (6), pressure compensator (1) is connected pressure hydraulic fluid port (P) and load hydraulic fluid port (B) with between the oil inlet of trip valve (2), the oil-out of trip valve (2) with the oil inlet of check valve (3) is connected, the oil-out of check valve (3) with energy storage ware connector (AC) is connected, guide control subassembly (5) are connected energy storage ware connector (AC), Between oil return opening (T), pressure compensator (1) and trip valve (2), in order to can control the supply to pressure compensator (1) control hydraulic fluid port with the pressure of the pressure fluid of trip valve (2) control hydraulic fluid port, overflow valve (4) are connected energy storage connector (AC) with between oil return opening (T), brake valve (6) are connected energy storage connector (AC) and oil return opening (T) with between braking hydraulic fluid port (Pi).

2. Accumulator charging valve according to claim 1, characterized in that the valve structure further comprises a main overflow valve (41), the main overflow valve (41) being connected between the pressure port (P) and the return port (T).

3. Accumulator charging valve according to claim 1, characterized in that the valve structure further comprises a damping orifice (7), the damping orifice (7) being connected between the pressure compensator (1) and the shut-off valve (2).

4. Accumulator charging valve according to claim 3, characterized in that the valve structure further comprises a sieve (8), said sieve (8) being connected between the pressure compensator (1) and the orifice (7).

5. The accumulator charging valve according to claim 1, further comprising a pressure measuring oil port (M) and a pressure relay oil port (J) on the housing, wherein the pressure measuring oil port (M) and the pressure relay oil port (J) are both communicated with the accumulator connection port (AC) so as to be connected with an oil pressure sensor through the pressure measuring oil port (M) and connected with a pressure relay through the pressure relay oil port (J).

6. The accumulator charging valve according to any one of claims 1 to 5, characterized in that the pressure compensator (1) comprises a pressure compensation valve spool (11), a pressure compensation spring (12), a first pressure plug (13), a second pressure plug (14) and a pressure compensation valve cavity (15), the pressure compensation valve cavity (15) is arranged in the housing, the pressure compensation valve cavity (15) comprises an end surface cavity (151), a load cavity (152), a pressure cavity (153) and a pressure compensation spring cavity (154), the end surface cavity (151) and the pressure compensation spring cavity (154) are respectively arranged at two sides of the pressure compensation valve cavity (15), the load cavity (152) is connected with the load oil port (B), and the pressure cavity (153) is respectively connected with the pressure port (P) and a pressure transmission oil passage (S) arranged in the housing, the pressure compensation spring cavity (154) is connected with the pilot control assembly (5) through a control oil duct (X) arranged in the shell, the pressure compensation valve core (11) is arranged in the pressure compensation valve cavity (15) and can slide in the pressure compensation valve cavity (15), the first pressure plug (13) is arranged at the end part of the end face cavity (151), the second pressure plug (14) is arranged at the end part of the pressure compensation spring cavity (154), the pressure compensation spring (12) is arranged in the pressure compensation spring cavity (154) and is positioned between the second pressure plug (14) and the pressure compensation valve core (11) so as to form thrust pointing to the direction of the end face cavity (151) on the pressure compensation valve core (11), and a through flow pipeline (111) for communicating the end face cavity (151) with the pressure cavity (153) is arranged in the pressure compensation valve core (11), and a throttling groove (112) is formed in the outer side of the pressure compensation valve core (11), so that when the pressure compensation valve core (11) is positioned in the pressure compensation valve cavity (15) at a position adjacent to the first pressure plug (13), the pressure cavity (153) is communicated with the load cavity (152) through the throttling groove (112), and when the pressure compensation valve core (11) is positioned in the pressure compensation valve cavity (15) at a position adjacent to the second pressure plug (14), the pressure cavity (153) is directly communicated with the load cavity (152).

7. The accumulator charging valve according to any one of claims 1 to 5, characterized in that the pilot control assembly (5) comprises a lower limit pressure detection valve (51), a ram (52) and an upper limit pressure detection valve (53), the lower limit pressure detection valve (51) and the upper limit pressure detection valve (53) being provided on both sides of the ram (52) and being interlocked by the ram (52) such that one of the lower limit pressure detection valve (51) and the upper limit pressure detection valve (53) is in an open state and the other is in a closed state; a control oil duct (X), an energy storage oil duct (E) and an oil return duct (Ti) are arranged in the shell, the control oil duct (X) is respectively connected with control oil ports of the pressure compensator (1) and the stop valve (2), the energy storage oil duct (E) is connected with an energy storage connector (AC), the oil return duct (Ti) is connected with the oil return port (T), an oil inlet of the lower limit pressure detection valve (51) is connected with the energy storage oil duct (E), an oil inlet of the upper limit pressure detection valve (53) is connected with the oil return duct (Ti), oil outlets of the lower limit pressure detection valve (51) and the upper limit pressure detection valve (53) are connected with each other to form a pilot signal cavity (54), the ejector rod (52) is arranged in the pilot signal cavity (54), and the pilot signal cavity (54) is connected with the control oil duct (X), when the oil inlet pressure of the lower limit pressure detection valve (51) is lower than a set lower limit pressure, the lower limit pressure detection valve (51) is opened and the upper limit pressure detection valve (53) is closed, when the oil inlet pressure of the lower limit pressure detection valve (51) is higher than the set upper limit pressure, the upper limit pressure detection valve (53) is opened and the lower limit pressure detection valve (51) is closed, and when the oil inlet of the lower limit pressure detection valve (51) is positioned between the set lower limit pressure and the set upper limit pressure, the lower limit pressure detection valve (51) and the upper limit pressure detection valve (53) keep the original state.

8. The accumulator charging valve according to claim 7, characterized in that a pilot control valve cavity is arranged in the housing, the pilot control assembly (5) comprises a pilot end cover (514), a pilot return spring (513), a pilot return spring seat (512), a lower limit pressure detection valve core (511), a pilot valve sleeve (55), an upper limit pressure detection valve core (531), a pilot pressure regulation spring seat (532), a pilot pressure regulation spring (533), a pressure regulation screw (534), a pilot plug (535) and the ejector rod (52), the pilot valve sleeve (55) is installed in the middle of the pilot control valve cavity, the ejector rod (52) is installed in the pilot valve sleeve (55) and can slide in the pilot valve sleeve (55), and the pilot signal cavity (54) is formed between the ejector rod (52) and the pilot valve sleeve (55), the pilot valve sleeve (55) is provided with a small hole, so that the control oil passage (X) is communicated with the pilot signal cavity (54), the lower limit pressure detection valve core (511), the pilot reset spring seat (512), the pilot reset spring (513) and the pilot end cover (514) are sequentially arranged on one side of the pilot valve sleeve (55) in the pilot control valve cavity to form the lower limit pressure detection valve (51), the pilot end cover (514) is sealed at one end of the pilot control valve cavity, an end cover cavity (515) with one sealed end is arranged in the pilot end cover (514), the energy storage oil passage (E) is communicated with the end cover cavity (515), the pilot reset spring (513) is arranged in the end cover cavity (515) and between the sealed end of the end cover cavity (515) and the pilot reset spring seat (512) to push the pilot reset spring seat (512) to the lower limit pressure detection valve core (511), so that the lower limit pressure detection valve core (511) can be pressed on the end part of the pilot valve sleeve (55) to block the connecting passage between the end cover cavity (515) and the pilot signal cavity (54), the upper limit pressure detection valve core (531), the pilot pressure adjusting spring seat (532), the pilot pressure adjusting spring (533), the pressure adjusting screw (534) and the pilot choke plug (535) are sequentially installed on the other side of the pilot valve sleeve (55) in the pilot control valve cavity to form the upper limit pressure detection valve (53), the pilot choke plug (535) is sealed at the other end of the pilot control valve cavity, the pressure adjusting screw (534) is adjustably installed in the pilot control valve cavity, and the pilot control valve cavity between the pressure adjusting screw (534) and the pilot pressure adjusting spring seat (532) is formed into a pressure adjusting spring cavity (536), the pressure adjusting spring cavity (536) is communicated with the oil return channel (Ti), the pilot pressure adjusting spring (533) is arranged in the pressure adjusting spring cavity (536) and between the pressure adjusting screw (534) and the pilot pressure adjusting spring seat (532) to push the pilot pressure adjusting spring seat (532) to the upper limit pressure detection valve core (531), so that the upper limit pressure detection valve core (531) can be pressed at the end part of the pilot valve sleeve (55) to block a connecting passage between the pressure adjusting spring cavity (536) and the pilot signal cavity (54).

9. The accumulator charging valve according to any one of claims 1 to 5, characterized in that the shut-off valve (2) comprises a reversing valve stem (21), a reversing spring seat (22), a reversing spring (23), a reversing plug (24) and a shut-off valve cavity (25), the shut-off valve cavity (25) is arranged in the housing, the shut-off valve cavity (25) comprises a reversing spring cavity (251), a shut-off valve front cavity (252), a shut-off valve rear cavity (253) and a reversing control cavity (254) which are arranged in sequence, the reversing spring cavity (251) is connected with the pilot control assembly (5) through a control oil passage (X) arranged in the housing, the shut-off valve front cavity (252) is connected with the pressure compensator (1) through a front pressure oil passage (F) arranged in the housing, the shut-off valve rear cavity (253) is connected with an oil inlet of the check valve (3) through a rear pressure oil passage (G) arranged in the housing, the reversing control cavity (254) is connected with the energy accumulator connecting port (AC) through an energy accumulation pressure oil passage (K) arranged in the shell, the reversing valve rod (21) is arranged in the cut-off valve cavity (25), and two ends of the reversing valve rod (21) are respectively positioned in the reversing spring cavity (251) and the reversing control cavity (254), the reversing plug (24) is sealed at one end of the reversing spring cavity (251), the reversing spring (23) is arranged between the reversing plug (24) and the reversing spring seat (22), so as to be able to rest on the reversing valve rod (21) via the reversing spring seat (22), the reversing valve rod (21) can slide in the cut-off valve cavity (25), so as to be able to switch the communication state between the pre-shutoff valve chamber (252) and the post-shutoff valve chamber (253).

10. A hydraulic brake system, characterized by comprising a system power pump source, an accumulator (9), a hydraulic parking brake and an accumulator charging valve according to any one of claims 1-9, wherein the system power pump source is connected with the pressure oil port (P), the accumulator (9) is connected with the accumulator connection port (AC), and a hydraulic driving oil port of the hydraulic parking brake is connected with the brake oil port (Pi).

Technical Field

The invention relates to a hydraulic valve, in particular to an accumulator charging valve. The invention also relates to a hydraulic brake system.

Background

The brake system is provided in the traveling machine, forcibly reduces the traveling speed of the traveling machine or keeps the traveling machine in a stopped state, and plays an extremely important role in the traveling machine. The full hydraulic brake system fills liquid into the energy accumulator through the liquid filling valve of the energy accumulator, maintains the pressure of the energy accumulator in a stable range, and provides power for the brake loop during braking, so that the braking efficiency is improved. The accumulator prefill valve arranges in a flexible way, can arrange in the position far away from the braking, also can arrange in nearer position, can effectively reduce the work number of times of hydraulic pump, can guarantee brake pressure's stability, when the power supply broke down, can also carry out a plurality of times braking as emergent power supply to the parking is overhauld, guarantees driving safety.

The working principle of the most widely applied accumulator charging valve is shown in fig. 1, pressure oil enters a pressure compensator 1 through a pressure oil port P and charges an accumulator 9 through a check valve 3, and the pressure oil in the accumulator 9 is delivered to a parking brake under the control of a brake valve 6 to brake a walking machine. However, in the hydraulic brake system using the accumulator charging valve in this form, when the pressure of the load port B is significantly higher than the maximum bearing pressure of the brake cylinder of the parking brake, the brake cylinder is damaged by the high-pressure hydraulic oil because the pressure port P is always communicated with the accumulator 9. This form of accumulator charging valve can only be used where the pressure at the load port B is lower than the maximum withstanding pressure of the brake cylinder. However, the lower maximum brake cylinder pressure and the higher load port B pressure typically greatly limit the range of use of this type of accumulator charging valve.

In order to reduce the charging pressure of the accumulator during charging at higher load port B pressures, a pressure reducing/relieving valve 31 may be provided between the non-return valve 3 and the accumulator 9, forming an accumulator charging valve as shown in fig. 2. The pressure of the hydraulic oil passing through the pressure reducing relief valve 31 is reduced by a set value, so that the pressure of the hydraulic oil in the oil path at the accumulator 9, the brake valve 6 and the like after the pressure reducing relief valve 31 can be reduced, and the pressure of the hydraulic oil supplied to the parking brake does not exceed the maximum bearing pressure of the brake cylinder. However, the pressure reducing and overflowing valve is usually in a sliding valve structure, and continuous leakage exists, so that the pressure maintaining effect of the accumulator 9 is poor, and the accumulator 9 is frequently filled with liquid. Furthermore, when the power source is stopped, the pressure in the accumulator 9 is quickly removed, so that the parking brake cannot be braked or released.

The accumulator charging valve also has a relief valve overflow 31 arranged before the check valve 3, and the check valve 3 prevents the hydraulic oil in the accumulator 9 from leaking through the relief valve overflow 31, thus forming the accumulator charging valve shown in fig. 3. However, the back-set check valve 3 may prevent the relief valve 31 from performing the relief protection function for the accumulator 9, and when the relief valve 31 is damaged, the load pressure may be transmitted to the accumulator 9 and the parking brake, and the brake cylinder may be damaged.

Disclosure of Invention

The invention aims to solve the technical problem of providing an accumulator charging valve which can avoid the influence of the pressure of a load port on the charging pressure of an accumulator and ensure that the accumulator is charged with liquid preferentially and safely

The invention further aims to provide a hydraulic brake system which can ensure that an energy accumulator can keep effective brake pressure for a long time and ensure brake safety.

In order to solve the technical problems, the invention provides an accumulator charging valve on one hand, which comprises a shell and a valve structure arranged in the shell, wherein the shell comprises a pressure oil port, a load oil port, an oil return port, an accumulator connecting port and a brake oil port which are externally connected, the valve structure comprises a pressure compensator, a cut-off valve, a one-way valve, an overflow valve, a pilot control assembly and a brake valve, the pressure compensator is connected between the pressure oil port and the load oil port and the oil inlet of the cut-off valve, the oil outlet of the cut-off valve is connected with the oil inlet of the one-way valve, the oil outlet of the one-way valve is connected with the accumulator connecting port, the pilot control assembly is connected between the accumulator connecting port, the oil return port, the pressure compensator and the cut-off valve so as to control the pressure of pressure liquid supplied to the pressure compensator control oil port and the cut-off valve control oil port, the overflow valve is connected between the energy accumulator connector and the oil return port, and the brake valve is connected between the energy accumulator connector and the oil return port and the brake oil port.

Preferably, the valve structure further comprises a main overflow valve, and the main overflow valve is connected between the pressure oil port and the oil return port. In this preferred technical scheme, main overflow valve can be when the pressure of pressure hydraulic fluid port exceedes the setting value, with the pressure fluid overflow of pressure hydraulic fluid port department to oil return opening department to reduce the pressure of pressure hydraulic fluid port department, prevent that pressure is too high in the pressure hydraulic fluid port.

Preferably, the valve structure further comprises a damping orifice connected between the pressure compensator and the shut-off valve. Through the preferable technical scheme, the change speed of the pressure liquid pressure in the stop valve can be slowed down, frequent switching of the stop valve caused by short pressure change pulses is prevented, the liquid filling speed of the accumulator liquid filling valve can be set through the damping holes, and the damping holes with different specifications and sizes can be selected according to different liquid filling speeds.

Further preferably, the valve structure further comprises a strainer connected between the pressure compensator and the orifice. In this preferred technical scheme, the setting of filter screen can filter the impurity in the pressure fluid, guarantees the clean of pressure fluid and the normal work of hydraulic braking system.

Preferably, the shell further comprises a pressure measuring oil port and a pressure relay oil port, wherein the pressure measuring oil port and the pressure relay oil port are communicated with the energy accumulator connecting port so as to be connected with the oil pressure sensor through the pressure measuring oil port, and the pressure relay oil port is connected with the pressure relay. Through this preferred technical scheme, can detect the pressure fluid pressure of energy storage ware connection mouth department to can be when the hydraulic pressure of energy storage ware connection mouth department is less than the setting value, trigger alarm device sends alarm information.

As a preferred scheme, the pressure compensator includes a pressure compensation valve core, a pressure compensation spring, a first pressure plug, a second pressure plug and a pressure compensation valve cavity, the pressure compensation valve cavity is disposed in the housing, the pressure compensation valve cavity includes an end surface cavity, a load cavity, a pressure cavity and a pressure compensation spring cavity, the end surface cavity and the pressure compensation spring cavity are respectively disposed at two sides of the pressure compensation valve cavity, the load cavity is connected with the load oil port, the pressure cavity is respectively connected with the pressure oil port and a pressure transmission oil passage disposed in the housing, the pressure compensation spring cavity is connected with the pilot control assembly through a control oil passage disposed in the housing, the pressure compensation valve core is disposed in the pressure compensation valve cavity and can slide in the pressure compensation valve cavity, the first pressure plug is mounted at an end of the end surface cavity, the second pressure plug is arranged at the end part of the pressure compensation spring cavity, the pressure compensation spring is arranged in the pressure compensation spring cavity and is positioned between the second pressure plug and the pressure compensation valve core so as to form thrust pointing to the direction of the end surface cavity on the pressure compensation valve core, a channel for communicating the end surface cavity with the pressure cavity is arranged in the pressure compensation valve core, a throttling groove is arranged on the outer side of the pressure compensation valve core, so that when the pressure compensation valve core is positioned in the position, adjacent to the first pressure plug, of the pressure compensation valve cavity, the pressure cavity is communicated with the load cavity through the throttling groove, and when the pressure compensation valve core is positioned in the position, adjacent to the second pressure plug, of the pressure compensation valve cavity, the pressure cavity is directly communicated with the load cavity. Through this preferred technical scheme, can guarantee that the pressure of pressure hydraulic fluid port is greater than the pressure of pressure compensation spring and the pressure sum of control oil duct all the time when the pressure of load hydraulic fluid port is lower to guarantee the required pressure fluid pressure of hydraulic braking system normal work.

Preferably, the pilot control assembly comprises a lower limit pressure detection valve, a mandril and an upper limit pressure detection valve, wherein the lower limit pressure detection valve and the upper limit pressure detection valve are arranged on two sides of the mandril and can be linked under the action of the mandril, so that one of the lower limit pressure detection valve and the upper limit pressure detection valve is in an open state, and the other one of the lower limit pressure detection valve and the upper limit pressure detection valve is in a closed state; the shell is internally provided with a control oil duct, an energy storage oil duct and an oil return duct, the control oil duct is respectively connected with a control oil port of the pressure compensator and a control oil port of the cut-off valve, the energy storage oil duct is connected with the energy storage connector, the oil return duct is connected with the oil return port, an oil inlet of the lower limit pressure detection valve is connected with the energy storage oil duct, an oil inlet of the upper limit pressure detection valve is connected with the oil return duct, oil outlets of the lower limit pressure detection valve and the upper limit pressure detection valve are mutually connected to form a pilot signal cavity, the ejector rod is arranged in the pilot signal cavity, the pilot signal cavity is connected with the control oil duct, when the oil inlet pressure of the lower limit pressure detection valve is lower than the set lower limit pressure, the lower limit pressure detection valve is opened, the upper limit pressure detection valve is closed, and when the oil inlet pressure of the lower limit pressure detection valve is higher than the set upper limit pressure, and when the upper limit pressure detection valve is opened and the lower limit pressure detection valve is closed, and the oil inlet of the lower limit pressure detection valve is positioned between the lower limit pressure and the upper limit pressure, the lower limit pressure detection valve and the upper limit pressure detection valve keep the original states. Through the preferred technical scheme, when the pressure of the energy accumulator connecting port is lower than the set lower limit pressure, the pilot control assembly can be communicated with the control oil duct and the energy storage oil duct, the pressure of the energy accumulator connecting port is transmitted to the control port of the cut-off valve, the cut-off valve is controlled to be opened, and the pressure liquid of the pressure oil port is transmitted to the energy accumulator connecting port to fill the energy accumulator. When the pressure of the accumulator connector is higher than the set upper limit pressure, the pilot control assembly can be communicated with the control oil duct and the oil return channel, so that the pressure of the control port of the stop valve is unloaded, the stop valve is controlled to be closed, the pressure of the accumulator connector is not higher than the set upper limit pressure, and the charging pressure of the accumulator is not higher than the highest bearing pressure of a brake cylinder of the parking brake.

Further preferably, a pilot control valve cavity is arranged in the housing, the pilot control assembly comprises a pilot end cover, a pilot return spring seat, a lower limit pressure detection valve core, a pilot valve housing, an upper limit pressure detection valve core, a pilot pressure adjustment spring seat, a pilot pressure adjustment spring, a pressure adjustment screw, a pilot plug and the ejector rod, the pilot valve housing is arranged in the middle of the pilot control valve cavity, the ejector rod is arranged in the pilot valve housing and can slide in the pilot valve housing, the pilot signal cavity is formed between the ejector rod and the pilot valve housing, a small hole is formed in the pilot valve housing to enable the control oil passage to be communicated with the pilot signal cavity, and the lower limit pressure detection valve core, the pilot return spring seat, the pilot return spring and the pilot end cover are sequentially arranged on one side of the pilot valve housing in the pilot control valve cavity, the lower limit pressure detection valve is formed, the pilot end cover is sealed at one end of the pilot control valve cavity, an end cover cavity with one sealed end is arranged in the pilot end cover, the energy storage oil duct is communicated with the end cover cavity, the pilot return spring is arranged in the end cover cavity and between the sealed end of the end cover cavity and the pilot return spring seat so as to push the pilot return spring seat to the lower limit pressure detection valve core, the lower limit pressure detection valve core is a cone valve core and can be pressed at the end part of the pilot valve cavity under the action of the return spring so as to cut off a connecting passage between the end cover cavity and the pilot signal cavity, and the upper limit pressure detection valve core, the pilot pressure adjustment spring seat, the pilot pressure adjustment spring, the pressure adjustment screw and the pilot plug are sequentially arranged at the other side of the pilot valve cavity in the pilot control valve cavity, forming the upper limit pressure detection valve, sealing the pilot plug at the other end of the pilot control valve cavity, the pressure adjusting screw is adjustably installed in the pilot control valve cavity, the pilot control valve cavity between the pressure adjusting screw and the pilot pressure adjusting spring seat is formed into a pressure adjusting spring cavity, the pressure adjusting spring cavity is communicated with the oil return channel, the pilot pressure adjusting spring is arranged in the pressure adjusting spring cavity and between the pressure adjusting screw and the pilot pressure adjusting spring seat, the pressure regulating spring seat is pushed to the upper limit pressure detection valve core, the upper limit pressure detection valve core is a cone valve core and can be pressed on the end part of the pilot valve sleeve under the action of the pressure regulating spring so as to cut off a connecting passage between the pressure regulating spring cavity and the pilot signal cavity. In this preferred technical scheme, lower limit pressure detects the case and upper limit pressure detects the case and is the cone valve core, and sealing performance is better, can improve the pressurize function of the energy storage ware of connecting on the energy storage ware connector. The arrangement of the pressure adjusting screw can adjust the elastic force of the pilot pressure adjusting spring, so that the set upper limit pressure, namely the maximum charging pressure of the energy accumulator, is adjusted, and the pressure of the energy accumulator is not greater than the maximum bearing pressure of the brake cylinder of the parking brake.

Preferably, the trip valve includes switching-over valve rod, switching-over spring holder, switching-over spring, switching-over end cap and cuts off the valve pocket, it sets up in the casing to cut off the valve pocket, cut off the valve pocket including the switching-over spring chamber, trip valve antetheca, trip valve back chamber and the switching-over control chamber of arranging in proper order, the switching-over spring chamber through set up in the casing control oil duct with being connected of pilot control subassembly, the trip valve antetheca through set up in the casing preceding pressure oil duct with pressure compensator is connected, the trip valve back chamber through set up in the casing back pressure oil duct with the oil inlet of check valve is connected, the switching-over control chamber through set up in the casing energy storage pressure oil duct with the energy storage connector is connected, the switching-over valve rod is installed in the trip valve pocket, just the both ends of switching-over valve rod are located respectively switching-over spring chamber and switching-over control chamber, the switching-over end cap is sealed the one end in switching-over spring chamber, the switching-over spring sets up the switching-over end cap with between the switching-over spring holder, in order to pass through the switching-over spring holder supports and leans on the switching-over valve rod, the switching-over valve rod can slide in the shutoff valve chamber, in order to switch before the trip valve chamber with communicating state behind the trip valve between the chamber. Through this preferred technical scheme, the switching-over valve rod can reach the upper limit pressure of setting for at the pressure of energy storage ware connector, switches the valve position when control oil duct pressure release, closes the liquid way between trip valve front chamber and the trip valve rear chamber, prevents that the pressure of energy storage ware connector from continuing to rise.

The invention provides a hydraulic brake system in a second aspect, which comprises a system power pump source, an energy accumulator, a hydraulic parking brake and the energy accumulator charging valve provided by the first aspect of the invention, wherein the system power pump source is connected with the pressure oil port, the energy accumulator is connected with the energy accumulator connecting port, and a hydraulic driving oil port of the hydraulic parking brake is connected with the brake oil port.

Through the technical scheme, the pilot control assembly can output the pilot control signal when the pressure at the accumulator connecting port reaches the set value, and the cut-off valve is controlled to cut off the hydraulic passage between the pressure oil port and the accumulator connecting port, so that the charging pressure of the accumulator connected to the accumulator connecting port is not more than the set value, the pressure in the brake cylinder of the hydraulic parking brake connected with the brake oil port is not more than the highest bearing pressure of the brake cylinder, and the brake cylinder is prevented from being damaged. The overflow valve connected between the energy accumulator connecting port and the oil return port is arranged, so that the pressure at the energy accumulator connecting port can be guaranteed not to exceed the overflow pressure of the overflow valve, a guarantee is provided for a brake cylinder of the hydraulic parking brake, and the brake cylinder is prevented from being damaged due to high pressure when the switching valve is damaged. The accumulator charging valve can ensure the pressure of the accumulator connecting port under the condition that the pressures of the load oil ports are different, and can control the pressure of the accumulator connecting port below a set value so as to ensure the normal work of the hydraulic parking brake. The hydraulic braking system can provide lower energy accumulator charging pressure under the condition that the pressure of the load oil port is higher, and the normal work of the hydraulic parking brake is ensured.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

FIG. 1 is a hydraulic schematic of a prior art accumulator charge valve;

FIG. 2 is a hydraulic schematic of another prior art accumulator charge valve;

FIG. 3 is a hydraulic schematic of yet another prior art accumulator charge valve;

FIG. 4 is a hydraulic schematic of one embodiment of an accumulator charge valve of the present invention;

FIG. 5 is a schematic diagram of the internal structure of one embodiment of an accumulator charge valve of the present invention;

FIG. 6 is a block diagram of a pressure compensator in one embodiment of an accumulator charge valve of the present invention;

FIG. 7 is a block diagram of a pilot control assembly in one embodiment of an accumulator charge valve of the present invention;

FIG. 8 is a block diagram of a shut-off valve in one embodiment of the accumulator charge valve of the present invention.

Description of the reference numerals

1 pressure compensator 11 pressure compensating valve core

111 throughflow conduit 112 throttling groove

12 pressure compensation spring 13 first pressure plug

14 second pressure plug 15 pressure compensation valve cavity

151 end face cavity 152 load cavity

153 pressure chamber 154 pressure compensating spring chamber

2-cut-off valve 21 reversing valve rod

22 reversing spring seat 23 reversing spring

24 reversing plug 25 cut-off valve cavity

251 reversing spring cavity 252 cut-off valve front cavity

Back cavity 254 reversing control cavity of 253 cut-off valve

3 one-way valve 31 pressure reducing overflow valve

4 relief valve 41 main relief valve

5 pilot control assembly 51 lower limit pressure detection valve

511 lower limit pressure detection valve core 512 pilot return spring seat

513 Pilot return spring 514 pilot end cap

515 end cap cavity 52 ram

53 upper limit pressure detection valve 531 upper limit pressure detection valve core

532 pilot pressure regulating spring seat 533 pilot pressure regulating spring

534 pressure adjusting screw 535 leading plug

536 pressure regulating spring cavity 54 pilot signal cavity

6 brake valve of 55 pilot valve sleeve

7 damping hole 8 filter screen

9 energy accumulator 10 pressure relay

AC energy accumulator connector B load oil port

E energy storage oil duct F front pressure oil duct

Oil port of J pressure relay of G rear pressure oil duct

K energy storage pressure oil duct M pressure measuring oil port

P pressure port Pi brake port

T oil return port of S pressure transmission oil duct

Ti oil return passage X control oil passage

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, and therefore the features defined "first", "second" may explicitly or implicitly include one or more of said features.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; either directly or indirectly through intervening media, either internally or in any combination thereof. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

As shown in fig. 4-8, one embodiment of the accumulator charge valve of the present invention includes a housing and a valve structure disposed within the housing. The shell is at least provided with a pressure oil port P used for being connected with a power source, a load oil port B used for being connected with a hydraulic actuating mechanism, an oil return port T used for being connected with a hydraulic oil tank, an energy accumulator connecting port AC used for being connected with an energy accumulator and a braking oil port Pi used for being connected with a hydraulic brake. The valve structure is arranged between different oil ports or connecting ports so as to control connecting liquid paths between the different oil ports or the connecting ports. The valve structure comprises a pressure compensator 1, a cut-off valve 2, a one-way valve 3, an overflow valve 4, a pilot control assembly 5 and a brake valve 6. Pressure compensator 1 is connected between pressure hydraulic fluid port P and load hydraulic fluid port B and trip valve 2, on the one hand will export load hydraulic fluid port B and trip valve 2 through the leading-in pressure liquid of pressure hydraulic fluid port P, on the other hand can be lower at the required pressure liquid pressure of hydraulic actuator, also namely under the lower condition of pressure liquid pressure of load hydraulic fluid port B, form the choke between pressure hydraulic fluid port P and load hydraulic fluid port B, just so can guarantee no matter load B mouth pressure is how, pressure hydraulic fluid port P department can both have the pressure liquid input of a higher pressure, thereby guarantee that the pressure of the pressure liquid of pressure hydraulic fluid port P department can reach and guarantee that hydraulic brake normally works required pressure. The shut-off valve 2 and the check valve 3 are sequentially arranged on a liquid path between the pressure compensator 1 and the energy accumulator connecting port AC, and the shut-off valve 2 controls a channel of the liquid path between the pressure compensator 1 and an oil inlet of the check valve 3 so as to control whether pressure liquid introduced from the pressure oil port P can be supplied to the energy accumulator connecting port AC or not and fill the energy accumulator 9 with the liquid. The check valve 3 is connected between the cut-off valve 2 and the accumulator connecting port AC, and prevents the pressure fluid in the accumulator from leaking. The pilot control assembly 5 is connected between the accumulator connecting port AC, the oil return port T, the pressure compensator 1 and the trip valve 2, and can control the pressure of the pressure fluid output to the control oil port of the pressure compensator 1 and the control oil port of the trip valve 2 according to the pressure at the accumulator connecting port AC to control the working states of the pressure compensator 1 and the trip valve 2, so as to control the charging pressure of the accumulator 9 at a set pressure level, ensure that the pressure fluid pressure supplied to the hydraulic brake by the accumulator 9 does not exceed the maximum pressure which can be borne by the brake cylinder of the brake, and prevent the brake cylinder from being damaged. The overflow valve 4 is connected between the accumulator connection port AC and the oil return port T, and the appropriate overflow valve 4 is selected for use, so that the overflow valve 4 has an overflow pressure lower than the highest pressure that the brake cylinder of the brake can bear. In this way, when the pressure at the accumulator connecting port AC reaches the relief pressure, the relief valve 4 opens the relief, thereby ensuring that the pressure liquid pressure at the accumulator connecting port AC is always lower than the highest bearing pressure of the brake cylinder, forming double protection for the brake cylinder, and preventing the brake cylinder from being damaged due to overhigh pressure at the accumulator connecting port AC under the condition that the hydraulic element is damaged. The brake valve 6 is connected between the accumulator connection port AC and the oil return port T and the brake port Pi, and in general, the brake valve 6 may be a reversing valve, and preferably, an electromagnetic ball valve is used. When the brake valve 6 is in different reversing states, the brake oil port Pi can be switched to be communicated with the accumulator connecting port AC or communicated with the oil return port T, so that the brake cylinder of the hydraulic brake is controlled to brake or relieve, and the effect of braking or brake releasing is generated. The two brake oil ports Pi can be set to be communicated with each other to be respectively connected with a left parking brake and a right parking brake to brake and control left and right traveling wheels of the traveling machine.

In some embodiments of the accumulator charging valve of the present invention, as shown in fig. 4 and 5, the valve structure provided within the housing further includes a main relief valve 41. The main overflow valve 41 is disposed between the pressure port P and the oil return port T, and controls an upper limit of pressure of the pressure fluid introduced through the pressure port P, thereby ensuring safety of the hydraulic system.

In some embodiments of the accumulator charging valve of the present invention, as shown in fig. 4 and 5, the valve structure provided within the housing further comprises a damping orifice 7. The damping orifice 7 is arranged on the connection route between the pressure compensator 1 and the accumulator connection port AC, typically between the pressure compensator 1 and the shut-off valve 2. The damping holes 7 can play a throttling role, the damping holes 7 with different sizes are arranged, and the liquid filling speed of an energy accumulator 9 connected with the energy accumulator connecting port AC can be controlled.

As an embodiment of the accumulator charging valve of the present invention, as shown in fig. 4 and 5, the valve structure provided in the housing further includes a strainer 8. A filter screen 8 may be arranged between the pressure compensator 1 and the damping orifice 7, which filter the pressure fluid passing through the pressure compensator 1 and ensures a clean supply of pressure fluid to the accumulator 9.

In some embodiments of the accumulator charging valve of the present invention, as shown in fig. 4 and 5, a pressure measuring port M and a pressure relay port J are further provided on the housing. The pressure measuring oil port M and the pressure relay oil port J are both communicated with the energy accumulator connecting port AC, and can be connected with a liquid path of a pressure detection device through the pressure measuring oil port M, and a hydraulic sensor or a pressure gauge can be directly arranged on the pressure measuring oil port M to be used for detecting the pressure of the energy accumulator connecting port AC, namely the pressure in the energy accumulator 9. Pressure relay hydraulic fluid port J can be used for being connected with pressure relay, and pressure relay is equipped with lower limit alarm pressure, and when pressure fluid pressure when pressure relay hydraulic fluid port J department was less than this lower limit alarm pressure, pressure relay triggered alarm device sent alarm signal, reminds the pressure in the energy storage ware 9 to hang down excessively, and hydraulic brake is unreliable to be brakied, and the walking machinery has the safe risk.

In some embodiments of the accumulator charging valve of the present invention, as shown in fig. 6, a pressure compensation valve cavity 15 is disposed in the housing of the accumulator charging valve, and the pressure compensation valve core 11, the pressure compensation spring 12, the first pressure plug 13, the second pressure plug 14 and the pressure compensation valve cavity 15 are installed in the pressure compensation valve cavity 15, so as to form the pressure compensator 1. The pressure compensation valve cavity 15 is further provided with an end surface cavity 151, a load cavity 152, a pressure cavity 153 and a pressure compensation spring cavity 154, wherein the end surface cavity 151 and the pressure compensation spring cavity 154 are respectively arranged at two sides of the pressure compensation valve cavity 15, the pressure compensation valve core 11 is installed in the pressure compensation valve cavity 15, and two ends of the pressure compensation valve core 11 are respectively located in the end surface cavity 151 and the pressure compensation spring cavity 154. A first pressure plug 13 is mounted at the end of the end face cavity 151 forming a seal of the end face cavity 151 with the exterior of the housing. The second pressure plug 14 is mounted to the end of the pressure compensating spring cavity 154 to form a seal between the pressure compensating spring cavity 154 and the exterior of the housing. The load chamber 152 and the pressure chamber 153 are disposed in the middle of the pressure compensation valve chamber 15, wherein the load chamber 152 is connected to the load port B, and the pressure chamber 153 is connected to the pressure port P and the pressure transmission oil passage S disposed in the housing, respectively. The pressure compensation spool 11 is slidable in the pressure compensation valve chamber 15 to be able to switch the connection state between the load chamber 152 and the pressure chamber 153. The pressure compensation spring cavity 154 is connected to the pilot control assembly 5 through a control oil passage X provided in the housing, and transmits a pilot pressure Px output from the pilot control assembly 5 into the pressure compensation spring cavity 154, and forms a thrust directed toward the end surface cavity 151 to an end portion of the pressure compensation spool 11. A pressure compensation spring 12 is disposed in the pressure compensation spring cavity 154 and between the second pressure plug 14 and the pressure compensation valve core 11, and the pressure compensation spring 12 can also form a thrust force directed toward the end surface cavity 151 on the pressure compensation valve core 11. The interior of the pressure compensation valve element 11 is provided with a flow duct 111 which communicates the end chamber 151 with the pressure chamber 153, the flow duct 111 being able to transfer the pressure fluid pressure in the pressure chamber 153 into the end chamber 151 and to form a thrust force on the end of the pressure compensation valve element 11 in the direction of the pressure compensation spring chamber 154. The pressure compensation spool 11 can slide in the pressure compensation valve cavity 15 under the combined action of the pilot pressure Px, the thrust of the pressure compensation spring 12 and the pressure of the pressure port P. A throttling groove 112 is formed in the outer side of the pressure compensation valve core 11, and when the pressure compensation valve core 11 is located at a position close to the first pressure plug 13 through the shape arrangement of the pressure compensation valve core 11, the pressure cavity 153 is communicated with the load cavity 152 through the throttling groove 112; when the pressure compensating valve cartridge 11 is positioned adjacent to the second pressure plug 14, the pressure chamber 153 is in direct communication with the load chamber 152. In this way, in the liquid filling state, when the input pressure of the pressure port P is high and is higher than the sum of the pilot pressure Px and the thrust of the pressure compensation spring 12, the pressure port P is transmitted into the end surface cavity 151, and the pressure compensation valve core 11 is pushed to slide to a position close to the second pressure plug 14. At this time, the pressure chamber 153 is directly communicated with the load chamber 152, and the pressure fluid at the pressure port P can enter the load port B more, so as to meet the working requirement of the hydraulic actuator. In the liquid charging state, when the required pressure of the hydraulic actuator connected to the load port B is low, the input pressure of the pressure port P generally needs to be reduced, so that the pressure at the pressure port P is lower than the sum of the pilot pressure Px and the thrust of the pressure compensation spring 12, and the pressure compensation valve spool 11 slides to a position close to the first pressure plug 13 under the action of the sum of the pilot pressure Px and the thrust of the pressure compensation spring 12. At this time, the pressure chamber 153 communicates with the load chamber 152 through the throttling groove 112, and the throttling groove 112 has a throttling and pressure reducing effect, so that the pressure at the pressure port P is higher than the pressure at the load port B. By setting the size of the throttle groove 112, it can be ensured that the pressure at the pressure port P is always kept at a level above the sum of the pilot pressure Px and the thrust of the pressure compensation spring 12, so as to ensure the minimum charging pressure of the accumulator 9, and ensure the reliable braking of the hydraulic brake.

In some embodiments of the accumulator charging valve of the present invention, as shown in fig. 7, the pilot control assembly 5 includes a lower limit pressure detection valve 51, a stem 52, and an upper limit pressure detection valve 53. The lower limit pressure detection valve 51 and the upper limit pressure detection valve 53 both have an oil inlet and an oil outlet, and the lower limit pressure detection valve 51 and the upper limit pressure detection valve 53 may adopt an appropriate valve structure capable of switching the on-off state between the oil inlet and the oil outlet, that is, the on-off state of the lower limit pressure detection valve 51 and the upper limit pressure detection valve 53. The lower limit pressure detection valve 51 and the upper limit pressure detection valve 53 are provided on both sides of the jack 52, and the spool of the lower limit pressure detection valve 51 and the spool of the upper limit pressure detection valve 53 can be linked by the jack 52 so that the upper limit pressure detection valve 53 is in a closed state when the lower limit pressure detection valve 51 is in an open state, and the upper limit pressure detection valve 53 is in an open state when the lower limit pressure detection valve 51 is in a closed state. A control oil duct X, an energy storage oil duct E and an oil return duct Ti are arranged in the shell, the control oil duct X is connected with a control oil port of the pressure compensator 1 and a control oil port of the cut-off valve 2 respectively, the energy storage oil duct E is connected with an energy storage connector AC, and the oil return duct Ti is connected with an oil return port T. An oil inlet of the lower limit pressure detection valve 51 is connected with the energy storage oil passage E, and an oil inlet of the upper limit pressure detection valve 53 is connected with the oil return passage Ti. Oil outlets of the lower limit pressure detection valve 51 and the upper limit pressure detection valve 53 are connected to each other to form a pilot signal chamber 54, and the pilot signal chamber 54 is connected to the control oil passage X. The push rod 52 is arranged in the pilot signal cavity 54, a flat groove is formed on the push rod 52, and oil outlets of the lower limit pressure detection valve 51 and the upper limit pressure detection valve 53 are kept communicated with each other. Both ends of the stem 52 interact with the valve core of the lower limit pressure detection valve 51 and the valve core of the upper limit pressure detection valve 53, respectively, to form an interlocking structure. When the pressure of the energy storage oil passage E is lower than the set lower limit pressure, the pressure is transmitted to the oil inlet of the lower limit pressure detection valve 51, and the push rod 52, the valve core of the lower limit pressure detection valve 51 and the valve core of the upper limit pressure detection valve 53 are interlocked under the influence of the pressure, so that the lower limit pressure detection valve 51 is opened, and the upper limit pressure detection valve 53 is closed. At this time, the oil inlet and the oil outlet of the lower limit pressure detection valve 51 are communicated, the oil inlet and the oil outlet of the upper limit pressure detection valve 53 are disconnected, so that the energy storage oil passage E is communicated with the control oil passage X, the pressure liquid at the energy storage connector AC can enter the control oil passage X, the control cut-off valve 2 is opened, and the pressure liquid at the pressure oil port P flows to the energy storage connector AC to fill the energy storage 9. As the pressure in the accumulator 9 increases step by step, the pressure in the accumulation oil passage E also increases step by step. When the pressure in the reservoir oil passage E is higher than the set upper limit pressure, the pressure is transmitted to the oil inlet of the lower limit pressure detection valve 51, and the stem 52, the valve element of the lower limit pressure detection valve 51, and the valve element of the upper limit pressure detection valve 53 are interlocked under the influence of the pressure, so that the upper limit pressure detection valve 53 is opened while the lower limit pressure detection valve 51 is closed. At this time, the oil inlet and the oil outlet of the lower limit pressure detection valve 51 are disconnected, the oil inlet and the oil outlet of the upper limit pressure detection valve 53 are communicated, so that the control oil passage X is communicated with the oil return passage Ti, the pressure liquid in the control oil passage X is unloaded through the oil return passage Ti, at this time, the shut-off valve 2 is closed, the pressure liquid at the pressure oil port P is prevented from continuously filling the accumulator 9, the pressure in the energy accumulation oil passage E is prevented from further rising, and the brake cylinder of the hydraulic brake is damaged due to the pressure liquid. At this time, the pressure in the accumulator 9, that is, the pressure in the accumulation oil passage E slowly decreases with the use of the hydraulic brake and the small leakage of the pressure fluid. When the pressure in the energy-accumulating oil passage E is between the set lower limit pressure and the set upper limit pressure, the spool 52, the spool of the lower limit pressure detection valve 51, and the spool of the upper limit pressure detection valve 53 are held at the original positions, and the lower limit pressure detection valve 51 and the upper limit pressure detection valve 53 are held in the original states, so that the pressure in the control oil passage X is held to be equal to the pressure in the energy-accumulating oil passage E, or to be held in an unloading state close to zero.

As a specific embodiment of the accumulator charging valve of the present invention, as shown in fig. 7, a pilot control valve cavity is provided in a housing of the accumulator charging valve, and the pilot control assembly 5 includes a pilot end cover 514, a pilot return spring 513, a pilot return spring seat 512, a lower limit pressure detection valve core 511, a pilot valve sleeve 55, an upper limit pressure detection valve core 531, a pilot pressure adjustment spring seat 532, a pilot pressure adjustment spring 533, a pressure adjustment screw 534, a pilot plug 535, and a push rod 52. The pilot valve sleeve 55 is installed in the middle of the pilot control valve cavity, and O-ring seals may be further disposed between the pilot valve sleeve 55 and the wall of the pilot control valve cavity at both ends of the pilot valve sleeve 55. The jack 52 is installed in the pilot valve housing 55 and is slidable in the pilot valve housing 55. A pilot signal cavity 54 is formed between the ram 52 and the pilot valve sleeve 55, and a small through hole is formed in the wall of the pilot valve sleeve 55 to communicate the control oil passage X and the pilot signal cavity 54 with each other. The lower limit pressure detection valve body 511, the pilot return spring seat 512, the pilot return spring 513, and the pilot end cover 514 are sequentially mounted on one side of the pilot valve sleeve 55 in the pilot control valve chamber, and form a lower limit pressure detection valve 51. The pilot end cover 514 is sealed at one end of the pilot control valve cavity, and an end cover cavity 515 with one end sealed and the other end communicated with the pilot control valve cavity is arranged in the pilot end cover 514. The energy storage oil passage E is communicated with the end cover cavity 515 to form an oil inlet of the lower limit pressure detection valve 51. The pilot return spring 513 is a spring with a small elastic force, the pilot return spring 513 is sleeved at one end of the pilot return spring seat 512 and is located between the closed end of the end cover cavity 515 and the pilot return spring seat 512, and the lower limit pressure detection valve core 511 is sleeved at the other end of the pilot return spring seat 512. The pilot return spring 513 can form an elastic force that pushes the pilot return spring seat 512 and the lower limit pressure detection spool 511 to move toward the pilot valve sleeve 55, so that the lower limit pressure detection spool 511 can press the end of the pilot valve sleeve 55 to block the connection path between the end cap chamber 515 and the pilot signal chamber 54. The upper limit pressure detection valve core 531, the pilot pressure adjusting spring seat 532, the pilot pressure adjusting spring 533, the pressure adjusting screw 534 and the pilot plug 535 are sequentially installed on the other side of the pilot valve sleeve 55 in the pilot control valve cavity to form the upper limit pressure detection valve 53. The pilot plug 535 is sealed at the other end of the pilot control valve cavity, and the pressure adjusting screw 534 is installed in the pilot control valve cavity inside the pilot plug 535 and can adjust the installation position of the pressure adjusting screw in the pilot control valve cavity. The pilot control valve cavity between the pressure adjusting screw 534 and the pilot plug 535 is communicated with the oil return passage Ti to form an oil inlet of the upper limit pressure detection valve 53. The pilot control valve cavity between the pressure adjusting screw 534 and the pilot pressure adjusting spring seat 532 forms a pressure adjusting spring cavity 536, a through hole is formed in the middle of the pressure adjusting screw 534 so that the pressure adjusting spring cavity 536 is communicated with the oil return passage Ti, the pilot pressure adjusting spring 533 is arranged in the pressure adjusting spring cavity 536 and is located between the pressure adjusting screw 534 and the pilot pressure adjusting spring seat 532, the upper limit pressure detection spool 531 is arranged between the pilot pressure adjusting spring seat 532 and the pilot valve sleeve 55, the pilot pressure adjusting spring seat 532 is pushed to the upper limit pressure detection spool 531 under the elastic force of the pilot pressure adjusting spring 533, the upper limit pressure detection spool 531 can be pressed on the end of the other side of the pilot valve sleeve 55, and a connecting passage between the pressure adjusting spring cavity 536 and the pilot signal cavity 54 is blocked. Both ends of the jack 52 abut on the lower limit pressure detection spool 511 and the upper limit pressure detection spool 531, respectively, so that only one of the lower limit pressure detection spool 511 and the upper limit pressure detection spool 531 can be brought into contact with the end of the pilot valve sleeve 55, and when one of the lower limit pressure detection valve 51 and the upper limit pressure detection valve 53 is in a closed state, the other is inevitably in an open state. The lower limit pressure detection valve core 511 and the upper limit pressure detection valve core 531 are both provided as tapered valve cores, so that the sealing performance between the lower limit pressure detection valve core 511 and the upper limit pressure detection valve core 531 and the end of the pilot valve sleeve 55 is better.

When the lower pressure-limiting detection valve 51 is in a closed state and the upper limit pressure detection valve 53 is in an open state, the control oil duct X is communicated with the oil return duct Ti, the pressure in the control oil duct X and the oil return duct Ti is close to zero, the diameter of the contact part of the lower limit pressure detection valve core 511 and the end part of the pilot valve sleeve 55 is D1, the pressure Pe of the pressure liquid in the energy storage oil duct E acts on the lower pressure-limiting detection valve core 511 to form a thrust with the size of 1/4 pi D1D 1 Pe, which points to the direction of the upper limit pressure detection valve 53 and is transmitted to the ejector rod 52; the elastic force F of the pilot pressure adjusting spring 533 is transmitted to the plunger 52 through the pilot pressure adjusting spring seat 532 and the upper limit pressure detecting spool 531, and forms a thrust in the direction of the lower pressure limiting detection valve 51. At this time, the pressure Pe of the pressure fluid in the energy storage oil passage E is greater than the elastic force F of the pilot pressure adjusting spring 533, and the rod 52 is pushed to move toward the upper pressure limiting detection valve 53 until the lower limit pressure detection valve core 511 contacts with the end of the pilot valve sleeve 55, so that the lower limit pressure detection valve 51 is in a closed state, and the upper limit pressure detection valve 53 is in an open state. Since the elastic force F of the pilot pressure adjusting spring 533 is constant under the condition that the position of the pressure adjusting screw 534 is not changed, at this time, there is a set lower limit pressure P1 of the energy storage oil passage E, so that 1/4 pi D1D 1P 1F (ignoring the elastic force of the pilot return spring 513), when the pressure Pe of the pressure fluid in the energy storage oil passage E gradually drops to be lower than the set lower limit pressure P1, the thrust of the pressure fluid in the energy storage oil passage E to the push rod 52 is smaller than the thrust of the pilot pressure adjusting spring 533 to the push rod 52, and under the combined action of the two, the lower limit pressure detecting valve core 511, the push rod 52 and the upper limit pressure detecting valve core 531 move together in the direction of the lower limit pressure detecting valve 51 until the upper limit pressure detecting valve core 531 contacts with the end of the pilot valve sleeve 55, the lower limit pressure detecting valve 51 is opened, and the upper limit pressure detecting valve 53 is closed. At this time, the pilot signal chamber 54 is isolated from the oil return passage Ti and is communicated with the energy storage oil passage E, and the pressure Pe of the pressure fluid in the energy storage oil passage E acts on the plunger 52 and the upper limit pressure detection valve spool 531 to form a thrust having a magnitude of 1/4 × pi × D2 × D2 × Pe (D2 is a diameter of a contact portion between the upper limit pressure detection valve spool 531 and the end of the pilot valve sleeve 55) and directed toward the upper limit pressure detection valve 53. By arranging the structure of the inner hole of the pilot valve sleeve 55, D2 is smaller than D1, so that when the upper limit pressure detection valve 53 is closed under the condition of Pe being unchanged, the thrust in the direction of the upward pressure limiting detection valve 53 formed by the pressure liquid in the energy storage oil passage E is smaller and is far smaller than the elastic force F of the pilot pressure adjusting spring 533, and the upper limit pressure detection valve 53 keeps a closed state. At this time, the control oil duct X is communicated with the energy storage oil duct E, the cut-off valve 2 is opened, the pressure fluid of the pressure port P flows into the energy storage connector AC to charge the energy storage 9, and the pressure in the energy storage oil duct E gradually increases. Similarly, there is a set upper limit pressure P2 of the accumulator oil passage E, such that 1/4 × pi × D2 × D2 × P2 ═ F (ignoring the spring force of the pilot return spring 513), and when the pressure in the accumulator oil passage E is higher than the set upper limit pressure P2, the pressure of the pressure fluid in the accumulator oil passage E becomes higher than the urging force of the pilot pressure adjusting spring 533, and the lower limit pressure detection valve spool 511, the plunger 52, and the upper limit pressure detection valve spool 531 move together in the direction of the upper limit pressure detection valve 53 until the lower limit pressure detection valve spool 511 comes into contact with the end of the pilot valve sleeve 55, the lower limit pressure detection valve 51 closes, and the upper limit pressure detection valve 53 opens. At this time, the pilot signal cavity 54 is isolated from the energy storage oil passage E and communicated with the oil return passage Ti, the shut-off valve 2 is closed, and the charging of the energy accumulator 9 is stopped. The thrust of the pressure Pe of the pressure fluid in the energy storage oil passage E acting on the plunger 52 is restored to 1/4 pi D1D 1 Pe, which is much larger than the elastic force F of the pilot pressure adjusting spring 533, and the lower limit pressure detection valve 51 is kept closed. By adjusting the position of the pressure adjustment screw 534, the spring force F of the pilot pressure adjustment spring 533 can be adjusted, as well as the set lower limit pressure P1 and the set upper limit pressure P2.

In some embodiments of the accumulator charging valve of the present invention, as shown in fig. 8, the shut-off valve 2 comprises a reversing valve stem 21, a reversing spring seat 22, a reversing spring 23, a reversing plug 24, and a shut-off valve cavity 25. A shut-off valve cavity 25 is arranged in a shell of the accumulator charging valve, and a reversing spring cavity 251, a front shut-off valve cavity 252, a rear shut-off valve cavity 253 and a reversing control cavity 254 are further arranged in the shut-off valve cavity 25 in sequence. The reversing spring cavity 251 is connected with a pilot hydraulic oil output port of the pilot control assembly 5 through a control oil passage X arranged in the shell, and the front cavity 252 of the cut-off valve is connected with the pressure compensator 1 through a front pressure oil passage F arranged in the shell; specifically, it may be connected to a pressure transmission oil passage S provided in the housing through a front pressure oil passage F, and to a pressure chamber 153 in the pressure compensator 1 through the pressure transmission oil passage S. The rear cavity 253 of the cut-off valve is connected with an oil inlet of the one-way valve 3 through a rear pressure oil passage G arranged in the shell; the direction change control chamber 254 is connected to the accumulator connection port AC through an accumulator pressure oil passage K provided in the housing. The reversing valve rod 21 is installed in the cut-off valve chamber 25, and both ends of the reversing valve rod 21 are located in the reversing spring chamber 251 and the reversing control chamber 254, respectively. An O-shaped sealing ring can be arranged between the reversing valve rod 21 and the cut-off valve cavity 25, so that pressure liquid in the energy accumulator 9 is prevented from leaking through the cut-off valve 2, and the pressure maintaining effect on the energy accumulator 9 is achieved. The reversing spring cavity 251 is open to the surface of the housing, and the reversing plug 24 is sealed at the open end of the reversing spring cavity 251. The reversing spring 23 and the reversing spring seat 22 are both arranged in the reversing spring cavity 251, the reversing spring 23 is arranged between the reversing plug 24 and the reversing spring seat 22, and the reversing spring seat 22 is abutted against the reversing valve rod 21 under the elastic force action of the reversing spring 23 and can push the reversing valve rod 21 to slide towards the reversing control cavity 254 in the cut-off valve cavity 25. The pressure liquid in the energy storage pressure oil passage K can enter the reversing control cavity 254 and act on the end of the reversing valve rod 21 to form a thrust force for pushing the reversing valve rod 21 towards the reversing spring cavity 251. When the liquid pressure in the reversing control cavity 254 is low and the formed thrust on the reversing valve rod 21 is smaller than the elastic force of the reversing spring 23, the reversing valve rod 21 slides towards the reversing control cavity 254, a connecting liquid path between the front cavity 252 of the cutoff valve and the rear cavity 253 of the cutoff valve is opened, and the pressure liquid at the pressure oil port P can enter the rear pressure oil channel G through the pressure compensator 1 and the front pressure oil channel F and then enters the energy storage oil channel E through the check valve 3 to charge the energy accumulator 9. As the charging progresses, the pressure at the accumulator connection port AC gradually increases, as does the pressure of the fluid within the reversing control chamber 254. When the pressure of the fluid in the reversing control cavity 254 is greater than the set value, the thrust of the pressurized fluid on the reversing valve rod 21 is greater than the sum of the elastic force of the reversing spring 23 and the pressure generated by the pilot hydraulic oil, at this time, the reversing valve rod 21 slides towards the direction of the reversing spring cavity 251, the connecting fluid path between the front cut-off valve cavity 252 and the rear cut-off valve cavity 253 is cut off, the accumulator 9 stops filling the fluid, and the pressure at the accumulator connecting port AC is prevented from further increasing.

One embodiment of the hydraulic brake system of the present invention includes a system pump source, an accumulator 9, a hydraulic parking brake, and an accumulator charge valve of any embodiment of the present invention. The system pump source is connected with the pressure oil port P, pressure liquid is pumped into the pressure oil port P of the accumulator charging valve, the accumulator 9 is connected to an accumulator connector AC of the accumulator charging valve, the pressure liquid is flushed according to set pressure, the pressure liquid requirement of the hydraulic parking brake is guaranteed, the pressure of the pressure liquid is not more than the maximum bearing pressure of the brake cylinder, and the use safety of the hydraulic parking brake is guaranteed. The hydraulic driving oil port of the hydraulic parking brake is connected with the braking oil port Pi of the accumulator liquid charging valve so as to obtain pressure liquid with stable pressure from the accumulator 9, ensure that the pressure of the pressure liquid is not influenced by the starting and stopping of a system pump source and the pressure fluctuation at the pressure oil port P, and ensure the reliability of the parking brake.

In the description of the present invention, reference to the description of the terms "one embodiment," "some embodiments," "a specific embodiment," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In the present disclosure, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, numerous simple modifications can be made to the technical solution of the invention, including combinations of the individual specific technical features in any suitable way. The invention is not described in detail in order to avoid unnecessary repetition. Such simple modifications and combinations should be considered within the scope of the present disclosure as well.