Swash plate type variable displacement plunger pump or swash plate type variable displacement plunger motor

Abstract

The utility model provides a swash plate type variable displacement plunger pump or a swash plate type variable displacement plunger motor. The swash plate type variable displacement plunger pump or the swash plate type variable displacement plunger motor comprises a shell; the swash plate is arranged in the shell; the servo mechanism comprises a servo oil cylinder and a servo piston, the servo oil cylinder is arranged on the shell, the servo piston partially extends into the servo oil cylinder, and the servo piston is connected to the swash plate, so that the preset position of the swash plate can be arranged by adjusting the servo oil cylinder; and the positioning structure comprises a positioning piece extending from the outer side of the shell and a positioning concave part pressed out by the positioning piece on the servo oil cylinder, and the positioning piece is inserted into the positioning concave part to prevent the servo oil cylinder from rotating. In this way, the servo oil cylinder can be adjusted to the middle position through the positioning structure, the structure is simple, operation is convenient, and cost saving is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of hydraulic transmission, and in particular to a swash plate type variable displacement plunger pump or a swash plate type variable displacement plunger motor. Background Art

[0002] In hydraulic transmission and control technology, swash plate variable displacement piston pumps and motors are two important hydraulic components, widely used in engineering machinery, agricultural machinery, ships, aircraft, industrial automation and other fields. They achieve continuous adjustment of displacement by changing the inclination angle of the swash plate, thereby meeting the different flow and pressure requirements of the system.

[0003] In order to prevent the center position of the swash plate from being unexpectedly offset due to external force, a common practice is to set a circumferential limit structure between the servo cylinder and the housing to limit the rotation of the servo cylinder relative to the housing under the action of external force. However, the circumferential limit structure in the prior art is complicated to install, and the product processing technology is complicated and the cost is high. Utility Model Content

[0004] In view of this, the present application provides a swash plate type variable displacement piston pump or a swash plate type variable displacement piston motor, which has a simple structure, is easy to operate, and saves costs.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] A swash plate type variable displacement plunger pump or a swash plate type variable displacement plunger motor, comprising:

[0007] case;

[0008] a swash plate disposed in the housing;

[0009] a servo mechanism, the servo mechanism comprising a servo cylinder disposed on the housing and a servo piston partially extending into the servo cylinder, the servo piston being connected to the swash plate so that a predetermined position of the swash plate can be set by adjusting the servo cylinder; and

[0010] The positioning structure comprises: a positioning piece extending from the outer side of the housing, and a positioning recess pressed out by the positioning piece on the servo oil cylinder, wherein the positioning piece is inserted into the positioning recess to prevent the servo oil cylinder from rotating.

[0011] Optionally, the servo cylinder is threadedly connected to the housing, and after the servo cylinder is screwed to set the middle position of the swash plate, the positioning member presses out of the positioning recess.

[0012] Optionally, the positioning member is threadedly connected to the positioning hole on the housing, and the positioning recess is pressed out on the outer peripheral surface of the servo cylinder by screwing the positioning member.

[0013] Optionally, the material hardness of the positioning member is greater than the material hardness of the servo cylinder.

[0014] Optionally, one end of the positioning member is configured as a tip portion that can extend into the positioning recess, and the other end is configured as an operating portion that can be screwed by a tool.

[0015] Optionally, the positioning member is configured as a set screw.

[0016] Optionally, an extension direction of the positioning hole is perpendicular to the axial direction of the servo cylinder.

[0017] Optionally, the aperture of the positioning hole is set to 4-12 mm.

[0018] Optionally, the depth of the positioning recess is set to 0.3-0.5 mm.

[0019] Optionally, the positioning member is connected to a positioning hole on the shell through a connecting member, and when the connecting member is connected to the shell, the positioning member can be limited in the positioning hole and the positioning recess.

[0020] The swash plate type variable displacement piston pump or swash plate type variable displacement piston motor provided by the present application, when the original servo cylinder needs to be reinstalled after being removed, the position of the positioning recess is observed through the positioning hole while rotating the servo cylinder until the positioning hole and the positioning recess are aligned and then the rotation of the servo cylinder is stopped. At this time, the servo cylinder and the swash plate are in the middle position. When the servo cylinder is in the middle position, the positioning member extends from the outside of the housing into the positioning hole and is inserted into the positioning recess, thereby limiting the rotation of the servo cylinder relative to the housing and locking the middle position of the servo cylinder and the swash plate. In this way, the servo cylinder can be adjusted to the middle position through the positioning structure, the structure is simple, and it is convenient for on-site installation without a test bench or tooling, which is conducive to cost saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0022] Figure 1 A cross-sectional view of a swash plate type variable displacement piston pump or a swash plate type variable displacement piston motor according to some embodiments;

[0023] Figure 2 A perspective view of a swash plate type variable displacement piston pump or a swash plate type variable displacement piston motor according to some embodiments;

[0024] Figure 3 The exploded perspective view of the servo cylinder and the positioning member shown in some embodiments;

[0025] Figure 4 Detailed cross-sectional views of the servo cylinder and the positioning member shown in some embodiments;

[0026] Figure 5 A cross-sectional view of a positioning member shown in some embodiments;

[0027] Figure 6 A partial cross-sectional schematic diagram of a swash plate type variable displacement piston pump or a swash plate type variable displacement piston motor according to some embodiments;

[0028] Figure 7 It is a partial cross-sectional schematic diagram of a swash plate type variable displacement piston pump or a swash plate type variable displacement piston motor showing other embodiments.

[0029] In the figure: 1, housing; 2, servo cylinder; 3, servo piston; 4, spring base; 5, swash plate; 6, positioning hole; 7, positioning piece; 8, positioning recess; 9, connecting piece; 71, tip; 72, threaded portion; 73, operating portion. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] like Figure 1-Figure 7 As shown, an embodiment of the present application provides a swash plate type variable displacement piston pump or a swash plate type variable displacement piston motor, including a housing 1, a swash plate 5, a servo mechanism and a positioning structure.

[0032] The servo mechanism includes a servo cylinder 2 and a servo piston 3. Two servo cylinders 2 are provided. The two servo cylinders 2 are located on opposite sides of the housing 1 and are connected to the housing 1 through a threaded structure. In the assembled state, the servo cylinder 2 extends into the interior of the housing 1. In addition, a cylinder hole is provided on the side of the servo cylinder 2 facing the inner cavity of the housing 1. The servo piston 3 includes a piston rod and two piston heads respectively located at both ends of the piston rod, wherein the two piston heads respectively extend into the cylinder holes of the two servo cylinders 2 and can reciprocate in the cylinder holes along the axial direction of the servo cylinder 2. A spring is provided between the piston heads, and the spring is pressed between the two piston heads through a spring base 4. When the swash plate is in the middle position on the test bench or during the installation process, the servo cylinder is screwed to a position where its end face fits the spring base 4. If a slight deviation is found in the middle position of the swash plate, it can be adjusted by screwing the servo cylinder 2.

[0033] Specifically, Figure 1 Taking the case where the middle swash plate 5 needs to be adjusted to the left as an example, the centering process of the swash plate 5 is explained as follows: the servo cylinder 2 on the right side of the figure is screwed into the housing 1, and the servo cylinder 2 on the right side of the figure is used to push the corresponding spring base 4 to move to the left, thereby separating the spring base 4 from the piston head, thereby destroying the force balance of the servo piston 3, and causing the servo piston 3 to move to the left until the right piston head abuts against the spring base 4 again. As the servo piston 3 moves to the left, the left spring head will separate from the spring base 4 (because the spring base 4 is held in place by the servo cylinder 4). At this time, the servo cylinder 2 on the left side needs to be screwed to the left as well, so that the end face of the servo cylinder 2 moves to the left the same distance as the left piston head, until the end faces of the servo cylinders 2 on both sides are in contact with the spring base 4. Since the swash plate 5 is connected to the servo piston 3, the swash plate 5 will move to the left as the servo piston 3 moves to the left, and the centering adjustment of the swash plate 5 is achieved by adjusting the servo cylinder 2.

[0034] After adjusting the middle position of the swash plate 5, since the pre-tightening torque of the servo cylinder is only within the set range, this torque is only to resist the friction force when the sealing ring is screwed in and the friction force of the thread pair, which is very small compared to the conventional thread pre-tightening torque, so it can be considered that the thread of the servo cylinder is in an unpre-tightened state, and additional thread anti-loosening means are required to ensure that the servo cylinder does not screw out of the hole when the pump is working. If the servo oil cylinder 2 rotates relative to the housing 1, it will directly affect the position of the swash plate 5, making it unable to maintain the middle position, resulting in output flow / outlet pressure difference when the pump motor is in the "middle position", causing the actuator (if the hydraulic device is a pump, the actuator can be a motor or oil cylinder; if the hydraulic device is a motor, the actuator can be an external actuator) to malfunction, unable to fully realize the stop function or cause a safety accident. Based on this, in the embodiment of the present application, a positioning structure is provided between the servo cylinder 2 and the housing 1, and the positioning structure includes a positioning member 7 and a positioning recess 8. A positioning hole 6 is provided on the housing 1, and the positioning member 7 is inserted into the positioning hole 6 and connected to the housing 1, and the positioning recess 8 is provided on the outer peripheral surface of the servo cylinder 2. When the servo cylinder 2 needs to be adjusted to the middle position, while rotating the servo cylinder 2, the position of the positioning recess 8 is observed through the positioning hole 6, until the positions of the positioning hole 6 and the positioning recess 8 are aligned, and then the rotation of the servo cylinder 2 is stopped. At this time, the servo cylinder 2 and the swash plate 5 are in the middle position. When the servo cylinder 2 is in the middle position, the positioning member 7 extends from the outside of the housing 1 into the positioning hole 6 and is inserted into the positioning recess 8, thereby limiting the rotation of the servo cylinder 2 relative to the housing 1, and locking the middle position of the servo cylinder 2 and the swash plate 5. In this way, the servo cylinder 2 can be adjusted to the middle position through the positioning structure, which has a simple structure, is easy to operate, and is conducive to cost saving.

[0035] It should be noted that the positioning recess 8 can be formed integrally with the servo cylinder 2, or can be a structure that is separately processed on the formed servo cylinder 2. Here, preferably, the positioning recess 8 is set as a pit pressed out by the positioning member 7 on the servo cylinder 2 during initial assembly. The depth of the positioning recess 8 is set to 0.1-1 mm, preferably 0.3-0.5 mm.

[0036] like Figure 5As shown, the positioning member 7 includes a tip 71, a threaded portion 72 and an operating portion 73 in the axial direction, and the tip 71 and the operating portion 73 are respectively arranged at the two ends of the threaded portion 72. Among them, the cross-sectional area of ​​the tip 71 gradually decreases in the direction away from the operating portion 73. For example, the shape of the tip 71 is set to a hemispherical, truncated cone, conical or other structure, and the material hardness of the tip 71 is greater than the material hardness of the servo cylinder 2. For example, the servo cylinder 2 is set to QT-405 material (it can also be gray iron or steel material), and the tip 71 (i.e., the positioning member 7) is set to a steel material with higher hardness or other hard materials. The operating portion 73 can be screwed by a tool. For example, the end surface of the threaded portion 72 away from the tip 71 is provided with a groove (the shape of the groove can be set to be a straight or hexagonal shape) to form the above-mentioned operating portion 73. The positioning hole 6 on the housing 1 is set to a threaded hole and matches the threaded portion 72, so that the positioning member 7 can be screwed into the positioning hole 6. During the initial assembly and positioning, keep the servo cylinder 2 in the middle position, use a tool to screw the operating part 73, and then drive the entire positioning member 7 (the tip 71, the threaded part 72 and the operating part 73) to rotate in the positioning hole 6. Since the threaded part 72 and the positioning hole 6 are threadedly matched, the tip 71 can be close to and abut the outer peripheral surface of the servo cylinder 2; continue to screw the operating part 73, the tip 71 is gradually pressed into the surface of the servo cylinder 2, and a positioning recess 8 is pressed out on the outer peripheral surface of the servo cylinder 2. Later, during the maintenance process, the servo cylinder 2 can be adjusted to the middle position again through the pressed positioning recess 8.

[0037] The extending direction of the positioning hole 6 is perpendicular to the axial direction of the servo oil cylinder 2, so that the positioning member 7 can be gradually inserted into the positioning recess 8 along the radial direction of the servo oil cylinder 2, which can ensure the force balance of the servo oil cylinder 2. In addition, the outer diameter of the positioning member 7 is set to 4-12 mm, that is, the outer diameter of the positioning hole 6 is set to 4-12 mm, which can ensure both the connection strength of the positioning member 7 and the structural strength of the housing 1.

[0038] Based on the structure of the positioning member 7, as Figure 5 , 6 As shown, the positioning member 7 in this solution is preferably set as a set screw, and the selection of the set screw is M4-M12, and M6 is preferred here. Since the set screw is an existing component, no additional processing is required, so that in this design, only a threaded hole needs to be processed at a corresponding position on the housing 1 to cooperate with the set screw, which is simple in structure and conducive to cost saving.

[0039] In another scheme, if Figure 7As shown, the positioning structure may also include a connector 9. When positioning, the connector 9 is connected to the positioning hole 6 on the housing 1. For example, the connector 9 is connected to the positioning hole 6 by a threaded structure. At the same time, the connector 9 limits the positioning member 7 in the positioning hole 6 and the positioning recess 8. Since the positioning member 7 is located in both the housing 1 and the servo cylinder 2, the rotation of the servo cylinder 2 relative to the housing 1 can be limited. The difference between this solution and the above-mentioned set screw solution is that the set screw is an integrated structure, which can be connected to the positioning hole 6 on the housing 1 and can be inserted into the positioning recess 8 of the servo cylinder 2, and has both connection and positioning functions; while in this solution, the connector 9 is only used to connect to the positioning hole 6 of the housing 1, and the positioning member 7 is only used to insert into the positioning hole 6 and the positioning recess 8. The connector 9 and the positioning member 7 have the two functions of connection and positioning, respectively.

[0040] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0041] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0042] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0043] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A swash plate type variable displacement piston pump or a swash plate type variable displacement piston motor, characterized in that: include: case; a swash plate disposed in the housing; A servo mechanism, the servo mechanism comprising a servo cylinder disposed on the housing and a servo piston partially extending into the servo cylinder, the servo piston being connected to the swash plate so that a predetermined position of the swash plate can be set by adjusting the servo cylinder; as well as The positioning structure comprises: a positioning piece extending from the outer side of the housing, and a positioning recess pressed out by the positioning piece on the servo oil cylinder, wherein the positioning piece is inserted into the positioning recess to prevent the servo oil cylinder from rotating.

2. The swash plate type variable displacement piston pump or swash plate type variable displacement piston motor according to claim 1, characterized in that: The servo oil cylinder is threadedly connected to the housing, and after the servo oil cylinder is screwed to set the middle position of the swash plate, the positioning member presses out of the positioning recess.

3. The swash plate type variable displacement piston pump or swash plate type variable displacement piston motor according to claim 1, characterized in that: The positioning piece is threadedly connected to the positioning hole on the housing, and the positioning recess is pressed out on the outer peripheral surface of the servo oil cylinder by screwing the positioning piece.

4. The swash plate type variable displacement piston pump or swash plate type variable displacement piston motor according to claim 3, characterized in that: The material hardness of the positioning member is greater than the material hardness of the servo cylinder.

5. The swash plate type variable displacement piston pump or swash plate type variable displacement piston motor according to claim 3, characterized in that: One end of the positioning member is configured as a tip portion that can extend into the positioning recess, and the other end is configured as an operating portion that can be screwed by a tool.

6. The swash plate type variable displacement piston pump or swash plate type variable displacement piston motor according to claim 5, characterized in that: The positioning member is configured as a set screw.

7. The swash plate type variable displacement piston pump or swash plate type variable displacement piston motor according to claim 3, characterized in that: The extending direction of the positioning hole is perpendicular to the axial direction of the servo cylinder.

8. The swash plate type variable displacement piston pump or swash plate type variable displacement piston motor according to claim 6, characterized in that: The specification of the set screw is M4-M12.

9. The swash plate type variable displacement piston pump or swash plate type variable displacement piston motor according to claim 1, characterized in that: The depth of the positioning recess is set to 0.3-0.5 mm.

10. The swash plate type variable displacement piston pump or swash plate type variable displacement piston motor according to claim 1, characterized in that: The positioning member is connected to the positioning hole on the shell through a connecting member. When the connecting member is connected to the shell, the positioning member can be limited in the positioning hole and the positioning recess.

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