Hub bearing unit

Abstract

The invention provides a hub bearing unit which comprises a flange outer ring, a flange inner ring and a transmission shaft, the transmission shaft comprises a connecting part and a first spline, the connecting part is inserted into the flange inner ring and fastened through a bolt, the first spline is arranged around the connecting part, a second spline is arranged at the end, facing the transmission shaft, of the flange inner ring, and the second spline is arranged around the connecting part. The flange inner ring comprises an inner hole wall, the first tensioning piece is located on the movement path of the inner hole wall when the flange inner ring and the transmission shaft are assembled, and the first tensioning piece is located on the inner hole wall when the flange inner ring and the transmission shaft are assembled. After the distance between the first spline and the second spline is smaller than the abutting distance, the first spline and the second spline are in interference fit with the inner hole wall. Aiming at the defects in the prior art, the invention provides the hub bearing unit capable of effectively feeding back the spline matching state.

Description

Technical Field

[0001] This invention relates to the field of bearings, and in particular to a hub bearing unit. Background Technology

[0002] Wheel bearing units are a crucial transmission component in automotive systems, bearing the core functions of supporting the vehicle's weight, transmitting rotational torque, and ensuring precise wheel rotation. Their performance and stability directly impact vehicle safety, handling, and comfort. A typical wheel bearing unit includes an outer flange ring, an inner flange ring, a drive shaft, and rolling elements. The connection and fit between the drive shaft and the inner flange ring are critical to the unit's transmission efficiency and lifespan. To achieve torque transmission between the drive shaft and the inner flange ring, spline structures are typically installed on the opposite end faces of both. Power transmission is achieved through the meshing of these splines. However, in current technology, during the assembly of the drive shaft and the inner flange ring, there is a chance that the spline teeth may abut against each other, failing to achieve proper meshing. Furthermore, due to the assembly process of the drive shaft and the inner flange ring... Assembly must be completed in a closed or semi-closed tooling environment, and the spline meshing state of the two parts cannot be directly observed by the naked eye during the assembly process. When there are slight deviations in the assembly operation or minor machining errors in the spline tooth surface, the tooth tip of the drive shaft spline and the tooth tip of the flange inner ring spline are very likely to abut against each other, that is, an abnormal assembly of the top teeth, rather than the tooth surface meshing state expected in the design. Moreover, this top tooth state is difficult to detect in time during the assembly stage. As the vehicle mileage increases, the spline top teeth will be subjected to high-frequency impact loads and torques continuously, and will quickly produce failure phenomena such as tooth tip wear, plastic deformation, or even tooth fracture. Initially, it may manifest as a slight jerking of power transmission. As the damage intensifies, it will eventually lead to a complete interruption of power transmission between the drive shaft and the flange inner ring, causing the vehicle to lose driving power. In severe cases, it may even cause major safety accidents such as loss of wheel control. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a hub bearing unit that effectively provides feedback on the spline fit state.

[0004] To achieve the above objectives, the present invention provides a hub bearing unit, including an outer flange ring, an inner flange ring, and a drive shaft. The drive shaft includes a connecting portion and a first spline. The connecting portion is inserted into the inner flange ring and fastened with bolts. The first spline surrounds the connecting portion. A second spline is provided at the end of the inner flange ring facing the drive shaft. A first annular groove is provided on the connecting portion. A first tensioning member is elastically fitted in the first annular groove. The inner flange ring includes an inner bore wall. The first tensioning member is located on the movement path of the inner bore wall when the inner flange ring and the drive shaft are assembled. During the assembly of the inner flange ring and the drive shaft, the distance between the first spline and the second spline is less than the distance between them when they abut each other, thus forming an interference fit with the inner bore wall.

[0005] The advantages of the above technical solution are as follows: By setting a first annular groove and fitting a first elastic tensioning element at the drive shaft connection, during assembly, when the distance between the first and second splines decreases to less than their abutment distance, the first tensioning element can form an interference fit with the inner wall of the flange inner ring. This allows the first elastic tensioning element, fitted in the first annular groove of the drive shaft connection, to enter the inner wall region of the flange inner ring as the assembly progresses, forming an interference fit with the inner wall. The resistance change generated by this interference fit can be directly transmitted to the assembly operation end, providing the operator with a clear indication that the splines are properly engaged. Conversely, if an abnormality occurs in the top teeth of the first and second splines during assembly—that is, the tooth tips abut against each other and cannot move closer—the relative position of the drive shaft and the inner ring of the flange has not reached the designed engagement depth. The first tensioner is still outside the movement path of the inner hole wall and cannot form an abutment or interference fit with the inner hole wall. No feedback is generated, and the assembly abnormality is judged in time, avoiding blindly tightening the bolts. This design not only eliminates the risk of subsequent tooth surface damage and power interruption caused by the failure to detect the top teeth, but also greatly reduces the reliance on complex testing equipment for assembly, improves assembly efficiency and accuracy, and, together with the bolt fastening structure, further ensures the long-term stability of the connection between the drive shaft and the inner ring of the flange, extending the service life of the wheel hub bearing unit.

[0006] The present invention can be further configured such that: the transmission shaft includes an extension portion extending from the end of the connecting portion, and the first annular groove is disposed in the connecting portion near the extension portion.

[0007] With further design, the extension formed by the drive shaft at the end of the connection can be inserted into the inner ring channel of the flange in the early stage of assembly, which plays a preliminary role in positioning and guiding the insertion direction of the drive shaft. The first annular groove is set in the connection near the extension, which allows the first tensioning member to enter the predetermined path to cooperate with the inner hole wall more accurately based on the guidance of the extension, further improving the stability and accuracy of the assembly process.

[0008] The invention can be further configured such that the extension extends to the area between the radial extension line of the center of the rolling element near the drive shaft and the radial extension line of the rolling element away from the drive shaft.

[0009] By further designing the extension to extend to the point between the radial extension line of the center of the rolling element near the drive shaft and the radial extension line of the rolling element away from the drive shaft, the extension can fit more closely to the structural contour of the inner ring channel of the flange when it is inserted, forming a more precise guiding positioning. Compared with an extension of ordinary length, this can significantly reduce the probability of spline misalignment caused by offset when the drive shaft is inserted, making it easier for the spline to enter the meshing state.

[0010] The present invention can be further configured such that there is a clearance fit between the inner hole wall and the connecting part, and the difference between their diameters is between 0.1 mm and 2 mm.

[0011] By further designing the gap, the presence of the gap avoids the problem of excessive assembly resistance caused by the contact between the inner hole wall and the connecting part due to the tolerance, while maintaining a small gap to facilitate the mating between the inner hole wall and the first tensioning part.

[0012] The present invention can be further configured such that: the inner ring of the flange includes a guide wall and an outer bore wall, the outer bore wall is located at one end of the inner ring of the flange near the drive shaft, and the diameter of the outer bore wall is larger than the diameter of the inner bore wall; the guide wall has an inclined cross-section, and the two ends of the guide wall are respectively connected to the outer bore wall and the inner bore wall; the first tensioning member abuts against the guide wall when the inner ring of the flange and the drive shaft are in the top tooth state.

[0013] By further refining the design, the larger diameter of the outer hole wall creates a "flared" entrance during the initial insertion of the connector, reducing the difficulty of aligning the connector with the inner hole wall and making the insertion smoother. The inclined guide wall further supports the inserted connector, guiding it precisely to the inner hole wall through the slope, reducing offset during insertion, creating more favorable conditions for spline alignment, and significantly improving the convenience and accuracy of assembly. Furthermore, the inclined structure of the guide wall can provide buffer support for the first tensioning member during tooth jacking, preventing the first tensioning member from deforming due to excessive instantaneous force, ensuring its normal subsequent use, and playing a guiding role.

[0014] The present invention can be further configured such that the difference between the outer hole wall diameter and the inner hole wall diameter is greater than or equal to twice the cross-sectional diameter of the first tensioner.

[0015] With further adjustments, from the perspective of the assembly and initial state of the first tensioner, this difference can provide sufficient radial space for the first tensioner, which is fitted into the first annular groove, in the early stage of the connection part being inserted into the inner ring of the flange. This ensures that the first tensioner will not prematurely contact or be squeezed with the outer hole wall when it enters the outer hole wall area with the connection part, thus avoiding deformation of the first tensioner or obstruction of the connection part insertion due to insufficient space. This ensures smoothness in the initial stage of assembly and also reserves reasonable space for the subsequent guidance of the connection part by the guide wall.

[0016] The present invention can be further configured such that the extension extends to the space between the radial extension lines of the two columns of rolling elements.

[0017] With further modifications, the extension extends between the two rows of rolling elements, allowing for more precise alignment with the internal chamber structure of the flange inner ring that matches the rolling elements when the connecting part is inserted into the flange inner ring, thus providing more stable guidance for the drive shaft.

[0018] The present invention can be further configured such that: a second annular groove is provided on the extension portion, a second tensioning member is fitted on the second annular groove, and the first annular groove is provided on the connecting portion near the extension portion.

[0019] By further designing the extension section, a second annular groove is provided and a second tensioning member is fitted onto it. Simultaneously, the first annular groove is positioned near the extension section in the connecting section. During the insertion of the drive shaft into the inner ring of the flange, the second tensioning member in the extension section can initially form a preliminary positioning with the corresponding area of ​​the inner ring of the flange. Combined with the design of the first annular groove being close to the extension section, the first tensioning member can respond more quickly to the spline engagement state. When the spline is not fully engaged or in the top tooth state, the first tensioning member abuts against the guide wall, while the second tensioning member provides feedback in the extension section first. This dual feedback makes the judgment of assembly abnormalities more accurate. When the spline is fully engaged, the first tensioning member forms an interference fit with the inner hole wall to provide feedback of successful installation. Attached Figure Description

[0020] Figure 1 This is a perspective view of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the internal structure of the device in a precisely installed state according to Embodiment 1 of the present invention; Figure 3 This is Embodiment 1 of the present invention. Figure 2 An enlarged view of part a; Figure 4 This is a schematic diagram of the internal structure of the tooth in the first embodiment of the present invention; Figure 5 This is Embodiment 1 of the present invention. Figure 4Enlarged view of section b; Figure 6 This is a schematic diagram of the internal structure of the top tooth in the prior art according to Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the internal structure of the prior art in the precise installation state according to Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the internal structure of the device in the precise installation state according to Embodiment 2 of the present invention; Figure 9 This is Embodiment 2 of the present invention. Figure 8 Enlarged view of section c; Wherein: flange outer ring 1; flange inner ring 2; second spline 21; inner hole wall 22; guide wall 23; outer hole wall 24; drive shaft 3; connecting part 31; first annular groove 311; first spline 32; extension part 33; second annular groove 331; first tensioning element 4; rolling element 5; second tensioning element 6. Detailed Implementation

[0021] An embodiment of the hub bearing unit of the present invention is as follows: Figure 1-5 As shown: The structure includes an outer flange ring 1, an inner flange ring 2, and a drive shaft 3. The drive shaft 3 includes a connecting part 31 and a first spline 32. The connecting part 31 is inserted into the inner flange ring 2 and secured with bolts. The first spline 32 surrounds the connecting part 31. A second spline 21 is provided at one end of the inner flange ring 2 facing the drive shaft 3. A first annular groove 311 is provided on the connecting part 31, and a first elastically fitted first tensioning member 4 is fitted into the first annular groove 311. The inner flange ring 2 includes an inner bore wall 22. The first tensioning member 4... The first tensioner 4 is located on the movement path of the inner hole wall 22 when the inner ring 2 of the flange and the drive shaft 3 are assembled. During the assembly of the inner ring 2 of the flange and the drive shaft 3, the first spline 32 and the second spline 21 are less than the distance between them when they abut each other, and form an interference fit with the inner hole wall 22. In this embodiment, when the tooth is in the top tooth state, the distance between the tooth reference surfaces of the second spline 21 and the first spline 32 is C3, 1.5mm < C3 < 4mm; when the tooth surfaces of the second spline 21 and the first spline 32 are normally meshed, the distance between the tooth reference surfaces C3 ≤ 0.3mm.

[0022] The drive shaft 3 includes an extension portion 33 extending from the end of the connecting portion 31, and the first annular groove 311 is provided in the connecting portion 31 near the extension portion 33.

[0023] The extension 33 extends to the area between the radial extension line of the center of the rolling element 5 near the drive shaft 3 and the radial extension line of the rolling element 5 away from the drive shaft end.

[0024] The inner hole wall 22 and the connecting part 31 are fitted with a clearance, and the difference in their diameters is between 0.1 mm and 2 mm.

[0025] The flange inner ring 2 includes a guide wall 23 and an outer bore wall 24. The outer bore wall 24 is located at one end of the flange inner ring 2 near the drive shaft 3, and the diameter of the outer bore wall 24 is larger than the diameter of the inner bore wall 22. The guide wall 23 has an inclined cross-section, and its two ends are respectively connected to the outer bore wall 24 and the inner bore wall 22. The first tensioning member 4 abuts against the guide wall 23 when the flange inner ring 2 and the drive shaft 3 are in the top tooth state.

[0026] The difference between the diameter of the outer hole wall 24 and the diameter of the inner hole wall 22 is greater than or equal to twice the cross-sectional diameter of the first tensioner 4.

[0027] A second embodiment of the hub bearing unit of the present invention is as follows: Figure 1-5 As shown, the difference from Embodiment 1 is as follows: the extension 33 extends to the space between the radial extension lines of the two columns of rolling elements 5.

[0028] The extension portion 33 is provided with a second annular groove 331, and a second tensioning member 6 is fitted on the second annular groove 331. The first annular groove 311 is provided on the connecting portion 31 near the extension portion.

[0029] The above examples are merely one preferred embodiment of the present invention. Ordinary variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention are all included within the protection scope of the present invention.

Claims

1. A hub bearing unit, comprising an outer flange ring, an inner flange ring, and a drive shaft, the drive shaft comprising a connecting portion and a first spline, the connecting portion being inserted into the inner flange ring and fastened with bolts, the first spline being arranged around the connecting portion, and a second spline being provided at the end of the inner flange ring facing the drive shaft, characterized in that: The connecting part is provided with a first annular groove, and a first tensioning member is elastically fitted in the first annular groove. The flange inner ring includes an inner hole wall. The first tensioning member is located on the movement path of the inner hole wall when the flange inner ring and the drive shaft are assembled. During the assembly of the flange inner ring and the drive shaft, the distance between the first spline and the second spline is less than the distance between them when they abut each other, and the first tensioning member forms an interference fit with the inner hole wall.

2. The hub bearing unit according to claim 1, characterized in that: The drive shaft includes an extension portion extending from the end of the connecting portion, and the first annular groove is provided in the connecting portion near the extension portion.

3. The hub bearing unit according to claim 2, characterized in that: The extension extends to the area between the radial extension line of the center of the rolling element near the drive shaft and the radial extension line of the end of the rolling element away from the drive shaft.

4. The hub bearing unit according to claim 1, 2, or 3, characterized in that: The inner hole wall and the connecting part are fitted with a clearance, and the difference between their diameters is between 0.1 mm and 2 mm.

5. The hub bearing unit according to claim 1, 2, or 3, characterized in that: The flange inner ring includes a guide wall and an outer bore wall. The outer bore wall is located at one end of the flange inner ring near the drive shaft, and the diameter of the outer bore wall is larger than the diameter of the inner bore wall. The guide wall has an inclined cross-section, and its two ends are respectively connected to the outer bore wall and the inner bore wall. The first tensioning member abuts against the guide wall when the flange inner ring and the drive shaft are in the top tooth state.

6. The hub bearing unit according to claim 5, characterized in that: The difference between the outer hole wall diameter and the inner hole wall diameter is greater than or equal to twice the cross-sectional diameter of the first tensioner.

7. The hub bearing unit according to claim 2, characterized in that: The extension portion extends to the space between the radial extension lines of the two rolling elements.

8. The hub bearing unit according to claim 7, characterized in that: The extension portion is provided with a second annular groove, and a second tensioning member is fitted onto the second annular groove. The first annular groove is provided at the connecting portion near the extension portion.

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