CN215486908U - Pilot cushion valve, pilot control loop and engineering machinery - Google Patents

Abstract

The utility model relates to a cushion valve and discloses a pilot cushion valve, a pilot control loop and engineering machinery, wherein the pilot cushion valve comprises a valve body, two one-way valves and a plunger positioned between the two one-way valves are arranged in the valve body along the axial direction; the check valve comprises a valve core and a throttling hole arranged on the valve core, the valve body comprises a first oil inlet, a first oil outlet, a second oil inlet and a second oil outlet, the valve core is arranged between the first oil inlet and the first oil outlet and between the second oil inlet and the second oil outlet respectively, and the plunger can push the valve core to enable the first oil inlet and the first oil outlet and the second oil inlet and the second oil outlet to be communicated respectively. The pilot cushion valve eliminates leakage between the valve core and the valve body, and can effectively reduce the inertia impact effect of the actuating mechanism.

Description

Pilot cushion valve, pilot control loop and engineering machinery

Technical Field

The utility model relates to a cushion valve, in particular to a pilot cushion valve. In addition, still relate to a pilot control circuit and engineering machine tool.

Background

In order to slow down the time of the valve core of the main control valve returning to the neutral position, a cushion valve is generally arranged between the pilot control valve and the main control valve so as to reduce the effect of inertia impact on an actuating structure (such as a hydraulic oil cylinder or a hydraulic motor).

As shown in fig. 1, the cushion valve is installed between the pilot control valve 6 and the main control valve 7, a left oil inlet a of the cushion valve is connected with an oil inlet of the first one-way throttle valve and a left pilot cavity of the reversing valve 8, a right oil inlet C of the cushion valve is connected with an oil inlet of the second one-way throttle valve and a right pilot cavity of the reversing valve 8, two working oil ports of the reversing valve 8 are connected with an oil outlet of the first one-way throttle valve and an oil outlet of the second one-way throttle valve in a one-to-one correspondence manner, an oil outlet of the first one-way throttle valve is connected with a left oil outlet B of the cushion valve, an oil outlet of the second one-way throttle valve is connected with a right oil outlet D of the cushion valve, and an oil return port T of the reversing valve 8 is connected with an oil return port T of the cushion valve.

The operation principle of the hydraulic control device will be further described below, and the operation principle of the hydraulic control device when the pilot control valve 6 is operated to make the pilot oil enter the left oil inlet a of the cushion valve from the left oil port a is the same as the operation principle of the hydraulic control device when the pilot control valve 6 is operated to make the pilot oil enter the right oil inlet C of the cushion valve from the right oil port b.

When the pilot control valve 6 is operated to enable pilot oil to enter the left oil inlet A of the buffer valve from the left oil port a, a part of the pilot oil enters the right pilot cavity Xa of the main control valve 7 through the check valve; meanwhile, the other part of pilot oil enters the left pilot cavity of the reversing valve 8 and reaches the left position function, so that the pilot oil in the left pilot cavity Xb of the main control valve 7 flows back to the oil tank through the right oil outlet D and the oil return port T of the buffer valve, the main control valve core is pushed to reverse left, and the pressure oil of the working pump enters the rod cavity of the oil cylinder.

When the pilot control valve 6 stops being operated, the left oil inlet A and the left oil outlet B of the buffer valve have no pressure output, and the reversing valve 8 moves leftwards under the action of the spring and is in a middle cut-off state; the main control valve core moves rightwards under the action of the spring to push pilot oil in the pilot cavity Xa on the right side of the main control valve core to flow to the left oil outlet B of the buffer valve, and theoretically, the pilot oil flows back to the oil tank through the throttling hole.

SUMMERY OF THE UTILITY MODEL

The present invention has been made in an effort to solve the above-described problems, and an object of the present invention is to provide a pilot cushion valve that eliminates leakage between a valve element and a valve body and effectively reduces the effect of inertial shock of an actuator.

The object of the second aspect of the present invention is to provide a pilot control circuit that can effectively reduce the effect of inertial shock of an actuator.

A third aspect of the present invention is to provide a construction machine that can effectively reduce the effect of inertial shock of an actuator.

In order to solve the technical problem, the utility model provides a pilot cushion valve, which comprises a valve body, wherein two one-way valves and a plunger positioned between the two one-way valves are arranged in the valve body along the axial direction; the check valve comprises a valve core and a throttling hole arranged on the valve core, the valve body comprises a first oil inlet, a first oil outlet, a second oil inlet and a second oil outlet, the valve core is arranged between the first oil inlet and the first oil outlet and between the second oil inlet and the second oil outlet respectively, and the plunger can push the valve core to enable the first oil inlet to be communicated with the first oil outlet or the second oil inlet to be communicated with the second oil outlet.

Optionally, the check valve further includes a valve housing fixedly disposed in the valve body, the valve core is axially movably disposed in the valve housing, and a main valve port is formed between the valve core and the valve housing.

Optionally, a first through hole is provided in an end wall of the valve housing close to the plunger, and the valve core includes a sliding section and a sealing section, and the sealing section can seal the first through hole to block the main valve port.

Specifically, the end part, close to the plunger, of the sealing section is of a truncated cone structure.

Specifically, the plunger comprises a stage and pushing sections positioned at two ends of the stage, the cross-sectional area of each pushing section is smaller than that of the stage, and the cross-sectional area of each pushing section is smaller than that of the first through hole.

Optionally, the valve further comprises a reset element, one end of the reset element is blocked against the end part of the valve body, and the other end of the reset element abuts against the valve core.

Specifically, a second through hole is formed in the valve core, a groove is formed in the end portion, close to the plunger, of the valve core, and the second through hole is communicated with the groove through the throttling hole.

Optionally, the number of the valve bodies is two, the first oil outlet of one valve body is connected with the first oil inlet of the other valve body, and the second oil outlet of one valve body is connected with the second oil inlet of the other valve body.

The utility model also provides a pilot control loop, which comprises a pilot control valve, a main control valve and the pilot cushion valve in any one of the technical schemes, wherein the pilot control valve is connected with the main control valve through the pilot cushion valve.

The utility model also provides engineering machinery comprising the pilot control loop in the technical scheme.

Through the technical scheme, the utility model has the following beneficial effects:

the utility model cancels the reversing valve structure in the buffer valve in the prior art, uses the plunger to control the opening of the one-way valve at one side, and eliminates the leakage between the valve core and the valve body. In the pilot control loop, when the pilot control valve is operated to enable pilot oil to enter the buffer valve, the pilot oil can directly flow to the pilot cavity at one end of the main control valve through the one-way valve at one end, and meanwhile, the plunger pushes the one-way valve at the other end to enable the pilot oil in the pilot cavity at the other end of the main control valve to flow back to the oil tank through the corresponding one-way valve, so that the hydraulic oil cylinder can be normally controlled; when the pilot control valve is stopped, the plunger returns to the middle position, the first oil inlet is communicated with the first oil outlet through the throttling hole in the corresponding valve core, and the second oil inlet is communicated with the second oil outlet through the throttling hole in the corresponding valve core, so that the main control valve core slowly returns to the middle position, the hydraulic oil cylinder is slowly stopped, and the effect of reducing the inertia impact of the actuating mechanism is achieved.

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

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the principles of the utility model and not to limit the utility model. In the drawings:

FIG. 1 is a hydraulic schematic of a prior art pilot control circuit;

FIG. 2 is a prior art measured pilot pressure curve;

FIG. 3 is one of the schematic structural views of a pilot trim valve according to a first embodiment of the present invention;

FIG. 4 is one of the enlarged partial views of section I of FIG. 3 with the pilot trim valve in an initial condition;

FIG. 5 is a second enlarged partial view of section I of FIG. 3, with the pilot trim valve in a deactivated condition;

FIG. 6 is a second schematic structural view of a pilot trim valve according to an embodiment of the present invention, wherein the pilot trim valve is in a normal operating state;

FIG. 7 is an enlarged view of a portion II of FIG. 6;

FIG. 8 is an enlarged view of a portion III of FIG. 6;

fig. 9 is a hydraulic schematic diagram of a pilot control circuit according to a second embodiment of the present invention;

FIG. 10 is a hydraulic schematic of a pilot trim valve according to a third embodiment of the present invention;

fig. 11 is a measured pilot pressure curve according to an embodiment of the present invention.

Description of the reference numerals

1 first oil inlet of valve body A1

A2 first oil outlet B1 second oil inlet

B2 second oil outlet 2 plunger

31 valve core 32 orifice

33 valve housing 34 first through hole

35 second through hole 36 groove

4 end closure of the reduction element 5

6 left side oil port of pilot control valve a

b right side oil port 7 main control valve

Xa right pilot chamber Xb left pilot chamber

8 left side oil inlet of reversing valve A cushion valve

Left side oil outlet of B cushion valve and right side oil inlet of C cushion valve

D-buffer valve oil return port of right side oil outlet T-buffer valve

9 pilot cushion valve

Detailed Description

The following detailed description of embodiments of the utility model 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.

In the description of the present invention, it should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "disposed" or "connected" are to be construed broadly, e.g., the term "connected" may be a fixed connection, a detachable 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.

Furthermore, 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 the features described.

In the present invention, unless otherwise specified, the terms of orientation such as "inner and outer" are used as being defined with respect to the inner and outer of the respective components, and "left and right" are defined with respect to the plane of the drawing of the respective drawings, and "axial" is defined with respect to the direction of arrangement of the check valve of the pilot cushion valve provided by the present invention, specifically, in the drawings provided by the present invention, "axial" is the left-right direction of the plane of the drawing, and "radial" is the direction perpendicular to the "axial" direction. It is to be understood that these terms are merely illustrative of the present invention and are not intended to limit the utility model.

As shown in fig. 3 to 8, the utility model provides a pilot cushion valve, which comprises a valve body 1, two check valves and a plunger 2, wherein the two check valves and the plunger 2 are arranged in the valve body 1 along the axial direction; the check valve comprises a valve core 31 and a throttle hole 32 arranged on the valve core 31, the valve body comprises a first oil inlet A1, a first oil outlet A2, a second oil inlet B1 and a second oil outlet B2, the valve core 31 is respectively arranged between the first oil inlet A1 and the first oil outlet A2 and between the second oil inlet B1 and the second oil outlet B2, and the plunger 2 can push the valve core 31 to enable the first oil inlet A1 and the first oil outlet A2 or the second oil inlet B1 and the second oil outlet B2 to be communicated.

In the pilot cushion valve, a plunger 2 is arranged between two one-way valves, an oil inlet of the pilot cushion valve is divided into a first oil inlet A1 and a second oil inlet B1, an oil outlet of the pilot cushion valve is divided into a first oil outlet A2 and a second oil outlet B2, a valve core 31 is arranged between a first oil inlet A1 and a first oil outlet A2, a valve core 31 is arranged between a second oil inlet B1 and a second oil outlet B2, and the plunger 2 can push the valve core 31 of the one-way valve to move axially so as to open a channel between the first oil inlet A1 and a first oil outlet A2 or open a channel between the second oil inlet B1 and a second oil outlet B2.

Specifically, referring to fig. 9, since the left oil port a of the pilot control valve 6 delivers pilot oil to the main control valve 7 through the pilot cushion valve 9 and the right oil port b of the pilot control valve 6 delivers pilot oil to the main control valve 7 through the pilot cushion valve 9, the working principle is the same, and therefore, the working process of delivering the pilot oil to the main control valve 7 through the left oil port a of the pilot control valve 6 and the pilot cushion valve 9 will be described; referring to fig. 6 to 8, when the pilot control valve 6 is operated to make the pilot oil enter the pilot cushion valve 9, the pilot oil flowing in from the first oil inlet a1 is divided into two parts, one part pushes the corresponding valve spool 31 to move leftward, and opens the channel between the first oil inlet a1 and the first oil outlet a2, so that the pilot oil flows to the right pilot Xa cavity of the main control valve 7 through the first oil outlet a2, and pushes the main control valve spool to move leftward, and reaches the left position function, so that the pressure oil output by the hydraulic pump enters the rod cavity of the hydraulic cylinder; meanwhile, the other part of pilot oil pushes the plunger 2 to move rightwards, the plunger 2 pushes the right valve core 31 to move, a channel between a second oil inlet B1 and a second oil outlet B2 is opened, the main control valve core moves leftwards and pushes the oil in the left pilot cavity Xb of the main control valve 7 to flow to the second oil outlet B2, and therefore the oil flows back to the oil tank through the second oil inlet B1 and the right oil port B of the pilot control valve 6 in sequence, and the retraction action of the hydraulic oil cylinder is achieved; when the pilot control valve 6 stops operating, because the first oil inlet a1 has no pilot oil, the main control valve spool will move rightwards under the action of the spring, so that the oil in the right pilot cavity Xa flows to the first oil outlet a2, at this time, referring to fig. 3, the valve spool 31 has returned to the initial position, the first oil inlet a1 and the first oil outlet a2 are connected through the corresponding throttle hole 32 on the valve spool 31, so that the oil can only flow to the first oil inlet a1 through the throttle hole 32, the pressure is quickly built up and the main control valve spool slowly moves rightwards, thereby the hydraulic oil cylinder is slowly stopped, and the effect of reducing the inertia impact of the actuator is achieved. Similarly, when the pilot control valve 6 is operated to enable the pilot oil to enter the pilot cushion valve 9 through the second oil inlet B1, the extending action of the hydraulic oil cylinder can be realized and the effect of reducing the inertia impact of the actuating mechanism can be achieved. Compared with the prior art, the utility model cancels the reversing valve 8 in the buffer valve in the prior scheme, eliminates the leakage between the reversing valve 8 and the valve body 1, has good buffering and throttling effects, avoids the impact on the whole machine caused by inertia, and can ensure the stable and reliable work of the actuating mechanism.

The two check valves of the pilot cushion valve according to the present invention have the same structure, and for convenience of description, the following description will mainly use the left check valve as an example.

Usually, the check valve further includes a valve housing 33, the valve housing 33 is fixedly disposed in the valve body 1, a through hole is disposed on a side wall of the valve housing 33 and can communicate with the oil outlet on the valve body 1, for example, referring to fig. 3, a first oil outlet a2 communicates with the through hole on the left side valve housing 33, and a second oil outlet B2 communicates with the through hole on the right side valve housing 33; the spool 31 is disposed within a corresponding valve sleeve 33 and is movable in the axial direction, with a main valve port formed between the spool 31 and the valve sleeve 33.

Specifically, referring to fig. 4, fig. 4 shows a structural form of the left check valve, a first through hole 34 is arranged on an end wall of a valve sleeve 33, the first through hole 34 is close to a plunger 2, the first through hole 34 is an oil inlet of the check valve and is communicated with a corresponding first oil inlet a1 on a valve body 1, and a through hole on a side wall of the valve sleeve 33 is an oil outlet of the check valve and is communicated with a corresponding first oil outlet a2 on the valve body 1; correspondingly, the valve core 31 can be divided into two parts, namely a sliding section and a sealing section, the outer peripheral surface of the sliding section is attached to the inner side wall of the valve sleeve 33 and can move in the valve sleeve 33, the sliding section can drive the sealing section to move towards the first through hole 34 of the valve sleeve 33, so that the sealing section extends into the first through hole 34, fig. 4 provides a sealing matching structural form between the valve core 31 and the first through hole 34, wherein the end part of the sealing section is set to be in a cone frustum structure, so that the end part of the sealing section can realize conical surface sealing with the first through hole 34; of course, the valve core 31 may have other structures capable of achieving sealing, for example, the sealing section of the valve core 31 may have a cylindrical structure, the outer diameter of the cylindrical structure is equal to the inner diameter of the first through hole 34, and the sealing section of the valve core 31 is inserted into the first through hole 34 to achieve sealing engagement therebetween, or the outer diameter of the cylindrical structure is larger than the inner diameter of the first through hole 34 and equal to the inner diameter thereof, and the end of the first through hole 34 close to the valve core 31 forms a stepped structure, so that the sealing section of the valve core 31 directly abuts against the end surface of the first through hole 34 to achieve sealing engagement therebetween.

In order to realize that the valve core 31 can be reset after moving, a reset element 4 can be arranged between the end plug 5 of the valve body 1 and the valve core 31, one end of the reset element 4 abuts against the end plug 5, and the other end of the reset element abuts against the valve core 31; the return element 4 is preferably a return spring. In specific work, one part of pilot oil pushes the valve core 31 to overcome the elastic force of the return spring and open the valve port of the one-way valve on one side, and the other part of pilot oil pushes the plunger 2, so that the plunger 2 pushes the valve core 31 to overcome the elastic force of the return spring and open the valve port of the one-way valve on the other side, and the pilot control valve 6 can provide pilot oil for the main control valve 7 through the pilot buffer valve 9; when the pilot control valve 6 stops operating, the valve core 31 can be restored to the initial position under the action of the return spring, so that the oil inlet and the oil outlet of the pilot cushion valve 9 are communicated through the throttling hole, and the oil return process can be slowly carried out.

In the embodiment of the present invention, referring to fig. 3, the plunger 2 is divided into a stage and a pushing stage, the outer peripheral surface of the stage is attached to the inner wall of the valve body 1 and can move in the valve body 1 along the axial direction, the cross-sectional area of the pushing stage is smaller than that of the stage, and oil can act on the outer peripheral surface of the pushing stage to push the plunger 2 to move; the cross-sectional area of the pushing section is smaller than that of the first through hole 34, and when the plunger 2 is in the neutral position, the pushing section of the plunger 2 can stretch into the first through hole 34 with a gap.

In the embodiment of the present invention, referring to fig. 4, the valve body 31 is provided with the second through hole 35, the end portion of the valve body 31 is provided with the groove 36, the groove 36 is close to the plunger 2, and the second through hole 35 communicates with the groove 36 through the orifice 32. The second through hole 35 communicates with the through hole of the valve sleeve 33 when the spool 31 is in the initial position.

In general, the diameter of the orifice 32 may need to be adapted according to the size of the closed volume at both ends of the main control spool, for example, in a specific embodiment, the diameter of the orifice 32 may be within the range of

In the meantime. If the aperture of the throttle hole 32 is too small, the throttle hole 32 may be blocked by system impurities in the practical application process, so that the return oil at two ends of the main control valve core cannot return smoothly, and a system fault is caused. For this reason, referring to fig. 10, 2 large orifices 32 can be selected to be used in series, so that the first oil outlet a2 of one valve body 1 is connected with the first oil inlet a1 of the other valve body 1, and the second oil outlet B2 of the one valve body 1 is connected with the second oil inlet B1 of the other valve body 1, thereby ensuring the smoothness of oil return at both ends of the main control valve core.

Referring to fig. 9, the pilot control circuit provided by the present invention includes a pilot control valve, a main control valve, and a pilot cushion valve 9, wherein the pilot control valve 6 is connected to the main control valve 7 through the pilot cushion valve 9; the pilot cushion valve 9 is the pilot cushion valve described in the above embodiment.

Specifically, a left oil port a of the pilot control valve 6 is connected with a first oil inlet a1 of the pilot cushion valve 9, a right oil port B of the pilot control valve 6 is connected with a second oil inlet B1 of the pilot cushion valve 9, a first oil outlet a2 of the pilot cushion valve 9 is connected with a right pilot cavity Xa of the main control valve 7, and a second oil outlet B2 of the pilot cushion valve 9 is connected with a left pilot cavity Xb of the main control valve 7.

When the pilot oil is output from the pilot control valve 6 to the pilot cushion valve 9, a part of the pilot oil pushes the spool 31 of the check valve on one side to move, so as to form an oil supply path for supplying the pilot oil to the main control valve 7, and the other part of the pilot oil pushes the plunger 2, so that the plunger 2 pushes the spool 31 of the check valve on the other side to move, so as to form an oil return path for the main control valve 7, so that the main control valve 7 can normally control the action of the actuator. When the pilot control valve 6 stops operating, the valve core 31 returns to the initial position under the action of the return spring, so that the main control valve 7 returns oil through the throttle hole 32, pressure is quickly built up under the damping action of the throttle hole 32, the main control valve core moves slowly, the time for returning the main control valve core to the middle position is obviously slowed down, and the action of inertial impact of an actuating mechanism is effectively reduced.

Fig. 2 is a measured pilot pressure curve of the cushion valve in fig. 1, and shows a trajectory curve of a change in the pilot pressure with time. Pressure detection points are respectively connected to the positions of a left oil inlet A, a left oil outlet B, a right oil inlet C and a right oil outlet D of the buffer valve, the unit is bar (bar), the abscissa represents the time of pressure acquisition, the unit is second, and the acquisition frequency is 50 Hz.

And when the abscissa is within the interval from 15.4 seconds to 17.3 seconds, the pilot control valve 6 is operated, and the left oil port a of the pilot control valve 6 outputs pilot control pressure corresponding to a pressure curve of the left oil inlet A and the left oil outlet B. In the interval of 17.3 seconds to 19.2 seconds, at the moment, the pilot control valve 6 stops operating, and the buffer valve is activated, corresponding to the pressure curve of the left oil inlet A and the left oil outlet B. In the interval from 19.2 seconds to 21 seconds, the pilot control valve is operated, and the oil port of the pilot control valve b outputs pilot control pressure corresponding to the pressure curve of the right oil inlet C and the right oil outlet D. In the interval of 21 seconds to 22 seconds, at the moment, the pilot control valve stops operating, and the buffer valve is activated, corresponding to the pressure curves of the right oil inlet C and the right oil outlet D.

As can be seen from fig. 2, when the pilot control valve 6 stops operating, the pressure change curve of the left oil outlet B and the pressure change curve of the left oil inlet a tend to coincide in the interval of 17.3 seconds to 19.2 seconds. In the interval of 21 seconds to 22 seconds, the pressure change curve of the right oil outlet D and the pressure change curve of the right oil inlet C tend to coincide. Therefore, the buffer valve in the prior art does not have the buffering and throttling effect, and is matched with the phenomenon that the front and back shaking of the whole excavator is obvious when the movable arm and the bucket rod of the excavator equipped with the buffer valve in the prior art suddenly stop in actual operation.

Fig. 11 is a measured pilot pressure curve of the pilot cushion valve according to the present invention, and shows a trajectory curve of a change in the pilot pressure with time. Pressure detection points are respectively connected to the positions of a first oil inlet A1, a first oil outlet A2, a second oil inlet B1 and a second oil outlet B2 of the pilot cushion valve, and the unit is bar (bar). The abscissa represents the time of pressure acquisition in seconds, with an acquisition frequency of 50 Hz.

In the interval of the abscissa from 1.1 second to 3.9 seconds, the pilot control valve 6 is operated at this time, and the left oil port a of the pilot control valve 6 outputs pilot control pressure corresponding to the pressure curves of the first oil inlet a1 and the first oil outlet a 2. In the interval of 3.9 seconds to 6.9 seconds, when the pilot control valve 6 stops operating, the pilot cushion valve is activated, corresponding to the pressure curve of the first oil inlet a1 and the first oil outlet a 2. In the interval of 6.9 seconds to 10 seconds, when the pilot control valve 6 is operated, the right side oil port B of the pilot control valve 6 outputs the pilot control pressure, which corresponds to the pressure curve of the second oil inlet B1 and the second oil outlet B2. In the interval of 10 seconds to 12 seconds, when the pilot control valve 6 stops operating, the pilot cushion valve is activated, corresponding to the pressure curves of the second oil inlet B1 and the second oil outlet B2.

As can be seen from fig. 11, when the pilot control valve 6 stops operating, the tendency of the return oil pressure of the first oil outlet a2 to decrease in the interval of 3.9 seconds to 6.9 seconds is significantly delayed from the return oil pressure of the first oil inlet a 1. In the interval of 10 seconds to 12 seconds, the trend of the return oil pressure of the second oil outlet B2 is reduced and lags behind the return oil pressure of the second oil inlet B1 obviously.

Therefore, when the pilot control valve 6 stops operating, the pilot buffer valve obviously slows down the time for reducing the return oil pressure of the pilot cavities at the two ends of the main control valve core, effectively delays the time for returning the main control valve core to the middle position, and reduces the impact on the whole hydraulic oil cylinder caused by the inertia of a working device when the hydraulic oil cylinder stops suddenly.

Therefore, the utility model can eliminate the leakage between the valve core and the valve body 1 of the three-position three-way reversing valve in the buffer valve in the prior art, play a role in buffering and ensure the stable and reliable work of the whole machine.

The pilot cushion valve provided by the utility model can be applied to engineering machinery such as an excavator and the like, so that the engineering machinery has better working stability.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the utility model. The utility model is not described in detail in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims (10)

1. A pilot cushion valve comprises a valve body (1), and is characterized in that two one-way valves and a plunger (2) positioned between the two one-way valves are arranged in the valve body (1) along the axial direction; the check valve comprises a valve core (31) and a throttling hole (32) arranged on the valve core (31), the valve body comprises a first oil inlet (A1), a first oil outlet (A2), a second oil inlet (B1) and a second oil outlet (B2), the valve core (31) is arranged between the first oil inlet (A1) and the first oil outlet (A2) and between the second oil inlet (B1) and the second oil outlet (B2), and the plunger (2) can push the valve core (31) to enable the first oil inlet (A1) and the first oil outlet (A2) or enable the second oil inlet (B1) and the second oil outlet (B2) to be communicated.

2. The pilot trim valve according to claim 1, characterized in that the check valve further comprises a valve sleeve (33) fixedly arranged in the valve body (1), the spool (31) is axially movably arranged in the valve sleeve (33), and a main valve port is formed between the spool (31) and the valve sleeve (33).

3. The pilot trim valve according to claim 2, characterized in that the valve sleeve (33) is provided with a first through hole (34) in an end wall close to the plunger (2), and the valve spool (31) comprises a sliding section and a sealing section, and the sealing section can seal the first through hole (34) to block the main valve port.

4. The pilot cushion valve according to claim 3, wherein the end of the sealing section close to the plunger (2) is of a truncated cone configuration.

5. The pilot trim valve according to claim 3, characterized in that the plunger (2) comprises a land section and a push section at both ends of the land section, the cross-sectional area of the push section being smaller than the cross-sectional area of the land section and the cross-sectional area of the push section being smaller than the cross-sectional area of the first through hole (34).

6. The pilot trim valve according to any of claims 1 to 5, characterized by a return element (4), which return element (4) has one end abutting against the end plug (5) of the valve body (1) and its other end abutting against the valve spool (31).

7. The pilot trim valve according to any one of claims 1 to 5, characterized in that a second through hole (35) is provided in the spool (31), and a groove (36) is provided in an end of the spool (31) near the plunger (2), the second through hole (35) communicating with the groove (36) through the orifice (32).

8. The pilot trim valve according to any one of claims 1 to 5, characterized in that the number of the valve bodies (1) is two, the first oil outlet (A2) of one valve body (1) is connected with the first oil inlet (A1) of the other valve body (1), and the second oil outlet (B2) of one valve body (1) is connected with the second oil inlet (B1) of the other valve body (1).

9. Pilot control circuit, characterized in that it comprises a pilot control valve, a main control valve and a pilot trim valve (9) according to any of claims 1 to 8, the pilot control valve (6) being connected with the main control valve (7) through the pilot trim valve (9).

10. A working machine, characterized by comprising a pilot control circuit according to claim 9.

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