Servo piston, servo variable mechanism and hydraulic motor

Abstract

The utility model relates to the technical field of hydraulic motors, in particular to a servo piston, a servo variable mechanism and a hydraulic motor, the servo piston comprises a piston body, a plurality of pressure equalizing grooves are formed in the outer side wall of the piston body, the pressure equalizing grooves are continuous in the circumferential direction of the piston body, and the pressure equalizing grooves are distributed at intervals in the axial direction of the piston body. At least one pressure equalizing groove is arranged to be of a spiral structure, the piston body is further provided with a middle oil channel and damping holes, the damping holes are used for communicating the middle oil channel with one pressure equalizing groove, and the multiple damping holes are evenly distributed in the circumferential direction of the piston body. The pressure equalizing grooves are formed in the outer side wall of the piston body, the circumferential pressure of the piston body is balanced, the radial force of the piston is eliminated, at least one pressure equalizing groove is of a spiral structure, and the coverage area is larger. The middle oil duct is communicated with the pressure equalizing groove through the damping hole, the piston body can be lubricated, the pressure equalizing groove can store metal filings generated by abrasion, and oil pollution is avoided to a certain degree.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic motors, in particular to a servo piston, a servo variable mechanism and a hydraulic motor. Background Art

[0002] The servo piston of the servo variable mechanism of the hydraulic motor in the prior art has errors in its geometric shape and size due to the influence of processing accuracy, and there is also an error in the relative position accuracy of the servo piston and the housing after the housing is assembled. When the hydraulic oil flows through the gap between the servo piston and the housing, a radial force is generated on the servo piston, causing friction resistance along the circumferential direction between the servo piston and the housing, and it is easy to wear. In addition, when the driving force of the servo piston is not enough to overcome the friction resistance, the servo piston will get stuck, which will slow down the response speed of the servo piston or reduce the response accuracy. Utility Model Content

[0003] The utility model aims to provide a servo piston, a servo variable mechanism and a hydraulic motor to solve the problem of radial force in the existing servo piston during its action.

[0004] The utility model provides a servo piston, comprising a piston body, wherein the outer side wall of the piston body is provided with a plurality of pressure equalizing grooves, the pressure equalizing grooves are continuous along the circumference of the piston body, the plurality of pressure equalizing grooves are distributed at intervals along the axial direction of the piston body, at least one pressure equalizing groove is arranged as a spiral structure, the piston body is further provided with an intermediate oil passage and a damping hole, the damping hole is used to connect the intermediate oil passage and one of the pressure equalizing grooves, the damping hole is arranged in plurality, and the plurality of damping holes are evenly distributed along the circumference of the piston body.

[0005] As a preferred technical solution for the servo piston, multiple pressure equalizing grooves include a first circular pressure equalizing groove, a second circular pressure equalizing groove and a spiral pressure equalizing groove. The first circular pressure equalizing groove and the second circular pressure equalizing groove are arranged as circular structures, and the spiral pressure equalizing groove is arranged as a spiral structure. The spiral pressure equalizing groove is located between the first circular pressure equalizing groove and the second circular pressure equalizing groove.

[0006] As a preferred technical solution for the servo piston, the plurality of damping holes are all connected to the first annular pressure equalizing groove.

[0007] As a preferred technical solution for the servo piston, there are two damping holes, which are symmetrically arranged.

[0008] As a preferred technical solution for the servo piston, the width of the first annular pressure-equalizing groove is greater than or equal to the aperture of the damping hole.

[0009] As a preferred technical solution for the servo piston, two ends of the spiral pressure-equalizing groove are respectively connected to the first annular pressure-equalizing groove and the second annular pressure-equalizing groove.

[0010] As a preferred technical solution for the servo piston, the width of the first annular pressure-equalizing groove, the width of the second annular pressure-equalizing groove and the width of the spiral pressure-equalizing groove are equal.

[0011] The utility model provides a servo variable mechanism, comprising a shell, an oil hole is arranged on the shell, and also comprises a sliding shoe and a servo piston of any of the above schemes, the piston body cooperates with the inner wall of the shell, the middle oil channel is connected with the oil hole, the sliding shoe comprises a ball head, the piston body is provided with a receiving groove matched with the ball head, and the receiving groove is connected with the middle oil channel.

[0012] As a preferred technical solution for the servo variable mechanism, the middle oil channel is arranged as a step-shaped structure, and the small end of the middle oil channel is connected to the accommodating groove.

[0013] The utility model provides a hydraulic motor, comprising a swash plate and a servo variable mechanism of any one of the above schemes, wherein a sliding shoe abuts against the swash plate, and the sliding shoe is used for changing the angle of the swash plate.

[0014] The beneficial effects of the utility model are:

[0015] The utility model provides a servo piston, wherein a plurality of equalizing pressure grooves are provided on the outer side wall of the piston body, thereby balancing the circumferential pressure of the piston body, thereby eliminating the radial force of the piston, and at least one equalizing pressure groove is provided in a spiral structure, with a larger coverage area. At the same time, a damping hole is provided to connect the intermediate oil channel with the equalizing pressure groove, so as to lubricate the piston body, and the equalizing pressure groove can also store metal chips generated by wear, thereby avoiding oil pollution to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the servo piston assembled on the hydraulic motor in the embodiment of the utility model;

[0017] Figure 2 This is a schematic diagram of the structure of the servo piston in the embodiment of the utility model;

[0018] Figure 3 A cross-sectional view of a servo piston in an embodiment of the utility model;

[0019] Figure 4 for Figure 3 A partial enlarged view of part A.

[0020] In the figure:

[0021] 100, housing; 200, swash plate;

[0022] 1. Piston body; 11. First annular pressure-equalizing groove; 12. Second annular pressure-equalizing groove; 13. Spiral pressure-equalizing groove; 14. Damping hole; 15. Intermediate oil channel; 2. Slipper. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solution of the utility model in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0026] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0027] like Figure 1-Figure 4As shown, the utility model provides a servo piston, which includes a piston body 1, and the outer side wall of the piston body 1 is provided with a plurality of equalizing pressure grooves, which are continuous along the circumference of the piston body 1. The plurality of equalizing pressure grooves are distributed at intervals along the axial direction of the piston body 1. Thus, the pressure of the servo piston is balanced at various locations along the circumference during the movement to eliminate radial force and avoid the problem of increased friction resistance or stuck. At the same time, the equalizing pressure groove can also store metal chips generated by wear and tear, and avoid oil pollution to a certain extent. The plurality of equalizing pressure grooves are distributed at intervals along the axial direction of the piston body 1, which can further ensure the pressure balance at various locations of the circumference of the piston body 1. At least one equalizing pressure groove is set as a spiral structure, which has a larger coverage area and a better balancing effect. The piston body 1 is also provided with an intermediate oil passage 15 and a damping hole 14, and the damping hole 14 is used to connect the intermediate oil passage 15 and one of the equalizing pressure grooves. The damping hole 14 is set as a plurality of damping holes 14 and the plurality of damping holes 14 are evenly distributed along the circumference of the piston body 1, and the damping hole 14 is used to provide oil to the equalizing pressure groove to lubricate the servo piston. Since the servo piston is only actuated when the displacement of the hydraulic motor needs to be adjusted, and it is controlled by pressure, that is, the pressure of the hydraulic oil suddenly increases at the moment when the servo piston starts to move. If only one damping hole 14 is provided, at the moment when the pressure suddenly increases, the hydraulic oil passes through one damping hole 14, which will cause uneven force on the periphery of the servo piston at that moment, causing the servo piston to be subjected to additional radial force. By providing a plurality of damping holes 14 evenly distributed along the circumference of the piston body 1, each damping hole 14 has hydraulic oil passing through, so that the periphery of the servo piston is evenly stressed and the servo piston is not subjected to radial force, thereby achieving the damping hole 14 providing oil to the pressure equalizing groove without subjecting the servo piston to additional radial force.

[0028] For further information, please refer to Figure 2-Figure 4 As shown, the plurality of pressure equalizing grooves include a first annular pressure equalizing groove 11, a second annular pressure equalizing groove 12 and a spiral pressure equalizing groove 13. The first annular pressure equalizing groove 11 and the second annular pressure equalizing groove 12 are both configured as annular structures, the spiral pressure equalizing groove 13 is configured as a spiral structure, and the spiral pressure equalizing groove 13 is located between the first annular pressure equalizing groove 11 and the second annular pressure equalizing groove 12, so that the first annular pressure equalizing groove 11, the spiral pressure equalizing groove 13 and the second annular pressure equalizing groove 12 arranged in sequence along the axial direction are formed on the outer peripheral surface of the piston body 1, and the spiral pressure equalizing groove 13 is arranged between the first annular pressure equalizing groove 11 and the second annular pressure equalizing groove 12, so that the balance of the circumferential pressure of the piston body 1 can cover a larger surface area.

[0029] Specifically, the two ends of the spiral pressure-equalizing groove 13 are connected to the first annular pressure-equalizing groove 11 and the second annular pressure-equalizing groove 12, respectively. Since there are multiple high-pressure areas and low-pressure areas on the outer peripheral surface of the piston body 1 due to the problem of matching accuracy, and the distribution of the high-pressure areas and the low-pressure areas is irregular and unpredictable. Therefore, by connecting the first annular pressure-equalizing groove 11, the spiral pressure-equalizing groove 13 and the second annular pressure-equalizing groove 12, the flow path of the hydraulic oil in the high-pressure area to the low-pressure area can be effectively shortened, and the balance of the oil on the outer peripheral surface of the piston body 1 can be achieved as soon as possible, thereby eliminating the radial force of the piston body 1 more quickly, so as to improve the response speed and response accuracy of the servo piston.

[0030] Optionally, the width of the first annular pressure equalizing groove 11, the width of the second annular pressure equalizing groove 12 and the width of the spiral pressure equalizing groove 13 are equal to avoid the problem of increased balancing time due to increased local flow resistance of the hydraulic oil at the connecting position, thereby further improving the response speed of the servo piston.

[0031] Furthermore, the first annular pressure-equalizing groove 11 and the second annular pressure-equalizing groove 12 are arranged in parallel, and the first annular pressure-equalizing groove 11 is parallel to the end face of the piston body 1. Multiple damping holes 14 are all connected to the first annular pressure-equalizing groove 11, ensuring that the force of the hydraulic oil at each damping hole 14 on the piston body 1 acts on the same point, rather than being distributed along the axial direction of the piston body 1, so as to avoid the piston body 1 from being subjected to bending moment and causing the cylindricity to deteriorate, thereby ensuring the matching accuracy of the piston body 1 and the housing 100. In other embodiments, multiple damping holes 14 can also be arranged to be connected to the second annular pressure-equalizing groove 12, and the positions of the first annular pressure-equalizing groove 11 and the second annular pressure-equalizing groove 12 can be adaptively adjusted according to needs, and multiple damping holes 14 can be selectively arranged to be all connected to the first annular pressure-equalizing groove 11 or all connected to the second annular pressure-equalizing groove 12, which will not be elaborated here.

[0032] Optionally, to avoid excessive loss of hydraulic oil pressure at the intermediate oil channel 15, the number of damping holes 14 is set to only two, and the two damping holes 14 are symmetrically arranged. In addition, the width of the first annular pressure equalizing groove 11 is greater than or equal to the aperture of the damping hole 14, thereby avoiding throttling at the connection position to cause pressure loss.

[0033] The utility model provides a servo variable mechanism, which includes a housing 100, and an oil hole is provided on the housing 100. It also includes a sliding shoe 2 and a servo piston, the piston body 1 of the servo piston is matched with the inner side wall of the housing 100, and the intermediate oil passage 15 is connected with the oil hole. The sliding shoe 2 includes a ball head, and the piston body 1 is provided with a receiving groove matched with the ball head, and the receiving groove is connected with the intermediate oil passage 15. The ball head is hinged in the receiving groove, and the sliding shoe 2 is pushed to move and swing by the movement of the piston body 1 in the housing 100. The intermediate oil passage 15 is set as a step-shaped structure, and the small end of the intermediate oil passage 15 is connected with the receiving groove. The oil pressure of the hydraulic oil directly acts on the local position of the ball head, so that the sliding shoe 2 is reliably pressed against the swash plate 200, and when the sliding shoe 2 pushes the swash plate 200 to change the angle, the ball head can be synchronously swung in the receiving groove to ensure that the sliding shoe 2 is in contact with the swash plate 200. By setting the servo piston in this embodiment, the probability of jamming during the variable adjustment process is reduced, thereby ensuring the response speed and response accuracy.

[0034] The utility model provides a hydraulic motor, including a swash plate 200 and a servo variable mechanism in this embodiment, wherein a sliding shoe 2 abuts against the swash plate 200, and the sliding shoe 2 is used to change the angle of the swash plate 200 to achieve a change in the displacement of the hydraulic motor. In order to improve the compactness of the structure, the servo variable mechanism is integrated on the housing of the hydraulic motor. By setting the servo variable mechanism in this embodiment, the speed and accuracy of the hydraulic motor displacement adjustment are improved.

[0035] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A servo piston, characterized in that: The invention comprises a piston body (1), wherein the outer wall of the piston body (1) is provided with a plurality of pressure equalizing grooves, wherein the pressure equalizing grooves are continuous along the circumference of the piston body (1), and the plurality of pressure equalizing grooves are distributed at intervals along the axial direction of the piston body (1), and at least one of the pressure equalizing grooves is arranged as a spiral structure. The piston body (1) is also provided with an intermediate oil passage (15) and a damping hole (14), wherein the damping hole (14) is used to connect the intermediate oil passage (15) and one of the pressure equalizing grooves, and the damping hole (14) is arranged in plurality, and the plurality of damping holes (14) are evenly distributed along the circumference of the piston body (1).

2. The servo piston according to claim 1, characterized in that: The plurality of pressure equalizing grooves include a first annular pressure equalizing groove (11), a second annular pressure equalizing groove (12) and a spiral pressure equalizing groove (13), and the spiral pressure equalizing groove (13) is located between the first annular pressure equalizing groove (11) and the second annular pressure equalizing groove (12).

3. The servo piston according to claim 2, characterized in that: The plurality of damping holes (14) are all in communication with the first annular pressure equalizing groove (11).

4. The servo piston according to claim 3, characterized in that: The number of the damping holes (14) is two, and the two damping holes (14) are symmetrically arranged.

5. The servo piston according to claim 3, characterized in that: The width of the first annular pressure equalizing groove (11) is greater than or equal to the diameter of the damping hole (14).

6. The servo piston according to claim 2, characterized in that: The two ends of the spiral pressure-equalizing groove (13) are respectively connected to the first annular pressure-equalizing groove (11) and the second annular pressure-equalizing groove (12).

7. The servo piston according to claim 2, characterized in that The width of the first annular pressure-equalizing groove (11), the width of the second annular pressure-equalizing groove (12), and the width of the spiral pressure-equalizing groove (13) are equal.

8. A servo variable mechanism, comprising a housing (100), wherein the housing (100) is provided with an oil hole, wherein: It also includes a sliding shoe (2) and a servo piston as described in any one of claims 1 to 7, the piston body (1) cooperates with the inner wall of the housing (100), the intermediate oil channel (15) is connected to the oil hole, the sliding shoe (2) includes a ball head, the piston body (1) is provided with a receiving groove that cooperates with the ball head, and the receiving groove is connected to the intermediate oil channel (15).

9. The servo variable mechanism according to claim 8, characterized in that: The intermediate oil passage (15) is arranged as a step-shaped structure, and the small end of the intermediate oil passage (15) is communicated with the containing groove.

10. A hydraulic motor comprising a swash plate (200), characterized in that: It also comprises the servo variable mechanism according to any one of claims 8 to 9, wherein the sliding shoe (2) abuts against the swash plate (200), and the sliding shoe (2) is used to change the angle of the swash plate (200).

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