CN212928165U - A pressure limiting valve device, pressure regulating plunger and hydraulic pump - Google Patents

Abstract

The application discloses a pressure limiting valve device, a pressure regulating plunger and a hydraulic pump, wherein the pressure limiting valve device comprises a plunger accommodating cavity arranged in a machine body, and the pressure regulating plunger and an elastic component which are arranged in the plunger accommodating cavity; the pressure regulating plunger comprises a first head part, a second head part and a connecting part connected between the first head part and the second head part; the outer wall surfaces of the first head part and the second head part are respectively matched with the inner wall surface of the plunger accommodating cavity; the first head part separates a pressure feedback cavity and a high-pressure oil cavity which are arranged in the plunger accommodating cavity; the second head part separates a high-pressure oil chamber and a low-pressure oil chamber which are arranged in the plunger accommodating chamber; one end of the elastic component is abutted against the bottom of the second head part, and the other end of the elastic component is abutted against the inner wall of the low-pressure oil cavity; the side wall of the first head part is provided with an oil inlet, the bottom of the second head part, which is positioned in the low-pressure oil cavity, is provided with an oil outlet, and the oil inlet is connected with the oil outlet through an oil duct arranged in the pressure regulating plunger; the pressure feedback cavity is communicated with an oil pressure position needing to obtain oil pressure feedback.

Description

A pressure limiting valve device, pressure regulating plunger and hydraulic pump

technical field

The present application specifically relates to a pressure limiting valve device, a pressure regulating plunger, and a hydraulic pump.

Background technique

A pump is a machine that transports fluid or pressurizes the fluid. For example, in order to ensure the normal operation of the engine and gearbox, the oil pump needs to provide a stable and reliable supply of lubricating oil with a certain pressure.

In the prior art, a pressure limiting valve device is usually designed on the oil pump to maintain a constant oil pressure. The pressure limiting valve device is designed with a pressure regulating plunger, and the position of the pressure regulating plunger varies with different feedback pressures. Move in the plunger accommodating cavity, so that there are different degrees of penetration between the high-pressure oil cavity and the low-pressure oil cavity, thereby changing the output oil pressure, so that the output oil pressure of the oil pump is within the required range, so as to achieve the purpose of pressure regulation .

However, in order to achieve this effect, in the design, there must be an appropriate gap between the pressure regulating plunger and the plunger accommodating cavity, which leads to the gap between the high-pressure oil cavity and the pressure feedback cavity inside the pump body. The situation where the leaked oil enters the pressure feedback chamber, and the leaked high-pressure oil will interfere with the normal pressure feedback of the pressure feedback chamber.

Therefore, it is necessary to improve the structure of the existing pressure limiting device, so that it can not only meet the normal operation of the pump, but also prevent the leakage of high-pressure liquid.

Utility model content

The present application provides a pressure limiting valve device, which solves the problem in the prior art that the leakage of high-pressure oil into the pressure feedback chamber affects the normal operation of the oil pump. The present application further provides a pressure regulating plunger and a hydraulic pump.

The present application provides a pressure limiting valve device, comprising: a plunger accommodating cavity disposed in a body, and a pressure regulating plunger and an elastic component disposed inside the plunger accommodating cavity;

The pressure regulating plunger includes a first head, a second head, and a connecting part connected between the first head and the second head; the outer wall surfaces of the first head and the second head are respectively connected with The inner wall surfaces of the plunger accommodating cavity are matched; the first head part separates the pressure feedback cavity and the high-pressure oil cavity arranged in the plunger accommodating cavity; the second head part is arranged in the column The high-pressure oil chamber and the low-pressure oil chamber in the plug accommodating chamber are separated; one end of the elastic member abuts against the bottom of the second head, and the other end abuts against the inner wall of the low-pressure oil chamber;

The side wall of the first head is provided with an oil inlet, the second head is located at the bottom of the low pressure oil chamber and is provided with an oil outlet, and the oil inlet and the oil outlet pass through the pressure regulating The oil passages arranged inside the plunger are connected; the pressure feedback chamber communicates with the oil pressure position that needs to obtain oil pressure feedback.

Preferably, the elastic member and the pressure regulating plunger are arranged along the axial direction of the plunger accommodating cavity.

Preferably, the oil passages provided inside the pressure regulating plunger include: an oil inlet oil passage and an oil outlet oil passage that are communicated with each other; wherein,

The oil inlet oil passage is arranged at the first head position along the radial direction of the plunger accommodating cavity, and communicates with the oil inlet port;

The oil outlet oil passage is arranged at the position of the connecting portion along the axial direction of the plunger accommodating cavity; and communicates with the oil outlet.

Preferably, the side wall surface of the first head close to the high-pressure oil chamber abuts the inner wall surface of the plunger accommodating chamber;

The first head side wall surface abutting against the inner wall surface of the plunger accommodating cavity includes at least a pair of symmetrically arranged oil inlets, and each pair of oil inlets corresponds to an oil inlet channel.

Preferably, the side wall surface of the first head is provided with an annular groove, and the symmetrically arranged oil inlet is provided in the annular groove.

The present application further provides a pressure regulating plunger, the pressure regulating plunger comprising a first head, a second head and a connecting part connected between the first head and the second head;

The side wall of the first head is provided with an oil inlet, the bottom of the second head is provided with an oil outlet, and the oil inlet and the oil outlet are arranged inside the pressure regulating plunger connected to the oil passages.

Preferably, the oil passages provided inside the pressure regulating plunger include: an oil inlet oil passage and an oil outlet oil passage that are communicated with each other; wherein,

The oil inlet oil passage is arranged at the position of the first head along the radial direction of the first head, and communicates with the oil inlet;

The oil outlet oil passage is arranged at the position of the connection portion along the axial direction of the connection portion; and communicates with the oil outlet.

Preferably, the side wall surface of the first head includes at least a pair of symmetrically arranged oil inlets, and each pair of oil inlets corresponds to an oil inlet channel.

Preferably, the side wall surface of the first head is provided with an annular groove, and the symmetrically arranged oil inlet is provided in the annular groove. The application also provides a hydraulic pump, comprising: a pump body and a plunger type pressure limiting device;

The inside of the pump body includes an oil inlet cavity and an oil outlet cavity;

The plunger-type pressure limiting device includes a plunger accommodating cavity, and the plunger accommodating cavity includes a low-pressure oil cavity, a high-pressure oil cavity and a pressure feedback cavity;

The oil inlet chamber is communicated with the low pressure oil chamber; the oil outlet chamber is communicated with the high pressure oil chamber and the oil outlet pipe arranged at the end of the pump body; The oil pressure position that obtains oil pressure feedback is connected;

The plunger-type pressure limiting device further includes a pressure regulating plunger and an elastic component arranged inside the plunger accommodating cavity;

The plunger type pressure limiting device includes: a plunger accommodating cavity arranged in the body, and a pressure regulating plunger and an elastic component arranged in the inside of the plunger accommodating cavity; the pressure regulating plunger comprises a first a head part, a second head part, and a connecting part connected between the first head part and the second head part; the outer wall surfaces of the first head part and the second head part are respectively connected with the inner wall surface of the plunger accommodating cavity Matching; the first head separates the pressure feedback chamber and the high-pressure oil chamber arranged in the plunger accommodating cavity; the second head separates the high-pressure oil cavity arranged in the plunger accommodating cavity is separated from the low-pressure oil chamber; one end of the elastic member abuts against the bottom of the second head, and the other end abuts against the inner wall of the low-pressure oil chamber; the side wall of the first head is provided with an oil inlet The second head is located at the bottom of the low-pressure oil chamber and is provided with an oil outlet, and the oil inlet and the oil outlet are connected through an oil passage provided inside the pressure regulating plunger.

Compared with the prior art, the present application has the following advantages:

The present application provides a pressure limiting valve device, comprising: a plunger accommodating cavity provided in the body, and a pressure regulating plunger and an elastic component disposed inside the plunger accommodating cavity; the pressure regulating plunger It includes a first head, a second head, and a connecting part connected between the first head and the second head; the outer wall surfaces of the first head and the second head are respectively accommodated with the plunger The inner wall of the cavity is matched; the first head part separates the pressure feedback cavity and the high-pressure oil cavity provided in the plunger accommodating cavity; the second head part separates the pressure feedback cavity provided in the plunger accommodating cavity from the high-pressure oil cavity; The high-pressure oil chamber and the low-pressure oil chamber are separated; one end of the elastic member abuts against the bottom of the second head, and the other end abuts against the inner wall of the low-pressure oil chamber; the side wall of the first head is provided with There is an oil inlet, and the second head is located at the bottom of the low-pressure oil cavity and is provided with an oil outlet, and the oil inlet and the oil outlet are connected through the oil passage provided inside the pressure regulating plunger; The pressure feedback chamber communicates with the oil pressure position that needs to obtain oil pressure feedback. The pressure-limiting valve device described in the present application abandons the original drawback that there must be an appropriate interval between the pressure-regulating plunger and the pump body. The oil in the gap between the head and the plunger accommodating cavity can return to the low-pressure oil cavity, which prevents the oil in the high-pressure oil cavity from leaking into the pressure feedback cavity, thereby avoiding the influence on the oil pressure control effect.

Description of drawings

1 is a schematic structural diagram of a pressure limiting valve device provided in a first embodiment of the present application;

FIG. 2 is a schematic structural diagram of a pressure regulating plunger inside the pressure limiting valve device provided in the first embodiment of the present application.

Detailed ways

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described here, and those skilled in the art can make similar promotions without violating the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below. .

In the present application, a pressure limiting valve device, a pressure regulating plunger and a hydraulic pump are respectively provided. Detailed descriptions will be made one by one in the following examples.

First, the structure of the pressure limiting valve device according to the first embodiment of the present application will be introduced with reference to FIG. 1 and FIG. 2 .

As shown in FIG. 1 , it is the plunger-type pressure limiting device according to the first embodiment of the application, including a plunger accommodating cavity 107 arranged in the body 101 , and a plunger accommodating cavity 107 arranged inside the plunger accommodating cavity 107 The pressure regulating plunger 102 and the elastic member 103.

The plunger accommodating cavity 107 is divided into three areas, namely: a low pressure oil cavity 104 , a high pressure oil cavity 105 , and a pressure feedback cavity 106 .

In the first embodiment of the present application, the body 101 specifically refers to a casing that provides an accommodating cavity and an oil circuit for the entire mechanism; the body 101 is the assembly basis of the entire device.

The pressure limiting valve device provided in this embodiment may be used for a hydraulic pump in some scenarios. The main function of the hydraulic pump is to increase the pressure of the liquid, thereby conveying the liquid (such as oil, lubricating oil), and the function of the pump is to provide a stable and suitable output pressure for the liquid to be conveyed. For example, in the engine and gearbox, since a certain amount of lubricating oil is required to cool the friction pair and gear pair, the oil pump needs to provide a stable lubricating oil supply with a certain pressure. In order to meet such demands, it is necessary to be able to automatically adjust the pumping oil pressure of the pump; the pressure limiting valve device provided in this embodiment helps to realize this function.

In order to realize the above adjustment function, the pressure feedback chamber 106 communicates with the oil pressure position that needs to obtain oil pressure feedback. Specifically, the oil pressure position obtained by obtaining the oil pressure feedback is the oil pressure at the end of the oil circuit.

In the first embodiment of the present application, the pressure feedback chamber 106 changes with the pressure of the oil pressure position, and the two ends of the elastic member 103 are respectively connected to the bottom of the pressure regulating plunger 102 and the column The inner walls of the plug accommodating cavity 101 are connected to each other. Since the pressure generated by the pressure feedback chamber 106 and the oil pressure position is the same, the pressure feedback chamber 106 can provide the pressure to the pressure regulating plunger 102 along the axial direction of the plunger accommodating cavity, and this The pressure can reflect the pressure change of the oil pressure position. When the pump is working normally, that is, when the pressure of the liquid at the pump outlet is in a preset stable state, the oil pressure on each part of the pressure regulating plunger 102 and the elastic force provided by the elastic member 103 make the The pressure regulating plunger 102 is in a balanced state in the plunger accommodating cavity 101. Once the pressure at the pump outlet increases, the preset stable state is changed, and the pressure at the oil pressure position of the oil pressure feedback is obtained. will also increase, and the pressure of the oil pressure position of the oil pressure feedback acts on the pressure regulating plunger 102 through the pressure feedback cavity 106 until the equilibrium state of the pressure regulating plunger 102 in the plunger accommodating cavity 101 is broken, Change the position of the pressure regulating plunger 102 in the plunger accommodating cavity 101, so that the liquid in the high pressure oil cavity 105 flows into the low pressure oil cavity 104, so that the hydraulic pressure in the high pressure oil cavity 105 gradually decreases, Then, the hydraulic pressure at the pump outlet is gradually reduced until the hydraulic pressure at the pump outlet returns to a preset stable state.

Please refer to FIG. 2 , which is a schematic structural diagram of the pressure regulating plunger 102 disposed inside the plunger accommodating cavity 107 . The structure of the pressure limiting valve device proposed in the first embodiment of the present application will be introduced below in conjunction with the contents of FIG. 1 and FIG. 2 , so as to understand the working process of the device.

The pressure regulating plunger 102 includes a first head portion 1021, a second head portion 1022, and a connecting portion 1023 connected between the first head portion and the second head portion.

The functions of the pressure regulating plunger 102 are: 1. Separate the space in the plunger accommodating cavity 101 to form a low pressure oil cavity 104, a high pressure oil cavity 105 and a pressure feedback cavity 106; 2. The movement in 101 changes the pressure of the high-pressure oil chamber 105 .

In order to enable the pressure regulating plunger to achieve the above function, the outer walls of the first head 1021 and the second head 1022 are matched with the inner wall of the plunger accommodating cavity 101 respectively; A typical gap size range is, for example, 0.03mm to 0.007mm; in this matching manner, the pressure regulating plunger can be flexibly moved along the plunger accommodating cavity 101, and the low-pressure oil cavity can be realized under the cooperation of the oil film. 104 , isolation between the high pressure oil chamber 105 and the pressure feedback chamber 106 .

The first head 1021 separates the pressure feedback chamber 106 and the high-pressure oil chamber 105 arranged in the plunger accommodating cavity 101 ; the second head 1022 is arranged in the plunger accommodating cavity 101 The high pressure oil chamber 105 and the low pressure oil chamber 104 are separated.

As shown in FIG. 1 , one end of the elastic member 103 abuts against the bottom of the second head portion 1022 , and the other end abuts against the inner wall of the low-pressure oil chamber 104 . The axial arrangement of the plunger accommodating cavity.

When the pump is working normally, the elastic member 103 is used to balance the axial force exerted by the high pressure oil chamber 105 and the pressure feedback chamber 106 on the pressure regulating plunger 102, so that the pressure regulating plunger is at the The plunger accommodating cavity 101 is in a balanced state.

The side wall of the first head 1021 is provided with an oil inlet 201, the second head 1022 is located at the bottom of the low pressure oil chamber and is provided with an oil outlet 202, and the oil inlet 201 and the oil outlet 202 is connected through the oil passage provided inside the pressure regulating plunger 102 .

As shown in FIG. 2 , the oil passages provided inside the pressure regulating plunger 102 include: an oil inlet oil passage 2031 and an oil outlet oil passage 2032 which are communicated with each other.

The oil inlet oil passage 2031 is disposed at the position of the first head 1021 along the radial direction of the plunger accommodating cavity 101, and communicates with the oil inlet port 201;

The oil outlet oil passage 2032 is disposed at the position of the connecting portion 1023 along the axial direction of the plunger accommodating cavity 101 ; and communicates with the oil outlet port 202 .

The oil passage, the oil inlet 201 and the oil outlet 202 together form a liquid passage inside the pressure regulating plunger 102 .

In the first embodiment of the present application, the low-pressure oil chamber 104 communicates with the oil inlet chamber of the pump, and the high-pressure oil chamber 105 communicates with the oil outlet chamber of the pump. Before the pump is started, the oil inlet chamber of the pump will be filled with the liquid to be conveyed, and these liquids will enter the oil outlet chamber through the energy conversion of the pump, and then flow out through the oil passage that communicates with the oil outlet chamber. Therefore, the hydraulic pressure in the high-pressure oil chamber 105 is greater than the hydraulic pressure in the low-pressure oil chamber 104, and as mentioned above, the pressure feedback chamber 106 communicates with the end of the oil circuit. When the liquid flows out through the oil circuit, a certain energy loss will inevitably occur, so , the pressure of the pressure feedback chamber 106 will be lower than the pressure of the high-pressure oil chamber 105 and greater than the pressure of the low-pressure oil chamber 104 .

Since there is a pressure difference between the high-pressure oil chamber 105 and the pressure feedback chamber 106, and there is a gap between the first head 1021 and the inner wall of the plunger accommodating chamber 101, the liquid in the high-pressure oil chamber 105 will A small leak has occurred. However, whether it is the high-pressure oil chamber 105 or the pressure feedback chamber 106, the internal pressure is greater than the low-pressure oil chamber 104. Therefore, the oil leaked from the high-pressure oil chamber 105 will eventually flow into the oil inlet 201 and pass through the adjustment. The oil passage provided inside the pressure plunger 102 flows back to the low pressure oil chamber 104 . The first embodiment of the present application fully considers the pressure difference in each area of the plunger accommodating cavity 101 , and by arranging an oil passage running through the pressure regulating plunger 102 , the leakage of oil from the high-pressure oil cavity 105 into the pressure feedback cavity is avoided. 106, the problem that affects the oil pressure control effect.

In addition, in order to facilitate the oil inlet to collect the leaked oil, the side wall surface of the first head 1031 is further provided with an annular groove, and the symmetrically arranged oil inlet 201 is arranged in the annular groove .

It should be noted that the design of the oil inlet and the oil inlet channel shown above is a preferred embodiment of the device, and different structures can be used in other embodiments, for example: the oil inlet and the oil inlet The channels may be designed in multiple numbers, that is, the first head side wall surface abutting against the inner wall surface of the plunger accommodating cavity may include at least a pair of symmetrically arranged oil inlets, and each pair of oil inlets corresponds to one oil inlet oil passage. In addition, each pair of oil inlets can be arranged on the same peripheral surface of the first head at the same time, or can be staggered from each other along the axial direction of the plunger accommodating cavity, and arranged in sequence on the first head. side wall. These are simple changes to the structure of the plunger-type pressure limiting device described in the first embodiment of the present application, do not deviate from the core of the present application, and are all within the protection scope of the present application.

In addition, the pressure limiting valve device provided in the first embodiment of the present application can not only be applied to any hydraulic pump design to meet the requirements of the hydraulic pump for its own pressure control in specific applications, but also can be used as an independent unit, Used in some hydraulic systems to meet the pressure stability control of the system.

To sum up, the pressure-limiting valve device provided by the first embodiment of the present application eliminates the disadvantage that there must be an appropriate interval between the original pressure-regulating plunger and the pump body in structure. The oil channel method enables the oil flowing from the high-pressure oil chamber into the gap between the first head and the plunger accommodating chamber to flow back into the low-pressure oil chamber, preventing the oil in the high-pressure oil chamber from leaking into the pressure feedback chamber, thereby preventing the oil from leaking into the pressure feedback chamber. The influence on the oil pressure control effect is avoided.

In the above embodiment, a pressure limiting valve device is provided. Correspondingly, the second embodiment of the present application also provides a pressure regulating plunger. Since the second embodiment is basically similar to the above first embodiment, so The description is relatively simple, and reference may be made to the partial description of the first embodiment for related parts, and the embodiments of the pressure regulating plunger described below are only illustrative.

The pressure regulating plunger provided by the second embodiment of the present application includes a first head, a second head, and a connecting part connected between the first head and the second head;

The side wall of the first head is provided with an oil inlet, the bottom of the second head is provided with an oil outlet, and the oil inlet and the oil outlet are arranged inside the pressure regulating plunger connected to the oil passages.

Preferably, the oil passage provided inside the pressure regulating plunger comprises: an oil inlet oil passage and an oil outlet oil passage which are communicated with each other; wherein, the oil inlet oil passage is arranged at the location along the radial direction of the first head. The first head is located at the position of the first head and communicated with the oil inlet; the oil outlet oil passage is arranged at the position of the connection part along the axial direction of the connection part; and communicated with the oil outlet.

Preferably, the side wall surface of the first head includes at least a pair of symmetrically arranged oil inlets, and each pair of oil inlets corresponds to an oil inlet channel.

Preferably, the side wall surface of the first head is provided with an annular groove, and the symmetrically arranged oil inlet is provided in the annular groove.

The third embodiment of the present application also provides a hydraulic pump. The hydraulic pump described in the third embodiment of the present application is basically similar to the above-mentioned first embodiment, so the description is relatively simple. For relevant details, please refer to the partial description of the first embodiment. That is, the oil pump embodiments described below are merely illustrative.

The hydraulic pump provided by the third embodiment of the present application includes: a pump body and a plunger type pressure limiting device.

The inside of the pump body includes an oil inlet cavity and an oil outlet cavity;

The plunger-type pressure limiting device includes a plunger accommodating cavity, and the plunger accommodating cavity includes a low-pressure oil cavity, a high-pressure oil cavity and a pressure feedback cavity;

The oil inlet chamber is communicated with the low pressure oil chamber; the oil outlet chamber is communicated with the high pressure oil chamber and the oil outlet pipe arranged at the end of the pump body; The oil pressure position that obtains oil pressure feedback is connected.

The inside of the pump body is usually provided with a gear for increasing the liquid pressure. Before the hydraulic pump is started, the oil inlet cavity inside the pump body will be filled with the liquid to be conveyed. The oil inlet chamber is thrown to the oil outlet chamber, and obtains energy, and flows out from the oil outlet pipe at a higher pressure, and enters the required place.

It should be noted that the internal structure and working principle of the hydraulic pump described in the third embodiment of the present application are not limited to the high-speed rotation of the liquid driven by gears. Corresponding to different working principles, for example, a rotor can also be arranged inside the pump body, and the rotor includes an inner rotor and an outer rotor; wherein, the contour lines of each gear of the inner and outer rotors can always be in point contact with each other, so that the inner and outer rotors can always be in point contact with each other. , A plurality of working chambers will be formed between the outer rotors. With the rotation of the rotor, the volume of each working chamber will change. If the working chamber communicated with the oil inlet chamber becomes larger, the liquid will be sucked into the pump body. , correspondingly, if the working chamber communicated with the oil outlet chamber shrinks, the liquid will be pumped out. This also belongs to a simple transformation of the internal structure of the hydraulic pump body described in the third embodiment of the present application, does not deviate from the core of the present application, and falls within the protection scope of the present application.

In addition, the plunger-type pressure limiting device further includes a pressure regulating plunger and an elastic member arranged inside the plunger accommodating cavity.

The pressure regulating plunger includes a first head, a second head, and a connecting part connected between the first head and the second head; the outer wall surfaces of the first head and the second head are respectively connected with The inner wall surfaces of the plunger accommodating cavity are matched; the first head part separates the pressure feedback cavity and the high-pressure oil cavity arranged in the plunger accommodating cavity; the second head part is arranged in the column The high-pressure oil chamber and the low-pressure oil chamber in the plug accommodating chamber are separated; one end of the elastic member abuts against the bottom of the second head, and the other end abuts against the inner wall of the low-pressure oil chamber;

The side wall of the first head is provided with an oil inlet, the second head is located at the bottom of the low pressure oil chamber and is provided with an oil outlet, and the oil inlet and the oil outlet pass through the pressure regulating The oil passages provided inside the plunger are connected.

Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the present application The scope of protection shall be subject to the scope defined by the claims of this application.

Claims (10)

1. A pressure limiting valve apparatus, comprising: the pressure regulating plunger piston and the elastic component are arranged in the plunger piston accommodating cavity;

the pressure regulating plunger comprises a first head part, a second head part and a connecting part connected between the first head part and the second head part; the outer wall surfaces of the first head part and the second head part are respectively matched with the inner wall surface of the plunger accommodating cavity; the first head part separates a pressure feedback cavity and a high-pressure oil cavity which are arranged in the plunger accommodating cavity; the second head portion separates a high-pressure oil chamber and a low-pressure oil chamber provided in the plunger accommodating chamber; one end of the elastic component is abutted against the bottom of the second head part, and the other end of the elastic component is abutted against the inner wall of the low-pressure oil cavity;

the side wall of the first head is provided with an oil inlet, the bottom of the second head, which is positioned in the low-pressure oil cavity, is provided with an oil outlet, and the oil inlet is connected with the oil outlet through an oil duct arranged in the pressure regulating plunger; the pressure feedback cavity is communicated with an oil pressure position needing to obtain oil pressure feedback.

2. The pressure limiting valve assembly as recited in claim 1 wherein the resilient member and pressure regulating plunger are disposed axially of the plunger receiving cavity.

3. The pressure limiting valve assembly as recited in claim 2 wherein the oil passage provided within the pressure regulating plunger comprises: the oil inlet oil duct and the oil outlet oil duct are communicated with each other; wherein,

the oil inlet oil duct is arranged at the first head part along the radial direction of the plunger accommodating cavity and is communicated with the oil inlet;

the oil outlet passage is arranged at the position of the connecting part along the axial direction of the plunger accommodating cavity; and is communicated with the oil outlet.

4. The pressure limiting valve device as recited in claim 3 wherein a side wall surface of the first head portion that is close to the high-pressure oil chamber abuts against an inner wall surface of the plunger accommodating chamber;

the side wall surface of the first head abutting against the inner wall surface of the plunger accommodating cavity at least comprises a pair of symmetrically arranged oil inlets, and each pair of oil inlets corresponds to one oil inlet duct.

5. A pressure limiting valve arrangement as claimed in claim 4 wherein the side wall surface of the first head portion is provided with an annular groove in which the symmetrically disposed oil inlets are disposed.

6. A pressure regulating plunger, comprising a first head, a second head, and a connecting portion connected between the first head and the second head;

the side wall of the first head is provided with an oil inlet, the bottom of the second head is provided with an oil outlet, and the oil inlet is connected with the oil outlet through an oil duct arranged in the pressure regulating plunger.

7. The pressure regulating plunger of claim 6, wherein the oil passages provided therein comprise: the oil inlet oil duct and the oil outlet oil duct are communicated with each other; wherein,

the oil inlet oil duct is arranged at the first head part along the radial direction of the first head part and is communicated with the oil inlet;

the oil outlet passage is arranged at the position of the connecting part along the axial direction of the connecting part; and is communicated with the oil outlet.

8. The pressure regulating plunger of claim 7, wherein the side wall surface of the first head portion at least comprises a pair of symmetrically arranged oil inlets, and each pair of oil inlets corresponds to one oil inlet channel.

9. The pressure regulating plunger of claim 8, wherein the sidewall surface of the first head portion is provided with an annular recess, and the symmetrically disposed oil inlets are disposed in the annular recess.

10. A hydraulic pump, comprising: a pump body and a plunger type pressure limiting device;

the pump body comprises an oil inlet cavity and an oil outlet cavity;

the plunger type pressure limiting device comprises a plunger containing cavity, and the plunger containing cavity comprises a low-pressure oil cavity, a high-pressure oil cavity and a pressure feedback cavity;

the oil inlet cavity is communicated with the low-pressure oil cavity; the oil outlet cavity is communicated with the high-pressure oil cavity and an oil outlet pipe arranged at the tail end of the pump body; the pressure feedback cavity is communicated with an oil pressure position which is arranged at the tail end of an oil way of the oil outlet pipe and obtains oil pressure feedback;

the plunger type pressure limiting device also comprises a pressure regulating plunger and an elastic component which are arranged in the plunger accommodating cavity;

the plunger type pressure limiting device comprises: the pressure regulating plunger and the elastic component are arranged in the plunger accommodating cavity; the pressure regulating plunger comprises a first head part, a second head part and a connecting part connected between the first head part and the second head part; the outer wall surfaces of the first head part and the second head part are respectively matched with the inner wall surface of the plunger accommodating cavity; the first head part separates a pressure feedback cavity and a high-pressure oil cavity which are arranged in the plunger accommodating cavity; the second head portion separates a high-pressure oil chamber and a low-pressure oil chamber provided in the plunger accommodating chamber; one end of the elastic component is abutted against the bottom of the second head part, and the other end of the elastic component is abutted against the inner wall of the low-pressure oil cavity; the side wall of the first head is provided with an oil inlet, the bottom of the second head, which is located in the low-pressure oil cavity, is provided with an oil outlet, and the oil inlet is connected with the oil outlet through an oil duct arranged in the pressure regulating plunger.

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