Pin-connected drive shaft and method of installation

Abstract

The present application relates to the technical field of transmission, in particular to a pin connection transmission shaft and a mounting method. The pin connection transmission shaft comprises a ball cage assembly, a second connecting unit and a lock pin. The ball cage assembly comprises a shell unit and a first connecting unit. The first connecting unit comprises a connecting ring and a first hole. The connecting ring is connected with one end of the shell unit. The inner hole of the connecting ring and the sidewall of the shell unit form a mounting blind hole. The first hole penetrates the sidewall of the connecting ring and communicates with the mounting blind hole. The second connecting unit comprises a first shaft and a second hole. The first shaft is connected with the connecting ring in the mounting blind hole. The second hole penetrates the first shaft. The lock pin passes through the first hole and the second hole in sequence. D1 < D2. D1 is the minimum distance from the first hole to the end of the connecting ring close to the shell unit. D2 is the minimum distance from the first hole to the end of the connecting ring away from the shell unit. Thus, the problem of difficult assembly caused by large resistance during pin connection assembly is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transmission, in particular to a pin connection transmission shaft and a mounting method. BACKGROUND

[0002] As a key structure for torque transmission and component positioning in mechanical transmission system, pin connection transmission shaft is widely used in automobile drive system (such as car half shaft, commercial vehicle transmission shaft), industrial mechanical equipment (such as numerical control machine tool spindle, fan transmission shaft) and aerospace auxiliary transmission device fields. Its core function is to stably transmit power from one end to the other end through the cooperation of lock pin, shaft component and connecting ring, while adapting to the possible radial deviation and angular deviation in the transmission process, and taking into account the connection reliability and assembly convenience.

[0003] In the assembly of the existing pin connection transmission shaft, the blind hole or close fitting design of the elastic sleeve pin coupling structure easily forms a closed space. When the shaft component is pressed in, air is compressed to produce air lock effect, resulting in increased assembly resistance. Not only the assembly time is prolonged, but also the component may be damaged due to forced assembly. If the scheme of opening a through hole in the transmission shaft shell or connecting end to assist air exhaust is adopted, stress concentration area is easily formed around the exhaust hole, which becomes a weak point of fatigue failure under alternating load; and the sealing performance is affected, the external pollutants invade the exhaust hole, and the internal component wear is aggravated. SUMMARY

[0004] In order to solve the problem of difficult assembly caused by large resistance in pin connection assembly, the present application provides a pin connection transmission shaft and a mounting method.

[0005] In the first aspect, the present application provides a pin connection transmission shaft, which comprises:

[0006] A ball cage assembly comprises a shell unit and a first connecting unit. The first connecting unit comprises a connecting ring and a first hole. The connecting ring is connected to one end of the shell unit. The inner hole of the connecting ring and the side wall of the shell unit form a mounting blind hole. The first hole communicates with the mounting blind hole through the side wall of the connecting ring.

[0007] A second connecting unit comprises a first shaft and a second hole. The first shaft is connected to the connecting ring in the mounting blind hole. The second hole penetrates the first shaft.

[0008] A lock pin passes through the first hole and the second hole in sequence.

[0009] Wherein, D1 < D2; D1 is the minimum distance from the first hole to the end of the connecting ring close to the shell unit; D2 is the minimum distance from the first hole to the end of the connecting ring away from the shell unit.

[0010] In some embodiments, the second connecting unit comprises a third hole; the third hole is arranged on the first shaft; one end of the third hole is recessed from the first shaft near the end of the bottom wall of the mounting blind hole, and the other end extends towards the direction close to the second hole and communicates with the second hole.

[0011] In some embodiments, the first shaft and the connecting ring are connected by splines in the mounting blind hole.

[0012] In some embodiments, the inner splines comprise a first inner spline, a second inner spline, and a third inner spline; the first inner spline, the second inner spline, and the third inner spline are sequentially arranged on the inner circumferential wall of the connecting ring in the direction of the shell unit;

[0013] The outer splines comprise a first outer spline, a second outer spline, and a third outer spline; the first outer spline, the second outer spline, and the third outer spline are sequentially arranged on the outer circumferential wall of the first shaft;

[0014] The first inner spline is matched with the first outer spline; the second inner spline is matched with the second outer spline; and the third inner spline is matched with the third outer spline;

[0015] The first hole is located between the first inner spline and the third inner spline; and the second hole is located between the first outer spline and the third outer spline.

[0016] In the mounting state, the maximum gap between the first inner spline and the first outer spline is smaller than the maximum gap between the third inner spline and the third outer spline; or, the interference amount between the first inner spline and the first outer spline is greater than the interference amount between the third inner spline and the third outer spline.

[0017] In some embodiments, in the mounting state, the maximum gap between the first inner spline and the first outer spline is smaller than the maximum gap between the second inner spline and the second outer spline; or, the interference amount between the first inner spline and the first outer spline is greater than the interference amount between the second inner spline and the second outer spline.

[0018] The maximum gap between the second inner spline and the second outer spline is smaller than the maximum gap between the third inner spline and the third outer spline; or, the interference amount between the second inner spline and the second outer spline is greater than the interference amount between the third inner spline and the third outer spline.

[0019] In some embodiments, the shell unit comprises a shell ring, a shell bottom, an avoiding hole, and a sealing cover.

[0020] The bottom of the shell is connected with one end of the shell ring and one end of the connecting ring respectively; the inner hole of the connecting ring and the bottom of the shell form the mounting blind hole; the avoiding hole penetrates the bottom of the shell along the circumference of the connecting ring; one end of the avoiding hole communicates with the hollow chamber surrounded by the shell ring and the bottom of the shell, and the other end communicates with the mounting blind hole; the sealing cover is detachably connected with the bottom of the shell, and the sealing cover seals the avoiding hole.

[0021] In some embodiments, the number of the third holes is multiple; the multiple third holes are arranged along the axial direction of the second hole.

[0022] In some embodiments, 0.4≤D1 / D2≤0.6.

[0023] In the second aspect, the application provides a mounting method of a pin-connected transmission shaft, which is applied to the pin-connected transmission shaft in any of the first aspect; the mounting method of the pin-connected transmission shaft comprises:

[0024] The first shaft part is inserted into the mounting blind hole of the connecting ring, and one end of the first shaft is located on the side of the first hole away from the bottom wall of the mounting blind hole, and the air in the mounting blind hole is discharged from the first hole;

[0025] The first shaft is continuously inserted into the mounting blind hole, and the projection of the end surface of the first shaft along the axial direction of the first shaft coincides with the first hole, and the air in the mounting blind hole is discharged from the first hole;

[0026] The first shaft is continuously inserted into the mounting blind hole until the end of the first shaft abuts against the bottom wall of the mounting blind hole.

[0027] In some embodiments, the second connecting unit comprises a third hole;

[0028] The continuously inserting the first shaft into the mounting blind hole until the end of the first shaft abuts against the bottom wall of the mounting blind hole comprises:

[0029] The first shaft is continuously inserted into the mounting blind hole, and the end surface of the first shaft is located between the first hole and the bottom wall of the mounting blind hole, the air in the mounting blind hole flows to the second hole from the third hole, and is then discharged from the first hole;

[0030] The end of the first shaft abuts against the bottom wall of the mounting blind hole.

[0031] To solve the problem that the assembly of the pin connection is difficult due to large resistance, the application has the following advantages:

[0032] The size of D1 is smaller than D2, which forms a larger axial space at the end of the shell unit away from the connecting ring. When the first shaft is inserted into the mounting blind hole, the air in the closed space can flow to the side space, reducing the air lock resistance caused by the rapid compression of air, and reducing the external force required for assembly. Compared with the design of the prior art relying on exhaust holes, this structure naturally guides the exhaust through space optimization, without the need for additional through holes, avoiding air pressure resistance during assembly, and preserving the structural integrity of the connecting ring.

[0033] The first hole through which the locking pin passes is closer to the shell unit due to the smaller D1, so that the force point of the locking pin is closer to the support position of the shell unit, shortening the length of the force arm from the force point of the locking pin to the support end of the shell unit. This design can reduce the bending stress and deformation of the connecting ring during torque transmission, reduce the risk of fatigue failure of the connecting ring as a cantilever structure, and improve the torsional strength and service life of the overall structure, especially under heavy load or alternating load conditions. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 A schematic diagram of a pin-connected drive shaft is shown in FIG. 1.

[0035] Figure 2 A schematic diagram of a pin-connected drive shaft is shown in FIG. 1. Figure 1 A schematic diagram of a pin-connected drive shaft is shown in FIG. 1.

[0036] Figure 3 A schematic diagram of a pin-connected drive shaft is shown in FIG. 1. Figure 2 A schematic diagram of a pin-connected drive shaft is shown in FIG. 1.

[0037] Figure 4 A schematic diagram of a pin-connected drive shaft is shown in FIG. 1. Figure 1 A schematic diagram of a pin-connected drive shaft is shown in FIG. 1.

[0038] Figure 5 A schematic diagram of a pin-connected drive shaft is shown in FIG. 1. Figure 4 A schematic diagram of a pin-connected drive shaft is shown in FIG. 1.

[0039] Figure 6 A flowchart of a pin-connected drive shaft installation method is shown in FIG. 1.

[0040] Figure 7 A flowchart of a pin-connected drive shaft installation method is shown in FIG. 1.

[0041] REFERENCE NUMERALS:

[0042] 10, ball cage assembly; 11, housing unit; 111, housing ring; 112, housing bottom; 113, escape hole; 114, sealing cover; 12, first connecting unit; 121, connecting ring; 122, first inner spline; 123, second inner spline; 124, third inner spline; 125, first hole; 20, shaft assembly; 21, second connecting unit; 211, first shaft; 212, first outer spline; 213, second outer spline; 214, third outer spline; 215, second hole; 216, third hole; 22, second shaft; 30, locking pin. DETAILED DESCRIPTION

[0043] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be appreciated that these embodiments are discussed only with the intent to provide a more complete understanding of the disclosure, and are not intended to limit the scope of the disclosure in any way.

[0044] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. The terms "a" and "an" are defined as one or more unless explicitly stated otherwise. The terms "another" and "one or more" are defined as at least a second or more unless explicitly stated otherwise. The terms "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "vertical," "horizontal," "lateral," "longitudinal," and the like, as well as derivatives thereof, refer to the orientation or position of an item as shown in the drawings. These terms are used primarily just to better describe the application and its embodiments, and are not intended to limit the orientation or position of the indicated device, element, or component, to a particular orientation or position, or to require that the device, element, or component be constructed and operated in a particular orientation or position. Also, the terms "front," "back," "top," "bottom," "over," "under," and the like, where used in relation to a part or component, are intended to describe the relative position of the part or component with respect to the other parts or components, and are not intended to denote a specific orientation or position of the part or component. The terms "mount," "set," "provided with," "connected," "linked," and the like, should be interpreted broadly. For example, they can be fixed connections, detachable connections, or integral structures; they can be mechanical connections, or electrical connections; they can be direct connections, or indirect connections through intermediaries; or they can be internal connections between two devices, elements, or components. The terms "first," "second," and the like, are used primarily to distinguish different devices, elements, or components (which can or can not be of the same type and construction), and are not intended to denote relative importance or quantity. Unless otherwise stated, "a plurality" means two or more.

[0045] Example 1:

[0046] This embodiment proposes a pin-connected drive shaft, such as... Figure 1 As shown, the assembly includes a ball cage assembly 10, comprising a shell unit 11 and a first connecting unit 12. The first connecting unit 12 includes a connecting ring 121 and a first hole 125. The connecting ring 121 is connected to one end of the shell unit 11. The inner hole of the connecting ring 121 forms a blind mounting hole with a side wall of the shell unit 11; the first hole 125 penetrates the side wall of the connecting ring 121 and communicates with the blind mounting hole.

[0047] The second connecting unit 21 includes a first shaft 211 and a second hole 215. The first shaft 211 is connected to the connecting ring 121 within a blind mounting hole. The outer periphery of the first shaft 211 and the inner hole of the connecting ring 121 form a clearance fit or an interference fit, thereby restricting the radial displacement of the first shaft 211. The second hole 215 penetrates the first shaft 211.

[0048] Locking pin 30 passes through the first hole 125 and the second hole 215 in sequence; locking pin 30 and the first hole 125 are interference fit, which can restrict the axial movement and circumferential rotation of the first shaft 211.

[0049] Where D1 < D2. D1 is the minimum distance from the first hole 125 to the end of the connecting ring 121 closest to the shell unit 11; D2 is the minimum distance from the first hole 125 to the end of the connecting ring 121 furthest from the shell unit 11. This creates a larger axial space at the end of the connecting ring 121 furthest from the shell unit 11. When the first shaft 211 is inserted into the blind hole, the air in the enclosed space can flow towards the reserved space on that side, reducing the airlock resistance caused by the rapid compression of air, which can reduce the external force required for assembly and improve assembly efficiency. Compared with the existing technology that relies on exhaust holes, this structure naturally guides exhaust through space optimization, without the need for additional through holes, thus avoiding air pressure obstruction during assembly and preserving the structural integrity of the connecting ring 121.

[0050] Furthermore, because the first hole 125 through which the locking pin 30 passes is smaller, it is closer to the shell unit 11, making the stress point of the locking pin 30 closer to the support position of the shell unit 11 and shortening the lever arm length of the connecting ring 121. This design can reduce the bending stress and deformation of the connecting ring 121 during torque transmission, reduce its fatigue failure risk as a cantilever structure, and especially under heavy load or alternating load conditions, it can improve the torsional strength and service life of the overall structure.

[0051] Further, the second connecting unit 21 comprises a third hole 216. The third hole 216 is arranged on the first shaft 211; one end of the third hole 216 is recessed from the first shaft 211 near the bottom wall of the mounting blind hole, and the other end extends towards the direction close to the second hole 215 and communicates with the second hole 215.

[0052] When the first shaft 211 is inserted into the mounting blind hole, the air at the bottom of the blind hole can flow to the second hole 215 through the third hole 216, and then be discharged through the communication gap between the second hole 215 and the first hole 125. In this way, air can be more actively and completely guided to discharge, further eliminating air lock resistance, thereby improving assembly efficiency.

[0053] Further, as shown in Figure 3 , the first shaft 211 and the connecting ring 121 are connected by spline connection in the mounting blind hole. The spline connection realizes force transmission through tooth surface engagement, and the contact area is much larger than that of the locking pin 30, so that the stress can be dispersed to multiple teeth of the spline, the concentrated stress is dispersed, the unit area load at the locking pin 30 is reduced, and deformation of the pin connection transmission shaft under large torque or high speed rotation is avoided.

[0054] Further, as shown in Figure 2 , the inner spline comprises a first inner spline 122, a second inner spline 123 and a third inner spline 124. The first inner spline 122, the second inner spline 123 and the third inner spline 124 are sequentially connected and arranged on the inner circumferential wall of the connecting ring 121 in the direction of the shell unit 11.

[0055] As shown in Figure 5 , the outer spline comprises a first outer spline 212, a second outer spline 213 and a third outer spline 214. The first outer spline 212, the second outer spline 213 and the third outer spline 214 are sequentially connected and arranged on the outer circumferential wall of the first shaft 211.

[0056] The first inner spline 122 is matched with the first outer spline 212; the second inner spline 123 is matched with the second outer spline 213; and the third inner spline 124 is matched with the third outer spline 214.

[0057] The first hole 125 is located between the first inner spline 122 and the third inner spline 124; and the second hole 215 is located between the first outer spline 212 and the third outer spline 214.

[0058] The mounting state further comprises that the maximum gap between the first inner spline 122 and the first outer spline 212 is smaller than the maximum gap between the third inner spline 124 and the third outer spline 214; or, the interference amount between the first inner spline 122 and the first outer spline 212 is greater than the interference amount between the third inner spline 124 and the third outer spline 214.

[0059] The third inner spline 124 and the third outer spline 214 correspond to the third hole 216 region of the first shaft 211, and the presence of the third hole 216 weakens the local strength of the first shaft 211. By setting a larger gap or a smaller interference amount, the engagement force of the third inner spline 124 and the third outer spline 214 can be reduced, and the weak structure of the region can be avoided. Overload stress, thereby reducing the risk of fracture near the third hole 216.

[0060] Moreover, the gap between the third inner spline 124 and the third outer spline 214 can form an additional exhaust passage. When assembled, the air at the bottom of the mounting blind hole first enters the third hole 216 through the gap between the third inner spline 124 and the third outer spline 214, and then flows to the second hole 215 through the third hole, and finally is discharged from the first hole 125. This can further improve the exhaust speed and improve the assembly efficiency of the pin-connected transmission shaft.

[0061] The region of the first shaft 211 provided with the first outer spline 212 and the region of the connecting ring 121 provided with the first inner spline 122 have complete structure and higher strength. The larger gap or smaller interference amount of the third inner spline 124 and the third outer spline 214 can reduce the engagement force of the region;

[0062] The cooperation between the first inner spline 122 and the first outer spline 212 is more closely, which can bear the main torque and make up for the insufficient positioning ability of the third inner spline 124 and the third outer spline 214 due to the weak structure.

[0063] Further, the mounting state further includes that the maximum gap between the first inner spline 122 and the first outer spline 212 is smaller than the maximum gap between the second inner spline 123 and the second outer spline 213; or, the interference amount between the first inner spline 122 and the first outer spline 212 is greater than the interference amount between the second inner spline 123 and the second outer spline 213;

[0064] The maximum gap between the second inner spline 123 and the second outer spline 213 is smaller than the maximum gap between the third inner spline 124 and the third outer spline 214; or, the interference amount between the second inner spline 123 and the second outer spline 213 is greater than the interference amount between the third inner spline 124 and the third outer spline 214.

[0065] In this way, the maximum gap between the third inner spline 124 and the third outer spline 214 provides a main exhaust path for air, and the air at the bottom of the mounting blind hole can flow quickly to the gap between the second inner spline 123 and the second outer spline 213; The moderate gap between the second inner spline 123 and the second outer spline 213 serves as a transition exhaust layer, which can discharge air from the first hole 125.

[0066] And the first inner spline 122 and the first outer spline 212 can withstand greater torque by means of the minimum gap or maximum interference, ensuring the high coaxiality of the first shaft 211 and the connecting ring 121, and avoiding eccentric vibration at high speed. The gap or interference between the second inner spline 123 and the second outer spline 213 is moderate, which can serve as a transition buffer section to reduce stress concentration between the first inner spline 122 and the first outer spline 212, and avoid overloading of the first inner spline 122 and the first outer spline 212. The gap between the third inner spline 124 and the third outer spline 214 is the largest, which only serves as an auxiliary guide, and can avoid damage to the weak area of the third hole 216 due to the close meshing of the spline.

[0067] Further, as shown in Figure 2 The shell unit 11 includes a shell ring 111, a shell bottom 112, an avoidance hole 113, and a sealing cover 114. The shell bottom 112 is connected to one end of the shell ring 111 and one end of the connecting ring 121, respectively. The inner hole of the connecting ring 121 and the shell bottom 112 form a mounting blind hole. The avoidance hole 113 penetrates the shell bottom 112 along the circumference of the connecting ring 121. One end of the avoidance hole 113 communicates with the hollow chamber surrounded by the shell ring 111 and the shell bottom 112, and the other end communicates with the mounting blind hole. The inner hole of the connecting ring 121 and the first hole 125 are located in the mounting blind hole. Due to the closed nature of the blind hole, the tool is difficult to penetrate or position, which easily leads to low precision of the inner spline tooth shape and poor coaxiality of the first hole 125 and the inner spline.

[0068] The tool can extend into the hollow chamber of the shell bottom 112 through the avoidance hole 113 to directly cut the inner circumferential wall of the connecting ring 121, thereby machining the inner hole and the inner spline of the connecting ring 121. The avoidance hole 113 provides a direct channel for machining, without relying on long handle tools or blind hole special tools, thereby reducing the machining difficulty.

[0069] The sealing cover 114 is detachably connected to the shell bottom 112, and the sealing cover 114 seals the avoidance hole 113.

[0070] The shell unit 11 is a core support component of the transmission shaft, and the inside usually needs to be filled with lubricating grease, and needs to be isolated from external dust, water stains and other pollutants.

[0071] Although the avoidance hole 113 is a machining channel, it can achieve the equivalent sealing of the overall structure after being sealed by the sealing cover 114. This design not only solves the problem of damage to the machining channel, but also avoids the leakage of the gap between the mating surfaces caused by the insufficient machining precision of the traditional structure without the avoidance hole 113.

[0072] Furthermore, there are multiple third holes 216. These multiple third holes 216 are arranged axially along the second hole 215. Compared to a single large hole, the axial distribution of multiple third holes 216 avoids excessive weakening of the local structure of the first shaft 211, reduces stress superposition around the third holes 216, and ensures shaft strength. During the assembly stage between the first shaft 211 end face and the bottom wall of the mounting blind hole, the multiple third holes 216 continuously expel residual air from the blind hole, further weakening the airlock effect and reducing assembly resistance.

[0073] Furthermore, 0.4 ≤ D1 / D2 ≤ 0.6. This provides 40%~60% axial space on the side of the connecting ring 121 furthest from the shell unit 11. This ensures sufficient buffer space for air flow within the blind hole when the first shaft 211 is inserted, without causing redundancy in the overall axial dimensions of the connecting ring 121 due to excessively large D2. Moreover, this positions the locking pin 30 in the middle-front section of the connecting ring 121's axial direction, close to the shell unit 11. At this point, the lever arm length from the point of force application of the locking pin 30 to the support end of the shell unit 11 precisely balances force transmission efficiency and stress dispersion. The lever arm is neither too long nor too short, thus extending the fatigue life of the connecting ring 121.

[0074] In other embodiments, such as Figure 4 As shown, the pin-connected drive shaft includes a shaft assembly 20, which includes a second shaft 22 and a second connecting unit 21. The second shaft 22 is coaxially connected to the end of the first shaft 211 away from the ball cage assembly 10. The second shaft 22 can serve as an extension of the first shaft 211, extending the transmission path and allowing the pin-connected drive shaft to adapt to the installation space of different equipment.

[0075] Example 2:

[0076] This application also proposes a method for installing a pin-connected drive shaft, which is applied to any of the pin-connected drive shafts in Embodiment 1; such as Figure 6 As shown, the installation method of the pin-connected drive shaft includes steps S10 to S30.

[0077] Step S10: Insert the first shaft 211 into the mounting blind hole of the connecting ring 121, with one end of the first shaft 211 located on the side of the first hole 125 away from the bottom wall of the mounting blind hole. Air in the mounting blind hole is discharged from the first hole 125. At this time, the first shaft 211 does not completely seal the first hole 125, and air in the mounting blind hole can be directly discharged to the outside through the first hole 125. This stage can quickly release most of the air in the blind hole, avoiding the initial resistance caused by the rapid compression of air when the first shaft 211 is first inserted, laying a low-resistance foundation for subsequent assembly.

[0078] Step S20: Continue inserting the first shaft 211 into the mounting blind hole, and the projection of the end face of the first shaft 211 along the axial direction of the first shaft 211 coincides with the first hole 125, and the air in the mounting blind hole is discharged from the first hole 125. The end face of the first shaft 211 covers the first hole 125 in the circumferential direction, forming a semi-closed exhaust state. Air can still be discharged through the gap between the end face of the first shaft 211 and the first hole 125, but the discharge speed gradually slows down with the increase of the insertion depth. This stage controls the exhaust rhythm, avoids the first shaft 211 from moving due to the air being discharged too fast, and ensures that the air pressure in the blind hole decreases smoothly, so that the insertion process is more stable.

[0079] Step S30: Continue inserting the first shaft 211 into the mounting blind hole, and the end face of the first shaft 211 is located between the first hole 125 and the bottom wall of the mounting blind hole. At this time, the air in the mounting blind hole is not connected with the external environment, and the air pressure in the mounting blind hole is greater than the external air pressure. The first shaft 211 completely covers the first hole 125, and the remaining air in the blind hole is compressed, but because a large amount of air has been discharged in the previous two stages, the amount of remaining air is small, and the increase of air pressure is controllable. The slight air pressure at this time can form a buffer force to avoid damage to the components caused by the first shaft 211 directly impacting the bottom wall of the blind hole, and the reaction force of the air pressure can also assist the first shaft 211 to be accurately positioned.

[0080] Further, the second connecting unit 21 includes a third hole 216;

[0081] As shown in Figure 7 Step S30 includes steps S31 to S32.

[0082] Step S31: Continue inserting the first shaft 211 into the mounting blind hole, and the end face of the first shaft 211 is located between the first hole 125 and the bottom wall of the mounting blind hole, and the air in the mounting blind hole flows from the third hole 216 to the second hole 215, and then is discharged from the first hole 125.

[0083] When the end face of the first shaft 211 enters between the first hole 125 and the bottom wall of the mounting blind hole, if there is no third hole 216, the first shaft 211 will block the direct communication between the first hole 125 and the bottom of the blind hole, causing the air at the bottom of the blind hole to be completely closed and the air pressure to rise sharply. The presence of the third hole 216 provides an alternative channel for the air at the bottom of the blind hole. The bottom air can flow into the second hole 215 through the third hole 216, and then be discharged through the communication gap between the second hole 215 and the first hole 125, even if the end face of the first shaft 211 blocks the direct path between the first hole 125 and the bottom, the air can still be continuously discharged.

[0084] If the air pressure is too high, a larger external force is required to complete the insertion, which can easily cause the end face of the first shaft 211 to collide with the bottom wall of the blind hole or the spline teeth in the connecting ring 121 to deform due to excessive force. The exhaust function of the third hole 216 can reduce the insertion resistance at this stage, and the first shaft 211 can smoothly fit the bottom wall with less external force, avoiding hard contact damage.

[0085] Step S32: The end of the first shaft 211 abuts against the bottom wall of the mounting blind hole, so that the first shaft 211 is completed.

[0086] Those skilled in the art can understand that the above-mentioned embodiments are specific cases for implementing the present disclosure, and in actual application, various changes can be made in form and details without departing from the scope of the present disclosure.

Claims

1. A pin-connected drive shaft, characterized in that The pin connection transmission shaft comprises: The ball cage assembly comprises a shell unit, a first connecting unit; the first connecting unit comprises a connecting ring and a first hole; the connecting ring is connected with one end of the shell unit; the inner hole of the connecting ring and the side wall of the shell unit form a mounting blind hole; the first hole communicates with the mounting blind hole through the side wall of the connecting ring; The second connecting unit comprises a first shaft and a second hole; the first shaft is connected with the connecting ring in the mounting blind hole; the second hole penetrates through the first shaft; The lock pin passes through the first hole and the second hole in turn; Wherein, D1 < D2; D1 is the minimum distance from the first hole to the end of the connecting ring close to the shell unit; D2 is the minimum distance from the first hole to the end of the connecting ring away from the shell unit; The first shaft and the connecting ring are connected in the mounting blind hole by inner spline and outer spline; The inner spline comprises a first inner spline, a second inner spline and a third inner spline; the first inner spline, the second inner spline and the third inner spline are sequentially arranged on the inner circumferential wall of the connecting ring in the direction of the shell unit; The outer spline comprises a first outer spline, a second outer spline and a third outer spline; the first outer spline, the second outer spline and the third outer spline are sequentially arranged on the outer circumferential wall of the first shaft; The first inner spline is matched with the first outer spline; the second inner spline is matched with the second outer spline; the third inner spline is matched with the third outer spline; The first hole is located between the first inner spline and the third inner spline; the second hole is located between the first outer spline and the third outer spline; The maximum gap between the first inner spline and the first outer spline is smaller than the maximum gap between the third inner spline and the third outer spline; or, the interference amount between the first inner spline and the first outer spline is greater than the interference amount of the third inner spline and the third outer spline.

2. The pin connection transmission shaft according to claim 1, wherein the second connecting unit comprises a third hole; the third hole is arranged on the first shaft; one end of the third hole is recessed from the end of the first shaft close to the bottom wall of the mounting blind hole, and the other end extends towards the direction close to the second hole and communicates with the second hole.

3. The pin connection transmission shaft according to claim 1, wherein the maximum gap between the first inner spline and the first outer spline is smaller than the maximum gap between the second inner spline and the second outer spline; or, the interference amount between the first inner spline and the first outer spline is greater than the interference amount of the second inner spline and the second outer spline; The maximum gap between the second inner spline and the second outer spline is smaller than the maximum gap between the third inner spline and the third outer spline; or, the interference amount between the second inner spline and the second outer spline is greater than the interference amount of the third inner spline and the third outer spline.

4. The pin connection transmission shaft according to claim 1, wherein the shell unit comprises a shell ring, a shell bottom, a clearance hole and a sealing cover. ​ ​ ​ The shell bottom is connected with one end of the shell ring and one end of the connecting ring respectively; the inner hole of the connecting ring and the shell bottom form the mounting blind hole; the avoiding hole penetrates the shell bottom along the circumferential direction of the connecting ring; One end of the avoiding hole communicates with the hollow chamber surrounded by the shell ring and the shell bottom, and the other end communicates with the mounting blind hole; the sealing cover is detachably connected with the shell bottom, and the sealing cover seals the avoiding hole.

5. The pin-connected transmission shaft according to claim 2, wherein The number of the third holes is multiple; and the multiple third holes are arranged along the axial direction of the second hole.

6. The pin-connected transmission shaft according to claim 1, wherein 0.4≤D1 / D2≤0.

6.

7. A mounting method of a pin-connected transmission shaft, comprising: The mounting method of the pin-connected transmission shaft is applied to the pin-connected transmission shaft according to any one of claims 1-6; The mounting method of the pin-connected transmission shaft comprises: Inserting the first shaft portion into the mounting blind hole of the connecting ring, and one end of the first shaft is located on the side of the first hole away from the bottom wall of the mounting blind hole, and the air in the mounting blind hole is discharged from the first hole; Continuing to insert the first shaft into the mounting blind hole, and the projection of the end face of the first shaft along the axial direction of the first shaft coincides with the first hole, and the air in the mounting blind hole is discharged from the first hole; Continuing to insert the first shaft into the mounting blind hole until the end of the first shaft abuts against the bottom wall of the mounting blind hole.

8. The mounting method of the pin-connected transmission shaft according to claim 7, wherein The second connecting unit comprises a third hole; Continuing to insert the first shaft into the mounting blind hole until the end of the first shaft abuts against the bottom wall of the mounting blind hole comprises: Continuing to insert the first shaft into the mounting blind hole, and the end face of the first shaft is located between the first hole and the bottom wall of the mounting blind hole, the air in the mounting blind hole flows from the third hole to the second hole, and then is discharged from the first hole; The end of the first shaft abuts against the bottom wall of the mounting blind hole.

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