CN219282130U

CN219282130U - Swash plate variable mechanism, hydraulic motor and engineering machinery

Info

Publication number: CN219282130U
Application number: CN202320385851.7U
Authority: CN
Inventors: 曹清洲; 张文兰; 朱睿
Original assignee: HANGZHOU LILONG HYDRAULIC CO LTD
Current assignee: HANGZHOU LILONG HYDRAULIC CO LTD
Priority date: 2023-02-27
Filing date: 2023-02-27
Publication date: 2023-06-30
Anticipated expiration: 2033-02-27

Abstract

The utility model provides a swash plate variable mechanism, a hydraulic motor and engineering machinery, and relates to the technical field of hydraulic motors. The swashplate variable mechanism comprises a swinging seat, a swashplate and variable pistons, and two swinging fulcrums are arranged on the swinging seat; the swash plate is arranged on the swinging seat in a swinging way and is in butt joint with the two swinging fulcrums; the variable piston is movably arranged on the swinging seat, the variable piston and the swinging supporting points are oppositely arranged on two sides of the center of the swash plate, the two swinging supporting points are symmetrically distributed about the variable piston, the variable piston is abutted with the swash plate, and the variable piston is suitable for pushing the swash plate to swing around the swinging supporting points. The utility model can solve the problem of unstable operation of the hydraulic motor caused by using a plurality of variable pistons in the swash plate axial plunger hydraulic motor in the prior art, and has the effect of ensuring the stable operation of the hydraulic motor.

Description

Swash plate variable mechanism, hydraulic motor and engineering machinery

Technical Field

The utility model relates to the technical field of hydraulic motors, in particular to a swash plate variable mechanism, a hydraulic motor and engineering machinery.

Background

The hydraulic walking hydraulic motor is one of the most widely used hydraulic elements in the fields of modern hydraulic transmission and engineering machinery, wherein the walking hydraulic motor and a speed reducer are commonly used in crawler driving, and the walking hydraulic motor adopts a high-speed small-torque walking mode under simple working conditions such as mild road conditions and the like according to the walking speed requirement of the engineering machinery, so that the efficiency is improved; under the working conditions of large gradient, complex road conditions, ascending slope and the like, the hydraulic motor adopts a low-speed large-torque walking mode, and is safe, reliable and powerful. When the hydraulic motor for walking is switched between the torque and the torque, a reliable and fast-switchable swash plate variable mechanism is needed.

The swash plate type axial plunger hydraulic motor in the current market comprises two or more variable pistons, and the variable pistons push the swash plate to swing, so that the displacement of the hydraulic motor is changed. For prior art, a plurality of variable pistons are symmetrically distributed on high pressure side and low pressure side, when the swash plate swings, there is pressure difference between high pressure side and low pressure side, and when the variable pistons push the swash plate to swing, there is eccentric problem, and a overturning moment is applied to the swash plate, so that the operation of the hydraulic motor is unstable.

Disclosure of Invention

The technical problem to be solved by the utility model is to overcome the defect that the swash plate axial plunger hydraulic motor in the prior art uses a plurality of variable pistons to cause unstable operation of the hydraulic motor, so as to provide a swash plate variable mechanism, the hydraulic motor and engineering machinery.

In order to solve the problems, a first aspect of the utility model provides a swashplate variable mechanism, which comprises a swashplate seat, a swashplate and variable pistons, wherein two swashplate fulcrums are arranged on the swashplate seat; the swash plate is arranged on the swinging seat in a swinging way and is in butt joint with the two swinging fulcrums; the variable piston is movably arranged on the swinging seat, the variable piston and the swinging supporting points are oppositely arranged on two sides of the center of the swash plate, the two swinging supporting points are symmetrically distributed about the variable piston, the variable piston is abutted with the swash plate, and the variable piston is suitable for pushing the swash plate to swing around the swinging supporting points.

Optionally, a first limit groove is formed in the swash plate, the bottom surface of the first limit groove is a curved surface, the first end surface of the variable piston is a curved surface matched with the bottom surface of the first limit groove, and the first end of the variable piston is abutted to the first limit groove.

Optionally, the swing seat is connected with a central rotating shaft, the center of the swash plate is provided with a shaft hole, the swash plate is sleeved on the central rotating shaft, and the axis of the variable piston is arranged at an angle with the axis of the central rotating shaft.

Optionally, a first mounting hole is formed in the swing seat, the variable piston comprises a piston body and an elastic piece, the elastic piece is arranged in the first mounting hole, a first end of the piston body is abutted to the first limiting groove, and a second end of the piston body is connected with the elastic piece.

Optionally, the second end of the piston body is provided with a groove extending along the axial direction of the piston body, one end of the elastic piece is arranged in the groove, and the other end of the elastic piece is abutted with the hole bottom of the first mounting hole.

Optionally, the swing seat includes the casing, is equipped with the limit structure that is used for restricting the top stroke of variable piston between casing and the sloping cam plate, and limit structure is close to variable piston setting.

Optionally, the limit structure includes the first spacing face of locating on the sloping cam plate and locates on the casing and with first spacing face complex second spacing face, the one side of deviating from the variable piston is located to first spacing face.

Optionally, the swing fulcrum comprises a support column and a support ball head arranged on the support column, the swash plate is provided with a second limit groove, and the support ball head is in butt fit with the second limit groove; the swing seat is provided with a second mounting hole, and the support column is arranged in the second mounting hole.

Optionally, the support bulb is hemisphere structure, is equipped with the heliciform oil groove that sets up around the axis of support column on the hemisphere of support bulb.

Optionally, the swing fulcrum further includes an oil hole penetrating through the support column and the support ball head along an axial direction, and an end of the oil groove extends to an end of the oil hole and is adapted to be communicated with the oil hole.

A second aspect of the utility model provides a hydraulic motor comprising the swash plate variable mechanism of any one of the above aspects.

A third aspect of the utility model provides a construction machine comprising the hydraulic motor of the above technical scheme.

The utility model has the following advantages:

1. by utilizing the technical scheme of the utility model, the swash plate is abutted with the two swing fulcrums, and the swing fulcrums play a supporting role in swinging of the swash plate, so that the swash plate can swing around the swing fulcrums; because the variable pistons are movable and are abutted with the swash plate, the variable pistons can push the swash plate to swing around the swing pivot, and because only one variable piston is arranged, and the two swing pivot are symmetrically distributed about the variable pistons, namely the variable pistons are positioned between the high-pressure side and the low-pressure side, the problem of eccentricity does not exist, and therefore, the variable pistons cannot generate overturning force on the swash plate in the swinging process of the swash plate, and the stable operation of the hydraulic motor is ensured. In addition, a plurality of variable pistons are arranged in the prior art, so that a corresponding number of mounting holes for mounting the variable pistons are required to be arranged on the swinging seat, the depth of the mounting holes is large, the requirements are high, the machining is difficult, and the production cost is high.

2. The axis of the variable piston is arranged at an angle with the axis of the central rotating shaft, so that the abrasion problem caused by the radial force born by the variable piston can be effectively reduced, and enough axial force can be ensured to drive the swashplate to swing, thereby realizing variable.

3. Because the groove bottom surface of the first limit groove of the swash plate is a curved surface, the first end surface of the variable piston is a curved surface matched with the groove bottom surface of the first limit groove, the contact area between the variable piston and the swash plate can be increased, and the abrasion is reduced.

4. The first mounting hole is formed in the swing seat, the first end of the piston body is abutted to the first limit groove of the swash plate, and the second end of the piston body is connected with the elastic piece, so that the traditional sliding shoes and plungers are replaced.

5. The limiting structure is arranged between the shell of the swing seat and the swash plate, so that the pushing stroke of the variable pistons can be limited, the minimum displacement of the hydraulic motor is limited, the limiting structure is arranged close to the variable pistons, and the variable pistons can be prevented from damaging the swash plate when pushing the swash plate due to the lever principle.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present utility model, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 illustrates a cross-sectional view of a hydraulic motor provided by an embodiment of the present utility model in a large displacement state;

FIG. 2 shows an enlarged view of the structure at A in FIG. 1;

FIG. 3 illustrates a bottom view of a swash plate variable mechanism provided by an embodiment of the present utility model;

FIG. 4 is a perspective view showing a swash plate in a swash plate variable mechanism provided by an embodiment of the utility model;

FIG. 5 shows a cross-sectional view taken along B-B in FIG. 4;

FIG. 6 illustrates a perspective view of a variable piston in a swash plate variable mechanism provided by an embodiment of the present utility model;

FIG. 7 illustrates a cross-sectional view of a hydraulic motor provided in an embodiment of the present utility model in a small displacement state;

fig. 8 shows an enlarged view of the structure at C in fig. 7;

fig. 9 is a front view showing a swing fulcrum in a swash plate variable mechanism provided by an embodiment of the present utility model;

fig. 10 shows a top view of fig. 9.

Reference numerals illustrate:

1. a swinging seat; 11. a first mounting hole; 12. a second mounting hole; 13. a housing; 2. a swing fulcrum; 21. a support column; 22. supporting the ball head; 23. an oil groove; 24. oil holes; 3. a swash plate; 31. a first limit groove; 32. the second limit groove; 33. a shaft hole; 4. a variable piston; 41. a piston body; 42. an elastic member; 5. a central spindle; 6. a limit structure; 61. a first limiting surface; 62. the second limiting surface; 7. a plunger assembly; 8. and a variable oil path.

Detailed Description

The following description of the embodiments of the present utility model will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the utility model are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In the description of the present utility model, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In addition, the technical features of the different embodiments of the present utility model described below may be combined with each other as long as they do not collide with each other.

For the purpose of illustrating the concepts of the utility model, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

Example 1

A variable displacement mechanism of a swash plate is suitable for a variable displacement hydraulic motor. Referring to fig. 1 to 10, the swash plate variable mechanism comprises a swing seat 1, a swash plate 3 and variable pistons 4, wherein two swing fulcra 2 are arranged on the swing seat 1; the swash plate 3 is arranged on the swing seat 1 in a swinging manner, and the swash plate 3 is in abutting connection with the two swing fulcrums 2; the variable piston 4 is movably arranged on the swinging seat 1, the variable piston 4 and the swinging supporting points 2 are oppositely arranged on two sides of the center of the swash plate 3, the two swinging supporting points 2 are symmetrically distributed about the variable piston 4, the variable piston 4 is abutted with the swash plate 3, and the variable piston is suitable for pushing the swash plate 3 to swing around the swinging supporting points 2.

By utilizing the technical scheme of the utility model, the swash plate 3 is abutted with the two swing fulcrums 2, and the swing fulcrums 2 play a supporting role on the swing of the swash plate 3, so that the swash plate 3 can swing around the swing fulcrums 2; because the variable piston 4 is movable and is abutted against the swash plate 3, the variable piston 4 can push the swash plate 3 to swing around the swing pivot 2, and because only one variable piston 4 is arranged, and the two swing pivot 2 are symmetrically distributed about the variable piston 4, namely positioned between the high pressure side and the low pressure side, the problem of eccentricity does not exist, and therefore, in the swinging process of the swash plate 3, the variable piston 4 cannot generate overturning force on the swash plate 3, and the stable operation of the hydraulic motor is ensured. In addition, since the plurality of variable pistons 4 are arranged in the prior art, the corresponding number of mounting holes for mounting the variable pistons 4 are required to be arranged on the swinging seat 1, the depth of the mounting holes is large, the requirements are high, the machining is difficult, and the production cost is high.

Specifically, referring to fig. 3, in the present embodiment, the line connecting the two swing fulcrums 2 is the swing axis of the swash plate 3, the line connecting the center of the variable piston 4 and the center of the swash plate 3 is the first line, and the first line is perpendicular to the swing axis, that is, the two swing fulcrums 2 are arranged axisymmetrically with respect to the first line.

Optionally, referring to fig. 1, a central rotating shaft 5 is connected to the swing seat 1, a shaft hole 33 is arranged in the center of the swash plate 3, the swash plate 3 is sleeved on the central rotating shaft 5, and the axis of the variable piston 4 is arranged at an angle with the axis of the central rotating shaft 5. The arrangement can effectively reduce the abrasion problem caused by the radial force born by the variable piston 4, ensure enough axial force to drive the swash plate 3 to swing, and realize the variable.

Optionally, the angle between the axis of the variable piston 4 and the axis of the central spindle 5 is less than 10 °.

Optionally, referring to fig. 4 and 5, the swash plate 3 is provided with a first limiting groove 31, the bottom surface of the first limiting groove 31 is a curved surface, the first end surface of the variable piston 4 is a curved surface matched with the bottom surface of the first limiting groove 31, and the first end of the variable piston 4 is abutted in the first limiting groove 31. The variable piston 4 has a cylindrical structure, and the end of the variable piston 4 is a curved surface, as shown in fig. 6.

When the hydraulic motor is variable, the variable piston 4 pushes the swash plate 3 to swing around the swing fulcrum 2, extrusion and friction are generated between the swash plate 3 and the variable piston 4, and thus the contact area between the variable piston 4 and the swash plate 3 can be increased, and abrasion is reduced.

Alternatively, referring to fig. 1 or 7, the swing seat 1 is provided with a first mounting hole 11, the variable piston 4 includes a piston body 41 and an elastic member 42, the elastic member 42 is disposed in the first mounting hole 11, a first end of the piston body 41 abuts against the first limiting groove 31, and a second end of the piston body 41 is connected with the elastic member 42. According to the swash plate variable mechanism provided by the utility model, the variable piston 4 adopts the piston body 41 to replace the traditional sliding shoes and plungers, so that the structure is simpler, and the operation is more reliable.

Alternatively, referring to fig. 1 or 7, the second end of the piston body 41 is provided with a groove extending in the axial direction thereof, one end of the elastic member 42 is provided in the groove, and the other end of the elastic member 42 abuts against the hole bottom of the first mounting hole 11. Through setting up elastic component 42, elastic component 42 can exert elastic force to piston body 41, makes the first end of piston body 41 contact with sloping cam plate 3 all the time, simultaneously, also can reduce piston body 41 and cause the impact to sloping cam plate 3 under the effect of variable oil pressure, reduces wearing and tearing. Alternatively, the resilient member 42 comprises a spring or other structure having an elastic restoring force.

Optionally, the swing seat 1 includes a housing 13, and a limiting structure 6 for limiting the pushing stroke of the variable piston 4 is arranged between the housing 13 and the swash plate 3, and the limiting structure 6 is arranged close to the variable piston 4. The limit structure 6 can limit the pushing stroke of the variable piston 4, thereby limiting the minimum displacement of the hydraulic motor. Specifically, when the included angle between the axis of the swash plate 3 and the axis of the central rotating shaft 5 is larger, the displacement of the hydraulic motor adopting the swash plate variable mechanism is larger, the output torque is larger, and the output rotating speed is lower; conversely, the smaller the angle between the axis of the swash plate 3 and the axis of the central rotary shaft 5, the smaller the displacement of the hydraulic motor employing the swash plate variable mechanism, the smaller the output torque, and the higher the output rotation speed. In fig. 1, the lower surface of the swash plate 3 is in contact with the upper surface of the swash plate seat 1, and the swash plate 3 swings to a maximum angle, and in this case, the maximum displacement operation state is achieved.

Optionally, referring to fig. 1, in combination with fig. 2, the limit structure 6 includes a first limit surface 61 provided on the swash plate 3 and a second limit surface 62 provided on the housing 13 and engaged with the first limit surface 61, where the first limit surface 61 is provided on a surface of the swash plate 3 facing away from the variable piston 4. When the swash plate 3 swings upward until the first limit surface 61 of the swash plate 3 abuts against the second limit surface 62 of the housing 13, as shown in fig. 7 and 8, the swash plate 3 is limited, at this time, the included angle between the axis of the swash plate 3 and the axis of the central rotating shaft 5 is minimum, and the displacement of the hydraulic motor adopting the swash plate variable mechanism provided by the embodiment is minimum, which is the minimum displacement working state. Specifically, the inner wall of the housing 13 is provided with a protrusion, and the end surface of the protrusion facing the swash plate 3 constitutes a second limit surface 62.

In the prior art, the limit structure 6 is arranged on the side where the swing fulcrum 2 is arranged, the lower surface of the swash plate 3 and the upper surface of the swing seat 1 are in butt joint limit, so that the swash plate 3 swings to the minimum displacement working position, because the limit structure 6 is far away from the variable piston 4, and the swash plate 3 swings around the swing fulcrum 2, the force arm of the variable piston 4 is longer due to the lever principle, the variable piston 4 can apply larger moment to the swash plate 3, and the swash plate 3 is easy to damage. In the swash plate variable mechanism provided by the embodiment, the limiting structure 6 is arranged close to the variable pistons 4, and the variable pistons 4 can be directly blocked on the same side by the limiting structure 6 when being pushed upwards, so that the variable pistons 4 are effectively prevented from damaging the swash plate 3 when pushing the swash plate 3.

Alternatively, referring to fig. 1 or 7, the swing fulcrum 2 includes a support column 21 and a support ball 22 disposed on the support column 21, the swash plate 3 is provided with a second limit groove 32, and the support ball 22 is in abutting fit with the second limit groove 32; the swing seat 1 is provided with a second mounting hole 12, and the support column 21 is arranged in the second mounting hole 12. Specifically, the bottom surface of the second limit groove 32 of the swash plate 3 is a spherical surface that mates with the support ball 22, which can be said to be a ball socket.

Alternatively, referring to fig. 9 and 10, the support ball 22 has a hemispherical structure, and a spiral oil groove 23 provided around the axis of the support column 21 is provided on the hemispherical surface of the support ball 22. When the hydraulic motor is variable, the swash plate 3 swings around the swing pivot 2, a strong extrusion and friction effect is generated between the swash plate 3 and the swing pivot 2, namely, extrusion and friction are generated between the second limit groove 32 and the supporting ball head 22, hydraulic oil exists in the oil groove 23, the hydraulic oil is attached to the surfaces of the second limit groove 32 and the supporting ball head 22 of the swash plate 3 along with the swing of the swash plate 3, an oil film is formed between the two surfaces, a lubrication effect is achieved, the swing flexibility of the swash plate 3 can be improved, and the service life is prolonged.

Optionally, the swing fulcrum 2 further includes an oil hole 24 penetrating the support column 21 and the support ball 22 in the axial direction, and an end of the oil groove 23 extends toward the top of the support ball 22 and is adapted to communicate with the oil hole 24. Specifically, the support column 21 and the second mounting hole 12 are in interference fit, and in the assembly process, the oil through hole 24 is arranged on the swing pivot 2, so that exhaust is facilitated, and the installation of the swing pivot 2 is facilitated.

Alternatively, referring to fig. 10, the top of the supporting ball 22 is provided as a plane, and one end of the oil groove 23 extends to the plane. This arrangement is advantageous for the oil in the oil groove 23 and the oil passing hole 24 to communicate with each other, and the oil in the oil passing hole 24 is advantageous for cooling due to frictional heat generation.

Example 2

A hydraulic motor comprising the swash plate variable mechanism described in embodiment 1.

Specifically, in this embodiment, the hydraulic motor is a swash plate type axial plunger hydraulic motor.

Specifically, referring to fig. 1, the housing 13 is a hydraulic motor housing, one side of the swash plate 3, which is away from the variable piston 4, is connected with a plurality of plunger assemblies 7, the hydraulic motor housing is provided with a working port a, a working port B and a variable oil path 8, one end of the variable oil path 8 is connected with an oil inlet, and the other end of the variable oil path 8 is communicated with the bottom of the first mounting hole 11, so that the inner cavity of the first mounting hole 11 is communicated with the oil inlet through the variable oil path 8. Wherein, work port A and work port B can both be the oil inlet.

Working principle:

(1) Under the action of the hydraulic motor without external control hydraulic oil, the swing angle of the swash plate 3 is maximum, and as shown in fig. 1, the displacement of the hydraulic motor is maximum at the moment, and the hydraulic motor is in a low-speed walking state.

(2) When the hydraulic motor is under the action of external control oil and is in a working state, the external control oil pushes the high-low speed switching control valve core, working oil of the working port A or the working port B enters the inner cavity of the first mounting hole 11 through the variable oil way 8, the variable piston 4 is pushed to move upwards, so that the swash plate 3 is pushed to swing around the swing fulcrum 2, when the first limiting surface 61 of the swash plate 3 is in contact with the second limiting surface 62 of the shell 13, the hydraulic motor reaches the minimum displacement, and the hydraulic motor is in a high-speed walking state.

Example 3

A construction machine comprising the hydraulic motor of embodiment 2.

According to the above description, the present patent application has the following advantages:

1. according to the swash plate variable mechanism provided by the embodiment of the utility model, only one variable piston 4 is arranged, and the two swing fulcra 2 are symmetrically distributed about the variable piston 4, namely, the variable piston 4 is positioned between a high-pressure side and a low-pressure side, so that the problem of eccentricity does not exist, and therefore, the variable piston 4 cannot generate overturning force on the swash plate 3 in the swinging process of the swash plate 3, and the stable operation of the hydraulic motor is ensured;

2. only one variable piston 4 is arranged, so that only one mounting hole is needed to be arranged on the swinging seat 1, and the production cost is reduced;

3. the axis of the variable piston 4 is arranged at an angle with the axis of the central rotating shaft 5, so that the abrasion problem caused by the radial force borne by the variable piston 4 can be effectively reduced, and enough axial force can be ensured to drive the swash plate 3 to swing, so that the variable is realized;

4. the bottom surface of the first limit groove 31 of the swash plate 3 is a curved surface, and the first end surface of the variable piston 4 is a curved surface matched with the bottom surface of the first limit groove 31, so that the contact area between the variable piston 4 and the swash plate 3 can be increased, and the abrasion is reduced;

5. in the variable piston, the piston body 41 replaces the traditional sliding shoe and plunger structure, and the swash plate variable mechanism provided by the utility model is simpler in structure and more reliable in operation;

6. the limiting structure 6 for limiting the minimum displacement of the hydraulic motor is arranged close to the variable piston 4, so that the variable piston 4 can be prevented from damaging the swash plate 3 when pushing the swash plate 3 due to the lever principle.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the utility model.

Claims

1. A swash plate variable mechanism, comprising:

the swinging seat (1), two swinging fulcra (2) are arranged on the swinging seat (1);

a swash plate (3) swingably provided on the swing seat (1), the swash plate (3) abutting against the two swing fulcrums (2);

the variable pistons (4) are movably arranged on the swinging seat (1), the variable pistons (4) and the swinging supporting points (2) are oppositely arranged on two sides of the center of the swash plate (3), the two swinging supporting points (2) are symmetrically distributed relative to the variable pistons (4), the variable pistons (4) are abutted with the swash plate (3) and are suitable for pushing the swash plate (3) to swing around the swinging supporting points (2).

2. The swash plate variable mechanism according to claim 1, wherein the swing seat (1) is connected with a central rotating shaft (5), a shaft hole (33) is formed in the center of the swash plate (3), the swash plate (3) is sleeved on the central rotating shaft (5), and the axis of the variable piston (4) is arranged at an angle with the axis of the central rotating shaft (5).

3. The swash plate variable mechanism according to claim 1 or 2, wherein a first limit groove (31) is formed in the swash plate (3), the groove bottom surface of the first limit groove (31) is a curved surface, the first end surface of the variable piston (4) is a curved surface matched with the groove bottom surface of the first limit groove (31), and the first end of the variable piston (4) is abutted in the first limit groove (31).

4. A swash plate variable mechanism according to claim 3, wherein the swing seat (1) is provided with a first mounting hole (11), the variable piston (4) comprises a piston body (41) and an elastic member (42), the elastic member (42) is arranged in the first mounting hole (11), a first end of the piston body (41) is abutted to the first limit groove (31), and a second end of the piston body (41) is connected with the elastic member (42).

5. Swash plate variable mechanism according to claim 1 or 2, characterized in that the swing base (1) comprises a housing (13), a limit structure (6) for limiting the pushing stroke of the variable piston (4) is arranged between the housing (13) and the swash plate (3), and the limit structure (6) is arranged close to the variable piston (4).

6. The swash plate variable mechanism according to claim 5, characterized in that the limit structure (6) comprises a first limit surface (61) provided on the swash plate (3) and a second limit surface (62) provided on the housing (13) and cooperating with the first limit surface (61), the first limit surface (61) being provided on a side of the swash plate (3) facing away from the variable piston (4).

7. The swash plate variable mechanism according to claim 1 or 2, wherein the swing fulcrum (2) comprises a support column (21) and a support ball head (22) arranged on the support column (21), a second limit groove (32) is arranged on the swash plate (3), and the support ball head (22) is in abutting fit with the second limit groove (32); the swinging seat (1) is provided with a second mounting hole (12), and the support column (21) is arranged in the second mounting hole (12).

8. The swash plate variable mechanism according to claim 7, wherein the support ball (22) has a hemispherical structure, and a spiral oil groove (23) provided around the axis of the support column (21) is provided on a hemispherical surface of the support ball (22);

or, the swing fulcrum (2) further comprises an oil through hole (24) penetrating through the support column (21) and the support ball head (22) along the axial direction, and the end part of the oil groove (23) extends to the top of the support ball head (22) and is suitable for being communicated with the oil through hole (24).

9. A hydraulic motor comprising the swash plate variable mechanism of any one of claims 1 to 8.

10. A construction machine comprising the hydraulic motor according to claim 9.