JP7172407B2 - Rolling bearing unit for wheel support - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing unit for wheel support used to rotatably support a wheel of an automobile with respect to a suspension system.

It is conventionally known to use double-row tapered roller bearings having double-row tapered rollers as rolling elements in rolling bearing units for supporting wheels of relatively heavy automobiles such as small trucks and large passenger cars (for example, , see Patent Document 1).

FIG. 4(a) shows a bearing unit described in FIG. 3 of Patent Document 1, in which an inner ring 101 having an inboard side inner ring raceway 101a is fitted to a small diameter stepped portion 103 of a hub ring 102 by press fitting. In addition, the double-row stepped portion 103 is fixed in the axial direction by a crimp portion 104 formed by plastically deforming the inboard side end portion 103a (see FIG. 4B) of the small-diameter step portion 103 radially outward. 1 shows a tapered roller bearing type rolling bearing unit for wheel support.

The press-fitting of the inner ring 101 into the small-diameter stepped portion 103 constituting the hub wheel 102 and the formation of the caulked portion 104 cause expansion on the inner diameter surface side of the inner ring 101, but the large flange portion 105 functions to suppress the expansion. Therefore, the large flange portion 105 inclines (falls down) in a direction in which the large flange angle α decreases. As a result, the contact position between the head portion 106a of the tapered roller 106, which is a partially spherical surface, and the large flange portion 105, which is a partially conical surface, moves to the outer diameter side of the large flange portion 105, and the head of the tapered roller 106 at the contact position moves. The sliding wear speed between the portion 106a and the large collar surface 105a increases, and the torque and heat generation increase accordingly, which makes seizure more likely to occur. The large flange angle α represents the angle formed between the large flange surface 105a of the large flange portion 105 with which the tapered roller 106 contacts and the axial direction.

As a solution to the above problem, in Patent Document 1, the large flange portion 105 of the inner ring 101 is extended toward the inboard side to ensure the rigidity of the large flange portion 105, and the outer peripheral surface of the large flange portion 105 is provided with an inboard A small-diameter portion 107 is formed on the side with a predetermined step δ. As a result, even if the inner ring 101 is expanded radially outward during crimping, the hoop stress generated on the outer peripheral surface is reduced, and the large flange portion 105 is prevented from collapsing. .

Japanese Unexamined Patent Application Publication No. 2008-2608

By the way, in the wheel-supporting rolling bearing unit having such a configuration, the axial dimension of the inner ring 101 is increased to ensure the rigidity of the large flange portion. Accordingly, there is a problem that the mass increases. Further, the configuration in which the large flange portion 105 of the inner ring 101 is extended toward the inboard side has the effect of suppressing the expansion of the inner diameter surface side of the inner ring 101 after crimping, but the expansion to the small diameter stepped portion 103 of the hub wheel 102 is prevented. There is no effect of suppressing the expansion of the inner diameter surface due to the press-fitting of the inner ring 101 .

In view of the circumstances as described above, the present invention provides hoop stress generated on the outer peripheral surface of the large flange portion when the inner ring is press-fitted into the hub ring or when the inner ring is positioned by the caulking portion formed on the hub ring. It is an object of the present invention to provide a wheel-supporting rolling bearing unit capable of reducing the friction and preventing the large flange from collapsing.

The above objects of the present invention are achieved by the following configurations.
(1) an outer ring having a double-row outer ring raceway on its inner peripheral surface;
a hub having a double-row inner ring raceway on the outer peripheral surface and a rotation-side flange for supporting and fixing the wheel on the outboard side;
a plurality of tapered rollers rotatably provided between the double-row outer ring raceway and the double-row inner ring raceway;
with
The hub is positioned on the hub ring by means of a hub ring having the rotation-side flange and a crimping portion formed on the inboard side end portion of the hub ring. and at least one inner ring formed by
In the inner ring having the inner ring raceway on the inboard side, a plurality of notches extending in the axial direction from the axial inner end surface on the side of the large flange are intermittently formed in the circumferential direction.
Rolling bearing unit for wheel support.
(2) The wheel-supporting rolling bearing unit according to (1), wherein each of the cutouts is formed over the axial inner end surface of the large flange portion and the outer peripheral surface of the large flange portion.
(3) The wheel-supporting rolling bearing unit according to (1), wherein the hub includes a pair of inner rings having a common shape.
(4) The axial inner end face of the inner ring on the side of the large flange portion is arranged in the axial direction at a position substantially equal to the axial inner end face of the outer ring, or on the outboard side of the axial inner end face. A wheel-supporting rolling bearing unit according to any one of (1) to (3).

According to the wheel-supporting rolling bearing unit of the present invention having the configuration described above, the plurality of notches formed intermittently in the inner ring in the circumferential direction allow the outer peripheral surface of the large flange portion to be press-fitted or caulked. The generated hoop stress can be reduced, the rigidity of the large collar portion can be secured, and collapse of the large collar portion can be prevented.

1 is a cross-sectional view of a rolling bearing unit for supporting a wheel according to a first embodiment of the present invention; FIG. FIG. 7 is a cross-sectional view of a wheel-supporting rolling bearing unit according to a second embodiment of the present invention; FIG. 10 is a cross-sectional view of a wheel-supporting rolling bearing unit according to a third embodiment of the present invention; (a) is an enlarged view of a main part of a conventional rolling bearing unit for supporting a wheel, and (b) is an enlarged view of the main part before crimping of (a).

A wheel-supporting rolling bearing unit according to each embodiment of the present invention will be described in detail with reference to FIGS. In the entirety of this specification and the scope of claims, "outside" with respect to the axial direction refers to the left side in FIGS. The right side in FIGS. 1 to 3, which is the center side in the width direction, is referred to as "inside" with respect to the axial direction.

(First embodiment)
The wheel supporting rolling bearing unit of the first embodiment is for a driven wheel and includes an outer ring 1, a hub 2, a plurality of tapered rollers 3, 3, a plurality of stud bolts 4, a seal ring 5, an end a cap 6;

The outer ring 1 has a stationary flange 7 on its outer peripheral surface and double-row (two-row) outer ring raceways 8a and 8b on its inner peripheral surface. In use, the outer ring 1 does not rotate while supported by the suspension by fixing the stationary flange 7 to the knuckle of the suspension.

The hub 2 is constructed by joining a hub ring 9 and an inner ring 10, and is arranged coaxially (concentrically) with the outer ring 1 on the inner diameter side of the outer ring 1. As shown in FIG.

The hub wheel 9 is provided with a rotating member for braking such as a wheel (driven wheel) and a disc rotor extending radially outward from a portion protruding axially outward from an axially outer (outboard side) opening of the outer ring 1. A ring-shaped rotation-side flange 11 is provided for supporting and fixing. Specifically, the rotation-side flange 11 is provided with a plurality of insertion holes 22 , and the stud bolts 4 are serration-fitted into the respective insertion holes 22 .

An axially outer row of inner ring raceways 12 a is provided on the outer peripheral surface of the hub wheel 9 at a portion facing the axially outer row of outer ring raceways 8 a provided on the inner peripheral surface of the outer ring 1 . A small-diameter stepped portion 13 is formed at an axially inner end portion of the outer peripheral surface of the hub wheel 9 that faces the outer ring raceway 8b in the axially inner (inboard side) row provided on the inner peripheral surface of the outer ring 1. is provided.

The outer peripheral surface of the inner ring 10 is provided with an axially inner row of inner ring raceways 12b. The inner ring 10 is externally fitted and fixed to the small-diameter stepped portion 13 of the hub wheel 9 by press-fitting with an interference allowance. It is positioned and fixed to the hub wheel 9 by pressing the axial inner end face 14a on the side.
Note that the axial inner end surface 14a on the side of the large flange portion 14 is located at a position substantially equal to the axial inner end surface 1a of the outer ring 1 in the axial direction or outboard from the axial inner end surface 1a, as in the present embodiment. From the viewpoint of reducing the weight of the wheel-supporting rolling bearing unit, it is preferable to arrange it on the side.

A plurality of tapered rollers 3, 3 are provided in the cage between the outer ring raceway 8a and the inner ring raceway 12a of the axially outer row and between the outer ring raceway 8b and the inner ring raceway 12b of the axially inner row. It is rotatably provided while being held by 24 , 24 .

A seal ring 5 is provided with a plurality of tapered rollers 3, 3 which are supported and fixed to the axial outer end portion of the outer ring 1 and which are present between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the hub 2. It closes the axially outer end opening of the internal space 28 .
On the other hand, the end cap 6 is configured in a bottomed cylindrical shape, and closes the axial inner end opening of the internal space 28 in a state of being attached to the axially inner end portion of the inner peripheral surface of the outer ring 1 .

In the inner ring 10 having the inner ring raceway 12b in the axially inner row, a plurality of notches 15 extending in the axial direction from the axially inner end surface 14a on the side of the large collar portion 14 are intermittently spaced at equal intervals in the circumferential direction. formed in In particular, in the present embodiment, each notch 15 is intermittently formed by forging over the axial inner end surface 14a on the large collar portion 14 side and the outer peripheral surface 14b of the large collar portion 14 . Therefore, the inside of the notch 15 (the bottom surface of the recessed portion and both circumferential side surfaces) is a forged surface by forging. The bottom surface of the notch 15 is formed to have an arcuate cross-section (curved surface) from the radially intermediate portion of the axially inner side surface 14a toward the axially intermediate portion of the outer peripheral surface 14b. The bottom surface of the notch 15 can also be formed to have a linear cross section.
Each notch 15 is formed on the outer diameter side of the portion of the axial inner end surface 14a on the side of the large collar portion 14 with which the caulking portion 23 abuts. As a result, radially extending ribs 16 are formed between the notches 15 adjacent in the circumferential direction.

In the case of the wheel-supporting rolling bearing of this embodiment, the inner ring 10 is press-fitted onto the outer peripheral surface of the small-diameter stepped portion 13 of the hub wheel 9, or the axial inner end surface 14a of the large flange portion 14 is crimped. As a result, the inner diameter side portion of the inner ring 10 is expanded radially outward, and a hoop stress is generated in the large flange portion 14 to prevent the diameter expansion of the large flange portion 14 . However, due to the plurality of notches 15 provided in the axial inner end surface 14a of the inner ring 10 on the side of the large flange 14, generation of hoop stress on the outer peripheral surface 14b of the large flange 14 is suppressed. can be prevented from collapsing. In addition, the plurality of radially extending ribs 16 prevent a large decrease in rigidity of the large flange portion 14 without increasing the axial dimension of the inner ring 10 (or the large flange portion 14). can be prevented from collapsing. Therefore, seizure at the contact position between the head portion of the tapered roller 3 and the large flange surface 14c of the large flange portion 14 can be suppressed.

In addition, since the notch 15 is formed in an open state over the axial inner end surface 14a on the side of the large collar portion 14 and the outer peripheral surface 14b of the large collar portion 14, forging can be easily performed.
Furthermore, since the notch 15 is formed when the inner ring 10 is forged, there is no need to add a new processing step and it can be formed without increasing costs.

(Second embodiment)
Next, a wheel supporting rolling bearing unit of a second embodiment will be described with reference to FIG. The same or equivalent parts as those of the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted or simplified.

The wheel-supporting rolling bearing unit of this embodiment is for a driving wheel, and includes an outer ring 1, a hub 2a, a plurality of tapered rollers 3, 3, a plurality of stud bolts 4, and a seal ring 5. .

As in the first embodiment, the hub 2a includes a hub wheel 9a and an inner ring 10a, but a spline hole 17 is formed through the hub wheel 9a in the central portion thereof in the axial direction. A spline shaft (not shown) connected to a constant velocity joint is engaged with the spline hole 17 when the wheel supporting rolling bearing unit is assembled to the vehicle body, and is fixed to the hub 2a by screwing a nut.

The axially outer end opening of the internal space 28 is closed by the seal ring 5 as in the first embodiment, while the axially inner end opening of the internal space 28 is a combined seal ring consisting of a seal ring 18a and a slinger 18b. blocked by 18. The seal ring 18a is fixed to the inner peripheral surface of the outer ring 1, and the slinger 18b is formed to have an L-shaped cross section and is externally fitted and fixed to the outer peripheral surface 14b of the large flange portion 14 of the inner ring 10a. An encoder 19 for detecting the rotation speed of the wheel is attached to the inner side surface in the axial direction of the slinger 18b so as to face a rotation detection sensor (not shown).

The plurality of notches 15a of the present embodiment are opened in the axial inner end surface 14a on the large collar portion 14 side and extend axially from the axial inner end surface 14a. not opened. Each notch 15a is intermittently formed by forging from the axial inner end surface 14a on the side of the large collar portion 14, and radially extending ribs 16a are provided between the notches 15a adjacent in the circumferential direction. is formed. The notch 15a is formed to have a U-shaped cross section, but it can also be formed to have a polygonal (triangular or rectangular) cross section.

Therefore, also in this embodiment, a plurality of notches 15a are provided in the axial inner end surface 14a of the inner ring 10a on the side of the large collar portion 14. As shown in FIG. As a result, even if the inner ring 10a is press-fitted onto the outer peripheral surface of the small-diameter stepped portion 13 of the hub wheel 9 or crimped by the crimping portion 23, the inner ring 10a is expanded radially outward. The hoop stress generated on the outer peripheral surface 14b of the collar portion 14 can be reduced, and the large collar portion 14 can be prevented from collapsing. In addition, the plurality of radially extending ribs 16a suppress a large decrease in rigidity of the large flange portion 14 without increasing the axial dimension of the inner ring 10a, and further prevent the large flange portion 14 from collapsing. . Therefore, seizure at the contact position between the head portion of the tapered roller 3 and the large flange surface 14c of the large flange portion 14 can be suppressed.

Since the notch 15a is formed as a depression in the axial inner end surface 14a on the side of the large collar portion 14, forging can be easily performed. Therefore, since the notch 15a is formed when the inner ring 10a is forged, there is no need to add a new processing step, and the cutout 15a can be formed without increasing the cost.
In addition, since each notch 15a is not open on the outer peripheral surface of the large flange portion 14, the slinger 18b can be stably fitted and fixed to the outer peripheral surface of the large flange portion 14. As shown in FIG.

(Third embodiment)
Next, a rolling bearing unit for wheel support according to a third embodiment will be described with reference to FIG. The same or equivalent parts as those in the first or second embodiment are denoted by the same reference numerals, and descriptions thereof are omitted or simplified.

The wheel-supporting rolling bearing unit of this embodiment is for a driven wheel, and the inner ring raceways 12a, 12b of the axially outer row and the axially inner row are both composed of inner rings 10a1, 10a2. However, it differs from that of the first embodiment in that it is constituted by the inner ring 10a having the notch 15a of the second embodiment. Therefore, the pair of inner rings 10a1 and 10a2 have a shape common to each other. The notch 15a is provided at a position on the larger diameter side than the portion with which the crimping portion 23 abuts and on the smaller diameter side than the ridge of the inward stepped surface at the base of the rotation-side flange 11 .

Therefore, the small-diameter stepped portion 13 of the hub wheel 9b is formed from the vicinity of the rotation-side flange 11. As shown in FIG. The pair of inner rings 10a1 and 10a2 are fitted onto the outer peripheral surface of the small-diameter stepped portion 13 by press-fitting in a state in which the small flange portions are in contact with each other (the large flange portions 14 are provided on opposite sides in the axial direction). and is crimped by the crimping portion 23 to be positioned and fixed to the hub wheel 9b.

An axial outer end opening of the internal space 28 is closed by a combined seal ring 21 consisting of a seal ring 21a and a slinger 21b. The seal ring 21a is fixed to the inner peripheral surface of the outer ring 1, and the slinger 21b is formed to have an L-shaped cross section and is externally fitted and fixed to the outer peripheral surface 14b of the large flange portion 14 of the inner ring 10a1 on the outboard side.
On the other hand, the axially inner end opening of the internal space 28 is closed by the end cap 6 as in the first embodiment.
A slinger 20 having an L-shaped cross section is fitted and fixed to the outer peripheral surface 14b of the large collar portion 14 of the inboard side inner ring 10a2, and an encoder 19 is attached to the axial inner surface of the slinger 20. In this case, since the magnetic flux signal of the encoder 19 is sensed through the end cap 6, the end cap 6 is made of non-magnetic material.

As described above, according to the present embodiment, the inboard side inner ring 10a2 is configured by the inner ring 10a having the plurality of cutouts 15a as in the second embodiment, so that similar effects can be achieved. .
Furthermore, in this embodiment, the hub 2b includes the pair of inner rings 10a1 and 10a2 having the same shape, so that the pair of inner rings 10a1 and 10a2 are made of the same parts, and the number of parts can be reduced.
The configuration in which the double-row inner ring raceways 12a and 12b are respectively formed by a pair of inner rings 10a1 and 10a2 can also be applied to the rolling bearing unit for wheel support on the driving wheel side shown in FIG.

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified and improved as appropriate.
For example, the wheel-supporting rolling bearing units of the first and second embodiments may be so-called PCD type double-row tapered roller bearings in which the pitch circle diameters of the double-row tapered rollers are different from each other.

Reference Signs List 1 outer ring 2, 2a, 2b hub 3 tapered roller 4 stud bolt 5 seal ring 6 cap 7 stationary side flange 8a, 8b outer ring raceway 9, 9a, 9b hub ring 10, 10a, 10a1, 10a2 inner ring 11 rotating side flange 12a, 12b Inner ring raceway 13 Small diameter stepped portion 14 Large flange portion 15, 15a Notch 23 Crimp portion 24 Cage 28 Internal space

Claims (4)

an outer ring having a double-row outer ring raceway on its inner peripheral surface;
a hub having a double-row inner ring raceway on the outer peripheral surface and a rotation-side flange for supporting and fixing the wheel on the outboard side;
a plurality of tapered rollers rotatably provided between the double-row outer ring raceway and the double-row inner ring raceway;
with
The hub is positioned on the hub ring by means of a hub ring having the rotation-side flange and a crimping portion formed on the inboard side end portion of the hub ring. and at least one inner ring formed by
The inner ring having the inner ring raceway on the inboard side is intermittently formed with a plurality of notches extending in the axial direction from the axial inner end surface on the side of the large flange ,
The axial inner end face of the inner ring on the side of the large flange portion is arranged in the axial direction at a position substantially equal to the axial inner end face of the outer ring or on the outboard side of the axial inner end face,
An end cap is attached to the axially inner end of the inner peripheral surface of the outer ring,
A wheel-supporting rolling bearing unit in which a slinger is externally fitted and fixed to the outer peripheral surface of the large flange portion of the inner ring so as to axially overlap the end cap. Each notch is provided at a position on the larger diameter side than the portion with which the crimping portion abuts and on the smaller diameter side than the ridge of the inward step surface at the base of the rotation side flange.
A rolling bearing unit for supporting a wheel according to claim 1. 2. The rolling bearing unit for supporting a wheel according to claim 1, wherein each of said cutouts is formed over an axially inner end surface of said large flange portion and an outer peripheral surface of said large flange portion. 2. The rolling bearing unit for supporting a wheel according to claim 1, wherein said hub comprises a pair of said inner rings having a shape common to each other.

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