CN212717427U - Variable power valve group, variable power control device and hydraulic system - Google Patents

Abstract

The utility model relates to a hydraulic system field discloses a change power valves, change power controlling means and hydraulic system. The variable power valve group comprises a valve body and is arranged in the valve body: the overflow valve core is arranged in the valve body in a sliding manner along the axial direction; the variable power valve is characterized in that a variable power valve core is arranged at one end of an overflow valve core in an axial sliding mode and is abutted against the overflow valve core, and the inlet oil pressure of the variable power valve is determined according to the required power of an engine on the engineering vehicle; and the power elastic piece is arranged at the other end of the overflow valve core, one end of the power elastic piece is fixed relative to the valve body, and the other end of the power elastic piece is abutted against the valve sleeve through the power valve seat. The utility model discloses set up the variable power valve in one side of overflow valve core back to power elastic component, adjust the import oil pressure of variable power valve according to the demand power of engine on the engineering vehicle to adjust the overflow valve core position of overflow valve, and make the overflow valve core establish the balance under the combined action of variable power valve core and power elastic component, realize the variable power regulation of variable power valves.

Description

Variable power valve group, variable power control device and hydraulic system

Technical Field

The utility model relates to a hydraulic system field especially relates to a change power valves, change power controlling means and hydraulic system.

Background

In the open type hydraulic system, the output power of the variable pump is the product of the output flow Q of the pump and the pressure P of the oil outlet of the variable pump, and since the pressure P of the oil outlet of the variable pump changes along with the change of the load, in order to stabilize the output power, the output flow Q of the variable pump needs to be controlled by a constant power control device, so that the product of Q and P is kept unchanged, and the output power is in a constant state.

The current power control device usually adopts a "double-fold line" type constant power control, which is a control mode similar to constant power. The power control method cannot feed back the power requirement of the electric control engine to the power setting requirement of the variable pump according to the actual working condition, so that certain energy waste inevitably exists in the double-fold line type constant power control, the requirement of saving is not met, and the use cost of customers is increased.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a become power valves, become power controlling means and hydraulic system can the energy saving, reduces use cost.

To achieve the purpose, the utility model adopts the following technical proposal:

the utility model provides a change power valves, includes the valve body, and locate in the valve body:

the overflow valve core is arranged in the valve body in a sliding manner along the axial direction;

the variable power valve is characterized in that a variable power valve core of the variable power valve is arranged at one end of the overflow valve core in an axial sliding manner and is abutted against the overflow valve core, and the inlet oil pressure of the variable power valve is determined according to the required power of an engine on an engineering vehicle;

and the power elastic piece is arranged at the other end of the overflow valve core, one end of the power elastic piece is fixed relative to the valve body, and the other end of the power elastic piece can be abutted against the overflow valve core through a power valve seat.

As a preferable technical solution of the variable power valve group, the variable power valve group further comprises:

the valve sleeve is arranged in the valve body in an axial sliding manner and is used for being connected to a swash plate of the variable displacement pump, and the overflow valve core is arranged in the valve sleeve in a sliding manner;

the discharge elastic piece and the power elastic piece are arranged at the same end of the overflow valve core, one end of the discharge elastic piece is abutted against the inner wall of the valve body, the other end of the discharge elastic piece can be abutted against the valve sleeve through a discharge valve seat, and the discharge valve seat is in sliding connection with the power valve seat.

As a preferred technical solution of the variable power valve group, the relief valve core includes a first portion, a second portion and a third portion, which are sequentially arranged in an axial direction, an outer diameter of the second portion is smaller than an outer diameter of the first portion and smaller than an outer diameter of the third portion, so that a high-pressure oil inlet cavity is formed between the relief valve core and the valve sleeve, and a contact area between the first portion and the high-pressure oil inlet cavity is smaller than a contact area between the third portion and the high-pressure oil inlet cavity;

the overflow valve core can selectively enable the high-pressure oil inlet cavity to be communicated with the low-pressure oil outlet cavity on the valve body or enable the high-pressure oil inlet cavity to be completely disconnected with the low-pressure oil outlet cavity.

As a preferable technical solution of the variable power valve group, a power adjusting rod capable of moving or fixing axially relative to the valve body is arranged on the valve body, the power adjusting rod is arranged on a side of the power elastic member facing away from the overflow valve core, and one end of the power elastic member abuts against the power adjusting rod.

As a preferred technical scheme of the variable power valve group, the valve body is provided with a power pressure regulating hole, a buffer throttling hole and a valve core mounting hole which are sequentially communicated along the axial direction of the valve body, and the aperture of the buffer throttling hole is smaller than that of the power pressure regulating hole and smaller than that of the valve core mounting hole;

the variable power valve core is arranged in the valve core mounting hole in a sliding mode.

The utility model also provides a variable power controlling means, including foretell variable power valves.

As a preferred technical scheme of the variable power control device, the variable power control device further comprises a variable pump, a load sensitive component and a servo variable oil cylinder;

a rodless servo cavity of the servo variable oil cylinder can be selectively communicated with an oil outlet of the variable pump or a hydraulic oil tank through the load sensitive assembly;

the variable power valve group comprises a valve sleeve and a displacement elastic part, wherein the swash plate is connected with the valve sleeve and can push the valve sleeve to axially move relative to the valve body, so that the valve sleeve keeps balance under the combined action of the swash plate and the displacement elastic part.

As a preferable technical solution of the variable power control device, the load sensing assembly includes:

the load sensitive valve comprises a first P port, a first T port, a first working oil port, a first pilot control oil port and a second pilot control oil port, the first P port is communicated with an oil outlet of the variable pump, the first T port is communicated with the hydraulic oil tank, and the first working oil port is communicated with the rodless servo cavity; the first working oil port can be selectively communicated with the first P port or the first T port; the first pilot control oil port is communicated with an oil outlet of the variable pump;

and the second pilot control oil port and a return spring of the load sensitive valve are positioned on the same side, an oil outlet of the variable pump is communicated with an oil inlet of the flow control valve, and an oil outlet of the flow control valve is simultaneously communicated with the second pilot control oil port and the load.

As a preferred technical scheme of the variable power control device, the variable power control device further comprises a pressure cut-off valve, wherein the pressure cut-off valve comprises a second P port, a second T port and a second working oil port, the second P port is communicated with an oil outlet of the variable pump, the second T port is communicated with the hydraulic oil tank, the second working oil port is communicated with the rodless servo cavity, and the first working oil port is communicated with the second P port; a pilot control oil port of the pressure cut-off valve is communicated with an oil outlet of the variable pump;

the second working oil port can be selectively communicated with the second P port or the second T port.

The utility model also provides a hydraulic system, including foretell variable power controlling means.

The utility model has the advantages that: the utility model discloses set up the variable power valve in one side of overflow valve core back to power elastic component, adjust the import oil pressure of variable power valve according to the demand power of engine on the engineering vehicle, act on the effort of overflow valve case with changing the power valve case, adjust the position of the overflow valve case of overflow valve, and make the overflow valve case establish the balance under the combined action of variable power valve case and power elastic component, realize the variable power regulation of variable power valves, the energy waste has been avoided, use cost is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

Fig. 1 is a hydraulic schematic diagram of a variable power control device according to an embodiment of the present invention;

fig. 2 is a cross-sectional view of a variable power valve set provided by the embodiment of the present invention.

In the figure:

1. a variable displacement pump; 11. a swash plate;

2. an overflow valve; 211. a valve body; 212. a first valve cover; 2121. a power pressure regulating hole; 2122. a buffer orifice; 2123. a valve core mounting hole; 213. a second valve cover; 22. an overflow valve core; 221. a first part; 222. a second section; 223. a third section; 231. a high pressure oil inlet cavity; 232. a low pressure oil outlet cavity; 24. a valve housing; 251. a power spring; 252. a power valve seat; 261. a displacement spring; 262. a displacement valve seat; 27. a power regulating lever; 28. a shifting fork; 29. a buffer spring;

3. a variable power valve core;

4. a servo variable cylinder; 41. a rodless servo cavity;

51. a load sensitive valve; 52. a flow control valve; 53. a first throttling unit; 54. a second throttling unit; 55. a third throttling unit;

6. a pressure shut-off valve;

7. resetting the oil cylinder; 71. the elastic member is reset.

Detailed Description

In order to make the technical problem solved by the present invention, the technical solution adopted by the present invention and the technical effect achieved by the present invention clearer, the technical solution of the present invention will be further explained by combining the drawings and by means of the specific implementation manner. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements related to the present invention are shown in the drawings.

As shown in fig. 1, the present embodiment provides a variable power control device, which includes a hydraulic pump, an overflow valve 2, a load sensing assembly, a servo variable cylinder 4 and a hydraulic oil tank, wherein a rodless servo cavity 41 of the servo variable cylinder 4 can be selectively communicated with an oil outlet of the variable pump 1 or communicated with the hydraulic oil tank through the load sensing assembly; the piston rod of the servo variable oil cylinder 4 is connected with the swash plate 11 of the variable pump 1, the oil inlet of the overflow valve 2 is communicated with the oil outlet of the variable pump 1, the oil outlet of the overflow valve 2 is communicated with the hydraulic oil tank, and the piston rod of the servo variable oil cylinder 4 can also adjust the compression amount of the displacement elastic part 261 of the overflow valve 2, so that the overflow pressure of the overflow valve 2 is matched with the system pressure.

Specifically, the load sensitive assembly includes a load sensitive valve 51 and a flow control valve 52, the load sensitive valve 51 includes two pilot control oil ports, which are a first pilot control oil port and a second pilot control oil port, respectively, wherein the second pilot control oil port and a return spring of the load sensitive valve 51 are located on the same side; the oil outlet of the variable pump 1 is directly communicated with the first pilot control oil port, the oil outlet of the variable pump 1 is communicated with the oil inlet of the flow control valve 52, and the oil outlet of the flow control valve 52 is simultaneously communicated with the second pilot control oil port and the load.

In this embodiment, the load-sensitive valve 51 is a two-position three-way directional valve, and includes a first P port, a first T port, and a first working oil port, where the first P port is communicated with the oil outlet of the variable displacement pump 1, the first T port is communicated with the hydraulic oil tank, the first working oil port is communicated with the rodless servo chamber 41, and the first working oil port can be selectively communicated with the first P port or the first T port. Specifically, the load sensitive valve 51 has a left position and a right position, when the load sensitive valve 51 is in the left position, the first P port is communicated with the first working oil port, and when the load sensitive valve 51 is in the right position, the first T port is communicated with the first working oil port. Preferably, the load sensitive valve 51 is a proportional valve.

The variable power control device can realize the displacement adjustment of the variable pump 1 according to the load change, namely the constant power adjustment. The process of the constant power adjustment by the variable power control device will be briefly described below, taking the decrease in the opening degree of the flow rate control valve 52 as an example.

The opening degree of the flow control valve 52 is reduced, the pressure difference between the inlet and the outlet of the flow control valve 52 is increased, the valve core of the load sensitive valve 51 moves to the right, the load sensitive valve 51 is switched to the left position, the oil outlet of the variable pump 1 is communicated with the rodless servo cavity 41, the piston rod of the servo variable oil cylinder 4 moves to the left, the swash plate 11 rotates anticlockwise, and the displacement of the variable pump 1 is reduced; at the same time, the piston rod of the servo variable cylinder 4 will cause the displacement elastic member 261 to be further compressed, and the opening pressure of the relief valve 2 is increased so that the opening pressure of the relief valve 2 matches the system pressure.

Further, in order to reduce the impact of the load change on the second pilot-controlled port, in the present embodiment, the outlet of the flow control valve 52 communicates with the second pilot-controlled port through the first throttle unit 53. The first throttle unit 53 may be an orifice or a throttle valve.

Further, the variable power control device further comprises a pressure cut-off valve 6, and a pilot control oil port of the pressure cut-off valve 6 is communicated with an oil outlet of the variable displacement pump 1. In this embodiment, the pressure cut-off valve 6 is a two-position three-way reversing valve, and includes a second P port, a second T port, and a second working oil port, the second P port is communicated with the oil outlet of the variable displacement pump 1, the second T port is communicated with the hydraulic oil tank, the second working oil port is communicated with the rodless servo chamber 41, and the first working oil port is communicated with the second T port; the second working oil port is selectively communicated with the second P port or the second T port.

Specifically, the pressure cut-off valve 6 has two states, which are respectively a left position and a right position, when the pressure cut-off valve 6 is in the left position, the second P port is communicated with the second working oil port, and when the pressure cut-off valve 6 is in the right position, the second T port is communicated with the second working oil port. Normally, the pressure cut-off valve 6 is in the right position under the action of the oil pressure of the pilot control port and the self-return spring.

When the outlet pressure of the variable pump 1 is increased to the preset cut-off oil pressure, the pressure cut-off valve 6 is switched from the right position to the left position, the oil outlet of the variable pump 1 is communicated with the rodless servo cavity 41 to push the piston rod of the servo variable oil cylinder 4 to move left, so that the swash plate 11 rotates anticlockwise to gradually reduce the displacement of the variable pump 1; after the oil pressure of the oil outlet of the variable displacement pump 1 is lower than the preset cut-off oil pressure, the pressure cut-off valve 6 will be automatically switched to the right position. Normally, in case of overload or malfunction, the pressure cut-off valve 6 may be switched to the left position to safely protect the variable displacement pump 1.

Further, the variable power control device further comprises a second throttling unit 54 and a third throttling unit 55, the first working oil port is communicated with the hydraulic oil tank through the second throttling unit 54, meanwhile, the first working oil port is also communicated with the rodless servo cavity 41 through the third throttling unit 55, and the rodless servo cavity 41 is communicated with the hydraulic oil tank through the third throttling unit 55 and the second throttling unit 54 in sequence. In the present embodiment, both the second throttling unit 54 and the third throttling unit 55 are orifices.

Further, the variable power control device further comprises a reset oil cylinder 7, a piston rod of the reset oil cylinder 7 is rotatably connected with the swash plate 11, a rodless cavity of the reset oil cylinder 7 is communicated with an oil outlet of the variable pump 1, and a reset elastic part 71 is arranged in the rodless cavity of the reset oil cylinder 7. Preferably, the return elastic member 71 is a spring.

Further, the variable power control device further comprises a variable power valve, wherein the inlet oil pressure of the variable power valve is determined according to the required power of an engine on the engineering vehicle, so that the initial position of the overflow valve core 22 of the overflow valve 2 is adjusted through the variable power valve core 3 of the variable power valve, and the power adjustment of the variable displacement pump 1 is realized.

This embodiment has still provided a variable power valves, and above-mentioned overflow valve 2 and the integrated setting of above-mentioned variable power valve have formed above-mentioned variable power valves, and the specific structure to become the power valves is briefly introduced below.

As shown in fig. 2, the variable power valve set includes a valve body, and a valve sleeve 24, an overflow valve core 22, a variable power valve core 3, a power elastic member 251 and a displacement elastic member 261 which are disposed in the valve body, wherein the valve sleeve 24 is disposed in the valve body in an axially sliding manner and connected to a swash plate 11 of the variable displacement pump 1. Specifically, the valve housing 24 is connected with a shifting fork 28, the shifting fork 28 is rotatably connected with the swash plate 11, and the shifting fork 28 is connected with a piston rod of the servo variable cylinder 4 to form an L-shaped structure. In this embodiment, the power elastic member 251 and the displacement elastic member 261 are both springs.

The overflow valve core 22 is arranged in the valve sleeve 24 in an axial sliding manner, the variable power valve core 3 is arranged at one end of the overflow valve core 22 in an axial sliding manner and is abutted against the overflow valve core 22, and the inlet oil pressure of the variable power valve is determined according to the required power of an engine on an engineering vehicle; the power elastic member 251 is arranged at the other end of the overflow valve core 22, one end of the power elastic member 251 is fixed relative to the valve body, and the other end is abutted against the overflow valve core 22 through the power valve seat 252; the displacement elastic element 261 and the power elastic element 251 are disposed at the same end of the overflow spool 22, one end of the displacement elastic element 261 abuts against the inner wall of the valve body, the other end abuts against the valve sleeve 24 through the displacement valve seat 262, and the displacement valve seat 262 is slidably connected with the power valve seat 252.

Specifically, the valve body includes a valve body 211 opened at both ends, and a first bonnet 212 and a second bonnet 213 provided at both ends of the valve body 211, and preferably, both the first bonnet 212 and the second bonnet 213 are threadedly coupled to the valve body 211. In order to improve the sealing performance when the first and second covers 212 and 213 are coupled to the valve body 211, sealing members, such as sealing rings, are disposed between the first and second covers 212 and 211 and between the second and second covers 213 and 211.

The first cover 212 and the variable power valve spool 3 are located at the same end of the valve body 211, and the second cover 213 and the power elastic member 251 are located at the same side of the valve body 211. The first valve cover 212 is provided with a power pressure regulating hole 2121, a buffer orifice 2122 and a valve core mounting hole 2123 which are sequentially communicated along the axial direction of the first valve cover, and the aperture of the buffer orifice 2122 is smaller than that of the power pressure regulating hole 2121 and smaller than that of the valve core mounting hole 2123; the variable power spool 3 is slidably disposed in the spool mounting hole 2123, and the damper orifice 2122 functions as a throttle damper to protect the variable power spool 3.

The oil pressure of the power pressure regulating hole 2121 is determined according to the required power of the engine, and specifically, an electric proportional pressure regulating valve may be disposed at an inlet of the power pressure regulating hole 2121 to regulate the current of the electric proportional pressure regulating valve according to the required power of the engine, so as to regulate the inlet oil pressure of the power pressure regulating hole 2121 to regulate the inlet oil pressure of the variable power valve, thereby realizing variable power regulation of the variable power valve bank, adapting the power of the variable pump 1 to the required power of the engine, and realizing energy saving.

The process of the variable power control of the variable power valve block will be briefly described below, taking an example in which the inlet oil pressure of the power pressure control hole 2121 is increased.

The inlet oil pressure of the power pressure regulating hole 2121 is increased, the oil pressure of the valve core mounting hole 2123 is increased, the variable power valve core 3 is pushed to move rightwards, the overflow valve core 22 is pushed to move rightwards, the power valve seat 252 is pushed to move rightwards by the overflow valve core 22, and the power elastic element 251 is further compressed, so that the overflow valve core 22 and the variable power valve core 3 are balanced under the action of the oil pressure in the power elastic element 251 and the valve core mounting hole 2123, the initial position of the overflow valve core 22 is changed, and the variable power regulation of the variable power valve group is realized.

When the piston rod of the servo variable cylinder 4 moves left and right, the swash plate 11 rotates to adjust the displacement of the variable pump 1, and the shifting fork 28 moves left and right under the action of the piston rod of the servo variable cylinder 4, so that the swash plate 11 is stabilized, and the constant power adjustment of the variable power control device is realized. The process of constant power adjustment will be briefly described below by taking the shift fork 28 to move to the right as an example.

The shift fork 28 moves to the right, the shift fork 28 pushes the valve sleeve 24 to move to the right, the valve sleeve 24 pushes the displacement elastic member 261 to be further compressed through the displacement valve seat 262, so that the valve sleeve 24 establishes an equilibrium under the force applied by the shift fork 28 and the force applied by the displacement elastic member 261 through the displacement valve seat 262, thereby stabilizing the displacement of the variable displacement pump 1.

Further, the relief valve core 22 comprises a first part 221, a second part 222 and a third part 223 which are sequentially arranged in the axial direction, wherein the outer diameter of the second part 222 is smaller than that of the first part 221 and smaller than that of the third part 223, so that a high-pressure oil inlet cavity 231 is formed between the relief valve core 22 and the valve sleeve 24; the first contact area of the third portion 223 contacting the high pressure oil inlet 231 is larger than the second contact area of the first portion 221 contacting the high pressure oil inlet 231, when the relief valve core 22 is in a balanced state, once the oil pressure in the high pressure oil inlet 231 is increased, the pressure acting on the relief valve core 22 is increased to the opening pressure of the relief valve 2, because the first contact area is different from the second contact area, the relief valve core 22 will move left and right, and the high pressure oil inlet 231 is selectively communicated with the low pressure oil outlet 232 on the valve body, or the high pressure oil inlet 231 is completely disconnected from the low pressure oil outlet 232. In this embodiment, the first portion 221 is disposed adjacent to the power variable valve body 3, and the third portion 223 is disposed adjacent to the power elastic member 251.

The low pressure discharge chamber 232 is communicated with the hydraulic oil tank, the high pressure oil inlet chamber 231 is communicated with the oil outlet of the variable displacement pump 1, and in the embodiment, the high pressure oil inlet chamber 231 is communicated with the outlet of the first throttling unit 53.

After the outlet oil pressure of the first throttling unit 53 is increased due to the load, the oil pressure of the high pressure oil inlet chamber 231 is increased, and when the oil pressure of the high pressure oil inlet chamber 231 is increased to increase the pressure acting on the overflow valve core 22 to the opening pressure of the overflow valve 2, because the first contact area is larger than the second contact area, the overflow valve core 22 will move rightwards relative to the valve sleeve 24 under the action of the oil pressure in the high pressure oil inlet chamber 231, so that the area of the high pressure oil inlet chamber 231 blocked by the valve sleeve 24 is gradually reduced, and the high pressure oil inlet chamber 231 is communicated with the low pressure oil outlet chamber 232, thereby realizing the pressure relief.

Further, the relief valve core 22 can abut against the displacement valve seat 262 and the power valve seat 252 at the same time. Specifically, one end of the power valve seat 252 is spherical, and one end of the power valve seat 252 opposite to the power elastic member 251 is slidably sleeved on the displacement valve seat 262. The displacement valve seat 262 is provided with a through hole, one end of the power valve seat 252, which faces away from the power elastic member 251, is slidably connected with the through hole, and preferably, the maximum outer diameter of the power valve seat 252 is larger than the inner diameter of the through hole. The structure of the power valve seat 252 is not limited to the above structure, and may be a stepped structure.

In the process of constant power adjustment of the variable power valve set, the valve sleeve 24 is moved to the right as an example. During the rightward movement of the valve sleeve 24, the valve sleeve 24 will further compress the displacement elastic member 261 through the displacement valve seat 262, and since the maximum outer diameter of the power valve seat 252 is larger than the inner diameter of the through hole on the displacement valve seat 262, after the displacement valve seat 262 moves rightward for a certain distance, the valve sleeve 24 will push the power valve seat 252 to move rightward while further compressing the displacement elastic member 261 through the displacement valve seat 262, so that the power elastic member 251 is further compressed, and the relief valve core 22 will also move rightward, thereby implementing the "double-fold line" type constant power control of the variable power control device.

Further, the valve body is provided with a power adjustment lever 27 that is movable or fixed in the axial direction, and is provided on a side of the power elastic member 251 facing away from the relief valve core 22, and one end of the power elastic member 251 abuts against the power adjustment lever 27. The pre-tightening force of the power elastic element 251 can be adjusted by adjusting the power adjusting rod 27, so as to adjust the opening pressure of the overflow valve 2.

Further, the variable power valve set further comprises a buffer spring 29, one end of which is connected to the inner wall of the valve body, and the other end of which is connected to the overflow valve core 22. Specifically, one end of the cushion spring 29 abuts against the inner wall of the first bonnet 212, and the other end is connected to the relief valve spool 22.

The embodiment also provides a hydraulic system which comprises the variable power control device.

It is obvious that the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Claims (10)

1. The utility model provides a change power valves, its characterized in that, includes the valve body, and locates in the valve body:

the overflow valve core (22) is arranged in the valve body in a sliding manner along the axial direction;

the variable power valve is characterized in that a variable power valve core (3) of the variable power valve is arranged at one end of the overflow valve core (22) in an axial sliding mode and abuts against the overflow valve core (22), and the inlet oil pressure of the variable power valve is determined according to the required power of an engine on the engineering vehicle;

and the power elastic piece (251) is arranged at the other end of the overflow valve core (22), one end of the power elastic piece (251) is fixed relative to the valve body, and the other end can be abutted against the overflow valve core (22) through a power valve seat (252).

2. A variable power valve manifold as claimed in claim 1, further comprising, disposed within the valve body:

the valve sleeve (24) is arranged in the valve body in an axial sliding mode and used for being connected with a swash plate (11) of the variable displacement pump (1), and the overflow valve core (22) is arranged in the valve sleeve (24) in a sliding mode;

the displacement elastic piece (261) and the power elastic piece (251) are arranged at the same end of the overflow valve core (22), one end of the displacement elastic piece (261) abuts against the inner wall of the valve body, the other end of the displacement elastic piece can abut against the valve sleeve (24) through a displacement valve seat (262), and the displacement valve seat (262) is in sliding connection with the power valve seat (252).

3. The variable power valve group according to claim 2, wherein the overflow spool (22) comprises a first portion (221), a second portion (222) and a third portion (223) which are axially arranged in sequence, the outer diameter of the second portion (222) is smaller than that of the first portion (221) and smaller than that of the third portion (223) so that a high pressure oil inlet chamber (231) is formed between the overflow spool (22) and the valve sleeve (24), and the contact area of the first portion (221) and the high pressure oil inlet chamber (231) is smaller than that of the third portion (223) and the high pressure oil inlet chamber (231);

the overflow valve core (22) can selectively enable the high-pressure oil inlet cavity (231) to be communicated with the low-pressure oil outlet cavity (232) on the valve body, or enable the high-pressure oil inlet cavity (231) to be completely disconnected with the low-pressure oil outlet cavity (232).

4. Power variable valve group according to claim 1, characterized in that the valve body is provided with a power adjusting rod (27) which can move or be fixed relative to the valve body in the axial direction, the power adjusting rod is arranged on the side of the power elastic member (251) opposite to the overflow valve core (22), and one end of the power elastic member (251) is abutted to the power adjusting rod (27).

5. The variable power valve group according to claim 1, characterized in that the valve body is provided with a power pressure regulating hole (2121), a buffer orifice (2122) and a valve core mounting hole (2123) which are sequentially communicated along the axial direction of the valve body, and the aperture of the buffer orifice (2122) is smaller than that of the power pressure regulating hole (2121) and smaller than that of the valve core mounting hole (2123);

the variable power valve core (3) is arranged in the valve core mounting hole (2123) in a sliding mode.

6. A variable power control device comprising a variable power valve pack according to any one of claims 1 to 5.

7. The variable power control device according to claim 6, further comprising a variable pump (1), a load sensitive assembly and a servo variable cylinder (4);

a rodless servo cavity (41) of the servo variable oil cylinder (4) can be selectively communicated with an oil outlet of the variable pump (1) or a hydraulic oil tank through the load sensitive assembly;

a piston rod of the servo variable oil cylinder (4) is connected with a swash plate (11) of the variable pump (1),

the variable power valve group further comprises a valve sleeve (24) and a displacement elastic piece (261), wherein the swash plate (11) is connected with the valve sleeve (24) and can push the valve sleeve (24) to move axially relative to the valve body, so that the valve sleeve (24) keeps balance under the combined action of the swash plate (11) and the displacement elastic piece (261).

8. The variable power control device of claim 7, wherein the load sensitive component comprises:

the load sensitive valve (51) comprises a first P port, a first T port, a first working oil port, a first pilot control oil port and a second pilot control oil port, the first P port is communicated with an oil outlet of the variable pump (1), the first T port is communicated with the hydraulic oil tank, and the first working oil port is communicated with the rodless servo cavity (41); the first working oil port can be selectively communicated with the first P port or the first T port; the first pilot control oil port is communicated with an oil outlet of the variable pump (1);

and the second pilot control oil port and a return spring of the load sensitive valve (51) are positioned on the same side, an oil outlet of the variable pump (1) is communicated with an oil inlet of the flow control valve (52), and an oil outlet of the flow control valve (52) is simultaneously communicated with the second pilot control oil port and the load.

9. The variable power control device according to claim 8, further comprising a pressure cut-off valve (6) including a second P port communicating with an oil outlet of the variable pump (1), a second T port communicating with the hydraulic oil tank, and a second working oil port communicating with the rodless servo chamber (41), the first working oil port communicating with the second P port; a pilot control oil port of the pressure cut-off valve (6) is communicated with an oil outlet of the variable pump (1);

the second working oil port can be selectively communicated with the second P port or the second T port.

10. A hydraulic system comprising a variable power control apparatus according to any one of claims 6 to 9.

Images