A piston head clamping tool

Abstract

This utility model provides a piston head clamping fixture, including a cylindrical spring clamp body and a machine tool locking sleeve. The locking sleeve has an axially penetrating mounting hole, and the spring clamp body is axially movable and inserted into the mounting hole. The spring clamp body has a connecting end and a clamping end at its two ends, respectively. The connecting end is connected to a driving component, and the clamping end extends outside the locking sleeve. The end face of the clamping end has an inwardly recessed groove to accommodate the piston head. The clamping end has several axially extending, radially penetrating dividing grooves, evenly distributed circumferentially, dividing the clamping end into several clamping arms. The outer wall of the clamping end of each clamping arm has a first conical surface, and the inner wall of the mounting hole has a second conical surface. Each clamping arm has a locking part located outside the locking sleeve. This fixture relies on the conical surface to achieve initial radial clamping, and then the locking part applies additional radial locking force, forming a double constraint on the piston head. This overcomes the problem of circumferential slippage of the workpiece caused by friction welding under high speed and high torque conditions, improving welding accuracy and product yield.

Description

Technical Field

[0001] This utility model relates to the field of clamping tooling technology, specifically to a piston head clamping tooling. Background Technology

[0002] In the manufacturing process of actuators such as hydraulic cylinders or pneumatic cylinders, friction welding of the piston head and piston rod is an efficient process for achieving a fixed connection between the two. This process typically relies on the machine tool spindle driving the piston head to rotate at high speed, generating frictional heat with the piston rod end under axial pressure, thereby achieving a solid-state connection. During this process, the clamping stability of the piston head directly determines the alignment accuracy and thermal coupling uniformity of the weld interface.

[0003] Currently, spring collets are widely used in the industry for clamping and positioning piston heads. For example, a spring collet disclosed in Chinese Utility Model Patent (Publication No. CN205437203U) includes a sleeve, a clamping hole, and several collets. A gap is provided between adjacent collets, extending from the collets to the sleeve. The inner wall of the clamping hole is uniformly provided with anti-slip textures. This type of spring collet relies on the clamping force of the collets combined with the anti-slip textures to firmly hold the workpiece, offering advantages such as simple structure and convenient operation.

[0004] However, in practical applications of piston head friction welding, the aforementioned spring collets exhibit significant limitations. During friction welding, the machine tool spindle needs to drive the piston head to rotate continuously at speeds of several thousand revolutions per minute. The welding interface generates substantial frictional torque and vibration loads, placing high demands on the clamping reliability of the tooling fixture. The outer circumferential wall of existing piston heads is typically a smooth, ground surface. Even with anti-slip grooves in the collet's clamping holes, circumferential relative sliding (i.e., slippage) can still easily occur between the smooth outer surface of the piston head and the inner wall of the collet under the high torque impact of friction welding. Once circumferential slippage occurs, the spring collet cannot effectively drive the piston head to the preset welding speed. At this point, the piston rod continues to apply axial pushing force, further exacerbating the slippage problem. This can easily lead to various welding defects such as discontinuous weld formation, uneven weld thickness distribution, and incomplete weld joints, ultimately resulting in difficulty in ensuring the connection accuracy of the welded joint and a decrease in the yield of friction welded piston heads and piston rods.

[0005] Therefore, there is an urgent need to develop clamping fixtures that are suitable for friction welding of piston heads, in order to solve the problem of insufficient reliability of existing spring collets. Utility Model Content

[0006] This invention addresses the technical problem of insufficient clamping force in existing spring collets during piston head friction welding, leading to circumferential slippage of the piston head and ultimately affecting welding quality. To overcome the shortcomings of the prior art, this invention provides a piston head clamping fixture. By adding a locking part to the conical clamping base, additional radial locking force is provided, doubly constraining the piston head. Furthermore, the locking part applies controllable and uniform radial locking force to the piston head from multiple points circumferentially, overcoming the defect of circumferential slippage between the piston head and the fixture under friction welding conditions of high speed, large friction torque, and vibration impact. This avoids welding defects such as discontinuous weld formation, uneven weld thickness, and incomplete weld joints caused by slippage, improving the connection accuracy of piston head and piston rod friction welding and increasing the welding yield.

[0007] To achieve the purpose of this utility model, the following technical solution is adopted: A piston head clamping fixture includes a cylindrical spring clamp body and a locking sleeve mounted on a machine tool. The locking sleeve has an axially penetrating mounting hole. The spring clamp body is movably inserted into the mounting hole along the axial direction, with a connecting end and a clamping end at its two axial ends, respectively. The connecting end is connected to a driving component for driving the axial movement of the spring clamp body. The clamping end extends beyond the locking sleeve, and its end face is recessed with a clamping groove for accommodating a piston head. The end face of the clamping end also has several axially extending dividing grooves, each of which radially penetrates the spring clamp. The body has an inner and outer wall; all the dividing grooves are evenly distributed along the circumference of the spring clamp body, and the clamping end is evenly divided to form a number of clamping arms; the outer wall of the clamping end of each clamping arm is provided with a first conical surface, and the inner wall of the mounting hole near the clamping end is provided with a second conical surface that cooperates with the first conical surface. The spring clamp body is driven to move axially by the driving component, so that the clamping arm can be retracted and clamped under the action of the two conical surfaces; a locking part is provided on the clamping end of each clamping arm and on the outside of the locking sleeve. The locking part applies a radial force to the piston head to fix the piston head in the clamping groove. This fixture achieves axial positioning and limiting of the piston head through a clamping groove, ensuring the accuracy of piston head clamping and centering. A multi-lobed clamping arm is formed through a partition groove, and the locking sleeve and the conical surface of the spring clamp body cooperate to achieve radial clamping of the clamping end, completing the initial positioning. Furthermore, a locking part is added on top of the conical clamping to provide additional radial locking force, doubly constraining the piston head. This overcomes the defect of circumferential slippage between the piston head and the fixture under high-speed, high-friction torque, and vibration impact conditions in friction welding, thereby avoiding welding defects such as discontinuous weld formation, uneven weld thickness, and incomplete joint welding caused by slippage. This improves the connection accuracy of the friction welded joint between the piston head and piston rod, and increases the welding yield.

[0008] Preferably, the locking part includes a locking hole that penetrates the clamping arm radially, and a locking member that is radially movable and connected to the locking hole. In the locked state, the radially inner end of the locking member abuts against the outer wall of the piston head. By directly pressing the outer wall of the piston head with the radial movement of the locking member, a radial clamping force can be provided independently. This force, combined with the clamping force of the clamping arm from the conical surface, forms a compound clamping force, further resisting the circumferential torque during the friction welding process and providing stronger anti-slip capability. Furthermore, the radial adjustment of the locking member allows it to adapt to piston head workpieces with a certain outer diameter tolerance range, resulting in strong clamping adaptability. The abutment clamping assembly structure is simple and facilitates maintenance and replacement of clamping parts.

[0009] Preferably, the locking hole is a threaded hole, and the locking element is a locking screw that mates with the threaded hole. This locking structure using a threaded hole and locking screw is not only simple and inexpensive, with readily available and universal parts, but also convenient to adjust. The screw tightening force can be flexibly adjusted according to workpiece size and working conditions. Furthermore, the threaded connection has self-locking properties; even under the continuous high-frequency vibration environment of friction welding, the locking screw is not prone to loosening or retraction, maintaining a stable radial locking force over a long period, significantly improving clamping reliability and process consistency.

[0010] Preferably, the spring clip body includes a conical section, an inner concave section, and an outer circular section arranged sequentially from the clamping end to the connecting end. The first conical surface is disposed on the conical section, and the diameter of the conical section gradually narrows from the clamping end to the connecting end. The outer diameter of the inner concave section is smaller than the minimum outer diameter of the conical section and the outer diameter of the outer circular section. By setting the first conical surface on the conical section and cooperating with the second conical surface of the locking sleeve, the axial tensile force is converted into radial clamping force, realizing the reliable retraction and clamping of the workpiece by the clamping arm. By reducing the diameter of the inner concave section, a stress avoidance area is formed. When the spring clip body is axially pulled and the clamping arm elastically opens and closes, the deformation is mainly concentrated in the avoidance section, reducing residual stress in other parts of the body, improving the fatigue resistance of the spring clip body, and extending the service life of the tooling. Furthermore, the reduced diameter of the inner concave section reserves deformation space, reducing the risk of plastic deformation when the spring clip body opens and closes, and ensuring the elastic recovery ability of the clamping arm after repeated clamping and releasing.

[0011] Preferably, the conical segment is coaxially connected to an annular segment near the clamping end; the locking hole is radially penetrated through the outer wall of the annular segment. The annular segment provides sufficient wall thickness for the radial locking hole, avoiding a significant decrease in the clamping arm's strength caused by directly opening a hole in the thin-walled clamping arm, thus ensuring the structural strength of the clamping arm. Furthermore, the locking screw is positioned on the annular segment, away from the stress concentration area at the root of the partition groove, ensuring that the opening does not damage the elastic deformation area of ​​the clamping arm, balancing locking installation requirements with the elastic deformation performance of the clamping arm. Simultaneously, the annular segment is closer to the workpiece side, and the locking component's clamping position is close to the piston head clamping position, allowing the clamping force to act directly on the workpiece end. This results in a short lever arm, high clamping efficiency, reduced risk of workpiece tipping and displacement, and further ensures alignment accuracy.

[0012] Preferably, the clamping groove extends axially through the spring clamp body, and the outer peripheral wall of the concave section is provided with several stress relief grooves extending radially through it. These stress relief grooves are evenly arranged circumferentially along the concave section, and each stress relief groove corresponds one-to-one with a partition groove. Each stress relief groove extends axially and connects to its corresponding partition groove. Through the connection between the stress relief grooves and the partition grooves, stress can be released when the spring clamp body clamps and expands, reducing stress concentration caused by clamping deformation and preventing breakage at the root of the clamping arm. This further enhances the elasticity of the spring clamp body during repeated opening and closing, reduces the probability of plastic deformation, and improves the durability of the tooling. Furthermore, the evenly arranged stress relief grooves ensure consistent deformation of each clamping arm, uniform shrinkage of the multi-lobed clamping arms, and improve the coaxiality and alignment accuracy of the piston head clamping.

[0013] Preferably, the dividing groove extends to the concave section and communicates with the corresponding stress relief groove, and the width of the stress relief groove is greater than the width of the dividing groove. The wider stress relief groove further releases deformation stress from the clamping arm, improving the stress relief effect. The extension of the dividing groove to the stress relief groove extends the deformation area of ​​the clamping arm to the concave section, further enhancing the elasticity of the clamping arm, reducing the risk of cracking under clamping load, and improving the fatigue resistance of the tooling.

[0014] Preferably, the outer peripheral wall of the concave section is provided with at least one anti-rotation part, and the locking sleeve is provided with a limiting part corresponding to the anti-rotation part. The limiting part cooperates with the anti-rotation part to restrict the circumferential rotation of the spring clip body relative to the locking sleeve. During friction welding, the spindle torque is transmitted to the spring clip body through the locking sleeve. The anti-rotation structure prevents the spring clip body from slipping circumferentially relative to the locking sleeve, ensuring that the spindle torque is completely transmitted to the clamped piston head. This further eliminates the relative circumferential rotation between the spring clip body and the locking sleeve, reduces internal wear of the tooling, avoids loss of workpiece speed due to slippage of the body, and further ensures the stability of the welding process speed.

[0015] Preferably, the anti-rotation part is an anti-rotation through hole radially formed on the outer wall of the concave section, and the limiting part includes a mating hole radially penetrating the locking sleeve and a limiting pin threaded into the mating hole. The limiting pin passes through the mating hole and is inserted into the anti-rotation through hole to achieve circumferential limiting of the spring clip body. The circumferential locking of the spring clip body is achieved by the cooperation of the limiting pin, the mating hole and the anti-rotation through hole, preventing the spring clip body from circumferentially moving with torque, ensuring the stability of the working position of the entire tooling set, and facilitating easy assembly and disassembly.

[0016] Preferably, the driving component is a drive rod distributed along the axial direction, and one end of the drive rod is fixedly connected to the connecting end of the spring clip body. The drive rod structure is simple and easy to implement.

[0017] The advantages of this invention are: The use of a conical surface fit allows the clamping arm to initially grip the piston head, and the locking part applies additional radial locking force to form a double constraint, effectively overcoming the problem of piston head circumferential slippage under high-speed, high-torque, and vibration conditions in friction welding. This reduces defects such as discontinuous welds, uneven thickness, and incomplete welds, improving the accuracy and yield of the welded joint. The spring clip body is equipped with a reduced-diameter avoidance section and a stress relief groove connected to the partition groove, which can guide and release deformation stress, reduce stress concentration, reduce plastic deformation, and improve the fatigue resistance and service life of the tooling. The annular section is equipped with a locking structure to ensure the structural strength of the clamping arm, and the clamping position is close to the workpiece, resulting in higher clamping and centering accuracy. An anti-rotation limiting structure is set between the locking sleeve and the spring clip body to prevent relative circumferential rotation of the tooling body, ensuring complete transmission of spindle torque. The drive pull rod provides uniform axial tension. The overall design adopts a mature spring clip assembly form, which is compatible with existing friction welding machine tools. Workpiece disassembly and assembly are convenient, and parts are easy to maintain and replace, balancing clamping reliability and equipment versatility. Attached Figure Description

[0018] Figure 1 is a schematic diagram of the piston head clamping fixture of this utility model.

[0019] Figure 2 is a cross-sectional view of the piston head clamping fixture of this utility model.

[0020] Figure 3 is a schematic diagram of the structure of the spring clip body of this utility model.

[0021] Figure 4 is a cross-sectional view of the spring clip body of this utility model.

[0022] Explanation of reference numerals in the attached figures: 1. Spring clip body; 10. Clamping arm; 101. Conical section; 102. Concave section; 103. Outer circular section; 104. Circular section; 11. Clamping end; 12. Connecting end; 13. Clamping groove; 14. Separating groove; 15. Stress relief groove; 16. Anti-rotation through hole; 2. Locking part; 21. Locking hole; 3. Locking sleeve; 31. Mounting hole; 32. Mating hole. Detailed Implementation

[0023] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0024] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0025] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] like Figures 1 to 4As shown, a piston head clamping fixture includes a cylindrical spring clamp body 1 and a locking sleeve 3 mounted on a machine tool. The locking sleeve 3 has an axially penetrating mounting hole 31 at its center. The spring clamp body 1 is movably inserted into the mounting hole 31 along the axial direction, and the two axial ends of the spring clamp body 1 are a connecting end 12 (right end) and a clamping end 11 (left end), respectively. The connecting end 12 is connected to a driving component (driving rod) for driving the axial movement of the spring clamp body 1. The clamping end 11 extends beyond the locking sleeve 3, and the outer peripheral wall of the clamping end 11 has a first conical surface. The mounting hole 31 has a second conical surface on its inner peripheral wall near the clamping end 11 that fits against the first conical surface. The driving component drives the spring clamp body 1 to move axially. The moving spring clamp body 1 moves axially, causing the spring clamp body 1 to retract and clamp under the action of two conical surfaces; the end face of the clamping end 11 is recessed with a clamping groove 13 for accommodating the piston head; four axially extending partition grooves 14 are also provided on the end face of the clamping end 11, and each partition groove 14 radially penetrates the inner wall and outer wall of the spring clamp body 1; the four partition grooves 14 are evenly distributed along the circumference of the spring clamp body 1, and evenly divide the clamping end 11 to form four clamping arms 10; each clamping arm 10 has a locking part 2 on the clamping end 11 and located outside the locking sleeve 3, and the locking part 2 applies a radial force to the piston head to fix the piston head in the clamping groove 13. This fixture achieves axial positioning of the piston head through the clamping groove 13, ensuring the accuracy of piston head clamping and centering. The multi-lobed clamping arm 10 is formed through the partition groove 14. Relying on the cooperation between the locking sleeve 3 and the conical surface of the spring clamp body 1, the clamping end 11 is radially clamped, completing the initial positioning. In addition, a locking part 2 is added on the basis of the conical surface clamping to provide additional radial locking force, which double-constrains the piston head and overcomes the defect of circumferential slippage between the piston head and the fixture under friction welding conditions of high speed, large friction torque and vibration impact. This avoids welding defects such as discontinuous weld formation, uneven weld thickness and joint malfunction caused by slippage, improves the connection accuracy of the friction welded joint between the piston head and the piston rod, and increases the welding yield.

[0028] like Figures 1 to 4As shown, the locking part 2 includes a locking hole 21 that radially penetrates the clamping arm 10, and a locking member that is radially movable relative to the clamping arm 10 and connected to the locking hole 21. In the locked state, the radial inner end of the locking member abuts against the outer wall of the piston head. By directly pressing the outer wall of the piston head with the radial movement of the locking member, a radial clamping force can be provided independently. This force, combined with the clamping force of the clamping arm 10 from the conical surface, forms a compound clamping force, further resisting the circumferential torque of the friction welding process and providing stronger anti-slip capability. Furthermore, the locking member is radially adjustable, which can adapt to piston head workpieces with a certain outer diameter tolerance range, making it highly adaptable to clamping. The abutment clamping assembly structure is simple and easy to maintain and replace the clamping parts. In this embodiment, the locking hole 21 is a threaded hole, and the locking member is a locking screw that engages with the threaded hole. The locking structure using threaded holes and locking screws is not only simple and inexpensive, but also uses readily available and universal parts. It is easy to adjust and operate, and the screw tightening force can be flexibly adjusted according to the workpiece size and working conditions. Furthermore, the threaded connection has self-locking properties. Under the continuous high-frequency vibration environment of friction welding, the locking screw is not easy to loosen or fall back, and can maintain a stable radial locking force for a long time, which significantly improves clamping reliability and process consistency.

[0029] like Figures 1 to 4 As shown, the spring clip body 1 includes a conical section 101, an inner concave section 102, and an outer circular section 103 arranged sequentially from the clamping end 11 to the connecting end 12. A first conical surface is disposed on the conical section 101, and the diameter of the conical section 101 gradually narrows from the clamping end 11 to the connecting end 12. The outer diameter of the inner concave section 102 is smaller than the minimum outer diameter of the conical section 101 and the outer diameter of the outer circular section 103. By setting the first conical surface on the conical section 101, which cooperates with the second conical surface of the locking sleeve 3, the axial tensile force is converted into a radial clamping force, enabling the clamping arm 10 to reliably retract and clamp the workpiece. The inner concave section 102 is diameter-reduced, forming a stress-avoidance area. When the spring clip body 1 undergoes axial pulling, elastic opening and closing deformation of the clamping arm 10, the deformation is mainly concentrated in the inner concave section 102, reducing residual stress in other parts of the body, improving the fatigue resistance of the spring clip body 1, and extending the service life of the tooling. Furthermore, the concave section 102 has a reduced diameter to allow for deformation space, reducing the risk of plastic deformation when the spring clip body 1 opens and closes, and ensuring the elastic recovery capability of the clamping arm 10 after repeated clamping and releasing.

[0030] like Figures 1 to 4As shown, the conical segment 101 is coaxially connected to an annular segment 104 on the side near the clamping end 11 (left side); the locking hole 21 is radially penetrated through the outer wall of the annular segment 104. The annular segment 104 provides sufficient solid wall thickness for the radial locking hole 21, avoiding a significant decrease in the strength of the clamping arm 10 caused by directly opening a hole in the thin-walled clamping arm 10, thus ensuring the structural strength of the clamping arm 10. Furthermore, the locking screw is positioned in the annular segment 104, away from the stress concentration area at the root of the partition groove 14, so that the opening will not damage the elastic deformation area of ​​the clamping arm 10, balancing the locking installation requirements with the elastic deformation performance of the clamping arm 10. At the same time, the annular segment 104 is close to the workpiece side, and the clamping position of the locking element is close to the piston head clamping position. The clamping force acts directly on the end of the workpiece, with a short lever arm and high clamping efficiency, reducing the risk of workpiece tipping and displacement, and further ensuring alignment accuracy.

[0031] like Figures 1 to 4 As shown, the clamping groove 13 extends axially through the spring clamp body 1, and four radially penetrating stress relief grooves 15 are formed on the outer peripheral wall of the concave section 102. The stress relief grooves 15 are evenly arranged circumferentially along the concave section 102, and each stress relief groove 15 corresponds to a partition groove 14. Each stress relief groove 15 extends axially and connects with the corresponding partition groove 14. Through the connection between the stress relief grooves 15 and the partition grooves 14, when the spring clamp body 1 clamps and opens, the stress can be released through the stress relief grooves 15, reducing the stress concentration caused by clamping deformation and preventing the root of the clamping arm 10 from breaking. This further improves the elasticity of the spring clamp body 1 during repeated opening and closing, reduces the probability of plastic deformation, and improves the durability of the tooling. In addition, the circumferentially evenly arranged stress relief grooves 15 ensure the consistency of deformation of each clamping arm 10, and the uniform shrinkage of the multi-lobed clamping arm 10, improving the coaxiality and centering accuracy of the piston head clamping.

[0032] like Figures 1 to 4 As shown, in this embodiment, the dividing groove 14 extends to the concave section 102 and communicates with the corresponding stress relief groove 15, and the width of the stress relief groove 15 is greater than the width of the dividing groove 14. The wider stress relief groove 15 further releases the deformation stress of the clamping arm 10, improving the stress relief effect. The extension of the dividing groove 14 to the stress relief groove 15 extends the deformation area of ​​the clamping arm 10 to the concave section 102, further enhancing the elasticity of the clamping arm 10, reducing the risk of cracking under clamping load, and improving the fatigue resistance of the tooling.

[0033] like Figures 1 to 4As shown, at least one anti-rotation part is provided on the outer peripheral wall of the concave section 102, and a limiting part corresponding to the anti-rotation part is provided on the locking sleeve 3. The limiting part cooperates with the anti-rotation part to restrict the circumferential rotation of the spring clip body 1 relative to the locking sleeve 3. During friction welding, the spindle torque is transmitted to the spring clip body 1 through the locking sleeve 3. The anti-rotation structure prevents the spring clip body 1 from slipping circumferentially relative to the locking sleeve 3, ensuring that the spindle torque is completely transmitted to the clamped piston head. This further eliminates the relative circumferential rotation between the spring clip body 1 and the locking sleeve 3, reduces internal wear of the tooling, avoids loss of workpiece speed due to slippage of the body, and further ensures the stability of the welding process speed. In this embodiment, the anti-rotation part is an anti-rotation through hole 16 radially opened on the outer wall of the concave section 102. The limiting part includes a mating hole 32 (threaded hole) radially penetrating the locking sleeve 3 and a limiting pin (limiting screw) threadedly engaged with the mating hole 32. The limiting pin passes through the mating hole 32 and is inserted into the anti-rotation through hole 16 to achieve circumferential limitation of the spring clip body 1. The spring clip body 1 is circumferentially locked by the limit pin, mating hole 32 and anti-rotation through hole 16, preventing the spring clip body 1 from moving circumferentially with torque, ensuring the stability of the working position of the whole tooling and making disassembly and assembly convenient.

[0034] In this embodiment, the driving component is a driving rod distributed along the axial direction, and one end of the driving rod is fixedly connected to the connecting end 12 of the spring clip body 1. The driving rod structure is simple and easy to implement.

[0035] The working process of this embodiment is as follows: The spring clamp body 1 is inserted into the locking sleeve 3, and the piston head is inserted into the clamping groove 13 of the spring clamp body 1. A limiting pin is used to circumferentially limit the spring clamp body 1. The drive rod drives the spring clamp body 1 to move axially (to the right). The second conical surface of the locking sleeve 3 presses against the first conical surface of the conical section 101, and the clamping arm 10 elastically contracts, pre-clamping the piston head for centering. Then, each locking screw is tightened so that the inner end of the locking screw abuts against the outer wall of the piston head, completing the secondary locking. Afterward, the friction welding equipment is started, and the machine tool drives the entire tooling and piston head to rotate at high speed. The piston head generates heat through friction with the piston rod end under axial pressure, completing the friction welding process. After processing, the locking screws are loosened to release the pressure from the conical surface, and the processed workpiece can be removed.

[0036] In summary, this fixture achieves initial clamping of the piston head by the conical engagement of the spring clip body 1 and the locking sleeve 3. The additional radial clamping force applied by the locking part 2 creates a double constraint, effectively overcoming the problem of circumferential slippage of the piston head under high-speed, high-torque, and vibration conditions in friction welding. This reduces defects such as weld discontinuity, uneven thickness, and incomplete welding, improving the accuracy and yield of the welded joint. The spring clip body 1 features a concave section 102 with a reduced diameter and a stress-relieving groove 15 connected to the partition groove 14, which can guide and release deformation stress, reduce stress concentration, reduce plastic deformation, and improve the fatigue resistance and service life of the fixture. The locking part 2 is located on the annular section 104, ensuring the structural strength of the clamping arm 10. The clamping position is close to the workpiece, resulting in higher clamping and centering accuracy. An anti-rotation limiting structure consisting of an anti-rotation through hole 16 and a limiting pin is provided between the locking sleeve 3 and the spring clip body 1 to prevent relative circumferential rotation of the fixture body, ensuring complete transmission of spindle torque. The overall design adopts the mature spring clamp assembly method, which can be adapted to existing friction welding machine tools. The workpiece is easy to disassemble and assemble, and the parts are easy to maintain and replace, taking into account both clamping reliability and equipment versatility.

[0037] In the description of the embodiments of this application, it should be noted that the terms "inner" and "outer" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0038] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0039] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A piston head clamping fixture, comprising a cylindrical spring clamp body and a locking sleeve mounted on a machine tool, wherein the locking sleeve has an axially penetrating mounting hole; the spring clamp body is movably inserted axially into the mounting hole, and the two axial ends of the spring clamp body are a connecting end and a clamping end, respectively; the connecting end is connected to a driving component for driving the axial movement of the spring clamp body; the clamping end extends beyond the locking sleeve, characterized in that, The end face of the clamping end is recessed with a clamping groove for accommodating the piston head; the end face of the clamping end is also provided with several axially extending dividing grooves, and each dividing groove radially penetrates the inner wall and outer wall of the spring clamp body; all dividing grooves are evenly distributed along the circumference of the spring clamp body, and the clamping end is evenly divided into several clamping arms; the outer wall of the clamping end of each clamping arm is provided with a first conical surface, and the mounting hole is provided with a second conical surface that mates with the first conical surface on the inner wall near the clamping end. The spring clamp body is driven to move axially by the driving component, so that the clamping arm can be retracted and clamped under the action of the two conical surfaces; a locking part is provided on the clamping end of each clamping arm and on the outside of the locking sleeve. The locking part applies a radial force to the piston head to fix the piston head in the clamping groove.

2. The piston head clamping fixture according to claim 1, characterized in that, The locking part includes a locking hole that extends radially through the clamping arm, and a locking member that is radially movable and connected to the locking hole. In the locked state, the radial inner end of the locking member abuts against the outer wall of the piston head.

3. The piston head clamping fixture according to claim 2, characterized in that, The lock hole is a threaded hole, and the locking component is a locking screw that is threaded into the threaded hole.

4. The piston head clamping fixture according to claim 2, characterized in that, The spring clip body includes a conical segment, an inner concave segment, and an outer circular segment arranged sequentially from the clamping end to the connecting end; the first conical surface is disposed on the conical segment, and the diameter of the conical segment gradually narrows from the clamping end to the connecting end; the outer diameter of the inner concave segment is smaller than the minimum outer diameter of the conical segment and the outer diameter of the outer circular segment.

5. The piston head clamping fixture according to claim 4, characterized in that, The conical section is coaxially connected to an annular section on the side near the clamping end; the locking hole is radially opened through the outer wall of the annular section.

6. The piston head clamping fixture according to claim 4, characterized in that, The clamping groove extends axially through the spring clamp body, and the outer peripheral wall of the concave section is provided with a plurality of stress relief grooves extending radially through; the stress relief grooves are evenly arranged circumferentially along the concave section, and the stress relief grooves correspond one-to-one with the partition grooves, and each stress relief groove extends axially and communicates with the corresponding partition groove.

7. The piston head clamping fixture according to claim 6, characterized in that, The dividing groove extends into the concave section and communicates with the corresponding stress relief groove, and the width of the stress relief groove is greater than the width of the dividing groove.

8. The piston head clamping fixture according to claim 4 or 6, characterized in that, At least one anti-rotation part is provided on the outer peripheral wall of the concave section, and a limiting part corresponding to the anti-rotation part is provided on the locking sleeve. The limiting part cooperates with the anti-rotation part to restrict the circumferential rotation of the spring clip body relative to the locking sleeve.

9. The piston head clamping fixture according to claim 8, characterized in that, The anti-rotation part is an anti-rotation through hole radially opened on the outer wall of the concave section. The limiting part includes a mating hole radially penetrating the lock sleeve and a limiting pin threaded with the mating hole. The limiting pin passes through the mating hole and is inserted into the anti-rotation through hole to achieve circumferential limiting of the spring clip body.

10. The piston head clamping fixture according to claim 1, characterized in that, The driving component is a driving rod distributed along the axial direction, and one end of the driving rod is fixedly connected to the connecting end of the spring clip body.

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