JP5088658B2 - Hub unit - Google Patents

Description

  The present invention relates to a hub unit used by being mounted on an axle.

  The rolling bearing device for driving wheel support is configured such that the axle (drive shaft) is spline-fitted from the vehicle inner side to the shaft hole at the center of the hub wheel so that the axle and the hub wheel rotate together.

  More specifically, the axle has a large diameter body and a small diameter on the tip side, a spline is formed on the base side of the small diameter portion, and a screw part is formed on the tip side. The hub receiving surface of the vehicle outer side end surface of the large-diameter portion of the axle is brought into contact with the vehicle inner side end surface of the inner ring. Then, the nut is screwed onto the screw portion at the tip of the axle so that the nut is pressed against the vehicle outer side end of the hub wheel, and the hub wheel and the inner ring are sandwiched from the axial direction by the nut and the hub receiving surface. Thus, the hub wheel, the axle, and the inner ring are integrated.

  Further, a hub flange is formed on the outer peripheral surface of the hub wheel so as to protrude in the radial direction from the vehicle outer side end portion. A hub bolt insertion hole is formed in the hub flange, and a hub bolt that projects through the hub flange from the vehicle outer side main surface of the hub flange to the brake disc rotor and the tire wheel side is provided. By tightening the hub bolt and the hub nut, the brake disk rotor and the tire wheel of the brake device are attached in this order on the main surface of the hub flange on the vehicle outer side.

  The hub bolt is formed with a press-fit fixing serration portion in the circumferential direction on the outer peripheral surface of the base end side of the bolt shaft portion so that slipping does not occur when the hub bolt is press-fitted into the hub flange and fastened. The hub bolt is attached in such a manner that the bolt head is brought into contact with the peripheral edge of the bolt insertion hole of the hub flange while the serration portion is press-fitted into the bolt insertion hole.

  However, if the bolt surface hardness is increased in order to improve the biting of the serration portion of the hub bolt, there may be a case where varicus (burr dropout) occurs during press-fitting into the hub flange. When the varicus is generated, the varicus may fall in the assembly process and cause the quality of the product to deteriorate. For example, when the varicus falls on the hub bolt press-fitting base and is sandwiched between the workpiece and the workpiece, the workpiece may be indented.

  The present invention has been made in view of the above problems, and provides a hub unit that can suppress the occurrence of burrs in the axial direction and eliminate the burrs from dropping even when the hardness of the hub bolt is high. It is in.

In order to solve the above-described problems, the hub unit of the present invention includes:
An outer ring that is used by being attached to the vehicle outer side end of the axle and is non-rotatably attached to the vehicle body side, a hub wheel that is concentrically arranged with the outer ring and has a wheel mounting flange formed in the circumferential direction, and a hub wheel A hub unit including at least an inner ring that is fitted to the outer peripheral surface of the vehicle inner side end portion, and a rolling element row that includes a plurality of rolling elements arranged in the circumferential direction between the inner ring or hub wheel and the outer ring In
On the wheel mounting flange, a bolt insertion hole for press-fitting the wheel mounting bolt is formed so as to penetrate in the axial direction. On the outer peripheral surface of the wheel mounting bolt on the proximal end side of the shaft portion, a press-fitting serration portion Is formed in the circumferential direction, and the bolt head formed on the base end side is brought into contact with the periphery of the bolt insertion hole on the vehicle inner side main surface side while press-fitting the press-fit fixing serration portion into the bolt insertion hole. Mounted in shape,
While the Rockwell C scale hardness of the portion including the inner peripheral surface of the bolt insertion hole of the steel material constituting the wheel mounting flange is adjusted to HRC18 or more and HRC28 or less, the press fitting fixing serration portion of the steel material constituting the wheel mounting bolt The Vickers hardness of the part including Hv400 is Hv400 or more and Hv500 or less, and the opening peripheral part of the bolt insertion hole on the vehicle outer side main surface which is the protruding side of the wheel mounting bolt is expanded at the outer side taper part. The vehicle outer side edge of the serration portion for press-fitting and fixing is positioned so as to be retracted to the vehicle inner side of the vehicle inner side edge of the outer taper portion.

  The hub is carbon steel, and the periphery of the bolt hole has the above hardness in a cold forged state. On the other hand, although the bolt is a carbon hole, it is carburized and quenched for imparting wear resistance, and the Vickers hardness is Hv400 (however, the measurement load is 300 g) or more. High wear resistance. Further, by adjusting the press-fitting serration portion in the same manner, it is possible to surely bite into the inner peripheral surface of the hub side bolt hole, which is softer than this, and the press-fit fixing strength is improved. And by setting the upper limit of the hardness to Hv500 or less and sinking the serration part rather than the taper, excessive galling of the inner peripheral surface of the bolt hole by the serration part is suppressed, and burrs due to galling are exposed to the taper part. Is prevented.

  Below HRC18, the strength of the flange becomes insufficient, and when it exceeds HRC28, it is difficult to press-fit the bolt. If it is less than 400, serrations are lost at the time of press-fitting, leading to insufficient press-fitting, and if it exceeds 500, burrs are generated.

  In the hub unit of the present invention, the opening peripheral edge portion of the bolt insertion hole to the vehicle inner side main surface is enlarged in diameter by the inner side taper portion, and the axial direction forming width of the inner side taper portion is the outer side. The width can be set larger than the axial width of the tapered portion. According to this structure, it becomes a structure which is easy to prevent a burr | flash from dropping off.

  In the hub unit of the present invention, the retraction length of the vehicle outer side end edge of the press-fit fixing serration portion from the vehicle inner side end edge of the outer side tapered portion to the vehicle inner side may be 0.5 mm or more and 6 mm or less. it can. If the retracted length of the outer taper portion is at least 0.5 mm or less, the occurrence of burrs can be reliably prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of a hub unit of the present invention and a mounting structure in which the hub unit is attached to an axle, and FIG. 2 is an enlarged view of a hub flange 33 and a hub bolt portion in FIG. is there. In both figures, the left side is the vehicle outer side, and the right side is the vehicle inner side. As shown in FIG. 1, the hub unit 1 of the present invention includes an outer ring 2, a hub wheel 3, an inner ring 4, and rolling element rows 5 (5 a, 5 b), and is attached to an axle 10. used.

  The hub wheel 3 includes a shaft portion 30 and a wheel mounting flange (hereinafter referred to as a hub flange) 33 that fixes a tire wheel 6 of a wheel and a brake disc rotor 7 of a brake device, and is concentric with the outer ring 2. And a tire wheel (wheel) 6 and a brake disc rotor 7 are attached and rotate integrally therewith. The inner ring 4 is fitted on the outer peripheral surface of the vehicle inner side end of the shaft portion 30, and the rolling element rows 5, 5 are arranged between the inner ring 4 and the hub wheel 3 and the outer ring 2 in a double row.

  The rolling element row 5 is composed of a plurality of rolling elements arranged in the circumferential direction between the inner ring 4 or the hub wheel 3 and the outer ring 2, and a plurality of rolling element arrays are arranged in the axial direction. The rolling element row 5 in the present embodiment is arranged in two rows (5a, 5b) between the inner ring 4 and the hub wheel 3 and the outer ring 2.

  The outer ring 2 is attached non-rotatingly to the vehicle body side. The outer ring 2 is made of carbon steel hot forging, has a raceway surface in a double row on the inner periphery, an outer ring flange portion 23 is formed projecting in the radial direction on the outer periphery surface, and a bolt insertion hole 23a is formed in the axial direction. Has been. The bolt 26 is inserted into the bolt insertion hole 23a, and the outer ring 2 is fixed to the knuckle 8 on the vehicle body side with the back plate 51 and the end plate 52 interposed therebetween. By fixing the outer ring 2 to the knuckle 8, the hub unit 1 is fixed to the vehicle body.

  The inner ring 4 is press-fitted and fitted to at least a small-diameter outer peripheral surface 31 a of the vehicle inner side end 31 of the hub wheel 3. The inner ring 4 is formed as a protruding portion (thick portion) 41 that is larger in diameter than the inner ring main body portion 40 positioned on the vehicle outer side and protrudes in the axial direction, and a vehicle inner side end surface 41b of the protruding portion 41 is formed in the vehicle. It is a bearing surface.

  The shaft portion 30 of the hub wheel 3 has a shaft hole 32 penetrating in the axial direction, and a hub flange 33 at an end portion on the vehicle outer side. As shown in FIG. 2, a hub bolt insertion hole 33a for press-fitting a hub bolt (hereinafter referred to as a hub bolt) 36 is formed in the hub flange 33 so as to penetrate in the axial direction. As for the steel material which comprises this hub flange 33, the Rockwell C scale hardness of the part including the inner peripheral surface of the hub bolt insertion hole 33a is adjusted to HRC18 or more and HRC28 or less.

  On the other hand, the hub bolt 36 is formed with a press-fit fixing serration portion (hereinafter abbreviated as a serration portion) 362 in the circumferential direction on the outer peripheral surface of the shaft base end 361 side. The hub bolt 36 press-fits the serration portion 362 into the hub bolt insertion hole 33a, and the hub bolt head portion 360 formed on the base end 361 side is connected to the peripheral portion 330b of the hub bolt insertion hole 33a on the vehicle inner side of the hub flange 33. It is attached in the form of abutting against. As for the steel material which comprises this hub bolt 36, the Vickers hardness of the part containing the serration part 362 is made into Hv400 or more and Hv500 or less.

  Further, the hub flange 33 is formed by expanding the peripheral edge portion 331c of the hub bolt insertion hole 33a to the vehicle outer side main surface 33c as an outer side taper portion. The vehicle outer side edge 362a of the serration portion 362 is positioned to be retracted to the vehicle inner side with respect to the vehicle inner side edge 332c of the outer side taper portion 331c. Moreover, the opening peripheral part 331b to the vehicle inner side main surface 33b of the bolt insertion hole 33a is formed to have an enlarged diameter as an inner side tapered part. The inner-side taper portion 331b has an axial formation width A that is greater than the axial-direction formation width B of the outer-side taper portion 331c. In this embodiment, the inner side taper portion 331b is formed with an axial direction formation width A of 4 mm, and the outer side taper portion 331c is formed with an axial direction formation width B of 2 mm. In addition, if the retracted length of the outer side taper portion of the serration portion 362 from the inner side edge of the outer taper portion to the inner side of the vehicle is at least 0.5 mm to 6 mm, burrs are generated. Can be reliably prevented.

  A hub bolt 36 is press-fitted into the hub bolt insertion hole 33 a of the hub flange 33. The brake disc rotor 7 and the tire wheel 6 are attached to the main surface on the vehicle outer side of the hub flange 33 in this order, and are attached by tightening a hub bolt 36 and a nut (not shown).

  The axle 10 is inserted into the shaft hole 32 of the hub wheel 3 so as to penetrate therethrough. The axle 10 is linked to a transmission shaft 15 that transmits output rotation of a differential device (not shown) via an axle body (constant velocity joint portion) 14 that forms a vehicle inner side end portion 14. A spline portion 11 (hereinafter referred to as a hub mounting portion 11) serving as a hub mounting portion is provided, and a screw portion 10b is formed on the vehicle outer side. A large-diameter portion 11d having an outer diameter larger than that of the spline portion 11 is formed with a step on the vehicle inner side, which is the rear side of the spline portion 10a, and the constant velocity joint 14 is further extended from the large-diameter portion 11d to the vehicle inner side. The outer ring 14a is formed so as to bulge outward in the radial direction. The constant velocity joint 14 includes an inner ring 14b, a ball (not shown), and a cage. A nut 16 that is a fastening member is attached to the threaded portion 10 b of the axle 10 on the vehicle outer side of the shaft hole 32.

  When the hub mounting portion 11 of the axle 10 is inserted into the shaft hole 32 of the hub unit 1, the vehicle inner side end surface 4 a of the inner ring 4 of the hub unit 1 and the vehicle body outer side end surface 14 c of the constant velocity joint 14 of the axle 10 come into contact with each other. . By tightening the nut 16 as a fastening member in contact with the nut seat surface 61 of the hub wheel 3, the vehicle body outer side end surface 14 c of the constant velocity joint 14 is pressed against the vehicle inner side end surface 4 a of the inner ring 4. By holding the pressure contact state (tightened state) by the nut 16, the axle 10 is coupled to the shaft hole 32 of the shaft portion 30 in an axially stationary manner.

  As mentioned above, although embodiment of this invention was described, these are only illustrations to the last, and this invention is not limited to these, A various change is possible unless it deviates from the meaning of a claim. .

Sectional drawing which shows 1st embodiment of the hub unit of this invention. Sectional drawing which shows 2nd embodiment of the hub unit of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hub unit 2 Outer ring 3 Hub wheel 4 Inner ring 5 Rolling element 10 Axle 11 Spline part (hub mounting part)
14 Axle body (constant velocity joint)
16 Nut (fastening member)
101 Stepped surface 102 Inclined surface 30 Shaft part 32 Shaft hole 33 Hub flange (wheel mounting flange)
33a Bolt insertion hole 362 Serration part (Press-fit fixing serration part)
360 Hub bolt head (bolt head)
330b Bolt insertion hole peripheral edge portion of hub flange on vehicle inner side 33b Vehicle inner side main surface of hub flange 33c Vehicle outer side main surface of hub flange 332c Vehicle outer side edge of outer side taper portion 331b Inner side taper portion 331c Outer side Taper 36 Hub bolt (wheel mounting bolt)
361 Axis base end 362a Vehicle outer side end edge of serration part

Claims (3)

An outer ring that is used by being attached to the vehicle outer side end of the axle and is non-rotatably attached to the vehicle body side, a hub wheel that is concentrically arranged with the outer ring and has a wheel mounting flange formed in the circumferential direction, and the hub wheel A rolling element row comprising a plurality of rolling elements arranged in the circumferential direction between the inner ring or the hub wheel and the outer ring. Hub unit
A bolt insertion hole for press-fitting a wheel mounting bolt is formed in the axial direction in the wheel mounting flange, while the wheel mounting bolt is used for press-fitting and fixing to the outer peripheral surface of the base end side of the shaft portion. A serration portion is formed in the circumferential direction, and the bolt head formed on the base end side is inserted into the bolt insertion hole peripheral portion on the vehicle inner side while the press-fitting fixing serration portion is press-fitted into the bolt insertion hole. It is attached in the form of contact,
While the Rockwell C scale hardness of the part including the inner peripheral surface of the bolt insertion hole of the steel constituting the wheel mounting flange is adjusted to HRC18 or more and HRC28 or less, the press fitting of the steel constituting the wheel mounting bolt is performed. A Vickers hardness of a portion including the fixing serration portion is set to Hv400 or more and Hv500 or less, and an opening peripheral portion to the vehicle outer side main surface of the bolt insertion hole serving as a protruding side of the wheel mounting bolt is The outer side taper portion is enlarged in diameter, and the vehicle outer side edge of the press-fit fixing serration portion is positioned closer to the vehicle inner side than the vehicle inner side edge of the outer side taper portion. Hub unit characterized by that.   An opening peripheral edge portion of the bolt insertion hole to the vehicle inner side main surface is expanded in diameter by an inner side taper portion, and an axial direction forming width of the inner side taper portion is an axial width of the outer side taper portion. The hub unit according to claim 1, wherein the hub unit is set to be larger than the direction forming width.   The retracted length from the vehicle inner side end edge of the outer side taper portion of the vehicle outer side edge of the press-fitting serration portion to the vehicle inner side is set to 0.5 mm or more and 6 mm or less. Item 3. The hub unit according to Item 2.

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