JP2000310228A - Rolling bearing unit for supporting wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To retain sufficient durability without increasing the volume of a caulk section by supporting and fixing an inner ring with the caulk section at the end section of a shaft member, and securing the length of the end section of the inner ring, so that the load from a rolling element is not applied to the caulk section in a first inner ring race. SOLUTION: The axial size of a first large flange 22a formed at the inner end section of a first inner ring 13a of a unit 10a is increased, and a caulk section 25 is formed on the inner diameter side of the inner half section of the large flange 22a. With the unit 10a assembled to an automobile, an inward radial load in the diameter direction is applied to an inner ring race 18 on the outer periphery of the inner ring 13a from a plurality of conical rollers 4 at a portion between two chain lines α, but the caulk section 25 is located off the applied portion of the radial load, little stress is exerted on the caulk section 25, and the caulk section 25 is hardly loosened. Assembling work is simplified, manufacturing cost is reduced, and sufficient durability can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The rolling bearing unit for supporting wheels according to the present invention is used to rotatably support relatively heavy wheels for automobiles such as small trucks and large passenger cars with respect to a suspension system.

[0002]

2. Description of the Related Art The wheels of an automobile are rotatably supported by a rolling bearing unit on a suspension system. In addition, a double-row tapered roller bearing unit is used to support a heavy automobile wheel. FIG. 3 shows a double-row tapered roller bearing unit 1 conventionally widely used for supporting wheels. This double row tapered roller bearing unit 1
A pair of inner rings 3, 3 are rotatably supported by a plurality of tapered rollers 4, 4, respectively, on the inner diameter side of one outer ring 2. On the inner peripheral surface of the outer ring 2, double-row outer ring tracks 5, 5 each having a conical concave shape, and on the outer peripheral surface of each inner ring 3, each inner ring track 6, each having a conical convex shape, 6 are formed respectively. The tapered rollers 4, 4 are held between the outer raceways 5, 5 and the inner raceways 6, 6, respectively, while being held by the retainers 7, 7 so as to be freely rotatable. Further, between the inner peripheral surfaces of both ends of the outer ring 2 and the outer peripheral surfaces of the ends of the inner rings 3, 3,
A pair of seal rings 8 and 8 are attached to the space 9 where the tapered rollers 4 and 4 are installed to close the openings at both axial ends.

[0003] Double row tapered roller bearing unit 1 as described above
Therefore, in order to support the wheels with respect to the suspension, the outer ring 2 is internally fitted and supported in a support hole provided in the suspension, and
An axle that supports the wheels is inserted into each of the inner rings 3,3.
By the way, when the wheels are supported on the suspension device by the double row rolling bearing unit 1 as shown in FIG. 3, the number of working steps in the automobile assembly factory is large, and it is difficult to reduce the cost. For this reason, in order to support wheels of automobiles, such as light trucks and large passenger cars, which are relatively heavy, but need to consider mass productivity (assembly), wheel bearings combining more parts at the bearing factory are required. It is also considered to constitute a rolling bearing unit.

[0004]

DESCRIPTION OF THE PRESENT INVENTION FIG. 4 shows a rolling bearing unit 10 for supporting a wheel considered prior to the present invention in consideration of such points.
Is shown. This rolling bearing unit 10 for supporting wheels
A hub 12 and first and second inner rings 13 and 14 as shaft members, which are combined with each other to form an inner race member, and a plurality of cones. Rollers 4 and 4 are provided. Of these, the outer race 11 has first and second outer raceways 15, 16 each having a conical concave surface on the inner circumferential surface, and the outer race 11 on the outer circumferential surface for supporting and fixing the outer race 11 to a suspension device. Outward flange-shaped mounting portions 17 are respectively formed. The inclination directions of the first and second outer raceways 15, 16 are opposite to each other.

On the outer peripheral surfaces of the first and second inner races 13 and 14, first and second inner races 13 and 14 each have a conical convex curved surface.
The second inner ring raceways 18 and 19 are formed. The first,
The second inner rings 13 and 14 are inner half portions of the hub 12 (half portions that are closer to the center in the width direction when assembled to a vehicle,
It is externally fitted to the step 20 formed in the right half of FIG. 4). In this state, the inclination directions of the first and second inner raceways 18, 19 are opposite to each other. In addition, the outer end of the hub 12 (the end that is outward in the width direction when assembled to a vehicle, which is the left end in FIG. 4) has a portion protruding from the outer end opening of the outer race 11 on the outer peripheral surface. A flange 21 for supporting and fixing the wheel to the hub 12 is formed.

Further, the first and second outer raceways 15, 1
The plurality of tapered rollers 4, 4 are provided between the first and second inner ring raceways 18, 19, respectively, in such a manner that the tapered rollers 4, 4 are held by the retainers 7, 7 so as to freely roll. .
Also, between the inner peripheral surfaces of both ends of the outer ring 11 and the outer peripheral surfaces of the first and second large collars 22 and 23 formed on the opposite ends of the first and second inner rings 13 and 14, respectively. A sealing means such as a combination seal ring 8, 8 is provided to close the opening at both axial ends of the space 9 in which the tapered rollers 4, 4 are installed.

[0007] Of the first and second inner rings 13 and 14,
The second inner race 14 is fitted externally to the inner part (left part in FIG. 4) of the step portion 20 formed on the hub 12, and the first inner race 13 is fitted externally to the inner end. The cylindrical portion 24 formed at the inner end of the hub 12 (including a tapered shape or a polygonal or spline-shaped outer peripheral surface).
The inner end surface of the first inner ring 13 is suppressed by a caulking portion 25 formed by plastically deforming the first inner ring 13 in the diameter direction. In this state, the first and second inner rings 13 and 14
Is fixed to the hub 12 by being sandwiched from both sides in the axial direction by a step surface 26 formed at the inner end of the step portion 20 and the caulking portion 25.

The cross-sectional shape of the inner end surface of the caulked portion 25 is a compound curved surface having a large radius of curvature on the inner diameter side and a small radius of curvature on the outer diameter side. In order to form such a caulked portion 25, the inner peripheral surface of the cylindrical portion 24 before plastic deformation is
It has a conical concave surface whose diameter increases toward the inner end opening. Also, when the caulking portion 25 is subjected to plastic working, particularly at the end of the working, a force (compression stress) directed inward in the diametrical direction of the caulking portion 25 is applied to the caulking portion 2.
5, so as not to cause damage such as cracks. For this,
The plastic working of the caulked portion 25 is preferably performed by swing forging.

The hub 12 is integrally formed by forging a carbon steel material having a C (carbon) content of about 0.2 to 1.1% by weight. Then, an intermediate portion or a back portion of the step portion 20, a base portion of the flange 21, and the like,
The portions requiring strength are hardened and hardened by induction hardening or the like. However, the caulked portion 25 should be formed,
The above-mentioned cylindrical portion 24 is not subjected to a quenching process and is left as it is. In contrast, the first and second inner rings 1
Nos. 3 and 14 are made of high carbon chromium bearing steel such as SUJ2, and are hardened and hardened to the core. Or, the first,
The second inner rings 13 and 14 may be made of chrome steel, chrome molybdenum steel, or the like, and the surfaces may be hardened by carburizing and quenching.

[0010]

In the case of a rolling bearing unit 10 for supporting a wheel as shown in FIG. 4 which is a double row tapered roller bearing unit, the first inner ring is used in a state where a large radial load is applied. It is necessary to prevent the caulking portion 25 fixing the inner ring 13 from loosening due to the radial load received by the over a long period of time. For this purpose, it is conceivable to make the volume of the caulked portion 25 sufficiently large. However, in addition to the increase in weight, the processing time for forming the caulked portion 25 is lengthened, which causes an increase in cost. Not preferred.

That is, each inner roller 13 has a tapered roller 4,
A radial load is applied from the rolling surface of No. 4. This radial load is perpendicular to the contact portion between the rolling surfaces of the tapered rollers 4 and 4 and the first inner raceway 18, that is, in the direction perpendicular to the generatrix of the first inner raceway 18. It is applied diametrically inward over the entire width of the abutment. The range in which the radial load is applied in this manner corresponds to the two chain lines α and α shown in FIG.
It is the part between. In the case of the structure shown in FIG. 4, since a part of the caulked portion 25 exists between the two chain lines α and α, a force in the direction of loosening the caulked portion 25 is applied to the caulked portion 25. Join. For this reason, as described above, it is necessary to increase the volume of the caulking portion 25, which causes the above-described inconvenience. The rolling bearing unit for supporting a wheel of the present invention has been invented in view of such circumstances.

[0012]

The rolling bearing unit for supporting a wheel of the present invention has a conical concave curved surface on the inner peripheral surface, similarly to a conventionally known rolling bearing unit for supporting a wheel. An outer diameter raceway member forming the first and second outer raceways, and an inner raceway raceway member forming the first and second inner raceways each having a conical convex curved surface on the outer peripheral surface; A plurality of tapered rollers are provided between the first and second inner raceways and the first and second outer raceways so as to be freely rolled. Further, in the wheel supporting rolling bearing unit of the present invention, similarly to the above-described wheel supporting rolling bearing unit according to the preceding invention, the inner raceway ring member has the first inner raceway on its outer peripheral surface. And a shaft member having the second inner raceway formed directly or via another inner race on the outer peripheral surface thereof. And
The inner ring is externally fitted to the end of the shaft member, and the axial end surface thereof is suppressed by a caulking portion formed by plastically deforming a cylindrical portion formed at the end of the shaft member outward in the diametrical direction. As a result, it is supported and fixed to the shaft member. Further, in the case of the wheel supporting rolling bearing unit of the present invention, the load applied from each of the rolling elements to the first inner raceway is not applied to the caulked portion so that the load is applied axially from the first inner raceway. The length of the end of the inner ring, which is present around the caulked portion at the deviated position, is secured.

[0013]

In the case of the rolling bearing unit for supporting a wheel according to the present invention configured as described above, the swaged portion is not easily loosened without particularly increasing the volume of the swaged portion. Therefore, it is possible to realize an inexpensive rolling bearing unit for wheel support having sufficient durability.

[0014]

FIG. 1 shows a first embodiment of the present invention. A feature of the present invention is that the caulking portion 25 for fixing the first inner ring 13a to the hub 12 has a structure for preventing the caulking portion 25 from being loosened without particularly increasing the volume. is there. The structure and operation of the other parts are the same as those of the previous invention shown in FIG. 4 described above. Therefore, the same reference numerals are given to the same parts, and the duplicate description is omitted or simplified. The following description focuses on the characteristic portions of the above.

The wheel supporting rolling bearing unit 10 of the present embodiment.
In the case of a, the axial dimension of the first large collar 22a formed at the inner end (the right end in FIG. 1) of the first inner ring 13a is increased. The caulking portion 25 is provided with the first large collar 22a.
Are present on the inner diameter side of the inner half (the right half in FIG. 1). In a state where the wheel supporting rolling bearing unit 10a is assembled to an automobile, the first inner ring raceway 18 formed on the outer peripheral surface of the first inner ring 13a from a plurality of tapered rollers 4, 4 includes:
A radial load directed inward in the diameter direction is applied between the two chain lines α, α shown in FIG. As is clear from FIG. 1, the caulking portion 25 is entirely off the radial load acting portion. For this reason, the stress generated from the respective tapered rollers 4 and 4 in the caulked portion 25 is reduced, and the caulked portion 25 is hardly loosened.

According to FEM analysis by the present inventor, in the case of the structure shown in FIG. 4 described above, based on the radial load applied to the first inner raceway 18 from each of the double-row tapered rollers 4, 4, A maximum tensile stress of 93 kg / mm ² was generated in the caulked portion 25. On the other hand, in the case of the structure shown in FIG. 1, under the same conditions, the tensile stress generated in the caulked portion 25 could be suppressed to 51 kg / mm ² . As described above, the tensile stress generated in the caulked portion 25 can be suppressed to about 55% by only slightly increasing the axial dimension of the first large collar 22a formed at the inner end of the first inner ring 13a. The caulking portion 25 can be prevented from loosening without increasing the volume of the caulking 25 accordingly. In addition, a rolling bearing unit for supporting the wheel which has sufficient durability and is inexpensive can be realized.

Next, FIG. 2 shows a second embodiment of the present invention.
An example is shown. In the case of this example, a small diameter portion 27 is formed in the inner half portion (right half portion in FIG. 2) of the first large collar 22b formed at the inner end portion of the first inner ring 13b, and the caulking portion 25 is formed. The small diameter portion 27 is located on the inner diameter side. Accordingly, the outer diameter of the outer half portion (the left half portion in FIG. 1) of the first large collar 22b for externally fitting and supporting the combined seal ring 8 varies with the formation of the caulked portion 25. The amount is small and the change amount is stable (variation is small).
Therefore, if the combined seal ring 8 is manufactured in consideration of the amount of change in the outer diameter, a necessary interference is secured, and the sealing performance of the combined seal ring 8 can be sufficiently secured. The other configurations and operations are the same as those of the first example described above, and therefore, the same parts are denoted by the same reference numerals, and redundant description will be omitted.

[0018]

The rolling bearing unit for supporting a wheel according to the present invention is constructed and operates as described above, so that the assembling work in an automobile assembling factory can be simplified, and the production cost of the automobile can be reduced. A structure that can ensure high durability can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first example of an embodiment of the present invention.

FIG. 2 is a sectional view showing the second example.

FIG. 3 is a cross-sectional view showing one example of a conventional structure.

FIG. 4 is a sectional view showing an example of a structure considered prior to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Double row tapered roller bearing unit 2 Outer ring 3 Inner ring 4 Tapered roller 5 Outer ring track 6 Inner ring track 7 Cage 8 Combination seal ring 9 Space 10, 10a Rolling bearing unit for wheel support 11 Outer ring 12 Hub 13, 13a, 13b First Inner ring 14 Second inner ring 15 First outer ring track 16 Second outer ring track 17 Mounting portion 18 First inner ring track 19 Second inner ring track 20 Stepped portion 21 Flange 22, 22a, 22b First large collar 23 Second large collar 24 Cylindrical part 25 Caulking part 26 Step surface 27 Small diameter part

Claims (1)

[Claims] An outer raceway ring member having first and second outer raceways formed on the inner peripheral surface, each of which is a conical concave curved surface, and a second convex racesurface formed on the outer peripheral surface, each having a conical convex shape. First and second inner ring raceways, the inner raceway ring members, and a plurality of each of these first and second inner raceways and the first and second outer raceways are provided in a freely rolling manner. In the wheel supporting rolling bearing unit provided with a tapered roller, the inner raceway ring member includes an inner race having the first inner raceway formed on an outer peripheral surface thereof, and a direct or another inner race formed on the outer peripheral surface thereof. And a shaft member forming the second inner raceway through the inner race. The inner race is fitted around the end of the shaft member, and further, the cylindrical portion formed at the end of the shaft member is diametrically outwardly mounted. By pressing the end face in the axial direction by the caulking part formed by plastic deformation to A position that is axially displaced from the first inner raceway so that the load applied from each of the rolling elements to the first inner raceway is not applied to the caulked portion. A rolling bearing unit for supporting a wheel, characterized in that the length of the end of the inner ring existing around the caulked portion is secured.