JP2011064263A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel, which prevents a contact ellipse of a ball from striking on a shoulder part and prevents the generation of an edge load to improve acoustic characteristics and a service life. <P>SOLUTION: This bearing device for a wheel is composed of double row angular contact ball bearings, wherein the ball diameters do, di of balls 4 in double rows are set to the same, and the shoulder height Ho1, Ho2 of rolling surfaces 1a, 5a on the side to which a large moment load is applied, out of both rolling surfaces of the double rows are set larger than the shoulder height Hi1, Hi2 of the other rolling surfaces 2a, 5b. Further, the angular parts A-D of the shoulder parts of the rolling surfaces 1a, 5a, 2a, 5b are rounded into circular arc shape with the radius of curvature of R 0.15-2.0 and simultaneously formed to be smoothly continuous with a form grinding wheel for forming the rolling surfaces. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wheel bearing device for rotatably supporting a wheel of an automobile or the like, and more particularly, a wheel that prevents the occurrence of an edge load by preventing a shoulder contact of a ball contact ellipse to improve acoustic characteristics and life. The present invention relates to a bearing device.

  2. Description of the Related Art Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like is such that a hub wheel for mounting a wheel is rotatably supported via a rolling bearing, and there are a drive wheel and a driven wheel. For structural reasons, an inner ring rotation method is generally used for driving wheels, and an inner ring rotation method and an outer ring rotation method are generally used for driven wheels. As the wheel bearing device, a double-row angular ball bearing having a desired bearing rigidity, exhibiting durability against misalignment, and having a small rotational torque from the viewpoint of improving fuel efficiency is often used. In this double row angular contact ball bearing, a plurality of balls are interposed between a fixed ring and a rotating ring, and a predetermined contact angle is given to the balls so as to contact the fixed ring and the rotating ring.

  Further, the wheel bearing device has a structure called a first generation in which a wheel bearing composed of a double row angular ball bearing or the like is fitted between a knuckle and a hub wheel constituting a suspension device. Second generation structure in which the body mounting flange or wheel mounting flange is directly formed on the outer periphery of the member (outer ring), or the third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub ring, or the hub It is roughly divided into a fourth generation structure in which inner rolling surfaces are directly formed on the outer circumference of the outer joint member of the wheel and the constant velocity universal joint.

  In recent years, in such a wheel bearing device, there is a strong demand for improvement in so-called NVH, as well as improvement in durability and cost reduction, as well as noise (NOISE), vibration (VIBRATION), unpleasant noise (HARSHNESS). By the way, the conventional wheel bearing 50 used for the wheel bearing device includes, as shown in FIG. 5, for example, an outer member 51 in which an outer race surface 51a having a double-row arcuate cross section is formed on the inner periphery. A pair of inner rings 52, 52 having an inner raceway 52a having an arcuate cross-section facing the outer raceway 51a of the double row on the outer periphery, and a double row ball 53 accommodated between the two raceways. The bearing portion of each row is composed of a double row angular ball bearing having a contact angle α. A seal 54 is attached to seal the annular space formed between the outer member 51 and the inner ring 52, leakage of lubricating grease sealed inside the bearing, rainwater, dust, etc. from the outside into the bearing. Is prevented from entering.

  The shoulders 55 and 56 having higher shoulders in the cross sections of the rolling surfaces 51a and 52a smoothly follow the arcuate curves a and b constituting the rolling surfaces 51a and 52a, respectively, and the curves a and b. Auxiliary rolling surfaces 55a and 56a having a cross-sectional shape composed of a curved line or a straight line with a smaller curvature are provided. Further, chamfered portions 55b and 56b having an arcuate cross-sectional shape following the edges of the auxiliary rolling surfaces 55a and 56a are formed.

  According to the wheel bearing device having such a configuration, since the auxiliary rolling surfaces 55a and 56a are provided, the contact ellipse of the ball 53 is caused to roll when the bearing is subjected to a large moment load and the contact angle α is increased. The surfaces 51a and 52a protrude from the auxiliary rolling surfaces 55a and 56a. However, since these auxiliary rolling surfaces 55a and 56a have a cross-sectional shape that continues smoothly from the curves a and b constituting the cross sections of the rolling surfaces 51a and 52a and have a straight cross-sectional shape, the contact ellipse is auxiliary rolling. Edge load (excessive stress) does not occur even if the surfaces 55a and 56a protrude.

  Further, since the auxiliary rolling surfaces 55a and 56a are straight, even if the inner diameter of the outer member 51 is set to be small or the outer diameter of the inner ring 52 is set to be large, the rolling surfaces 51a of the arcuate curves a and b are set. The inclination is larger than the surface obtained by extending 52a as it is, and a certain degree of inclination angle can be formed. For this reason, when the auxiliary rolling surfaces 55a and 56a are ground, the processing is not performed on the side surface of the grindstone, and an increase in the processing time of the grinding can be avoided.

  Further, since the chamfered portions 55b and 56b having a circular arc shape following the edges of the auxiliary rolling surfaces 55a and 56a are formed on the respective rolling surfaces 51a and 52a, the edge load of the contact ellipse is further alleviated. (For example, refer to Patent Document 1).

JP 2004-52784 A

  In this type of wheel bearing device, when an excessive load is input from the wheel by running on the curb during driving of the vehicle, the contact ellipse of the ball 53 rides on the shoulder, and an indentation is formed on the shoulder and an abnormal noise is generated. There is a case. To solve the problem of indentation, it is necessary to increase the shoulder height. However, if the shoulder height is increased, problems such as an increase in weight and a decrease in workability occur, which is preferable because it causes an increase in cost. Absent. As for the inner ring 52, when the shoulder height is increased, the cross-sectional height of the seal 54 is reduced correspondingly, and sufficient sealing performance cannot be ensured. Here, shoulder climbing means that, for example, when a large moment load is applied to the bearing, the contact ellipse generated at the contact portion between the ball 53 and the outer rolling surface 51a is from the inner diameter and the corner portion of the outer rolling surface 51a. This refers to the phenomenon of protrusion and edge loading.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wheel bearing device that prevents occurrence of an edge load of a contact ellipse of a ball and improves acoustic characteristics and life.

  In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel attachment for attaching a wheel to one end. From a hub ring integrally having a flange and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring fitted to the small-diameter step portion of the hub ring or an outer joint member of a constant velocity universal joint And an inner member in which a double row inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery, and is accommodated in a freely rollable manner between the both rolling surfaces via a cage. A ball bearing device comprising: a double row of ball rows; and a seal mounted in an opening of an annular space formed between the outer member and the inner member. The diameter is set to be the same, and the large moment of the double row inner rolling surface Shoulder height of the inner rolling surface on the side where the heavy is loaded is set to be larger than the shoulder height of the other inner raceway surface.

  As described above, in the wheel bearing device of the first generation to the fourth generation structure constituted by the double row angular ball bearings, the ball diameters of the double row ball rows are set to be the same, and the double row inner rolling Among the surfaces, the shoulder height of the inner rolling surface on the side where a large moment load is applied is set to be larger than the shoulder height of the other inner rolling surface, so that the pressure resistance improves and the ball Thus, it is possible to provide a wheel bearing device that prevents an edge load from being generated by preventing the contact ellipse from climbing over the shoulder and improving acoustic characteristics and life.

  Preferably, as in the invention according to claim 2, the shoulder height of the outer rolling surface on the side where a large moment load is applied among the outer rolling surfaces of the double row is the other outer rolling surface. If it is set to be larger than the shoulder height of the ball, it is possible to prevent the contact ellipse of the ball from climbing over the shoulder and prevent the occurrence of an edge load, thereby improving the acoustic characteristics and life.

  Further, as in the invention according to claim 3, if the pitch circle diameter of the outer side ball row is set larger than the pitch circle diameter of the inner side ball row among the double row ball rows, By increasing the diameter of the pitch circle, the outer wall becomes thicker and the strength can be increased, and the working point distance of the double row of ball rows can be increased, improving the overall bearing rigidity and life. it can.

  Moreover, like invention of Claim 4, among the inner side rolling surfaces of the said double row, the shoulder height of the outer side inner side rolling surface is set larger than the shoulder height of the inner side inner side rolling surface. If the shoulder height of the outer rolling surface on the outer side of the double row outer rolling surfaces is set to be greater than the shoulder height of the outer rolling surface on the inner side, the strength on the outer side -The rigidity is increased, the pressure resistance is improved, the shoulder ride is prevented, and the acoustic characteristics and the life can be improved.

  Further, as in the invention according to claim 5, if the number of balls of the outer side ball row is set larger than the number of balls of the inner side ball row, The basic load rating of the outer ball array can be increased to improve rigidity and bearing fatigue life.

  Further, as in the invention described in claim 6, if the shoulder height is set in a range of 0.35 to 0.50 with respect to the ball diameter of the double row ball row, the pressure dent resistance is reduced. As well as improving, it is possible to reliably prevent the shoulder from climbing up.

  In the invention according to claim 7, the shoulder height of the one inner rolling surface is set in a range of 0.45 to 0.50 with respect to the ball diameter of the double row ball row. The shoulder height of the other inner rolling surface is set in a range of 0.40 to 0.45 with respect to the ball diameter.

  In the invention according to claim 8, the shoulder height of the one outer rolling surface is set in a range of 0.40 to 0.45 with respect to the ball diameter of the double row ball row. The shoulder height of the other outer rolling surface is set in the range of 0.35 to 0.40 with respect to the ball diameter.

  Further, as in the invention according to claim 9, the corner portion of the shoulder portion of the inner rolling surface is rounded into an arc shape having a radius of curvature of R0.15 to 2.0, and the inner rolling surface. May be formed at the same time by a grinding wheel of a total type that forms and continuously and smoothly formed from the inner rolling surface. Further, as in the invention described in claim 10, the corners of the shoulders of the outer rolling surfaces of the double row are rounded into an arc shape having a radius of curvature of R0.15 to 2.0, and It may be formed simultaneously by a general grinding wheel that forms the outer rolling surface of the row, and may be formed smoothly and continuously from the outer rolling surface. As a result, the pressure resistance is further improved and the shoulder contact ellipse of the ball is prevented from climbing to prevent the occurrence of an edge load, thereby improving the acoustic characteristics and life.

  The wheel bearing device according to the present invention integrally has an outer member integrally formed with a double row outer rolling surface on the inner periphery, and a wheel mounting flange for mounting the wheel on one end, and on the outer periphery. A hub ring formed with a small-diameter step portion extending in the axial direction, and an outer joint member of at least one inner ring or a constant velocity universal joint fitted to the small-diameter step portion of the hub ring, the outer periphery of the double row on the outer periphery An inner member in which a double row inner rolling surface facing the rolling surface is formed, a double row ball row accommodated between the both rolling surfaces via a cage, and the outer row In a wheel bearing device including a seal mounted in an opening of an annular space formed between a side member and an inner member, the ball diameters of the double row ball rows are set to be the same, Of the double-row inner rolling surfaces, the inner rolling surface on the side where a large moment load is applied. Since the shoulder height of the surface is set to be larger than the shoulder height of the other inner rolling surface, the pressure resistance is improved and the shoulder contact ellipse of the ball is prevented from climbing to prevent edge loading. Thus, it is possible to provide a wheel bearing device with improved acoustic characteristics and life.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is a principal part enlarged view which shows the ball | bowl row | line | column of the outer side of FIG. It is a principal part enlarged view which shows the ball | bowl row | line | column of the inner side of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view which shows the conventional wheel bearing.

  A vehicle body mounting flange that is integrally attached to the knuckle on the outer periphery, an outer member that is integrally formed with an outer rolling surface of a double row on the inner periphery, and a wheel mounting flange for mounting a wheel on one end are integrated. A hub wheel having an inner rolling surface facing one of the outer rolling surfaces of the double row on the outer periphery, and a cylindrical small diameter step portion extending in an axial direction from the inner rolling surface, and the hub An inner member made of an inner ring press-fitted into a small diameter step portion of the ring and having an inner rolling surface facing the other of the outer rolling surfaces of the double row on the outer periphery, and a cage between the rolling surfaces. In a wheel bearing device comprising: a double row of ball rows accommodated so as to be freely rollable via; and a seal attached to an opening of an annular space formed between the outer member and the inner member The ball diameters of the double row ball rows are set to be the same, and the two rolling surfaces of the double row are opposite to each other. The shoulder height of the rolling surface on the side where a large moment load is applied is set larger than the shoulder height of the other rolling surface, and the corner of the shoulder portion of the rolling surface has a radius of curvature. It is rounded into a circular arc consisting of R0.15 to 2.0, and is formed smoothly and continuously at the same time by a general grinding wheel that forms the rolling surface.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, FIG. 2 is an enlarged view of a main part showing a ball row on the outer side of FIG. 1, and FIG. It is a principal part enlarged view which shows the ball row | line | column on the inner side. In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outer side (left side in FIG. 1), and the side closer to the center is referred to as the inner side (right side in FIG. 1).

  This wheel bearing device is for a driving wheel called a third generation, and includes an inner member 3 including a hub wheel 1 and an inner ring 2 press-fitted and fixed to the hub wheel 1, and the inner member 3. The outer member 5 inserted through the double-row balls 4 and 4 is mainly configured.

  The hub wheel 1 has a wheel mounting flange 6 for mounting a wheel (not shown) at an end portion on the outer side, one (outer side) arcuate inner rolling surface 1a on the outer periphery, and the inner rolling surface. A cylindrical small diameter step portion 1b extending in the axial direction from the running surface 1a is formed, and a serration (or spline) 1c for torque transmission is formed on the inner periphery. On the other hand, the inner ring 2 is formed with the other (inner side) arcuate inner rolling surface 2a on the outer periphery, and is press-fitted into the small-diameter step portion 1b of the hub ring 1 through a predetermined squeeze. In addition, hub bolts 6a for fastening a wheel and a brake rotor (not shown) are planted in the wheel mounting flange 6 at equal intervals in the circumferential direction.

  The hub wheel 1 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner raceway surface 1a and the base portion 6b on the inner side of the wheel mounting flange 6 to the small diameter step portion 1b. Thus, the surface hardness is set to a range of 58 to 64 HRC by induction hardening. As a result, the hub wheel 1 has sufficient mechanical strength against the rotational bending load applied to the wheel mounting flange 6 and the fretting resistance of the small-diameter stepped portion 1b serving as the fitting portion of the inner ring 2 is improved. Improves durability. Further, the inner ring 2 and the ball 4 are made of high carbon chrome bearing steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core part by quenching.

  The outer member 5 integrally has a vehicle body mounting flange 5c to be attached to a knuckle (not shown) on the outer periphery, and has a double row facing the inner rolling surfaces 1a, 2a of the inner member 3 on the inner periphery. Arc-shaped outer rolling surfaces 5a and 5b are integrally formed. Similar to the hub wheel 1, the outer member 5 is formed of medium and high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and at least the double row outer raceway surfaces 5a and 5b are surface hardened by induction hardening. Is cured in the range of 58 to 64 HRC. Then, double-row balls 4 and 4 are accommodated between the rolling surfaces of the outer member 5 and the inner member 3 via a cage 7 so as to roll freely. In addition, seals 8 and 9 are attached to the opening of the annular space formed between the outer member 5 and the inner member 3, and leakage of lubricating grease sealed inside the bearing and rainwater and dust from the outside. Etc. are prevented from entering the inside of the bearing.

  The outer-side seal 8 is made of a core metal 10 press-fitted into the inner periphery of the outer-side end of the outer member 5 and is integrally joined to the core metal 10 by vulcanization adhesion or the like, and is made of an elastic member such as nitrile rubber. It is composed of an integrated seal composed of the seal member 11. The seal member 11 includes a pair of side lips 11a and 11b extending obliquely outward in the radial direction and a radial lip 11c extending inclined toward the bearing inward side. The pair of side lips 11a and 11b are slidably contacted with a base portion 6b of a wheel mounting flange 6 having an arc-shaped cross section through a predetermined axial shimiro, and the radial lip 11c has a predetermined diameter on the outer diameter of the base portion 6b. It is slidably contacted through a direction shimoshiro.

  Further, the inner seal 9 constitutes a so-called pack seal composed of an annular seal plate 12 and a slinger 13 having a substantially L-shaped cross section. The seal plate 12 includes a cored bar 14 that is press-fitted into the inner periphery of the inner side end of the outer member 5, and a seal member 15 that is integrally vulcanized and bonded to the cored bar 14. The seal member 15 includes a side lip 15a extending obliquely outward in the radial direction, a grease lip 15b and an intermediate lip 15c formed in a bifurcated shape.

  On the other hand, the slinger 13 includes a cylindrical portion 13a that is press-fitted into the outer diameter of the inner ring 2, and a standing plate portion 13b that extends radially outward from the cylindrical portion 13a. The side lip 15a of the seal member 15 is in sliding contact with the upright plate portion 13b, and the grease lip 15b and the intermediate lip 15c are in sliding contact with the cylindrical portion 13a.

  In this embodiment, the pitch circle diameter PCDo of the four rows of balls on the outer side and the pitch circle diameter PCDi of the four rows of balls on the inner side are set to the same diameter (PCDo = PCDi), and the balls of the four rows of balls on the outer side The diameter do is set to the same diameter (do = di) as the ball diameter di of the four rows of balls on the inner side, and the number of balls Zo of the four rows of balls on the outer side is the same as the number of balls Zi of the four rows of balls on the inner side (Zo = Zi).

  Here, in the present embodiment, the shoulder heights Ho1 and Hi1 of the inner rolling surface 1a of the hub wheel 1 and the inner rolling surface 2a of the inner ring 2 are set differently. That is, the shoulder height Ho1 of the outer side inner rolling surface 1a is set in a range of Ho1 / do = 0.45 to 0.50 with respect to the ball diameter do of the four rows of balls, and the inner side inner side. The shoulder height Hi1 of the rolling surface 2a is set in a range of Hi1 / di = 0.40-0.45 with respect to the ball diameter di of the four rows of balls (Ho1 ≧ Hi1).

  As a result, the basic load rating of the four rows of balls on the outer side and the four rows of balls on the inner side is the same, but the thickness of the hub wheel 1 can be substantially increased to increase strength, and a large moment can be achieved. Even when a load is applied, the pressure resistance of the outer four rows of balls is improved as compared to the inner four rows of balls, and the shoulders of the contact ellipses of the balls 4 are prevented from climbing on the shoulder, thereby preventing the occurrence of edge load. It is possible to provide a wheel bearing device with improved characteristics and life.

  Further, among the double row outer rolling surfaces 5a and 5b of the outer member 5, the shoulder height Ho2 of the outer rolling surface 5a on the outer side and the shoulder height Hi2 of the outer rolling surface 5b on the inner side are different. Is set. That is, the shoulder height Ho2 of the outer rolling surface 5a on the outer side is set in a range of Ho2 / do = 0.40 to 0.45 with respect to the ball diameter do of the four rows of balls, and the outer side on the inner side. The shoulder height Hi2 of the rolling surface 5b is set to a range of Hi2 / di = 0.35 to 0.40 with respect to the ball diameter di of the four rows of balls (Ho2 ≧ Hi2).

  As a result, the thickness of the outer member 5 can be set effectively thin, the weight and the cost can be reduced, and the inner side can be reduced even when a large moment load is applied, as with the inner member 3 side. Compared to the four rows of balls, the pressure resistance of the four rows of balls on the outer side is improved, and the shoulder of the contact ellipse of the balls 4 is prevented from climbing to prevent the occurrence of edge load, thereby improving the acoustic characteristics and life. it can.

  Furthermore, in this embodiment, as shown in an enlarged view in FIG. 2, the corner A of the shoulder portion of the inner raceway surface 1a of the hub wheel 1 has an arc shape with a radius of curvature r of R0.15 to 2.0. It is rounded. The corner A is simultaneously formed by a general grinding wheel that forms the inner rolling surface 1a, and is formed smoothly and continuously from the inner rolling surface 1a.

  Moreover, the corner | angular part B of the shoulder part of the outer side outer side rolling surface 5a in the outer member 5 is rounded by the circular arc shape whose curvature radius r consists of R0.15-2.0. The corners B are simultaneously formed by a general grinding wheel that forms the double-row outer rolling surfaces 5a and 5b, and are formed smoothly and continuously from the outer rolling surface 5a.

  Further, as shown in an enlarged view in FIG. 3, the corner C of the shoulder portion of the inner raceway surface 2a in the inner ring 2 is rounded into an arc shape having a radius of curvature r of R0.15 to 2.0, and the total type Are formed smoothly and continuously with the inner rolling surface 1a, and the corner D of the shoulder of the inner side outer rolling surface 5b has a radius of curvature r of R0.15 to 2.0. It is rounded into a circular arc, and is formed smoothly and continuously at the same time as the double row outer rolling surfaces 5a, 5b by a grinding wheel of the total type.

  In this way, these corners A to D are rounded into an arc shape by a general grinding wheel, and are smoothly formed continuously with each rolling surface, and the curvature radius r is set to R 0.15 to 2.0. As a result, the pressure resistance can be further improved, and the contact ellipse of the ball 4 can be prevented from climbing on the shoulder, thereby improving the acoustic characteristics and life. If the radius of curvature r of these corners A to D exceeds R2.0, the substantial shoulder height decreases and there is a concern that the shoulder rides up, and if the radius of curvature r is 0.15 or less, Not only is molding difficult, but the above-described effects cannot be expected, which is not preferable.

  FIG. 4 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention. This embodiment basically differs from the first embodiment only in the pitch circle diameter of the double row of ball rows, and is the same as the above-described embodiment in the same part or the same part or part having the same function. Are denoted by the same reference numerals, and detailed description thereof is omitted.

  This wheel bearing device is for a driving wheel called a third generation, and includes an inner member 17 including a hub wheel 16 and an inner ring 2 press-fitted and fixed to the hub wheel 16, and the inner member 17. The outer member 18 inserted through the double-row balls 4 and 4 is mainly configured.

  The hub wheel 16 includes a wheel mounting flange 6 at an outer end portion, an outer arc-shaped inner rolling surface 16a on an outer periphery, and a cylindrical small-diameter step portion 1b extending in an axial direction from the inner rolling surface 16a. And a serration 1c for torque transmission is formed on the inner periphery. The hub wheel 16 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner rolling surface 16a and the inner side base portion 6b of the wheel mounting flange 6 to the small diameter step portion 1b. As a result, the surface hardness is set to a range of 58 to 64 HRC by induction hardening.

  The outer member 18 has a vehicle body mounting flange 5c integrally on the outer periphery, and double-row arc-shaped outer rolling surfaces 18a, 5b facing the inner rolling surfaces 16a, 2a of the inner member 17 on the inner periphery. It is integrally formed. Similar to the hub wheel 16, the outer member 18 is made of medium and high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and at least the double row outer raceway surfaces 18a and 5b are surface hardened by induction hardening. Is cured in the range of 58 to 64 HRC. Then, double-row balls 4 and 4 are accommodated between the rolling surfaces of the outer member 18 and the inner member 17 via the cage 7 so as to roll freely. Seals 8 and 9 are attached to the opening of the annular space formed between the outer member 18 and the inner member 17, and leakage of lubricating grease sealed inside the bearing and rainwater and dust from the outside. Etc. are prevented from entering the inside of the bearing.

  In the present embodiment, the pitch circle diameter PCDo of the four rows of balls on the outer side is set to a larger diameter (PCDo> PCDi) than the pitch circle diameter PCDi of the four rows of balls on the inner side, and the four rows of balls on the outer side are arranged. The ball diameter do is set to the same diameter (do = di) as the ball diameter di of the four rows of balls on the inner side, and the number of balls Zo of the four rows of balls on the outer side is larger than the number of balls Zi of the four rows of balls on the inner side. (Zo ≧ Zi) is set. As a result, the basic load rating of the outer four rows of balls is increased with respect to the inner four rows of balls, thereby improving the rigidity and bearing fatigue life. Further, the diameter of the pitch circle diameter PCDo is increased to increase the thickness of the hub wheel 16 and increase the strength. In addition, the working point distance of the four rows of balls is increased, and the overall bearing rigidity and life are increased. Can be further improved.

  Here, the shoulder height Ho1 of the inner side rolling surface 16a on the outer side is set in a range of Ho1 / do = 0.45 to 0.50 with respect to the outer diameter do of the ball 4, and the inner side on the inner side The shoulder height Hi1 of the rolling surface 2a is set to a range of Hi1 / di = 0.40-0.45 with respect to the outer diameter di of the ball 4 (Ho1 ≧ Hi1).

  As a result, the thickness of the hub wheel 16 can be further increased and the strength can be increased, and even when a large moment load is applied, the pressure resistance of the outer four rows of balls is higher than that of the inner four rows of balls. In addition to the improvement, it is possible to prevent the shoulder of the contact ellipse of the ball 4 from climbing and to prevent the occurrence of edge loading, thereby improving the acoustic characteristics and the life.

  Of the double row outer rolling surfaces 18 a and 5 b of the outer member 18, the shoulder height Ho2 of the outer rolling surface 18 a on the outer side is Ho 2 / do = 0. It is set in the range of 40 to 0.45, and the shoulder height Hi2 of the inner side outer rolling surface 5b is in the range of Hi2 / di = 0.35 to 0.40 with respect to the outer diameter di of the ball 4. (Ho2 ≧ Hi2).

  As a result, the thickness of the outer member 18 can be set effectively thin, the weight can be reduced and the cost can be reduced. Compared to the four rows of balls, the pressure resistance of the four rows of balls on the outer side is improved, the shoulder of the contact ellipse of the balls 4 is prevented from climbing, and the generation of edge load is prevented, thereby improving the acoustic characteristics and life. it can.

  Further, in the present embodiment, the corners A to D of the shoulders of the respective inner rolling surfaces 16a, 2a, 18a, and 5b are rounded into an arc shape having a curvature radius r of R0.15 to 2.0, It is formed smoothly and continuously at the same time by a total type grinding wheel forming the inner rolling surfaces 16a, 2a, 18a and 5b.

  In this way, these corners A to D are rounded into an arc shape by a general grinding wheel, and are smoothly formed continuously with each rolling surface, and the curvature radius r is set to R 0.15 to 2.0. Therefore, the pressure resistance can be further improved, the contact ellipse of the ball 4 can be prevented from climbing on the shoulder, the occurrence of edge loading can be prevented, and the acoustic characteristics and life can be improved.

  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. Of course, the scope of the present invention is indicated 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.

  The wheel bearing according to the present invention can be applied to a wheel bearing device having a first to fourth generation structure regardless of whether it is for driving wheels or driven wheels.

1, 16 Hub wheel 1a, 2a, 16a Inner rolling surface 1b Small diameter step 1c Serration 2 Inner ring 3, 17 Inner member 4 Ball 5, 18 Outer member 5a, 18a Outer outer rolling surface 5b Inner side Outer rolling surface 5c Car body mounting flange 6 Wheel mounting flange 6a Hub bolt 6b Base 7 Cage 8, 21 Outer side seal 9 Inner side seal 10, 14 Core metal 11, 15 Seal members 11a, 11b, 15a Side lip 11c Radial Lip 12 Seal plate 13 Slinger 13a Cylindrical portion 13b Standing plate portion 50 Wheel bearing device 51 Outer member 51a Outer rolling surface 52 Inner ring 52a Inner rolling surface 53 Ball 54 Seal 55, 56 Shoulder edge portions 55a, 56a Auxiliary Rolling surface 55b, 56b Chamfered portion a, b Curved portion A, B, C, D, E Corner portion of shoulder portion di Bolt on inner side Ball diameter do of outer row ball diameter of outer side ball row Hi1, Hi2, Ho1, Ho2 Shoulder height PCDi pitch circle diameter of inner side ball row PCDo pitch circle diameter Zi of outer side ball row Inner side ball row Number of balls Zo Number of balls in the outer row of balls α Contact angle

Claims (10)

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end thereof and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring fitted to the small-diameter step portion of the hub ring Or an inner member formed of an outer joint member of a constant velocity universal joint and having a double-row inner rolling surface facing the double-row outer rolling surface on the outer periphery;
A double row of ball rows accommodated in a freely rollable manner between the rolling surfaces via a cage;
In a wheel bearing device comprising a seal mounted in an opening of an annular space formed between the outer member and the inner member,
The ball diameters of the double row ball rows are set to be the same, and the shoulder height of the inner raceway surface on the side where a large moment load is applied among the inner raceway surfaces of the double row is the other inner side. A wheel bearing device characterized in that it is set to be larger than the shoulder height of the rolling surface.   The shoulder height of the outer rolling surface on the side where a large moment load is applied among the outer rolling surfaces of the double row is set larger than the shoulder height of the other outer rolling surface. The wheel bearing device described.   3. The wheel bearing device according to claim 1, wherein a pitch circle diameter of the outer side ball row is set larger than a pitch circle diameter of the inner side ball row of the double row ball row. 4.   Among the inner surface of the double row, the shoulder height of the inner side rolling surface on the outer side is set larger than the shoulder height of the inner side rolling surface on the inner side, and the outer rolling surface of the double row 4. The wheel bearing device according to claim 3, wherein a shoulder height of the outer rolling surface on the outer side is set larger than a shoulder height of the outer rolling surface on the inner side.   5. The wheel bearing device according to claim 3, wherein the number of balls in the outer-side ball row is set larger than the number of balls in the inner-side ball row.   The wheel bearing device according to any one of claims 1 to 5, wherein the shoulder height is set in a range of 0.35 to 0.50 with respect to a ball diameter of the double row of ball rows.   The shoulder height of the one inner rolling surface is set in a range of 0.45 to 0.50 with respect to the ball diameter of the double row ball row, and the shoulder height of the other inner rolling surface is set. Is set to the range of 0.40-0.45 with respect to the said ball diameter, The wheel bearing apparatus in any one of the Claims 1 thru | or 6 is set.   The shoulder height of the one outer rolling surface is set in a range of 0.40 to 0.45 with respect to the ball diameter of the double row ball row, and the shoulder height of the other outer rolling surface is set. Is set to a range of 0.35 to 0.40 with respect to the ball diameter.   The corner portion of the shoulder portion of the inner rolling surface is rounded into an arc shape having a radius of curvature of R0.15 to 2.0, and simultaneously formed by a general grinding wheel that forms the inner rolling surface, The wheel bearing device according to any one of claims 1 to 8, wherein the wheel bearing device is formed smoothly and continuously from the inner rolling surface.   The corner grinding of the shoulder portion of the outer surface of the double row is rounded into an arc shape having a radius of curvature of R0.15 to 2.0, and the overall grinding that forms the outer surface of the double row is formed. The wheel bearing device according to any one of claims 1 to 9, wherein the wheel bearing device is formed simultaneously with a grindstone and is formed smoothly and continuously from the outer rolling surface.

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