JP2010069926A - Hub unit for supporting drive wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hub unit for supporting a drive wheel, capable of attaining high installability and high rigidity by devising its shape. <P>SOLUTION: A female spline 23 of a hub ring 12 is divided into a first female spline 40 nearer to an outer end in the axial direction and a second female spline 41 nearer to an inner end in the axial direction. The first female spline 40 is formed to be fitted onto a female spline 33 of a spline shaft 32 and the second female spline 41 is formed into a taper shape so that clearances between the spline shaft 32 and the female spline 33 in the diametrical and peripheral directions gradually increase from a boundary position B to the first female spline 40 toward an inner end position C in the axial direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention supports the driving wheels of an automobile (front wheels of FF vehicles, rear wheels of FR vehicles and RR vehicles, all wheels of 4WD vehicles) rotatably with respect to a suspension system, and rotationally drives the driving wheels. The present invention relates to a hub unit for driving wheel support used in the above.

  For example, as a driving wheel support hub unit for supporting a driving wheel of an automobile with respect to a suspension device, one as shown in FIG. 14 is known (for example, see Patent Document 1). This drive wheel support hub unit 100 supports a hub 105 having a hub ring 102 and a pair of inner rings 103, 104 on the inner diameter side of an outer ring member 101, via a plurality of rolling elements 106, 106, so as to be rotatable. Yes.

When the driving wheel support hub unit 100 is assembled to an automobile, the outer ring member 101 is coupled and fixed to a knuckle 107 constituting a suspension device. Further, the disc rotor 109 and the wheel 110 of the brake device are attached to the attachment flange 108 of the hub wheel 102 by tightening bolts 111 and nuts that penetrate the attachment flange 108. Further, the male spline 123 of the spline shaft 122 fixed at the center of the outer end surface 121 of the constant velocity joint outer ring 120 is spline-engaged with the female spline 112 of the hub ring 102. At the same time, the radially outer end portion of the outer end face 121 of the constant velocity joint outer ring 120 is brought into contact with the inner end face 124 of the inner ring 104. In this state, the hub 125 and the pair of inner rings 103 and 104 are coupled to the spline shaft 122 by screwing the nut 125 to the tip of the spline shaft 122 and further tightening. Moreover, the female spline 112 and the male spline 123 are formed in a taper shape to prevent / suppress generation of abnormal noise.
Japanese Patent No. 4020045

  By the way, in the driving wheel supporting hub unit 100 described in Patent Document 1, the female spline 112 of the hub wheel 102 is formed in a tapered shape with a constant inclination angle over the entire axial direction, and the male spline on the constant velocity joint side. The spline 123 is also tapered in accordance with it. In this case, although it seems that it is excellent in terms of ease of assembly of the hub unit, since both the splines 112 and 123 are in point contact with each other in torque transmission during sudden turning and acceleration of the vehicle, stress concentration is likely to occur. There is a need to further increase the strength. Such a problem is the same when both the female spline 112 and the male spline 123 have a uniform outer diameter over the entire axial direction.

  The present invention has been made to eliminate the above-described disadvantages, and an object of the present invention is to provide a drive wheel support hub unit that can be easily assembled and improved in strength by devising the shape. is there.

The present invention is achieved by the following configurations.
(1) an outer ring member having first and second outer ring raceways on the inner peripheral surface;
A hub wheel having a flange for supporting a wheel at a portion near the outer end in the axial direction, and a female spline that can be coupled with a male spline formed on the outer peripheral surface of the drive shaft, formed on the inner peripheral surface, and the hub wheel A hub that forms first and second inner ring raceways opposed to the first and second outer ring raceways,
Between the first and second outer ring raceways and the first and second inner ring raceways, a plurality of rolling elements each provided in multiple rows,
In a drive wheel support hub unit comprising:
The female spline of the hub wheel is divided into a first female spline near the outer end in the axial direction and a second female spline near the inner end in the axial direction,
The first female spline is formed so as to fit with the male spline of the drive shaft,
In the second female spline, the radial and circumferential clearances with the male spline of the drive shaft gradually increase from the boundary position with the first female spline toward the inner end position in the axial direction. A hub unit for supporting a driving wheel, wherein the hub unit is formed in a tapered shape.
(2) The boundary position between the first and second female splines is disposed between the center positions of the double row rolling elements,
The radial length of the second female spline is the circumferential direction between the male spline of the drive shaft and the female spline of the hub wheel at the reference pitch diameter position at the axially inner end position of the second female spline. The drive wheel support hub unit according to (1), characterized in that the hub unit is smaller than the gap.
(3) The male spline of the drive shaft has a substantially constant reference pitch outer diameter over the entire axial direction.
The drive wheel support hub unit according to (1) or (2), wherein the first female spline has a reference pitch inner diameter substantially the same as a reference pitch outer diameter of the male spline.
(4) The male spline of the drive shaft is formed in a tapered shape having a predetermined inclination angle over the entire axial direction.
The first female spline is formed in a tapered shape having an inclination angle substantially equal to a predetermined inclination angle of the male spline,
The drive wheel support hub unit according to (1) or (2), wherein the second female spline is formed in a tapered shape having an inclination angle larger than an inclination angle of the first female spline. .
(5) On the inner peripheral surface of the hub wheel, a chamfered portion is formed closer to the inner end in the axial direction than the second female spline.
The axial length of the second female spline is longer than the axial length of the chamfered portion,
The radial length of the second female spline is 1/50 or less of the radial length of the chamfered portion, for supporting a driving wheel according to any one of (1) to (4) Hub unit.
The “radial length of the second female spline” in the present invention is the difference between the reference pitch inner diameters of the boundary position with the first female spline and the axially inner end position of the second female spline. Yes, “the radial length of the chamfered portion” means the difference between the inner diameters at both axial ends.

  As described above, according to the drive wheel supporting hub unit of the present invention, the female spline of the hub wheel is divided into the first female spline near the outer end in the axial direction and the second female spline near the inner end in the axial direction. The first female spline is formed to mate with the male spline of the drive shaft, and the second female spline is driven from the boundary position with the first female spline toward the axial inner end position. The shaft is formed in a tapered shape so that the radial and circumferential clearances with the male spline gradually increase. As a result, when torque is transmitted from the constant velocity joint, the male spline on the constant velocity joint side is elastically deformed and comes into contact with the female spline of the hub wheel, but the contact range becomes wide even if the torque increases. Since no force is received by only a portion as in the conventional case, the stress is not concentrated and the structure is advantageous in terms of strength.

  Hereinafter, a drive wheel support hub unit according to each embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
1 to 6 show a drive wheel support hub unit according to the first embodiment of the present invention. A driving wheel support hub unit 10 shown in FIGS. 1 and 2 rotates a hub 15 having a hub ring 12 and an inner ring 14 on the inner diameter side of an outer ring member 11 via balls 16 and 16 which are a plurality of rolling elements. Supports freely. Out of these members, the outer ring member 11 is coupled and fixed to the knuckle 107 (see FIG. 14) constituting the suspension device by a flange portion 17 provided on the outer peripheral surface of the axially intermediate portion, and does not rotate during use. . Further, first and second outer ring raceways 18 and 19 are provided on the inner peripheral surface of the outer ring member 11, and the hub 15 is rotatable on the inner diameter side of the outer ring member 11 so as to be concentric with the outer ring member 11. I support it.

  The hub wheel 12 is an outer end in the axial direction of the outer peripheral surface ("outside" with respect to the axial direction means the outer side in the width direction of the vehicle when assembled to the automobile, and is the left side of Figs. 1 and 2. The right side of FIGS. 1 and 2 which is the central side in the width direction is referred to as “inside” with respect to the axial direction. The same applies throughout the present specification and claims.) A first inner ring raceway 21 is also formed at the intermediate portion of the mounting flange 20, and a small diameter step portion 22 having an outer diameter smaller than that of the portion where the first inner ring raceway 21 is formed at the inner end portion. Are provided with a female spline 23 at the center and a chamfered portion 24 closer to the inner end in the axial direction than the female spline 23.

  A disc rotor 109 (see FIG. 14) and a wheel 110 (see FIG. 14) of a brake device are attached to the mounting flange 20 by tightening bolts 111 (see FIG. 14) and nuts that penetrate the mounting flange 20. It is done. Further, the inner ring 14 having the second inner ring raceway 25 formed on the outer peripheral surface thereof is fitted on the small diameter step portion 22. A plurality of balls 16 and 16 are provided between the first and second outer ring raceways 18 and 19 and the first and second inner ring raceways 21 and 25, respectively, in a plurality of rows so as to freely roll. Yes.

When assembling the driving wheel supporting hub unit 10 as described above to a constant velocity joint, as shown in the figure, a spline shaft 32 (driving shaft) fixed at the center of the outer end surface 31 of the constant velocity joint outer ring 30. The male spline 33 is engaged with the female spline 23 of the hub wheel 12 by spline engagement. At the same time, the radially outer end portion of the outer end surface 31 of the constant velocity joint outer ring 30 is brought into contact with the inner end surface 34 of the inner ring 14. In this state, the nut 36 is screwed into the screw portion 35 at the tip of the spline shaft 32, and further tightened, whereby the hub wheel 12 and the inner ring 14 and the spline shaft 32 are coupled.
The male spline 33 of the spline shaft 32 has a substantially constant reference pitch outer diameter over the entire axial direction, and each tooth extends in the axial direction of the spline shaft 32 as shown in FIG. The teeth may be formed along each other, or the teeth may be twisted with respect to the axial direction of the spline shaft 32 as shown in FIG. However, when the spline shaft 32 is incorporated in the hub wheel 12, it is desirable to allow the splines 23 and 33 to have a tightening allowance. In particular, as shown in FIG. 3B, if the male spline 33 has a twist angle so as to have a tightening allowance, the assembly is easy.

  Here, the shape of the female spline 23 of the hub wheel 12, which is a feature of the present embodiment, will be described in detail. 4A is a diagram showing a cross-sectional shape along the axial direction of the female spline 23 of the hub wheel 12 of the present embodiment, and FIG. 4B is a diagram showing the female shape at each position A, B, and C in FIG. 3 is an enlarged view showing an outer shape of a spline 23. FIG. FIG. 4C is a diagram showing a cross-sectional shape along the axial direction of the female spline 23 ′ of the hub ring 12 having a uniform inner diameter of the conventional structure, and FIG. 4D is a diagram showing positions D and E in FIG. It is an enlarged view which shows the outline shape of female spline 23 '. FIG. 5 is a cross-sectional view showing the positional relationship between the female spline 23 and the male spline 33 at a position along the line IV-IV in FIG. 6A is a cross-sectional view showing the female spline 23 and the male spline 33 at a position along the line VV in FIG. 4A when torque is transmitted from the constant velocity joint. (B) is a sectional view taken along line VI-VI in FIG. 1 at that time, and (c) is a sectional view corresponding to (b) in the case of the conventional structure.

  In this embodiment, the female spline 23 of the hub wheel 12 is divided into a first female spline 40 near the outer end in the axial direction and a second female spline 41 near the inner end in the axial direction. The first female spline 40 is formed to fit with the male spline 33 of the spline shaft 32. That is, the first female spline 40 has a substantially constant reference pitch inner diameter p <b> 1 that is substantially the same as the male spline 33. On the other hand, the second female spline 41 gradually increases in the radial direction from the boundary position B with the first female spline 40 toward the axially inner end position C while gradually increasing the circumferential interval between adjacent teeth. It is formed in a taper shape that expands, and at the axial inner end position C, it is compared with the reference pitch inner diameter p1 at the axial outer end position A and the boundary position B, and the inner diameter dimensions ra1 and rb1 of the tooth bottom and the tooth tip. And a large reference pitch inner diameter p2, and inner diameter dimensions ra2 and rb2 of the tooth bottom and the tooth tip. In FIG. 4, ra1 and rb1 indicate substantially constant inner diameter dimensions of the tooth bottom and the tooth tip from the axial outer end position A to the boundary position B with the second female spline 41, and ra2 and rb2 The inner diameter dimensions of the tooth bottom and the tooth tip at the axially inner end position C, which are larger than the inner diameter dimensions ra1 and rb1 of the tooth bottom and the tooth tip, are shown.

Compared to the root cross-sectional shape R1 of the first female spline 40 at the axial outer end position A and the boundary position B, the root cross-sectional shape R2 of the second female spline 41 at the axial inner end position C is , Have a slightly larger radius of curvature. Thereby, as shown in FIG. 5, the radial and circumferential clearances of the second female spline 41 with the male spline 33 of the spline shaft 32 gradually increase.
On the other hand, the conventional structure in which the reference pitch inner diameter p1 of the female spline 23 'of the hub wheel 12 is uniform over the entire axial direction of the axial outer end position D and the axial inner end position E is shown in FIG. And as shown in (d), it has the same spline shape in each position D and E.
Note that the second female spline 41 of the present embodiment is completely different from the adjacent chamfered portion 24, and the axial length L1 of the second female spline 41 is the axial length L2 of the chamfered portion 24. The radial length L3 of the second female spline 41, which is longer and is the difference between the reference pitch inner diameters at the boundary position B and the axial inner end position C, is the difference between the inner diameters at both axial ends. It is 1/50 or less of radial direction length L4 in a part.

  Therefore, when torque is transmitted from the constant velocity joint, the male spline 33 on the constant velocity joint side comes into contact with the female spline 23 of the hub wheel 12 while being elastically deformed. Here, in the case of the conventional structure, as shown in FIG. 6C, force acts only on a part of the contact range C2 and stress concentration occurs. However, in this embodiment, the torque increases. However, as shown in FIG. 6 (b), the contact range C1 is wide, and no force is applied to a part of the contact range C1, so that stress concentration does not occur and the structure is advantageous in terms of strength.

  Further, the boundary position B of the first and second female splines 40 and 41 is arranged between the center positions O1 and O2 of the double row rolling elements 16 and 16, as shown in FIG. When the boundary position B is closer to the inner end in the axial direction than the center position O2 of the ball 16 on the inner end side in the axial direction, the radial and circumferential clearances between the second female spline 41 and the male spline 33 remain small. Not much different from the structure, when torque is transmitted and the male spline 33 is elastically deformed, the contact range is narrow, so stress concentration is likely to occur in the female spline 23. Further, if the boundary position B is closer to the outer end in the axial direction than the center position O1 of the ball 16 on the outer end side in the axial direction, the length of the first female spline 40 is shortened. Misalignment tends to occur.

  Further, as shown in FIG. 5, the radial length L3 of the second female spline 41 is equal to the male spline 33 of the spline shaft 32 and the hub at the reference pitch diameter position at the axial inner end position C of the female spline 41. It is smaller than the circumferential clearance C (= C1 + C2) between the ring 12 and the female spline 23. When the radial length L3 becomes larger than the circumferential clearance C, even when the male spline 33 is elastically deformed when torque is transmitted from the constant velocity joint, the splines 33 and 23 contact each other at the tip of the female spline 23. Since it does not occur, the contact range becomes narrow and stress concentration tends to occur. Further, since the gap becomes large, the spline is easily deformed and high stress is easily generated.

  Specifically, in the above embodiment, the spline 40, 33 has a reference pitch diameter of about 30 mm, and the gap at the axially inner end position C is increased by about 23 μm in diameter, so that the effect of the present invention is achieved. Obtained. According to the calculation using the finite element method, when the constant velocity joint is torqued in the direction of arrow F in FIG. 6, the stress generated in the tooth bottom of the female spline 23 of the hub wheel 12 is reduced by about 10%. I was able to. In addition, the magnitude | size expanded in the axial direction inner end position C is not limited to this value, It can set suitably in the range with the effect.

(Second Embodiment)
Next, the driving wheel supporting hub unit 10a according to the second embodiment of the present invention will be described in detail with reference to FIGS. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified.

  In the present embodiment, the male spline 33a of the spline shaft 32a is formed in a tapered shape having a predetermined inclination angle over the entire axial direction. Therefore, as shown in FIG. 10, the first female spline 40a is formed in a tapered shape having an inclination angle α1 substantially equal to the predetermined inclination angle of the male spline 33a, and the second female spline 41a is The first female spline 40a is formed in a tapered shape having an inclination angle α2 larger than the inclination angle α1.

In the male spline 33a of the tapered spline shaft 32a, as shown in FIG. 9, the circumferential interval between adjacent teeth gradually increases from the axial outer end position toward the axial inner end position. For this reason, also in the 1st female spline 40a, the circumferential direction space | interval of an adjacent tooth | gear spreads gradually toward the boundary position B from the axial direction outer end position so that this male spline 33a may be fitted. Further, in the second female spline 41a, the circumferential interval between adjacent teeth gradually increases from the boundary position B toward the axial inner end position C to a degree greater than the degree of expansion of the first female spline 40a.
As a result, the second female spline 41a has a radial and circumferential clearance from the boundary position B with the first female spline 40a toward the axial inner end position C of the spline shaft 32a with the male spline 33a. It is formed in a tapered shape so as to gradually increase.

  Further, the root cross-sectional shape R2 of the second female spline 41a gradually increases in radius of curvature from the boundary position B to the axial inner end position C. The root cross-sectional shape R1 of the first female spline 40a may have a constant radius of curvature from the axial outer end position A to the boundary position B as long as the male spline 33a is fitted to the first spline 40a. It may be made larger.

Therefore, also in this embodiment, a large torque is transmitted from the constant velocity joint, and the contact range becomes wide when the male spline 33a on the constant velocity joint contacts the female spline 23a of the hub wheel 12 while elastically deforming. The stress is not concentrated and the structure is advantageous in terms of strength.
Other configurations and operations are the same as those in the first embodiment.

In addition, this invention is not limited to embodiment mentioned above, A change, improvement, etc. are possible suitably.
For example, in each of the above embodiments, the case where the present invention is applied to the third generation drive wheel supporting hub units 10 and 10a has been described. However, as in the first modification shown in FIG. It may be applied to the second generation drive wheel supporting hub unit bearings 50, 50 a in which the small diameter step portion 22 is formed in the intermediate portion in the axial direction and the pair of inner rings 13, 14 are externally fitted. Alternatively, according to the present invention, as in the second modification shown in FIG. 12, the outer ring member 11a does not have the flange portion 17, and the first generation driving wheel supporting hub unit bearing 60 in which the knuckle 107 is externally fitted. , 60a.
Further, according to the present invention, as in the third modified example shown in FIG. 13, the front end portion of the hub wheel 12 to which the inner ring 14 is externally fitted near the inner end in the axial direction is caulked and spread outward in the radial direction. You may apply to the hub unit bearing 70,70a of the 3rd generation drive wheel support which formed the part 71. FIG. In this case, the radially outer end portion of the outer end surface 31 of the outer ring 30 for the constant velocity joint is brought into contact with the inner end surface 72 of the hub wheel 12 constituting the caulking portion 71.

It is sectional drawing shown in the state with which the hub unit for driving wheel support which concerns on 1st Embodiment of this invention was assembled | attached with the constant velocity joint. It is sectional drawing which shows the hub unit for driving wheel support of FIG. (A) is a side view which shows an example of the shape of the male spline of the spline shaft of FIG. 1, (b) is a side view which shows the other example of the shape of the male spline of a spline shaft. (A) is a longitudinal cross-sectional view of the shape of the female spline of the hub ring of this embodiment, (b) is an enlarged view showing the outline shape of the female spline at each position of (a), (c) These are the longitudinal cross-sectional views which show the female spline of the hub ring of the uniform internal diameter of a conventional structure, (d) is an enlarged view which shows the outline shape of the female spline in each position of (c). It is sectional drawing which shows the positional relationship of a female spline and a male spline in the position along the IV-IV line | wire of Fig.4 (a). (A) is sectional drawing which shows a female spline and a male spline in the position along the IV-IV line | wire of Fig.4 (a) when torque is transmitted from a constant velocity joint, (b) FIG. 5 is a cross-sectional view taken along line VI-VI in FIG. 1 at that time, and FIG. 6C is a cross-sectional view corresponding to FIG. It is sectional drawing shown in the state with which the hub unit for driving wheel support which concerns on 2nd Embodiment of this invention was assembled | attached with the constant velocity joint. It is sectional drawing which shows the hub unit for driving wheel support of FIG. (A) is a side view which shows an example of the shape of the male spline of the spline shaft of FIG. 7, (b) is a side view which shows the other example of the shape of the male spline of a spline shaft. (A) is a longitudinal cross-sectional view of the shape of the female spline of the hub ring of this embodiment, and (b) is an enlarged view showing the outer shape of the female spline at each position of (a). (A) is sectional drawing which shows the hub unit for driving wheel support which concerns on the 1st modification of 1st Embodiment of this invention, (b) is a 1st modification of 2nd Embodiment of this invention. It is sectional drawing which shows the hub unit for this driving wheel support. (A) is sectional drawing which shows the hub unit for driving wheel support which concerns on the 2nd modification of 1st Embodiment of this invention, (b) is a 2nd modification of 2nd Embodiment of this invention. It is sectional drawing which shows the hub unit for this driving wheel support. (A) is sectional drawing which shows the hub unit for driving wheel support which concerns on the 3rd modification of 1st Embodiment of this invention, (b) is a 3rd modification of 2nd Embodiment of this invention. It is sectional drawing which shows the hub unit for this driving wheel support. It is sectional drawing which shows the conventional hub unit for driving wheel support.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Drive wheel support hub unit 11 Outer ring member 12 Hub ring 13, 14 Inner ring 15 Hub 16 Rolling element 18 First outer ring track 19 Second outer ring track 20 Mounting flange 21 First inner ring track 25 Second inner ring track 22 Small diameter step part 23 Female spline 30 Outer ring for constant velocity joint 32 Spline shaft (drive shaft)
33 Male spline 36 Nut 40 First female spline 41 Second female spline

Claims (5)

An outer ring member having first and second outer ring raceways on the inner peripheral surface;
A hub wheel having a flange for supporting a wheel at a portion near the outer end in the axial direction, and a female spline that can be coupled with a male spline formed on the outer peripheral surface of the drive shaft, formed on the inner peripheral surface, and the hub wheel A hub that forms first and second inner ring raceways opposed to the first and second outer ring raceways,
Between the first and second outer ring raceways and the first and second inner ring raceways, a plurality of rolling elements each provided in multiple rows,
In a drive wheel support hub unit comprising:
The female spline of the hub wheel is divided into a first female spline near the outer end in the axial direction and a second female spline near the inner end in the axial direction,
The first female spline is formed so as to fit with the male spline of the drive shaft,
In the second female spline, the radial and circumferential clearances with the male spline of the drive shaft gradually increase from the boundary position with the first female spline toward the inner end position in the axial direction. A hub unit for supporting a driving wheel, wherein the hub unit is formed in a tapered shape. The boundary position between the first and second female splines is disposed between the center positions of the double row rolling elements,
The radial length of the second female spline is the circumferential direction between the male spline of the drive shaft and the female spline of the hub wheel at the reference pitch diameter position at the axially inner end position of the second female spline. The drive wheel support hub unit according to claim 1, wherein the hub unit is a drive wheel support hub unit. The male spline of the drive shaft has a substantially constant reference pitch outer diameter over the entire axial direction,
The hub unit for supporting driving wheels according to claim 1 or 2, wherein the first female spline has a reference pitch inner diameter substantially the same as a reference pitch outer diameter of the male spline. The male spline of the drive shaft is formed in a tapered shape having a predetermined inclination angle over the entire axial direction,
The first female spline is formed in a tapered shape having an inclination angle substantially equal to a predetermined inclination angle of the male spline,
3. The drive wheel support hub unit according to claim 1, wherein the second female spline is formed in a tapered shape having an inclination angle larger than an inclination angle of the first female spline. 4. On the inner peripheral surface of the hub wheel, a chamfered portion is formed closer to the inner end in the axial direction than the second female spline,
The axial length of the second female spline is longer than the axial length of the chamfered portion,
5. The drive wheel support hub unit according to claim 1, wherein the radial length of the second female spline is 1/50 or less of the radial length of the chamfered portion. .

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