Patent Grant
10086649
The present invention relates to a bearing device for a wheel configured to rotatably support a driving wheel (front wheel of a front-engine front-drive (FF) vehicle, rear wheel of a front-engine rear-drive (FR) vehicle, and all wheels of a four-wheel drive (4WD) vehicle) with respect to a suspension device for an automobile, for example.
As illustrated in
The hub wheel 101 has an inner raceway surface 108 on an outboard side formed on an outer peripheral surface thereof, and includes a wheel mounting flange 109 for allowing a wheel (not shown) to be mounted thereto. Hub bolts 110 for fixing a wheel disc are equiangularly embedded in the wheel mounting flange 109. The inner ring 102 is fitted to a small-diameter step portion 111 formed on an outer peripheral surface of the hub wheel 101 on an inboard side, and an inner raceway surface 112 on the inboard side is formed on an outer peripheral surface of the inner ring 102. On an inner peripheral surface of a shaft hole of the hub wheel 101, a female spline 113 for coupling the constant velocity universal joint 107 to allow torque transmission therebetween is formed.
The inner ring 102 is press-fitted with adequate interference for the purpose of preventing creep. The inner raceway surface 108 on the outboard side that is formed on the outer peripheral surface of the hub wheel 101 and the inner raceway surface 112 on the inboard side that is formed on the outer peripheral surface of the inner ring 102 constitute double-row inner raceway surfaces. The inner ring 102 is press-fitted into the small-diameter step portion 111 of the hub wheel 101, and an end portion of the small-diameter step portion 111 is crimped outward. As a result, the inner ring 102 is retained by a crimped portion 114 thus formed and integrated with the hub wheel 101, to thereby apply preload to the wheel bearing 106.
The outer ring 105 has double-row outer raceway surfaces 115 and 116 formed on an inner peripheral surface thereof and opposed to the inner raceway surfaces 108 and 112 of the hub wheel 101 and the inner ring 102. The outer ring 105 has a vehicle body mounting flange 117 for mounting the wheel bearing 106 to a vehicle body (not shown) on an outer peripheral surface thereof. The vehicle body mounting flange 117 is fixed to a knuckle extending from a suspension device (not shown) of the vehicle body with a bolt or the like by using a mounting hole 118.
The wheel bearing 106 has a double-row angular ball bearing structure. That is, the balls 103 and 104 are interposed between the inner raceway surfaces 108 and 112 formed on the outer peripheral surfaces of the hub wheel 101 and the inner ring 102 and the outer raceway surfaces 115 and 116 formed on the inner peripheral surface of the outer ring 105. Then, the balls 103 and 104 in respective rows are equiangularly supported by cages 119 and 120.
At opening portions on both ends of the wheel bearing 106, a pair of seals 121 and 122 for sealing annular spaces between the outer ring 105 and the hub wheel 101 and between the outer ring 105 and the inner ring 102 are fitted to the inner diameter at both end portions of the outer ring 105. With this, leakage of lubricant such as grease filled inside and entrance of water and foreign matter from the outside are prevented.
The bearing device for a wheel is configured by coupling an outer joint member 123 of the constant velocity universal joint 107 to the hub wheel 101. The outer joint member 123 includes a cup-shaped mouth section 124 that accommodates internal components (not shown) such as an inner joint member, balls, and a cage, and a stem section 125 that integrally extends from the mouth section 124 in an axial direction. On an outer peripheral surface of the stem section 125, a male spline 126 for coupling the stem section 125 to the hub wheel 101 to allow torque transmission therebetween is formed.
The stem section 125 of the outer joint member 123 is press-fitted into the shaft hole of the hub wheel 101 so that a nut 127 is threadedly engaged with a male thread portion 129 formed at an end portion of the stem section 125. Then, by fastening the nut 127 in a state of being locked to an end surface of the hub wheel 101, the constant velocity universal joint 107 is fixed to the hub wheel 101. A shoulder portion 128 of the outer joint member 123 is brought into abutment against the crimped portion 114 of the hub wheel 101 by a fastening force (axial force) of the nut 127. In this manner, the male spline 126 of the stem section 125 and the female spline 113 of the hub wheel 101 are fitted to each other. As a result, the torque transmission from the constant velocity universal joint 107 to the wheel bearing 106 is enabled.
In the bearing device for a wheel described above, the crimped portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123, which is opposed to the crimped portion 114, are in a state of abutment against each other by the fastening force (axial force) of the nut 127. Thus, when a rotational torque is applied from the constant velocity universal joint 107 to the wheel bearing 106 that is in a stationary state at the start of the vehicle, the rotational torque is to be transmitted from the outer joint member 123 to the hub wheel 101 through an intermediation of the female spline 113 and the male spline 126. At this time, however, sudden slippage occurs between the crimped portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123 due to torsion of the outer joint member 123. Stick-slip noise generally referred to as squeaking noise is sometimes generated due to the sudden slippage.
As means for preventing the stick-slip noise, means for increasing a frictional resistance on contact surfaces of the crimped portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123 has been taken so as not to cause the sudden slippage (see Patent Literature 1, for example). In Patent Literature 1, there are disclosed, as the means for increasing the frictional resistance, a structure in which radial, oval, or cross-hatched projecting and depressed portions are formed on the contact surface of the shoulder portion 128 of the outer joint member 123 and a structure in which a spacer made of rubber or resin is provided on the contact surface of the shoulder portion 128 of the outer joint member 123.
Further, as another means for preventing the stick-slip noise, means for reducing the frictional resistance on the contact surfaces of the crimped portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123 has been taken so as not to cause the sudden slippage (see Patent Literature 2, for example). In Patent Literature 2, there is disclosed a structure in which a depressed groove is formed on the contact surface of the crimped portion 114 of the hub wheel 101 and the depressed groove is filled with grease.
Incidentally, in the related-art bearing devices for a wheel as disclosed in Patent Literatures 1 and 2, the frictional resistance on the contact surfaces of the crimped portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123 is increased or, conversely, the frictional resistance on the contact surfaces of the crimped portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123 is reduced to prevent the occurrence of sudden relative slippage, to thereby prevent the stick-slip noise.
However, as the means for increasing the frictional resistance, the projecting and depressed portions need to be formed on the contact surface of the shoulder portion 128 of the outer joint member 123 or the spacer needs to be provided. Further, as the means for reducing the frictional resistance, the depressed groove needs to be formed on the contact surface of the crimped portion 114 of the hub wheel 101. As described above, the formation of the projecting and depressed portions or the formation of the depressed groove is required, or the spacer as an independent member is required as a process of changing the frictional resistance on the contact surface. Therefore, there is a problem in that cost rises of the bearing device for a wheel are caused.
Therefore, the present invention has been proposed in view of the problem described above, and has an object to provide a bearing device for a wheel, capable of preventing stick-slip noise by simple means without requiring a process of changing a frictional resistance on a contact surface.
As a technical measure to achieve the above-mentioned object, according to one embodiment of the present invention, there is provided a bearing device for a wheel, comprising a wheel bearing, the wheel bearing comprising: an outer member having double-row outer raceway surfaces formed on an inner periphery thereof; an inner member comprising a hub wheel and an inner ring and having double-row inner raceway surfaces formed on an outer periphery thereof, which are opposed to the double-row outer raceway surfaces; and double-row balls interposed between the double-row outer raceway surfaces of the outer member and the double-row inner raceway surfaces of the inner member, the wheel bearing having a constant velocity universal joint coupled thereto through a screw fastening structure by fitting a stem section of an outer joint member of the constant velocity universal joint into an inner diameter of the hub wheel so that a shoulder portion of the outer joint member is brought into abutment against an end portion of the inner member, wherein: a plurality of projecting portions formed on one of the hub wheel and the stem section of the outer joint member to extend in an axial direction are press-fitted into another of the hub wheel and the stem section of the outer joint member, which comprises a plurality of depressed portions formed to have an interference with respect to the plurality of projecting portions, and a shape of the plurality of projecting portions is transferred to the another of the hub wheel and the stem section of the outer joint member, to thereby provide a projection and depression fitting structure in which the plurality of projecting portions and the plurality of depressed portions are brought into close contact with each other at an entire fitting contact portion therebetween; and a difference between an axial force generated by screw fastening and an axial force generated by a press-fitting force is set to 32 kN or smaller.
In the present invention, the plurality of projecting portions extending in the axial direction are formed on one of the hub wheel and the stem section of the outer joint member, and the depressed portions having the interference with respect to the projecting portions are formed in advance on another of the hub wheel and the stem section of the outer joint member. One of the hub wheel and the stem section of the outer joint member is press-fitted into the other, to thereby provide the projection and depression fitting structure in which the projecting portions and the depressed portions are brought into close contact with each other at the entire fitting contact portion therebetween.
In this case, a depressed-portion forming surface is extremely slightly cut by the projecting portions, and the shape of the projecting portions is transferred to the depressed-portion forming surface on a mating side while concomitantly involving extremely small plastic deformation or elastic deformation of the depressed-portion forming surface by the projecting portions. At this time, the projecting portions dig into the depressed-portion forming surface on the mating side so that the inner diameter of the hub wheel is slightly increased. Thus, relative movement of the projecting portions in the axial direction is allowed in this state. When the relative movement of the projecting portions in the axial direction is stopped, the inner diameter of the hub wheel is reduced to recover the original diameter. Thus, the projecting portions and the depressed portions are brought into close contact with each other at the entire fitting contact portion therebetween, with the result that the outer joint member and the hub wheel can firmly be coupled to and integrated with each other.
In this case, the depressed portions having the interference with respect to the projecting portions are formed in advance. Therefore, the outer joint member can be press-fitted into the hub wheel with a force equal to or smaller than the axial force generated by screw fastening. As a result, there is no need to separately prepare a dedicated jig when press-fitting the stem section of the outer joint member into the hub wheel. The constant velocity universal joint can easily be coupled to the wheel bearing by the screw fastening using a component of the bearing device for a wheel.
In the present invention, the difference between the axial force generated by the screw fastening and the axial force generated by the press-fitting force is set to 32 kN or smaller. By setting the difference between the axial force generated by the screw fastening and the axial force generated by the press-fitting force to 32 kN or smaller as described above, the difference between the axial force generated by the screw fastening and the axial force generated by the press-fitting force, that is, the axial force generated on contact surfaces of the end portion of the inner member and the shoulder portion of the outer joint member is set to 32 kN or smaller. As a result, a surface pressure on the contact surfaces of the end portion of the inner member and the shoulder portion of the outer joint member can be reduced. Thus, when a rotational torque is applied from the constant velocity universal joint to the wheel bearing at the start of the vehicle, the occurrence of sudden slippage on the contact surfaces can be avoided, and hence the generation of stick-slip noise can be prevented.
The screw fastening structure of the present invention may be a structure comprising: a female thread portion formed at an axial end of the stem section of the outer joint member; and a male thread portion to be locked at the hub wheel in a state of being threadedly engaged with the female thread portion. In this structure, the male thread portion is threadedly engaged with the female thread portion of the stem section, and is therefore fastened in a state of being locked at the hub wheel, to thereby fix the constant velocity universal joint to the hub wheel.
In the present invention, it is desired that the plurality of projecting portions be provided on the stem section of the outer joint member, and the plurality of depressed portions be provided on the hub wheel. Through the adoption of such a structure, the projection and depression fitting structure in which the projecting portions and the depressed portions are brought into close contact with each other at the entire fitting contact portion therebetween can easily be provided through press fitting of the stem section of the outer joint member into the hub wheel.
In the present invention, in the structure in which the plurality of projecting portions are provided on the stem section of the outer joint member and the plurality of depressed portions are provided on the hub wheel, it is desired that a value obtained by dividing an axial length from the shoulder portion of the outer joint member, against which the end portion of the inner member abuts, to the plurality of projecting portions by a maximum outer diameter of the stem section be set to 0.3 or smaller, and that a value obtained by dividing an axial length of the stem section by the maximum outer diameter of the stem section be set to 1.3 or smaller. By setting the axial length with respect to the maximum outer diameter of the stem section as described above, when the rotational torque is applied from the constant velocity universal joint to the wheel bearing at the start of the vehicle, a torsion amount of the outer joint member can be reduced while ensuring an effective fitting length in the projection and depression fitting structure. As a result, the occurrence of the sudden slippage on the contact surfaces of the end portion of the inner member and the shoulder portion of the outer joint member can be reliably avoided, and hence the generation of the stick-slip noise can be prevented.
Further, when the bearing device for a wheel has a configuration in which the hub wheel and the outer joint member of the constant velocity universal joint are fastened through an intermediation of a bolt, it is desired that rotation of the bolt in a loosening direction be regulated between a head portion of the bolt and the hub wheel. In this manner, a fastened state of the hub wheel and the constant velocity universal joint can be maintained over a long period of time. Thus, inconvenience such as generation of abnormal noise and acceleration of wear due to loosening of the fastened bolt can be suppressed.
In order to regulate the rotation of the bolt in the loosening direction, the hub wheel may comprise an engagement portion, and the head portion of the bolt may comprise a loosening prevention member engageable with the engagement portion mounted thereon.
Further, the engagement portion may comprise a protruding portion or a recessed portion, and the loosening prevention member may be configured to be engageable with the engagement portion by being crimped at a position of the engagement portion or in a vicinity thereof.
Alternatively, the engagement portion may comprise a protruding portion or a recessed portion, and the loosening prevention member may comprise a projecting portion or a depressed portion engageable with the engagement portion.
Further, the loosening prevention member may comprise a cap member mountable onto the head portion of the bolt through press fitting.
Further, the loosening prevention member may comprise a clip member having an opening portion in a part in a peripheral direction. The clip member is mountable onto the head portion of the bolt through elastic deformation of the opening portion in an enlarged manner.
Further, in order to regulate the rotation of the bolt in the loosening direction, the hub wheel may comprise an engagement portion, and the head portion of the bolt may comprise a flange portion engageable with the engagement portion.
Further, the engagement portion may comprise a protruding portion or a recessed portion, and the flange portion may be configured to be engageable with the engagement portion by being crimped at a position of the engagement portion or in a vicinity thereof.
Further, in order to regulate the rotation of the bolt in the loosening direction, the head portion of the bolt may be fixed to the hub wheel by welding.
According to the present invention, the plurality of projecting portions formed on one of the hub wheel and the stem section of the outer joint member to extend in the axial direction are press-fitted into the other having the plurality of depressed portions formed to have the interference with respect to the projecting portions. The shape of the projecting portions is transferred to the other to provide the projection and depression fitting structure in which the projecting portion and the depressed portions are brought into close contact with each other at the entire fitting contact portion therebetween. As a result, the depressed portions having the interference with respect to the projecting portions are formed in advance. Therefore, the outer joint member can be press-fitted into the hub wheel with the force equal to or smaller than the axial force generated by the screw fastening. As a result, by setting the difference between the axial force generated by the screw fastening and the axial force generated by the press-fitting force to 32 kN or smaller, the surface pressure on the contact surfaces of the end portion of the inner member and the shoulder portion of the outer joint member can be reduced. Thus, when the rotational torque is applied from the constant velocity universal joint to the wheel bearing at the start of the vehicle, the occurrence of sudden slippage on the contact surfaces can be avoided. Thus, the generation of stick-slip noise can be prevented.
Now, a bearing device for a wheel according to embodiments of the present invention is described in detail. A bearing device for a wheel illustrated in
The hub wheel 1 has an inner raceway surface 8 on the outboard side formed on an outer peripheral surface thereof, and comprises a wheel mounting flange 9 for allowing a wheel (not shown) to be mounted thereto. Hub bolts 10 for fixing a wheel disc are equiangularly embedded in the wheel mounting flange 9. The inner ring 2 is fitted to a small-diameter step portion 11 formed on an outer peripheral surface of the hub wheel 1 on the inboard side, and an inner raceway surface 12 on the inboard side is formed on an outer peripheral surface of the inner ring 2.
The inner ring 2 is press-fitted with adequate interference for the purpose of preventing creep. The inner raceway surface 8 on the outboard side that is formed on the outer peripheral surface of the hub wheel 1 and the inner raceway surface 12 on the inboard side that is formed on the outer peripheral surface of the inner ring 2 constitute double-row raceway surfaces. The inner ring 2 is press-fitted into the small-diameter step portion 11 of the hub wheel 1, and the end portion of the small-diameter step portion 11 is crimped outward by orbital forming. As a result, the inner ring 2 is retained by a crimped portion 13 thus formed and integrated with the hub wheel 1, to thereby apply preload to the wheel bearing 6.
The outer ring 5 has double-row outer raceway surfaces 14 and 15 formed on an inner peripheral surface thereof, which are respectively opposed to the inner raceway surface 8 formed on the hub wheel 1 and the inner raceway surface 12 formed on the inner ring 2. The outer ring 5 has a vehicle body mounting flange 16 for mounting the wheel bearing 6 to a vehicle body (not shown) on an outer peripheral surface thereof. The vehicle body mounting flange 16 is fixed to a knuckle extending from a suspension device (not shown) of the vehicle body with a bolt or the like by using a mounting hole 17.
The wheel bearing 6 has a double-row angular ball bearing structure. That is, the balls 3 and 4 are interposed between the inner raceway surfaces 8 and 12 formed on the outer peripheral surfaces of the hub wheel 1 and the inner ring 2 and the outer raceway surfaces 14 and 15 formed on the inner peripheral surface of the outer ring 5. Thus, the balls 3 and 4 in respective rows are equiangularly supported by cages 18 and 19. Note that, the wheel bearing 6 has a structure integrated with the hub wheel 1 by retaining the inner ring 2 by the crimped portion 13 and therefore, is separable from an outer joint member 20 of the constant velocity universal joint 7.
At opening portions on both ends of the wheel bearing 6, a pair of seals 21 and 22 for sealing annular spaces between the outer ring 5 and the hub wheel 1 and between the outer ring 5 and the inner ring 2 are provided. The seals 21 and 22 are fitted to the inner diameter at both end portions of the outer ring 5 so as to prevent leakage of a lubricant such as grease filled inside and entrance of water and foreign matter from the outside. The seal 21 comprises a cored bar and an elastic member. A distal end of a lip of the elastic member is held in sliding-contact with the outer peripheral surface of the hub wheel 1. The type of the seal 22 is called “pack seal”. Specifically, the seal 22 comprises two L-shaped cored bars and an elastic member. The elastic member is mounted to one of the cored bars, whereas the distal end of the lip of the elastic member is held in sliding-contact with an outer peripheral surface of another of the cored bars, which is mounted to an outer periphery of the inner ring.
The constant velocity universal joint 7 is a fixed type constant velocity universal joint that is provided to one end of a shaft 23 constituting a drive shaft and allows only an angular displacement between two shafts on a driving side and a driven side. The constant velocity universal joint 7 comprises the outer joint member 20 having track grooves 24 formed in an inner peripheral surface thereof, an inner joint member 26 having track grooves 25 formed in an outer peripheral surface thereof so as to be opposed to the track grooves 24 of the outer joint member 20, balls 27 built into spaces between the track grooves 24 of the outer joint member 20 and the track grooves 25 of the inner joint member 26, and a cage 28 interposed between the inner peripheral surface of the outer joint member 20 and the outer peripheral surface of the inner joint member 26 to retain the balls 27.
The outer joint member 20 comprises a cup-shaped mouth section 29 that accommodates internal components such as the inner joint member 26, the balls 27, and the cage 28, and a stem section 30 that integrally extends from the mouth section 29 in an axial direction. An axial end of the shaft 23 is press-fitted into the inner joint member 26, and is coupled to the shaft 23 by spline fitting to allow torque transmission therebetween.
A bellows-like boot 31 made of a resin is mounted between the outer joint member 20 of the constant velocity universal joint 7 and the shaft 23 to prevent leakage of a lubricant such as grease filled inside the joint, and to prevent entrance of foreign matter from outside the joint, thereby attaining a structure of closing an opening portion of the outer joint member 20 with the boot 31. The boot 31 comprises a large-diameter end portion fastened and fixed with a boot band on an outer peripheral surface of the outer joint member 20, a small-diameter end portion fastened and fixed with a boot band on an outer peripheral surface of the shaft 23, and a flexible bellows portion connecting the large-diameter end portion and the small-diameter end portion, and reduced in diameter as approaching from the large-diameter end portion toward the small-diameter end portion.
In the bearing device for a wheel, as illustrated in
In the bearing device for a wheel, as illustrated in
In this manner, a projection and depression fitting structure M, in which the projecting portions 33 and the depressed portions 37 are brought into close contact with each other at an entire fitting contact portion X therebetween, is formed. As a result, the outer joint member 20 and the hub wheel 1 can firmly be coupled to and integrated with each other. Through the coupling thus carried out at low cost with high reliability, any gap that may cause a backlash is not formed in the radial direction and a peripheral direction in the fitting portion between the stem section 30 and the hub wheel 1 in the projection and depression fitting structure M, and hence the entire fitting contact portion X contributes to torque transmission so that stable torque transmission can be carried out. As a result, annoying gear rattling noise can be prevented over a long period of time. The close contact is realized at the entire fitting contact portion X, and hence the strength of the torque transmitting portion is enhanced. As a result, the bearing device for a wheel is light-weighted and downsized.
Here, a surface hardness of the projecting portions 33 is set larger than a surface hardness of the depressed portions 36. In this case, the difference between the surface hardness of the projecting portions 33 and the surface hardness of the depressed portions 36 is set equal to or larger than 20 in HRC. Thus, when the stem section 30 of the outer joint member 20 is press-fitted into the shaft hole 34 of the hub wheel 1, the depressed-portion forming surface is extremely slightly cut by the peripheral side wall portions 71 of the projecting portions 33. While concomitantly involving the extremely small plastic deformation or elastic deformation of the depressed-portion forming surface by the peripheral side wall portions 71 of the projecting portions 33, the shape of the peripheral side wall portions 71 of the projecting portions 33 can be easily transferred to the depressed-portion forming surface on the mating side.
Further, as illustrated in
Further, an accommodating portion 40 for accommodating a flash portion 39 generated due to the transfer of the shape of the projecting portions through the press fitting (cutting work and plastic deformation or elastic deformation occurring therewith) is secured between the shaft hole 34 of the hub wheel 1 and the stem section 30 of the outer joint member 20 (see
The bearing device for a wheel comprises the following screw fastening structure N, as illustrated in
When the shape of the peripheral side wall portions 71 of the projecting portions 33 is transferred to the shaft hole 34 of the hub wheel 1 to form the depressed portions 37 at the time of press fitting the stem section 30 into the hub wheel 1, the depressed portions 36 having the interference n with respect only to the peripheral side wall portions 71 of the projecting portions 33, that is, the depressed portions 36 set smaller in the peripheral dimension than the projecting portions 33 are formed in advance (see
As described above, there is no need to separately prepare a dedicated jig when press-fitting the outer joint member 20 into the hub wheel 1 of the wheel bearing 6. The constant velocity universal joint 7 can easily be coupled to the wheel bearing 6 with the bolt 42 that is a component of the bearing device for a wheel. Further, the outer joint member 20 can be press-fitted by applying the relatively small pull-in force, which is equal to or smaller than the axial force generated by fastening the bolt 42, and hence the workability can be enhanced when pulling in the outer joint member 20 with the bolt 42. Still further, there is no need to apply a significant press-fitting load, and hence the damage to (collapse of) the projections and depressions can be prevented in the projection and depression fitting structure M, with the result that a high-quality and long-life projection and depression fitting structure M can be realized.
The screw fastening structure N, in which the shoulder portion 45 of the outer joint member 20 is brought into abutment against the crimped portion 13 of the hub wheel 1 by fastening the bolt 42 as described above, is formed. In the bearing device for a wheel, the outer joint member 20 can be press-fitted into the hub wheel 1 with a force that is equal to or smaller than the axial force generated by fastening the bolt 42. Therefore, a difference between the axial force generated by fastening the bolt 42 and an axial force generated by a press-fitting force on the outer joint member 20 into the hub wheel 1 is set to 32 kN or smaller, preferably, 28 kN or smaller. This means that the difference between the axial force generated by fastening the bolt 42 and the axial force generated by the press-fitting force on the stem section 30 into the hub wheel 1, that is, an axial force generated on contact surfaces of the crimped portion 13 of the hub wheel 1 and the shoulder portion 45 of the outer joint member 20 is set to 32 kN or smaller.
Here, the related-art bearing device for a wheel (see
On the other hand, the bearing device for a wheel of this embodiment adopts the structure in which the depressed-portion forming surface is extremely slightly cut by the peripheral side wall portions 71 of the projecting portions 33 in a state in which the depressed portions 36 having the interference n with respect to the peripheral side wall portions 71 of the projecting portions 33 formed on the stem section 30 of the outer joint member 20 are formed on the shaft hole 34 of the hub wheel 1 in advance at the time of fastening the bolt 42, and the stem section 30 of the outer joint member 20 is press-fitted into the shaft hole 34 of the hub wheel 1, while concomitantly involving the extremely small plastic deformation or elastic deformation of the depressed-portion forming surface, which is caused by the peripheral side wall portions 71 of the projecting portions 33, so that the depressed portions 37 are formed by transferring the shape of the peripheral side wall portions 71 of the projecting portions 33 onto the depressed-portion forming surface (see
Specifically, the axial force generated on the contact surfaces of the crimped portion 13 of the hub wheel 1 and the shoulder portion 45 of the outer joint member 20 can be made smaller than the axial force generated by fastening the bolt 42 by the amount of axial force generated by the press-fitting force on the outer joint member 20 into the hub wheel 1. In this manner, a surface pressure on the contact surfaces of the crimped portion 13 of the hub wheel 1 and the shoulder portion 45 of the outer joint member 20 can be made smaller than in the case of the related-art bearing device for a wheel. Thus, when the rotational torque is applied from the constant velocity universal joint 7 to the wheel bearing 6 at the start of the vehicle, the occurrence of sudden slippage on the contact surface can be avoided. Therefore, the generation of the stick-slip noise can be prevented.
In
Note that, as illustrated in
In the experiments based on the axial-force measurements, as shown in
Further, in the bearing device for a wheel according to this embodiment, as illustrated in
As described above, by setting the axial lengths L1 and L2 with respect to the maximum outer diameter D of the stem section 30, when the rotational torque is applied from the constant velocity universal joint 7 to the wheel bearing 6 at the start of the vehicle, the torsion amount of the outer joint member 20 can be reduced after the effective fitting length in the projection and depression fitting structure M is ensured. As a result, the occurrence of the sudden slippage on the contact surfaces of the crimped portion 13 of the hub wheel 1 and the shoulder portion 45 of the outer joint member 20 can be reliably avoided. Therefore, the generation of the stick-slip noise can be further reliably prevented.
Note that, if the value obtained by dividing the axial length L1 from the shoulder portion 45 of the outer joint member 20 to the projecting portions 33 by the maximum outer diameter D of the stem section 30 is larger than 0.3 or the value obtained by dividing the axial length L2 of the stem section 30 by the maximum outer diameter D of the stem section 30 is larger than 1.3, it becomes difficult to ensure the effective fitting length in the projection and depression fitting structure M or reduce the torsion amount of the outer joint member 20 at the time of application of the torque. As a result, the sudden slippage is likely to occur on the contact surfaces of the crimped portion 13 of the hub wheel 1 and the shoulder portion 45 of the outer joint member 20, and hence it becomes difficult to prevent the generation of the stick-slip noise.
In the embodiment described above, the case where the interference n is set to be provided with respect only to the peripheral side wall portions 71 (see
Also in the embodiment described above, as illustrated in
Note that, in the embodiment illustrated in
Each of bearing devices for a wheel according to embodiments illustrated in
In the embodiment illustrated in
In the embodiment illustrated in
In the embodiment illustrated in
In the embodiment illustrated in
In the embodiment illustrated in
In the embodiment illustrated in
In the embodiment illustrated in
In the embodiments described above, the screw fastening structure N, in which the bolt 42 is fastened in a state of being locked to the protruding wall portion 43 of the hub wheel 1 by threadedly engaging the bolt 42 with the female thread portion 41 of the stem section 30, has been exemplarily described. However, another screw fastening structure may also be configured to comprise a male thread portion formed at the axial end of the stem section 30 of the outer joint member 20 and a nut that is a female thread portion to be locked to the protruding wall portion 43 of the hub wheel 1 in a state of being threadedly engaged with the male thread portion.
Further, in the embodiments described above, the crimping structure, in which an end portion of the small-diameter step portion 11 of the hub wheel 1 is crimped outward by orbital forming to retain the inner ring 2 by the crimped portion 13 to be integrated with the hub wheel 1 so that the constant velocity universal joint 7 is separable from the wheel bearing 6, has been exemplarily described. However, anon-crimping structure, in which the inner ring 2 is press-fitted into the small-diameter step portion 11 of the hub wheel 1 so that the end portion of the inner ring 2 is brought into abutment against the shoulder portion 45 of the outer joint member 20, may also be used.
Further, in the embodiments described above, the application to the bearing device for a wheel of a type in which one of the double-row inner raceway surfaces 8 and 12 formed on the inner member comprising the hub wheel 1 and the inner ring 2, that is, the inner raceway surface 8 on the outboard side, is formed on the outer periphery of the hub wheel 1 (referred to as “third generation”), has been exemplarily described. However, the application is also possible to the bearing device for a wheel of a type in which a pair of inner rings is press-fitted over the outer periphery of the hub wheel 1 so that the raceway surface 8 on the outboard side is formed on the outer periphery of one of the inner rings and the raceway surface 12 on the inboard side is formed on the outer periphery of another of the inner rings (referred to as “first generation” or “second generation”).
Incidentally, the configuration in which the hub wheel and the constant velocity universal joint are fastened by the bolt, as described in the above-mentioned embodiments, is capable of assembling and disassembling and therefore is excellent in maintainability. If the fastened bolt is loosened after the incorporation into the vehicle, however, there is a fear of inconvenience such as generation of a backlash to generate abnormal noise or acceleration of wear.
Therefore, a configuration of the bearing device for a wheel, which is capable of preventing the bolt from being loosened over a long period of time, is proposed below. Note that, in the drawings for illustrating each of embodiments described below, for constituent elements such as members or components having the same functions or shape, the repeated description thereof is omitted by providing the same reference symbols as long as distinction is possible.
As illustrated in
Specifically, as illustrated in
Here, the number of provided depressed portions 82b is twice (twelve in total) as many as the number (six in
Further, an inner diameter of the side wall portion 82a of the cap main body 82 is set slightly smaller than an outer diameter of a corresponding portion of the head portion 42a. Specifically, the cap member 80 is fitted by press-fitting over the head portion 42a. Therefore, the cap member 80 hardly comes off in the axial direction.
An engagement portion 81 that is engageable with the cap member 80 is provided to the hub wheel 1 on a side where the cap member 80 is provided. The engagement portion 81 is a protruding portion 84 partially projecting in the peripheral direction.
As illustrated in
Note that, in this embodiment, only one protruding portion 84 is provided. However, a plurality of the protruding portions 84 may be provided in the peripheral direction so that the flange portion 83 is crimped to each of the protruding portions 84 or an arbitrarily selected one of the protruding portions 84.
As illustrated in
As illustrated in
Note that, also in this embodiment, a plurality of the recessed portions 85 may be provided over the peripheral direction so that the flange portion 83 is crimped to each of the recessed portions 85 or an arbitrarily selected one of the recessed portions 85.
As illustrated in
In a center of the clip main body 86a, an insertion hole 86e, into which the head portion 42a of the bolt 42 is inserted, is formed. In this case, the insertion hole 86e is formed to have a hexagonal shape that is the same as the shape of the head portion 42a of the bolt 42. By achieving a state in which the head portion 42a is inserted into the insertion hole 86e, rotation of the clip member 86 in the peripheral direction with respect to the head portion 42a is regulated. Further, an inner diameter of the insertion hole 86e is set slightly smaller than an outer diameter of a corresponding portion of the head portion 42a. In this manner, the clip member 86 mounted to the head portion 42a hardly comes off in the axial direction. Further, in both end portions of the clip main body 86a, which form the opening portion 86c, hole portions 86d to be gripped by a tool such as pliers when the clip member 86 is mounted onto the head portion 42a of the bolt 42 are formed.
On the other hand, on a side of the hub wheel 1, on which the clip member 86 is provided, the recessed portions 85 are provided as the engagement portion 81 to which the projecting portions 87 of the clip member 86 are engageable. A plurality of the recessed portions 85 are provided in the peripheral direction.
When the clip member 86 is mounted onto the head portion 42a of the bolt 42, both end portions of the clip main body 86a are gripped by the pliers or the like. Then, the clip main body 86a is elastically deformed so that the opening portion 86c is enlarged and the head portion 42a of the bolt 42 is inserted into the insertion hole 86e of the clip main body 86a in this state. Then, by an elastic restoring force of the clip member 86, the clip main body 86a is locked to the side surface of the head portion 42a.
Further, at this time, one of the plurality of projecting portions 87 of the clip member 86 is positionally aligned with an arbitrarily selected one of the recessed portions 85 and is then inserted into the corresponding recessed portion 85. In this manner, the projecting portion 87 is brought into a state of being engageable with the recessed portion 85 in the peripheral direction. Therefore, the bolt 42 can be held in the peripheral direction with respect to the hub wheel 1 through an intermediation of the clip member 86. As described above, in this embodiment, the rotation of the bolt 42 in the loosening direction is regulated.
Further, as illustrated in
As illustrated in
In this case, when the cap member 80 is press-fitted over the head portion 42a of the bolt 42, one of the plurality of projecting portions 87 is positionally aligned with an arbitrarily selected one of the recessed portions 85 and is then inserted into the corresponding recessed portion 85 in the same manner as described above. As a result, the projecting portion 87 is brought into a state of being engageable with the recessed portion 85 in the peripheral direction, thereby holding the bolt 42 to the hub wheel 1 through an intermediation of the cap member 80 in the peripheral direction. In this manner, in this embodiment, the rotation of the bolt 42 in the loosening direction is regulated.
In the fifth embodiment illustrated in
In this case, the clip main body 86a is elastically deformed to mount the clip member 86 over the head portion 42a of the bolt 42 as in the case described above. At this time, the depressed portion 88 of the clip member 86 is positionally aligned with the protruding portion 84 of the hub wheel 1. As a result, the depressed portion 88 is brought into a state of being engageable with the protruding portion 84 in the peripheral direction. In this manner, the rotation of the bolt 42 in the loosening direction is regulated through an intermediation of the clip member 86.
In the sixth embodiment illustrated in
In this case, when the cap member 80 is press-fitted over the head portion 42a of the bolt 42 to be fitted thereto, the depressed portion 88 of the cap member 80 is positionally aligned with the protruding portion 84 of the hub wheel 1. In this manner, the depressed portion 88 is brought into a state of being engageable with the protruding portion 84 in the peripheral direction. In this manner, the rotation of the bolt 42 in the loosening direction is regulated through an intermediation of the cap member 80.
In the seventh embodiment illustrated in
Although the bolt 42 is configured to be prevented from being loosened by using the loosening prevention member 79 (cap member 80 or clip member 86) in each of the embodiments described above, the loosening prevention member 79 as described above is not used in the eighth embodiment illustrated in
First, the bolt 42 is screwed into the female thread portion 41 (see
Note that, the flange portion 42d is preferred not to be subjected to thermosetting treatment so as to facilitate the crimping. Further, a plurality of the protruding portions 84 may be provided in the peripheral direction so that the flange portion 42d is crimped to each of the protruding portions 84 or an arbitrarily selected one of the protruding portions 84.
In the ninth embodiment illustrated in
Also in this case, the bolt 42 is screwed into the female thread portion 41 (see
Note that, in the same manner as described above, the flange portion 42d is preferred not to be subjected to thermosetting treatment so as to facilitate the crimping. Further, a plurality of the recessed portions 85 may be provided over the peripheral direction so that the flange portion 42d is crimped to each of the recessed portions 85 or an arbitrarily selected one of the recessed portions 85.
In the tenth embodiment illustrated in
In the eleventh embodiment, a pin-like member 89 is used as the loosening prevention member 79. The pin-like member 89 comprises a shaft-like insertion portion 91 that is insertable into an insertion hole 90 provided in the hub wheel 1, and a deformable portion 92 formed integrally therewith. Further, the insertion hole 90 is formed on a radial surface of the hub wheel 1, against which the head portion 42a of the bolt 42 abuts.
As illustrated in
Although the crimped deformable portion 92 is brought into close contact with the angular portion 42c of the head portion 42a of the bolt 42 in
In examples illustrated in
In this case, after a distal end of the pin-like member 89 is inserted into the insertion hole 90 as illustrated in
Further, also in this case, a portion, with which the pin-like member 89 is brought into close contact, may be the angular portion 42c formed on the side surface of the head portion 42a as illustrated in
In the twelfth embodiment, a washer 93 is interposed between the hub wheel 1 and the head portion 42a of the bolt 42. The above-mentioned insertion hole 90 is formed through the washer 93. Otherwise, the twelfth embodiment is basically the same as the embodiments illustrated in
In this case, after the bolt 42 and the hub wheel 1 are fastened through the washer 93 interposed therebetween, the distal end of the insertion portion 91 of the pin-like member 89 is inserted into the insertion hole 90 (see
Further, also in this case, a portion of the bolt 42, with which the pin-like member 89 is brought into close contact, may be the angular portion 42c formed on the side surface of the head portion 42a (see
Further, as in examples illustrated in
Further, also in this case, a portion of the bolt 42, with which the pin-like member 89 is brought into close contact, may be the angular portion 42c formed on the side surface of the head portion 42a (see
Each of the embodiments of the bolt loosening prevention structure has been described above. According to the bolt loosening prevention structure of each of the embodiments, the rotation of the bolt in the loosening direction with respect to the hub wheel can be regulated between the head portion of the bolt and the hub wheel. In this manner, the fastened state of the hub wheel and the constant velocity universal joint can be maintained over a long period of time. As a result, inconvenience such as the generation of abnormal noise or the acceleration of wear due to the loosening of the fastened bolt can be suppressed.
Further, the bolt loosening is prevented by the head portion of the bolt, which is exposed from the hub wheel. Therefore, whether or not the loosening is prevented after the bolt is fastened can be easily confirmed visually from the outside.
Further, the application of the bolt loosening prevention structure according to each of the embodiments described above is not limited to the above-mentioned bearing device for a wheel. For example, the above-mentioned bolt loosening prevention structure is also applicable to bearing devices for a wheel illustrated in
Specifically, the bearing device for a wheel illustrated in
The inner member 200 comprises a hub wheel 201 having a wheel mounting flange 209 for allowing a wheel (not shown) to be mounted thereto and an inner ring 202 mounted on an outer peripheral surface of the hub wheel 201. On outer peripheral surfaces of the hub wheel 201 and the inner ring 202, inner raceway surfaces 207 and 208 are respectively formed. On the other hand, the outer member 205 has an inner peripheral surface on which double-row outer raceway surfaces 213 and 214 respectively opposed to the inner raceway surfaces 207 and 208 of the hub wheel 201 and the inner ring 202 are formed. The double-row balls 203 and 204 are interposed between the outer raceway surfaces 213 and 214 and the inner raceway surfaces 207 and 208, which are opposed to each other.
The constant velocity universal joint 206 comprises an outer joint member 224 having track grooves 223 formed in an inner peripheral surface thereof, an inner joint member 226 having track grooves 225 formed in an outer peripheral surface thereof so as to be opposed to the track grooves 223 of the outer joint member 224, balls 227 built into spaces between the track grooves 223 and 225, a cage 228 interposed between the inner peripheral surface of the outer joint member 224 and the outer peripheral surface of the inner joint member 226 to retain the balls 227, and the like.
The outer joint member 224 comprises a mouth section 229 that accommodates internal components such as the inner joint member 226, the balls 227, and the cage 228, and a stem section 230 that integrally extends from the mouth section 229 in an axial direction. Further, a male spline 237 including a plurality of projecting portions extending in the axial direction is formed on an outer peripheral surface of the stem section 230.
Correspondingly, on an inner peripheral surface of a hole portion 238 of the hub wheel 201, a female spline 239 to be fitted to the male spine 237 of the stem section 230 is formed. By the engagement of both the splines in a state in which the stem section 230 is inserted into the hole portion 238, the hub wheel 201 and the outer joint member 224 are coupled to each other to allow torque transmission therebetween.
Further, a screw hole 240 is formed in the stem section 230. A bolt 250 is inserted into the screw hole 240 so that the bolt 250 is threadedly engaged with a female thread portion 241 formed on the screw hole 240, and a head portion 250a of the bolt 250 is brought into abutment against a radial end surface 210 of the hub wheel 201, thereby fastening the constant velocity universal joint 206 to the hub wheel 201.
Further, similarly to the bearing device for a wheel illustrated in
In this embodiment, an axial-alignment protruding portion 231 having a disc-like shape is provided integrally with the mouth section 229 of the constant velocity universal joint 206. By fitting the axial-alignment protruding portion 231 into the hole portion 238 of the hub wheel 201, the hub wheel 201 and the constant velocity universal joint 206 are coupled to each other while being axially aligned. Further, in the bearing device for a wheel, face splines 242 and 243 are formed on surfaces of the mouth section 229 of the outer joint member 224 and the hub wheel 201, which are opposed to each other, and are engaged with each other. Each of the face splines 242 and 243 comprises a plurality of projecting portions and depressed portions extending in the radial direction, which are formed alternately along the peripheral direction. By the engagement of the face splines 242 and 243, misalignment between the hub wheel 201 and the fixed type constant velocity universal joint 206 in the peripheral direction is eliminated.
Further, similarly to the bearing device for a wheel illustrated in
In contrast to the bearing device for a wheel illustrated in
As described above, also in the bearing devices for a wheel illustrated in
Note that, the present invention is not limited to the embodiments described above, and as a matter of course, may be carried out in various other embodiments without departing from the gist of the present invention. The scope of the present invention is defined in the scope of claims, and encompasses meaning of equivalents described in the scope of claims and all modifications in the scope of claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-049196 | Mar 2013 | JP | national |
| 2013-058233 | Mar 2013 | JP | national |
| 2013-114139 | May 2013 | JP | national |
| 2013-147637 | Jul 2013 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2014/053404 | 2/14/2014 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2014/141808 | 9/18/2014 | WO | A |
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| 20160016431 A1 | Jan 2016 | US |
