Control valve

Abstract

The utility model provides a control valve. The control valve comprises a rotating shaft, a moving part, a centering spring, a middle position switch and a triggering mechanism. Torque is applied to the rotating shaft to rotate away from the neutral position. Rotation of the rotating shaft away from the neutral position causes the moving member to move in a first direction. The return spring urges the moving member in a second direction opposite to the first direction to maintain the rotating shaft to which no torque is applied in a neutral position. The neutral position switch is triggered to output a signal indicating that the rotating shaft leaves the neutral position. The triggering mechanism is located between the moving piece and the middle-position switch and transmits pressure to the pressure bearing part of the middle-position switch under pushing of the moving piece moving in the first direction so as to trigger the middle-position switch. The triggering mechanism comprises a transmission spring, pressure is transmitted to the pressure bearing part through the transmission spring, and the transmission spring is at least partially located in the inner space of the centering spring, so that the transmission spring and the centering spring integrally occupy small space in the length direction of the transmission spring and the centering spring, and the size of the control valve in the length direction is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of fluid control, and in particular, to a control valve for adjusting the displacement of an axial piston pump. Background Art

[0002] A pump is a device that can convert mechanical energy into the pressure energy of a liquid. As a type of pump, an axial piston pump changes the volume of hydraulic oil through the reciprocating motion of the piston in the cylinder, thereby achieving the suction and discharge of liquid. The displacement of some axial piston pumps is adjustable, and they can be called variable displacement axial piston pumps.

[0003] In hydraulic systems, axial piston pumps are often used in conjunction with displacement control valves (hereinafter referred to as control valves). By applying torque mechanically or manually, the shaft of the control valve will rotate away from the neutral position, thereby opening the control oil circuit, pushing the displacement adjustment member (e.g., swash plate) of the axial piston pump, and changing the displacement.

[0004] Control valves with a neutral position switch (NSS switch) are known. When the shaft leaves the neutral position, the neutral position switch is triggered and outputs a signal indicating that the shaft has left the neutral position, i.e., the displacement of the reactive axial piston pump is about to change. The control device can coordinate the hydraulic system accordingly.

[0005] However, the structure of the conventional control valve provided with a neutral switch is not compact enough. Utility Model Content

[0006] In view of this, the present disclosure provides a control valve with a mid-position switch, aiming to solve the problem of a compact structure.

[0007] The present disclosure provides a control valve including a rotating shaft, a moving member, a return spring, a neutral switch and a trigger mechanism. The rotating shaft is applied with a torque and rotates away from the neutral position. The rotation of the rotating shaft away from the neutral position causes the moving member to move in a first direction. The return spring presses the moving member in a second direction opposite to the first direction to keep the rotating shaft to which the torque is not applied in the neutral position. The neutral switch is triggered to output a signal indicating that the rotating shaft leaves the neutral position. The trigger mechanism is located between the moving member and the neutral switch, and under the push of the moving member moving in the first direction, the pressure is transmitted to the pressure-bearing part of the neutral switch to trigger the neutral switch. The trigger mechanism includes a transfer spring. The pressure is transmitted to the pressure-bearing part via the transfer spring. The transfer spring is at least partially located in the internal space of the return spring.

[0008] Since the transfer spring is at least partially located in the internal space of the return spring, the transfer spring and the return spring as a whole will occupy less space in the length direction of the two, which helps to reduce the size of the control valve in this length direction, thereby helping the control valve to obtain a more compact structure.

[0009] In a possible implementation, the rotating shaft is provided with a cutout portion, and the moving member includes a protruding portion. The action surface of the cutout portion includes: a rectangular plane facing the protruding portion and two flat side surfaces located on both sides of the rectangular plane and perpendicular to the rectangular plane, and the rectangular plane and the flat side surfaces are smoothly transitioned. The end surface of the protruding portion includes: two end planes and a central surface that is concave relative to the two end planes, and the protruding portion extends into the cutout portion and abuts against the action surface.

[0010] When the rotating shaft is not applied with torque, the moving part is applied with a left force by the return spring, so that the two end planes of the protrusion fit the rectangular plane on the rotating shaft, and the rotating shaft is kept in a neutral position. When the rotating shaft is applied with torque to leave the neutral position, the smooth transition corner between the rectangular plane and the flat side surface pushes the moving part, and the corner slides on the plane of the protrusion. During the rotation process of the rotating shaft, the active surface of the cutout portion will not contact the central surface of the protrusion. The purpose of providing the concave central surface is to avoid the wear of the two end planes after long-term use, resulting in the central part being relatively convex, which affects the accuracy of the return.

[0011] In a possible implementation manner, the control valve further includes a guide sleeve, the return spring surrounds at least a portion of the guide sleeve, and the guide sleeve surrounds at least a portion of the transfer spring.

[0012] On the one hand, the guide sleeve can guide the return spring and the transfer spring during their deformation process to prevent them from accidentally leaving the expected position. On the other hand, the guide sleeve can separate the return spring and the transfer spring so that the return spring and the transfer spring can be independent of each other during extension and compression without interference.

[0013] In a possible implementation, the moving member is provided with a receiving hole open to the first direction, the first end of the return spring extends into the receiving hole, and the guide sleeve partially extends into the receiving hole.

[0014] Since the guide sleeve partially extends into the receiving hole, the movable member and the guide sleeve as a whole will occupy less space in their length direction, which helps to reduce the size of the control valve in the length direction, thereby helping the control valve to obtain a more compact structure.

[0015] In one possible implementation, the guide sleeve includes a small diameter portion and a large diameter portion, and at least a portion of the return spring surrounds the small diameter portion and abuts against a step surface of the guide sleeve located between the small diameter portion and the large diameter portion to press the end surface of the large diameter portion against the non-pressure-bearing portion of the neutral switch.

[0016] When the rotating shaft leaves the neutral position, the moving member moves in the first direction, the distance between the abutting surface of the moving member and the step surface of the guide sleeve decreases, and the return spring is compressed. After the torque applied to the rotating shaft disappears, the moving member moves in the second direction under the elastic restoring force of the spring, the distance between the abutting surface of the moving member and the step surface of the guide sleeve decreases and increases, and the rotating shaft is restored to the neutral position.

[0017] In a possible implementation, a small diameter hole is provided in the small diameter portion, a large diameter hole is provided in the large diameter portion, the transfer spring is at least partially provided in the small diameter hole, and the pressure-bearing portion protrudes into the large diameter hole.

[0018] The transmission spring is arranged in the small diameter hole, has a relatively small diameter, and thus has a relatively small elastic force, which helps to prevent the trigger mechanism from causing overpressure on the neutral switch. The pressure-bearing part is arranged in the large diameter hole, which can prevent the guide sleeve from contacting the pressure-bearing part.

[0019] In a possible implementation, the trigger mechanism further includes a push rod, which is located between the moving member and the transfer spring and partially extends into the guide sleeve.

[0020] When the moving member moves in the first direction, the push rod will move in the first direction under the push of the moving member, pressing the transfer spring, and the transfer spring is compressed and transfers the pressure to the pressure-bearing part of the neutral switch to trigger the neutral switch.

[0021] In a possible implementation, the control valve further includes a sealing member, the guide sleeve is provided with a shoulder protruding inward from its inner wall, the push rod passes through the shoulder, and the sealing member is sleeved on the push rod and located in the guide sleeve on the side of the shoulder facing the moving member.

[0022] On the one hand, the cooperation between the shoulder and the ejector pin has a guiding and limiting effect, so that the ejector pin is guided and limited by the shoulder when moving, ensuring that it moves along the desired path and transmits the pressure to the transmission spring. On the other hand, the shoulder can also provide support and limit for the seal.

[0023] In a possible implementation, an inwardly protruding retracted portion is provided at the end of the guide sleeve close to the moving member, and the sealing member is located between the retracted portion and the shoulder.

[0024] During assembly, the seal can be installed into the guide sleeve from the end of the guide sleeve close to the moving member, over the retracted portion. After assembly, the seal will be limited in the first direction and the second direction between the retracted portion and the shoulder to keep the seal in the expected position and ensure the sealing effect.

[0025] In a possible implementation, the moving member is provided with a positioning recess, and the positioning recess receives an end of the push rod facing away from the transfer spring.

[0026] By cooperating with the positioning recess and the shoulder, the extension direction of the push rod can be consistent with the moving direction of the moving part, ensuring that it moves along the desired path and transmits the pressure to the transfer spring.

[0027] In a possible implementation, the trigger mechanism also includes a push rod, at least one first gasket and at least one second gasket, and the movement of the moving part is transmitted to the pressure-bearing part of the neutral switch via the push rod, at least one first gasket, a transfer spring, and at least one second gasket in sequence.

[0028] Since the gasket provides a larger contact surface, it can ensure uniform transmission and distribution of force. At the same time, the gap between components can be easily adjusted, which is beneficial to the coordination between components during the installation process.

[0029] In a possible implementation, the control valve further includes a valve core and a lever, and the rotation of the rotating shaft causes the valve core to slide through the lever, so as to adjust the displacement of the axial piston pump by controlling the fluid medium flowing through the control valve.

[0030] Due to the existence of the lever, the rotation of the shaft will cause the valve core to slide, thereby controlling the fluid medium flowing through the control valve and adjusting the displacement of the axial piston pump. This structure has the advantage of simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below.

[0032] It should be appreciated that the drawings depict only certain embodiments of the disclosure and are not to be considered limiting of the scope.

[0033] It should also be understood that the same or similar reference numerals are used in the drawings to represent the same or similar elements.

[0034] It should also be understood that the drawings are merely schematic and that the sizes and proportions of elements in the drawings are not necessarily accurate.

[0035] Figure 1 It is a schematic diagram of the structure of a control valve provided according to the present disclosure.

[0036] Figure 2 For along Figure 1 Schematic cross-sectional view taken along line AA.

[0037] Figure 3 for Figure 1 Exploded diagram of the control valve in FIG.

[0038] Figure 4 for Figure 2 A partial enlarged schematic diagram of part B.

[0039] Figure 5 for Figure 3 Schematic diagram of the structure of a part of the transfer shaft.

[0040] Figure 6 for Figure 3 Schematic diagram of the structure of the moving parts. DETAILED DESCRIPTION

[0041] Many specific details are listed herein to provide a deep understanding of the overall structure, function, and use of the embodiments described in the specification and shown in the drawings. Well-known operations, parts, and elements are not described in detail to avoid making the description in the specification too redundant. The reader will understand that the embodiments described and shown herein are non-limiting examples, so that it can be recognized that the specific structural and functional details mentioned herein may be representative and illustrative. These embodiments may be modified and changed without departing from the scope of the claims.

[0042] An axial piston pump is a device that can convert mechanical energy into the pressure energy of a liquid. An axial piston pump with adjustable displacement, also known as a variable displacement piston pump, generally includes a cylinder, a plunger, a swash plate, an oil distribution plate, and a drive shaft. The cylinder includes a plurality of plunger holes, so that the plunger can reciprocate in the plunger hole. The swash plate contacts the end of the plunger to control the reciprocating motion of the plunger. The oil distribution plate is located at one end of the cylinder and has an oil suction port and an oil discharge port to distribute the in and out of the hydraulic oil. The drive shaft drives the cylinder and the plunger to rotate. The volume of the hydraulic oil is changed by the reciprocating motion of the plunger in the cylinder, thereby realizing the suction and discharge of the liquid. In practical applications, it is often necessary to adjust the displacement of the axial piston pump to meet the needs of different working conditions. For this reason, the axial piston pump is often used in conjunction with a control valve.

[0043] The present disclosure provides a control valve 100, which can be used in conjunction with an axial piston pump to adjust the displacement of the axial piston pump. For ease of understanding, the overall structure of the control valve 100 is first illustrated below. It should be noted that the structure of the control valve 100 should not be limited to the description here. For example, in the absence of contradictions, one or several elements introduced below can be omitted or replaced, and the layout relationship between multiple elements can be replaced.

[0044] refer to Figure 1 and Figure 2 The control valve 100 may include a housing 10, a valve core 20, a rotating shaft 30 and a lever 40. The housing 10 can mount the control valve 100 on the axial piston pump. The lever 40 is connected to the rotating shaft 30 and the valve core 20. The lever 40 can rotate with the rotating shaft 30 to cause the valve core 20 to slide, thereby controlling the closing and conduction of the oil circuit, thereby controlling the fluid medium flowing through the control valve and adjusting the displacement of the axial piston pump.

[0045] refer to Figure 1 The control valve 100 may further include a handle 41, which is connected to the rotating shaft 30 and is located outside the housing 10. Thus, the operator can manually apply the torque. Of course, in other examples, the torque may be applied to the rotating shaft 30 by other structures, for example, by a motor.

[0046] refer to Figure 3 and Figure 4 The control valve 100 may further include a moving member 70. The moving member 70 abuts against the rotating shaft 30 through a cam, and when the rotating shaft 30 is applied with a torque and rotates away from the neutral position, the moving member 70 moves in the first direction.

[0047] Continue to refer Figure 3 and Figure 4 The control valve 100 may further include a return spring 50. When the rotating shaft 30 leaves the neutral position, the return spring 50 is compressed. After the torque applied to the rotating shaft 30 disappears, the rotating shaft 30 can be restored to the neutral position under the elastic restoring force of the spring.

[0048] Continue to refer Figure 3 and Figure 4 The control valve 100 may further include a neutral switch 60 (NSS switch). When the shaft 30 leaves the neutral position, the neutral switch 60 is triggered to output a signal, indicating that the shaft 30 leaves the neutral position, that is, the displacement of the reaction axial piston pump is about to change. The control device can coordinate the hydraulic system accordingly.

[0049] Continue to refer Figure 3 and Figure 4 , the control valve 100 may further include a trigger mechanism 80. The trigger mechanism 80 is located between the moving member 70 and the neutral switch 60, and under the push of the moving member 70 moving in the first direction, transmits pressure to the pressure-bearing portion 61 of the neutral switch 60 to trigger the neutral switch 60. As an example, the trigger mechanism 80 may include a transfer spring 81. The transfer spring 81 may be at least partially located in the internal space of the return spring 50, whereby the transfer spring 81 and the return spring 50 as a whole will occupy less space in the length direction of the two, which helps to reduce the size of the control valve 100 in the length direction, thereby helping the control valve 100 to obtain a more compact structure.

[0050] It should be noted that in the drawings of the present disclosure, the direction extending from X- to X+ is defined as the first direction, and the second direction is opposite to the first direction, and the direction extending from X+ to X- is defined as the second direction.

[0051] In order to enable the moving member 70 to move along the first direction as the rotating shaft 30 rotates, refer to Figures 3 to 6, the rotating shaft 30 may be provided with a cutout portion 31, and the moving member 70 may include a protrusion 71. The action surface of the cutout portion 31 includes: a rectangular plane 311 facing the protrusion 71 and two flat side surfaces 312 located on both sides of the rectangular plane 311 and perpendicular to the rectangular plane 311, and the rectangular plane 311 and the flat side surfaces 312 are smoothly transitioned. The end surface of the protrusion 71 includes: two end planes 711 and a central surface 712 recessed relative to the two end planes 711. The central surface 712 may be a plane or a curved surface. The protrusion 71 extends into the cutout portion 31 and abuts against the action surface. When the rotating shaft 30 is not applied with a torque, the moving member 70 is exerted with a leftward force by the return spring 50, so that the two end planes 711 of the protrusion 71 fit the rectangular plane 311 on the rotating shaft 30, and the rotating shaft 30 is kept in a neutral position. When the rotating shaft 30 is subjected to a torque to leave the neutral position, the smooth transition corner between the rectangular plane 31 and the flat side surface 312 pushes the moving member 70, and the corner slides on the plane 711 of the protrusion 71. The rotating shaft 30 is provided with a hole 32, and the ball 33 is installed on the hole 32. The sliding angle of the rotating shaft 30 is limited by the moving range of the ball 33 in the corresponding groove on the housing 10. During the rotation of the rotating shaft 30, the active surface of the cutout portion 31 will not contact the central surface 712 of the protrusion 71. The purpose of providing the concave central surface is to avoid the wear of the two end planes 711 after long-term use, resulting in the central part being relatively convex, which affects the accuracy of the return.

[0052] Since the transmission spring 81 of the trigger mechanism 80 is at least partially located in the inner space of the return spring 50, in order to better guide the two springs and avoid displacement or entanglement between the two springs, refer to Figure 4 The control valve 100 may further include a guide sleeve 90, the return spring 50 surrounds at least a portion of the guide sleeve 90, and the guide sleeve 90 surrounds at least a portion of the transfer spring 81. According to the above implementation, on the one hand, the guide sleeve 90 can guide the return spring 50 and the transfer spring 81 during their deformation process to prevent them from accidentally leaving the expected position. On the other hand, the guide sleeve 90 can separate the return spring 50 and the transfer spring 81, so that the return spring 50 and the transfer spring 81 can be independent of each other during extension and compression without interference.

[0053] Continue to refer Figure 4, the moving member 70 may be provided with a receiving hole 72 open to the first direction, and the inner end of the receiving hole 72 is provided with abutting surface 73. The guide sleeve 90 may include a small diameter portion 91 and a large diameter portion 92, the large diameter portion 92 is located at a section of the small diameter portion 91 away from the moving member 70, at least part of the return spring 50 surrounds the small diameter portion 91, one end of the return spring 50 extends into the receiving hole 72 and abuts against the abutting surface 73 of the moving member 70, and the other end of the return spring 50 abuts against the step surface 93 of the guide sleeve 90 located between the small diameter portion 91 and the large diameter portion 92, so as to press the end surface of the large diameter portion 92 against the non-pressure-bearing portion of the neutral switch 60. In the process of the rotating shaft 30 leaving the neutral position, the moving member 70 moves in the first direction, the distance between the abutting surface 73 of the moving member 70 and the step surface 93 of the guide sleeve 90 is reduced, and the return spring 50 is compressed. After the torque applied to the rotating shaft 30 disappears, under the elastic restoring force of the spring, the movable member 70 moves in the second direction, the distance between the abutment surface 73 of the movable member 70 and the step surface 93 of the guide sleeve 90 decreases and increases, and the rotating shaft 30 is restored to the neutral position.

[0054] It can be understood that in the above embodiment, due to the presence of the large diameter portion 92, one end of the return spring 50 can abut against the step surface 93 between the large diameter portion 92 and the small diameter hole 911. However, in some other embodiments, the outer diameter of the guide sleeve 90 can remain consistent, that is, the transfer spring 81 no longer relies on the guide sleeve 90 to provide the step surface 93. At this time, the transfer spring 81 can abut against the abutment surface 73 of the receiving hole 72 of the moving member 70 at one end, and the other end abuts against the portion of the neutral switch 60 other than the pressure-bearing portion.

[0055] refer to Figure 2 and Figure 4 , the guide sleeve 90 can be partially extended into the receiving hole 72. Since the guide sleeve 90 partially extends into the receiving hole 72, the space occupied by the moving member 70 and the guide sleeve 90 as a whole in the length direction of the two will be smaller, which helps to reduce the size of the control valve 100 in the length direction, thereby helping the control valve 100 to obtain a more compact structure. In addition, since the guide sleeve 90 partially extends into the receiving hole 72, any part of the return spring 50 will be guided by at least one of the moving member 70 and the guide sleeve 90.

[0056] In order to enable the guide sleeve 90 to surround at least a portion of the transfer spring 81, a hole may be provided in the guide sleeve 90. Figure 4A small diameter hole 911 may be provided in the small diameter portion 91, a large diameter hole 921 may be provided in the large diameter portion 92, the transmission spring 81 is at least partially provided in the small diameter hole 911, and the pressure-bearing portion 61 protrudes into the large diameter hole 921. The transmission spring 81 is provided in the small diameter hole 911 and has a relatively small diameter, thereby having a relatively small elastic force, which helps to prevent the trigger mechanism 80 from causing overpressure on the middle switch 60. The pressure-bearing portion 61 is provided in the large diameter hole 921, which can prevent the guide sleeve 90 from contacting the pressure-bearing portion 61.

[0057] In the process of the moving member 70 transmitting pressure to the trigger mechanism 80, the transmission spring 81 may be in direct contact with the moving member 70, or other components may be arranged on the transmission path. Figure 4 The trigger mechanism 80 may include a push rod 82. The push rod 82 is located between the moving member 70 and the transfer spring 81, and partially extends into the guide sleeve 90. When the moving member 70 moves in the first direction, the push rod 82 will move in the first direction under the push of the moving member 70, pressing the transfer spring 81, and the transfer spring 81 is compressed and transfers the pressure to the pressure-bearing portion 61 of the middle switch 60 to trigger the middle switch 60.

[0058] It can be understood that in order to better transmit the pressure from the moving part 70, the axis of the push rod 82 can coincide with the axis of the protrusion 71 to avoid the push rod 82 from being offset during the pressure transmission process, thereby affecting the pressure transmitted to the pressure-bearing part 61 and failing to trigger the neutral switch 60.

[0059] Furthermore, a sealing member 96 may be provided between the trigger mechanism 80 and the moving member 70 . The sealing member 96 is sleeved on the ejector rod 82 and located in the guide sleeve 90 to provide a seal between the outer surface of the ejector rod 82 and the inner wall of the guide sleeve 90 .

[0060] refer to Figure 4 The guide sleeve 90 may be provided with a shoulder 94 protruding inward from its inner wall, the ejector rod 82 partially extends into the guide sleeve 90, and extends from the first side of the shoulder 94 through the shoulder 94 to the second side of the shoulder 94 along the first direction, and the seal 96 is sleeved on the ejector rod 82 and located on the first side of the shoulder 94. On the one hand, the cooperation between the shoulder 94 and the ejector rod 82 has a guiding and limiting function, so that the ejector rod 82 is guided and limited by the shoulder 94 when moving, ensuring that it moves along the desired path and transmits the pressure to the transmission spring 81. On the other hand, the shoulder 94 can also provide support and limit for the seal 96.

[0061] Continue to refer Figure 4The end of the guide sleeve 90 close to the moving member 70 is provided with an inwardly protruding retracted portion 95, and the sealing member 96 is located between the retracted portion 95 and the shoulder 94. During assembly, the sealing member 96 can be installed into the guide sleeve 90 from the end of the guide sleeve 90 close to the moving member 70, over the retracted portion 95. After the assembly is completed, the sealing member 96 will be limited in the first direction and the second direction between the retracted portion 95 and the shoulder 94 to keep the sealing member 96 in the expected position to ensure the sealing effect.

[0062] Continue to refer Figure 4 The abutting surface 73 of the moving member 70 may be provided with a positioning recess 731, which receives the end of the push rod 82 away from the transfer spring 81. Through the cooperation with the positioning recess 731 and the shoulder 94, the extension direction of the push rod 82 can be consistent with the moving direction of the moving member 70, ensuring that it moves along the desired path and transmits the pressure to the transfer spring 81.

[0063] It can be understood that the present disclosure does not impose any particular limitation on the shape of the positioning recess 731, as long as it is compatible with the shape of the end of the push rod 82. As an example, the end of the push rod 82 may be hemispherical, and accordingly, the positioning recess 731 is a hemispherical recess. As another example, when the end of the push rod 82 may be a cube, accordingly, the positioning recess 731 is a cube recess.

[0064] Continue to refer Figure 4 , the trigger mechanism 80 may also include at least one first gasket 83 and at least one second gasket 84. One end of the push rod 82 abuts against the moving member 70 and the other end abuts against at least one first gasket 83, one end of the transfer spring 81 abuts against at least one first gasket 83 and the other end abuts against at least one second gasket 84, and the second gasket 84 presses against the pressure-bearing portion 61, so that the movement of the moving member 70 is transmitted to the pressure-bearing portion 61 of the neutral switch 60 via the push rod 82, at least one first gasket 83, the transfer spring 81, and at least one second gasket 84 in sequence. Since the gasket provides a larger contact surface, it is possible to ensure uniform transmission and distribution of force. In addition, by using gaskets, the gaps between components can be easily adjusted, which is beneficial to the coordination between the components during the installation process.

[0065] It should be understood that the term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "according to" means "at least in part according to". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least another embodiment".

[0066] It should be understood that although the terms "first" or "second" etc. may be used in the present invention to describe various elements (such as a first gasket and a second gasket), these elements are not defined by these terms, and these terms are only used to distinguish one element from another.

[0067] The protection scope of the present invention is not limited to the above-mentioned embodiments. Any changes or substitutions that can be conceived by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A control valve for adjusting the displacement of an axial piston pump, characterized in that: include: A shaft, which is rotated away from a neutral position by an applied torque; a moving member, wherein rotation of the rotating shaft away from the neutral position causes the moving member to move in a first direction; a return spring, urging the moving member in a second direction opposite to the first direction, so as to keep the rotating shaft to which no torque is applied in the neutral position; a neutral switch, which is triggered to output a signal indicating that the rotating shaft leaves the neutral position; as well as A trigger mechanism is located between the moving member and the neutral switch, and under the push of the moving member moving in the first direction, transmits pressure to the pressure-bearing part of the neutral switch to trigger the neutral switch, wherein the trigger mechanism includes a transfer spring, and the pressure is transmitted to the pressure-bearing part via the transfer spring, and the transfer spring is at least partially located in the internal space of the return-to-center spring.

2. The control valve according to claim 1, characterized in that: The rotating shaft is provided with a cut-out portion, and the movable part includes a protruding portion. The active surface of the cut-out portion includes: a rectangular plane facing the protruding portion and two flat side surfaces located on both sides of the rectangular plane and perpendicular to the rectangular plane, and the rectangular plane and the flat side surfaces have a smooth transition; the end surface of the protruding portion includes: two end planes and a central surface recessed relative to the two end planes, and the protruding portion extends into the cut-out portion and abuts against the active surface.

3. The control valve according to claim 1, characterized in that: A guide sleeve is also included, the centering spring surrounds at least a portion of the guide sleeve, and the guide sleeve surrounds at least a portion of the transfer spring.

4. The control valve according to claim 3, characterized in that: The moving member is provided with a receiving hole which is open to the first direction, one end of the centering spring extends into the receiving hole, and the guide sleeve partially extends into the receiving hole.

5. The control valve according to claim 3, characterized in that: The guide sleeve includes a small diameter portion and a large diameter portion, and at least part of the return spring surrounds the small diameter portion and abuts against a step surface of the guide sleeve located between the small diameter portion and the large diameter portion to press the end surface of the large diameter portion against the non-pressure-bearing portion of the neutral switch.

6. The control valve according to claim 5, characterized in that A small-diameter hole is provided in the small-diameter portion, a large-diameter hole is provided in the large-diameter portion, the transmission spring is at least partially provided in the small-diameter hole, and the pressure-bearing portion protrudes into the large-diameter hole.

7. The control valve according to claim 3, characterized in that: The trigger mechanism further comprises a push rod, which is located between the moving member and the transfer spring and partially extends into the guide sleeve.

8. The control valve according to claim 7, characterized in that: The control valve also includes a sealing member. The guide sleeve is provided with a shoulder protruding inward from its inner wall. The push rod passes through the shoulder. On the side of the shoulder facing the moving member, the sealing member is sleeved on the push rod and located in the guide sleeve.

9. The control valve according to claim 8, characterized in that The end of the guide sleeve close to the moving member is provided with an inwardly protruding retracted portion, and the sealing member is located between the retracted portion and the shoulder.

10. The control valve according to claim 8, characterized in that The moving member is provided with a positioning recess, and the positioning recess receives an end of the push rod away from the transfer spring.

11. The control valve according to claim 1, characterized in that The trigger mechanism also includes a push rod, at least one first gasket and at least one second gasket. The movement of the moving member is sequentially transmitted to the pressure-bearing part of the neutral switch via the push rod, the at least one first gasket, the transfer spring and at least one second gasket.

12. The control valve according to any one of claims 1 to 11, characterized in that: It also includes a valve core and a shift rod. The rotation of the rotating shaft causes the valve core to slide through the shift rod, so as to adjust the displacement of the axial piston pump by controlling the fluid medium flowing through the control valve.

Images