JP5304113B2 - Axle bearing fastening structure - Google Patents

Description

  The present invention relates to a fastening structure using nuts between a hub wheel and a drive shaft of an axle bearing that supports a drive wheel of an automobile or the like.

Front wheel of FF vehicle (front engine front wheel drive vehicle), rear wheel of FR vehicle (front engine rear wheel drive vehicle), rear wheel of RR vehicle (rear engine rear wheel drive vehicle) and 4WD (four wheel drive vehicle) In wheel bearings for supporting the driving wheels of automobiles such as all wheels, unitization for further increasing rigidity for steering stability is rapidly progressing.
The conventional axle bearings that support unitized drive wheels are spline-fitted from the vehicle inner side into the shaft hole at the center of the hub wheel, and the drive shaft and hub wheel rotate as a unit. Is configured to do.

The drive shaft is, for example, a constant velocity joint. In this case, the body portion has a large diameter and the tip side has a small diameter, a spline is formed on the base side of the small diameter portion, and a screw portion is formed on the tip side. This is spline-fitted into the shaft hole of the hub wheel, and the hub receiving surface of the vehicle outer side end surface of the large diameter portion is brought into contact with the vehicle inner side end surface of the hub wheel.
Then, the nut is screwed onto the screw portion at the tip of the drive shaft, thereby pressing the nut against the nut receiving portion which is the vehicle outer side end portion of the hub wheel, and the hub wheel is pivoted by this nut and the hub receiving surface. By sandwiching from the direction, the hub wheel and the drive shaft are integrated.

JP 2008-74357 A (first page, FIG. 1)

By the way, when a nut is screwed into the threaded portion at the tip of the drive shaft, a nut with a seating surface is generally used as the nut, and the seating surface of the nut with a seating surface is flat and the vehicle outer of the hub wheel. The nut receiver formed on the side end is also a flat surface.
For this reason, even if the tightening torque of the nut with the seating surface is constant due to the surface roughness, parallelism, and flatness of the seating surface of the nut with the seating surface and the seating surface of the hub, There are cases where it is difficult to ensure a stable quality fastening structure when assembling the vehicle, for example, the force is not constant and the axial force generated on the drive shaft such as a hub or constant velocity joint (CVJ) varies, resulting in reduced bearing performance. there were.
The present invention has been made in order to solve such a problem. The fastening force of the nut is constant, the axial force generated in the hub and the drive shaft does not vary, and the fastening structure has a stable quality when the vehicle is assembled. Fastening structure for axle bearings that can ensure.

  The fastening structure of the axle bearing according to the present invention includes a hub wheel having a hub flange formed on the outer peripheral surface on the outer side, and a concentric arrangement so as to be relatively rotatable with respect to the hub wheel, and is non-rotating on the vehicle body side. On the outer side of the shaft hole of the shaft portion of the hub wheel of the axle bearing provided with the outer ring to be attached, a concave nut that accommodates a seated nut screwed to the screw portion of the drive shaft inserted through the shaft hole A receiving portion is formed, and a nut receiving seat surface of the nut receiving portion is formed in a shape so as to be in line contact with a nut seating surface of the seated nut, and the seated nut is formed on a screw portion of a drive shaft located in the nut receiving portion. And tighten the hub wheel and the drive shaft with the seated nuts so that the nut seat surface abuts against the nut seat surface of the nut receiving portion. One in which the.

  Further, another axle bearing fastening structure according to the present invention includes a hub wheel in which a hub flange attached to a wheel is formed on the outer peripheral surface of the outer side, and a concentrically disposed so as to be relatively rotatable with respect to the hub wheel. On the outer side of the shaft hole of the shaft portion of the hub wheel of the axle bearing having an outer ring attached non-rotatably on the side, a seated nut screwed into the screw portion of the axle inserted through the shaft hole is accommodated And a nut receiving seat surface of the nut receiving portion is formed into a hemispherical concave shape, and a nut seating surface of the nut with the seat is processed into a hemispherical convex shape, and the hemispherical concave shape of the nut receiving portion is formed. The radius of curvature of the nut receiving surface of the nut is set to be larger than the radius of curvature of the hemispherical convex nut seat surface of the nut with seat, and the seat is attached to the screw portion of the drive shaft located in the nut receiving portion And screwing the nut with the seat so that the hemispherical convex nut seating surface comes into contact with the hemispherical concave nut seating surface of the nut receiving portion, and the hub wheel and the drive shaft with the seated nut. Is concluded.

  In the fastening structure for an axle bearing according to the present invention, the nut receiving seat surface of the concave nut receiving portion formed on the outer side of the shaft hole of the shaft portion of the hub wheel is in line contact with the nut seat surface of the seated nut. The nut receiving seat surface of the concave nut receiving portion is processed and formed into a hemispherical concave shape, and the nut seating surface of the seated nut is processed into a hemispherical convex shape, and the hemispherical concave nut receiving seat of the nut receiving portion is formed. The radius of curvature of the surface is set to be larger than the radius of curvature of the hemispherical convex nut seat surface of the seated nut, and the seated nut is screwed into the threaded portion of the axle located in the concave nut receiving portion of the hub wheel. Tighten the seated nut so that its hemispherical convex nut seating surface comes into contact with the hemispherical concave nut receiving seating surface of the concave nut receiving part, and fasten the hub wheel and drive shaft with the seated nut. Therefore, the nut seat surface of the nut with the seat is in line contact with the nut seat surface of the concave nut receiving portion of the hub wheel, so that the contact state is stable because the one-sided contact is lost, and the fastening force of the nut becomes constant. The axial force generated on the drive shaft such as a speed joint does not vary, and the contact area is reduced compared to conventional surface contact and the tightening force per unit area is increased, so that stable quality can be achieved when assembling the vehicle. There is an effect that a fastening structure can be secured.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing a state before a nut with a seating surface is fastened to an axle inserted into a hub wheel, and FIG. FIG. 3 is a cross-sectional view showing a state in which a nut with a seating surface is fastened to an axle inserted in a hub wheel, and FIG. 3 is an enlarged cross-sectional view of a part of FIG. In each figure, the upper side is the vehicle outer side, and the lower side is the vehicle inner side.
In FIG. 1, an inner ring rotating type hub unit 1 having an axle bearing fastening structure according to Embodiment 1 of the present invention includes an outer ring 2, a hub wheel 3, a separate inner ring 4, and a rolling element group 5. It is configured to be used by being mounted on the axle 10.

The hub wheel 3 includes a cylindrical shaft portion 31 formed of carbon steel or bearing steel, and a wheel mounting hub flange 32 provided on the outer peripheral surface of the shaft portion 31 on the vehicle outer side. And arranged concentrically with the outer ring 2.
An inner ring 4 is fitted on the outer peripheral surface of the end portion on the vehicle inner side of the shaft portion 31 of the hub wheel 3. Two rows of rolling element groups 5 are arranged in the axial direction between the outer peripheral surface of the shaft portion 31 of the hub wheel 3 on the vehicle inner side and between the inner ring 4 and the outer ring 2. The rolling elements are balls or tapered rollers made of bearing steel, ceramics, or the like, and a plurality of rolling elements are arranged side by side in the circumferential direction.

The outer ring 2 is attached non-rotatingly to the vehicle body side. The outer ring 2 is formed of carbon steel or bearing steel, has two rows of raceway surfaces on the inner peripheral surface, is formed so that the outer ring flange portion 21 protrudes radially on the outer peripheral surface, and has a bolt insertion hole in the axial direction. 21a is formed.
Bolts 23 are inserted into the bolt insertion holes 21a, and the outer ring 2 is fixed to the knuckle 8 on the vehicle body side. By fixing the outer ring 2 to the knuckle 8, the hub unit 1 is fixed to the vehicle body.
The separate inner ring 4 is made of carbon steel or bearing steel, and is press-fitted to the outer peripheral surface of the end portion on the vehicle inner side of the hub wheel 3.

A hub bolt insertion hole 32a is formed in the axial direction in the hub flange 32 provided on the outer peripheral surface of the shaft portion 31 of the hub wheel 3 on the vehicle outer side.
A hub bolt 35 is press-fitted into the hub bolt insertion hole 32 a of the hub flange 32. The brake disc rotor 7 and the tire wheel 6 are attached to the surface of the hub flange 32 on the vehicle outer side by tightening a hub bolt 35 and a nut (not shown).

A spline portion 10a is formed on the vehicle inner side of the axle 10 to be inserted into the shaft hole 31a of the shaft portion 31 of the hub wheel 3, a screw portion 10b is formed on the vehicle outer side, and a vehicle inner side end portion is formed. A constant velocity joint 14 as a drive shaft is attached.
On the vehicle outer side of the shaft hole 31a of the shaft portion 31 of the hub wheel 3, a concave nut receiving portion 17 that accommodates a seated nut 16 that is a fastening member screwed into the screw portion 10b of the axle 10 is formed. .
A nut receiving seat surface 17a, which is the bottom of the nut receiving portion 17, is formed into a hemispherical concave shape. Moreover, the nut seat surface 16a of the nut 16 with a seat is processed and formed in a hemispherical convex shape.
The radius of curvature of the hemispherical concave nut receiving seat surface 17a of the nut receiving portion 17 is set to be larger than the radius of curvature of the hemispherical convex nut seating surface 16a of the nut 16 with seat.
The hemispherical concave shape of the nut receiving seat surface 17a and the hemispherical convex shape of the nut seating surface 16a may each be constituted by a single curvature radius surface, or may be constituted by combining a plurality of curvature radius surfaces. It is sufficient that the radius of curvature has the above relationship in the contact portion of the hemispherical concave shape of the nut receiving seat surface 17a and the hemispherical convex shape of the nut seating surface 16a.

Next, the case where the seated nut 16 is fastened to the axle 10 inserted into the shaft hole 31a of the shaft portion 31 of the hub unit 1 will be described.
First, when the axle 10 to which the constant velocity joint 14 is attached is inserted into the shaft hole 31 a of the hub unit 1, the vehicle inner side end 4 a of the separate inner ring 4 of the hub unit 1 and the constant velocity joint 14 of the axle 10. The vehicle outer side end surface 14a contacts.
Next, the seated nut 16 is screwed into the threaded portion 10b of the axle 10 positioned in the concave nut receiving portion 17 of the shaft portion 31 of the hub wheel 3, and the seated nut 16 is received by the nut receiving surface 16a of the nut. The nut 17 is tightened so as to be in contact with the hemispherical concave nut receiving surface 17a. Then, the vehicle outer side end surface 14 a of the constant velocity joint 14 is pressed against the vehicle inner side end surface 4 a of the separate inner ring 4, and the pressed state is maintained by the tightened nut 16 with the seat, and the axle 10 is the axis of the hub wheel 3. The shaft 31 is coupled to the shaft hole 31a of the portion 31 in the axial direction.

  In the first embodiment, the nut receiving seat surface 17a of the concave nut receiving portion 17 formed on the vehicle outer side of the shaft hole 31a of the shaft portion 31 of the hub wheel 3 is processed and formed into a hemispherical concave shape. The nut seat surface 16a is processed and formed into a hemispherical convex shape, and the radius of curvature of the hemispherical concave nut receiving seat surface 17a of the nut receiving portion 17 is larger than the radius of curvature of the hemispherical convex nut seating surface 16a of the seated nut 16. Thus, the seated nut 16 is screwed into the threaded portion 10b of the axle 10 located in the concave nut receiving portion 17 of the hub wheel 3, and the seated nut 16 is a nut having a concave nut seat surface 16a. When tightened so as to abut on the hemispherical concave nut receiving surface 17a of the receiving portion 17, it is seated against the nut receiving surface 17a of the concave nut receiving portion 17 of the hub wheel 3. As shown in FIG. 3, the nut seat surface 16a of the nut 16 is in line contact, and the contact state is eliminated, the contact state is stabilized, the fastening force of the nut is constant, and the axle 10 to which the constant velocity joint 14 is connected. The generated axial force does not vary, and the contact area is reduced compared to conventional surface contact and the tightening force per unit area is increased, thereby ensuring a stable fastening structure when assembling the vehicle. it can.

Embodiment 2. FIG.
FIG. 4 is an axle bearing according to Embodiment 2 of the present invention, and is a partial sectional view showing a state before a nut with a seating surface is fastened to an axle inserted into a hub wheel, and FIG. 5 is an axle bearing. FIG. 6 is a partial cross-sectional view showing a state in which a nut with a seating surface is fastened to an axle inserted in the hub wheel, and FIG. 6 is an enlarged cross-sectional view of a part of FIG.
4 to 6, the same components as those in the first embodiment are denoted by the same reference numerals, and the description of the overlapping components is omitted.
In the second embodiment, the shape of the nut receiving seat surface 17a of the concave nut receiving portion 17 formed on the vehicle outer side of the shaft hole 32 of the hub wheel 3 is different from that of the first embodiment.

In the second embodiment, the nut receiving seat surface 17a of the concave nut receiving portion 17 formed on the vehicle outer side of the shaft hole 31a of the shaft portion 31 of the hub wheel 3 is formed into a tapered shape.
Moreover, the nut seat surface 16a of the nut 16 with a seat is processed and formed in a hemispherical convex shape.
Then, a nut 16 with a seat is screwed into a threaded portion 10b of the axle 10 located in the concave nut receiving portion 17 of the hub wheel 3, and the nut 16 having a hemispherical convexity is provided with a concave nut receiving portion. FIG. 6 shows the nut seat surface 16a of the seated nut 16 with respect to the nut seat surface 17a of the concave nut seat portion 17 of the hub wheel 3 when tightened so as to abut on the 17 tapered nut seat surface 17a. Thus, it is configured to be in line contact.
In this way, the tapered nut receiving surface 17a of the concave nut receiving portion 17 is also in line contact with the hemispherical convex nut seating surface 16a of the seated nut 16 as in the first embodiment. It is included in one of the specific examples.
The nut receiving seat surface 17a is tapered. However, the nut receiving seat surface 17a may be configured by combining a tapered shape and a hemispherical concave shape. In this case, the nut receiving seat surface 17a has a hemispherical concave shape and a nut seating surface. It is sufficient that the radius of curvature of the hemispherical convex contact portion 16a is set so that the nut receiving seat surface 17a is larger than the nut seating surface 16a.

  The second embodiment also has the same operations and effects as the first embodiment, but the advantage of the second embodiment is that the nut receiving seat surface 17a of the concave nut receiving portion 17 is formed into a tapered shape. This means that the processing is easier than the case where the nut receiving seat surface 17a of the nut receiving portion 17 of the eleventh embodiment is processed and formed into a hemispherical concave shape.

In the first and second embodiments, when the nut receiving seat surface 17a of the concave nut receiving portion 17 and the nut seating surface 16a of the seated nut 16 are in line contact, the inner diameter side / outer diameter side of these both seat surfaces Both of them are not per edge and have a clearance of about 0.05 to 0.10 mm, but the inner diameter portion of the nut receiving seat surface 17a of the nut receiving portion 17 and the nut seating surface of the nut 16 with seat. If the outer diameter portion of 16a is chamfered in an R shape, a gap on the inner diameter side / outer diameter side of both seat surfaces can be further secured, and the line contact between the two can be further ensured.
In the first and second embodiments, the constant velocity joint is used as the drive shaft (the drive mechanism having the constant velocity joint). Needless to say.

Sectional drawing which shows the state before the nut with a seat surface is fastened to the axle shaft inserted by the hub wheel by the fastening structure of the axle bearing of Embodiment 1 of this invention. Sectional drawing which shows the state by which the nut with a seat surface was fastened by the axle structure inserted in the hub wheel by the fastening structure of the bearing for the said axle shafts. Sectional drawing which expanded a part of FIG. The fragmentary sectional view which shows the state before the nut with a seat surface is fastened to the axle shaft inserted in the hub wheel in the fastening structure of the axle bearing according to the second embodiment of the present invention. The fragmentary sectional view which shows the state by which the nut with a seat surface was fastened by the axle structure inserted in the hub wheel by the fastening structure of the bearing for axles. Sectional drawing which expanded a part of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Hub unit, 2 outer ring, 3 hub wheel, 4 separate inner ring, 4a vehicle inner side end surface, 5 rolling element group, 6 tire wheel, 7 brake disk rotor, 8 knuckle, 10 axle, 10a spline part, 10b screw part, 14 constant velocity joint, 14a vehicle outer side end surface, 16 seated nut, 16a nut seat surface, 17 nut receiving portion, 17a net receiving seat surface, 21 outer ring flange portion, 21a bolt insertion hole, 31 shaft portion, 31a shaft hole, 32 Hub flange, 32a Hub bolt insertion hole, 35 Hub bolt.

Claims (2)

The hub of an axle bearing having a hub wheel having a hub flange formed on the outer peripheral surface of the outer side, and an outer ring that is concentrically disposed so as to be relatively rotatable with respect to the hub wheel and mounted non-rotatably on the vehicle body side. On the outer side of the shaft hole of the shaft portion of the wheel, a concave nut receiving portion is formed that accommodates a seated nut that is screwed into the screw portion of the drive shaft inserted through the shaft hole, and the nut of the nut receiving portion is formed. The receiving seat surface is formed in a shape that makes line contact with the nut seat surface of the seated nut,
The seated nut is screwed into the threaded portion of the drive shaft located in the nut receiving portion, and the seated nut is tightened so that the nut seating surface comes into contact with the nut receiving seating surface of the nut receiving portion. A fastening structure for an axle bearing, wherein a hub wheel and the drive shaft are fastened. The hub of an axle bearing having a hub wheel having a hub flange formed on the outer peripheral surface of the outer side, and an outer ring that is concentrically disposed so as to be relatively rotatable with respect to the hub wheel and mounted non-rotatably on the vehicle body side. On the outer side of the shaft hole of the shaft portion of the wheel, a concave nut receiving portion is formed that accommodates a seated nut that is screwed into the screw portion of the drive shaft inserted through the shaft hole, and the nut of the nut receiving portion is formed. The receiving surface is formed into a hemispherical concave shape,
The nut seat surface of the seated nut is formed into a hemispherical convex shape,
The radius of curvature of the hemispherical concave nut receiving seat surface of the nut receiving portion is set to be larger than the radius of curvature of the hemispherical convex nut seating surface of the nut with seat,
The seated nut is screwed into the threaded portion of the drive shaft located in the nut receiving portion, and the hemispherical convex nut seat surface of the seated nut is in contact with the hemispherical concave nut receiving seat surface of the nut receiving portion. A fastening structure for an axle bearing, wherein the hub wheel and the drive shaft are fastened by tightening and the nut with a seat.

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