JP2003130062A - Hub unit bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hub unit bearing which realizes creep prevention in a connecting face between a bearing and hub. SOLUTION: Uneven female serrations 71 and 73 are formed on inner faces of a first inner ring 21 and second inner ring 31 respectively. When both inner rings 21 and 31 are press-fitted into a hub 41, these female serrations 71 and 73 cut into a shaft portion 42 while the female serrations make the outer peripheral face of the shaft portion 42 plastically deformed. Thus, the inner rings 21 and 31 of the bearing 5 and hub 41 are firmly fixed each other via the female serrations 71 and 73, and no creep on the connecting face of both of them is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hub unit bearing, and more particularly to a technique for preventing creep at a fitting surface between a bearing and a hub.

[0002]

2. Description of the Related Art In an axle device for an automobile, Japanese Patent Laid-Open No.
No. 00-110840 (hereinafter referred to as prior art 1)
As described in JP-A-2000-185507 (hereinafter referred to as prior art 2) and the like, so-called first-generation hub unit bearings in which a double-row angular contact ball bearing or the like is incorporated in a hub have been conventionally used. There is. In the hub unit bearings of the prior arts 1 and 2, the outer ring of the double-row angular contact ball bearing is internally fitted and press-fitted into the knuckle arm that is a suspension element,
A pair of inner rings are fitted and press-fitted onto the hub. A female spline is formed on the hub axis, while a male spline formed on the drive shaft of the constant velocity joint element is inserted into this female spline, and the driving force from the engine is transmitted to the transmission, drive shaft, constant velocity It is transmitted to the hub (that is, the wheel) through the joint. The constant velocity joint element and the hub are fastened by a nut that is screwed into a male screw at the tip of the drive shaft, and at this time, the inner ring is pressed against the large diameter portion of the constant velocity joint element, and the double row angular contact ball bearing is A predetermined preload is applied.

[0003]

When the automobile is turning, a large moment load acts on the suspension device due to an input from the ground contact surface of the wheel. for that reason,
In the hub unit bearing, a force that causes the hub to incline with respect to the bearing (unequal load) is generated, and this irregular load becomes extremely large, especially in large vehicles with large axle loads, and the fit between the inner ring of the bearing and the hub Creep sometimes occurred at the meeting. Usually, the inner ring and the hub are press-fitted with a predetermined tightening allowance and then joined and integrated by a fastening means such as a screw or caulking. Further, in the hub unit bearings of the prior arts 1 and 2 described above, Although it is pressed against the constant velocity joint element, it was difficult to completely prevent the occurrence of creep. When creep occurs, the fitting surfaces of the inner ring and the hub are damaged and abnormal heat is generated, and abrasion powder, which is a foreign substance, is generated. Further, in the hub unit bearing for the drive axle, there is a problem that the inner ring and the constant velocity joint element also slip, and the constant velocity joint element is worn. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hub unit bearing that realizes prevention of creep on the fitting surface between the bearing and the hub.

[0004]

Therefore, in order to solve the above-mentioned problems, in the invention of claim 1, the suspension element is fixed to the suspension element,
An outer ring having first and second outer raceway surfaces on which rolling elements are rollingly contacted is formed on an inner peripheral side, a hub having a wheel mounting flange formed at an axially outer end, and a first inner ring formed on the hub. A first inner ring having a first inner raceway surface on the outer peripheral side that is fitted / held on the holding portion and faces the first outer raceway surface of the outer ring, and a second inner ring holding portion formed on the hub. Between a second inner ring, which is held and has a second inner raceway surface facing the second outer raceway surface of the outer race on the outer peripheral side, and a first outer raceway surface of the outer race and an inner raceway surface of the first inner race. The first rolling element row, which is provided with a large number of rolling elements and cages, is provided between the second outer raceway surface of the outer ring and the inner raceway surface of the second inner ring. A hub unit bearing provided with a second rolling element row including rolling elements and a cage, wherein at least the first inner ring and the first inner ring holding portion are provided. On one side, a fitting means is provided on the fitting surface for preventing relative rotation of the two, and at least one of the second inner ring and the second inner ring holding portion is fitted with the locking means. It is proposed that the surface is provided with locking means for preventing relative rotation of the both.

According to the second aspect of the present invention, the outer ring having the first and second outer raceway surfaces fixed to the suspension element and rollingly contacting the rolling elements is formed on the inner peripheral side, and the first outer raceway of the outer race. A first inner ring having a first inner raceway surface facing the surface on the outer peripheral side is formed on the outer peripheral side, and a wheel mounting flange is formed on the axially outer end, and a second inner ring holding member formed on this hub A second outer surface that is fitted and held by the outer ring and faces the second outer raceway surface of the outer ring.
A second inner ring having an inner raceway surface on the outer peripheral side and a first inner ring of the outer ring
Interposed between an outer raceway surface and an inner raceway surface of the first inner ring,
A first rolling element row including a large number of rolling elements and a cage, and a first rolling element row interposed between the second outer raceway surface of the outer ring and the inner raceway surface of the second inner ring, and the large number of rolling elements and holdings And a second row of rolling elements consisting of
It is proposed that at least one of the inner ring and the second inner ring holding portion is provided with a locking means for preventing relative rotation between the inner ring and the second inner ring holding portion.

According to the first and second aspects of the invention, the second inner ring and the second inner ring holding portion are prevented from rotating relative to each other by the locking means, and the creeping at the fitting surface of both is prevented.

The invention of claim 3 proposes the hub unit bearing of claim 1 or 2, wherein the locking means is a convex portion or a concave portion.

The invention of claim 4 proposes the hub unit bearing of claim 3 in which the locking means is a serration or a spline.

According to the third and fourth aspects of the invention, for example, when the second inner ring is formed with female serrations, the second inner ring and the hub are fastened to each other so that the female serration fits into the second inner ring holding portion. A strong lock is achieved by biting while plastically deforming the mating surface. The holding portion is prevented from rotating relative to each other, and creep at the fitting surface between them is prevented.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The first embodiment is an application of the present invention to a first-generation hub unit bearing for a drive axle in an FF (front engine / front drive) type passenger vehicle. FIG. 1 is a hub unit bearing 1 according to the first embodiment.
FIG. In FIG. 1, the member indicated by reference numeral 3 is the outer ring of the double-row angular contact ball bearing 5, and the first and second members each having an arc-shaped cross section that is open outward in the radial direction on the inner peripheral side thereof.
Outer raceway surfaces 7 and 9 are formed. The outer ring 3 is internally fitted and press-fitted into a holding hole 13 formed in the knuckle arm 11 of the suspension device, and a locking flange 15 of the knuckle arm 11 is attached.
The movement in the axial direction is restricted by the annular retaining ring 17 and.

The first inner ring 2 is provided on the first outer raceway surface 7 side of the outer ring 3.
1 is disposed on the outer peripheral side of the first inner race 21, and a first inner raceway surface 23 having an arcuate cross-section that opens inward in the radial direction and that corresponds to the first outer raceway surface 7 of the outer race 3 is formed. There is. First
Between the outer raceway surface 7 and the first inner raceway surface 23, a first rolling element row 29 including a large number of steel balls and a cage is provided.
A second inner ring 31 is arranged on the second outer raceway surface 9 side of the outer race 3, and a radially inward direction corresponding to the second outer raceway surface 9 of the outer race 3 is arranged on the outer peripheral side of the second inner race 31. A second inner raceway surface 33 having an arcuate cross section opened to the inside is formed. Between the second outer raceway surface 9 and the second inner raceway surface 33, a second rolling element row 35 including a large number of steel balls and a cage is provided. In the figure,
Reference numeral 37 indicates a shaft seal interposed between the outer ring 3 and the first inner ring 21, and reference numeral 39 indicates a shaft seal interposed between the outer ring 3 and the second inner ring 31.

A shaft portion 42 of a hub 41, which is a first and second inner ring holding portion, is fitted and press-fitted on the inner peripheral surfaces of the first and second inner rings 21 and 31, and an outer end surface of the first inner ring 21 is attached. The shoulder 43 of the hub 41 is abutted and locked. The hub 41 has a flange 45 to which a wheel (not shown) is attached,
A through hole 49 in which a female serration 47 is formed is formed in the shaft core of the shaft portion 42. In the figure, the member indicated by reference numeral 51 is a hub bolt planted in the flange 45, and is used for fastening the wheel.

A drive shaft portion 55 extending from an outer housing 53 of a bar field joint, which is a constant velocity joint element, is fitted in the through hole 49 of the hub 41, and is engraved on the outer periphery of the drive shaft portion 55. The formed male serration 57 meshes with the female serration 47 of the through hole 49. The outer housing 53 has an outer end surface with the second inner ring 31.
While a large diameter portion 61 that contacts the end surface of the drive shaft 55 is formed, a male screw portion 65 with which the crown nut 63 is screwed is formed at the outer end of the drive shaft 55. And crown nut 6
By tightening 3 with a predetermined tightening torque, the hub 41 and the outer housing 53 are fastened and integrated,
At the same time, a proper preload is applied to the double-row angular contact ball bearing 5.

In the case of this embodiment, the female serrations 71, which are uneven, are formed on the inner peripheral surfaces of the first inner ring 21 and the second inner ring 31.
73 are formed respectively, and when both inner rings 21, 31 are press-fitted into the hub 41, these female serrations 71, 31
While 73 plastically deforms the outer peripheral surface of the shaft portion 42,
It will be difficult. Normally, the inner rings 21, 31 are SU
Made of bearing steel such as J2, its surface hardness is HR
It is about C60. Therefore, if the hub 41 is not subjected to a thermosetting treatment or the like and its surface hardness is relatively low, the plastic deformation by the female serrations 71 and 73 becomes easy.

The operation of the first embodiment will be described below. When the vehicle is running, the driving force from the engine is transmitted to the hub 41 via the transmission, the drive shaft, and the constant velocity joint. At the time of turning, the suspension device is generated due to the input from the ground contact surface of the wheel. A large moment load acts on. Therefore, in the hub unit bearing 1, the hub 4
An irregular load that tilts 1 with respect to the bearing 5 is generated, and this irregular load becomes extremely large particularly in a large vehicle or the like in which the axial load is large.

However, in this embodiment, the inner races 21, 31 of the bearing 5 and the hub 41 are connected to the female serration 7.
Since they are firmly fixed to each other via 1, 73, there is no risk of creep occurring on the fitting surfaces of the two. As a result, the inner races 21 and 31 and the hub 4 which have been a problem in the conventional device.
In addition to preventing damage to the fitting surface of No. 1 and abnormal heat generation, wear powder, which is a foreign substance, is no longer generated. Further, slippage does not occur between the second inner ring 31 and the outer housing 53, and problems such as wear of the outer housing 53 do not occur.

FIG. 2 is a half cutaway perspective view of the inner ring according to the second embodiment. Although the configuration of this embodiment is substantially the same as that of the above-described first embodiment, female serrations 71, 73 are formed only on the ends of the first and second inner rings 21, 31, respectively. Also in the second embodiment, the configuration and operation according to the invention are the same as those in the above-described first embodiment, and therefore the description thereof will be omitted.

FIG. 3 is a half-cut longitudinal sectional view showing a hub unit bearing according to the third embodiment. The third embodiment is one in which the present invention is applied to a second-generation hub unit bearing, and a double row tapered roller bearing is used as the bearing. In the case of the present embodiment, a flange 81 is formed on the outer circumference of the outer ring 3, and the flange 81 is fastened to the knuckle arm 11 by a bolt 83. In addition, the first and second rolling element rows 2
9 and 35 are composed of a large number of tapered rollers and a cage, and are provided with the first and second outer raceway surfaces 7 and 9 and the first and second inner raceway surfaces 2.
3 and 33 also have tapered surfaces corresponding to this. The second inner ring 31 is locked by the caulking portion 85 formed at the inner end of the hub 13. Also in the third embodiment, the female serrations 7 are formed on the inner peripheral surfaces of the inner rings 21 and 31.
1, 73 are formed, and these female serrations 7
The effect of the bites 1 and 73 biting into the shaft portion 42 of the hub 41 is the same as in the above-described first embodiment. Since a hub unit bearing having a double row tapered roller bearing is often used in heavy vehicles such as trucks, the demand for preventing the occurrence of creep is more serious than that of the hub unit bearing of the first embodiment.

FIG. 4 is a vertical sectional view showing a hub unit bearing according to the fourth embodiment. The fourth embodiment is one in which the present invention is applied to a third-generation hub unit bearing, and the flange 81 of the outer ring 3 has a bolt 83 as in the second embodiment.
Is fastened to the knuckle arm 11 by the first inner ring 2
1 is integrated with the hub 13. Also in the fourth embodiment, the female serration 73 is formed on the inner peripheral surface of the second inner ring 31, and the action of the female serration 73 biting into the shaft portion 42 of the hub 41 is the same as that of the first embodiment. It is the same.

The description of the specific embodiment is finished above.
Aspects of the present invention are not limited to the above embodiment.
For example, although each of the above-described embodiments applies the present invention to the hub unit bearing for the drive axle, it may be applied to the hub unit bearing for the driven axle. Further, in the above embodiment, the female serration is formed on the inner ring side of the bearing, but male serration may be formed on the shaft side of the hub. In this case, S53C is used as the inner ring material.
It is desirable to use a relatively soft steel such as, and to induction-harden only the raceway surface. Further, as the unevenness, it is possible to adopt a spline or the like other than the serration, or may be formed on both the shaft portion and the inner ring of the hub. Further, a groove may be formed in both the shaft portion of the hub and the inner ring, and locking may be performed by a parallel key or the like. Further, as the constant velocity joint, various things such as a tripod joint and a double cardan joint can be adopted in addition to the bar field joint. In addition, the specific configurations of the hub unit bearing and the suspension device are not limited to the examples in the above-described embodiment, and may be appropriately changed without departing from the gist of the present invention.

[0021]

As described above, according to the hub unit bearing of the present invention, at least one of the inner ring and the inner ring holding portion of the hub has a fitting surface for preventing relative rotation between the two. Since the locking means is formed, creep does not occur on the fitting surface between the inner ring and the inner ring holding part of the hub, damage to the part is prevented and abnormal heat generation is prevented. It is not generated and the life of the device is improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a hub unit bearing according to a first embodiment of the present invention.

FIG. 2 is a half-cut perspective sectional view of a bearing inner ring according to a second embodiment.

FIG. 3 is a half-cut longitudinal sectional view showing a hub unit bearing according to a third embodiment of the present invention.

FIG. 4 is a half-cut longitudinal sectional view showing a hub unit bearing according to a fourth embodiment of the present invention.

[Explanation of symbols] 1 ... Hub unit bearing 3 ... Outer ring 5 Bearing 21 ... First inner ring 29 ... First row of rolling elements 31 ... Second inner ring 35 ... Second row of rolling elements 41 ... Hub 42 ... Shaft 49 ... Through hole 47 ... Female serration 53 Outer housing (constant velocity joint element) 55: Drive shaft 57 ... Male Serration 61 ... Large diameter part 71, 73 ... Female serration 85 ... Crimping part

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) F16C 35/063 F16C 35/063

Claims (4)

[Claims] 1. An outer ring fixed to a suspension element and having first and second outer raceway surfaces on which rolling elements are rollingly contacted formed on the inner peripheral side, and a hub having a wheel mounting flange formed on the outer end in the axial direction. And a first inner ring having a first inner raceway surface on the outer peripheral side, which is fitted and held by a first inner raceway holding portion formed on the hub and faces the first outer raceway surface of the outer race, and the first inner race formed on the hub. A second inner race having a second inner raceway on the outer peripheral side that is fitted and held by the second inner race holding part and faces the second outer raceway of the outer race; a first outer raceway of the outer race; The first inner ring which is interposed between the inner raceway surface of the first inner ring and includes a large number of rolling elements and a cage.
A second rolling element row, which is interposed between the second outer raceway surface of the outer ring and the inner raceway surface of the second inner ring and which includes a large number of rolling elements and a cage.
A hub unit bearing including a rolling element row, wherein at least one of the first inner ring and the first inner ring holding portion has a fitting surface on which engagement is provided to prevent relative rotation between the two. And at least one of the second inner ring and the second inner ring holding portion is formed with locking means for preventing relative rotation of the second inner ring and the second inner ring holding portion. A characteristic hub unit bearing. 2. An outer ring fixed to a suspension element and having first and second outer raceway surfaces rollingly contacted by a rolling element on the inner peripheral side, and a first inner race facing the first outer raceway surface of the outer race. A first inner ring having a raceway surface on the outer peripheral side is formed on the outer peripheral side, and a wheel mounting flange is formed on the outer end in the axial direction, and a second inner ring holding portion formed on this hub is externally fitted and held. A second inner ring having a second inner raceway surface facing the second outer raceway surface of the outer race on the outer peripheral side, and an intermediate ring between the first outer raceway surface of the outer race and the inner raceway surface of the first inner race. First, consisting of a large number of rolling elements and cages
A second rolling element row, which is interposed between the second outer raceway surface of the outer ring and the inner raceway surface of the second inner ring and which includes a large number of rolling elements and a cage.
A hub unit bearing including a rolling element row, wherein at least one of the second inner ring and the second inner ring holding portion has a fitting surface on which engagement is provided to prevent relative rotation of the two. Hub unit bearing characterized in that means are formed. 3. The hub unit bearing according to claim 1, wherein the locking means is a convex portion or a concave portion. 4. The hub unit bearing according to claim 3, wherein the locking means is a serration or a spline.