Machining clamp

Abstract

The invention discloses a machining clamp which comprises a bottom plate, a positioning mandrel and a movable positioning ring, the positioning mandrel and the movable positioning ring are arranged on the bottom plate, the positioning mandrel is fixedly arranged in the center of the movable positioning ring, the axis of the positioning mandrel is perpendicular to the bottom plate, and the movable positioning ring is arranged on the bottom plate. A first clamping ring and a second clamping ring which are used for limiting the movable positioning ring are arranged inside and outside the movable positioning ring respectively, and the movable positioning ring is indirectly connected with the bottom plate through an elastic piece. By arranging the elastic piece, the movable positioning ring is indirectly connected with the bottom plate through the elastic piece, vibration generated in the machining process can be effectively buffered, the cutter vibration phenomenon caused by suspension of a middle hub of a workpiece is avoided, and the machining surface quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of wheel hub processing, and in particular to a processing fixture. Background Art

[0002] The hub in the through-hole shaft is a common mechanical part. Figure 1 . The characteristics of this type of parts are that the core shaft is a through-hole shaft, and the outer part of the middle section is a hub structure, usually in the form of a gear. The reference of this type of parts is at the inner hole axis, and there are inner tapered holes (or center holes) at both ends of the shaft. When processing the middle hub, it is necessary to use the inner tapered holes (or center holes) at both ends for positioning. If it is supported by the bottom surface of the middle hub, it is bound to cause over-positioning. If it is not supported by the bottom surface of the middle hub, it will cause the middle hub to be suspended, and the tool will vibrate during processing. Usually, when processing this type of parts, the bottom surface of the middle hub is used for support, and then the inner tapered holes (or center holes) at both ends are used for active positioning. This will cause positioning clearance, which will affect the positioning accuracy. Summary of the invention

[0003] The main purpose of the present invention is to solve the technical problems described in the background technology.

[0004] To achieve the above-mentioned purpose, the present invention provides a processing fixture, including a base plate, a positioning mandrel and a movable positioning ring, the positioning mandrel and the movable positioning ring are arranged on the base plate, the positioning mandrel is fixedly arranged at the center position of the movable positioning ring, the axis of the positioning mandrel is perpendicular to the base plate, and the inside and outside of the movable positioning ring are respectively provided with a first clamping ring 2 and a second clamping ring 6 for limiting the movable positioning ring, and the movable positioning ring is indirectly connected to the base plate through an elastic member.

[0005] In one of the embodiments, an inclined groove is provided at one end of the movable positioning ring close to the bottom plate, and the movable positioning ring is limited by providing an inclined wedge to abut against the inclined surface of the inclined groove.

[0006] In one of the embodiments, a guide groove is provided at the lower end of the inclined wedge, and a guide pin corresponding to the position of the guide groove is provided on the bottom plate, and the guide pin is used to prevent the inclined wedge from rotating.

[0007] In one embodiment, the processing fixture further includes a cylinder and a reversing valve, the cylinder includes a piston rod, the wedge is installed on the piston rod, and the reversing valve is connected to the cylinder.

[0008] In one of the embodiments, the processing fixture further includes a positioning member and a nut. The nut is installed at an end of the positioning spindle away from the base plate. The positioning member abuts against a workpiece processed by the processing fixture through pressure generated by the rotation of the nut.

[0009] In one embodiment, a first conical positioning surface is provided at one end of the positioning member close to the workpiece, and a second conical positioning surface matching the conical positioning surface is provided on the positioning core shaft, and the first conical positioning surface and the second conical positioning surface form an upper and lower combined positioning for the workpiece.

[0010] In one of the embodiments, a washer is provided between the positioning member and the nut.

[0011] In one of the embodiments, the positioning mandrel is fixed to the base plate via an anti-rotation pin.

[0012] In one of the embodiments, a step hook is provided at the lower end of the movable positioning ring to prevent the axis from slipping out.

[0013] In one embodiment, the elastic member is a spring.

[0014] The present invention provides an elastic member so that the movable positioning ring is indirectly connected to the base plate through the elastic member, which can effectively buffer the vibration generated during the processing, avoid the tool vibration phenomenon caused by the suspended hub in the workpiece, and improve the processing surface quality. At the same time, the first clamping ring and the second clamping ring are provided to limit the movable positioning ring, thereby ensuring the stability of the movable positioning ring during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 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. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of a hub in a through-hole shaft in one embodiment of the present invention;

[0017] Figure 2 It is a schematic diagram of the assembly of a workpiece (a hub in a through-hole shaft) and a processing fixture (left) and a schematic diagram of the structure of a reversing valve (right) in one embodiment of the present invention;

[0018] Figure 3 It is a schematic cross-sectional structure diagram of a processing fixture in one embodiment of the present invention;

[0019] Component symbols in the figure:

[0020] 1. Base plate; 2. First retaining ring; 3. Spring; 4. Positioning mandrel; 5. Anti-rotation pin; 6. Second retaining ring; 7. Guide pin; 8. Wedge; 9. Cylinder; 10. Reversing valve; 11. Movable positioning ring; 12. Workpiece; 13. Positioning piece; 14. Washer; 15. Nut. DETAILED DESCRIPTION

[0021] In order to better understand the above technical solution, exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0022] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0023] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the coordinate system shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0024] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0026] The present invention provides a processing fixture, which is used to fix a hub part in a through-hole shaft so that it can be processed. The processing fixture includes a base plate 1, a positioning mandrel 4 and a movable positioning ring 11. The positioning mandrel 4 and the movable positioning ring 11 are arranged on the base plate 1. The positioning mandrel 4 is fixedly arranged at the center position of the movable positioning ring 11. The axis of the positioning mandrel 4 is perpendicular to the base plate 1. The first retaining ring 2 and the second retaining ring 6 for limiting the movable positioning ring 11 are respectively arranged outside and inside the circle of the movable positioning ring 11. The movable positioning ring 11 is indirectly connected to the base plate 1 through an elastic member.

[0027] It should be understood that the present invention aims to solve the problems of over-positioning, tool vibration and low positioning accuracy in the existing positioning method during the processing of the hub in the through-hole shaft. Specifically, it is to avoid the over-positioning phenomenon caused by unreasonable positioning; eliminate the problem of tool vibration caused by the suspension of the hub; overcome the influence of the positioning gap on the positioning accuracy in the existing active positioning method, thereby improving the processing accuracy, ensuring the processing quality, and meeting the requirements of the mechanical processing industry for high-precision parts processing. In the traditional positioning method, when the inner tapered holes (or center holes) at both ends are used for active positioning, in order to ensure the flexibility of active positioning, there must be a certain gap between the positioning element and the positioning surface of the workpiece 12. During the processing, the workpiece 12 will produce a small displacement within this gap range due to factors such as cutting force and vibration. For example, when turning the outer circle of the hub, the direction and magnitude of the cutting force are constantly changing, and the workpiece 12 will swing within the range allowed by the gap, resulting in the size accuracy and shape accuracy after processing being affected, and the requirements of high-precision processing cannot be met; the combination of the support of the bottom surface of the hub and the active positioning of the inner tapered holes (or center holes) at both ends makes the positioning reference not unique and has a certain uncertainty. When positioning different workpieces 12, due to manufacturing errors and other reasons, the relative positions between the bottom surface of the center hub and the inner tapered holes (or center holes) at both ends will be different, which further amplifies the influence of the positioning clearance on the positioning accuracy. For example, among a batch of workpieces 12, the flatness of the bottom surface of the center hub of some workpieces 12 has errors, which will cause different degrees of inclination when supported, and the clearance of the active positioning will eventually lead to different actual positioning positions of each workpiece 12 during processing, and the processing accuracy is difficult to guarantee.

[0028] The lower part of the positioning mandrel 4 is tightly connected with the bottom plate 1 to keep the axis perpendicular to the bottom surface. The first clamp ring 2 and the second clamp ring 6 can be fixed on the bottom plate 1 by (multiple) fixing pins and other fastening elements; the outer diameter of the movable positioning ring 11 is smaller than the outer diameter of the middle hub surface of the workpiece 12, the inner diameter of the movable positioning ring 11 is larger than the outer diameter of the positioning mandrel 4, and the diameter of the positioning mandrel 4 is slightly smaller than the diameter of the middle hole shaft of the hub member in the through hole shaft (refer to Figure 1 and Figure 2), there is a certain gap between the two; the elastic coefficient of the elastic member is calculated and determined according to the weight of the workpiece 12 and the expected processing vibration, and is installed between the base plate 1 and the movable positioning ring 11 to ensure that the verticality and pre-compression of the elastic member are appropriate. The elastic member is evenly arranged between the base plate 1 and the movable positioning ring 11, which can make the elastic force on the movable positioning ring 11 in all directions more uniform. This helps the movable positioning ring 11 to move or reset more smoothly when subjected to external force, ensuring its stability and reliability during the working process.

[0029] In this embodiment, the positioning mandrel 4 is fixed at the center of the movable positioning ring 11 and is perpendicular to the base plate 1, which ensures the coaxiality of the workpiece 12 and improves the processing accuracy. The first retaining ring 2 and the second retaining ring 6 limit the movable positioning ring 11, mainly to ensure the stability of the movable positioning ring 11 in the radial direction and prevent it from radial displacement during the processing. The movable positioning ring 11 is indirectly connected to the base plate 1 through an elastic member, which can effectively buffer the vibration generated during the processing, avoid the vibration of the tool caused by the hub of the workpiece 12 hanging in the air, and improve the processing surface quality.

[0030] In one of the embodiments, an inclined groove is provided at one end of the movable positioning ring 11 close to the bottom plate 1 , and the movable positioning ring 11 is limited by providing an inclined wedge 8 to abut against the inclined surface of the inclined groove.

[0031] Among them, the inclined groove is evenly arranged at one end of the movable positioning ring 11 close to the bottom plate 1 to ensure that the cooperation between the inclined wedge 8 and the inclined groove is more stable and balanced. In this way, when the movable positioning ring 11 is limited by the inclined wedge 8, the limiting force exerted on the movable positioning ring 11 is evenly distributed in the circumferential direction, which is conducive to improving the positioning accuracy and stability of the movable positioning ring 11 and ensuring that it will not deviate or shake during the processing; refer to Figure 1 and Figure 2 , five inclined grooves are evenly arranged on the movable positioning ring 11, and the distance between each inclined groove is equal.

[0032] Specifically, five inclined grooves with an angle of 45° and a depth of 5mm are machined at one end of the movable positioning ring 11 close to the bottom plate 1. The inclined wedge 8 is made of Cr12MoV tool steel, and after quenching and tempering, the hardness reaches HRC58-62. The inclined surface of the inclined wedge 8 is accurately machined according to the size of the inclined groove, so that the matching clearance between it and the inclined surface of the inclined groove does not exceed 0.05mm. When installing the inclined wedge 8, ensure that its inclined surface fits tightly with the inclined groove on the movable positioning ring 11; when the clamp is working, the gravity of the workpiece 12 and other external forces make the movable positioning ring 11 approach the bottom plate 1, thereby compressing the elastic member. As the elastic member is compressed, its length becomes shorter. At this time, the distance between the lower end of the inclined groove and the bottom plate 1 will also become smaller accordingly. In order to ensure that the inclined groove can work normally, such as maintaining a good fit with the inclined wedge 8 to limit the movable positioning ring 11, the distance variation range between the lower end of the inclined groove and the bottom plate 1 needs to match the compression amount of the elastic member.

[0033] In this embodiment, the inclined wedge 8 abuts against the inclined surface of the inclined groove of the movable positioning ring 11 to limit the position, which can effectively prevent the movable positioning ring 11 from moving downward due to external forces such as cutting force during the processing, thereby enhancing the stability of the movable positioning ring 11 and further improving the positioning accuracy of the workpiece 12.

[0034] In one of the embodiments, a guide groove is provided at the lower end of the inclined wedge 8, and a guide pin 7 corresponding to the position of the guide groove is provided on the base plate 1, and the guide pin 7 is used to prevent the inclined wedge 8 from rotating.

[0035] Among them, the processing accuracy requirements of the guide groove at the lower end of the bevel wedge 8 and the guide pin 7 on the base plate 1 are high, and the matching clearance between the guide groove and the guide pin 7 must be strictly controlled within a preset range to ensure that the bevel wedge 8 can move smoothly along the guide pin 7 and effectively prevent the bevel wedge 8 from rotating.

[0036] In this embodiment, the cooperation between the guide pin 7 and the guide groove at the lower end of the inclined wedge 8 effectively prevents the inclined wedge 8 from rotating during movement, so that the inclined wedge 8 can stably limit the movable positioning ring 11, ensuring the stability and reliability of the entire positioning system.

[0037] In one embodiment, the processing fixture further includes a cylinder 9 and a reversing valve 10 , the cylinder 9 includes a piston rod, the wedge 8 is installed on the piston rod, and the reversing valve 10 is connected to the cylinder 9 .

[0038] When in use, the reversing valve 10 can be installed outside the working table of the machine tool.

[0039] In this embodiment, the arrangement of the cylinder 9 and the reversing valve 10 realizes the automatic control of the bevel wedge 8, and the operation is simple and fast. The reversing valve 10 controls the extension and contraction of the cylinder 9, and can quickly lock and release the movable positioning ring 11, thereby improving the processing efficiency, and is more accurate and stable than manual operation.

[0040] In one embodiment, the processing fixture further includes a positioning member 13 and a nut 15. The nut 15 is installed at one end of the positioning spindle 4 away from the base plate 1. The positioning member 13 abuts against the workpiece 12 processed by the processing fixture through the pressure generated by the rotation of the nut 15.

[0041] In this embodiment, an external thread is provided at one end of the positioning core shaft 4 away from the base plate 1, and the nut 15 is threadedly connected to the positioning core shaft 4. The nut 15 is rotated to drive the positioning member 13 to abut against the workpiece 12, thereby clamping the workpiece 12. The operation is simple and convenient, and the clamping force can be flexibly adjusted according to actual needs, ensuring that the workpiece 12 will not be displaced during the processing, thereby improving the stability of the processing.

[0042] In one embodiment, a first conical positioning surface is provided at one end of the positioning member 13 close to the workpiece 12, and a second conical positioning surface matching the conical positioning surface is provided on the positioning core shaft 4, and the first conical positioning surface and the second conical positioning surface form an upper and lower combined positioning for the workpiece 12.

[0043] The machining accuracy requirements for the first conical positioning surface and the second conical positioning surface are extremely high, and the tapers of the two are the same and must be consistent with the design reference of the workpiece 12.

[0044] In this embodiment, the first conical positioning surface and the second conical positioning surface form an upper and lower combined positioning for the workpiece 12, which can achieve high-precision centering and positioning of the workpiece 12, automatically compensate for the manufacturing errors of the workpiece 12 and the positioning elements, and improve the processing accuracy. It is particularly suitable for the processing of workpieces 12 with high coaxiality requirements.

[0045] In one embodiment, a washer 14 is disposed between the positioning member 13 and the nut 15 .

[0046] The size of the washer 14 should be compatible with the nut 15 and the positioning member 13, and its inner diameter should be slightly larger than the outer diameter of the positioning mandrel 4, and its outer diameter should be larger than the outer diameter of the nut 15 to ensure that the pressure can be effectively dispersed; it should be noted that if Figure 1-3 As shown, the positioning mandrel 4 will be designed with a corresponding shape according to the central axis of the workpiece 12, so the outer diameter / inner diameter of the positioning mandrel 4 mentioned in the specification should refer to the outer diameter / inner diameter of the said parts (such as gasket 14, movable positioning ring 11) at the corresponding position on the positioning mandrel 4.

[0047] In this embodiment, the provision of the washer 14 increases the contact area between the nut 15 and the positioning member 13, which can evenly disperse the pressure generated by the rotation of the nut 15, prevent the nut 15 from causing damage to the positioning member 13 during the tightening process, and also help prevent the nut 15 from loosening, thereby ensuring the stability of the clamping force.

[0048] In one embodiment, the positioning mandrel 4 is fixed to the base plate 1 via an anti-rotation pin 5 .

[0049] Among them, the material of the anti-rotation pin 5 should have high strength and hardness, such as selecting 40Cr alloy steel and quenching it; the anti-rotation pin 5 can be driven into the bottom side of the positioning core shaft 4 to prevent the positioning core shaft 4 from rotating.

[0050] In this embodiment, the anti-rotation pin 5 fixes the positioning spindle 4, effectively preventing the positioning spindle 4 from rotating due to external force during the processing, ensuring the stability of the positioning spindle 4, thereby improving the positioning accuracy of the entire fixture and ensuring the accurate position of the workpiece 12 during the processing.

[0051] In one of the embodiments, a step hook is provided at the lower end of the movable positioning ring 11 to prevent the axis from slipping out.

[0052] Among them, the size design of the step hook at the lower end of the movable positioning ring 11 should be reasonable, which can not only ensure that the movable positioning ring 11 can be effectively prevented from axially disengaging, but also cannot affect the normal activity of the movable positioning ring 11. Correspondingly, a groove matching the step groove is provided at the position corresponding to the second retaining ring 6 and the step groove, so that the step hook has normal activity space.

[0053] In this embodiment, the step hook at the lower end of the movable positioning ring 11 provides axial limitation for the movable positioning ring 11, preventing the movable positioning ring 11 from axially dislodging during processing, thereby enhancing the stability and reliability of the fixture structure.

[0054] In one embodiment, the elastic member is a spring 3 .

[0055] The selection of spring 3 should comprehensively consider factors such as the weight of workpiece 12, vibration during processing, and required support force, and select appropriate specifications of spring 3, including the diameter, number of coils, elastic coefficient, etc. of spring 3. When installing spring 3, its verticality should be ensured to avoid skewness that causes uneven force. At the same time, the fatigue life of spring 3 should be considered, and spring 3 should be regularly inspected and replaced to ensure its stable performance.

[0056] In this embodiment, the spring 3 as an elastic member has the advantages of low cost, easy installation, stable elastic performance, etc. It can provide a stable support force for the movable positioning ring 11, buffer the vibration during the processing, effectively reduce the vibration of the tool during processing, and improve the processing quality.

[0057] In one embodiment, a processing fixture includes a base plate 1, a positioning spindle 4 and a movable positioning ring 11, wherein the positioning spindle 4 and the movable positioning ring 11 are arranged on the base plate 1, the positioning spindle 4 is fixedly arranged at the center position of the movable positioning ring 11, the axis of the positioning spindle 4 is perpendicular to the base plate 1, and the outer and inner parts of the movable positioning ring 11 are respectively provided with a first retaining ring 2 and a second retaining ring 6 for limiting the movable positioning ring 11, and the movable positioning ring 11 is indirectly connected to the base plate 1 through a spring 3; an inclined groove is provided at one end of the movable positioning ring 11 close to the base plate 1, and the movable positioning ring 11 is limited by providing an inclined wedge 8 that abuts against the inclined surface of the inclined groove; a guide groove is provided at the lower end of the inclined wedge 8, and a guide pin 7 corresponding to the position of the guide groove is provided on the base plate 1, and the guide pin 7 is used to prevent the inclined wedge 8 from rotating; the processing fixture also includes a pneumatic Cylinder 9 and reversing valve 10, the cylinder 9 includes a piston rod, the inclined wedge 8 is installed on the piston rod, and the reversing valve 10 is connected to the cylinder 9; the processing fixture also includes a positioning piece 13 and a nut 15, the nut 15 is installed at the end of the positioning core shaft 4 away from the base plate 1, and the positioning piece 13 abuts against the workpiece 12 processed by the processing fixture through the pressure generated by the rotation of the nut 15; the positioning piece 13 is provided with a first conical positioning surface at the end close to the workpiece 12, and the positioning core shaft 4 is provided with a second conical positioning surface that cooperates with the conical positioning surface, and the first conical positioning surface and the second conical positioning surface form an upper and lower combined positioning for the workpiece 12; a washer 14 is provided between the positioning piece 13 and the nut 15; the positioning core shaft 4 is fixed to the base plate 1 by an anti-rotation pin 5; the lower end of the movable positioning ring 11 is provided with a step hook for preventing the axis from slipping out.

[0058] Specifically, the reversing valve 10 is mounted on the workbench of the machine tool, the integral fixture on the base plate 1 is fixed on the workbench of the machine tool, the nut 15 is unscrewed, the washer 14 and the positioning member 13 are removed, the workpiece 12 is inserted into the positioning mandrel 4 in the specified direction, and then Figure 2 and Figure 3 As shown, the positioning piece 13, washer 14 and nut 15 are gradually put in, and the nut 15 is tightened. The workpiece 12 is positioned and pressed in the processing fixture. At the same time, the movable positioning ring 11 is pressed down by the workpiece 12 to keep in contact with the bottom surface of the middle hub of the workpiece 12. Then, the handle of the reversing valve 10 is pulled to control the extension of the cylinder 9, and the inclined wedge 8 installed on the piston rod is pushed out to lock the current position of the movable positioning ring 11. During processing, the movable positioning ring 11 bears the cutting force. After processing, the above steps are reversed to take out the processed workpiece 12 and enter the next workpiece processing.

[0059] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A processing fixture, characterized in that: The processing fixture includes a base plate, a positioning mandrel and a movable positioning ring, the positioning mandrel and the movable positioning ring are arranged on the base plate, the positioning mandrel is fixedly arranged at the center position of the movable positioning ring, the axis of the positioning mandrel is perpendicular to the base plate, and the first and second retaining rings for limiting the movable positioning ring are respectively arranged inside and outside the circle of the movable positioning ring, and the movable positioning ring is indirectly connected to the base plate through an elastic member.

2. The processing fixture according to claim 1, characterized in that: An oblique groove is arranged at one end of the movable positioning ring close to the bottom plate, and the movable positioning ring is limited by arranging an oblique wedge to abut against the inclined surface of the oblique groove.

3. The processing fixture according to claim 2, characterized in that: A guide groove is arranged at the lower end of the inclined wedge, and a guide pin corresponding to the position of the guide groove is arranged on the bottom plate, and the guide pin is used to prevent the inclined wedge from rotating.

4. The processing fixture according to claim 2, characterized in that: The processing fixture also includes a cylinder and a reversing valve. The cylinder includes a piston rod, the wedge is installed on the piston rod, and the reversing valve is connected to the cylinder.

5. The processing fixture according to claim 1, characterized in that: The processing fixture further comprises a positioning member and a nut. The nut is mounted on an end of the positioning spindle away from the base plate. The positioning member abuts against a workpiece processed by the processing fixture through pressure generated by the rotation of the nut.

6. The processing fixture according to claim 5, characterized in that: The positioning member is provided with a first conical positioning surface at one end close to the workpiece, and the positioning mandrel is provided with a second conical positioning surface matched with the conical positioning surface, and the first conical positioning surface and the second conical positioning surface form an upper and lower combined positioning for the workpiece.

7. The processing fixture according to claim 1, characterized in that: A washer is arranged between the positioning piece and the nut.

8. The processing fixture according to claim 1, characterized in that: The positioning mandrel is fixed to the base plate via an anti-rotation pin.

9. The processing fixture according to claim 1, characterized in that: The lower end of the movable positioning ring is provided with a step hook for preventing the axis from slipping out.

10. The processing fixture according to claim 1, characterized in that: The elastic member is a spring.

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