WO2019189421A1

WO2019189421A1 - Bearing device for wheels

Info

Publication number: WO2019189421A1
Application number: PCT/JP2019/013290
Authority: WO
Inventors: 荘太鯉住
Original assignee: Ntn株式会社
Priority date: 2018-03-28
Filing date: 2019-03-27
Publication date: 2019-10-03

Abstract

Provided is a bearing device for wheels, which has an increased number of balls and in which the easiness of mounting the balls is increased. A bearing device 1 for wheels is provided with: an outer ring 2 provided with outer raceway surfaces 2c, 2d; an inner member having a hub ring 3 and an inner ring 4 and having double-row inner raceway surfaces 3c, 4a formed thereon; balls 8 contained in a rollable manner between the raceway surfaces of the outer ring 2 and of the inner member; and a retainer 7 which is provided with a base 7a and with columns 7b arranged at fixed intervals in a circumferential direction and extending in the axial direction thereof from the base 7a, and has pockets Pt each formed surrounded by adjacent columns 7b and a base 7a which is located between the adjacent columns 7b, the pockets Pt retaining the balls 8. Each of the columns 7b of the retainer 7 is provided with latch sections 7e protruding toward adjacent columns 7b and with cutouts. The front ends of the latches 7e are located within an annular range having a radial width R1 defined between the outer peripheral circle of a ball 8 and a reference imaginary circle C1 having a diameter D1 centered on the center of the ball 8.

Description

Wheel bearing device

The present invention relates to a wheel bearing device.

Conventionally, a wheel bearing device that supports a wheel rotatably in a suspension device of an automobile or the like is known. In the wheel bearing device, an inner member including a hub ring is rotatably supported by an outer member via a plurality of rolling elements (here, balls). The plurality of balls are equally distributed in the circumferential direction by the cage and are held in a state in which contact between adjacent balls is prevented.

In such a wheel bearing device, by reducing the thickness in the circumferential direction of the pillar portion of the cage that partitions adjacent balls, and forming a notch in the pillar portion to increase the number of balls. It is known that the cage can be made to have a problem of lack of strength and the bearing life can be increased. For example, as described in Patent Document 1.

In the wheel bearing device described in Patent Document 1, the circumferential thickness of the pillar portion of the resin cage is reduced, and a notch is formed in a portion where adjacent balls are closest to each other. Has been. That is, the adjacent balls do not have a pillar portion in the closest part. Thereby, the wheel bearing device can increase the number of balls without increasing the pitch circle diameter of the balls.

JP 2005-180630 A

In the cage of Patent Document 1, the thickness in the circumferential direction of the column portion is reduced in order to reduce the distance between adjacent balls. For this reason, when the ball is incorporated into the cage, the ball assemblability may be lowered.

The present invention has been made in view of the above situation, and an object of the present invention is to provide a wheel bearing device capable of improving the incorporation of balls into a cage while increasing the number of balls.

That is, the first invention is press-fitted into an outer member having a double row outer raceway surface on the inner periphery, a hub wheel having a small diameter step portion extending in the axial direction on the outer periphery, and the small diameter step portion. An inner member having at least one inner ring and provided with a double row inner raceway surface facing the double row outer raceway surface on the outer periphery, and both raceway surfaces of the outer member and the inner member Adjacent pillars having a double row of balls accommodated in a freely rolling manner, a base formed in an annular shape, and a plurality of pillars extending in the axial direction from the base at regular intervals in the circumferential direction A bearing having a curved surface along the outer peripheral surface of the ball, and a cage made of resin that holds the ball in the pocket. The portion has a claw portion protruding toward an adjacent column portion, and the column At least one has a notch portion from the tip to the base, and the tip of the claw is a reference virtual circle having a predetermined radius centered on the center of the ball and the outer periphery of the ball as viewed in the axial direction. It is included in an annular range surrounded by a circle.

The second invention is a wheel bearing device in which a guide surface along a virtual circle having an arbitrary radius from the center of the ball is formed at a tip portion of the claw portion.

A third invention is for a wheel in which the pocket is configured by a hemispherical curved surface having the base as a bottom and a guide surface extending in an axial direction from an edge of the hemispherical curved surface toward a tip of the column portion. It is a bearing device.

A fourth invention is a wheel bearing device in which a diameter of a reference virtual circle having the predetermined radius is 0.8 times or more and less than 1 time of the diameter of the ball.

According to a fifth aspect of the invention, the column portion includes an inner column provided on an inner diameter side of the notch portion and an outer column provided on an outer diameter side of the notch portion, and the axial direction of the inner column The end surface is a wheel bearing device that is offset toward the center of the ball from the axial end surface of the outer column.

According to a sixth aspect of the present invention, there is provided an outer member having a double row outer raceway surface on the inner periphery, a hub wheel having a small-diameter step portion extending in the axial direction on the outer periphery, and at least press-fitted into the small-diameter step portion. An inner member having a single inner ring and provided on the outer periphery with a double-row inner raceway surface facing the double-row outer raceway surface, and between both raceway surfaces of the outer member and the inner member Adjacent to each other, a double row of balls accommodated in a freely rollable manner, a base portion formed in an annular shape, and a plurality of pillar portions extending in the axial direction at regular intervals in the circumferential direction from the base portion A pocket having a curved surface along the outer peripheral surface of the ball, and a cage made of resin that holds the ball in the pocket. On the outer column and inner side by a notch from the tip to the base The outer column is formed with a claw portion that protrudes toward the adjacent outer column, and when the ball is incorporated into the cage, the inner column and the claw portion are adjacent to each other. The diameter of an imaginary circle passing through the points where the balls are in contact with each other is 0.9 times or more and less than 1 time the diameter of the balls.

As the effects of the present invention, the following effects are obtained.

That is, according to the first aspect of the invention, the number of balls can be increased because the notch for bringing adjacent balls close to the pillar portion of the cage is formed. In addition, since the range where the claw portion of the cage overlaps with the ball in the axial direction view of the cage is limited, when inserting a plurality of balls into the cage pocket along the axial direction of the cage The amount of deformation of the pillar portion of the cage is suppressed. Thereby, the bearing device for wheels can improve the incorporation property of a ball, increasing the number of balls built in a cage.

According to the second invention, when the plurality of balls are inserted into the cage pocket along the axial direction of the cage, the contact position between the claw portion and the ball by the guide surface formed on the claw portion of the cage. Approaches the outer circle of the ball. Thereby, even if the notch part for making a ball approach the pillar part of a cage | basket is formed in the wheel bearing apparatus, it can suppress a deformation | transformation of the pillar part at the time of ball | bowl incorporation.

According to the third invention, when a plurality of balls are inserted into the cage pocket along the axial direction of the cage, if the balls pass through the claw portion of the cage, the pillar portion of the cage is pushed by the balls. I can't spread it. Thereby, even if the notch part for making a ball approach the pillar part of a cage | basket is formed in the wheel bearing apparatus, it can suppress a deformation | transformation of the pillar part at the time of ball | bowl incorporation.

According to the fourth aspect of the present invention, the range in which the claw portion of the cage overlaps with the ball when viewed in the axial direction of the cage is limited to less than 10% of the diameter of the ball. Thus, the amount of deformation of the retainer column when inserting a plurality of balls into the pocket of the retainer is limited. Thereby, even if the notch part for making a ball approach the pillar part of a cage | basket is formed in the wheel bearing apparatus, it can suppress a deformation | transformation of the pillar part at the time of ball | bowl incorporation.

According to the fifth invention, the axial end surface of the inner column is offset closer to the center side of the ball than the axial end surface of the outer column, and a virtual circle is set by the inner column and the claw portion. Compared to a configuration in which a virtual circle is set by an inner column having an axial end surface whose axial end surface coincides with the axial end surface, the diameter of the virtual circle can be increased, and the design freedom of the claw portion is improved. can do.

According to the sixth invention, since the range in which the pillar portion of the cage overlaps with the ball is limited, the amount of deformation of the pillar portion of the cage when inserting a plurality of balls into the pocket of the cage is small. It is suppressed. Thereby, even if the notch part for making a ball approach the pillar part of a cage | basket is formed in the wheel bearing apparatus, it can suppress a deformation | transformation of the pillar part at the time of ball | bowl incorporation.

The perspective view which shows the whole structure in 1st embodiment of the wheel bearing apparatus. Sectional drawing which shows the whole structure in 1st embodiment of the wheel bearing apparatus. The enlarged step view which shows the structure of the ball | bowl and the holder | retainer in 1st embodiment of the wheel bearing apparatus. The perspective view which shows the whole structure of the holder | retainer in 1st embodiment of the wheel bearing apparatus. (A) The top view which shows the whole structure of the holder | retainer in 1st embodiment of the wheel bearing apparatus, (b) The side view which similarly shows the whole structure of a holder | retainer. (A) The elements on larger scale which show the relationship between the nail | claw part of a holder | retainer and a ball | bowl in 1st embodiment of a wheel bearing apparatus, (b) The elements on larger scale which show the notch part of a holder | retainer similarly. (A) Partial enlarged plan view showing a state before the ball is incorporated into the cage in the first embodiment of the wheel bearing device, (b) Partial enlarged plan view showing a state during the incorporation of the ball into the cage. (C) The elements on larger scale which show the state after the assembly | attachment of the ball | bowl to a cage | basket similarly. (A) The partial expansion perspective view which shows the relationship between the nail | claw part of a holder | retainer and a ball | bowl in 2nd embodiment of a wheel bearing apparatus, (b) The nail | claw part at the time of changing the length of the pillar part of a holder | retainer similarly The partial expansion perspective view which shows the relationship with a ball | bowl.

Hereinafter, the wheel bearing device 1 which is an embodiment of the wheel bearing device according to the present invention will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1 and FIG. 2, the wheel bearing device 1 supports a wheel rotatably in a suspension device of a vehicle such as an automobile. The wheel bearing device 1 includes an outer ring 2 that is an outer member, a hub wheel 3 that is an inner member, an inner ring 4, two inner side ball rows 5 that are rolling rows, an outer side ball row 6, and a seal member. An inner side sealing member 9 and an outer side sealing member 16 which is a sealing member are provided. The inner side seal member 9 and the outer side seal member 16 are wheel bearing seals. Here, in this specification, the inner side means the vehicle body side of the wheel bearing device 1 when the wheel bearing device 1 is attached to the vehicle body, and the outer side means that the wheel bearing device 1 is attached to the vehicle body. The wheel side of the wheel bearing device 1 in this case is shown. The direction parallel to the rotation axis of the wheel bearing device 1 is “axial direction”, the direction orthogonal to the rotation axis of the wheel bearing device 1 is “radial direction”, and the rotation axis of the wheel bearing device 1 is the center. The direction along the arc is represented as “circumferential direction”.

As shown in FIG. 2, the outer ring 2 supports the hub ring 3 and the inner ring 4 via the inner side ball row 5 and the outer side ball row 6. The outer ring 2 is formed in a substantially cylindrical shape. An inner side opening 2 a into which the inner side seal member 9 can be fitted is formed at the inner side end of the outer ring 2. An outer side opening 2b into which the outer side seal member 16 can be fitted is formed at the outer side end of the outer ring 2.

On the inner peripheral surface of the outer ring 2, an outer raceway surface 2c on the inner side and an outer raceway surface 2d on the outer side are provided. On the outer peripheral surface of the outer ring 2, a vehicle body attachment flange 2 e for attaching to a knuckle of a suspension device (not shown) is integrally formed.

The hub wheel 3 rotatably supports a vehicle wheel (not shown). The hub wheel 3 is formed in a cylindrical shape. A small-diameter step portion 3 a having a reduced diameter on the outer peripheral surface is formed at the inner side end of the hub wheel 3. A wheel mounting flange 3b for mounting a wheel is integrally formed at an outer side end portion of the hub wheel 3. Hub bolts 3d are inserted through the wheel mounting flanges 3b at circumferentially equidistant positions. Further, the hub wheel 3 is disposed such that the inner raceway surface 3 c on the outer side faces the outer raceway surface 2 d on the outer side of the outer ring 2. A serration (or spline) for torque transmission is formed on the inner periphery of the hub wheel 3. In the hub wheel 3, an inner ring 4 is fitted in a small diameter step portion 3 a.

The inner ring 4 gives a preload to the inner side ball row 5 and the outer side ball row 6. On the outer circumferential surface of the inner ring 4, an annular inner raceway surface 4a is formed in the circumferential direction. The inner ring 4 is fixed to the inner side end of the hub ring 3 by caulking. That is, the inner raceway 4 a is formed by the inner ring 4 on the inner side of the hub ring 3. The inner ring 4 is disposed such that the inner raceway surface 4 a faces the outer raceway surface 2 c on the inner side of the outer ring 2.

In the inner side ball row 5 and the outer side ball row 6, a plurality of balls 8 which are rolling elements are held in a ring shape by a resin cage 7. The inner side ball row 5 is sandwiched between the inner raceway surface 4a of the inner ring 4 and the outer raceway surface 2c on the inner side of the outer ring 2 so as to freely roll. The outer side ball row 6 is sandwiched between the inner raceway surface 3c of the hub wheel 3 and the outer raceway surface 2d on the outer side of the outer ring 2 so as to be able to roll. That is, the inner side ball row 5 and the outer side ball row 6 support the hub ring 3 and the inner ring 4 so as to be rotatable with respect to the outer ring 2. In the wheel bearing device 1, a double row angular ball bearing is constituted by an outer ring 2, a hub ring 3 or an inner ring 4, and an inner side ball row 5 and an outer side ball row 6 sandwiched therebetween. The wheel bearing device 1 is configured such that an outer ring 2 and an inner ring 4 are relatively rotatable by an inner side ball row 5 and an outer side ball row 6 (see FIG. 2).

The holder 7 holds the ball 8. The cage 7 is made of a synthetic resin excellent in oil resistance, wear resistance and lubricity, such as polyamide 46 (PA46), polyamide 66 (PA66), polyamide 9T (PA9T), polyetheretherketone (PEEK), polyphenylene sulfide ( PPS) and the like. In the cage 7 of the present embodiment, glass fiber (GF) or carbon fiber (CF) or the like is kneaded and molded into resin as a reinforcing material.

As shown in FIG. 3, the cage 7 is formed of a base portion 7a and a column portion 7b. The base 7a is formed in an annular shape. The column part 7b protrudes from the base part 7a in the axial direction. The column portions 7b are arranged at equal intervals along the circumferential direction of the base portion 7a. In the cage 7, pockets Pt for independently holding the balls 8 are formed at equal intervals between the adjacent column portions 7b (see FIG. 4).

The ball 8 is rotatably held in the pocket Pt of the retainer 7 via grease which is a lubricant filled between the outer ring 2 and the inner ring 4.

The inner side seal member 9 closes the gap between the inner side opening 2 a of the outer ring 2 and the inner ring 4. The inner side seal member 9 is composed of, for example, a two-side lip type pack seal that contacts two seal lips 12. The inner side sealing member 9 includes a substantially cylindrical sealing plate 10 and a substantially cylindrical slinger 13.

A seal plate 10 is configured by fixing a seal lip 12 (refer to a thin ink section) to a substantially cylindrical core 11. The metal core 11 is made of metal, for example, a ferritic stainless steel plate (JIS standard SUS430 series or the like), an austenitic stainless steel sheet (JIS standard SUS304 system or the like), or a rust-proof cold rolled steel plate (JIS standard). Standard SPCC system). The cored bar 11 is formed in a substantially L shape in an axial sectional view. The seal lip 12 is, for example, NBR (acrylonitrile-butadiene rubber), HNBR (hydrogenated acrylonitrile-butadiene rubber) excellent in heat resistance, EPDM (ethylene propylene rubber), ACM (polyacrylic excellent in heat resistance and chemical resistance) Rubber), FKM (fluoro rubber), or synthetic rubber such as silicon rubber. The seal plate 10 is fitted into the inner side opening 2 a of the outer ring 2.

The slinger 13 is made of, for example, a steel plate made of the same material as the seal plate 10. The slinger 13 is formed in a substantially L shape in an axial sectional view. The slinger 13 is fitted to the inner ring 4. The slinger 13 is disposed on the inner side of the seal plate 10 so as to face the seal plate 10.

Thus, the inner side seal member 9 constitutes a pack seal from the seal plate 10 fitted to the inner side opening 2 a of the outer ring 2 and the slinger 13 fitted to the inner ring 4. The seal lip 12 of the seal plate 10 is in contact with or close to the slinger 13 via an oil film, and mainly prevents leakage of grease inside the wheel bearing device 1 to the outside or entry of muddy water or the like from the outside. ing. In the following embodiments, the inner seal member 9 may be a pack seal provided with one or a plurality of seal lips 12.

As shown in FIG. 2, the outer side seal member 16 closes the gap between the outer side opening 2 b of the outer ring 2 and the hub ring 3. The outer side seal member 16 has a seal lip 14 fixed to a substantially cylindrical cored bar 15.

The core 15 of the outer side sealing member 16 is, for example, a ferritic stainless steel plate (JIS standard SUS430 series or the like), an austenitic stainless steel sheet (JIS standard SUS304 series or the like), or a rust-proof cold rolled steel plate. (JIS standard SPCC system, etc.). The cored bar 15 is formed in a substantially L shape in an axial sectional view. The seal lip 14 is, for example, NBR (acrylonitrile-butadiene rubber), HNBR (hydrogenated acrylonitrile-butadiene rubber) excellent in heat resistance, EPDM (ethylene propylene rubber), ACM (polyacrylic) excellent in heat resistance and chemical resistance. Rubber), FKM (fluoro rubber), or synthetic rubber such as silicon rubber.

The metal core 15 is fitted into the outer opening 2b of the outer ring 2. At this time, the outer side seal member 16 is disposed so that the seal lip 14 contacts the seal sliding surface of the hub wheel 3 via an oil film. The outer side seal member 16 is configured to be slidable with respect to the seal sliding surface. Thereby, the seal lip 14 prevents leakage of lubricating grease from the outer side opening 2b of the outer ring 2 and entry of rainwater or muddy water from the outside.

In the wheel bearing device 1 configured as described above, the hub ring 3 and the inner ring 4 include an inner side ball row 5 and an outer side ball row in which a plurality of balls 8 are held at equal intervals by a cage 7. 6 and is supported rotatably. Further, in the wheel bearing device 1, the gap between the inner side opening 2 a and the inner ring 4 of the outer ring 2 is closed by the inner side seal member 9, and the gap between the outer side opening 2 b of the outer ring 2 and the hub ring 3 is closed. The outer side sealing member 16 is closed. As a result, the wheel bearing device 1 prevents leakage of lubricating grease from the inside and entry of rainwater or muddy water from the outside.

Hereinafter, the cage 7 will be described in detail with reference to FIGS. 3 to 6. In the following description, the radial direction indicates the radial direction of the base portion 7a of the cage 7. An axial direction shall show the axial direction of the base 7a. The circumferential direction indicates the circumferential direction of the base portion 7a.

As shown in FIG. 3, the base 7 a is located on the inner diameter side of the pitch circle PCD of the ball 8. In the present embodiment, the entire base portion 7a is located on the inner diameter side with respect to the pitch circle PCD, but a part of the base portion 7a may be located on the outer diameter side with respect to the pitch circle PCD. In FIG. 3, D _PCD indicates the pitch circle PCD of the ball 8.

The inner diameter surface of each column portion 7b extends in the axial direction. The outer diameter surface of the column portion 7b includes a first portion extending obliquely from the tip of the base portion 7a so as to be separated from the outer peripheral surface of the base portion 7a in the radial direction, and a second portion extending horizontally from the first portion in the axial direction. And have a part. That is, the column part 7b has a part where the radial width increases from the base part 7a toward the tip. The outer diameter surface of the column portion 7b protrudes outward in the axial direction from the inner diameter surface of the column portion 7b.

As shown in FIG. 4 and FIG. 5 (a), the center is located at a predetermined position P (FIG. 3) in the part constituted by the base 7a side of the side surface facing the adjacent pillar 7b and the base 7a therebetween. A concave curved surface 7c is formed in a substantially hemispherical shape with the base portion 7a as a bottom portion along the outer peripheral surface of the ball 8 arranged so as to come to the reference). Furthermore, a guide surface 7d extending in the axial direction from the edge of the hemispheric concave curved surface 7c toward the tip of the column portion 7b is formed on the column portion 7b. The guide surface 7d is curved with the same curvature as that of the edge of the concave curved surface 7c when viewed in the axial direction. 7 d of guide surfaces are comprised so that the ball | bowl 8 may be guide | induced to the space enclosed by the concave curved surface 7c from the front-end | tip of the pillar part 7b. Thereby, in the cage 7, pockets Pt for holding the balls 8 from the concave curved surface 7c and the guide surface 7d are formed at equal intervals between the adjacent column portions 7b.

As shown in FIG. 5A, the minimum distance between the adjacent balls 8 on the pitch circle PCD is regulated by the balls 8 coming into contact with the inner surface of the column portion 7b. The thickness of the column part 7b is the thinnest on the pitch circle PCD, and gradually becomes thicker as it is further away from the inner diameter side and the outer diameter side.

As shown in FIGS. 5 (a) and 5 (b), the concave curved surface 7c and the guide surface 7d of the columnar portion 7b are curved with the substantially central portion of the radial width of the columnar portion 7b as the bottom as viewed in the axial direction. ing. The interval between the adjacent column portions 7b is formed such that the interval Wi between the radially inner ends and the interval Wo between the radially outer ends are smaller than the interval Wc between the substantially radial centers. Thereby, the pillar part 7b has controlled the movement to the radial inside and radial outside of the ball 8 arrange | positioned inside the pocket Pt. A claw portion 7e that protrudes toward the adjacent column portion 7b (on the pocket Pt side) is formed at the tip portion of the column portion 7b. That is, the claw portion 7e protrudes from the tip end portion of the column portion 7b to both sides in the circumferential direction.

As shown in FIG. 6A, the tip of the claw portion 7e is surrounded by a reference virtual circle C1 having a diameter D1 centered on a predetermined position P and an outer circumference circle C0 of the ball 8 having a diameter D0 as viewed in the axial direction. It is formed so as to be included in an annular range (light ink portion) having a radial width R1. The reference virtual circle C1 is concentric with the outer circumference circle C0 of the ball 8, and the diameter D1 of the reference virtual circle C1 is smaller than the diameter D0 of the outer circumference circle C0. Specifically, the diameter D1 of the reference virtual circle C1 is set to be 0.8 times or more and less than 1 time the diameter D0 of the ball 8.

The tip part on the pocket Pt side of the claw part 7e is cut out in a chamfered shape so as to be included in the radial width R1. The tip of the claw portion 7e has an arc surface along a virtual circle Ca having an arbitrary diameter Da that is larger than the reference virtual circle C1 having the diameter D1 and smaller than the outer circumference circle C0 of the ball 8 having the diameter D0 in the axial direction. A certain guide surface 7f is formed. The diameter of the virtual circle Ca is larger than the diameter of the reference virtual circle C1 and smaller than the diameter of the outer circumference circle C0 of the ball 8. Further, the tip of the claw portion 7e is configured so as to contact the outer peripheral surface of the ball 8 whose center is disposed at a predetermined position P (see FIG. 3). Thereby, the pillar part 7b has controlled the movement to the axial direction of the ball | bowl 8 arrange | positioned in the pocket Pt by the nail | claw part 7e. The guide surface 7f is formed as a curved surface along the virtual circle Ca, but may be a plane that approximates the virtual circle Ca.

As shown in FIG. 6 (b), at the substantially central portion of the radial width of the column portion 7b, a slit portion 7gα having a radial width W and an axial length L and a radius R from the tip toward the base portion 7a side. A notch portion 7g having a curved surface portion 7gβ is formed. The bottom of the notch 7g (curved surface 7gβ) is provided on the base 7a side with respect to the center P of the ball 8. Thus, in the ball center P where the distance between the adjacent balls 8 is the shortest, the bottom of the notch 7g is provided closer to the base 7a than the center P, so that the distance between the balls 8 is shortened. And the number of balls 8 can be increased.

The curved surface portion 7gβ is provided at the end portion of the slit portion 7gα. The column portion 7b is branched into a radially outer portion column (hereinafter simply referred to as “outer column 7h”) and a radially inner portion column (hereinafter simply referred to as “inner column 7i”) by the notch portion 7g. Is done. The aforementioned claw portion 7e is formed at the tip of the outer column 7h. The notch 7g is formed so as to remove a portion that does not have the necessary strength around the substantially central portion in the radial direction where the thickness of the column portion 7b is the thinnest by the concave curved surface 7c and the guide surface 7d. . As a result, the cage 7 can ensure the strength of the column portion 7b even if the number of the balls 8 to be held by increasing the distance between the balls 8 on the pitch circle PCD is increased. Since the number of balls 8 can be increased in this way, the bearing load applied to each ball 8 is reduced, the life of the wheel bearing device 1 is improved, and the weight and size of the wheel bearing device 1 are reduced. Can be realized.

Further, the center P of the ball 8 is provided within the range of the radial width of the notch 7g. In the present embodiment, the center P of the ball 8 is provided on the outer diameter side with respect to the radial width center of the notch 7g.

The radius R of the notch 7g is set to be larger than 0.05 times and smaller than 0.3 times with respect to the diameter D0 of the ball 8 (0.05 <R / D0 <0.3). ). When the radius R is less than 0.05 times the diameter D0 of the ball, the assemblability of the ball 8 into the cage 7 is deteriorated. When the radius R exceeds 0.3 times the diameter D0 of the ball 8, the rigidity of the cage 7 decreases. The radial width W of the notch 7g is set to be larger than 0.2 times and smaller than 0.5 times the diameter D0 of the ball 8 (0.2 <W / D0). <0.5). If the radial width W is less than 0.2 times the diameter D0 of the ball 8, the ball 8 cannot be incorporated. When the radial width W exceeds 0.5 times the diameter D0 of the ball 8, the shape without the column portion 7b is formed, and the ball 8 cannot be held.

By forming the inner side ball row 5 and the outer side ball row 6 from the cage 7 and the ball 8 formed in this way, the wheel bearing device 1 includes the outer ring 2, the hub ring 3, and the inner ring 4. The relative position accuracy is improved, and an equal load can be received in all radial directions. Further, the inner side ball row 5 and the outer side ball row 6 are each supported by the balls 8 independently by the pockets Pt of the cage 7, so that wear and contact noise due to contact between the balls 8 may occur. Absent. Thus, in this embodiment, the adjacent balls 8 are held by the holder 7 so as to face each other directly and non-contactingly on the pitch circle PCD.

3 and 6A, the axial end surface S1 of the inner column 7i is offset to the center P side (base 7a side) of the ball 8 from the axial end surface S2 of the outer column 7h. The axial end face S1 of the inner column 7i is provided on the outer side in the axial direction from the center P of the ball 8. The virtual circle Ca is defined by passing through a point where the ball simultaneously contacts the adjacent inner pillar 7i and the claw portion 7e. Thus, since the virtual circle Ca is set by the inner column 7i and the claw portion 7e offset from the axial end surface S2 of the outer column 7h to the center P side of the ball 8, the axial end surface and the axial direction of the outer column are set. The diameter D1 of the virtual circle Ca can be increased as compared with the configuration in which the virtual circle is defined by the inner column and the claw portion having the axial end faces that coincide with each other. Therefore, by defining the axial position of the inner column 7i, it becomes easy to set the virtual circle Ca in the range of the radial width R1 (0.8 times or more and less than 1 times the diameter D0 of the ball 8). The degree of freedom in design of the tip end portion of 7e can be improved. For example, the virtual circle Ca can be included in the range of the radial width R1 without limiting the tip of the claw 7e to the shape of the present embodiment (notched in an arc shape).

Hereinafter, the deformation state of the cage 7 when the ball 8 is incorporated into the cage 7 from the axial direction will be described with reference to FIG. Note that the ball 8 is moved only in the axial direction by a ball insertion tool (not shown) or the like.

As shown in FIG. 7 (a), when a ball is assembled in the pocket Pt of the cage 7, the ball 8 is positioned on the column portion 7b of the cage 7 with the center overlapping the predetermined position P as viewed in the axial direction. It is inserted from the distal end side toward the base portion 7a along the axial direction. The outer surface of the ball 8 contacts the guide surface 7f of the claw portion 7e formed at the tip of the column portion 7b on both sides of the pocket Pt. The guide surface 7f of each claw portion 7e is a virtual circle having an arbitrary diameter Da set to a radial width R1 (see FIG. 6) that is 0.8 times or more and less than 1 time the diameter D0 of the ball 8 in the axial direction. It is in contact with the outer peripheral surface of the ball 8 at a position overlapping with Ca.

When an external force is applied to move the ball 8 toward the base portion 7a, the claw portion 7e slides on the outer peripheral surface of the ball 8 toward the outer peripheral circle C0 of the ball 8 when viewed in the axial direction. At this time, a force Fc (thin ink arrow) in a direction connecting the center of the ball 8 and the contact position on the outer peripheral surface is applied to the claw portion 7e from the adjacent balls 8. As a result, a resultant force Fr (a dark thin ink arrow) is applied to the claw portion 7e by combining the force Fc and moving outward in the radial direction.

As shown in FIG. 7B, when the ball 8 moves to the base portion 7a side, the outer column 7h in which the claw portion 7e is formed is pushed outward in the radial direction in the column portion 7b by the generated resultant force Fr. The outer column 7h is pushed outward in the radial direction until the tip of the claw portion 7e reaches the outer circumferential circle C0 of the ball 8 as viewed in the axial direction. The outer column 7h is elastically deformed radially outward by a maximum of about 0.1 times the diameter D0 of the ball 8 (equivalent to the radius of the virtual circle Ca having an arbitrary diameter Da). At this time, the stress generated in the column portion 7b is suppressed to less than the allowable limit stress determined from the characteristics of the material of the cage 7 because the shapes of the claw portion 7e and the notch portion 7g are limited. .

As shown in FIG. 7C, the ball 8 passes through the claw portion 7e and reaches the guide surface 7d of the column portion 7b by deformation of the outer column 7h outward in the radial direction. The column portion 7b slides on the outer circumferential surface of the ball 8 from the outer circumferential circle C0 of the ball 8 toward the inner side in the radial direction as viewed in the axial direction by the elastic force of the claw portion 7e. The ball 8 is moved in the axial direction along the guide surface 7d and reaches the concave curved surface 7c. The nail | claw part 7e stops in the position which overlaps with the virtual circle Ca of arbitrary diameter Da by axial direction view. The ball 8 is restricted from moving radially outward and radially inward by the concave curved surface 7c and the guide surface 7d, and restricted by the claw portion 7e in the axial direction. Thereby, the balls 8 are held at equal intervals by the holder 7.

In this way, the guide surface 7f of the claw portion 7e brings the contact position between the claw portion 7e and the ball 8 close to the outer circumference circle C0 of the ball 8 when viewed in the axial direction, so that the claw portion 7e overlaps the ball 8 when viewed in the axial direction. This range is limited to about 0.1 times the diameter D0 of the ball 8 at the maximum. Further, if the ball 8 passes through the claw portion 7 e, the column portion 7 b of the cage 7 is not pushed and spread by the ball 8. Accordingly, the cage 7 can suppress the deformation amount of the column portion 7b when the plurality of balls 8 are inserted into the pockets Pt of the cage 7 along the axial direction. Thereby, the wheel bearing device 1 can improve the assemblability of the ball 8 even if the notch portion 7g is formed in the column portion 7b.

Table 1 shows the evaluation results regarding the incorporation of the ball 8 when the diameter D1 of the reference virtual circle C1 is changed with respect to the diameter D0 of the ball 8. In Table 1, “◯” means that the pillar portion of the cage was not broken when the ball was assembled, and “x” means that the pillar portion of the cage was broken when the ball was assembled.

From Table 1, the diameter D1 of the reference virtual circle C1 connected at the contact point between the ball 8 and the column portion 7b of the cage 7 when the ball 8 is assembled into the cage 7 is 0.8. It has been found that it is optimal to set the ratio at least twice or less than one time.

In addition, although all the column parts 7b in the above-mentioned embodiment each have the notch part 7g, at least 1 pillar part 7b should just have the notch part 7g. In the cage 7, the degree of freedom in the circumferential direction of the other balls 8 is increased by moving the balls 8 adjacent to the pillar portions 7b having the cutout portions 7g outward in the radial direction. Can be improved. It is assumed that a through-hole having a radius R is formed in the column portion 7b that does not have the notch portion 7g. Further, in the above-described embodiment, the example in which the ball 8 is incorporated into the cage 7 from the axial direction has been described.

Next, a second embodiment of the wheel bearing device 1 according to the present invention will be described with reference to FIG. Note that the wheel bearing device 1 according to the following embodiment is applied in place of the wheel bearing device 1 in the wheel bearing device 1 shown in FIGS. The same reference numerals are used to indicate the same components, and in the following embodiments, the same points as those of the embodiments already described will be omitted, and the differences will be mainly described. .

The outer pillar 7h and the inner pillar 7j are formed in the pillar part 7b of the cage 7 by the notch part 7g. A claw portion 7k that protrudes toward the adjacent column portion 7b is formed on the outer column 7h of the column portion 7b. That is, the claw portion 7k protrudes from the tip portion of the column portion 7b to both sides in the circumferential direction. Thereby, the pillar part 7b has controlled the movement to the axial direction of the ball | bowl 8 arrange | positioned in the pocket Pt by the nail | claw part 7k.

When the ball 8 is arranged so as to simultaneously contact each claw portion 7k and each inner column 7j on the pocket Pt side of the adjacent column portion 7b at four points, the ball 8 and each claw portion 7k, and the ball 8 and each inner side A circle connecting the contact point Pc with the column 7j is defined as a virtual circle Cb having a diameter Db. The diameter Db of the virtual circle Cb increases as the length of the inner column 7j decreases (as the tip portion of the inner column 7j moves away from the claw portion 7k).

As shown in FIG. 8B, the diameter Db of the virtual circle Cb can be increased by reducing the length of the inner column 7j by H. The length of the inner column 7j is the outer circumference of the ball 8 projected on the same plane as the virtual circle Cb from the reference virtual circle C2 having the diameter D2 on the same plane as the virtual circle Cb and the same center as the virtual circle Cb. It is determined that the diameter Db of the virtual circle Cb is included in the range up to the circle C0. The virtual circle C2 having a diameter D2 is set to be 0.9 times or more and less than 1 time the diameter D0 of the ball 8. Table 2 shows the evaluation results regarding the incorporation of the ball 8 when the diameter D2 of the reference virtual circle C2 is changed with respect to the diameter D0 of the ball 8. In Table 2, “◯” means that the pillar portion of the cage was not damaged when the ball was assembled, and “x” means that the pillar portion of the cage was broken when the ball was assembled.

According to Table 2, when the ball 8 is assembled into the cage 7 from the axial direction, the diameter D2 of the reference virtual circle C2 connected at the four contact points Pc between the ball 8 and the column portion 7b of the cage 7 is calculated. It has been found that it is optimal to set the diameter D0 to 0.9 times or more and less than 1 time.

Thus, by determining the length of the inner column 7j of the column portion 7b so that the contact position between the inner column 7j and the ball 8 approaches the outer circumference circle C0 of the ball 8, the claw portion 7k and the inner column 7j of the column portion 7b. Is limited to approximately 0.05 times the diameter D0 of the ball 8 at the maximum. Therefore, in the cage 7, the deformation amount of the column portion 7b when the plurality of balls 8 are inserted into the pockets Pt along the axial direction is suppressed. Thereby, even if the notch part 7g is formed in the pillar part 7b of the holder | retainer 7, the wheel bearing apparatus 1 can improve the incorporating property of the ball | bowl 8. FIG.

The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various further modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is shown by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including. In the present embodiment, the wheel bearing device 1 is configured as a third-generation wheel bearing device in which the inner raceway surface 3c is directly formed on the outer periphery of the hub wheel 3. However, the present invention is not limited to this. Rather than a second generation structure in which a pair of inner rings 4 are press-fitted and fixed to the hub ring 3, or a first generation structure in which a double row angular ball bearing is fitted between the knuckle and the hub ring. Good.

DESCRIPTION OF SYMBOLS 1 Wheel bearing apparatus 2 Outer ring 2a Inner side opening part 3 Hub ring 4 Inner ring 7 Cage

7a Base part

7b Column part

7e Claw part

7g Notch part 7h Outer pillar 7i Inner pillar 8 Ball C1 Reference virtual circle Ca Virtual circle Da Virtual circle Diameter S1 Axial end face S2 Axial end face

Claims

An outer member provided with a double-row outer raceway surface on the inner periphery;
A double-row inner track having a hub wheel formed with a small-diameter step portion extending in the axial direction on the outer periphery and at least one inner ring press-fitted into the small-diameter step portion and facing the outer track surface of the double row on the outer periphery An inner member provided with a surface;
A double row of balls accommodated so as to roll between both raceway surfaces of the outer member and the inner member;
A base portion formed in an annular shape and a plurality of column portions extending in the axial direction from the base portion at a constant interval in the circumferential direction, and a curved surface along the outer peripheral surface of the ball by the adjacent column portions and the base portion. A bearing device for a wheel comprising: a pocket having a pocket, and a resin cage for holding the ball in the pocket;
The column part has a claw part protruding toward an adjacent column part,
At least one of the pillars has a notch from the tip toward the base,
A wheel bearing device in which a tip end portion of the claw portion is included in an annular range surrounded by a reference virtual circle having a predetermined radius centered on the center of the ball and an outer peripheral circle of the ball as viewed in the axial direction.
The wheel bearing device according to claim 1, wherein a guide surface along a virtual circle having an arbitrary radius from the center of the ball is formed at a tip of the claw portion.
The said pocket is comprised from the hemispherical curved surface which makes the said base the bottom part, and the guide surface extended in an axial direction toward the front-end | tip of the said column part from the edge of the said hemispherical curved surface. 2. A wheel bearing device according to 2.
The wheel bearing device according to any one of claims 1 to 3, wherein a diameter of a reference virtual circle having the predetermined radius is 0.8 times or more and less than 1 time of the diameter of the ball.
The column portion includes an inner column provided on an inner diameter side than the notch portion and an outer column provided on an outer diameter side than the notch portion,
The axial end surface of the inner column is offset to the center side of the ball from the axial end surface of the outer column,
5. The wheel bearing device according to claim 1, wherein the virtual circle passes through a point where the ball and the claw portion are in contact with each other at the same time.
An outer member provided with a double-row outer raceway surface on the inner periphery;
A double-row inner track having a hub wheel formed with a small-diameter step portion extending in the axial direction on the outer periphery and at least one inner ring press-fitted into the small-diameter step portion and facing the outer track surface of the double row on the outer periphery An inner member provided with a surface;
A double row of balls accommodated so as to roll between both raceway surfaces of the outer member and the inner member;
A base portion formed in an annular shape and a plurality of column portions extending in the axial direction from the base portion at a constant interval in the circumferential direction, and a curved surface along the outer peripheral surface of the ball by the adjacent column portions and the base portion. A bearing device for a wheel comprising: a pocket having a pocket, and a resin cage for holding the ball in the pocket;
In the column portion, an outer column and an inner column are formed by a notch portion from the tip toward the base,
The outer column is formed with a claw portion protruding toward the adjacent outer column,
When the ball is incorporated in the cage, the diameter of a virtual circle that passes through the point where the ball simultaneously contacts the adjacent inner pillar and the claw portion is not less than 0.9 times and less than 1 time the diameter of the ball. A certain wheel bearing device.