A special-shaped piston pin surface precision machining positioning tool device and positioning method

Abstract

The application provides a special-shaped piston pin surface precision machining positioning tool device and positioning method, and relates to the field of piston pin machining.The device comprises a clamp base, a piston pin insertion pipe is fixedly connected to the front of the clamp base, a first wedge surface push block, a second wedge surface push block and a third wedge surface push block are sequentially arranged in the piston pin insertion pipe from front to back, and the three wedge surface push blocks are all four-pyramid structures;first, second and third wedge surface push blocks are sequentially arranged in the piston pin insertion pipe along the axial direction, and are matched with self-adaptive expansion wedge blocks to construct three groups of independently controllable inner support driving units, wherein the push block connecting rod, the second traction rod and the third traction rod are independently elastically pulled by three linkage springs at the front end of the linkage pull plate, so that the axial displacement of each wedge surface push block can be adjusted according to the actual profile of the special-shaped piston pin inner hole, thereby realizing the differential control of the expansion amount of the self-adaptive expansion wedge blocks at different axial positions.

Description

Technical Field

[0001] This invention relates to the field of piston pin machining technology, and in particular to a precision machining and positioning fixture and method for irregularly shaped piston pin surfaces. Background Technology

[0002] As a key transmission component in an engine, the piston pin transmits the gas pressure from the piston to the connecting rod mechanism. With the continuous improvement of engine power density and reliability, the alternating stress and local stress concentration in the piston pin bore area have become increasingly prominent. To improve this situation, engineers have further modified the piston pin and designed a special-shaped piston pin. By adjusting the cross-sectional profile of the inner hole in the axial direction, the wall thickness distribution and load distribution are made more consistent. Different structural stiffness is provided according to the stress state of different cross sections, which alleviates the stress concentration phenomenon under high load conditions, improves the overall load-bearing capacity and fatigue resistance of the piston pin assembly, and takes into account the engineering requirements of lightweight and high strength. It is increasingly widely used in the fields of high-performance automotive engines and high-power diesel engines.

[0003] For precision machining processes such as local grinding and polishing of the outer cylindrical surface of irregular piston pins, traditional fixtures often adopt a rigid clamping method that covers the outer cylindrical surface. The jaws are in direct contact with the workpiece surface, which can easily cause secondary damage such as indentations and scratches to the already machined surface during the machining process. Although the problem of damage to the outer surface can be avoided by adopting an internal support clamping scheme, the internal hole structure of irregular piston pins is non-cylindrical and the cross-sectional profile is varied. Conventional internal support mechanisms are difficult to achieve conformal fit and reliable support for irregular contours, resulting in insufficient workpiece positioning rigidity. Under the action of polishing force and rotational centrifugal force, slight vibration or axial runout is easily generated, which in turn introduces additional shape errors and surface quality fluctuations, restricting further improvement of machining accuracy. Summary of the Invention

[0004] This invention provides a precision machining positioning fixture and method for irregularly shaped piston pins, which solves the problem that conventional internal support mechanisms are difficult to achieve conformal fitting and reliable support for irregular contours, resulting in insufficient workpiece positioning rigidity. Under the action of polishing force and rotational centrifugal force, slight vibration or axial runout is easily generated, which in turn introduces additional shape errors and surface quality fluctuations, thus restricting further improvement of machining accuracy.

[0005] This invention provides a precision machining and positioning fixture and method for irregularly shaped piston pins. Specifically, it includes: a fixture base; a piston pin insertion tube fixedly connected to the front of the fixture base; a first wedge-shaped pusher block, a second wedge-shaped pusher block, and a third wedge-shaped pusher block arranged slidably from front to back within the insertion tube guide hole of the piston pin insertion tube; all three wedge-shaped pusher blocks are four-sided pyramidal structures, and adaptive expanding wedge blocks are slidably connected to the four inclined surfaces of each wedge-shaped pusher block. The adaptive expanding wedge blocks are slidably connected to through holes in the pipe wall of the piston pin insertion tube. A pusher block connecting rod is fixedly connected to the rear end of the first wedge-shaped pusher block; a second pusher block connecting tube is fixedly connected to the rear of the second wedge-shaped pusher block, and the second pusher block connecting tube is slidably connected to the pusher block connecting rod. The rod slides through the second wedge-shaped push block. A third push block connecting tube is fixedly connected to the rear of the third wedge-shaped push block. The third push block connecting tube is slidably connected to the second push block connecting tube. The second push block connecting tube slides through the third wedge-shaped push block. A second traction rod is fixedly connected to the lower rear edge of the second push block connecting tube. A third traction rod is fixedly connected to the upper rear edge of the third push block connecting tube. An adaptive locking frame is slidably connected to the rear of the clamp base. An adaptive adjusting push cylinder is fixedly installed at the rear end of the adaptive locking frame via a bracket. A linkage pull plate is fixedly connected to the front end of the push rod of the adaptive adjusting push cylinder. Three linkage tension springs are fixedly connected to the front end of the linkage pull plate. The front ends of the three linkage tension springs are respectively fixedly connected to the rear ends of the push block connecting rod, the second traction rod, and the third traction rod.

[0006] Furthermore, the first wedge push block is fixedly connected to a first inclined guide rod with a "T" shaped cross-section, the second wedge push block is fixedly connected to a second inclined guide rod with a "T" shaped cross-section, and the third wedge push block is fixedly connected to a third inclined guide rod with a "T" shaped cross-section. The adaptive expansion wedge block has a wedge block groove with a "T" shaped cross-section on its inclined surface facing the piston pin insertion tube, and the wedge block groove is slidably connected to the inclined guide rod.

[0007] Furthermore, a wedge support head is fixedly connected to the side of the adaptive expansion wedge block away from the piston pin insertion tube axis.

[0008] Furthermore, two base guide rods are fixedly connected to the rear of the clamp base, and a lock frame guide hole is opened on the top of the adaptive lock frame, with the base guide rods slidably connected to the lock frame guide hole.

[0009] Furthermore, a lock frame push plate is fixedly connected to the rear edge of the lower surface of the adaptive lock frame, and a locking push cylinder is fixedly connected to the rear of the clamp base, with the rear end of the push rod of the locking push cylinder fixedly connected to the lock frame push plate.

[0010] Furthermore, a fixed-distance push cylinder is fixedly connected to the left and right surfaces of the adaptive lock frame, and a fixed-distance clamping plate is fixedly connected to the push rod of the fixed-distance push cylinder. The fixed-distance clamping plate is located inside the adaptive lock frame, and a clamping plate guide rod is fixedly connected to the outer end of the fixed-distance clamping plate. The clamping plate guide rod is slidably connected to the side wall of the adaptive lock frame.

[0011] Furthermore, three clamping plate synchronous locking blocks are fixedly connected to the side of the fixed-distance clamping plate facing the center of the adaptive locking frame. The three clamping plate synchronous locking blocks respectively fit into the push block connecting rod, the second push block connecting tube and the third push block connecting tube.

[0012] Furthermore, the rear end face of the push block connecting rod is provided with a connecting rod guide hole, the rear end of the second traction rod is provided with a second traction guide hole, and the rear end of the third traction rod is provided with a third traction guide hole.

[0013] Furthermore, three linkage rods are vertically welded to the front surface of the linkage plate, and the three linkage rods are respectively slidably connected to the connecting rod guide hole, the second traction guide hole and the third traction guide hole.

[0014] Furthermore, the positioning method includes the following steps: 01. The irregular piston pin is sleeved on the outer periphery of the piston pin insertion tube, so that the axial positions of the three sets of adaptive expansion wedges correspond to different cross-sectional areas of the piston pin inner hole.

[0015] 02. When clamping and starting, the push rod of the adaptive adjustment push cylinder retracts backward, driving the linkage pull plate and the three linkage tension springs to move backward synchronously. The linkage tension springs pull the push block connecting rod, the second traction rod and the third traction rod respectively. The push block connecting rod directly pulls the first wedge push block. The second traction rod pulls the second wedge push block through the second push block connecting tube. The third traction rod pulls the third wedge push block through the third push block connecting tube. The three sets of wedge push blocks generate axial displacement backward in the insertion tube guide hole. The three form a layer-by-layer sliding nested structure from the inside to the outside. The axial displacement of each wedge push block does not interfere with each other.

[0016] 03. When the wedge pusher moves backward, its quadrangular pyramidal structure's inclined surface, through the first, second, and third inclined guide rods, interlocks with the wedge block's sliding groove in a "T" shape, pushing the corresponding four adaptive expansion wedge blocks to slide outward along the tube wall perforation radially. The wedge block support head simultaneously presses against the inner wall of the piston pin's bore from four circumferential directions. The linkage spring provides elastic buffering, allowing each wedge pusher to adjust its axial displacement according to the actual profile of its inner hole, thereby automatically adapting to the contours of irregular inner holes such as flared or non-circular curved surfaces, achieving multi-point conformal expansion, and ensuring that the axis of the piston pin's inner hole is coaxial with the axis of the piston pin insertion tube.

[0017] 04. After the conformal tensioning is completed, the fixed-distance push cylinders on both sides of the self-adaptive locking frame are controlled to push the fixed-distance clamping plates to move towards each other. The three clamping plates synchronously lock the outer surfaces of the push block connecting rod, the second push block connecting tube and the third push block connecting tube respectively, and synchronously lock the axial positions of the three sets of wedge push blocks.

[0018] 05. Control the locking push cylinder action. The push rod of the locking push cylinder drives the adaptive locking frame to apply a thrust backward along the base guide rod. The adaptive locking frame applies a backward overall pulling force to the three locked traction components through the clamping plate synchronous locking block, further strengthening the radial expansion force of the adaptive expansion wedge block on the piston pin inner hole, ensuring that the piston pin is positioned on the piston pin insertion tube with high rigidity and high stability during the processing.

[0019] This invention provides a precision machining and positioning fixture and method for irregularly shaped piston pin surfaces, which has the following advantages: This invention constructs three independently adjustable internal support drive units by sequentially arranging a first wedge-shaped pusher, a second wedge-shaped pusher, and a third wedge-shaped pusher along the axial direction inside the piston pin insertion tube, in conjunction with an adaptive expansion wedge. The pusher connecting rod, the second traction rod, and the third traction rod are each independently elastically pulled by three linkage springs at the front end of the linkage pull plate. This allows the axial displacement of each wedge-shaped pusher to be adjusted according to the actual profile of the irregular piston pin's inner hole, thereby achieving differentiated control of the adaptive expansion wedge's tension at different axial positions. The adaptive expansion wedge forms an inclined plane slide with the inclined guide rod on each wedge-shaped pusher through a wedge sliding groove. The dynamic engagement smoothly converts axial push-pull force into radial tension displacement. The wedge block head abuts against the wall of the irregular inner hole with multi-point discrete contact, effectively adapting to irregular inner hole contours such as flared and non-circular curved surfaces. Compared with the traditional rigid clamping method, this internal support structure avoids direct contact clamping on the outer surface of the piston pin, eliminating the risk of secondary damage such as scratches and indentations on the outer surface. It is especially suitable for processing procedures with strict surface quality requirements, such as precision polishing of the outer circle and local grinding. The linkage spring is connected in series between the traction rod and the linkage pull plate, providing flexible compensation during the clamping process, which can buffer the local stress concentration caused by the irregular inner hole contour.

[0020] Furthermore, regarding the position locking after tensioning and shaping, this device is equipped with an adaptive locking frame behind the fixture base. The fixed-distance push cylinders on both sides of the adaptive locking frame push the fixed-distance clamping plate and the clamping plate synchronous locking block to synchronously clamp and lock the push block connecting rod, the second push block connecting tube, and the third push block connecting tube. This ensures that the axial position of each wedge push block remains stable throughout the entire processing, avoiding the tension shrinkage caused by pressure fluctuations of the adaptive adjustment push cylinder or mechanical vibration. This significantly improves the repeatability and consistency of the clamping. After synchronously clamping and locking the push block connecting rod, the second push block connecting tube, and the third push block connecting tube, the locking push cylinder drives the entire locking frame to slide axially along the base guide rod, applying a backward thrust to the three sets of wedge push blocks inside the piston pin insertion tube. This strengthens the expansion force of the adaptive expansion wedge blocks on the piston pin, thereby further enhancing the positioning strength of the irregular piston pin. In summary, the device of the present invention has the ability to conform to the shape of irregular inner holes, the characteristics of non-destructive clamping of outer surfaces, and the function of maintaining high rigidity during the processing. It can effectively improve the positioning accuracy in the precision machining of irregular piston pins, improve the quality of finished products, and adapt to the rapid fixing of irregular piston pins with different inner hole structures. It can be used for the processing of various types and small batches of irregular piston pins. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0022] The accompanying drawings described below are only related to some embodiments of the invention and are not intended to limit the invention.

[0023] In the attached diagram: Figure 1 A schematic diagram of the overall structure of this application is shown; Figure 2 This paper shows a schematic diagram of the internal structure of the piston pin insertion tube of this application; Figure 3 This application shows Figure 2 A structural diagram from the right perspective; Figure 4 This application shows Figure 2 A schematic diagram of the right-side view structure; Figure 5 This paper shows a schematic diagram of the internal structure of the adaptive locking frame after dissection. Figure 6 A schematic diagram of the structure of the fixed-distance clamping plate of this application is shown; Figure 7 This diagram shows the structure of the first wedge-shaped pusher block, the second wedge-shaped pusher block, and the third wedge-shaped pusher block when they are engaged. Figure 8 This diagram shows the structure of the first wedge-shaped pusher, the second wedge-shaped pusher, and the third wedge-shaped pusher when they are separated. Figure 9This invention provides a schematic diagram of the structure for fixing an irregularly shaped piston pin with multi-directional inward support. Figure 10 A schematic diagram of the structure of the clamping plate synchronization lock block of this application is shown; Figure 11 This application shows Figure 5 A magnified structural diagram of point A in the middle.

[0024] Figure label: 1. Fixture base; 101. Base guide rod; 2. Piston pin insertion tube; 201. Insertion tube guide hole; 202. Tube wall perforation; 3. First wedge-shaped push block; 301. First inclined guide rod; 302. Push block connecting rod; 303. Connecting rod guide hole; 4. Second wedge-shaped push block; 401. Second inclined guide rod; 402. Second push block connecting tube; 403. Second traction rod; 404. Second traction guide hole; 5. Third wedge-shaped push block; 501. Third inclined guide rod; 502. Third push block 503. Connecting pipe; 504. Third traction rod; 505. Third traction guide hole; 6. Adaptive expansion wedge block; 606. Wedge block groove; 607. Wedge block support head; 708. Adaptive locking frame; 709. Fixed distance push cylinder; 700. Fixed distance clamping plate; 700. Clamping plate guide rod; 700. Clamping plate synchronous locking block; 700. Locking frame guide hole; 701. Locking frame push plate; 8. Locking push cylinder; 902. Adaptive adjustment push cylinder; 903. Linkage pull plate; 904. Linkage pull rod; 905. Linkage tension spring. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1: Please refer to Figures 1 to 11 : This invention proposes a precision machining and positioning fixture and method for irregularly shaped piston pins, comprising: a fixture base 1, a piston pin insertion tube 2 fixedly connected to the front of the fixture base 1, and a first wedge-shaped pusher block 3, a second wedge-shaped pusher block 4, and a third wedge-shaped pusher block 5 arranged and slidably connected from front to back in the insertion tube guide hole 201 inside the piston pin insertion tube 2. All three wedge-shaped pushers are quadrangular pyramidal structures, and adaptive expansion wedge blocks 6 are slidably connected to the four inclined surfaces of each wedge-shaped pusher block. The expansion wedge 6 is slidably connected to the through hole 202 in the pipe wall of the piston pin insertion tube 2. A pusher rod 302 is fixedly connected to the rear end of the first wedge pusher 3. A second pusher connecting tube 402 is fixedly connected to the rear end of the second wedge pusher 4. The second pusher connecting tube 402 is slidably connected to the pusher connecting rod 302, and the pusher connecting rod 302 slides through the second wedge pusher 4. A third pusher connecting tube 502 is fixedly connected to the rear end of the third wedge pusher 5. 2. The second push block connecting pipe 402 is slidably connected, and the second push block connecting pipe 402 slides through the third wedge surface push block 5. The lower rear end edge of the second push block connecting pipe 402 is fixedly connected to the second traction rod 403, and the upper rear end edge of the third push block connecting pipe 502 is fixedly connected to the third traction rod 503. The self-adaptive locking frame 7 is slidably connected to the rear of the clamp base 1. The self-adaptive adjusting push cylinder 9 is fixedly installed at the rear end of the self-adaptive locking frame 7 through the bracket. The front end of the push rod of the self-adaptive adjusting push cylinder 9 is fixedly connected to the linkage pull plate 901. The front end of the linkage pull plate 901 is fixedly connected to three linkage tension springs 903. The front ends of the three linkage tension springs 903 are respectively fixedly connected to the rear ends of the push block connecting rod 302, the second traction rod 403 and the third traction rod 503. The push block connecting rod 302 passes through the second wedge surface push block 4, and the second push block connecting pipe 402 passes through the third wedge surface push block 5. The three form a layer-by-layer sliding nesting relationship from the inside to the outside, so that the axial displacement of each wedge surface push block does not interfere with each other. The adaptive adjustment push cylinder 9 synchronously pulls three linkage springs 903 through the linkage pull plate 901, which then act on the push block connecting rod 302, the second traction rod 403 and the third traction rod 503 respectively. The function of the linkage spring 903 is to provide elastic buffer during the tensioning process, so that each wedge push block can adjust its axial displacement according to the actual profile of its inner hole, and achieve conformal tensioning.

[0027] In this embodiment, the inclined surface of the first wedge pusher 3 is fixedly connected to a first inclined guide rod 301 with a "T" shaped cross-section, the inclined surface of the second wedge pusher 4 is fixedly connected to a second inclined guide rod 401 with a "T" shaped cross-section, and the inclined surface of the third wedge pusher 5 is fixedly connected to a third inclined guide rod 501 with a "T" shaped cross-section. The inclined surface of the adaptive expansion wedge 6 facing the piston pin insertion tube 2 is provided with a wedge groove 601 with a "T" shaped cross-section. The wedge groove 601 is slidably connected to the inclined guide rod. The side of the adaptive expansion wedge 6 away from the axis of the piston pin insertion tube 2 is fixedly connected to a wedge support head 602. The first inclined guide rod 301, the second inclined guide rod 401 and the third inclined guide rod 501 all adopt a "T" shaped cross-section structure, forming an interlocking sliding fit with the wedge groove 601, which can effectively prevent the adaptive expansion wedge 6 from dislodging from the inclined surface during the radial expansion process, ensuring the reliability and synchronicity of the expansion action. Four adaptive expansion wedges 6 are evenly distributed around the outer circumference of the same wedge-shaped pusher. When the wedge-shaped pusher moves towards the rear end of the piston pin insertion tube 2 under axial tension, its inclined surface pushes the adaptive expansion wedges 6 to slide radially outward along the tube wall perforation 202. The wedge support heads 602 simultaneously abut against the inner wall of the piston pin bore from four directions. This four-point synchronous tensioning structure not only provides a stable radial clamping force but also ensures the coaxiality of the piston pin inner bore axis and the piston pin insertion tube 2 axis, providing an accurate rotational reference for subsequent precision machining of the outer diameter.

[0028] In this embodiment, a fixed-distance push cylinder 701 is fixedly connected to the left and right surfaces of the adaptive locking frame 7, respectively. A fixed-distance clamping plate 702 is fixedly connected to the push rod of the fixed-distance push cylinder 701. The fixed-distance clamping plate 702 is located inside the adaptive locking frame 7. A clamping plate guide rod 703 is fixedly connected to the outer end of the fixed-distance clamping plate 702. The clamping plate guide rod 703 is slidably connected to the side wall of the adaptive locking frame 7. Three clamping plate synchronous locking blocks 704 are fixedly connected to the side of the fixed-distance clamping plate 702 facing the center of the adaptive locking frame 7. The three clamping plate synchronous locking blocks 704 respectively abut against the push block connecting rod 302 and the second push block connecting tube 40. 2 and the third push block connecting pipe 502; the two side fixed distance push cylinders 701 push the fixed distance clamping plate 702 to move towards each other, so that the three clamping plates synchronous locking blocks 704 respectively press the outer surfaces of the push block connecting rod 302, the second push block connecting pipe 402 and the third push block connecting pipe 502, and synchronously lock the axial position of each wedge push block after completing the conformal tensioning, so as to prevent the tension from shrinking due to the pressure fluctuation of the push cylinder or mechanical vibration during the processing. By applying force synchronously by the double side clamping plates, the radial wobble of each push block connecting rod due to unidirectional force is avoided, which further improves the overall rigidity and repeatability of the clamping system.

[0029] In this embodiment, two base guide rods 101 are fixedly connected to the rear of the clamp base 1. A lock frame guide hole 705 is opened at the top of the adaptive lock frame 7. The base guide rod 101 is slidably connected to the lock frame guide hole 705. A lock frame push plate 706 is fixedly connected to the rear edge of the lower surface of the adaptive lock frame 7. A locking push cylinder 8 is fixedly connected to the rear of the clamp base 1. The rear end of the push rod of the locking push cylinder 8 is fixedly connected to the lock frame push plate 706. After the push block connecting rod 302, the second push block connecting tube 402 and the third push block connecting tube 502 are synchronously clamped and locked, the locking push cylinder 8 drives the entire lock frame to slide axially along the base guide rod 101, and applies a rear thrust to the three sets of wedge push blocks inside the piston pin insertion tube 2, thereby strengthening the expansion force of the adaptive expansion wedge block 6 on the piston pin, making up for the deficiency of insufficient tension of the linkage spring 903, and strengthening the positioning strength of the irregular piston pin.

[0030] In Example 2, based on Example 1, a connecting rod guide hole 303 is provided on the rear end face of the push block connecting rod 302, a second traction guide hole 404 is provided at the rear end fold of the second traction rod 403, and a third traction guide hole 504 is provided at the rear end fold of the third traction rod 503. Three linkage pull rods 902 are vertically welded to the front surface of the linkage pull plate 901. The three linkage pull rods 902 are slidably connected to the connecting rod guide hole 303, the second traction guide hole 404 and the third traction guide hole 504 respectively, which play a guiding role and ensure the angular accuracy of the first wedge push block 3, the second wedge push block 4 and the third wedge push block 5.

[0031] The working principle of this embodiment is as follows: Before clamping, the irregularly shaped piston pin is first fitted onto the outer periphery of the piston pin insertion tube 2, so that the axial positions of the three sets of adaptive expansion wedges 6 correspond to different cross-sectional areas of the piston pin inner hole. When clamping is started, the push rod of the adaptive adjustment push cylinder 9 retracts backward, driving the linkage pull plate 901 and the three linkage tension springs 903 to move backward synchronously. The linkage tension springs 903 respectively pull the push block connecting rod 302, the second traction rod 403 and the third traction rod 503. Among them, the push block connecting rod 302 directly pulls the first wedge push block 3, the second traction rod 403 pulls the second wedge push block 4 through the second push block connecting tube 402, and the third traction rod 503 pulls the third wedge push block 5 through the third push block connecting tube 502. The three sets of wedge push blocks generate a backward axial displacement in the insertion tube guide hole 201. Because the pusher connecting rod 302 slides through the second wedge-shaped pusher 4 and the second pusher connecting tube 402 slides through the third wedge-shaped pusher 5, the three form a layered sliding nested structure from the inside out, and the axial displacement of each wedge-shaped pusher does not interfere with each other. When the wedge-shaped pusher moves backward, its quadrangular pyramidal structure's inclined surface, through the "T"-shaped interlocking cooperation between the first inclined guide rod 301, the second inclined guide rod 401, and the third inclined guide rod 501 and the wedge-shaped sliding groove 601, pushes the corresponding four self-adaptive expansion wedges 6 to slide radially outward along the tube wall perforation 202, and the wedge support head 602 simultaneously presses against the inner hole wall of the piston pin from four circumferential directions. During this process, the linkage spring 903 provides elastic buffering, allowing each wedge-shaped pusher to adjust its axial displacement according to the actual profile of the inner hole at its position, thereby automatically adapting to the contours of irregular inner holes such as flared and non-circular curved surfaces, achieving multi-point conformal expansion, and ensuring that the axis of the piston pin inner hole is coaxial with the axis of the piston pin insertion tube 2. After the conformal tensioning is completed, the fixed-distance push cylinders 701 on both sides of the adaptive locking frame 7 push the fixed-distance clamping plates 702 to move towards each other. The three clamping plates synchronous locking blocks 704 respectively press the outer surfaces of the push block connecting rod 302, the second push block connecting tube 402, and the third push block connecting tube 502, locking the axial positions of the three sets of wedge-shaped push blocks synchronously. Subsequently, the push rod of the locking push cylinder 8 drives the adaptive locking frame 7 as a whole to apply a thrust backward along the base guide rod 101. The adaptive locking frame 7 applies a backward overall pulling force to the three locked traction components through the clamping plate synchronous locking blocks 704, further strengthening the radial expansion force of the adaptive expansion wedge block 6 on the inner hole of the piston pin, effectively supplementing the insufficient tension force that may exist when the linkage spring 903 elastically pulls, and ensuring that the piston pin is positioned on the piston pin insertion tube 2 with high rigidity and high stability during the processing.

[0032] The following points should be noted in this article: 1. The accompanying drawings of the embodiments disclosed herein only relate to the structures involved in the embodiments disclosed herein; other structures can be referred to in a general design.

[0033] 2. Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0034] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A precision machining and positioning fixture for irregularly shaped piston pins, comprising: A clamp base (1) is characterized in that a piston pin insertion tube (2) is fixedly connected to the front of the clamp base (1). A first wedge-shaped pusher (3), a second wedge-shaped pusher (4), and a third wedge-shaped pusher (5) are slidably connected from front to back in the insertion tube guide hole (201) inside the piston pin insertion tube (2). The three wedge-shaped pushers are all four-sided pyramidal structures, and adaptive expansion wedges (6) are slidably connected to the four inclined surfaces of the wedge-shaped pushers. The adaptive expansion wedges (6) are slidably connected to the tube wall through hole (202) opened in the tube wall of the piston pin insertion tube (2). A pusher connecting rod (302) is fixedly connected to the rear end of the first wedge-shaped pusher (3). A second pusher connecting tube (402) is fixedly connected to the rear end of the second wedge-shaped pusher (4). The second pusher connecting tube (402) is slidably connected to the pusher connecting rod (302), and the pusher connecting rod (302) slidably passes through the second wedge-shaped pusher (4). The third wedge-shaped pusher (5) is fixedly connected to the rear end of the third wedge-shaped pusher (5). A third push block connecting pipe (502) is fixedly connected, and the third push block connecting pipe (502) is slidably connected to the second push block connecting pipe (402). The second push block connecting pipe (402) slidably passes through the third wedge-shaped push block (5). The lower rear end of the second push block connecting pipe (402) is fixedly connected to the second traction rod (403). The upper rear end of the third push block connecting pipe (502) is fixedly connected to the third traction rod (503). An adaptive locking frame (7) is slidably connected behind the clamp base (1). An adaptive adjusting push cylinder (9) is fixedly installed at the rear end of the adaptive locking frame (7) through a bracket. The front end of the push rod of the adaptive adjusting push cylinder (9) is fixedly connected to a linkage pull plate (901). The front end of the linkage pull plate (901) is fixedly connected to three linkage tension springs (903). The front ends of the three linkage tension springs (903) are respectively fixedly connected to the rear ends of the push block connecting rod (302), the second traction rod (403), and the third traction rod (503).

2. The precision machining and positioning fixture for irregularly shaped piston pins according to claim 1, characterized in that, The first wedge push block (3) is fixedly connected to a first inclined guide rod (301) with a "T" shaped cross section on its inclined surface. The second wedge push block (4) is fixedly connected to a second inclined guide rod (401) with a "T" shaped cross section on its inclined surface. The third wedge push block (5) is fixedly connected to a third inclined guide rod (501) with a "T" shaped cross section on its inclined surface. The adaptive expansion wedge block (6) has a wedge block groove (601) with a "T" shaped cross section on its inclined surface facing the piston pin insertion tube (2). The wedge block groove (601) is slidably connected to the inclined guide rod.

3. The precision machining and positioning fixture for irregularly shaped piston pins according to claim 1, characterized in that, The side of the adaptive expansion wedge (6) away from the axis of the piston pin insertion tube (2) is fixedly connected to a wedge support head (602).

4. The precision machining and positioning fixture for irregularly shaped piston pins according to claim 1, characterized in that, Two base guide rods (101) are fixedly connected to the rear of the clamp base (1), and a lock frame guide hole (705) is opened on the top of the adaptive lock frame (7), and the lock frame guide hole (705) is slidably connected to the base guide rod (101).

5. The precision machining and positioning fixture for irregularly shaped piston pins according to claim 1, characterized in that, The rear edge of the lower surface of the adaptive lock frame (7) is fixedly connected to a lock frame push plate (706), and the rear of the clamp base (1) is fixedly connected to a locking push cylinder (8), and the rear end of the push rod of the locking push cylinder (8) is fixedly connected to the lock frame push plate (706).

6. The precision machining and positioning fixture for irregularly shaped piston pins according to claim 1, characterized in that, The adaptive lock frame (7) has fixed distance push cylinders (701) on its left and right surfaces respectively. The push rod of the fixed distance push cylinder (701) is fixedly connected to a fixed distance clamping plate (702). The fixed distance clamping plate (702) is located inside the adaptive lock frame (7). The outer end of the fixed distance clamping plate (702) is fixedly connected to a clamping plate guide rod (703). The clamping plate guide rod (703) is slidably connected to the side wall of the adaptive lock frame (7).

7. The precision machining and positioning fixture for irregularly shaped piston pins according to claim 6, characterized in that, Three clamping plate synchronous locking blocks (704) are fixedly connected to the side of the fixed-distance clamping plate (702) facing the center of the adaptive locking frame (7). The three clamping plate synchronous locking blocks (704) respectively attach to the push block connecting rod (302), the second push block connecting tube (402) and the third push block connecting tube (502).

8. The precision machining and positioning fixture for irregularly shaped piston pins according to claim 1, characterized in that, The rear end face of the push block connecting rod (302) is provided with a connecting rod guide hole (303), the rear end of the second traction rod (403) is provided with a second traction guide hole (404), and the rear end of the third traction rod (503) is provided with a third traction guide hole (504).

9. A precision machining and positioning fixture for irregularly shaped piston pins according to claim 8, characterized in that, The front surface of the linkage plate (901) is vertically welded with three linkage rods (902), and the three linkage rods (902) are respectively slidably connected to the connecting rod guide hole (303), the second traction guide hole (404) and the third traction guide hole (504).

10. The positioning method of a precision machining positioning fixture for irregularly shaped piston pins according to any one of claims 1-9, characterized in that, Includes the following steps:

01. The irregular piston pin is sleeved on the outer periphery of the piston pin insertion tube (2), so that the axial positions of the three sets of adaptive expansion wedges (6) correspond to different cross-sectional areas of the piston pin inner hole; 02. When clamping is started, the push rod of the adaptive adjustment push cylinder (9) retracts backward, driving the linkage pull plate (901) and the three linkage springs (903) to move backward synchronously. The linkage springs (903) pull the push block connecting rod (302), the second traction rod (403) and the third traction rod (503) respectively. The push block connecting rod (302) directly pulls the first wedge push block (3), the second traction rod (403) pulls the second wedge push block (4) through the second push block connecting pipe (402), and the third traction rod (503) pulls the third wedge push block (5) through the third push block connecting pipe (502). The three sets of wedge push blocks generate axial displacement backward in the insertion tube guide hole (201). The three form a layer-by-layer sliding nested structure from the inside to the outside. The axial displacement of each wedge push block does not interfere with each other.

03. When the wedge pusher moves backward, the inclined surface of its four-sided pyramid structure is interlocked with the wedge slide groove (601) through the first inclined guide rod (301), the second inclined guide rod (401) and the third inclined guide rod (501) in a "T" shape, pushing the four corresponding adaptive expansion wedges (6) to slide outward radially along the pipe wall perforation (202). The wedge support head (602) simultaneously presses against the inner hole wall of the piston pin from four circumferential directions. The linkage spring (903) provides elastic buffer, so that each wedge pusher can adjust its axial displacement according to the actual profile of the inner hole at its position, thereby automatically adapting to the profile of the horn-shaped, non-circular curved, and other irregular inner holes, realizing multi-point conformal expansion, and ensuring that the axis of the inner hole of the piston pin is coaxial with the axis of the piston pin insertion tube (2).

04. After the conformal tensioning is completed, the fixed-distance push cylinders (701) on both sides of the adaptive locking frame (7) are controlled to push the fixed-distance clamping plates (702) to move towards each other. The three clamping plates synchronous locking blocks (704) press the outer surfaces of the push block connecting rod (302), the second push block connecting pipe (402) and the third push block connecting pipe (502) respectively, and lock the axial position of the three sets of wedge push blocks synchronously.

05. Control the locking push cylinder (8) to move. The push rod of the locking push cylinder (8) drives the adaptive lock frame (7) to apply a push force backward along the base guide rod (101). The adaptive lock frame (7) applies a backward overall pulling force to the three locked traction components through the clamping plate synchronous locking block (704), further strengthening the radial expansion force of the adaptive expansion wedge block (6) on the piston pin inner hole. At this point, the piston pin is positioned on the piston pin insertion tube (2).

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