JP2021143682A - Wheel bearing device - Google Patents

Abstract

To provide a wheel bearing device capable of improving strength of an inner member while suppressing increase of costs.SOLUTION: A wheel bearing device 1 includes an inner member 2 having a wheel mounting flange 22, an outer member 3, and a plurality of first and second rolling elements 41, 42. The first rolling element 41 at a side of the wheel mounting flange 22 is a conical roller having a large-diameter portion 411 at an axial one end portion, and a small-diameter portion 412 at the axial other end portion. The inner member 2 has an annular collar portion 23 with a collar surface 23a opposed to the large-diameter portion 411. An annular thinned portion 24 is formed between a first inner raceway surface 2a on which the first rolling element 41 is rolled and the collar surface 23a. An annular recessed portion 25 formed to be recessed toward a rotation axis O is formed between an apex portion 231 as an end portion at an outer diameter side of the collar portion 23 and the wheel mounting flange 22 in the axial direction, and a minimum diameter D1 of the recessed portion 25 is larger than a minimum diameter D2 of the thinned portion 24.SELECTED DRAWING: Figure 2

Description

The present invention relates to a wheel bearing device.

Conventionally, a wheel bearing device that supports a wheel with respect to a vehicle body has a cylindrical outer member attached to a knuckle of a suspension device, an inner member having a wheel mounting flange to which the wheel is attached, and an outer member. It is provided with a plurality of rolling elements arranged between the wheel and the inner member. Spherical rolling elements are often used for wheel bearing devices for small vehicles, but rolling elements are used for wheel bearing devices used for vehicles with a large body weight such as pickup trucks and vans, for example. As a result, a partial cone-shaped conical roller is often used.

In the inner member of the wheel bearing device in which such a conical roller is used, a tapered inner raceway surface on which the conical roller rolls and a brim surface facing the large diameter portion of the conical roller are formed by a grindstone. It is formed by grinding. At the corner between the inner raceway surface and the brim surface, a notch-shaped hollow portion extending in the circumferential direction is turned to allow the peripheral edge of the grindstone to escape during grinding and to avoid interference with the corner of the conical roller. Is formed by. However, when such a stiffened portion is formed, there is a problem that stress tends to be concentrated around the stiffened portion due to the bending load applied to the wheel mounting flange.

In the wheel bearing device described in Patent Document 1, the durability of the inner member is enhanced by subjecting the surface layer of the dull portion to a surface treatment by laser peening that applies compressive residual stress.

JP-A-2018-162817

As described in Patent Document 1, if the surface layer of the dull portion is surface-treated by laser peening to apply compressive residual stress, the durability of the inner member can be improved, but the man-hours for performing laser peening can be increased. It will increase and the cost will increase. In addition, for a large impact load generated when a wheel rides on a curb, for example, the effect of increasing the strength of the sewn part by applying compressive residual stress may not be fully exhibited. be.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wheel bearing device capable of increasing the strength of an inner member while suppressing an increase in cost.

In order to achieve the above object, the present invention comprises an inner member having a wheel mounting flange on which wheels are mounted, while the first and second inner raceway surfaces are formed in a double row so as to be arranged in the axial direction on the outer periphery. , A tubular outer member having first and second outer raceway surfaces facing the first and second inner raceway surfaces on the inner circumference, and the first inner raceway surface and the first one. The inner member includes a plurality of first rolling elements that roll on the outer raceway surface, and a plurality of second rolling elements that roll on the second inner raceway surface and the second outer raceway surface. Is a wheel bearing device that rotates about the rotation axis with respect to the outer member, and the first inner raceway surface is formed on the wheel mounting flange side with respect to the second inner raceway surface. The first rolling element is a conical roller having a large diameter portion at one end in the axial direction on the wheel mounting flange side and a small diameter portion at the other end in the axial direction, and the inner member is the conical roller. It has a brim surface facing the large-diameter portion and has an annular brim portion formed so as to project from the first inner ring raceway surface toward the outer member, and also has the first inner raceway. An annular slime portion is formed between the surface and the brim surface, and is formed so as to be recessed toward the rotation axis between the top portion, which is the outer diameter side end portion of the brim portion, and the wheel mounting flange. Provided is a wheel bearing device in which an annular recess is formed and the minimum diameter of the recess is larger than the minimum diameter of the recess.

According to the wheel bearing device according to the present invention, it is possible to increase the strength of the inner member while suppressing an increase in cost.

It is sectional drawing which shows the whole structure of the bearing device for a wheel which concerns on embodiment of this invention. (A) is an enlarged view showing the part A of FIG. 1 in an enlarged manner. (B) is an enlarged view showing a part of (a) in a further enlarged view. (A) is a partial cross-sectional view showing a part of a wheel bearing device according to a modified example. (B) is an enlarged view showing a part of (a) in a further enlarged view.

[Embodiment]
Embodiments of the present invention will be described with reference to FIGS. 1 and 2. It should be noted that the embodiments described below are shown as suitable specific examples for carrying out the present invention, and there are some parts that specifically exemplify various technically preferable technical matters. , The technical scope of the present invention is not limited to this specific aspect.

(Overall configuration of bearing device for wheels)
FIG. 1 is a cross-sectional view showing the entire configuration of the wheel bearing device according to the embodiment of the present invention in an axial cross section including the rotation axis O. In FIG. 1, a wheel bearing device mounted on a vehicle is shown together with its peripheral portion.

The wheel bearing device 1 rotatably supports the wheel 9 together with the brake rotor 8 with respect to the knuckle 7 constituting the vehicle suspension device. FIG. 1 shows a part of the wheel 91 of the wheel 9 and the brake rotor 8. Hereinafter, in the wheel bearing device 1, the side on which the wheel 9 is attached (left side in FIG. 1) is referred to as the vehicle outer side, and the opposite side (right side in FIG. 1) is referred to as the vehicle inner side. Further, the direction parallel to the rotation axis O is referred to as an axial direction.

The wheel bearing device 1 includes an inner member 2 composed of a hub 20 and an inner ring 200, a cylindrical outer member 3 fixed to a knuckle 7 which is a vehicle body side member, and an inner member 2 and an outer member 3. A plurality of first rolling elements 41 and a plurality of second rolling elements 42 arranged in a plurality of rows between the two, a first cage 51 holding the plurality of first rolling elements 41, and a plurality of first rolls. An annular space 10 between a second cage 52 that holds the rolling elements 42 of 2 and an inner member 2 and an outer member 3 that accommodate a plurality of first and second rolling elements 41 and 42. The first and second sealing devices 61 and 62 for sealing, the annular pulsar ring 11 that rotates integrally with the inner member 2, and the magnetic sensor attached to the outer member 3 so as to face the pulsar ring 11 in the radial direction. It has 12 and.

In FIG. 1, the wheel bearing device 1 is shown in an axial cross section including the rotation axis O. The annular space 10 is filled with grease (not shown). The inner member 2 rotates about the rotation axis O with respect to the outer member 3. The magnetic sensor 12 detects the strength of the magnetic field that changes as the pulsaring 11 rotates together with the inner member 2, and outputs a detection signal via the electric wire 121.

On the outer circumference of the inner member 2, the first and second inner raceway surfaces 2a and 2b are formed in a double row so as to be arranged in the axial direction. The first inner raceway surface 2a is formed on the vehicle outer side (wheel mounting flange 22 side, which will be described later) with respect to the second inner raceway surface 2b. The outer member 3 integrally has a cylindrical main body 31 and a vehicle body mounting flange 32 that is attached to the knuckle 7 by a plurality of knuckle bolts 71. On the inner circumference of the main body 31, a first outer raceway surface 3a facing the first inner raceway surface 2a in the radial direction and a second outer raceway surface 3b facing the second inner raceway surface 2b in the radial direction are formed. Has been done. The first rolling element 41 rolls on the first inner raceway surface 2a and the first outer raceway surface 3a. The second rolling element 42 rolls on the second inner raceway surface 2b and the second outer raceway surface 3b.

The hub 20 integrally has a body portion 21 arranged inside the outer member 3 and a wheel mounting flange 22 for fixing the wheels 9 and the brake rotor 8 so that they cannot rotate relative to each other. The body portion 21 is composed of a large diameter portion 211 and a small diameter portion 212 having different outer diameters, and the large diameter portion 211 is provided on the vehicle outer side of the small diameter portion 212. A first inner raceway surface 2a is formed on the outer peripheral surface of the large diameter portion 211, and a pulsaring 11 is attached to the outer peripheral surface. An inner ring 200 is fitted on the outer peripheral surface of the small diameter portion 212. A second inner raceway surface 2b is formed on the outer peripheral surface of the inner ring 200. In the present embodiment, the inner member 2 has one inner ring 200, but the inner member 2 has two inner rings, and one of the inner rings has a first inner ring. The inner raceway surface 2a may be formed, and the second inner raceway surface 2b may be formed on the other inner ring.

The wheel mounting flange 22 projects radially outward from the body portion 21 on the vehicle outer side of the outer member 3. The wheel mounting flange 22 is provided with a plurality of through holes 220 into which a plurality of hub bolts 13 are press-fitted. The hub bolt 13 has a head portion 131 and a shaft portion 132, and a hub nut 14 is screwed onto the tip end portion of the shaft portion 132. The wheel 91 of the wheel 9 is provided with an insertion hole 910 through which the shaft portion 132 of the hub bolt 13 is inserted, and the wheel 9 is fixed to the wheel mounting flange 22 by screwing the hub nut 14 into the hub bolt 13. There is.

The first sealing device 61 is attached to one end 311 on the vehicle outer side (wheel mounting flange 22 side) of the main body 31 of the outer member 3, and foreign matter from between the one end 311 and the wheel mounting flange 22. Intrusion is suppressed. The second sealing device 62 is composed of a disk-shaped cover member fitted to the other end 312 on the vehicle inner side of the main body 31 of the outer member 3, and closes the opening of the outer member 3 on the vehicle inner side. ing.

The first rolling element 41 and the second rolling element 42 are conical rollers made of, for example, bearing steel. The first rolling element 41 has a large diameter portion 411 at the end on the vehicle outer side and a small diameter portion 412 at the end on the vehicle inner side, and has a conical shape between the large diameter portion 411 and the small diameter portion 412. The rolling surface 41a of the above is formed. The second rolling element 42 has a large diameter portion 421 at the end on the vehicle inner side and a small diameter portion 422 at the end on the vehicle outer side, and has a conical shape between the large diameter portion 421 and the small diameter portion 422. The rolling surface 42a of the above is formed. The inner ring 200 is formed with a large brim 201 facing the large diameter portion 421 of the second rolling element 42 and a small brim 202 facing the small diameter portion 422 of the second rolling element 42.

When a load is applied to the inner member 2 from the wheel 9 attached to the wheel mounting flange 22, the load acts on the first rolling element 41 more than the second rolling element 42, and the hub of the inner member 2 Bending stress is generated at 20. Next, the configuration of the first rolling element 41 and its peripheral portion will be described in detail with reference to FIG.

FIG. 2A is an enlarged view showing the first rolling element 41 and its peripheral portion in FIG. 1 in an enlarged manner. FIG. 2B is an enlarged view showing a part of FIG. 2A in a further enlarged view. Hereinafter, the first rolling element 41 is referred to as a conical roller 41. Further, the first inner raceway surface 2a is simply referred to as an inner raceway surface 2a. In FIG. 2A, an extension line L extending the inner raceway surface 2a toward the wheel mounting flange 22 is shown by a alternate long and short dash line.

The inner member 2 has an annular flange formed between the wheel mounting flange 22 in the axial direction and the inner raceway surface 2a so as to project radially outward from the inner raceway surface 2a toward the outer member 3. It has a part 23. A brim surface 23a facing the large diameter portion 411 of the conical roller 41 is formed on the end surface of the brim portion 23 on the vehicle inner side. Labyrinth seal S, which is a minute gap having an effect of suppressing the invasion of foreign matter into the annular space 10 between the top portion 231 which is the end portion on the outer diameter side of the brim portion 23 and the main body 31 of the outer member 3. Is formed. The labyrinth seal S is formed in an annular shape between the outer peripheral surface 23b of the top portion 231 of the brim portion 23 and the inner peripheral surface 31a of the main body 31 of the outer member 3. The radial width of the labyrinth seal S is, for example, less than 1 mm.

The conical roller 41 is restricted from moving toward the outer side of the vehicle by the large diameter portion 411 coming into contact with the brim surface 23a. When the inner member 2 is rotated, the conical roller 41 rotates around the central axis of the large-diameter portion 411 while sliding on the brim surface 23a, and revolves around the inner raceway surface 2a.

At the corner between the inner raceway surface 2a and the brim surface 23a, the peripheral edge portion of the grindstone is released when grinding the inner raceway surface 2a and the brim surface 23a, and the peripheral edge portion of the large diameter portion 411 of the conical roller 41 is released. In order to avoid interference with the above, a slime portion 24 extending in the circumferential direction is formed. The slime portion 24 is formed in an annular shape by turning so as to project inward in the radial direction from the extension line L of the inner raceway surface 2a.

Further, the inner member 2 is formed with an annular recess 25 formed so as to be recessed in the radial direction toward the rotation axis O between the top portion 231 of the brim portion 23 and the wheel mounting flange 22. The recess 25 is formed by turning, for example, by a lathe forming the slime portion 24, before or after processing the slime portion 24, or at the same time.

Reference numerals 251 in FIGS. 2A and 2B indicate the deepest portion of the recess 25 in the depth direction (diameter direction). In the axial cross section of the inner member 2, the inner surface of the bottom portion of the recess 25 in the vicinity of the deepest portion 251 is formed in a curved shape without steps or corners. _{The minimum diameter D 1} of the recess 25, which is twice the distance between the deepest portion 251 of the recess 25 and the rotation axis O, is formed to be larger than _{the minimum diameter D 2} of the slime portion 24. In the present embodiment, the position of the deepest portion 251 of the recess 25 in the radial direction perpendicular to the rotation axis O is outside the extension line L of the inner raceway surface 2a and further outside the brim surface 23a. Is.

The first sealing device 61 has a metal member 611 fitted to one end 311 of the main body 31 of the outer member 3 and a sealing member 612 made of an elastic body such as rubber, and the metal member 611 and the sealing member. The 612 is integrally formed by, for example, vulcanization adhesion. The metal member 611 is press-fitted to the outer peripheral surface 311a of one end 311 of the main body 31 and is in contact with the axial end surface 311b of the one end 311.

The seal member 612 has a dust strip 612a that faces the wheel mounting flange 22 via a slight gap, a first seal lip 612b that is in sliding contact with the end surface 22a of the wheel mounting flange 22 on the vehicle inner side, and a recess 25. It has a second seal lip 612c that is in sliding contact with the inner surface. In the present embodiment, the second seal lip 612c is in sliding contact with the inner surface 25a on the top portion 231 side of the brim portion 23 from the deepest portion 251 of the recess 25.

In the wheel bearing device 1 configured as described above, the stress generated in the inner member 2 due to the load applied from the wheel 9 to the wheel mounting flange 22 is applied to the vicinity of the slime portion 24 and the vicinity of the deepest portion 251 of the recess 25. Be distributed. As a result, the stress concentration in the vicinity of the sewn portion 24 is relaxed, and the strength of the inner member 2 can be increased. Further, in the present embodiment, since the minimum diameter D _{1 of the recess 25 is larger than the minimum diameter D 2 of the} recess 24, excessive stress concentration is suppressed in the vicinity of the deepest portion 251 of the recess 25. Then, the stress is appropriately dispersed in the vicinity of the slime portion 24 and the vicinity of the deepest portion 251 of the recess 25.

Further, in the present embodiment, since the second seal lip 612c of the first sealing device 61 is in sliding contact with the inner surface of the recess 25, the intrusion of foreign matter into the annular space 10 is suppressed. Further, in the present embodiment, since the labyrinth seal S is formed between the top portion 231 of the brim portion 23 and the main body 31 of the outer member 3, for example, the sealing performance of the sealing member 612 deteriorates due to long-term use. Even in this case, it is possible to suppress the invasion of foreign matter into the annular space 10.

Furthermore, in the present embodiment, since the recess 25 can be formed by the same turning process as that of the sewn portion 24, it is possible to suppress an increase in manufacturing cost.

[Modification example]
Next, the wheel bearing device according to the modified example of the embodiment will be described with reference to FIG. FIG. 3A is a cross-sectional view showing a part of the wheel bearing device according to the modified example. FIG. 3B is a partially enlarged view of FIG. 3A. In FIGS. 3A and 3B, the components common to those described in the above-described embodiment are designated by the same reference numerals as those shown in FIGS. 1 and 2 and duplicated explanations are given. Omit.

In the above embodiment, the case where the labyrinth seal S is formed between the top portion 231 of the brim portion 23 and the main body 31 of the outer member 3 has been described. The distance between the outer member 3 and the main body 31 is wider than that in the above embodiment, and the second seal lip 612c of the first sealing device 61 is in sliding contact with the outer peripheral surface 23b of the top portion 231 of the brim portion 23. Further, in this modification, the seal member 621 of the first sealing device 61 has a third seal lip 612d, and the third seal lip 612d is inside the first seal lip 612a and is a wheel. It is in sliding contact with the end surface 22a of the mounting flange 22 on the vehicle inner side. Further, in the above embodiment, the case where the radial position of the deepest portion 251 of the recess 25 is outside the radial position of the brim surface 23a has been described, but in this modification, the recess 25 The deepest portion 251 is formed at a position where it is aligned with the brim surface 23a in the axial direction.

Also in this modification, the minimum diameter D ₁ of the recess 25 is larger than the minimum diameter D _{2 of} the recess 24, and the position of the deepest portion 251 of the recess 25 is outside the extension line L of the inner raceway surface 2a. be.

Also in this modification, the stress generated in the inner member 2 due to the load applied to the wheel mounting flange 22 is dispersed in the vicinity of the slime portion 24 and the vicinity of the deepest portion 251 of the recess 25, as in the above embodiment. , It becomes possible to increase the strength of the inner member 2.

(Additional note)
Although the present invention has been described above based on the embodiments and modifications thereof, these embodiments and modifications do not limit the invention according to the claims. It should also be noted that not all combinations of features described in the embodiments and modifications are essential to the means for solving the problems of the invention.

Further, the present invention can be carried out by appropriately modifying it by omitting a part of the configuration or adding or replacing the configuration within a range not deviating from the gist thereof. For example, in the above embodiment, the case where the present invention is applied to a wheel bearing device that supports a driven wheel in which the driving force of a driving source such as an engine is not transmitted has been described, but the driving force is transmitted via a drive shaft. It is also possible to apply the present invention to a wheel bearing device that supports a drive wheel.

1 ... Wheel bearing device 10 ... Annular space 2 ... Inner member 22 ... Wheel mounting flange 23 ... Brim portion 23a ... Brim surface 231 ... Top 24 ... Smear portion 25 ... Recessed portion 25a ... Inner surface 2a ... First inner raceway surface 2b ... Second inner raceway surface 3 ... Outer member 3a ... First outer raceway surface 3b ... Second outer raceway surface 4 ... First rolling element (conical roller bearing)
41 ... Large diameter part 412 ... Recessed part 42 ... Small diameter part 5 ... Second rolling element 61 ... First sealing device 611 ... Metal member 612 ... Sealing member 612c ... Second seal lip 9 ... Wheel O ... Rotating axis S … Labyrinth seal

Claims (3)

The first and second inner raceway surfaces are arranged in a double row on the outer periphery, and the inner member having a wheel mounting flange to which the wheels are mounted, and the first and second inner raceway surfaces. A tubular outer member having first and second outer raceway planes facing each other formed on the inner circumference, and a plurality of first ones rolling on the first inner raceway plane and the first outer raceway plane. A rolling element and a plurality of second rolling elements that roll on the second inner raceway surface and the second outer raceway surface are provided, and the inner member rotates around the rotation axis with respect to the outer member. A rotating wheel bearing device
The first inner raceway surface is formed on the wheel mounting flange side with respect to the second inner raceway surface.
The first rolling element is a conical roller having a large diameter portion at one end in the axial direction on the wheel mounting flange side and a small diameter portion at the other end in the axial direction.
The inner member has an annular brim portion that has a brim surface facing the large diameter portion of the conical roller and is formed so as to project from the first inner ring raceway surface toward the outer member. In addition to having, an annular slime portion is formed between the first inner raceway surface and the brim surface.
An annular recess formed so as to be recessed toward the rotation axis is formed between the top, which is the end on the outer diameter side of the brim, and the wheel mounting flange.
The minimum diameter of the recess is larger than the minimum diameter of the recess.
Bearing device for wheels. A labyrinth seal is formed between the outer member and the top of the brim to prevent foreign matter from entering the annular space in which the plurality of first and second rolling elements are housed.
The wheel bearing device according to claim 1. A sealing device in which a metal member fitted to the outer member and a sealing member made of an elastic body are integrally formed is attached to one end of the outer member on the wheel mounting flange side.
The sealing member has a lip that slides into contact with the inner surface of the recess.
The wheel bearing device according to claim 1 or 2.

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