A gear shaft riveting fixture

Abstract

This utility model discloses a gear shaft riveting fixture, belonging to the field of riveting technology, comprising: a positioning base having a positioning hole for placing the gear shaft and a bearing surface for placing a base plate; when the gear shaft is placed in the positioning hole and the base plate is placed on the bearing surface, the riveting section penetrates the first through hole, and the embedded groove is located in the first through hole; a movable part, arranged opposite to the positioning base and capable of moving relative to the positioning base between a first position and a second position; a ejector pin, mounted on the movable part and coaxially arranged with the positioning hole; the end of the ejector pin has an annular protrusion, the inner diameter of which is slightly larger than the outer diameter of the riveting section; the riveting fixture adopts a base plate deformation method, that is, the annular protrusion squeezes the base plate to make its deformed part embed into the gear shaft embedded groove to form a locking structure; there will be no uneven protrusions on the back of the riveted base plate, and the flatness of this riveting method is greatly improved compared with the prior art.

Description

Technical Field

[0001] This utility model relates to the field of riveting technology, and in particular to a gear shaft riveting fixture. Background Technology

[0002] Air valve actuators have a wide range of applications and are in high demand. They contain a gear transmission system, and the gear fixing shaft is essential. The gear shaft needs to be riveted to the base plate on the air valve actuator housing for fixation to prevent gear wobbling. In order to meet the process requirements and improve efficiency, a gear shaft riveting fixture is designed.

[0003] Currently, in the industry, the riveting of gear shafts to base plates typically involves deforming the gear shaft end: the exposed end of the gear shaft is directly pressed by a punch to induce radial plastic deformation (such as flanging), forming a mechanical lock with the through hole in the base plate. However, in this traditional process, the gear shaft is prone to bending after being subjected to axial impact force, leading to abnormal noise and jamming during subsequent transmission.

[0004] Therefore, for the existing gear shaft riveting process, it is necessary to develop a new riveting fixture that replaces the gear shaft deformation with the deformation of the base plate. Utility Model Content

[0005] This utility model provides a gear shaft riveting fixture to solve the problems in the prior art.

[0006] The technical solution adopted in this embodiment of the utility model is as follows: A gear shaft riveting fixture is used to rivet a gear shaft to a base plate. The gear shaft has a riveting section at one end and an embedded groove formed on the outer peripheral wall of the riveting section. A first through hole is provided on the base plate. The riveting fixture includes: a positioning base having a positioning hole for placing the gear shaft and a bearing surface for placing the base plate; when the gear shaft is placed in the positioning hole and the base plate is placed on the bearing surface, the riveting section passes through the first through hole, and the embedded groove is located in the first through hole; a movable member arranged opposite to the positioning base and movable between a first position and a second position relative to the positioning base; a ejector pin mounted on the movable member and coaxially arranged with the positioning hole; the end of the ejector pin has an annular protrusion, the inner diameter of which is slightly larger than the outer diameter of the riveting section; when the movable member is in the first position, the ejector pin is separated from the base plate; during the movement of the movable member from the first position to the second position, the annular protrusion contacts and squeezes the base plate to deform it, so that the deformed part of the base plate is embedded in the embedded groove, thereby realizing the riveting between the gear shaft and the base plate.

[0007] Preferably, the movable part and the positioning base are further provided with a pressure plate that is elastically connected to the movable part, and the pressure plate is provided with a second through hole arranged coaxially with the ejector pin, and the ejector pin can move relative to the pressure plate along its axial direction within the second through hole.

[0008] Preferably, when the movable member is in the first position, the annular protrusion is located in the second through hole; during the movement of the movable member from the first position to the second position, the pressure plate contacts and presses the base plate in advance compared to the ejector pin to flatten the base plate.

[0009] Preferably, at least two guide rods arranged in the same direction are fixedly connected to the pressure plate. The guide rods pass through the movable part and can move relative to the movable part along their axial direction. The end of the guide rod is provided with a first limiting block to prevent it from falling off the movable part. At least one guide rod is sleeved with a compression spring with its two ends abutting against the movable part and the pressure plate respectively. The compression spring can push the pressure plate so that the first limiting block abuts against the movable part.

[0010] Preferably, a positioning key is installed on the positioning base, and a positioning keyway adapted to the positioning key is provided on the base plate.

[0011] Preferably, there are five gear shafts, four of which are of equal length and are defined as the first gear shaft, and the other gear shaft is defined as the second gear shaft, and the length of the second gear shaft is less than the length of the first gear shaft; there are also five positioning holes and five first through holes, which are arranged in a one-to-one correspondence.

[0012] Preferably, the positioning base includes at least a first plate and a second plate, the first plate being fixedly connected to the second plate by bolts; four positioning holes penetrating the first plate, four first gear shafts being respectively inserted into the four positioning holes and abutting against the second plate; another positioning hole is located on the first plate and a mounting groove penetrating the bottom surface of the first plate is provided at the bottom of the positioning hole, a limiting member is provided in the mounting groove, and the second gear shaft is inserted into the positioning hole and abuts against the limiting member.

[0013] Preferably, the riveting fixture is installed on the press table, and a cylinder is installed on the positioning base. At least one connecting rod is installed on the actuating end of the cylinder, and the positioning base also has a third through hole corresponding to the connecting rod. The operation of the cylinder drives the connecting rod to move, thereby pushing the base plate away from the positioning base.

[0014] Preferably, the wall thickness of the annular protrusion is 0.8-1.2 mm.

[0015] Preferably, the gear shaft and the first through hole are clearance fit with a clearance of 0.03-0.05 mm.

[0016] The above-mentioned technical solutions adopted in the embodiments of this utility model can achieve the following beneficial effects: The positioning base ensures the consistency of the gear shaft and base plate assembly positions through the cooperation of the positioning holes, bearing surface, and the first through hole on the base plate. Furthermore, existing riveting methods that rely on gear shaft end deformation suffer from insufficient flatness and perpendicularity to meet product requirements, and may even result in insufficient pull-out force of the gear shaft after riveting. This riveting fixture, however, uses base plate deformation, where an annular protrusion presses the base plate to embed the deformed portion into the gear shaft's inner groove, forming a locking structure. Compared to existing riveting methods that rely on gear shaft deformation, this method more effectively controls deformation and improves connection strength. Moreover, the back of the riveted base plate is free of uneven protrusions, resulting in significantly improved flatness compared to existing technologies. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the three-dimensional structure of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the three-dimensional structure of the present invention. Figure 2 ; Figure 3 This is a three-dimensional structural cross-sectional view of the present invention; Figure 4 This is an assembly diagram of the base plate and positioning base of this utility model; Figure 5 This is an exploded view of the base plate and positioning base of this utility model; Figure 6 This is an exploded view of the first plate and the limiting component of this utility model; Figure 7 This is a three-dimensional structural diagram of the present invention when the ejector pin contacts the base plate; Figure 8 This is a three-dimensional structural cross-sectional view of the structure between the base plate and the pressure plate of this utility model; Figure 9 This is a three-dimensional structural sectional view of the base plate, positioning base, and connecting rod of this utility model; Figure label: 11-First gear shaft; 111-Riveted section; 112-Inner groove; 12-Second gear shaft; 2-Base plate; 21-First through hole; 22-Locking keyway; 3-Positioning base; 31-Positioning key; 32-First plate; 321-Positioning hole; 322-Mounting groove; 323-Bearing surface; 33-Second plate; 34-Limiting component; 35-Third through hole; 36-First guide post; 37-Positioning sleeve; 4-Moving component; 41-Third plate; 411-Second guide post; 42-Fourth plate; 5-Ejector pin; 51-Annular protrusion; 52-Second limiting block; 6-Pressure plate; 61-Second through hole; 62-Guide rod; 621-First limit block; 63-Compression spring; 7-Tabletop; 8-Cylinder; 81-Connecting rod. Detailed Implementation

[0018] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0019] The technical solutions provided by the various embodiments of this utility model are described in detail below with reference to the accompanying drawings.

[0020] Reference Figures 1 to 9 As shown, this utility model embodiment provides a gear shaft riveting fixture for riveting a gear shaft onto a base plate 2. The gear shaft has a riveting section 111 at one end and an embedded groove 112 formed on the outer peripheral wall of the riveting section 111. A first through hole 21 is provided on the base plate 2.

[0021] The riveting fixture mainly includes a positioning base 3, a movable part 4, and a ejector pin 5. The positioning base 3 has a positioning hole 321 for placing the gear shaft and a bearing surface 323 for placing the base plate 2. When the gear shaft is placed in the positioning hole 321 and the base plate 2 is placed on the bearing surface 323, the riveting section 111 passes through the first through hole 21, and the inner groove 112 is located in the first through hole 21. The movable part 4 is arranged opposite to the positioning base 3 and can move relative to the positioning base 3 between a first position and a second position. The ejector pin 5 is mounted on the movable part 4 and is coaxially arranged with the positioning hole 321. The end of the ejector pin 5 has an annular protrusion 51, the inner diameter of which is slightly larger than the outer diameter of the riveting section 111 (generally, it is preferable that the inner diameter of the annular protrusion 51 is 0.5 mm larger than the outer diameter of the riveting section 111).

[0022] When the movable part 4 is in the first position, the ejector pin 5 separates from the base plate 2 (e.g., Figure 3 During the movement of the movable part 4 from the first position to the second position (e.g.) Figure 7 The annular protrusion 51 contacts and presses the base plate 2 to deform, so that the deformed part of the base plate 2 is embedded in the inner groove 112, thereby realizing the riveting between the gear shaft and the base plate 2.

[0023] During operation, the gear shaft is inserted into the positioning hole 321 of the positioning base 3, and the base plate 2 is placed on the bearing surface, so that the riveting section 111 of the gear shaft passes through the first through hole 21 of the base plate 2, and the inner groove 112 is located in the first through hole 21. Subsequently, the movable part 4 drives the ejector pin 5 to move from the initial first position (the ejector pin 5 is separated from the base plate 2) to the second position, and the annular protrusion 51 at the end of the ejector pin 5 gradually approaches the base plate 2. Since the inner diameter of the annular protrusion 51 is slightly larger than the outer diameter of the riveting section 111, it can be sleeved on the outer circumference of the riveting section 111 and contact the base plate 2; during the process of the movable part 4 moving to the second position, the annular protrusion 51 squeezes the edge of the corresponding first through hole 21 of the base plate 2, causing it to undergo plastic deformation. The deformed part of the base plate 2 is squeezed and embedded in the inner groove 112 of the gear shaft, forming an axial locking structure, and realizing the riveting of the gear shaft and the base plate 2.

[0024] The positioning base 3, through the cooperation of the positioning hole 321, the bearing surface, and the first through hole 21 on the base plate 2, ensures the consistency of the assembly position between the gear shaft and the base plate 2. Furthermore, existing riveting methods that rely on deformation of the gear shaft end suffer from insufficient flatness and perpendicularity to meet product requirements, and may even result in insufficient pull-out force of the gear shaft after riveting. This riveting fixture, however, uses a deformation method on the base plate 2. Specifically, the annular protrusion 51 presses the base plate 2, causing the deformed portion to embed into the gear shaft's inner groove 112, forming a locking structure. Compared to gear shaft deformation riveting, this method more effectively controls deformation and improves connection strength. Moreover, the back of the base plate 2 after riveting will not have uneven protrusions, significantly improving flatness compared to existing technologies.

[0025] It should be noted that, in order to ensure the perpendicularity of the gear shaft on the base plate 2, the gear shaft and the first through hole 21 are in clearance fit with a clearance of 0.03-0.05mm. If the clearance is too large, the perpendicularity of the gear shaft cannot be guaranteed. If the perpendicularity deviation between the gear shaft and the base plate 2 is too large, it will cause the gear to jam or the gear to be subjected to uneven force during subsequent assembly of the transmission gear. If the clearance is too small, or if it is an interference fit or a transition fit, the gear shaft will not be able to be placed into the positioning hole and will not be able to be riveted.

[0026] In some practical applications, refer to Figures 3 to 5 As shown, a pressure plate 6 is elastically connected to the movable member 4 between the movable member 4 and the positioning base 3. The pressure plate 6 has a second through hole 61 coaxially arranged with the ejector pin 5, allowing the ejector pin 5 to move axially relative to the pressure plate 6 within the second through hole 61. Specifically, when the movable member 4 is in the first position, the annular protrusion 51 is located within the second through hole 61. During the movement of the movable member 4 from the first position to the second position, the pressure plate 6 contacts and presses the base plate 2 before the ejector pin 5 to flatten the base plate 2.

[0027] In this embodiment, when the movable component 4 drives the ejector pin 5 downward, the elastically connected pressure plate 6 first contacts the surface of the base plate 2, generating a gradually increasing pre-pressure through elastic action. This flattens the slight bending of the base plate 2 caused by processing or transportation (generally, the bending range is ≤0.5mm), ensuring that the base plate 2 is completely in contact with the bearing surface of the positioning base 3. After the pressure plate 6 is pre-flattened, the ejector pin 5 passes through the second through hole 61 of the pressure plate 6 and presses against the base plate 2 axially. The second through hole 61 also forms a radial limit for the ejector pin 5, preventing the ejector pin 5 from directly contacting the base plate 2 and causing the ejector pin 5 to deviate. Subsequently, the annular protrusion 51 at the end of the ejector pin 5 presses against the edge of the through hole in the base plate 2, causing it to plastically deform and embed into the gear shaft inner groove 112.

[0028] After the base plate 2 is flattened, it fits tightly with the positioning base 3. There is no suspension during the riveting process, and the gear shaft will not be subjected to additional external stress (mainly the radial force generated between it and the corresponding positioning hole) after riveting. The gear shaft can be easily removed from the positioning hole 321, and the perpendicularity of the gear shaft is also ensured.

[0029] Specifically, refer to Figure 8 As shown, the elastic connection between the movable part 4 and the pressure plate 6 can be achieved in at least the following manner: at least two guide rods 62 arranged in the same direction are fixedly connected to the pressure plate 6. The guide rods 62 pass through the movable part 4 and can move relative to the movable part 4 along its axial direction. The end of the guide rod 62 is provided with a first limiting block 621 to prevent it from falling off the movable part 4. At least one guide rod 62 is sleeved with a compression spring 63 (preferably model YSWS-D17-L60) with its two ends abutting against the movable part 4 and the pressure plate 6 respectively. The compression spring 63 can push the pressure plate 6 so that the first limiting block 621 abuts against the movable part 4.

[0030] The pressure plate 6 is connected to the movable part 4 via four guide rods 62 moving in the same direction. In its natural state, the two ends of the compression spring press against the lower surface of the movable part 4 and the upper surface of the pressure plate 6, respectively, pushing the pressure plate 6 away from the movable part 4, so that the limiting block always remains in contact with the upper surface of the movable part 4. When the movable part 4 moves downward under the driving force (such as the hydraulic rod of the press), the pressure plate 6 contacts the base plate 2, at which point the compression spring is at its natural length. As the movable part 4 continues to move downward, the guide rods 62 slide upward relative to the movable part 4, and the compression spring 63 is compressed (the amount of compression increases with the stroke of the movable part 4), pushing the pressure plate 6 to apply a preload to the base plate 2 (the force of the compression spring 63 is proportional to the amount of compression; for example, when the spring stiffness is 5 N / mm, a compression of 2 mm produces a 10 N preload).

[0031] When the spring is compressed to a preset stroke (e.g., 5mm), the ejector pin 5 passes through the second through hole 61 of the pressure plate 6 and contacts the base plate 2, entering the riveting stage; during the riveting stage, the compression spring 63 ensures that the base plate 2 always fits against the positioning base 3 during the riveting process. After the riveting is completed, the movable part 4 moves upward, the compression spring 63 releases its elastic potential energy, pushes the pressure plate 6 to reset with the guide rod 62, and the limit block re-clamps against the movable part 4.

[0032] In other practical applications, a positioning key 31 is installed on the positioning base 3 (e.g., Figures 4 to 5 The base plate 2 is provided with a positioning keyway 22 that is adapted to the positioning key 31. The positioning key 31 can be used to achieve the initial positioning of the base plate 2. The positioning key 31, together with the gear shaft itself, can achieve the precise positioning of the base plate 2.

[0033] In other practical applications, the gear shafts are configured with five (e.g., Figure 5 The four gear shafts are of equal length and are defined as the first gear shaft 11, while the other gear shaft is defined as the second gear shaft 12, and the length of the second gear shaft 12 is less than the length of the first gear shaft 11. Five positioning holes 321 and five first through holes 21 are also provided, arranged in a one-to-one correspondence. This arrangement allows for the simultaneous riveting of all five gear shafts.

[0034] Furthermore, in actual processing, considering production needs, four gear shafts are of equal length, while the other gear shaft is shorter. Therefore, the positioning holes 321 need to correspond to each gear shaft to ensure that the top surfaces of the five gear shafts are flush after all five gear shafts are placed in their corresponding positioning holes 321. Specifically, the positioning base 3 includes at least a first plate 32 and a second plate 33. The first plate 32 is fixedly connected to the second plate 33 by bolts. Four positioning holes 321 penetrate the first plate 32, and four first gear shafts 11 are respectively inserted into the four positioning holes 321 and abut against the second plate 33. Another positioning hole 321 is located on the first plate 32, and the bottom of the positioning hole 321 is provided with a mounting groove 322 that penetrates the bottom surface of the first plate 32. A limiting member 34 is provided in the mounting groove 322, and the second gear shaft 12 is inserted into the positioning hole 321 and abuts against the limiting member 34.

[0035] In summary, for reference Figures 4 to 5 The positioning base 3 is a split structure, mainly composed of a first plate 32, a second plate 33 and a limiting member 34. The first plate 32 and the second plate 33 are connected by bolts to facilitate the machining of each positioning hole 321. The limiting member 34 is mainly used for raising, that is, when the second gear shaft 12 is inserted into the corresponding positioning hole 321 and abuts against the limiting member 34, it can ensure that the top of the second gear shaft 12 and the other four first gear shafts 11 are flush.

[0036] In other practical applications, the riveting fixture is based on any of the above embodiments: (Refer to...) Figure 9 As shown, the riveting fixture is installed on the table 7 of the press (the press is existing technology and is not specifically shown in the figure). A cylinder 8 is installed on the positioning base 3. At least one connecting rod 81 is installed on the actuating end of the cylinder 8. The positioning base 3 also has a third through hole 35 corresponding to the connecting rod 81. The operation of the cylinder 8 drives the connecting rod 81 to move, so as to push the base plate 2 away from the positioning base 3.

[0037] In this embodiment, the automatic removal of the base plate 2 and the gear shaft is achieved, improving production efficiency. Traditionally, the base plate 2 needs to be manually removed (or with the aid of tools) after riveting. However, the base plate 2 is automatically pushed by the cylinder 8, which speeds up the removal process. Furthermore, after the base plate 2 is pre-raised, it is easier for workers to remove the riveted base plate 2 and gear shaft.

[0038] In some practical applications, the wall thickness of the annular protrusion 51 is 0.8-1.2mm. In actual production, the wall thickness of the annular protrusion 51 is 1mm. If the wall thickness of the annular protrusion 51 is too thin, the indentation on the base plate 2 will be too deep or the inner groove 112 of the gear shaft will not be filled, causing the gear shaft to loosen. (It should be noted that the materials of the base plate, gear shaft, and ejector pin also have a certain impact on the riveting effect. In actual processing, the base plate is made of ST12 material, the gear shaft is made of 100Cr6 material, and the ejector pin is made of SKD61 material.) If the wall thickness of the annular protrusion 51 is too thick, its stress area will be too large, which will cause the indentation on the base plate 2 to be too shallow or the inner groove 112 of the gear shaft to not be filled, also causing the gear shaft to loosen.

[0039] Specifically, four first guide posts 36 are installed on the positioning base 3 (e.g. Figure 1 Each first guide post 36 passes through and slides through the movable part 4, so the movable part 4 can slide vertically relative to the positioning base 3, ensuring the coaxiality between the ejector pin 5 and the corresponding gear shaft, as well as the stability of the gear shaft and the base plate 2 during the riveting process.

[0040] Specifically, refer to Figure 3As shown, the movable component 4 includes a third plate 41 and a fourth plate 42, which are fixedly connected. Each ejector pin 5 has a second limiting block 52 at its top. The ejector pin 5 passes through the third plate 41, and the second limiting block 52 clamps and limits it between the third plate 41 and the fourth plate 42. The split design of the movable component 4 facilitates the installation and removal of the ejector pins 5, and is beneficial for daily maintenance. At least two second guide posts 411 are provided on the third plate 41, and the positioning base 3 is provided with positioning sleeves 37 corresponding to the second guide posts 411. The second guide posts 411 are inserted into the corresponding positioning sleeves 37. By guiding the second guide posts 411 through the positioning sleeves 37, the coaxiality between the gear shaft and the corresponding ejector pin 5 can be further stabilized during the riveting process between the gear shaft and the base plate 2.

[0041] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A gear shaft riveting fixture for riveting a gear shaft onto a base plate (2), characterized in that: The gear shaft has a riveting section (111) at one end and an inner groove (112) formed on the outer peripheral wall of the riveting section (111); a first through hole (21) is provided on the base plate (2). The riveting fixture includes: The positioning base (3) has a positioning hole (321) for placing the gear shaft and a bearing surface (323) for placing the base plate (2); when the gear shaft is placed in the positioning hole (321) and the base plate (2) is placed on the bearing surface (323), the riveting section (111) penetrates the first through hole (21) and the inner groove (112) is located in the first through hole (21); The movable part (4) is arranged opposite to the positioning base (3) and can move between a first position and a second position relative to the positioning base (3); The ejector pin (5) is mounted on the movable part (4) and is coaxially arranged with the positioning hole (321); the end of the ejector pin has an annular protrusion (51), the inner diameter of which is slightly larger than the outer diameter of the riveting section (111); When the movable part (4) is in the first position, the ejector pin (5) separates from the base plate (2); during the process of the movable part (4) moving from the first position to the second position, the annular protrusion (51) contacts and squeezes the base plate (2) to deform, so that the deformed part of the base plate (2) is embedded in the inner groove (112) to realize the riveting between the gear shaft and the base plate (2).

2. The gear shaft riveting fixture according to claim 1, characterized in that: The movable part (4) and the positioning base (3) are further provided with a pressure plate (6) that is elastically connected to the movable part (4), and the pressure plate (6) is provided with a second through hole (61) arranged coaxially with the ejector pin (5), and the ejector pin (5) can move relative to the pressure plate (6) along its axial direction in the second through hole (61).

3. The gear shaft riveting fixture according to claim 2, characterized in that: When the movable part (4) is in the first position, the annular protrusion (51) is located in the second through hole (61); during the process of the movable part (4) moving from the first position to the second position, the pressure plate (6) contacts and presses the base plate (2) in advance compared to the ejector pin (5) to flatten the base plate (2).

4. The gear shaft riveting fixture according to claim 2, characterized in that: At least two guide rods (62) arranged in the same direction are fixedly connected to the pressure plate (6). The guide rods (62) pass through the movable part (4) and can move relative to the movable part (4) along their axial direction. The end of the guide rod (62) is provided with a first limiting block (621) to prevent it from falling off the movable part (4). At least one guide rod (62) is sleeved with a compression spring (63) with its two ends abutting against the movable part (4) and the pressure plate (6) respectively. The compression spring (63) can push the pressure plate (6) so that the first limiting block (621) abuts against the movable part (4).

5. The gear shaft riveting fixture according to claim 1, characterized in that: The positioning base (3) is equipped with a positioning key (31), and the base plate (2) is provided with a positioning keyway (22) that is compatible with the positioning key (31).

6. The gear shaft riveting fixture according to claim 1, characterized in that: Five gear shafts are configured, four of which are of equal length and are defined as the first gear shaft (11), and the other gear shaft is defined as the second gear shaft (12), and the length of the second gear shaft (12) is less than the length of the first gear shaft (11); five positioning holes (321) and five first through holes (21) are also configured, and they are arranged in a one-to-one correspondence.

7. The gear shaft riveting fixture according to claim 6, characterized in that: The positioning base (3) includes at least a first plate (32) and a second plate (33), wherein the first plate (32) is fixedly connected to the second plate (33) by bolts; Four positioning holes (321) penetrate the first plate (32), and four first gear shafts (11) are respectively inserted into the four positioning holes (321) and abut against the second plate (33); Another positioning hole (321) is located on the first plate (32) and the bottom of the positioning hole (321) is provided with a mounting groove (322) that penetrates the bottom surface of the first plate (32). A limiting member (34) is provided in the mounting groove (322). The second gear shaft (12) is inserted into the positioning hole (321) and abuts against the limiting member (34).

8. A gear shaft riveting fixture according to claim 1, characterized in that, The riveting fixture is installed on the table (7) of the press. A cylinder (8) is installed on the positioning base (3). At least one connecting rod (81) is installed on the actuating end of the cylinder (8). The positioning base (3) also has a third through hole (35) corresponding to the connecting rod (81). The cylinder (8) drives the connecting rod (81) to move, so as to push the base plate (2) away from the positioning base (3).

9. A gear shaft riveting fixture according to claim 1, characterized in that, The wall thickness of the annular protrusion (51) is 0.8-1.2 mm.

10. A gear shaft riveting fixture according to claim 1, characterized in that, The gear shaft and the first through hole (21) are clearance fit with a clearance of 0.03-0.05 mm.

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