Patent Application
20250003451
The present disclosure relates to wheel bearing devices.
A wheel bearing device called a hub unit is used to attach a wheel and a brake disc to a vehicle body of a motor vehicle (see, for example, Patent Document 1). The wheel bearing device includes an inner shaft having a flange portion for mounting the wheel etc.
The flange portion 92 has: a flange base portion 95 continuous with the body portion 91 and having a circular cross section; a plurality of first thick portions 96 formed radially outward of the flange base portion 95 at equal intervals in the circumferential direction and having the bolt holes 93; and thin portions 97 each located between the first thick portions 96 and thinner than the first thick portions 96. The flange base portion 95 has second thick portions 98 located radially inward of the first thick portions 96 and thicker than the first thick portions 96.
When attaching a brake rotor (not shown) to the flange portion 92, it is necessary to temporarily fix the brake rotor with a bolt. Therefore, the flange portion 92 has a tapped hole 99 for fixing a temporary bolt. The tapped hole 99 is formed in a raised portion 94 of the flange portion 92 because the tapped hole 99 needs to have a sufficient fitting length with the bolt. Since the tapped hole 99 is formed in the raised portion 94, the tapped hole 99 is surrounded by a wall-like thick portion.
In the conventional wheel bearing device shown in
It is an object of the present disclosure to allow a tapped hole to have enough strength while reducing an increase in weight of an inner shaft and balancing the weight of the inner shaft in the circumferential direction in a wheel bearing device.
A wheel bearing device of the present disclosure includes: an outer member; an inner member including, on one side in an axial direction of the inner member, a wheel mounting flange having a plurality of bolt holes for fixing to a wheel and a tapped hole for fixing a brake rotor; and a plurality of rolling elements arranged between the outer member and the inner member. The wheel mounting flange includes: thin portions located in a first region that has a through hole extending through the first region in the axial direction and does not have the tapped hole and a second region that has the tapped hole, the first and second regions being regions each located between the bolt holes adjacent to each other in a circumferential direction; a first thick portion including regions around the bolt holes that are raised from the thin portions toward the other side in the axial direction; and a second thick portion that is a region around the tapped hole that is raised from the thin portion in the second region toward the other side in the axial direction.
According to the wheel bearing device of the present disclosure, it is possible to allow the tapped hole to have enough strength while reducing an increase in weight of the inner member and balancing the weight of the inner member in the circumferential direction in the wheel bearing device.
An overview of embodiments of the invention of the present disclosure will be provided below.
(1) A wheel bearing device of the present disclosure includes: an outer member; an inner member including, on one side in an axial direction of the inner member, a wheel mounting flange having a plurality of bolt holes for fixing to a wheel and a tapped hole for fixing a brake rotor; and a plurality of rolling elements arranged between the outer member and the inner member. The wheel mounting flange includes: thin portions located in a first region that has a through hole extending through the first region in the axial direction and does not have the tapped hole and a second region that has the tapped hole, the first and second regions being regions each located between the bolt holes adjacent to each other in a circumferential direction; a first thick portion including regions around the bolt holes that are raised from the thin portions toward the other side in the axial direction; and a second thick portion that is a region around the tapped hole that is raised from the thin portion in the second region toward the other side in the axial direction.
In the wheel bearing device having such a configuration, providing the second thick portion allows the tapped hole to have enough strength, and forming the through hole reduces an increase in weight of the wheel mounting flange and balances the weight of the wheel mounting flange in the circumferential direction. Therefore, according to such a configuration, it is possible to allow the tapped hole to have enough strength while reducing an increase in weight of the inner member and balancing the weight of the inner member in the circumferential direction in the wheel bearing device.
(2) In the wheel bearing device of the present disclosure, the first thick portion preferably includes: an annular base portion located on a radially inner side of the first thick portion; and protruding portions protruding radially outward in a radial pattern from the base portion, the protruding portions being the regions around the bolt holes that are raised from the thin portions toward the other side in the axial direction, and the second thick portion is preferably connected on both sides in the circumferential direction of the second thick portion to the protruding portions. With this configuration, the strength of the second thick portion can be increased. It is therefore possible to reduce distortion of the tapped hole that is caused by the weight of the brake rotor when the brake rotor is temporarily fixed to the wheel mounting flange.
(3) In the wheel bearing device of the present disclosure, the wheel mounting flange includes, as the thin portions in the first region, a first thin portion having a first through hole and a second thin portion having a second through hole with a smaller diameter than the first through hole. With this configuration, the weight of the wheel mounting flange can be balanced in the circumferential direction.
(4) In the wheel bearing device of the present disclosure, the wheel mounting flange preferably has two tapped holes, the first thin portion is preferably located on a side where a circumferential interval between the tapped holes is small, and the second thin portion is preferably located on a side where the circumferential interval between the tapped holes is large. With this configuration, the weight of the wheel mounting flange having the two tapped holes can be balanced in the circumferential direction.
(5) In the wheel bearing device of the present disclosure, the wheel mounting flange preferably has one tapped hole, and the second thin portion is preferably located farther away in the circumferential direction from the second thick portion than the first thin portion is. With this configuration, the weight of the wheel mounting flange having the one tapped hole can be balanced in the circumferential direction.
(6) In the wheel bearing device of the present disclosure, an axial dimension of the second thick portion is preferably smaller than an axial dimension of the first thick portion. With this configuration, an increase in weight of the wheel mounting flange can be reduced.
(7) In the wheel bearing device of the present disclosure, the second thick portion is preferably connected on a radially inner side of the second thick portion to the base portion. With this configuration, the strength of the second thick portion can further be increased.
Hereinafter, the embodiments of the invention of the present disclosure will be described.
The outer ring 12 has a cylindrical outer ring body portion 21 and a fixing flange portion 22 extending radially outward from the outer ring body portion 21. Outer raceway surfaces 12a, 12b are formed on the inner peripheral side of the outer ring body portion 21. The outer ring 12 is attached to the knuckle (not shown) that is a vehicle body-side member by the flange portion 22. The bearing device 10 including the outer ring 12 is thus fixed to the vehicle body. With the bearing device 10 fixed to the vehicle body, the wheel mounting flange portion 27 side of the inner member 11, which will be described later, faces outside the vehicle. That is, the one side in the axial direction where the flange portion 27 is located is the vehicle outer side, and the opposite side, namely the other side in the axial direction, is the vehicle inner side.
The inner member 11 has an inner shaft (hub shaft) 23 and an inner ring 24 attached to the other side in the axial direction of the inner shaft 23.
The inner shaft 23 has a shaft-shaped body portion 26 located radially inward of the outer ring 12, and the flange portion (wheel mounting flange) 27 located on the one side in the axial direction of the body portion 26. The flange portion 27 has a plurality of bolt holes 28 for mounting the wheel. The inner shaft 23 further has a clinched portion 25 for preventing the inner ring 24 from slipping off toward the other side in the axial direction. The centerline of the inner shaft 23 coincides with the centerline CO of the bearing device 10. The flange portion 27 is provided so as to extend radially outward from the one side in the axial direction of the body portion 26. The wheel and a brake rotor (not shown) are attached to a surface on the one side in the axial direction of the flange portion 27 (flange surface 55). The clinched portion 25 is formed to have an increased diameter by plastic deformation of a cylindrical portion 25a. In
The outer peripheral surface of the body portion 26 has a stepped shape. That is, the body portion 26 has a first shaft portion 29 having an inner raceway surface 11a, and a second shaft portion 30 whose outer peripheral surface has a smaller diameter than that of the first shaft portion 29. With the inner ring 24 fitted onto the second shaft portion 30, the cylindrical portion 25a is plastically deformed to form the clinched portion 25 with an increased diameter. The inner ring 24 is thus sandwiched between the first shaft portion 29 and the clinched portion 25.
The inner ring 24 is an annular member and is fitted on and fixed to the second shaft portion 30. The first inner raceway surface 11a is formed on the outer peripheral surface of the first shaft portion 29, and a second inner raceway surface 11b is formed on the outer peripheral surface of the inner ring 24. A plurality of balls 13 is arranged between the outer raceway surface 12a and the inner raceway surface 11a that are located on the one side in the axial direction. A plurality of balls 13 is arranged between the outer raceway surface 12b and the inner raceway surface 11b that are located on the other side in the axial direction.
The inner shaft 23, the inner ring 24, the outer ring 12, and the balls 13 that are constituent members of the bearing device 10 are made of steel (carbon steel, bearing steel). The cage 14 may be made of steel, or may be made of resin.
An annular space K where the balls 13 are disposed is formed between the inner member 11 and the outer ring 12. The first sealing device 15 is provided on the one side in the axial direction of the annular space K, and the second sealing device 16 is provided on the other side in the axial direction of the annular space K. The sealing devices 15, 16 prevent foreign matter from outside from entering the annular space K. The first sealing device 15 has an annular seal member 31 attached to the outer ring 12 and an annular slinger 32 attached along a base portion 35, which will be described later, of the inner shaft 23. Part of the seal member 31 (lip portion 31a) contacts the slinger 32. The first sealing device 15 can thus prevent foreign matter from entering the annular space K from between the flange portion 27 and the outer ring 12.
Each thin portion 34 is provided radially outward of the base portion 35 at a position between the protruding portions 36, 36 that are adjacent to each other in the circumferential direction. The thin portions 34 are thinner than the first thick portion 33. That is, the axial dimension D3 of the thin portions 34 is smaller than the axial dimension D1 of the first thick portion 33 (protruding portions 36) (see
Since the bolt holes 28 are formed in the protruding portions 36, the number of protruding portions 36 is the same as the number of bolt holes 28 (“5” in the first inner shaft 23A). Since each thin portion 34 is provided between the protruding portions 36, 36 that are adjacent to each other in the circumferential direction, the number of thin portions 34 is the same as the number of protruding portions 36 (“5” in the first inner shaft 23A).
The flange portion 27 further includes second thick portions 37. The second thick portions 37 of the first inner shaft 23A are provided in two of the five thin portions 34. That is, a plurality of second thick portions 37 is formed in the flange portion 27 of the present embodiment. The second thick portions 37 are thinner than the first thick portion 33 and thicker than the thin portions 34. That is, the axial dimension D2 of the second thick portions 37 is smaller than the axial dimension D1 of the first thick portion 33 and larger than the axial dimension D3 of the thin portions 34 (D1>D2>D3, see
The flange portion 27 further has tapped holes 38 in the second thick portions 37. The second thick portions 37 are regions around the tapped holes 38 that are raised from third thin portions 34C, which will be described later, toward the other side in the axial direction. The tapped holes 38 are used to temporarily fix the brake rotor, although not shown in the figures. The flange portion 27 of the first inner shaft 23A has two tapped holes 38. In other words, in the first inner shaft 23A, two second thick portions 37 are provided in order to form two tapped holes 38 in the flange portion 27. In the first inner shaft 23A, providing the second thick portions 37 allows the tapped holes 38 to have enough strength.
Each second thick portion 37 is connected on its both sides in the circumferential direction to the protruding portions 36 of the first thick portion 33. Such a second thick portion 37 has increased rigidity compared to the case where the second thick portion 37 is not connected on its both sides in the circumferential direction to the protruding portions 36. In the first inner shaft 23A having such a configuration, the rigidity of the tapped holes 38 is high enough to reduce distortion of the tapped holes 38 that is caused by the weight of the brake rotor, not shown, when the brake rotor is temporarily fixed to the flange portion.
Each second thick portion 37 is further connected on its radial inner side to the base portion 35 of the first thick portion 33. Such a second thick portion 37 has further increased rigidity compared to the case where the second thick portion 37 is not connected on its radial inner side to the base portion 35. In the first inner shaft 23A having such a configuration, it is possible to reliably reduce distortion of the tapped holes 38 that is caused by the weight of the brake rotor, not shown, when the brake rotor is temporarily fixed to the flange portion.
The flange portion 27 further has a plurality of through holes 40. The through holes 40 are holes formed in order to reduce the weight of the flange portion 27 and to balance the weight in the circumferential direction. The through holes 40 include a first through hole 41 and second through holes 42. The first through hole 41 and the second through holes 42 of the present embodiment are formed in the (three) thin portions 34 where the second thick portions 37 are not provided out of the five thin portions 34. In the first inner shaft 23A, the flange portion 27 has one first through hole 41 and two second through holes 42. The second through holes 42 have a smaller diameter than the first through hole 41. In the first inner shaft 23A, the first through hole 41 is large enough that the base portion 35 of the first thick portion 33 is cut, so that the first through hole 41 has a necessary diameter. In the following description, of the thin portions 34, the thin portion 34 where the first through hole 41 is formed is referred to as first thin portion 34A, the thin portions 34 where the second through holes 42 are formed are referred to as second thin portions 34B, and the thin portions 34 where the second thick portions 37 are formed are referred to as third thin portions 34C. All of the first thin portion 34A, the second thin portions 34B, and the third thin portions 34C are the thin portions 34 formed in the regions each located between the bolt holes 28, 28 adjacent to each other in the circumferential direction. The first thin portion 34A and the second thin portions 34B are the thin portions 34 formed in the regions having no tapped hole 38 (first regions) out of the regions each located between the bolt holes 28, 28 adjacent to each other in the circumferential direction. The third thin portions 34C are the thin portions 34 formed in the regions having the tapped holes 38 (second regions) out of the regions each located between the bolt holes 28, 28 adjacent to each other in the circumferential direction.
In the first inner shaft 23A, the second thick portions 37 and the tapped holes 38 are not formed at equal intervals in the circumferential direction in the flange portion 27. Therefore, when considering only the second thick portions 37 and the tapped holes 38 (third thin portions 34C), the weight of the flange portion 27 is not balanced in the circumferential direction. In the first inner shaft 23A, the flange portion 27 has the plurality of thin portions 34 where the through holes 40 are formed (specifically, the first thin portion 34A and the second thin portions 34B) so that the position of the center of gravity of the flange portion 27 is located on the centerline CO. The weight of the flange portion 27 is thus balanced in the circumferential direction. In the first inner shaft 23A, the flange portion 27 has the plurality of types of through holes 40 with different diameters (first through hole 41 and second through holes 42). However, in the bearing device of the present disclosure, all of the plurality of through holes may have the same diameter. In order for the flange portion 27 to have enough rigidity, it is preferable that the portions of the flange portion 27 that are located radially outward of the through holes 40 have a thickness of 4 mm or more in the radial direction.
In the first inner shaft 23A, the one thin portion 34 located on the side where the circumferential interval between the two tapped holes 38, 38 is small is the first thin portion 34A where the first through hole 41 is formed, and the two thin portions 34, 34 located on the side where the circumferential interval between the tapped holes 38, 38 is large are the second thin portions 34B where the second through holes 42 are formed. In the first inner shaft 23A, the weight of the flange portion 27 is balanced in the circumferential direction by arranging the first thin portion 34A and the second thin portions 34B in this manner. In other words, in the first inner shaft 23A, in the case where the second thick portions 37 and the tapped holes 38 (third thin portions 34C) are unevenly distributed in the circumferential direction, the through holes 40 (first through hole 41 and second through holes 42) are formed so as to be unevenly distributed in the circumferential direction, so that the weight of the flange portion 27 is balanced in the circumferential direction. That is, in the first inner shaft 23A, providing the first thin portion 34A and the second thin portions 34B can reduce an increase in weight of the flange portion 27 and balance the weight of the flange portion 27 in the circumferential direction.
As shown in
In the second inner shaft 23B, the first thin portions 34A and the second thin portions 34B are provided in the (four) thin portions 34 other than the third thin portion 34C out of the five thin portions 34. In the second inner shaft 23B, a total of four through holes 40 including two first through holes 41 and two second through holes 42 are formed in the flange portion 27.
In the second inner shaft 23B, the two thin portions 34 located at a small distance from the tapped hole 38 are the first thin portions 34A, and the two thin portions 34 located at a great distance from the tapped hole 38 are the second thin portions 34B. In the second inner shaft 23B, the first thin portions 34A and the second thin portions 34B are arranged in this manner so that the weight of the flange portion 27 is balanced in the circumferential direction. That is, in the second inner shaft 23B, providing the first thin portions 34A and the second thin portions 34B reduces an increase in weight of the flange portion 27 and balances the weight of the flange portion 27 in the circumferential direction.
As shown in
In the third inner shaft 23C, the first thin portions 34A and the second thin portion 34B are provided in the (three) thin portions 34 other than the third thin portion 34C out of the four thin portions 34. In the third inner shaft 23C, a total of three through holes 40 including two first through holes 41 and one second through hole 42 are formed in the flange portion 27.
In the third inner shaft 23C, the two thin portions 34 located at a small distance from the tapped hole 38 are the first thin portions 34A, and the one thin portion 34 located at a great distance from the tapped hole 38 is the second thin portion 34B. In the third inner shaft 23C, the first thin portions 34A and the second thin portion 34B are arranged in this manner so that the weight of the flange portion 27 is balanced in the circumferential direction. That is, in the third inner shaft 23C, providing the first thin portions 34A and the second thin portion 34B reduces an increase in weight of the flange portion 27 and balances the weight of the flange portion 27 in the circumferential direction.
In the inner shaft 23 having four bolt holes 28 like the third inner shaft 23C, it is possible to form two second thick portions 37 and two tapped holes 38 in the thin portions 34 that are 180 degrees out of phase in the circumferential direction. In this case, the weight of the flange portion 27 can be balanced in the circumferential direction by evenly distributing the second thick portions 37 in the circumferential direction of the flange portion 27. In this case, the weight of the flange portion 27 may be reduced by forming the through holes 40 in the remaining two thin portions 34 where the second thick portions 37 and the tapped holes 38 are not formed.
The bearing device 10 according to the embodiments described above includes: the outer ring 12; the inner shaft 23 including, on its one side in the axial direction, the flange portion 27 having the plurality of bolt holes 28 for fixing to the wheel and the tapped hole(s) 38 for fixing a brake rotor; and the plurality of balls 13 arranged between the outer ring 12 and the inner shaft 23. The flange portion 27 includes: the thin portions 34 located in the first regions each having the through hole 40 extending through the first region in the axial direction and having no tapped hole 38 and the second region(s) having the tapped hole 38, the first and second regions being regions each located between the bolt holes 28 adjacent to each other in the circumferential direction; the first thick portion 33 including the regions around the bolt holes 28 that are raised from the thin portions 34 toward the other side in the axial direction; and the second thick portion(s) 37 that is the region(s) around the tapped hole(s) 38 that is raised from the thin portion(s) 34 in the second region toward the other side in the axial direction.
In the bearing device 10 having such a configuration, providing the second thick portion(s) 37 allows the tapped hole(s) 38 to have enough strength, and forming the through holes 40 reduces an increase in weight of the flange portion 27 and balances the weight of the flange portion 27 in the circumferential direction. Therefore, according to such a configuration, it is possible to allow the tapped hole(s) 38 to have enough strength while reducing an increase in weight of the flange portion 27 and balancing the weight of the flange portion 27 in the circumferential direction in the bearing device 10.
In the bearing device 10 according to the embodiments described above, the first thick portion 33 includes: the annular base portion 35 located on the radially inner side; and the protruding portions 36 protruding radially outward in a radial pattern from the base portion 35, the protruding portions 36 being the regions around the bolt holes 28 that are raised from the thin portions 34 toward the other side in the axial direction. The second thick portion(s) 37 is connected on its both sides in the circumferential direction to the protruding portions 36 of the first thick portion 33. With this configuration, the strength of the second thick portion(s) 37 can be increased. It is therefore possible to reduce distortion of the tapped hole(s) 38 that is caused by the weight of the brake rotor when the brake rotor is temporarily fixed to the flange portion 27.
The bearing device 10 according to the embodiments described above includes, as the thin portions 34 in the first regions, the first thin portion(s) 34A having the first through hole 41 and the second thin portion(s) 34B having the second through hole 42 with a smaller diameter than the first through hole 41. With this configuration, the weight of the flange portion 27 can be balanced in the circumferential direction.
The first inner shaft 23A of the bearing device 10 according to the embodiment described above has two tapped holes 38, the first thin portion 34A is located on the side where the circumferential interval between the tapped holes 38 is small, and the second thin portions 34B are located on the side where the circumferential interval between the tapped holes 38 is large. With this configuration, the weight of the flange portion 27 having the two tapped holes 38 can be balanced in the circumferential direction.
The second inner shaft 23B and the third inner shaft 23C of the bearing device 10 according to the embodiments described above have one tapped hole 38, and the second thin portion(s) 34B is located farther away in the circumferential direction from the second thick portion 37 than the first thin portions 34A are. With this configuration, the weight of the flange portion 27 having the one tapped hole 38 can be balanced in the circumferential direction.
In the bearing device 10 according to the embodiments described above, the axial dimension D2 of the second thick portion(s) 37 is smaller than the axial dimension D1 of the first thick portion 33. With this configuration, an increase in weight of the flange portion 27 can be reduced.
In the bearing device 10 according to the embodiments described above, the second thick portion(s) 37 is connected on its radially inner side to the base portion 35 of the first thick portion 33. With this configuration, the strength of the second thick portion(s) 37 can further be increased.
The embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is not limited to the above embodiments, and is intended to include all modifications within the scope equivalent to that of the configurations described in the claims. For example, although the rolling elements are described as the balls 13, the rolling elements may be rollers (tapered rollers).
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/022104 | 6/10/2021 | WO |
