A skid steer loader lift and level valve

Abstract

The utility model discloses a kind of lifting leveling valves of skid loader, including valve body, core components such as shunt valve, one-way valve are integrally arranged in valve body, shunt valve displacement is limited by centering plug, avoid the abnormal reset force caused by the reset spring distortion of shunt valve, further prevent automatic outswing of dipper;With the help of one-way valve, the hydraulic oil flow path when boom is lowered is optimized, and pressure loss and abnormal sound are reduced.The utility model has reasonable structure design, can effectively improve the stability and reliability of skid loader working device, and is suitable for the hydraulic system of various skid loaders.

Description

Technical Field

[0001] This utility model relates to the hydraulic technology of skid steer loaders, and more specifically, to the structure of a lifting and leveling valve for a skid steer loader. Background Technology

[0002] During the operation of a skid steer loader, to prevent material from falling from the bucket or forks during boom lifting, a leveling valve is typically installed in the hydraulic system of the working device. This valve automatically levels the bucket or forks while maintaining a constant angle with the ground during boom lifting. However, existing leveling valves have certain drawbacks in practical use: Firstly, the return spring of the diverter valve lacks a stable guiding and limiting structure, making it prone to twisting during operation. This reduces or eliminates the return force, allowing hydraulic oil to easily enter the rodless chamber of the bucket cylinder through the diverter valve during boom descent, causing the bucket to automatically swing outward. Secondly, during boom descent, hydraulic oil must pass through the throttling plate of the diverter valve to enter the rod chamber of the boom cylinder, resulting in significant hydraulic oil pressure loss and abnormal noise. This affects the working stability and efficiency of the skid steer loader, causing inconvenience to users. Utility Model Content

[0003] To address the aforementioned problems in the existing technology, this utility model provides a skid steer loader lifting and leveling valve, which can solve the technical defects of existing leveling valves where the bucket automatically swings outward and there is loud noise during the lowering action when the boom overflows.

[0004] To achieve the above-mentioned objectives, the technical solution adopted by this utility model is as follows:

[0005] A skid steer loader lifting and leveling valve includes a valve body 26. The valve body 26 contains a diversion valve chamber 19, an oil inlet chamber 17, a first flow channel 22, a second flow channel 15, and a first one-way valve lower chamber 20. A diversion valve 18 is installed within the diversion valve chamber 19. One end of the diversion valve 18 abuts against a first return spring 24, and the end of the first return spring 24 away from the diversion valve 18 abuts against a centering plug 27. The centering plug 27 is fixedly installed at one end of the diversion valve chamber 19. The other end of the diversion valve 18 is opposite to a first plug 12, which is fixedly installed at the other end of the diversion valve chamber 19. The centering plug 27 and the first plug 12 form a support to the diversion valve 18 along the axial direction of the diversion valve chamber 19. The system provides bidirectional limiting; a first one-way valve 16 is installed between the lower chamber 20 of the first one-way valve and the oil inlet chamber 17. The valve core of the first one-way valve 16 is adapted to the flow channels of the lower chamber 20 of the first one-way valve and the oil inlet chamber 17, and is used to open and close the first flow channel 22 and the oil inlet chamber 17; the oil inlet chamber 17 forms two connecting paths with the second flow channel 15 and the first flow channel 22 respectively through the diversion valve chamber 19, namely the first connecting path of oil inlet chamber 17 → diversion valve chamber 19 → second flow channel 15, and the second connecting path of oil inlet chamber 17 → diversion valve chamber 19 → first flow channel 22; the valve port of the diversion valve 18 is adapted to the intersection of the two connecting paths, and the oil diversion is achieved by switching the on and off states of the two connecting paths through the diversion valve 18.

[0006] Furthermore, a first throttling vane 14 and a second throttling vane 21 are respectively embedded in the inner cavities of both ends of the diversion valve 18. A first retaining ring 13 and a second retaining ring 23 are respectively snapped into the two ends of the diversion valve 18. The first retaining ring 13 abuts against the side of the first throttling vane 14 away from the axis of the diversion valve 18, and the second retaining ring 23 abuts against the side of the second throttling vane 21 away from the axis of the diversion valve 18, so as to realize the axial fixation of the first throttling vane 14 and the second throttling vane 21 in the inner cavity of the diversion valve 18. By adjusting the area of ​​the two throttling vanes, the flow can be accurately diverted.

[0007] Furthermore, the valve body 26 is provided with a first working chamber 2, and a third flow channel is provided between the first working chamber 2 and the second flow channel 15. A second one-way valve 1 is installed in the third flow channel. The valve core of the second one-way valve 1 is adapted to the third flow channel to switch the first working chamber 2 and the second flow channel 15 on and off, so as to ensure the reliability of bucket leveling when the boom is lifted.

[0008] Furthermore, the valve body 26 is provided with a relief valve lower chamber 4, and a fourth flow channel is provided between the relief valve lower chamber 4 and the first flow channel 22. A relief valve 11 is installed in the fourth flow channel. The valve core of the relief valve 11 is adapted to the fourth flow channel to switch the second flow channel 15 and the first flow channel 22. The side of the valve core of the relief valve 11 facing the first flow channel 22 is the sealing surface to prevent hydraulic oil backflow and protect the hydraulic system components.

[0009] Furthermore, the valve body 26 is provided with a lower shut-off valve chamber 9 and a second working chamber 7. A fifth flow channel is provided between the lower shut-off valve chamber 9 and the second flow channel 15. A shut-off valve 3 is installed in the fifth flow channel. One end of the shut-off valve 3 abuts against a second return spring 8. The end of the second return spring 8 away from the shut-off valve 3 abuts against a third throttling plate 6. The third throttling plate 6 is fixedly installed in the fifth flow channel. The other end of the shut-off valve 3 is arranged opposite to the valve core of the second one-way valve 1. A second plug 10 is fixedly installed at the port of the fifth flow channel. The second plug 10 and the second one-way valve 1 are located on both sides of the shut-off valve 3, forming an axial limit on the shut-off valve 3. The valve body 26 is also provided with a shut-off valve feedback channel 5. One end of the shut-off valve feedback channel 5 is connected to the lower shut-off valve chamber 9, and the other end is connected to the first flow channel 22. The valve port of the shut-off valve 3 is adapted to the connecting flow channel between the lower shut-off valve chamber 9 and the second working chamber 7, and is used to switch the first flow channel 22 and the second working chamber 7 to achieve flexible switching of working state.

[0010] Furthermore, the diverter valve 18 and the valve body 26 are integrated into one structure. The centering plug 27 and the first plug 12 are both fixed to the two ends of the diverter valve cavity 19 by threaded connection. The axis of the centering plug 27 is collinear with the axis of the diverter valve cavity 19, and the axis of the first return spring 24 is collinear with the axis of the diverter valve 18, ensuring that the diverter valve 18 always moves along the axial direction during reciprocating motion, and preventing the first return spring 24 from twisting.

[0011] Furthermore, the first check valve 16 and the valve body 26 are integrated into one structure. The valve core of the first check valve 16 opens from the first flow channel 22 to the oil inlet chamber 17, allowing hydraulic oil to flow in this direction, ensuring a smooth hydraulic oil flow path when the boom descends, and reducing pressure loss.

[0012] Working principle:

[0013] When the boom is lifted: the oil in the rod chamber of the boom cylinder enters the diversion valve chamber 19 through the oil inlet chamber 17. The oil flow is divided by the area difference between the first throttling plate 14 and the second throttling plate 21 at both ends of the diversion valve 18. One path of oil acts on the upper end of the diversion valve 18 through the first throttling plate 14, pushing the diversion valve 18 to move along the diversion valve chamber 19 towards the first plug 12, so that the diversion valve chamber 19 is connected to the second flow channel 15. The oil pressure pushes open the valve core of the second check valve 1 and enters the first working chamber 2. The first working chamber 2 is connected to the rodless chamber of the bucket cylinder, so that the angle between the bucket and the ground remains unchanged when the boom cylinder is lifted. The other path of oil directly enters the first flow channel 22 through the second throttling plate 21, and then flows back to the oil tank through the oil outlet chamber 25.

[0014] When the boom lowers: hydraulic oil enters the first flow channel 22 through the oil outlet 25, and then flows into the lower chamber 20 of the first check valve. The oil pressure pushes open the valve core of the first check valve 16 and flows into the rod chamber of the boom cylinder from the oil inlet 17, realizing the lowering of the boom. During this process, the hydraulic oil forms an independent flow path through the first check valve 16, which effectively reduces the pressure loss of the hydraulic oil along the flow path, and avoids the turbulence noise generated by the oil flowing through the throttling plate, reducing abnormal noise.

[0015] Meanwhile, the centering plug 27 and the first plug 12 form a bidirectional limit on the diverter valve 18 along the axial direction of the diverter valve cavity 19, ensuring that the diverter valve 18 can only reciprocate along the axial direction. The two ends of the first return spring 24 are coaxially abutted with the diverter valve 18 and the centering plug 27 respectively, preventing the first return spring 24 from twisting during the extension and retraction process, ensuring that its return force is stable and reliable, thereby preventing the hydraulic oil from entering the rodless chamber of the bucket cylinder through the diverter valve 18 when the boom is lowered and overflowing, causing the bucket to swing out automatically.

[0016] Beneficial effects:

[0017] This utility model achieves axial directional movement of the diversion valve through the coaxial limiting structure of the centering plug and the first plug, combined with the coaxial assembly design of the first return spring. Structurally, it avoids the twisting of the first return spring, ensures stable return force, and completely solves the technical problem of automatic outward swing of the bucket when the boom is lowered and overflows, thereby improving operational safety and equipment stability.

[0018] By using the first check valve to create an independent hydraulic fluid flow path during boom descent, the hydraulic oil pressure loss is significantly reduced, turbulence noise is reduced, the problem of loud abnormal noise during boom descent is effectively solved, and the operating comfort is improved.

[0019] Each core component and valve body adopts an integrated design, which is compact and has high assembly precision. Furthermore, the dependent claims refine the local structures such as throttle plate fixing, check valve installation, and shut-off valve limit, which not only ensures the stable realization of the core functions, but also improves the product's adaptability and reliability, facilitates later maintenance and repair, and is suitable for hydraulic systems of various skid steer loaders. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of a skid steer loader lifting and leveling valve structure according to one embodiment of this application;

[0021] Explanation of reference numerals in the attached drawings: 1—Second check valve, 2—First working chamber, 3—Shut-off valve, 4—Lower chamber of relief valve, 5—Feedback channel of shut-off valve, 6—Third throttling plate, 7—Second working chamber, 8—Second return spring, 9—Lower chamber of shut-off valve, 10—Second plug, 11—Relief valve, 12—First plug, 13—First retaining ring, 14—First throttling plate, 15—Second flow channel, 16—First check valve, 17—Inlet chamber, 18—Diverter valve, 19—Diverter valve chamber, 20—Lower chamber of first check valve, 21—Second throttling plate, 22—First flow channel, 23—Second retaining ring, 24—First return spring, 25—Outlet chamber, 26—Valve body, 27—Centering plug. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present application, the technical solution of the present application will be further described in detail below with reference to the embodiments and accompanying drawings.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0024] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0025] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0026] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linked," and "socketing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0027] To overcome the defects of existing structures, this application provides a new lifting and leveling valve structure for skid steer loaders. By using a centering plug, the return spring of the diverter valve is prevented from twisting, which would reduce or eliminate the return force. This would prevent hydraulic oil from entering the rodless chamber of the bucket cylinder through the diverter valve during boom descent overflow, causing the bucket to automatically swing outward. By using a first check valve, when the boom is lowered, the oil inlet of the rod chamber of the boom cylinder flows in from the first flow channel 22 and the oil inlet chamber 17, reducing the pressure loss and abnormal noise during boom cylinder descent.

[0028] The following will refer to Figure 1 This application describes specific implementation methods.

[0029] like Figure 1 As shown in the figure, this application provides a skid steer loader lifting and leveling valve, including a valve body 26, which has a flow divider valve chamber 19, an oil inlet chamber 17, a first flow channel 22, a second flow channel 15 and a first one-way valve lower chamber 20.

[0030] A diversion valve 18 is installed within the diversion valve cavity 19. One end of the diversion valve 18 abuts against a first return spring 24, and the end of the first return spring 24 away from the diversion valve 18 abuts against a centering plug 27, which is fixedly mounted to one end port of the diversion valve cavity 19. The other end of the diversion valve 18 is positioned opposite to a first plug 12, which is also fixedly mounted to the other end port of the diversion valve cavity 19. The centering plug 27 and the first plug 12 form a bidirectional limiting effect on the diversion valve 18 along the axial direction of the diversion valve cavity 19. Thus, the displacement control and limiting of the diversion valve 18 can be achieved through the elastic force of the first return spring 24 and the bidirectional structural constraint of the first plug 26 and the centering plug 27.

[0031] A first one-way valve 16 is assembled between the lower chamber 20 of the first one-way valve and the oil inlet chamber 17. The first one-way valve 16 can control the connection and disconnection of the first flow channel 22 and the oil inlet chamber 17. Specifically, the valve core of the first one-way valve 16 is adapted to the flow channels of the lower chamber 20 of the first one-way valve and the oil inlet chamber 17, and is used to connect and disconnect the first flow channel 22 and the oil inlet chamber 17.

[0032] The oil inlet chamber 17 forms two connecting paths with the second flow channel 15 and the first flow channel 22 through the diversion valve chamber 19, namely the first connecting path of oil inlet chamber 17 → diversion valve chamber 19 → second flow channel 15, and the second connecting path of oil inlet chamber 17 → diversion valve chamber 19 → first flow channel 22; the valve port of the diversion valve 18 is adapted to the intersection of the two connecting paths, and the oil diversion is realized by switching the on and off states of the two connecting paths through the diversion valve 18.

[0033] Furthermore, a first throttling vane 14 and a second throttling vane 21 are respectively installed at both ends of the diversion valve 18, and are fixed to the inner cavity of the diversion valve 18 by a first retaining ring 13 and a second retaining ring 23. In one embodiment, the first throttling vane 14 and the second throttling vane 21 are respectively embedded in the inner cavities at both ends of the diversion valve 18, and the first retaining ring 13 and the second retaining ring 23 are respectively snapped at the two ends of the diversion valve 18. The first retaining ring 13 abuts against the side of the first throttling vane 14 away from the axis of the diversion valve 18, and the second retaining ring 23 abuts against the side of the second throttling vane 21 away from the axis of the diversion valve 18, so as to realize the axial fixation of the first throttling vane 14 and the second throttling vane 21 in the inner cavity of the diversion valve 18. By adjusting the area of ​​the two throttling vanes, the flow can be accurately diverted.

[0034] Furthermore, the valve body 26 is provided with a first working chamber 2, and a third flow channel is provided between the first working chamber 2 and the second flow channel 15. A second one-way valve 1 is installed in the third flow channel. The valve core of the second one-way valve 1 is adapted to the third flow channel to switch the first working chamber 2 and the second flow channel 15 on and off, so as to ensure the reliability of bucket leveling when the boom is lifted.

[0035] Furthermore, the valve body 26 is provided with a relief valve lower chamber 4, and a fourth flow channel is provided between the relief valve lower chamber 4 and the first flow channel 22. A relief valve 11 is installed in the fourth flow channel. The valve core of the relief valve 11 is adapted to the fourth flow channel to switch the second flow channel 15 and the first flow channel 22. The side of the valve core of the relief valve 11 facing the first flow channel 22 is the sealing surface to prevent hydraulic oil backflow and protect the hydraulic system components.

[0036] Furthermore, the valve body 26 is provided with a lower shut-off valve chamber 9 and a second working chamber 7. A fifth flow channel is provided between the lower shut-off valve chamber 9 and the second flow channel 15. A shut-off valve 3 is installed in the fifth flow channel. One end of the shut-off valve 3 abuts against a second return spring 8. The end of the second return spring 8 away from the shut-off valve 3 abuts against a third throttling plate 6. The third throttling plate 6 is fixedly installed in the fifth flow channel. The other end of the shut-off valve 3 is arranged opposite to the valve core of the second one-way valve 1. A second plug 10 is fixedly installed at the port of the fifth flow channel. The second plug 10 and the second one-way valve 1 are located on both sides of the shut-off valve 3, forming an axial limit on the shut-off valve 3. The valve body 26 is also provided with a shut-off valve feedback channel 5. One end of the shut-off valve feedback channel 5 is connected to the lower shut-off valve chamber 9, and the other end is connected to the first flow channel 22. The valve port of the shut-off valve 3 is adapted to the connecting flow channel between the lower shut-off valve chamber 9 and the second working chamber 7, and is used to switch the first flow channel 22 and the second working chamber 7 to achieve flexible switching of working state.

[0037] Furthermore, the diverter valve 18 and the valve body 26 are integrated into one structure. The centering plug 27 and the first plug 12 are both fixed to the two ends of the diverter valve cavity 19 by threaded connection. The axis of the centering plug 27 is collinear with the axis of the diverter valve cavity 19, and the axis of the first return spring 24 is collinear with the axis of the diverter valve 18, ensuring that the diverter valve 18 always moves along the axial direction during reciprocating motion, and preventing the first return spring 24 from twisting.

[0038] Furthermore, the first check valve 16 and the valve body 26 are integrated into one structure. The valve core of the first check valve 16 opens from the first flow channel 22 to the oil inlet chamber 17, allowing hydraulic oil to flow in this direction, ensuring a smooth hydraulic oil flow path when the boom descends, and reducing pressure loss.

[0039] In some embodiments, such as Figure 1 As shown, a skid steer loader lifting and leveling valve structure includes a valve body 26, on which are mounted a check valve 1, a shut-off valve 3, a throttle plate 3, a return spring 4, an overflow valve 11, a plug 6, a retaining ring 7, a throttle plate 8, a check valve 9, a flow divider valve 18, a throttle plate 21, a return spring 24, and a centering plug 27. The valve body 26 contains an oil outlet chamber 25, a first flow channel 22, a flow divider valve chamber 19, a lower chamber 20 of the first check valve, an oil inlet chamber 17, a second flow channel 15, a working chamber 2, a lower chamber 4 of the overflow valve, a feedback channel 5 of the shut-off valve, a working chamber 7, and a lower chamber 9 of the shut-off valve.

[0040] Working principle:

[0041] When the boom is lifted: the oil in the rod chamber of the boom cylinder enters the diversion valve chamber 19 through the oil inlet chamber 17. The oil flow is divided by the area difference between the first throttling plate 14 and the second throttling plate 21 at both ends of the diversion valve 18. One path of oil acts on the upper end of the diversion valve 18 through the first throttling plate 14, pushing the diversion valve 18 to move along the diversion valve chamber 19 towards the first plug 12, so that the diversion valve chamber 19 is connected to the second flow channel 15. The oil pressure pushes open the valve core of the second check valve 1 and enters the first working chamber 2. The first working chamber 2 is connected to the rodless chamber of the bucket cylinder, so that the angle between the bucket and the ground remains unchanged when the boom cylinder is lifted. The other path of oil directly enters the first flow channel 22 through the second throttling plate 21, and then flows back to the oil tank through the oil outlet chamber 25.

[0042] When the boom lowers: Hydraulic oil enters the first flow channel 22 through the outlet chamber 25, and then flows into the lower chamber 20 of the first check valve. The oil pressure opens the valve core of the first check valve 16, and the oil flows from the inlet chamber 17 into the rod chamber of the boom cylinder, realizing the lowering of the boom. During this process, the hydraulic oil forms an independent flow path through the first check valve 16, which effectively reduces the pressure loss of the hydraulic oil along the flow path, and avoids the turbulence noise generated by the oil flowing through the throttling plate, reducing abnormal noise.

[0043] Meanwhile, the centering plug 27 and the first plug 12 form a bidirectional limit on the diverter valve 18 along the axial direction of the diverter valve cavity 19, ensuring that the diverter valve 18 can only reciprocate along the axial direction. The two ends of the first return spring 24 are coaxially abutted with the diverter valve 18 and the centering plug 27 respectively, preventing the first return spring 24 from twisting during the extension and retraction process, ensuring that its return force is stable and reliable, thereby preventing the hydraulic oil from entering the rodless chamber of the bucket cylinder through the diverter valve 18 when the boom is lowered and overflowing, causing the bucket to swing out automatically.

[0044] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A lifting and leveling valve for a skid steer loader, characterized in that, The system includes a valve body (26), which contains a flow divider valve chamber (19), an oil inlet chamber (17), a first flow channel (22), a second flow channel (15), and a first check valve lower chamber (20). A flow divider valve (18) is installed in the flow divider valve chamber (19). One end of the flow divider valve (18) abuts against a first return spring (24), and the end of the first return spring (24) away from the flow divider valve (18) abuts against a centering plug (27). The centering plug (27) is fixedly installed at one end of the flow divider valve chamber (19). The other end of the flow divider valve (18) is opposite to the first plug (12), which is fixedly installed at the other end of the flow divider valve chamber (19). (27) and the first plug (12) form a bidirectional limit on the diverter valve (18) along the axis of the diverter valve cavity (19); a first one-way valve (16) is assembled between the first one-way valve lower cavity (20) and the oil inlet cavity (17). The valve core of the first one-way valve (16) is adapted to the flow channel of the first one-way valve lower cavity (20) and the oil inlet cavity (17) to open and close the first flow channel (22) and the oil inlet cavity (17); the oil inlet cavity (17) forms two connecting paths with the second flow channel (15) and the first flow channel (22) respectively through the diverter valve cavity (19); the valve port of the diverter valve (18) is adapted to the intersection of the two connecting paths, and the oil diversion is realized by switching the on and off state of the two connecting paths through the diverter valve (18).

2. The skid steer loader lifting and leveling valve according to claim 1, characterized in that, The inner cavities at both ends of the diversion valve (18) are respectively fitted with a first throttling plate (14) and a second throttling plate (21). At the two ends of the diversion valve (18), a first retaining ring (13) and a second retaining ring (23) are respectively clamped. The first retaining ring (13) abuts against the side of the first throttling plate (14) away from the axis of the diversion valve (18), and the second retaining ring (23) abuts against the side of the second throttling plate (21) away from the axis of the diversion valve (18), so as to achieve axial fixation of the first throttling plate (14) and the second throttling plate (21) in the inner cavity of the diversion valve (18).

3. The skid steer loader lifting and leveling valve according to claim 1, characterized in that, The valve body (26) is provided with a first working chamber (2), and a third flow channel is provided between the first working chamber (2) and the second flow channel (15). A second one-way valve (1) is assembled in the third flow channel. The valve core of the second one-way valve (1) is adapted to the third flow channel and is used to switch the first working chamber (2) and the second flow channel (15) on and off.

4. The skid steer loader lifting and leveling valve according to claim 1, characterized in that, The valve body (26) is provided with a relief valve lower chamber (4). A fourth flow channel is provided between the relief valve lower chamber (4) and the first flow channel (22). A relief valve (11) is installed in the fourth flow channel. The valve core of the relief valve (11) is adapted to the fourth flow channel to switch the second flow channel (15) and the first flow channel (22). The side of the valve core of the relief valve (11) facing the first flow channel (22) is a sealing surface to prevent hydraulic oil backflow.

5. The skid steer loader lifting and leveling valve according to claim 1, characterized in that, The valve body (26) is provided with a lower chamber (9) for the shut-off valve and a second working chamber (7). A fifth flow channel is provided between the lower chamber (9) for the shut-off valve and the second flow channel (15). A shut-off valve (3) is installed in the fifth flow channel. One end of the shut-off valve (3) abuts against a second return spring (8). The end of the second return spring (8) away from the shut-off valve (3) abuts against a third throttling plate (6). The third throttling plate (6) is fixedly installed in the fifth flow channel. The other end of the shut-off valve (3) is arranged opposite to the valve core of the second one-way valve (1), and the fifth flow channel... A second plug (10) is fixedly installed at the port of the valve. The second plug (10) and the second check valve (1) are located on both sides of the shut-off valve (3) to form an axial limit on the shut-off valve (3). The valve body (26) is also provided with a shut-off valve feedback channel (5). One end of the shut-off valve feedback channel (5) is connected to the lower chamber (9) of the shut-off valve, and the other end is connected to the first flow channel (22). The valve port of the shut-off valve (3) is adapted to the connecting flow channel between the lower chamber (9) of the shut-off valve and the second working chamber (7) to switch the first flow channel (22) and the second working chamber (7).

6. The skid steer loader lifting and leveling valve according to claim 1, characterized in that, The diversion valve (18) and the valve body (26) are an integrated structure. The centering plug (27) and the first plug (12) are both fixed to the two ends of the diversion valve cavity (19) by threaded connection. The axis of the centering plug (27) is collinear with the axis of the diversion valve cavity (19), and the axis of the first reset spring (24) is collinear with the axis of the diversion valve (18).

7. The skid steer loader lifting and leveling valve according to claim 1, characterized in that, The first check valve (16) and the valve body (26) are integrated into one structure. The valve core of the first check valve (16) opens from the first flow channel (22) to the oil inlet chamber (17), allowing hydraulic oil to flow only in this direction.

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