CN220792154U - Variable mechanism, traveling motor and traveling equipment - Google Patents

Abstract

The utility model relates to the technical field of hydraulic motor control, in particular to a variable mechanism, a traveling motor and traveling equipment. The variable mechanism comprises a valve body, a valve core, a pilot part and a feedback rod, wherein the valve body is provided with a high-pressure oil duct, an oil drain oil duct, a first feedback oil duct and a working oil duct, a containing cavity is further formed in the valve body, an oil storage cavity and a second feedback oil duct are formed in the valve core, the second feedback oil duct is communicated with the oil storage cavity, and the feedback rod is connected with the inner wall of the containing cavity and is contained in the oil storage cavity. When the high-pressure oil duct is in the first working state, the high-pressure oil duct is communicated with the working oil duct; when the first working state is in the second working state, the first feedback oil duct is communicated with the second feedback oil duct, and the oil drain duct is communicated with the working oil duct. According to the variable mechanism, the first feedback oil duct and the second feedback oil duct are utilized, the feedback rod and the oil storage cavity are combined, and the valve core can be controlled to move along the axial direction through feedback hydraulic oil.

Description

Variable mechanism, traveling motor and traveling equipment

Technical Field

The utility model relates to the technical field of hydraulic motor control, in particular to a variable mechanism, a traveling motor and traveling equipment.

Background

Hydraulic variable mechanisms are widely used in many fields, such as engineering machinery, aviation, marine and industrial automation. They are mainly used to precisely control the movement, speed and position of the machine. To meet the needs of various applications, the design and manufacture of hydraulic variable mechanisms must meet a high degree of accuracy and reliability.

In the conventional hydraulic variable mechanism, the function of the self-feedback variable is mainly realized by means of the area difference. Such designs typically involve a valve core and a valve bore having a stepped shape (the valve bore being provided on an inner wall of the valve body). Both parts require a sealing function to ensure that hydraulic oil does not leak from unwanted places. However, this design places high demands on the coaxiality between the steps. If machining is inaccurate during manufacturing, this differential axiality is difficult to compensate for by subsequent adjustment. This may result in an unnecessary connection between the self-feedback oil passage and the pilot oil passage, resulting in excessive pressure in the pilot oil passage. Such excessive pressures can interfere with proper variable function, leading to unstable operation of the variable mechanism and possibly even mechanical failure.

Disclosure of Invention

The utility model aims to at least solve the problem that the valve core or the valve hole has higher processing requirements. The aim is achieved by the following technical scheme:

a first aspect of the present utility model proposes a variable mechanism comprising:

the high-pressure oil duct, the oil drain duct, the first feedback oil duct and the working oil duct are arranged on the valve body, and a containing cavity is formed in the valve body;

the valve core is arranged in the accommodating cavity in a sliding manner, an oil storage cavity is formed in the valve core, a second feedback oil duct communicated with the oil storage cavity is formed in the valve core, and a first oil guide channel and a second oil guide channel are also formed in the valve core;

the feedback rod is inserted into the oil storage cavity at least partially and is connected with the inner wall of the oil storage cavity in a sealing way;

the pilot part is arranged in the valve body and used for driving the valve core to move towards the direction approaching the feedback rod;

when the valve is in a first working state, the pilot part controls the valve core to move along the direction approaching to the feedback rod, so that the high-pressure oil channel is communicated with the working oil channel through the first oil guide channel;

when the valve is in the second working state, the first feedback oil duct is communicated with the second feedback oil duct, and the valve core is driven to move towards the direction away from the feedback rod, so that the oil drain duct is communicated with the working oil duct through the second oil guide channel.

According to the variable mechanism, the pilot part applies a force to the valve core to enable the valve core to move towards the direction close to the feedback rod, the high-pressure oil channel is communicated with the working oil channel at the moment, when feedback is needed, hydraulic oil flows to the oil storage cavity through the first feedback oil channel and the second feedback oil channel, the pressure in the oil storage cavity is increased, and when the pressure in the oil storage cavity is larger than the force applied to the valve core by the pilot part, the valve core moves towards the direction far away from the feedback rod, and the oil drain channel is communicated with the working oil channel at the moment. Through utilizing first feedback oil duct and second feedback oil duct, combine feedback pole and oil storage chamber, can control the axial removal of case along its axial through the hydraulic oil of feedback, realized a feedback mechanism, consequently, need not set up traditional ladder-shaped's structure on case or the valve opening and also can satisfy the feedback demand, simplified the processing degree of difficulty of case or valve opening, the cost is reduced.

In addition, the variable mechanism according to the utility model can also have the following additional technical characteristics:

in some embodiments of the present utility model, the pilot portion includes a pilot oil passage, and an oil passing gap is provided between one end of the valve element and an inner wall surface of the valve body, and the oil passing gap is in communication with the pilot oil passage.

In some embodiments of the utility model, the first oil guide passage includes a first oil passage groove provided in a circumferential surface of the spool;

and/or the second oil guide channel comprises a second oil vent groove arranged on the circumferential surface of the valve core.

In some embodiments of the utility model, the first oil passing groove and the second oil passing groove are both in the shape of annular grooves.

In some embodiments of the present utility model, the variable mechanism further includes a limiting ring, the limiting ring is detachably disposed in the accommodating cavity, and the feedback rod is connected with an inner wall surface of the accommodating cavity through the limiting ring.

In some embodiments of the present utility model, the limiting ring is provided with a plurality of through holes, and the oil drain passage is communicated with the working oil passage through the through holes.

In some embodiments of the present utility model, the variable mechanism further includes an elastic portion, two ends of the elastic portion are respectively abutted against the valve core and the valve body, and when the valve core moves toward a direction approaching the feedback rod, the elastic portion is in a compressed state or an extended state.

In some embodiments of the present utility model, an annular sealing band is disposed on the circumferential side wall of the valve core, which is close to both sides of the second feedback oil passage, along the axial direction of the valve core.

A second aspect of the present utility model proposes a travel motor comprising:

a housing;

the swash plate is arranged in the shell;

the piston is connected with the swash plate;

according to the variable mechanism, the working oil duct of the variable mechanism is connected with the piston, and hydraulic oil of the working oil duct pushes the piston to jack up the swash plate so as to control the angle of the swash plate.

A third aspect of the utility model proposes a walking device comprising a walking motor as described above.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the utility model. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

FIG. 1 schematically illustrates a schematic structural view of a variable mechanism according to an embodiment of the present utility model;

FIG. 2 is an enlarged schematic view of the structure shown at A in FIG. 1;

fig. 3 is a schematic diagram of the variable mechanism of the present embodiment in a first operating state;

fig. 4 is a schematic diagram of the variable mechanism according to the present embodiment in the second operating state.

The reference numerals are as follows:

100. a variable mechanism;

10. a valve body; 11. a first feedback oil passage; 12. a high-pressure oil passage; 13. a working oil passage; 131. a first working oil passage; 132. a second working oil passage; 14. an oil drain passage; 15. a rear end cover; 16. a receiving chamber;

20. a valve core; 201. a first oil guide passage; 202. the second oil guide channel; 21. an oil storage chamber; 22. a sealing tape; 23. a second feedback oil passage;

30. a feedback lever; 40. a pilot section; 50. an elastic part; 60. plugging; 70. and a limiting ring.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "includes," "including," and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless an order of performance is explicitly stated. It should also be appreciated that additional or alternative steps may be used.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

For ease of description, spatially relative terms, such as "inner," "outer," "lower," "below," "upper," "above," and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the example term "below … …" may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative relationship descriptors used herein interpreted accordingly.

As shown in fig. 1 to 4, according to an embodiment of the present utility model, there is provided a variable mechanism 100, the variable mechanism 100 includes a valve body 10, a valve core 20, a pilot portion 40 and a feedback rod 30, wherein the valve body 10 is provided with a high-pressure oil passage 12, a drain oil passage 14, a first feedback oil passage 11 and a working oil passage 13, the working oil passage 13 is used for controlling an angle of a swash plate of a traveling motor, a receiving cavity 16 is further provided in the valve body 10, the valve core 20 is slidably disposed in the receiving cavity 16, an oil storage cavity 21 is provided in the valve core 20 along an axial direction of the valve core 20, a second feedback oil passage 23 is provided in the valve core 20 along a radial direction of the valve core 20, one end of the second feedback oil passage 23 and the oil storage cavity 21 is communicated (as shown in fig. 1, the second feedback oil passage 23 communicates with a top end of the oil storage cavity 21 in the embodiment), the pilot portion 40 is disposed in the interior of the valve body 10 and is used for driving the valve core 20 to move in a direction close to the feedback rod 30 (as shown in fig. 1, a direction close to the feedback rod 30 is a direction vertical downward along an axis of the feedback rod 30), the inner wall 30 is connected to the receiving cavity 16 and at least one end 21 of the second feedback rod 21 passes through the second feedback oil passage 23 and is connected to the other end 21 and passes through the other end 21 of the oil storage cavity 21 and is communicated with the other end 21. When in the first working state, the pilot portion 40 controls the valve core 20 to move in a direction approaching the feedback rod 30, and the high-pressure oil passage 12 is communicated with the working oil passage 13 for increasing the angle of the swash plate; when in the second working state, the first feedback oil passage 11 is communicated with the second feedback oil passage 23, the hydraulic oil of the first feedback oil passage 11 flows to the oil reservoir 21, so that the spool 20 moves in a direction away from the feedback rod 30 (as shown in fig. 1, the direction away from the feedback rod 30 in this embodiment is a direction vertically upward along the axis of the spool 20), and the oil drain passage 14 is communicated with the working oil passage 13 for reducing the angle of the swash plate.

According to the variable displacement mechanism 100 of the present utility model, the pilot portion 40 applies a force to the valve element 20 to move the valve element 20 in a direction approaching the feedback rod 30, and at this time, the high-pressure oil passage 12 and the working oil passage 13 are communicated, when feedback is required, the hydraulic oil flows into the oil reservoir chamber 21 through the first feedback oil passage 11 via the second feedback oil passage 23, the pressure in the oil reservoir chamber 21 increases, and when the pressure in the oil reservoir chamber 21 is greater than the force applied to the valve element 20 by the pilot portion 40, the valve element 20 moves in a direction approaching the feedback rod 30, and the drain oil passage 14 and the working oil passage 13 are communicated. Through utilizing first feedback oil duct 11 and second feedback oil duct 23, combine feedback rod 30 and oil storage chamber 21, can control the removal of case 20 along its axial through the hydraulic oil of feedback, realized an adaptive feedback mechanism, consequently, need not set up traditional ladder shape's design on case 20 or the valve opening and also can satisfy the feedback demand, the processing degree of difficulty of case 20 or valve opening has been simplified, make case 20 or valve opening can use same sword to honing, can be better guarantee axiality and then guarantee that the product can stabilize the variable, reduce a honing cutter simultaneously also can reduce cost.

It can be understood that the variable displacement mechanism 100 further includes an elastic portion 50, and when the valve element 20 moves toward the feedback rod 30, the elastic portion 50 is in a compressed state or a stretched state, and both ends of the elastic portion 50 are respectively abutted against the valve element 20 and the valve body 10.

Specifically, as shown in fig. 1, the elastic portion 50 is a spring, at this time, a chamber is provided near the top end of the valve body 10 near the valve core 20, the chamber is in an annular groove shape, the chamber accommodates a spring, the spring is sleeved on the circumferential side wall of the valve core 20, the top end of the spring abuts against the annular boss at the top end of the valve core 20, and the bottom end of the spring abuts against the bottom of the chamber (i.e. abuts against the valve body 10). The spring is located in the chamber of the valve body 10 with one end in contact with the valve core 20 and the other end in contact with the valve body 10. When hydraulic oil applies pressure to the spool 20, the spring is compressed. The spring provides a reaction force to the spool 20, ensuring that the spool 20 can return to its original position when the hydraulic oil pressure of the pilot gallery decreases or disappears. In addition, the spring rate and size are selected to ensure stable movement of the spool 20 under different operating conditions.

It will be appreciated that the pilot portion 40 includes a pilot oil passage, an oil passing gap is provided between the spool 20 and the inner wall surface of the valve body 10, the oil passing gap is communicated with the pilot oil passage, and the spool 20 is pressed by hydraulic oil in the pilot oil passage to move toward a direction approaching the feedback rod 30. The spool 20 has a difference in area at the end of the oil passing gap, that is, the upper end is larger than the lower end, so that the spool 20 receives a downward force by the hydraulic oil of the pilot oil passage. It is ensured that the valve spool 20 can be pushed all the time under the action of hydraulic oil.

It will be appreciated that, as shown in fig. 2, the first oil guiding channel 201 is a first oil guiding channel provided on a circumferential side wall of the valve core 20, and the second oil guiding channel 202 is a second oil guiding channel provided on a circumferential side wall of the valve core 20, and in the first working state, the first oil guiding channel communicates the high-pressure oil channel 12 with the working oil channel 13, and in the second working state, the second oil guiding channel communicates the drain oil channel 14 with the working oil channel 13. The valve core 20 is provided with a first oil-passing groove and a second oil-passing groove on the circumferential side wall, and the two oil-passing grooves can be respectively communicated with or disconnected from an oil passage on the valve body 10 according to the position of the valve core 20. In the first operating state, hydraulic oil flows in from the high-pressure oil passage 12, and the valve spool 20 is positioned such that the first oil passage communicates with the high-pressure oil passage 12 and the working oil passage 13. This causes hydraulic oil to flow into the working oil passage 13, thereby controlling the swash plate angle of the hydraulic motor to be increased (as shown in fig. 3). In the second operating state, hydraulic oil needs to flow out of the working oil passage 13. At this time, the position adjustment of the valve spool 20 causes the second oil passage to communicate with the drain oil passage 14 and the working oil passage 13, allowing hydraulic oil to flow from the working oil passage 13 into the drain oil passage 14 through the second oil passage, thereby reducing the swash plate angle (as shown in fig. 4).

Specifically, the first oil through groove and the second oil through groove are both in an annular groove shape. Two annular grooves, namely a first oil passage groove and a second oil passage groove, are designed on the circumferential side wall of the valve core 20. These annular grooves provide a continuous and uniform flow path for the hydraulic oil. Due to the annular design, these oil grooves may provide oil flow passages throughout the circumference of the spool 20, thereby providing a greater oil flow area and reducing flow resistance.

In some embodiments, the variable mechanism 100 further includes a stop collar 70, the stop collar 70 being removably disposed within the receiving cavity 16, the feedback rod 30 being connected to the stop collar 70 at an end thereof exposed from the receiving cavity, the stop collar 70 defining axial movement of the valve core 20. The stop collar 70 may be connected to the interior of the receiving chamber 16 by threads, a snap fit, a retainer ring, or other suitable connection means to ensure that it is secure and not easily removed. As hydraulic oil moves the spool 20, the spool 20 will slide in its axial direction until it hits the stop collar 70. This ensures that the spool 20 does not fail or fail due to excessive movement. In addition, the feedback rod 30 is connected with the limiting ring 70, so that the feedback rod 30 and the accommodating cavity 16 are relatively fixed, and when the hydraulic oil in the oil storage cavity 21 increases, the feedback rod 30 is not moved, and the valve core 20 moves in a direction away from the feedback rod 30. Finally, since the stop collar 70 is of a removable design, the feedback rod 30 can be easily replaced or maintained.

Specifically, the limiting ring 70 is provided with a plurality of through holes, and the oil drain passage 14 is communicated with the working oil passage 13 through the through holes. When the spool 20 moves to the position of the second operating state, the working oil passage 13 and the drain oil passage 14 may communicate through the through hole in the retainer ring 70. Since the plurality of through holes provide the oil flow passage, the hydraulic oil can flow more uniformly and more rapidly, thereby improving the response speed of the valve.

In some embodiments, a sealing ring is disposed at one end of the feedback rod 30 that is received in the oil storage chamber 21, so as to ensure that hydraulic oil in the oil storage chamber 21 cannot leak. The sealing ring is typically made of rubber, polytetrafluoroethylene or other suitable sealing material to ensure a good seal with the feedback rod 30 and the inner wall of the reservoir 21. The design and size of the sealing ring matches the diameters of the oil reservoir 21 and the feedback rod 30, ensuring an effective seal.

In some embodiments, along the axial direction of the valve core 20, annular sealing bands 22 are respectively arranged on the circumferential side walls of the valve core 20, which are close to two sides of the second feedback oil passage 23, so that effective sealing between the second feedback oil passage 23 and the pilot oil passage or the high-pressure oil passage 12 is ensured, and hydraulic oil is prevented from being mixed. The annular sealing band 22 provides an isolation area for the second feedback oil passage 23, ensuring that hydraulic oil can only flow through a predetermined path.

Specifically, the top of the valve body 10 is provided with a rear end cover 15, and a screw hole is formed, and the screw hole is matched with the plug 60, so that the valve core 20 can be conveniently taken out or installed. When the valve core 20 needs to be checked, maintained or replaced, only the plug 60 needs to be unscrewed, and then the rear end cap 15 is removed, so that the valve core 20 is easily taken out. After maintenance or replacement of the valve core 20 is completed, the rear end cap 15 can be reinstalled and the plug 60 screwed on to ensure that the hydraulic system is again closed. This allows for easy and quick replacement and maintenance of the spool 20 without the need to disassemble the entire hydraulic variable valve, reducing maintenance costs.

It is to be understood that the working oil passage 13 includes a first working oil passage 131 and a second working oil passage 132, and the first working oil passage 131 and the second working oil passage 132 are disposed perpendicular to each other and communicate with each other. The perpendicular and intersecting working oil channels 13 simplify the layout of the hydraulic system and save space.

Specifically, a control valve may be disposed at the junction of the first working oil passage 131 and the second working oil passage 132 for controlling the flow rate of hydraulic oil.

The present embodiment also proposes a walking motor including:

the variable mechanism 100 comprises a shell, a swash plate, pistons and the variable mechanism 100, wherein the swash plate is arranged in the shell, the pistons are connected with the swash plate, a working oil duct 13 of the variable mechanism 100 is connected with the pistons, and hydraulic oil of the working oil duct 13 pushes the pistons to jack up the swash plate to control the angle of the swash plate.

Specifically, the pistons and the swash plate may be connected in a rod shape, so that the pistons can directly push the swash plate to rotate under the action of hydraulic oil. The angle of the swash plate may be varied according to the position change of the pistons, thereby adjusting the displacement and rotational speed of the motor.

It will be appreciated that the angle of the swash plate determines the displacement of the hydraulic motor. When the swash plate is completely vertical (angle 0 deg.), the distance of movement of the plunger is minimal, and therefore the displacement of the motor is zero. This means that the motor does not produce any output. As the angle of the swash plate increases, the moving distance of the plunger increases, thereby increasing the displacement of the motor. When the swash plate reaches its maximum inclination angle, the displacement of the motor also reaches a maximum. Displacement refers to the volume of hydraulic oil displaced per revolution of the travel motor. If the input hydraulic oil flow remains unchanged, the greater the displacement of the motor, the lower its rotational speed and vice versa. Indirectly, the angle of the swash plate also affects the rotational speed of the motor. As previously mentioned, the swash plate angle determines the displacement of the motor. Thus, as the swash plate angle increases, the displacement also increases, which will result in a decrease in the rotational speed of the motor (assuming the input flow remains unchanged). Conversely, if the swash plate angle is reduced, the displacement is also reduced, resulting in an increase in rotational speed.

The embodiment also provides walking equipment, which comprises the walking motor.

Specifically, the walking device may be an excavator, and the walking motor may power a track or wheels of the excavator, so that the walking device may be moved in a construction site, a mine or other workplace.

In particular, the travelling devices may be loaders, which require rapid movements on the site, for which the travelling motor provides the necessary thrust.

In particular, the walking device may be an agricultural machine, such as a harvester, tractor, etc., which works in farmlands, requiring strong power and good low speed control.

Specifically, the walking equipment can be a crawler-type robot, and the power provided by the walking motor can enable the robot to move in various terrains in special occasions such as exploration or disaster relief.

In particular, the travelling device may be road engineering equipment, such as road pavers, road rollers etc., which are used in road construction, for which the travelling motor provides a stable and powerful power.

In particular, the travelling apparatus may be a mining apparatus, and in mine or underground operations, the travelling motor provides the necessary thrust to the apparatus to assist its movement in difficult terrain.

Specifically, the walking device can be airport ground service equipment, and the hydraulic motor provides power for equipment such as aircraft tractors, luggage transfer vehicles and the like to help the equipment to move on busy runways and parking spots.

The present utility model is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present utility model are intended to be included in the scope of the present utility model. Therefore, the protection scope of the utility model is subject to the protection scope of the claims.

Claims (10)

1. A variable mechanism, comprising:

the high-pressure oil duct, the oil drain duct, the first feedback oil duct and the working oil duct are arranged on the valve body, and a containing cavity is formed in the valve body;

the valve core is arranged in the accommodating cavity in a sliding manner, an oil storage cavity is formed in the valve core, a second feedback oil duct communicated with the oil storage cavity is formed in the valve core, and a first oil guide channel and a second oil guide channel are also formed in the valve core;

the feedback rod is inserted into the oil storage cavity at least partially and is connected with the inner wall of the oil storage cavity in a sealing way;

the pilot part is arranged in the valve body and used for driving the valve core to move towards the direction approaching the feedback rod;

when the valve is in a first working state, the pilot part controls the valve core to move along the direction approaching to the feedback rod, so that the high-pressure oil channel is communicated with the working oil channel through the first oil guide channel;

when the valve is in the second working state, the first feedback oil duct is communicated with the second feedback oil duct, and the valve core is driven to move towards the direction away from the feedback rod, so that the oil drain duct is communicated with the working oil duct through the second oil guide channel.

2. The variable mechanism of claim 1, wherein the pilot portion includes a pilot oil passage, an oil passing gap is provided between one end of the valve element and an inner wall surface of the valve body, and the oil passing gap is in communication with the pilot oil passage.

3. The variable displacement mechanism of claim 1, wherein the first oil guide passage comprises a first oil passage groove provided in a circumferential surface of the spool;

and/or the second oil guide channel comprises a second oil vent groove arranged on the circumferential surface of the valve core.

4. A variable mechanism as claimed in claim 3, wherein the first and second oil grooves are each in the form of an annular groove.

5. The variable mechanism of any one of claims 1-4, further comprising a stop collar removably disposed within the receiving cavity, the feedback rod being connected to an inner wall surface of the receiving cavity by the stop collar.

6. The variable mechanism of claim 5, wherein the stop collar is provided with a plurality of through holes, and the oil drain passage is communicated with the working oil passage through the through holes.

7. The variable displacement mechanism according to any one of claims 1 to 4, further comprising an elastic portion, wherein both ends of the elastic portion are respectively abutted against the valve element and the valve body, and the elastic portion is in a compressed state or in a stretched state when the valve element is moved in a direction approaching the feedback lever.

8. The variable displacement mechanism according to any one of claims 1 to 4, wherein annular seal strips are provided on circumferential side walls of the spool adjacent to both sides of the second feedback oil passage in the axial direction of the spool.

9. A travel motor, comprising:

a housing;

the swash plate is arranged in the shell;

the piston is connected with the swash plate;

the variable mechanism according to any one of claims 1 to 8, wherein a working oil passage of the variable mechanism is connected to the piston, and hydraulic oil of the working oil passage urges the piston to jack up the swash plate for controlling an angle of the swash plate.

10. A walking apparatus comprising the walking motor as claimed in claim 9.