JP2011106531A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel preventing occurrence of a ball score and improving acoustic characteristics and the lifetime. <P>SOLUTION: In the bearing device for a wheel formed of a double row angular contact ball bearing in which counter parts 10 with a smaller diameter than a diameter of the groove bottom of double row outer rolling surfaces 5a, 5a of an external member 5 are formed in the vicinity of the groove bottom, predetermined hardened layers 11 are formed in the double row outer rolling surfaces 5a, 5a of the external member 5 by induction hardening, edges of the hardened layers 11 stop in the vicinity of the counter parts 10, the counter parts 10 are made non-quenched parts, the hardness difference against the surface hardness of the outer rolling surface 5a is set 30 HRC or above, therefore occurrence of a hitting score in balls 4 is prevented even when the balls 4 repeatedly contact the counter parts 10 while vibration is applied during transportation and the like, and the acoustic characteristics and lifetime can be improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like, and more particularly to a wheel bearing device that prevents the occurrence of ball hitting and the like and improves acoustic characteristics and life.

  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. It is roughly divided into the 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 wheel. Has been.

  In recent years, in such a wheel bearing device, there is a strong demand for improvement in so-called NVH, not to mention improvement in durability and cost reduction, but noise (NOISE), vibration (VIBRATION), unpleasant sound (HARSHNESS). For example, as shown in FIG. 15, the conventional wheel bearing device includes a hub wheel 51, an inner ring 52, an outer ring 53, and double-row balls 54 and 54. The hub wheel 51 integrally has a wheel mounting flange 55 for mounting a wheel (not shown) at one end thereof, and a small diameter step extending in the axial direction from the wheel mounting flange 55 to the outer periphery via the inner rolling surface 51a. A portion 51b is formed. Further, hub bolts 56 for fixing the wheels are planted at the circumferentially equidistant positions of the wheel mounting flanges 55.

  A pair of inner rings 52, 52 having an inner rolling surface 52 a formed on the outer periphery is press-fitted into the small-diameter step portion 51 b of the hub wheel 51. Then, the pair of inner rings 52, 52 are removed from the hub wheel 51 in the axial direction by the crimped portion 51c formed by plastically deforming the end portion of the small diameter step portion 51b of the hub wheel 51 radially outward. It is preventing.

  The outer ring 53 integrally has a vehicle body mounting flange 53b for mounting to a suspension device (not shown), and double row outer rolling surfaces 53a, 53a are formed on the inner periphery. Between the double-row outer rolling surfaces 53a and 53a and the inner rolling surfaces 51a and 52a opposed to the double-row outer rolling surfaces 53a and 53a, double-row balls 54 and 54 are movably accommodated.

  The hub wheel 51 is integrally formed by forging a carbon steel material having a carbon content of 0.40 to 0.80% by weight, and a portion indicated by cross hatching, that is, a wheel mounting flange 55. The surface is hardened by induction quenching from the base portion to the inner rolling surface 51a and the small diameter step portion 51b. The caulking portion 51c is made as raw material surface hardness after forging. On the other hand, the inner ring 52 is made of high carbon steel such as high carbon chromium bearing steel such as SUJ2, and is hardened and hardened to the core.

  As a result, a wheel bearing device having sufficient durability at low cost can be realized, the preload can be maintained at an appropriate value, and the cost can be reduced by reducing the number of parts, parts processing, and assembly man-hours (for example, Patent Document 1). reference.).

JP-A-11-129703

  In this type of wheel bearing device, a groove is formed in the vicinity of the groove bottom of each rolling surface so that the ball 54 does not fall off from the rolling surfaces 51a, 52a, 53a of the inner ring 52 and the outer ring 53 including the hub wheel 51 after the bearing is assembled. A counter portion protruding from the bottom diameter is formed. However, these counter units come into contact with the balls 54 at the edges during conveyance or in an assembly process at an automobile manufacturer. In particular, when an impact load is generated due to excessive vibration or the like, there is a possibility that the ball 54 in contact with the hardened counter portion may be damaged. In addition, when the bearing is assembled, the ball 54 passes through the counter portion, so that the ball 54 may be slightly scratched. Such abrasion of the balls 54 not only deteriorates the acoustic characteristics of the bearing, but also sometimes shortens the service life.

  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 the occurrence of ball scratches 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. The hub wheel has a flange integrally 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. Inner members formed with opposing double-row inner rolling surfaces, and double-row balls accommodated between the rolling surfaces of the inner member and the outer member via a cage. A wheel bearing device in which a counter part having a diameter smaller than the groove bottom diameter is formed in the vicinity of the groove bottom part of the outer rolling surface of the double row of the outer member. A predetermined hardened layer is formed on the running surface by induction hardening, and an edge of the hardened layer is formed on the counter unit. Stops in the vicinity, the counter unit is a non-quenched portion.

  As described above, in the wheel bearing device constituted by the double row angular contact ball bearing and having a counter part having a diameter smaller than the groove bottom diameter in the vicinity of the groove bottom part of the outer side rolling surface of the double row of the outer member, A predetermined hardened layer is formed by induction hardening on the outer raceway of the double row of members, and the edge of this hardened layer stops near the counter part, and the counter part is an unquenched part. When vibration is applied in the middle, it is possible to prevent the ball from being scratched even if the ball repeatedly contacts the counter portion, and to improve the acoustic characteristics and life.

  Preferably, as in the invention described in claim 2, if the hardness difference between the surface hardness of the counter portion and the outer rolling surface is set to 30 HRC or more, even if the ball repeatedly contacts the counter portion, It is possible to reliably prevent the occurrence of scratches.

  Further, as in the invention according to claim 3, the hardened layer of the outer rolling surface is limited to a range in which a contact ellipse is formed by contact between the outer rolling surface and the ball when a load is applied. For example, the ball can be prevented from being scratched, the acoustic characteristics and the life can be improved, and the work life of the induction hardening can be shortened while ensuring the bearing life, thereby reducing the cost. be able to.

  Further, as in the invention according to claim 4, if the hardened layer is continuously formed over the inner diameter portion between the outer rolling surfaces of the double row, the ball is damaged. In addition, the acoustic characteristics and life can be improved, and sufficient rigidity can be ensured even when an excessive moment load is applied to the outer member.

  Further, as in the invention described in claim 5, the hub wheel has one inner rolling surface on the outer periphery and a counter portion having a diameter larger than the groove bottom diameter in the vicinity of the groove bottom portion of the inner rolling surface. In addition, if the inner rolling surface is formed with a predetermined hardened layer by induction hardening, the edge of the hardened layer stops in the vicinity of the counter part, and the counter part is an unquenched part, At least the outer counter portion of the outer member can be eliminated, and the inner diameter of the end portion can be formed in a substantially straight shape from the groove bottom portion of the outer rolling surface, so that the weight of the outer member can be reduced.

  Further, as in the invention described in claim 6, a counter portion having a diameter larger than the groove bottom diameter is formed in the vicinity of the groove bottom portion of the inner raceway surface of the inner ring, and the outer diameter of the counter portion is the outer diameter. In a state where the ball is stored in the groove bottom of the outer rolling surface of the member, the diameter is set to be larger by a predetermined squeeze margin than the inscribed circle diameter of the ball, and the counter on the inner side of the outer member If the portion is abolished and the inner diameter of the end portion is formed in a substantially straight shape from the groove bottom portion of the outer rolling surface, it is possible to prevent the ball from being damaged.

  According to a seventh aspect of the present invention, the counter portion is formed in a cylindrical shape extending in the axial direction from the inner rolling surface, and the corner portion thereof is rounded into an arc shape and formed smoothly and continuously. In this case, even when the ball passes through the counter portion of the inner ring at the time of assembly, it is possible to prevent the ball from being scratched.

  Preferably, as in the invention described in claim 8, if the counter portion is ground simultaneously with the inner rolling surface by a total grinding wheel formed in a predetermined shape and size, A smooth counter part can be formed, the occurrence of burrs, etc. can be reliably prevented, and the counter part has an outer diameter within a predetermined standard value so that the click margin of the counter part is within a predetermined tolerance range. The shape and dimensions of the counter portion can be accurately and smoothly formed continuously.

  Further, as in the ninth aspect of the invention, the counter portion is not formed in the vicinity of the groove bottom portion of the outer rolling surface of the outer member, and an annular shape is formed at a position away from the groove bottom portion by a predetermined distance. If a recess is formed and an annular convex portion is formed on the outer periphery of the end portion of the cage and is engaged with the recess of the outer member, the ball cassette is dropped from the outer rolling surface during assembly. In addition, it is possible to prevent the ball from being damaged even when vibration is applied during transportation, and to improve acoustic characteristics and life.

  Further, as in the invention described in claim 10, one inner rolling surface is formed on the outer periphery of the hub wheel, and an annular recess is formed at a position away from the groove bottom of the inner rolling surface by a predetermined distance. And the counter part is not formed in the vicinity of the groove bottom of the outer rolling surface of the outer member, and an annular convex part is formed on the inner periphery of the end of the cage, When engaged in the recess, the ball cassette can be prevented from falling off the inner rolling surface during assembly, and the ball can be prevented from being damaged even when vibration is applied during transportation. The acoustic characteristics and life can be improved.

  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 double-row inner rolling surface comprising a hub wheel formed with a small-diameter step portion extending in the axial direction and at least one inner ring press-fitted into the small-diameter step portion and facing the outer surface of the double row on the outer periphery. And a double row of balls accommodated between the rolling surfaces of the inner member and the outer member via a cage so as to be freely rollable. In a wheel bearing device in which a counter portion having a diameter smaller than the groove bottom diameter is formed in the vicinity of the groove bottom of the double row outer rolling surface, predetermined hardening is performed by induction hardening on the outer rolling surface of the double row of the outer member. A layer is formed, and the edge of the hardened layer stops near the counter part, and the counter Part there is a non-quenched portion. Since the material surface hardness is an unquenched part with a hardness of 28 HRC or less, when vibration is applied during transportation, etc., the ball is prevented from being scratched even if the ball repeatedly contacts this counter part. The lifetime can be improved.

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 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 of FIG. It is a longitudinal cross-sectional view which shows 3rd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view of FIG. It is a longitudinal cross-sectional view which shows 4th Embodiment of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view of FIG. It is a longitudinal cross-sectional view which shows 5th Embodiment of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view of FIG. It is a longitudinal cross-sectional view which shows 6th Embodiment of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view of FIG. It is a longitudinal cross-sectional view which shows 7th Embodiment of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view of FIG. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

  An outer member integrally having a vehicle body mounting flange to be attached to the vehicle body on the outer periphery, a double row outer rolling surface formed integrally on the inner periphery, and a wheel mounting flange for mounting a wheel on one end A hub wheel integrally formed with an inner rolling surface facing one of the outer rolling surfaces of the double row on the outer periphery, a small-diameter step portion extending in the axial direction from the inner rolling surface, and the small-diameter step An inner member comprising an inner ring that is press-fitted into the outer periphery and formed with an inner rolling surface facing the other of the double row outer rolling surfaces on the outer periphery, and both rolling surfaces of the inner member and the outer member And a double row ball accommodated in a rollable manner via a cage, and a counter portion having a smaller diameter than the groove bottom diameter is formed in the vicinity of the groove bottom portion of the double row outer rolling surface of the outer member. In the wheel bearing device thus obtained, the outer row rolling surface of the outer member is placed by induction hardening. The hardened layer is formed, the edge of the hardened layer stops near the counter part, the counter part is an unquenched part, and the hardness difference from the surface hardness of the outer rolling surface is set to 30 HRC or more. Has been.

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, and FIG. 2 is an enlarged view of a main part of FIG. 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 5b 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 5a 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 the double row outer raceway surfaces 5a and 5a are surface hardened by induction hardening. Curing treatment is performed 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. In addition, although the 3rd generation structure comprised by the double row angular contact ball bearing was illustrated here, this invention is not restricted to this, A 1st generation or a 2nd generation structure may be sufficient.

  Here, as shown in an enlarged view in FIG. 2, the outer member 5 is a counter portion having a diameter smaller than the groove bottom diameter at a position away from the groove bottom portions of the double row outer rolling surfaces 5a, 5a. 10 is formed. The inner diameter of the counter unit 10 is such that the ball 4 is held in the cage 7 and the circumscribed circle diameter of the ball 4 is reduced, so that the ball 4 does not fall out of the cage 7. The range is set so as not to drop off from 10.

  In this embodiment, the hardened layer 11 (indicated by cross-hatching in the figure) is formed on each of the outer rolling surfaces 5 a and 5 a by induction hardening. It stops in the vicinity, and the counter unit 10 is an unquenched portion having a material surface hardness of 28 HRC or less. And the hardness difference with the surface hardness 58-64HRC of the outer side rolling surface 5a is set to 30 HRC or more. As a result, when vibration is applied during transportation or the like, the ball 4 can be prevented from being damaged even if the ball 4 is repeatedly contacted with the counter portion 10, and the acoustic characteristics and life can be improved.

  FIG. 3 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention, and FIG. 4 is an enlarged view of a main part of FIG. This embodiment is basically the same as the first embodiment described above (FIG. 1) except that the configuration of a part of the outer member is different, and has the same components and the same functions as the other embodiments described above. Parts 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 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 12 inserted through the double-row balls 4 and 4 is mainly configured.

  The outer member 12 has a vehicle body mounting flange 5b integrally on the outer periphery, and double-row arc-shaped outer rolling surfaces 5a, 5a are integrally formed on the inner periphery. The outer member 12 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the groove bottom is located at a predetermined distance from the groove bottoms of the double row outer rolling surfaces 5a and 5a. A counter portion 10 having a smaller diameter than the diameter is formed. The double row outer rolling surfaces 5a and 5a are hardened by induction hardening to a surface hardness of 58 to 64 HRC.

  Here, in the present embodiment, as shown in an enlarged view in FIG. 4, the hardened layer 13 (shown by cross-hatching in the figure) of each outer rolling surface 5a, 5a is preferably in the range from the shoulder to the groove bottom. Is formed in a contact angle α30 to 40 °, limited to a range covered by a contact ellipse due to contact between the outer rolling surface 5a and the ball 4 when a load is applied. Thereby, when vibration is applied during transportation or the like, it is possible to prevent the ball 4 from being damaged even if the ball 4 repeatedly comes into contact with the counter unit 10, and to improve the acoustic characteristics and life, The work time of induction hardening can be shortened while ensuring the bearing life, and the cost can be reduced.

  FIG. 5 is a longitudinal sectional view showing a third embodiment of the wheel bearing device according to the present invention, and FIG. 6 is an enlarged view of a main part of FIG. This embodiment is basically the same as the first embodiment described above (FIG. 1) except that the configuration of a part of the outer member is different, and has the same components and the same functions as the other embodiments described above. Parts 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 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 14 inserted through the double-row balls 4 and 4 is mainly configured.

  The outer member 14 has a vehicle body mounting flange 5b integrally on the outer periphery, and double-row arc-shaped outer rolling surfaces 5a, 5a are integrally formed on the inner periphery. The outer member 14 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the groove bottom is located at a predetermined distance from the groove bottoms of the double row outer rolling surfaces 5a and 5a. A counter portion 10 having a smaller diameter than the diameter is formed. The double row outer rolling surfaces 5a and 5a are hardened by induction hardening to a surface hardness of 58 to 64 HRC.

  Here, in the present embodiment, as shown in an enlarged view in FIG. 6, the hardened layer 16 (cross-hatched in the drawing) is continuously formed over the inner diameter portion 15 between the adjacent outer rolling surfaces 5 a and 5 a. The edge of the hardened layer 16 stops in the vicinity of the counter unit 10, and the counter unit 10 is an unquenched portion having a material surface hardness of 28HRC or less. Thereby, when vibration is applied during transportation or the like, it is possible to prevent the ball 4 from being damaged even if the ball 4 repeatedly comes into contact with the counter unit 10, and to improve the acoustic characteristics and life, Even when an excessive moment load is applied to the outer member 14, sufficient rigidity can be ensured.

  FIG. 7 is a longitudinal sectional view showing a fourth embodiment of the wheel bearing device according to the present invention, and FIG. 8 is an enlarged view of a main part of FIG. In addition, the same code | symbol is attached | subjected to the component same site | part or the site | part which has the same function as embodiment mentioned above, and detailed description is abbreviate | omitted.

  This wheel bearing device is for a driving wheel called a third generation, and includes an inner member 19 including a hub wheel 17 and an inner ring 18 press-fitted and fixed to the hub wheel 17, and the inner member 19. The outer member 20 inserted through the double-row balls 4 and 4 is mainly configured.

  The hub wheel 17 has a wheel mounting flange 6 at an end on the outer side, one arc-shaped inner rolling surface 17a on the outer periphery, and a cylindrical small-diameter step portion extending in the axial direction from the inner rolling surface 17a. 1b is formed, and a serration (or spline) 1c for torque transmission is formed on the inner periphery. On the other hand, the inner ring 18 is formed with the other arc-shaped inner rolling surface 18a on the outer periphery, and is press-fitted into the small-diameter step portion 1b of the hub wheel 17 through a predetermined squeeze.

  The inner side base portion 6b of the wheel mounting flange 6 is formed in a curved surface having a circular arc cross section, and the seal lip of the outer side seal 8 is slidably contacted with the base portion 6b. A counter portion 21 having a diameter slightly larger than the groove bottom diameter is formed in the vicinity of the groove bottom portion of the inner rolling surface 17a. The counter portion 21 is formed in a cylindrical shape extending in the axial direction from the inner rolling surface 17a, and the corner portion thereof is rounded into an arc shape and is formed smoothly and continuously. The outer diameter of the counter portion 21 is set to be larger than the inscribed circle diameter of the ball 4 by a predetermined knitting margin in a state where the ball 4 is housed in the groove bottom of the outer rolling surface 20a of the outer member 20. ing.

  In the present embodiment, the hub wheel 17 is made of medium-high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and as shown in an enlarged view in FIG. 8, the base 6b on the inner side of the wheel mounting flange 6. Predetermined hardened layers 22 and 23 (indicated by cross-hatching in the figure) having a surface hardness in the range of 58 to 64 HRC by induction hardening over the inner rolling surface 17a from the shoulder 17b to the small diameter step portion 1b. Is formed. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 6, and the fretting resistance of the small-diameter step portion 1 b serving as the fitting portion of the inner ring 18 is improved. Improves durability.

  Here, the edge of the outer hardened layer 22 stops in the vicinity of the counter portion 21, and the counter portion 21 is an unquenched portion having a material surface hardness of 28 HRC or less. Thereby, when vibration is applied during transportation or the like, it is possible to prevent the ball 4 from being damaged even if the ball 4 repeatedly contacts the counter unit 21, and to improve the acoustic characteristics and life, Even when the ball 4 passes through the counter portion 21 during the assembly of the bearing, it is possible to prevent the ball 4 from being scratched.

  The inner ring 18 is made of a high carbon chrome bearing steel such as SUJ2, and is hardened in the range of 58 to 64 HRC up to the core part by quenching. Here, the inner ring 18 has a counter portion 24 having a diameter larger than the groove bottom diameter and a predetermined width in the vicinity of the groove bottom portion of the inner rolling surface 18a. The counter portion 24 is formed in a cylindrical shape extending in the axial direction from the inner rolling surface 18a, and the corner portion thereof is rounded into an arc shape and is formed smoothly and continuously. Thereby, even when the ball 4 passes through the counter portion 24 of the inner ring 18 at the time of assembly, it is possible to suppress the occurrence of scratches on the ball 4 as much as possible.

  The outer diameter of the counter portion 24 is set to a large diameter by a predetermined squeeze margin with respect to the inscribed circle diameter of the ball 4 in a state where the ball 4 is housed in the groove bottom of the outer rolling surface 20a of the outer member 20. ing. In the present embodiment, a connecting portion between the inner rolling surface 18a and the counter unit 24 is formed in an arc surface and is ground simultaneously with the inner rolling surface 18a by a general grinding wheel formed in a predetermined shape and size. ing. As a result, the outer diameter of the counter unit 24 can be regulated within a predetermined standard value so that the click margin of the counter unit 24 falls within a predetermined tolerance range, and the shape and dimensions of the counter unit 24 can be made smoothly with high accuracy. It can be formed continuously.

  The outer member 20 has a vehicle body mounting flange 5b integrally on the outer periphery, and double-row arc-shaped outer rolling surfaces 20a, 20a are integrally formed on the inner periphery. The outer member 20 is formed of medium and high carbon steel containing carbon 0.40 to 0.80 wt% such as S53C, like the hub wheel 17, and the double row outer rolling surfaces 20a and 20a have surface hardness by induction hardening. Curing treatment is performed in the range of 58 to 64 HRC.

  Here, in the present embodiment, as described above, since the counter portions 21 and 24 are formed in the vicinity of the groove bottoms of the inner rolling surfaces 17a and 18a of the hub wheel 17 and the inner ring 18, the outer member 20 is formed. Is not formed with a counter portion, and the inner diameter of the end portion is formed in a substantially straight shape from the groove bottom portion of the double row outer rolling surfaces 20a, 20a. Thereby, even if vibration is applied during transportation or the like, the ball 4 does not repeatedly come into contact with the counter portion, and it is possible to prevent the ball 4 from being damaged and to reduce the weight of the outer member 20. Can be achieved.

  FIG. 9 is a longitudinal sectional view showing a fifth embodiment of the wheel bearing device according to the present invention, and FIG. 10 is an enlarged view of a main part of FIG. This embodiment is basically the same as the first embodiment described above (FIG. 1) except that the configuration of a part of the outer member is different, and has the same components and the same functions as the other embodiments described above. Parts 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 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 25 inserted through the double-row balls 4 and 4 is mainly configured.

  The outer member 25 integrally has a vehicle body mounting flange 5b on the outer periphery, and double-row arc-shaped outer rolling surfaces 5a and 20a are integrally formed on the inner periphery. As shown in an enlarged view in FIG. 10, the outer member 25 has a groove bottom at a position away from the groove bottom of the outer rolling surface 5a on the outer side of the double row outer rolling surfaces 5a, 20a. The counter portion 10 having a smaller diameter than the diameter is formed, and no counter portion is formed in the vicinity of the groove bottom portion of the inner side outer rolling surface 20a. Here, the outer member 25 is made of medium-high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and the double row outer rolling surfaces 5a and 20a have a surface hardness of 58 to 64HRC by induction hardening. It has been cured to the extent of. Thereby, even when vibration is applied during transportation or the like, it is possible to prevent the ball 4 from being damaged and to improve acoustic characteristics and life.

  FIG. 11 is a longitudinal sectional view showing a sixth embodiment of the wheel bearing device according to the present invention, and FIG. 12 is an enlarged view of a main part of FIG. Note that this embodiment is basically the same as the first embodiment (FIG. 1) described above except that the configuration of the outer member and the outer cage is the same as the other embodiments described above. Parts having functions 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 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 26 inserted through the double-row balls 4 and 4 is mainly configured.

  The outer member 26 integrally has a vehicle body mounting flange 5b on the outer periphery, and a double-row arc-shaped outer rolling surface 20a, 5a is integrally formed on the inner periphery. As shown in an enlarged view in FIG. 12, the outer member 26 has a groove bottom at a position away from the groove bottom of the inner-side outer rolling surface 5a among the double-row outer rolling surfaces 20a, 5a. The counter portion 10 having a diameter smaller than the diameter is formed, the counter portion is not formed in the vicinity of the groove bottom portion of the outer side outer rolling surface 20a, and the annular recess is located at a predetermined distance from the groove bottom portion. 27 is formed.

  The outer member 26 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 20a and 5a have a surface hardness in the range of 58 to 64HRC by induction hardening. It has been cured. Then, double-row balls 4 and 4 are accommodated between the rolling surfaces of the outer member 26 and the inner member 3 via the cages 28 and 7 so as to roll freely.

  Here, in the present embodiment, an annular convex portion 28a is formed on the outer periphery of the end portion of the outer cage 28 of the pair of cages 28 and 7, and is engaged with the recess 27 of the outer member 26 described above. Has been. As a result, the ball cassette can be prevented from falling off the outer rolling surface 20a during assembly, and the ball 4 can be prevented from being damaged even when vibration is applied during transportation, etc. Can be improved.

  FIG. 13 is a longitudinal sectional view showing a seventh embodiment of the wheel bearing device according to the present invention, and FIG. 14 is an enlarged view of a main part of FIG. In addition, this embodiment is the same as the above-described embodiment except that the configuration of the hub wheel and the outer cage is basically the same as that of the above-described fourth embodiment (FIG. 7). The same reference numerals are given to the parts having the same, and detailed description is omitted.

  This wheel bearing device is for a driving wheel called a third generation, and includes an inner member 30 including a hub wheel 29 and an inner ring 18 press-fitted and fixed to the hub wheel 29, and the inner member 30. The outer member 20 inserted through the double-row balls 4 and 4 is mainly configured.

  The hub wheel 29 has a wheel mounting flange 6 at an end on the outer side, one arc-shaped inner rolling surface 29a on the outer periphery, and a cylindrical small-diameter stepped portion extending in the axial direction from the inner rolling surface 29a. 1b is formed, and a serration (or spline) 1c for torque transmission is formed on the inner periphery.

  As shown in an enlarged view in FIG. 14, the hub wheel 29 is not formed with a counter portion in the vicinity of the groove bottom portion of the inner rolling surface 29a, and has an annular recess 31 at a position away from the groove bottom portion by a predetermined distance. Is formed. The hub wheel 29 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and includes the inner rolling surface 29a and the base portion 6b on the inner side 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 double-row balls 4, 4 are accommodated between the rolling surfaces of the outer member 20 and the inner member 30 via the cages 32, 7 so as to roll freely.

  Here, in the present embodiment, an annular convex portion 32 a is formed on the inner periphery of the end of the outer cage 32 out of the pair of cages 32 and 7, and is engaged with the recess 31 of the hub wheel 29 described above. ing. As a result, the ball cassette can be prevented from falling off from the inner rolling surface 29a during assembly, and the ball 4 can be prevented from being damaged even when vibration is applied during transportation, etc. 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, and various modifications can be made without departing from the scope of the present invention. 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 third generation structure constituted by double-row angular ball bearings, regardless of whether for driving wheels or driven wheels.

1, 17, 29 Hub wheel 1a, 2a, 17a, 18a Inner rolling surface 1b Small diameter step 1c Serrations 2, 18 Inner ring 3, 19, 30 Inner member 4 Ball 5, 12, 14, 20, 25, 26 Outer Side member 5a, 20a Outer rolling surface 5b Car body mounting flange 6 Wheel mounting flange 6a Hub bolt 6b Base part 7, 28, 32 on the inner side of the wheel mounting flange Cage 8 Seal on the outer side 9 Seals 10, 21, 24 on the inner side Counter part 11, 13, 16, 22, 23 Hardened layer 15 Inner diameter part 17b Shoulder part 27, 31 Recess 28a, 32a Protrusion part 51 Hub wheel 51a, 52a Inner rolling surface 51b Small diameter step part 51c Clamping part 52 Inner ring 53 Outer ring 53a Outer rolling surface 53b Car body mounting flange 54 Ball 55 Wheel mounting flange 56 Hub bolt α Contact angle

Claims (10)

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
It has a wheel mounting flange for mounting a wheel at one end, and 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. An inner member formed with a double-row inner rolling surface facing the double-row outer rolling surface,
A double row of balls accommodated between the rolling surfaces of the inner member and the outer member so as to roll freely through a cage,
In the wheel bearing device in which a counter part having a diameter smaller than the groove bottom diameter is formed in the vicinity of the groove bottom part of the double row outer rolling surface of the outer member,
A predetermined hardened layer is formed by induction hardening on the outer side rolling surface of the double row of the outer member, and the edge of the hardened layer stops near the counter part, and the counter part is an unquenched part. A wheel bearing device characterized by comprising:   The wheel bearing device according to claim 1, wherein the hardness difference between the surface hardness of the counter portion and the outer rolling surface is set to 30 HRC or more.   3. The wheel bearing device according to claim 1, wherein the hardened layer of the outer rolling surface is limited to a range in which a contact ellipse is formed by contact between the outer rolling surface and the ball when a load is applied.   The wheel bearing device according to any one of claims 1 to 3, wherein the hardened layer is continuously formed over an inner diameter portion between the double row outer rolling surfaces.   The hub wheel has one inner rolling surface on the outer periphery and a counter portion having a diameter larger than the groove bottom diameter in the vicinity of the groove bottom portion of the inner rolling surface, and the inner rolling surface is formed by induction hardening. The wheel bearing device according to claim 1, wherein a predetermined hardened layer is formed, an edge of the hardened layer stops near the counter portion, and the counter portion is an unquenched portion.   A counter portion having a diameter larger than the groove bottom diameter is formed in the vicinity of the groove bottom portion of the inner raceway surface of the inner ring, and the outer diameter of the counter portion is set so that the ball is on the groove bottom portion of the outer raceway surface of the outer member. In a state of being accommodated, the diameter of the ball is inscribed with respect to the inscribed circle diameter of the ball, and the inner counter portion of the outer member is abolished, and the groove bottom portion of the outer rolling surface is eliminated. The wheel bearing device according to claim 1, wherein the inner diameter of the end portion is formed in a substantially straight shape.   The wheel bearing device according to claim 6, wherein the counter portion is formed in a cylindrical shape extending in the axial direction from the inner rolling surface, and a corner portion thereof is rounded into an arc shape and is formed smoothly and continuously. .   The wheel bearing device according to claim 6 or 7, wherein the counter portion is ground simultaneously with the inner rolling surface by a total grinding wheel formed in a predetermined shape and size.   The counter portion is not formed in the vicinity of the groove bottom portion of the outer rolling surface of the outer member, an annular recess is formed at a position away from the groove bottom portion by a predetermined distance, and the end of the cage The wheel bearing device according to claim 1, wherein an annular convex portion is formed on an outer periphery of the portion and is engaged with a recess of the outer member.   One inner rolling surface is formed on the outer periphery of the hub wheel, and an annular recess is formed at a position away from the groove bottom of the inner rolling surface by a predetermined distance. The counter part is not formed in the groove bottom part vicinity of a running surface, The cyclic | annular convex part is formed in the edge part inner periphery of the said holder | retainer, and it is engaged with the recess of the said hub ring. Wheel bearing device.

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