A driveshaft assembly

Abstract

The present application relates to the technical field of transmission shaft, in particular to a kind of transmission shaft assembly.The transmission shaft assembly includes main transmission shaft, sliding shaft, breathing valve.The main transmission shaft includes shaft tube and spline sleeve, coaxial and fixedly connected;Sliding shaft includes axle fork and spline shaft, fixedly connected, spline shaft and spline sleeve slidingly connected.The breathing valve contains fixed sleeve, sliding sleeve, sliding block, first elastic member, second elastic member;Fixed sleeve connects shaft tube, sliding sleeve slidingly connects first sleeve, there is first ventilation passage between them, first elastic member drives it away from the inner cavity of shaft tube;Sliding block slides in second sleeve, there is second ventilation passage between them;Second ventilation passage cross-sectional area is less than first ventilation passage, second elastic member is used to drive sliding block to move towards the inner cavity of shaft tube, and each blocking portion projection at least partially overlaps.In this way, the problem of dust invasion and lubricating medium leakage in transmission shaft inner cavity is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transmission shaft, in particular to a transmission shaft assembly. BACKGROUND

[0002] The current transmission shaft assembly is a key component for realizing power transmission and motion conversion, and is widely used in automobile transmission system, engineering machinery transmission mechanism and industrial equipment transmission device, etc. The transmission shaft assembly includes a spline pair, which includes a spline shaft and a spline sleeve. The spline shaft and the spline sleeve realize stable transmission of torque through tooth surface engagement, ensuring that each executing component of the equipment moves along the preset trajectory.

[0003] However, the spline pair needs to realize the combined motion of axial displacement and circumferential rotation with the operation of the equipment. The inner cavity of the shaft tube connected with the spline sleeve changes dynamically with the relative axial motion of the spline shaft and the spline sleeve. Therefore, the shaft tube needs to be kept unobstructed with the outside world, which is easy to cause dust to enter the shaft tube and cause wear, and also causes the lubricating medium in the shaft tube to be lost quickly. SUMMARY

[0004] To solve the problems of dust invasion and lubricating medium leakage in the transmission shaft inner cavity, the present application provides a transmission shaft assembly, which comprises:

[0005] A main transmission shaft, which comprises a shaft tube and a spline sleeve; the shaft tube and the spline sleeve are coaxial and fixedly connected;

[0006] A sliding shaft, which comprises a shaft fork and a spline shaft; the shaft fork and the spline shaft are fixedly connected; the spline shaft and the spline sleeve are slidingly connected;

[0007] A breathing valve, comprising a fixed sleeve, a sliding sleeve, a sliding block, a first elastic element, and a second elastic element; the fixed sleeve is fixedly connected to the shaft tube; the fixed sleeve includes a first sleeve and a first blocking part fixedly connected; the sliding sleeve includes a second sleeve, a second blocking part, and a third blocking part fixedly connected; the second sleeve slidably passes through the first sleeve; an annular first ventilation channel is formed between the outer wall of the second sleeve and the inner wall of the first sleeve; the projections of the first blocking part and the second blocking part along the axial direction of the fixed sleeve at least partially overlap; the second blocking part is located at the first blocking part. The first elastic element is positioned on the side facing the inner cavity of the shaft tube; the second elastic element is used to drive the second sleeve to move away from the inner cavity of the shaft tube; the sliding block is slidably disposed inside the second sleeve; an annular second ventilation channel is formed between the sliding block and the inner wall of the first sleeve; the projection of the third blocking part along the axial direction of the second sleeve partially overlaps with the sliding block; the third blocking part is located on the side of the sliding block closer to the inner cavity of the shaft tube; the second elastic element is used to drive the sliding block to move toward the inner cavity of the shaft tube; the cross-sectional area of ​​the second ventilation channel is smaller than the cross-sectional area of ​​the first ventilation channel.

[0008] In some embodiments, the breather valve is located at the end of the shaft tube away from the spline sleeve; the first sleeve and the second sleeve are coaxial with the shaft tube.

[0009] In some embodiments, the fixing sleeve further includes a protective cover; the protective cover covers the end of the fixing sleeve facing the inner cavity of the shaft tube; the second blocking part is movable within the protective cover; the projection of the second sleeve along its own axial direction is located on the wall of the protective cover; there is a gap between the inner peripheral wall of the protective cover and the sliding block; and a vent hole is provided on the circumferential wall of the protective cover.

[0010] In some embodiments, the vent extends from the outer wall of the protective cover to the inner wall in a direction inclined toward the first blocking portion.

[0011] In some embodiments, the first blocking portion has a first abutting surface; the second blocking portion has a second abutting surface, and the first abutting surface and the second abutting surface can abut or separate during the sliding process of the sliding sleeve; when the first abutting surface and the second abutting surface are separated, an air intake channel is formed between the first abutting surface and the second abutting surface; the air intake channel is directly connected to the vent hole and both have the same orientation.

[0012] In some embodiments, the first blocking portion is annular; the first abutting surface is conical; the second blocking portion is annular; and the second abutting surface is conical.

[0013] In some embodiments, the protective cover is fixedly connected to the first abutment surface; the vent extends through the first abutment surface.

[0014] In some embodiments, the opening diameter of the vent hole on the inner wall of the protective cover is smaller than the length of the second blocking portion along the axial direction of the second sleeve.

[0015] In some embodiments, a plurality of vents are provided; the plurality of vents are distributed around the axis of the protective cover.

[0016] In some embodiments, when the first blocking part and the second blocking part are in contact, the distance between the sliding sleeve and the protective cover along the axial direction of the fixed sleeve is less than 50% of the telescopic length range of the first elastic member.

[0017] To solve the problems of dust intrusion and lubrication medium leakage in the drive shaft cavity, the present invention has the following advantages:

[0018] By incorporating a breather valve, the internal cavity of the driveshaft assembly is dynamically opened and closed, ensuring a sealed environment within the main driveshaft cavity when there is no relative axial movement between the main driveshaft and the sliding shaft. This minimizes dust intrusion and lubricant leakage. During operation, the breather valve restricts the opening area and airflow path between the main driveshaft and the outside environment, further inhibiting dust intrusion and lubricant leakage. The relative positions of the first and second blocking parts and the sliding block ensure that the first vent is for external airflow entering the shaft tube cavity, while the second vent is for exhausting air from the shaft tube cavity. The cross-sectional area of ​​the second vent is smaller than that of the first vent, reducing the risk of lubricant leakage. Furthermore, the first vent is an annular structure with a larger diameter than the second vent, resulting in a more dispersed opening in the first vent, further preventing impurities from entering and reducing the risk of dust intrusion. This ultimately extends the service life of the driveshaft assembly. Attached Figure Description

[0019] Figure 1 A schematic diagram of a driveshaft assembly according to one embodiment is shown;

[0020] Figure 2 It shows Figure 1 A magnified view of part A of the drive shaft assembly in the diagram.

[0021] Reference numerals: Main drive shaft 10; Shaft tube 11; Spline sleeve 12; Sliding shaft 20; Shaft fork 21; Spline shaft 22; Breathing valve 30; Fixed sleeve 31; First sleeve 311; First blocking part 312; Protective cover 313; First abutment surface 314; Vent hole 315; Sliding sleeve 32; Second sleeve 321; Second blocking part 322; Third blocking part 323; Fourth blocking part 324; Second abutment surface 325; Sliding block 33; First elastic element 34; Second elastic element 35; First ventilation channel 36; Second ventilation channel 37. Detailed Implementation

[0022] 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.

[0023] 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.

[0024] The driveshaft assembly is a key component for power transmission and motion conversion, widely used in automotive transmission systems, engineering machinery transmission mechanisms, and industrial equipment transmission devices. The driveshaft assembly includes a splined pair, consisting of a splined shaft and a splined sleeve. These two components mesh with their teeth to achieve stable torque transmission, ensuring that each actuator moves along a preset trajectory. However, the splined pair needs to achieve a combination of axial displacement and circumferential rotation as the equipment operates. The inner cavity of the shaft tube connected to the splined sleeve dynamically changes with the relative axial movement of the splined shaft and sleeve. Therefore, the shaft tube needs to remain unobstructed from the outside environment. This makes it easy for dust to enter the shaft tube, leading to wear, and also causes rapid loss of the lubricating medium within the shaft tube.

[0025] In this embodiment, to solve the above problems, this application provides a drive shaft assembly, such as... Figure 1 As shown, the drive shaft assembly includes a main drive shaft 10, a sliding shaft 20, and a breather valve 30.

[0026] The main drive shaft 10 includes a shaft tube 11 and a spline sleeve 12. The shaft tube 11 and the spline sleeve 12 are coaxial and fixedly connected. This fixed connection ensures the overall transmission performance of the main drive shaft 10 and avoids additional vibration caused by eccentricity during transmission. Furthermore, the fixed connection ensures stable power transmission and guarantees the reliability of the drive shaft assembly.

[0027] The sliding shaft 20 includes a shaft fork 21 and a splined shaft 22. The shaft fork 21 and the splined shaft 22 are fixedly connected to each other to prevent power loss due to loosening during power transmission. At the same time, the splined shaft 22 is slidably connected to the splined sleeve 12, which enables axial relative displacement between the main drive shaft 10 and the sliding shaft 20.

[0028] The breather valve 30 includes a fixed sleeve 31, a sliding sleeve 32, a sliding block 33, a first elastic element 34, and a second elastic element 35. The fixed sleeve 31 is fixedly connected to the shaft tube 11, thus achieving stable installation of the breather valve 30 and ensuring stable airflow during the movement of the drive shaft assembly.

[0029] The fixed sleeve 31 includes a first sleeve 311 and a first blocking part 312 that are fixedly connected. The sliding sleeve 32 includes a second sleeve 321, a second blocking part 322, and a third blocking part 323 that are fixedly connected.

[0030] The second sleeve 321 is slidably inserted inside the first sleeve 311. An annular first ventilation channel 36 is formed between the outer wall of the second sleeve 321 and the inner wall of the first sleeve 311. The first ventilation channel 36 enables the inner cavity of the shaft tube 11 to communicate with the outside.

[0031] The projections of the first blocking part 312 and the second blocking part 322 along the axial direction of the fixed sleeve 31 at least partially overlap, so that when the sliding sleeve 32 moves toward the fixed sleeve 31 axially, the first blocking part 312 can contact a portion of the area of ​​the second blocking part 322, thereby limiting the range of the sliding sleeve 32's movement toward the fixed sleeve 31 and preventing excessive movement of the component from causing structural damage.

[0032] The second blocking part 322 is located on the side of the first blocking part 312 facing the inner cavity of the shaft tube 11. When the sliding shaft 20 slides towards the main drive shaft 10, the first blocking part 312 limits the second blocking part 322, thereby limiting the movement between the fixed sleeve 31 and the sliding sleeve 32 and preventing the sliding sleeve 32 from moving too far, which could cause the breathing valve 30 to malfunction. When the sliding shaft 20 moves away from the inner cavity of the shaft tube 11, the first elastic element 34 drives the second sleeve 321 to move away from the inner cavity of the shaft tube 11 for resetting. The sliding block 33 is slidably disposed inside the second sleeve 321, forming an annular second ventilation channel 37 between the sliding block 33 and the inner wall of the first sleeve 311. When the sliding shaft 20 moves towards the main drive shaft 10, the compression of the gas and grease in the inner cavity of the shaft tube 11 causes the sliding block 33 to move away from the inner cavity of the shaft tube 11, thus enabling the air in the inner cavity of the shaft tube 11 to communicate with the outside.

[0033] The projection of the third blocking part 323 along the axial direction of the second sleeve 321 partially overlaps with the sliding block 33. The third blocking part 323 is located on the side of the sliding block 33 closer to the inner cavity of the shaft tube 11. In this way, the third blocking part 323 limits the movement stroke of the sliding block 33, preventing excessive movement of the sliding block 33 from damaging the structure of the breathing valve 30. At the same time, when the sliding shaft 20 moves away from the main drive shaft 10, the combined action of the sliding block 33 and the third blocking part 323 can prevent the outside from communicating with the inner cavity of the shaft tube 11 through the second ventilation channel 37.

[0034] The second elastic element 35 is used to drive the sliding block 33 to move toward the inner cavity of the shaft tube 11. When the pressure in the cavity of the shaft tube 11 is large, the sliding block 33 will move away from the inner cavity of the shaft tube 11. When the pressure in the inner cavity of the shaft tube 11 decreases, the sliding block 33 can be reset by the second elastic element 35, that is, the sliding block 33 abuts against the third blocking part 323.

[0035] By setting a breather valve 30, the internal cavity of the drive shaft assembly is dynamically opened and closed, ensuring that the internal cavity of the main drive shaft 10 remains sealed when there is no relative axial movement between the main drive shaft 10 and the sliding shaft 20, thereby minimizing dust intrusion and lubricant leakage. When the drive shaft assembly is in operation, the breather valve 30 limits the opening area and airflow path of the main drive shaft 10 to the outside, thus inhibiting dust intrusion and lubricant leakage. The relative positions of the first blocking part 312, the second blocking part 322, and the sliding block 33 ensure that the first venting channel 36 is the airflow channel for external airflow into the internal cavity of the shaft tube 11, and the second venting channel 37 is the airflow channel for exhaust from the internal cavity of the shaft tube 11. The cross-sectional area of ​​the second venting channel 37 is smaller than that of the first venting channel 36, thereby reducing the risk of lubricant leakage. Furthermore, the cross-sectional area of ​​the first ventilation channel 36 is an annular shape with a larger diameter than that of the second ventilation channel 37. This makes the openings of the first ventilation channel 36 more dispersed, further preventing impurity particles from entering the first ventilation channel 36 and reducing the risk of dust intrusion. This, in turn, ensures the service life of the drive shaft assembly.

[0036] This application adds a breather valve 30, so that when the sliding shaft 20 moves toward the main drive shaft 10, the pressure inside the shaft tube 11 is greater than the external pressure, thus forming a one-way flow from the inside to the outside. When the sliding shaft 20 moves away from the main drive shaft 10, the external pressure is greater than the pressure inside the shaft tube 11, thus forming a one-way flow from the outside to the inside.

[0037] Furthermore, such as Figure 1 As shown, the breather valve 30 is located at the end of the shaft tube 11 away from the spline sleeve 12. This ensures that the spline shaft 22 and spline sleeve 12 are not affected by the installation position of the breather valve 30 during axial sliding. This position also facilitates the assembly and subsequent maintenance of the breather valve 30, reducing interference with the core transmission components of the drive shaft. The first sleeve 311 and the second sleeve 321 are coaxial with the shaft tube 11. This allows the pressure inside the shaft tube 11 to be uniformly transmitted axially to the breather valve 30, avoiding airflow turbulence caused by misalignment and ensuring stable operation of the drive shaft assembly. Simultaneously, it ensures that the breather valve 30 does not affect the dynamic balance of the drive shaft assembly, and that changes in the speed of the drive shaft assembly do not affect the working pressure.

[0038] Furthermore, such as Figure 2As shown, the fixed sleeve 31 also includes a protective cover 313. The protective cover 313 covers the end of the fixed sleeve 31 facing the inner cavity of the shaft tube 11. The second blocking part 322 is movable within the protective cover 313. By changing the movement path of the grease through the protective cover 313, the grease in the inner cavity of the shaft tube 11 is prevented from directly entering the second channel and flowing to the outside. This reduces the risk of grease leakage and ensures the long-term stable operation of the breather valve 30. At the same time, the projection of the second sleeve 321 along its own axial direction is located on the wall of the protective cover 313, ensuring that the protective cover 313 can completely cover the end of the second sleeve 321 facing the inner cavity of the shaft tube 11, reducing the area of ​​grease entering the second ventilation channel 37. Furthermore, there is a gap between the inner peripheral wall of the protective cover 313 and the sliding block 33, ensuring that when the sliding shaft 20 moves in the direction of the main drive shaft 10, the gas can move the sliding block 33 away from the inner cavity of the shaft tube 11 through the gap. The sliding block 33 can slide smoothly to adjust the communication between the second ventilation channel 37 and the inner cavity of the shaft tube 11. Vent holes 315 are provided on the circumferential wall of the protective cover 313. Vent holes 315 alter the movement path of gas and grease, preventing direct entry into the second venting channel 37 and thus grease leakage. Simultaneously, vent holes 315 allow communication between the inner cavity of the shaft tube 11 and the outside environment, preventing the protective cover 313 from blocking the second venting channel 37 and the first venting channel 36, which could cause excessive pressure within the shaft tube 11 and damage to components. This ensures the necessary airflow during the movement of the drive shaft assembly.

[0039] Furthermore, such as Figure 2 As shown, when the sliding shaft 20 moves toward the main drive shaft 10, the grease flows through the vent 315 to the outer peripheral walls of the first blocking part 312 and the second blocking part 322, causing the grease to adhere to the surface of the first blocking part 312. Therefore, the extension direction of the vent 315 from the outer wall to the inner wall of the protective cover 313 is tilted toward the direction closer to the first blocking part 312. In this way, when the sliding sleeve 32 and the fixed sleeve 31 move relative to each other, and the first venting channel 36 connects with the inner cavity of the shaft tube 11, the grease adhering to the first blocking part 312 can be blown back into the inner cavity of the shaft tube 11 by external pressure, reducing grease leakage. At the same time, it ensures the unobstructed flow of the vent 315 and avoids abnormal pressure increase in the inner cavity due to blockage of the vent 315, which could lead to grease leakage.

[0040] Furthermore, such as Figure 2As shown, the first blocking part 312 has a first abutting surface 314, and the second blocking part 322 has a second abutting surface 325. During the sliding process of the sliding sleeve 32, the first abutting surface 314 and the second abutting surface 325 can abut or separate. When the first abutting surface 314 and the second abutting surface 325 are separated, an air intake channel is formed between the first abutting surface 314 and the second abutting surface 325. The air intake channel and the vent 315 are directly opposite each other and have the same orientation. In this way, when the external pressure is greater than the pressure inside the shaft tube 11, that is, when the sliding shaft 20 moves away from the breather valve 30, the air pressure in the first vent 36 can blow the grease attached to the first abutting surface 314 back into the shaft tube 11, ensuring the lubrication effect of the drive shaft assembly.

[0041] With the first contact surface 314 and the second contact surface 325 in contact, the movement stroke of the sliding sleeve 32 can be precisely limited, preventing damage to the components caused by excessive movement of the sliding sleeve 32. At the same time, it ensures that the gas and grease inside the shaft tube 11 can only flow through the vent 315 to the gap between the inner peripheral wall of the protective cover 313 and the sliding block 33. By applying pressure, the sliding block 33 is moved away from the inner cavity of the shaft tube 11, so that the inner cavity of the shaft tube 11 is connected to the second venting channel 37, realizing the one-way flow of the breathing valve 30.

[0042] Furthermore, such as Figure 2 As shown, the first blocking part 312 is annular. The first abutting surface 314 is conical, the second blocking part 322 is annular, and the second abutting surface 325 is conical. By ensuring that both the first blocking part 312 and the second blocking part 322 are annular, a circumferentially uniform fit is formed, preventing uneven force distribution due to local structural asymmetry during contact or separation. This ensures the stability and coaxiality of the sliding sleeve 32 during axial movement and prevents poor contact at the abutting surfaces due to misalignment. Furthermore, the conical design of the first abutting surface 314 and the second abutting surface 325 increases the contact area with the second abutting surface 325 compared to a planar structure, improving the sealing effect during contact. Furthermore, it can be matched with the inclined direction of the vent hole 315 to ensure that the ventilation of the second ventilation channel 37 can be directly through the conical design of the first contact surface 314 and the second contact surface 325 opposite to the vent hole 315, ensuring that the grease attached to the first contact part can be blown back into the inner cavity of the shaft tube 11, ensuring the smooth sliding of the main drive shaft 10 and the sliding shaft 20.

[0043] Furthermore, such as Figure 2As shown, the protective cover 313 is fixedly connected to the first abutment surface 314, thereby ensuring the stability of the connection between the protective cover 313 and the first abutment surface 314 and preventing the protective cover 313 from loosening or falling off due to vibration, impact, or other factors during the operation of the drive shaft. The vent 315 extends through the first abutment surface 314, forming a smooth airflow path from the air intake channel to the first abutment surface 314 and then to the vent 315. This reduces airflow resistance during transmission, improves the response speed of air pressure regulation within the shaft tube 11, and prevents lubricating grease leakage caused by pressure buildup in the internal cavity due to obstructed airflow. This ensures the smooth sliding of the main drive shaft 10 and the sliding shaft 20, guaranteeing the reliable operation of the drive shaft assembly.

[0044] Furthermore, such as Figure 2 As shown, the opening diameter of the vent 315 on the inner wall of the protective cover 313 is smaller than the axial length of the second blocking part 322 along the second sleeve 321. This ensures that when the second blocking part 322 moves within the protective cover 313, its axial length always partially blocks the opening of the inner wall of the vent 315, preventing excessive gaps between the first blocking part 312 and the second blocking part 322. This reduces the probability of foreign objects directly entering the breather valve 30 through the vent 315 and also reduces the risk of lubricating grease in the inner cavity of the shaft tube 11 rapidly overflowing through the opening of the vent 315 when the air pressure fluctuates. This helps improve the protection and oil control effect of the breather valve 30, ensuring that the breather valve 30 can stably regulate the air pressure in the inner cavity of the shaft tube 11 under different operating conditions. This further ensures the smooth sliding of the main drive shaft 10 and the sliding shaft 20, reduces spline pair failure caused by foreign object intrusion or grease leakage, and maintains the stable operation of the drive shaft assembly.

[0045] Furthermore, such as Figure 2 As shown, multiple vent holes 315 are provided. These multiple vent holes 315 are distributed around the axis of the protective cover 313. This increases the total airflow between the inner cavity of the shaft tube 11 and the outside environment, preventing venting failure due to blockage of a single vent hole 315, ensuring the continuity of the air pressure regulation function, and preventing abnormal pressure increases or decreases in the inner cavity of the shaft tube 11 due to insufficient airflow. This, in turn, ensures the long-term stable operation of the drive shaft assembly.

[0046] Furthermore, such as Figure 2As shown, when the first blocking part 312 and the second blocking part 322 are in contact, the distance between the sliding sleeve 32 and the protective cover 313 along the axial direction of the fixed sleeve 31 is less than 50% of the telescopic length range of the first elastic member 34. This should be understood as preventing the first elastic member 34 from entering its limit working state due to excessive stretching or compression, extending the service life of the first elastic member 34, and preventing it from failing due to elastic fatigue, which would cause the sliding sleeve 32 to be unable to move normally. At the same time, sufficient telescopic margin can ensure that when the air pressure in the inner cavity of the shaft tube 11 changes, the first elastic member 34 can quickly drive the sliding sleeve 32 to move axially, realizing the timely separation or contact between the first contact surface 314 and the second contact surface 325, avoiding the air pressure adjustment not being timely due to the lag in the response of the elastic member, which would cause the lubricating grease to leak, ensuring the rapid response capability and long-term working stability of the breather valve 30 to air pressure changes, further assisting in controlling the leakage of lubricating grease, thereby ensuring the smooth sliding of the main drive shaft 10 and the sliding shaft 20, and maintaining the reliability of the drive shaft assembly.

[0047] In some other embodiments, the sliding sleeve 32 further includes a fourth blocking portion 324, which is connected to the end of the second sleeve 321 away from the protective cover 313. One end of the first elastic member 34 is connected to the fourth blocking portion 324, and the other end is connected to the first blocking portion 312.

[0048] 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 drive shaft assembly, characterized in that, The drive shaft assembly includes: A main drive shaft, comprising a shaft tube and a splined sleeve; the shaft tube and the splined sleeve are coaxial and fixedly connected. A sliding shaft, comprising a shaft fork and a splined shaft; the shaft fork is fixedly connected to the splined shaft; the splined shaft is slidably connected to the splined sleeve; A breathing valve includes a fixed sleeve, a sliding sleeve, a sliding block, a first elastic element, and a second elastic element; the fixed sleeve is fixedly connected to the shaft tube; the fixed sleeve includes a first sleeve and a first blocking part fixedly connected; the sliding sleeve includes a second sleeve, a second blocking part, and a third blocking part fixedly connected; the second sleeve slidably passes through the first sleeve; an annular first ventilation channel is formed between the outer wall of the second sleeve and the inner wall of the first sleeve; the projections of the first blocking part and the second blocking part along the axial direction of the fixed sleeve at least partially overlap; the second blocking part is located on the side of the first blocking part facing the inner cavity of the shaft tube; The first elastic element is used to drive the second sleeve to move away from the inner cavity of the shaft tube; the sliding block is slidably disposed inside the second sleeve; an annular second ventilation channel is formed between the sliding block and the inner wall of the first sleeve; the projection of the third blocking part along the axial direction of the second sleeve partially overlaps with the sliding block; the third blocking part is located on the side of the sliding block closer to the inner cavity of the shaft tube; the second elastic element is used to drive the sliding block to move toward the inner cavity of the shaft tube; the cross-sectional area of ​​the second ventilation channel is smaller than the cross-sectional area of ​​the first ventilation channel; The fixed sleeve also includes a protective cover; the protective cover is provided on the end of the fixed sleeve facing the inner cavity of the shaft tube; the second blocking part is movable in the protective cover; the projection of the second sleeve along its own axial direction is located on the wall of the protective cover; there is a gap between the inner peripheral wall of the protective cover and the sliding block; and a vent hole is provided on the circumferential wall of the protective cover. The first blocking part has a first abutting surface; the second blocking part has a second abutting surface, and the first abutting surface and the second abutting surface can abut or separate during the sliding process of the sliding sleeve; when the first abutting surface and the second abutting surface are separated, an air intake channel is formed between the first abutting surface and the second abutting surface; the air intake channel is directly connected to the vent and the two face the same direction.

2. The drive shaft assembly according to claim 1, characterized in that, The breather valve is located at the end of the shaft tube away from the spline sleeve; the first sleeve and the second sleeve are coaxial with the shaft tube.

3. A drive shaft assembly according to claim 1, characterized in that, The vent extends from the outer wall of the protective cover to the inner wall in a direction that is inclined toward the first blocking part.

4. A drive shaft assembly according to claim 1, characterized in that, The first blocking part is annular; the first abutting surface is conical; the second blocking part is annular; the second abutting surface is conical.

5. A drive shaft assembly according to claim 4, characterized in that, The protective cover is fixedly connected to the first contact surface; the vent extends through the first contact surface.

6. A drive shaft assembly according to claim 5, characterized in that, The opening diameter of the vent hole on the inner wall of the protective cover is smaller than the length of the second blocking part along the axial direction of the second sleeve.

7. A drive shaft assembly according to claim 4, characterized in that, The ventilation holes are provided in multiple ways; the multiple ventilation holes are distributed around the axis of the protective cover.

8. A drive shaft assembly according to claim 1, characterized in that, When the first blocking part and the second blocking part are in contact, the distance between the sliding sleeve and the protective cover along the axial direction of the fixed sleeve is less than 50% of the telescopic length range of the first elastic member.

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