Method and apparatus for spin riveting a drive shaft

Abstract

The present application relates to the technical field of transmission shaft, in particular to a transmission shaft spin riveting method and device. The transmission shaft spin riveting method comprises the following steps: positioning the transmission shaft assembly on the rotating unit; adsorbing and positioning the protective cover on the lower side of the press-fitting unit; based on the positioning completion of the transmission shaft assembly and the protective cover, controlling the press-fitting unit to descend by a first distance, so that the protective cover is press-fitted and positioned, and the press-fitting unit applies a first downward pressure to the protective cover; based on the press-fitting and positioning of the protective cover, controlling the press-fitting unit to ascend by a second distance, so that the press-fitting unit applies a second downward pressure to the protective cover; based on the press-fitting unit applying the second downward pressure to the protective cover, controlling the rotating unit to drive the transmission shaft assembly to rotate at a first rotating speed; based on the transmission shaft assembly rotating at the first rotating speed, controlling the flanging unit to extrude and flange the protective cover. Thus, the problem of short service life of the thrust bearing in the working condition that the rotating unit drives the transmission shaft assembly to rotate and also needs to bear the downward pressure is solved.

Description

Technical Field

[0001] This invention relates to the field of transmission shaft technology, and more specifically, to a method and apparatus for riveting transmission shafts. Background Technology

[0002] A driveshaft is a rigid shaft component in a mechanical transmission system that connects two components with different axes or varying relative positions, transmitting torque and speed. Its core function is power transmission, and it is widely used in automobiles, construction machinery, and ships. For example, in an automotive transmission system, one end of the driveshaft connects to the power output end, such as the gearbox, and the other end connects to the power input end, such as the differential. The driveshaft transmits the power from the engine, after being reduced and increased in torque by the gearbox, to the differential, which then distributes it to the drive wheels, ultimately transmitting it to the wheels via the drive shaft. A universal joint is a core component in a mechanical transmission system that enables the transmission of power between shafts with different axes at varying angles. During vehicle operation, the gearbox and differential at both ends of the driveshaft will experience angular deviations or slight axial displacements due to suspension bumps and changes in vehicle posture. Ordinary rigid shafts cannot adapt to these dynamic changes; therefore, the driveshaft must be paired with a universal joint to form a driveshaft assembly.

[0003] A ball cage universal joint is a type of universal joint. A ball cage universal joint includes a bell-shaped housing, an inner star wheel, a cage, and steel balls.

[0004] The drive shaft assembly includes a shaft, a ball joint, a sliding spline, a counterweight, and a protective cover. When installing the protective cover onto the bell-shaped housing of the ball joint, it needs to be press-fitted onto the bell-shaped housing and then riveted. During the riveting process, the rotating unit drives the drive shaft assembly to rotate. The rotating unit needs to withstand the downward pressure of the protective cover being pressed onto the bell-shaped housing. After long-term operation, the thrust bearing on the rotating unit is prone to damage. Summary of the Invention

[0005] To address the issue of short thrust bearing life under conditions where the rotating unit drives the transmission shaft assembly to rotate while also bearing downward pressure, this invention provides a transmission shaft riveting method and apparatus.

[0006] In a first aspect, the present invention provides a method for riveting a transmission shaft, comprising:

[0007] The drive shaft assembly is positioned on the upper side of the rotating unit; wherein, the drive shaft assembly includes a shaft and a ball cage universal joint; the bell-shaped cover of the ball cage universal joint is connected to the shaft; when the drive shaft assembly is positioned, the shaft is vertically arranged and the bell-shaped cover is located at the top of the shaft;

[0008] The protective cover is positioned by adsorption on the underside of the pressing unit; wherein the pressing unit is located above the rotating unit;

[0009] Based on the completion of positioning of the drive shaft assembly and the protective cover, the pressing unit is controlled to descend a first distance to press and position the protective cover, and the pressing unit applies a first downward force to the protective cover; wherein, in the pressed and positioned state, the protective cover is sleeved on the outside of the bell-shaped cover of the ball joint, and the protective cover and the bell-shaped cover of the ball joint are interference-fitted.

[0010] Based on the protective cover press-fit positioning, the press-fit unit is controlled to rise a second distance so that the press-fit unit applies a second downward pressure to the protective cover; wherein, the second downward pressure is less than the first downward pressure;

[0011] Based on the pressure-fitting unit applying a second downward pressure to the protective cover, the rotating unit is controlled to drive the transmission shaft assembly to rotate at a first speed.

[0012] Based on the rotation of the drive shaft assembly at the first speed, the edge-rolling unit is controlled to press and roll the outer side of the protective cover.

[0013] In some embodiments, before the drive shaft assembly and the protective cover are both positioned, and the pressing unit is controlled to descend a first distance to press-fit the protective cover into position, the drive shaft riveting method further includes:

[0014] Once the drive shaft assembly and the protective cover are both positioned, the auxiliary support unit is controlled to rise until it abuts the bottom end of the shaft of the drive shaft assembly.

[0015] In some embodiments, before applying a second downward pressure to the protective cover based on the pressing unit and controlling the rotating unit to drive the drive shaft assembly to rotate, the drive shaft riveting method further includes:

[0016] The press-fitting unit applies a second downward pressure to the protective cover, controlling the auxiliary support unit to descend until it detaches from the drive shaft assembly.

[0017] In some embodiments, before controlling the pressing unit to rise a second distance based on the press-fitting positioning of the protective cover, so as to apply a second downward pressure to the protective cover by the pressing unit, the drive shaft riveting method further includes:

[0018] Based on the press-fit positioning of the protective cover, a first volume of grease is injected into the protective cover.

[0019] In some embodiments, the drive shaft riveting method further includes:

[0020] Based on the fact that the drive shaft assembly rotates at the first speed for a first duration, the edge-rolling unit is controlled to disengage from the drive shaft assembly, and the rotating unit is controlled to stop, thus completing the initial edge-rolling.

[0021] Based on the completion of the initial edge rolling, a second volume of grease is injected into the protective cover;

[0022] Based on the amount of grease injected reaching the sum of the first volume and the second volume, the rotating unit is controlled to drive the transmission shaft assembly to rotate at a second speed;

[0023] Based on the rotation of the drive shaft assembly at the second speed, the edge-rolling unit is controlled to press and roll the outer side of the protective cover.

[0024] Based on the fact that the drive shaft assembly rotates at the second speed for a second duration, the edge-rolling unit is controlled to disengage from the drive shaft assembly, and the rotating unit is controlled to remain stationary, thus completing two edge-rolling operations.

[0025] In some embodiments, the ratio of the first volume to the second volume is greater than 1.

[0026] In some embodiments, the first rotational speed is greater than the second rotational speed.

[0027] In some embodiments, before the grease-based injection amount reaches the sum of the first volume and the second volume, and the rotating unit is controlled to drive the drive shaft assembly to rotate at a second rotational speed, the drive shaft riveting method further includes:

[0028] Based on the amount of grease injected reaching the sum of the first volume and the second volume, the pressing unit is controlled to rise to a preset position so that the pressing unit is detached from the protective cover;

[0029] Based on the fact that the pressing unit is located at the preset position, the disengagement time of the pressing unit is accumulated;

[0030] Based on the third duration of the disengagement, the pressing unit is controlled to descend until the pressing unit applies a third downward pressure to the protective cover.

[0031] In some embodiments, the third downward pressure is greater than the second downward pressure; the third downward pressure is less than the first downward pressure.

[0032] Secondly, the present invention provides a drive shaft riveting device, which is applied to the drive shaft riveting method of any embodiment in the first aspect;

[0033] The drive shaft riveting device includes:

[0034] frame;

[0035] A rotating unit is connected to the frame; the rotating unit includes a positioning stage and a rotating drive unit; the rotating drive unit drives the positioning stage to rotate about a vertical axis.

[0036] A pressing unit is connected to the frame; the pressing unit is located above the rotating unit; the pressing unit includes a pressing head and a pressing drive unit; the pressing drive unit drives the pressing head to move up and down;

[0037] The oil injection unit includes an oil injection pipe and an oil storage tank; the oil injection pipe is arranged vertically; the oil injection pipe passes through the middle of the pressure head; the top end of the oil injection pipe is connected to the oil storage tank; the oil storage tank is fixedly connected to the frame.

[0038] A curling unit is connected to the frame; the curling unit includes a rolling roller and a displacement driving unit; the axis of the rolling roller is vertically arranged; the displacement driving unit drives the rolling roller to move.

[0039] To address the problem of short thrust bearing life under conditions where the rotating unit drives the transmission shaft assembly to rotate while also bearing downforce, this invention has the following advantages:

[0040] After the press-fitting unit descends a first distance and uses a first downward pressure to press-fit and position the protective cover on the outside of the bell-shaped cover, the press-fitting unit is then raised a second distance and a second downward pressure, less than the first, is used to continuously position the protective cover before riveting. This reduces the downward pressure on the thrust bearing during riveting, ensuring that the combined downward pressure and riveting pressure will not damage the thrust bearing even after long-term use. Attached Figure Description

[0041] Figure 1 A schematic flowchart of a drive shaft riveting method according to one embodiment is shown;

[0042] Figure 2 It shows that the application is used Figure 1 A schematic diagram of the drive shaft riveting device in the drive shaft riveting method.

[0043] Reference numerals: 10 Drive shaft assembly; 11 Shaft; 12 Ball cage universal joint; 20 Protective cover; 30 Rotary unit; 31 Positioning table; 32 Rotary drive unit; 40 Pressing unit; 41 Press head; 42 Pressing drive unit; 50 Oil injection unit; 51 Oil injection pipe; 52 Oil reservoir; 60 Hemming unit; 61 Rolling roller; 62 Displacement drive unit; 70 Auxiliary support unit; 71 Auxiliary support platform; 72 Lifting drive unit. Detailed Implementation

[0044] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, and are not intended to imply any limitation on the scope of the disclosure.

[0045] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation or being constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances. In addition, the terms "installed", "set up", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0046] A driveshaft is a rigid shaft component in a mechanical transmission system that connects two components with different axes or varying relative positions, transmitting torque and speed. A universal joint is a core component in a mechanical transmission system that enables the transmission of power between rotating shafts with different axes at varying angles. Driveshafts are widely used; for example, in automobiles, driveshafts are often paired with universal joints to form a driveshaft assembly 10. A ball-cage universal joint 12 is a type of universal joint, comprising a bell-shaped housing, inner star wheel, cage, and steel balls. The driveshaft assembly 10 includes a shaft 11, a ball-cage universal joint 12, a sliding spline, a balance weight, and a protective cover 20. When installing the protective cover 20 onto the end face of the ball-cage universal joint 12, it needs to be press-fitted and then riveted, followed by the injection of grease into the protective cover 20. How to avoid the combined pressure of excessive press-fitting and riveting causing damage to the thrust bearing is a problem that urgently needs to be solved. To address the issue of short thrust bearing life under conditions where the rotating unit 30 drives the transmission shaft assembly 10 to rotate while also bearing downward pressure, this invention provides a transmission shaft riveting method and apparatus.

[0047] Example 1:

[0048] This embodiment provides a method for riveting a transmission shaft, such as... Figure 1 and Figure 2 As shown, Figure 1 This is a flowchart of a method for riveting a transmission shaft. Figure 2 This is a schematic diagram of a drive shaft riveting device that applies the above method. (Reference) Figure 1 and Figure 2 The riveting method for the drive shaft includes steps S10 to S50, which are explained in detail below:

[0049] Step S10: Position the drive shaft assembly 10 on the upper side of the rotating unit 30; wherein, the drive shaft assembly 10 includes a shaft 11 and a ball cage universal joint 12; the bell-shaped cover of the ball cage universal joint 12 is connected to the shaft 11; in the state where the drive shaft assembly 10 is positioned, the shaft 11 is vertically arranged, and the bell-shaped cover is located at the top of the shaft 11; in this state, the rotation center of the rotating unit 30 is coaxial with the axis of the shaft 11 and the bell-shaped cover, and the above three components are arranged sequentially from bottom to top.

[0050] Step S20: Position the protective cover 20 by adsorption on the lower side of the pressing unit 40; based on the shape of the upper side of the protective cover 20, the shape of the lower side of the pressing unit 40 can be set accordingly, and a magnet is used to adsorb the protective cover 20, which can achieve a good positioning effect and prevent damage to the protective cover 20 during the positioning process. The pressing unit 40 is located above the rotating unit 30.

[0051] Step S30: Based on the completion of positioning of both the drive shaft assembly 10 and the protective cover 20: control the pressing unit 40 to descend a first distance to press and position the protective cover 20, and the pressing unit 40 applies a first downward pressure to the protective cover 20; wherein, in the pressed and positioned state, the protective cover 20 is sleeved on the outside of the bell-shaped cover of the ball joint 12, and the protective cover 20 and the bell-shaped cover of the ball joint 12 are interference-fitted; the first downward pressure can be set to 10kN, so that the protective cover 20 can be firmly pressed and installed on the outside of the bell-shaped cover.

[0052] Step S40: Based on the press-fit positioning of the protective cover 20, control the press-fit unit 40 to rise a second distance so that the press-fit unit 40 applies a second downward pressure to the protective cover 20; wherein, the second downward pressure is less than the first downward pressure; although the press-fit positioning of the protective cover 20 has been completed in step S30, continuing to apply a smaller second downward pressure to the protective cover 20 after the press-fit unit 40 rises a second distance can press the protective cover 20 against the outside of the bell-shaped cover, further preventing the protective cover 20 from shifting or even falling off due to centrifugal force or the force of the edge-rolling unit 60 during the subsequent riveting process.

[0053] Step S50: Apply a second downward pressure to the protective cover 20 based on the press-fitting unit 40, and control the rotating unit 30 to drive the transmission shaft assembly 10 to rotate at the first speed; a servo motor can be used to drive the rotating unit 30 to drive the transmission shaft assembly 10 to rotate, which makes it easier to control the speed and torque of the rotating unit 30.

[0054] Step S60: Based on the rotation of the drive shaft assembly 10 at a first rotational speed, the crimping unit 60 is controlled to press and crimp the outer side of the protective cover 20. This allows the protective cover 20, after being press-fitted and positioned, to be completely installed on the outside of the bell-shaped cover after rotational riveting. After the press-fitting unit 40 descends a first distance and uses a first downward pressure to press-fit and position the protective cover 20 on the outside of the bell-shaped cover, the press-fitting unit 40 is controlled to rise a second distance and uses a second downward pressure less than the first downward pressure to continuously position the protective cover 20, and then the protective cover 20 is riveted. This reduces the downward pressure on the protective cover 20 during the riveting process, thereby reducing the downward pressure on the drive shaft assembly 10, and ultimately reducing the downward pressure on the thrust bearing. As a result, the thrust bearing will not be damaged during the riveting process even after the combined downward pressure and the riveting pressure.

[0055] In this embodiment, the second distance can be 0.1mm to 0.3mm, preferably 0.2mm. The first downward pressure can be 8kN to 12kN, preferably 10kN.

[0056] Preferably, the bell-shaped cover of the ball cage universal joint 12 and the shaft 11 can be connected as a single piece. This eliminates the interface added to the ball cage universal joint 12 by the separate connection, makes the overall mechanical properties of the ball cage universal joint 12 more uniform, and ensures the coaxiality of the bell-shaped cover and the shaft 11.

[0057] Furthermore, before the transmission shaft assembly 10 and the protective cover 20 are both positioned, and the press-fitting unit 40 is lowered by a first distance to press-fit and position the protective cover 20, and before the press-fitting unit 40 applies a first downward pressure to the protective cover 20, the transmission shaft riveting method further includes step S70, which includes step S71, as detailed below:

[0058] Step S71: With both the drive shaft assembly 10 and the protective cover 20 positioned, control the auxiliary support unit 70 to rise until it abuts the bottom end of the shaft 11 of the drive shaft assembly 10. In this way, during the process of pressing the protective cover 20 with the first downward pressure, the auxiliary support unit 70 can help the rotating unit 30 bear the larger first downward pressure, reducing the possibility of damage to the rotating unit 30 due to pressure.

[0059] Furthermore, before the second downward pressure is applied to the protective cover 20 by the pressing unit 40 and the rotating unit 30 is controlled to drive the drive shaft assembly 10 to rotate, the drive shaft riveting method further includes step S72, which is explained in detail below:

[0060] Step S72: Based on the pressure-fitting unit 40, a second downward pressure is applied to the protective cover 20, and the auxiliary support unit 70 is controlled to descend until it is disengaged from the drive shaft assembly 10. In this way, after the pressure on the protective cover 20 decreases, resulting in a decrease in the pressure on the rotating unit 30, the support of the auxiliary support unit 70 on the rotating unit 30 is removed, thereby allowing the rotating unit 30 to start rotating.

[0061] Furthermore, before controlling the pressing unit 40 to rise a second distance based on the pressing and positioning of the protective cover 20, so that the pressing unit 40 applies a second downward pressure to the protective cover 20, the drive shaft riveting method further includes step S73, which is explained in detail below:

[0062] Step S73: Based on the press-fit positioning of the protective cover 20, at this time the inside of the protective cover 20 and the outside of the bell-shaped shell form a sealed space. Then, inject the first volume of grease into the protective cover 20. This can prevent grease leakage after the press-fit unit 40 rises a second distance, and also play a good role in lubrication and shock absorption of the internal structure of the bell-shaped shell.

[0063] Furthermore, the drive shaft riveting method also includes step S80, which includes steps S81 to S85, as detailed below:

[0064] Step S81: Based on the transmission shaft assembly 10 rotating at a first speed for a first duration, control the hemming unit 60 to disengage from the transmission shaft assembly 10, and control the rotating unit 30 to stop, thus completing the initial hemming.

[0065] Step S82: Based on the completion of the initial edge rolling, inject a second volume of grease into the protective cover 20;

[0066] Step S83: Based on the fact that the amount of grease injected reaches the sum of the first volume and the second volume, control the rotating unit 30 to drive the transmission shaft assembly 10 to rotate at the second speed;

[0067] Step S84: Based on the transmission shaft assembly 10 rotating at a second speed, control the edge curling unit 60 to press and curl the outer side of the protective cover 20;

[0068] Step S85: Based on the second rotation speed of the drive shaft assembly 10 reaching the second duration, control the hemming unit 60 to disengage from the drive shaft assembly 10, and control the rotating unit 30 to remain stationary, thus completing the two hemming operations.

[0069] Because heat is generated during the crimping process, and the grease occupies a certain volume within the sealed cavity of the bell-shaped shell, it will expand when heated, making it more prone to leakage. Therefore, a two-stage grease injection method is used. Injecting all the grease at once may result in insufficient grease spreading during the first riveting process. Two grease injections and riveting steps ensure more even grease spreading. Furthermore, two riveting steps improve the quality of the crimping.

[0070] Furthermore, the ratio of the first volume to the second volume is greater than 1, meaning that the amount of oil injected in the first injection accounts for more than 50% of the total oil volume, thus meeting the sealing requirements within the protective cover 20. However, injecting too much grease may cause grease to overflow during riveting and extrusion. Therefore, injecting more than half the required amount of grease before the first riveting operation has a better effect.

[0071] Furthermore, since the volume of grease injected in the first instance is greater than that injected in the second instance, by setting the first rotation speed to be greater than the second rotation speed, the grease is spread out more evenly after the first riveting.

[0072] Furthermore, before the control unit 30 drives the drive shaft assembly 10 to rotate at the second speed after the amount of grease injected reaches the sum of the first and second volumes, the drive shaft riveting method further includes step S90, which includes steps S91 to S93, as detailed below:

[0073] Step S91: Based on the grease injection volume reaching the sum of the first and second volumes, control the pressing unit 40 to rise to a preset position so that the pressing unit 40 detaches from the protective cover 20. During the initial edge-rolling process, the protective cover 20 generates heat through friction with the outer periphery of the bell-shaped shell, causing the internal temperature of the protective cover 20 to rise. Furthermore, because the protective cover 20 is pressed tightly by the pressing unit 40, the internal air pressure increases, and the second grease injection exacerbates this phenomenon. By setting the pressing unit 40 to detach from the protective cover 20, the internal space of the protective cover 20 can be connected to the atmosphere, thereby releasing the internal air pressure and preventing oil leakage that may result from excessive expansion.

[0074] Step S92: Based on the fact that the pressing unit 40 is located in a preset position, accumulate the disengagement time of the pressing unit 40;

[0075] Step S93: Based on the third duration of the disengagement time, control the pressing unit 40 to descend until the pressing unit 40 applies a third downward pressure to the protective cover 20.

[0076] Furthermore, the third downward pressure is greater than the second downward pressure; the third downward pressure is less than the first downward pressure.

[0077] Since riveting relies on the heat generated by friction to deform the protective cover 20 and rivet it to the outside of the bell-shaped shell, the quality of riveting is related to the rotational speed of the rotating unit 30 and the downward pressure of the pressing unit 40. A faster rotational speed and a greater downward pressure result in higher riveting quality. Because the second rotational speed is less than the first rotational speed, setting the third downward pressure to be greater than the second downward pressure can ensure good riveting quality in both riveting operations.

[0078] Furthermore, such as Figure 2 As shown, the drive shaft riveting device includes: a frame, a rotating unit 30, a pressing unit 40, an oil injection unit 50, and an edge curling unit 60.

[0079] The rotating unit 30 is connected to the frame; the rotating unit 30 includes a positioning table 31 and a rotating drive unit 32; the rotating drive unit 32 drives the positioning table 31 to rotate around the vertical axis; this allows the transmission shaft assembly 10 to be positioned on the positioning table 31 and rotate around the vertical axis at a first speed and a second speed under the drive of the positioning table 31.

[0080] The pressing unit 40 is connected to the frame; the pressing unit 40 is located above the rotating unit 30; the pressing unit 40 includes a pressing head 41 and a pressing drive unit 42; the pressing drive unit 42 drives the pressing head 41 to rise and fall; thus, the pressing head 41 can be used to press the protective cover 20. The drive unit provides a first downward pressure, a second downward pressure, and a third downward pressure to the pressing head 41, and also achieves displacement of the pressing unit 40 by a first distance and a second distance.

[0081] The oil injection unit 50 includes an oil injection pipe 51 and an oil storage tank 52. The oil injection pipe 51 is arranged vertically and passes through the middle of the pressure head 41. The top end of the oil injection pipe 51 is connected to the oil storage tank 52. The oil storage tank 52 is fixedly connected to the frame. In this way, the first volume and the second volume of grease can be injected into the protective cover 20 through the oil injection pipe 51.

[0082] The hemming unit 60 is connected to the frame; the hemming unit 60 includes a rolling roller 61 and a displacement drive unit 62; the axis of the rolling roller 61 is vertically oriented; the displacement drive unit 62 drives the rolling roller 61 to move. When the hemming unit 60 receives a command to start hemming, the displacement drive unit 62 drives the rolling roller 61 to move in a direction perpendicular to the axis of the drive shaft assembly 10, thereby abutting against the protective cover 20 and starting hemming. After hemming is completed, it moves backward in the opposite direction to the above direction and disengages from the protective cover 20.

[0083] In other embodiments, such as Figure 2 As shown, the drive shaft riveting device also includes an auxiliary support unit 70, which includes an auxiliary support platform 71 and a lifting drive unit 72. This allows the lifting drive unit 72 to drive the auxiliary support platform 71 to achieve vertical displacement, providing auxiliary support for the rotating unit 30 when subjected to a second downward pressure.

[0084] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes can be made in form and detail without departing from the scope of this disclosure.

Claims

1. A method for riveting a transmission shaft, characterized in that, The drive shaft riveting method includes: The drive shaft assembly is positioned on the upper side of the rotating unit; wherein, the drive shaft assembly includes a shaft and a ball cage universal joint; the bell-shaped cover of the ball cage universal joint is connected to the shaft; when the drive shaft assembly is positioned, the shaft is vertically arranged and the bell-shaped cover is located at the top of the shaft; The protective cover is positioned by adsorption on the underside of the pressing unit; wherein the pressing unit is located above the rotating unit; Based on the completion of positioning of the drive shaft assembly and the protective cover, the pressing unit is controlled to descend a first distance to press and position the protective cover, and the pressing unit applies a first downward force to the protective cover; wherein, in the pressed and positioned state, the protective cover is sleeved on the outside of the bell-shaped cover of the ball joint, and the protective cover and the bell-shaped cover of the ball joint are interference-fitted. Based on the press-fit positioning of the protective cover, a first volume of grease is injected into the protective cover; Based on injecting a first volume of grease into the protective cover, the pressing unit is controlled to rise a second distance so that the pressing unit applies a second downward pressure to the protective cover; wherein the second downward pressure is less than the first downward pressure; Based on the pressure-fitting unit applying a second downward pressure to the protective cover, the rotating unit is controlled to drive the transmission shaft assembly to rotate at a first speed. Based on the rotation of the drive shaft assembly at the first speed, the edge-rolling unit is controlled to press and roll the outer side of the protective cover. Based on the fact that the drive shaft assembly rotates at the first speed for a first duration, the edge-rolling unit is controlled to disengage from the drive shaft assembly, and the rotating unit is controlled to stop, thus completing the initial edge-rolling. Based on the completion of the initial edge rolling, a second volume of grease is injected into the protective cover; Based on the amount of grease injected reaching the sum of the first volume and the second volume, the rotating unit is controlled to drive the transmission shaft assembly to rotate at a second speed; Based on the rotation of the drive shaft assembly at the second speed, the edge-rolling unit is controlled to press and roll the outer side of the protective cover. Based on the fact that the drive shaft assembly rotates at the second speed for a second duration, the edge-rolling unit is controlled to disengage from the drive shaft assembly, and the rotating unit is controlled to remain stationary, thus completing two edge-rolling operations.

2. The method for riveting a transmission shaft according to claim 1, characterized in that, Before the transmission shaft riveting method further includes, after the positioning of both the transmission shaft assembly and the protective cover is completed, controlling the pressing unit to descend a first distance to press and position the protective cover, and before the pressing unit applies a first downward pressure to the protective cover: Once the drive shaft assembly and the protective cover are both positioned, the auxiliary support unit is controlled to rise until it abuts the bottom end of the shaft of the drive shaft assembly.

3. The method for riveting a transmission shaft according to claim 2, characterized in that, Before the second downward pressure is applied to the protective cover based on the pressing unit and the rotating unit is controlled to drive the drive shaft assembly to rotate, the drive shaft riveting method further includes: The press-fitting unit applies a second downward pressure to the protective cover, controlling the auxiliary support unit to descend until it detaches from the drive shaft assembly.

4. The method for riveting a transmission shaft according to claim 3, characterized in that, The ratio of the first volume to the second volume is greater than 1.

5. A method for riveting a transmission shaft according to claim 4, characterized in that, The first rotational speed is greater than the second rotational speed.

6. The method for riveting a transmission shaft according to claim 5, characterized in that, Before the amount of grease-based injection reaches the sum of the first volume and the second volume, and before the rotating unit is controlled to drive the drive shaft assembly to rotate at the second speed, the drive shaft riveting method further includes: Based on the amount of grease injected reaching the sum of the first volume and the second volume, the pressing unit is controlled to rise to a preset position so that the pressing unit is detached from the protective cover; Based on the fact that the pressing unit is located at the preset position, the disengagement time of the pressing unit is accumulated; Based on the third duration of the disengagement, the pressing unit is controlled to descend until the pressing unit applies a third downward pressure to the protective cover.

7. A method for riveting a transmission shaft according to claim 6, characterized in that, The third downward pressure is greater than the second downward pressure; the third downward pressure is less than the first downward pressure.

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