JP5097479B2 - Wheel bearing and wheel bearing device provided with the same - Google Patents

Description

  The present invention relates to a wheel bearing for rotatably supporting a wheel of a vehicle such as an automobile, and more particularly, to a wheel bearing for reducing the weight, size and cost, and improving the durability of the bearing. The present invention relates to a wheel bearing device provided.

  2. Description of the Related Art Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like supports a hub wheel for mounting a wheel rotatably via a double row rolling bearing, and includes a drive wheel and a driven wheel. For structural reasons, an inner ring rotation method is generally used for driving wheels, and both an inner ring rotation method and an outer member rotation method are generally used for driven wheels. This 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, and an outer member. 2nd generation structure with body mounting flange or wheel mounting flange formed directly on the outer periphery of the wheel, 3rd generation structure with one inner rolling surface formed directly on the outer periphery of the hub wheel, or constant speed with the hub wheel It is roughly classified into a fourth generation structure in which the inner rolling surface is directly formed on the outer periphery of the outer joint member of the universal joint.

  Conventionally, an angular ball bearing having a structure in which an inner ring and an outer ring (outer member) are formed by pressing from a steel plate is known. For example, the angular ball bearing 50 shown in FIG. 6 is used in a magnetic hard disk drive or the like, but the outer ring 51 and the pair of inner rings 52 and 53 are formed from a stainless steel plate by pressing or rolling.

  The outer ring 51 is formed with an annular convex portion 51a protruding radially inward at a substantially middle portion of the inner peripheral surface, and outer rolling surfaces 51b and 51c are formed on inner peripheral surfaces on both sides of the annular convex portion 51a. Yes. The outer ring 51 has an outer peripheral surface fitted into a hole in the housing 54, and a flange 51 d formed at one end is brought into contact with the end surface of the housing 54 to perform axial positioning. An annular recess 51e is formed on the outer peripheral surface of the outer ring 51 by the annular protrusion 51a. The annular recess 51e is filled with an adhesive, and the outer ring 51 is fixed to the hole of the housing 54.

  On the other hand, the inner rings 52 and 53 are respectively fitted inside the double row outer raceway surfaces 51b and 51c of the outer ring 51 from both sides in the axial direction. Curved shoulder portions 52a and 53a are formed on the outer circumferences of the outer ends in the axial direction of the inner rings 52 and 53, and inner rolling surfaces 52b and 53b are formed on the curved shoulder portions 52a and 53a. The double rows of balls 56, 56 are arranged between the inner rolling surfaces 52b, 53b and the outer rolling surfaces 51b, 51c of the outer ring 51, and are retained by the cages 57, 57 for each row. Is retained.

  On the inner peripheral surfaces of the inner rings 52 and 53, fitting portions 52c and 53c that are fitted into the shaft member 55 with clearance are formed. After the inner rings 52, 53 are fitted into the shaft member 55 in the axial direction, a cylindrical weight 59 having a constant weight is placed on the curved shoulder 52 a of one inner ring 52, and the weight of the weight 59 The other inner ring 53 is pressed via the inner ring 52, the ball 56, the outer ring 51, and the ball 56, and the curved shoulder portion 53 a is fitted until it comes into contact with the flange portion 55 a of the shaft member 55. Thereby, an appropriate preload is set for the angular ball bearing 50.

When this gap fitting is completed, the adhesive 60 is filled in the gap between the curved shoulder portion 52a of the one inner ring 52 and the shaft member 55, and this adhesive 60 prevents the one inner ring 52 from being fitted off. The flange portion 55a of the shaft member 55 prevents the other inner ring 53 from being fitted off.
Japanese Utility Model Publication No. 6-1835

  When this type of angular contact ball bearing made of a press is used as a wheel bearing, the size of the ball 56 or the PCD (pitch circle diameter) of the ball 56 depends on the radial load or moment load applied during vehicle axle load or turning. ) Etc. are set, and the optimum shape is determined. However, since the outer ring 51 or the inner rings 52 and 53 are formed from a steel plate by pressing or rolling, the thickness is substantially uniform. However, depending on the shape of the outer ring 51 or the inner rings 52 and 53, there may be a portion where the thickness is reduced.

  In particular, in the outer ring 51, when a moment load is applied, the contact ellipse of the ball 56 rides up and comes off the outer rolling surface 51 b, so-called shoulder riding occurs, and edge load may occur in the shoulder A. At the time of rolling processing, the center portion of the outer ring 51 is recessed to fill the shoulder portion A with material, and the shoulder height from the groove bottom of the outer rolling surface 51b to the annular convex portion 51a is ensured to an appropriate height. However, in this case, depending on the size of the radius of curvature R of the connecting portion B from the outer diameter to the annular recess 51e, not only the wall thickness is reduced, but there is a possibility that the shoulder A may crack. . As a result, the rigidity of the outer ring 51 may be reduced and durability may be impaired. Here, the edge load is an excessive stress concentration generated at a corner or the like, and refers to an event that becomes one of the factors of early peeling.

  In addition, in assembling this type of angular ball bearing 50, a ball 56 is mounted on the retainer 57 in advance, and this ball cassette is inserted into the double row outer raceway 51a of the outer ring 51, and finally the inner rings 52, 53 are inserted. Is inserted from both sides of the outer ring 51. At this time, since the counter part is not formed on the outer ring 51 and the inner rings 52, 53, the ball cassette and the inner rings 52, 53 once assembled in the assembly process are used. As a result, the assembly man-hours increase due to reassembly and the like, and the assembly process may become complicated.

  The present invention has been made in view of such circumstances, and it is intended to provide a wheel bearing and a wheel bearing device including the wheel bearing that are intended to improve the durability of the bearing and simplify the assembly. It is aimed.

  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 arc-shaped outer rolling surface is integrally formed on the inner periphery, and the double-row on the outer periphery. A pair of inner rings formed with an arcuate inner rolling surface facing the outer rolling surface, a double row of balls accommodated between the inner ring and both rolling surfaces of the outer member, and the balls A wheel bearing that includes a cage that is rotatably accommodated, and a small-diameter side end face of the inner ring abuts in a butted state to form a back-to-back type double-row angular ball bearing. It is composed of a snap-on type formed from resin by injection molding, and the ball is held so as to roll freely so that it does not fall off in the radial direction, and the outer member and inner ring are formed from pipe material by plastic working. At least facing the shoulder of the outer rolling surface Counter portion is formed by plastic working site that.

  As described above, in the wheel bearing constituted by the back-to-back type double row angular contact ball bearing, the cage is constituted by a snap-on type formed by injection molding from synthetic resin, and the ball does not fall off in the radial direction. The outer member and the inner ring are formed from the pipe material by plastic working, and at least a counter portion is formed by plastic working at a portion facing the shoulder portion of the outer rolling surface. Therefore, the ball cassette once assembled in the assembly process can be prevented from dropping from the outer member, and the assembly can be simplified. Here, the snap-on type refers to a snap-type cage in which a ball is attached and detached by the elasticity of synthetic resin.

  Preferably, as in the invention described in claim 2, if the inner diameter of the counter portion is set smaller than the circumscribed circle diameter of the ball in the ball cassette in which the ball is held in the cage, It is possible to reliably prevent the ball cassette from falling off the outer member.

  According to a third aspect of the present invention, a counter portion is formed by plastic working at a portion facing the shoulder portion of the inner rolling surface, and the outer diameter of the counter portion is such that the ball is placed on the cage. If the inner diameter of the held ball cassette is set to be larger than the inscribed circle diameter of the ball, the inner ring once assembled in the assembly process is prevented from falling off in the axial direction, thereby further simplifying the assembly. be able to.

  Further, as in the invention described in claim 4, if the counter portion is ground by a grindstone simultaneously with the side rolling surface after heat treatment, deformation due to heat treatment is removed to reduce the inner diameter of the counter portion. A wheel bearing that can be finished with higher accuracy, suppresses the occurrence of scratches due to the passage of balls during assembly, and has high reliability in quality can be provided.

  Further, as in the invention according to claim 5, an annular concave portion is formed by denting the axial central portion of the outer diameter of the outer member, and the annular convex portion is formed in a flat shape on the inner periphery, If the connecting portion between the outer diameter and the annular recess is formed in an arc shape having a predetermined radius of curvature, and this portion is set to a substantially uniform thickness, it prevents the shoulder from cracking, and Further, it is possible to prevent the contact ellipse of the ball from climbing over the shoulder portion when the turning moment is applied and the occurrence of an edge load, thereby improving the durability of the bearing.

  Preferably, as in the invention described in claim 6, the radius of curvature R of the joint portion is set to be in a range of R = 1.5 to 1.8 Rw when the radius of the ball is Rw. In this case, the thickness is not reduced and the rigidity is not lowered, and the thickness is increased and the workability of the plastic working is not lowered.

  Further, as in the invention described in claim 7, both end faces of the outer member and the large-diameter side end face of the inner ring are turned after plastic working, and after heat treatment, both the rolling faces and the outer face If the outer diameter of the member and the inner diameter of the inner ring and the end face on the small diameter side are formed to a predetermined size and accuracy by grinding, productivity can be improved, yield can be reduced, and cost can be reduced. Bearing accuracy equivalent to that of a machined bearing can be ensured.

  Further, as in the invention according to claim 8, if the outer member and the inner ring are formed by cold rolling from the pipe material, the thickness can be made substantially uniform, and the shape, The dimensions can be ensured with a predetermined accuracy.

  Further, the invention according to claim 9 of the present invention is a hub wheel having a wheel mounting flange integrally formed at one end and a small-diameter stepped portion extending in the axial direction from the wheel mounting flange via the shoulder. And a wheel bearing according to any one of claims 1 to 8, which is press-fitted into a small-diameter step portion of the hub wheel via a predetermined scissors, and an outer joint member of a constant velocity universal joint is provided on the hub wheel. The inner ring is fitted through a serration, and the pair of inner rings are sandwiched between a shoulder portion of the hub wheel and a shoulder portion of the outer joint member, and a predetermined bearing preload is applied.

  Thus, in the wheel bearing device of the first generation structure, a hub wheel having a wheel mounting flange integrally formed at one end and a small-diameter step portion extending in the axial direction from the wheel mounting flange via the shoulder is formed. And a wheel bearing according to any one of claims 1 to 4, which is press-fitted into the small-diameter step portion of the hub wheel via a predetermined shimiro, and the outer joint member of the constant velocity universal joint serrated on the hub wheel. And the pair of inner rings are sandwiched between the shoulder part of the hub wheel and the shoulder part of the outer joint member, and a predetermined bearing preload is applied. Rolling fatigue life is improved.

  The wheel bearing according to the present invention includes an outer member in which a double-row arc-shaped outer rolling surface is integrally formed on the inner periphery, and an arc-shaped inner surface facing the outer-rolling surface of the double-row on the outer periphery. A pair of inner rings formed with rolling surfaces; a double row of balls accommodated between the inner races and the rolling surfaces of the outer member; and a cage for accommodating these balls in a freely rolling manner. In the wheel bearing that constitutes a back-to-back type double row angular contact ball bearing in which the small-diameter side end faces of the inner ring collide in a butted state, the retainer is a snap-on type formed by injection molding from a synthetic resin The outer member and the inner ring are formed from a pipe material by plastic working so that the ball does not fall off in the radial direction, and at least on the shoulder of the outer rolling surface Counter part for plastic working at the opposite part Because it is formed Ri, it is possible to simplify the assembly to prevent the once assembled ball cassette assembly process off from the outer member.

  A pair of outer members in which a double-row arc-shaped outer rolling surface is integrally formed on the inner periphery, and an arc-shaped inner rolling surface facing the outer-rolling surface of the double-row is formed on the outer periphery. An inner ring, a double row of balls accommodated between the rolling surfaces of the inner ring and the outer member, and a cage for accommodating these balls in a freely rolling manner, with the end faces on the small diameter side of the inner ring butting each other In a wheel bearing that forms a back-to-back type double row angular contact ball bearing by abutting in a state, the cage is a snap-on type formed by injection molding from a synthetic resin, and the ball is in the radial direction. The outer member and the inner ring are formed by a cold rolling process from the pipe material, and the outer diameter of the outer member is recessed in the center in the axial direction. Concave part is formed, and annular convex part is flat on the inner periphery Jo to be formed, the counter portion at a site opposed to the shoulder portion of at least the outer raceway surfaces are formed by plastic working concurrently with said outer raceway surfaces.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
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 showing the wheel bearing of FIG. 1, and FIG. 3 (a) is an outward view of FIG. FIG. 4B is an enlarged view of a main part of FIG. 4A, FIG. 4A is a vertical cross-sectional view of the inner ring of FIG. 2, and FIG. 4B is an essential part of FIG. 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 has a first generation structure, and includes a hub wheel 1 and a wheel bearing 2 attached to the hub wheel 1. A constant velocity universal joint 3 is fitted into the hub wheel 1 so as to be able to transmit torque, and the hub wheel 1 and the constant velocity universal joint 3 are detachably integrated via a fixing nut 4.

  The hub wheel 1 integrally has a wheel mounting flange 5 for mounting a wheel (not shown) at one end portion on the outer side, and a cylinder extending in the axial direction from the wheel mounting flange 5 to the outer periphery via a shoulder portion 1a. A small diameter step portion 1b is formed, and a serration (or spline) 1c for torque transmission is formed on the inner periphery. 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 remains as it is after forging. In addition, in order to increase the fatigue strength with respect to the bending strength, the tempering treatment may be performed after forging, or the surface hardness is set in the range of 58 to 64 HRC by induction hardening from the shoulder portion 1a to the small diameter step portion 1b. You may do it.

  The wheel bearing 2 is fitted into a knuckle 6, and as shown in an enlarged view in FIG. 2, an outer member (outer ring) 7 in which double-row arc-shaped outer rolling surfaces 7a and 7a are formed on the inner periphery. A pair of inner rings 8 and 8 having arcuate inner rolling surfaces 8a and 8a formed on the outer periphery and facing these double-row outer rolling surfaces 7a and 7a, and cages 9 and 9 between both rolling surfaces. And the double-row balls 10 and 10 accommodated so as to be freely rollable via each other, and the seals 11 attached to both ends of the outer member 7. The cage 9 is formed of a synthetic resin such as PA (polyamide) 66 by injection molding, and is configured as a so-called snap-on type that holds the ball 10 in the concave spherical pocket 9a, and the ball 10 falls off in the radial direction. Is preventing. The end faces 8b, 8b on the small diameter side (front side) of the inner rings 8, 8 are abutted in a butted state to constitute a so-called back-to-back type double row angular ball bearing.

  The seal 11 is formed of an elastomer such as nitrile rubber, which is integrally joined to the metal core 11a by vulcanization adhesion or the like, and a metal core 11a fitted to the cylindrical portion 13 formed at both ends of the outer member 7. It consists of a seal member 11b and has a pair of radial lips. In addition, leakage of grease sealed in the bearing and foreign matter such as rainwater and dust from the outside are prevented from entering the bearing. The seal 11 is not limited to the illustrated integrated seal, but although not shown, an annular seal plate and a slinger mounted on the outer diameter of the cylindrical portion 13 of the outer member 7 and the outer ring 8 and arranged opposite to each other. A so-called pack seal may be used.

  As shown in FIG. 1, the constant velocity universal joint 3 includes an outer joint member 15, a joint inner ring 16, a cage 17, and a torque transmission ball 18. The outer joint member 15 integrally includes a cup-shaped mouth portion 19, a shoulder portion 20 that is a bottom portion of the mouth portion 19, and a shaft portion 21 that extends from the shoulder portion 20 in the axial direction. A serration 21a that engages with the serration 1c of the hub wheel 1 is formed on the outer periphery of the shaft portion 21, and a male screw 21b is formed at the end of the serration 21a. The outer joint member 15 is fitted into the hub wheel 1 via the serrations 1c and 21a until the shoulder 20 abuts the large end surface of the inner ring 8, and the pair of inner rings 8 and 8 is the shoulder 1a of the hub ring 1. The outer joint member 15 is press-fitted into the small-diameter step portion 1b of the hub wheel 1 through a predetermined squeeze while being sandwiched between the shoulder portions 20 of the outer joint member 15. Further, a predetermined bearing preload is applied to the male screw 21b by tightening the fixing nut 4 with a predetermined tightening torque. As a result, the bearing rigidity is increased and the rolling fatigue life of the bearing is improved.

  Here, the outer member 7 and the inner ring 8 are formed by pressing or cold rolling (hereinafter referred to as plastic working) a pipe material made of bearing steel such as SUJ2 or carburized steel such as SCr420 or SCM415. . Then, SUJ2 is hardened to a surface hardness of 50 to 64 HRC by submerged or induction hardening, and carburized steel is carburized and quenched. Other examples of the material of the outer member 7 and the inner ring 8 include carburized steel such as SCM440, cold rolled steel (JIS standard SPCC system, etc.), and carbon steel such as S45C.

  On the other hand, in the case of cold rolled steel or carbon steel, at least the outer member 7 has double row outer rolling surfaces 7a and 7a, and the inner ring 8 has inner rolling surface 8a having a surface hardness by induction hardening. Is hardened in the range of 50 to 64 HRC to improve the rolling fatigue life. These rolling surfaces 7a and 8a are formed with predetermined dimensions and accuracy by grinding. After that, superfinishing is performed as necessary.

Next, the configuration of the outer member 7 and the inner ring 8 will be described in detail with reference to FIGS. 3 and 4.
As shown in FIG. 3 (a), the outer member 7 includes an annular projection 12 projecting radially inward from the pipe material, which is a raw material, on both sides of the annular projection 12 by plastic working. Double-row arc-shaped outer rolling surfaces 7 a and 7 a are formed, and cylindrical portions 13 and 13 that are fitting portions of the seal 11 are formed at both ends. The cylindrical portion 13 including the double-row outer rolling surfaces 7a and 7a is formed with a predetermined size and accuracy by grinding after plastic working. Thereby, the precision and sealing performance equivalent to the conventional bearing can be ensured. Note that both end surfaces where burrs are generated by plastic working are turned after machining. Moreover, a grinding process is given as needed.

  Here, in order to appropriately secure the shoulder height of the annular convex portion 12 from the outer rolling surface 7a, the inner diameter of the annular convex portion 12 is formed in a flat shape during plastic processing of the outer member 7, and the outer side The central portion of the member 7 in the axial direction is recessed to form an annular recess 23 so that the shoulder 22 is filled with the material.

  Here, in this embodiment, the radius of curvature R of the connecting portion 24 between the outer diameter 7b of the outer member 7 and the annular recess 23 is set within a predetermined range. Specifically, when the radius of the ball 10 is Rw, the curvature radius R is set to be in a range of R = 1.5 to 1.8 Rw. As a result, the thickness of this portion can be formed substantially evenly, and cracks can be prevented from occurring in the shoulder portion 22, and the contact ellipse of the ball 10 rides on the shoulder portion 22 when a turning moment is applied, thereby causing edge loading. It is possible to provide a wheel bearing 2 that can secure an appropriate shoulder height that can be prevented from being generated, and improve the durability of the bearing. Here, “substantially equal” means that the thickness of the pipe material before molding is uniform, and the thickness of the shape obtained as a result of molding without any plastic flow other than the purpose of forming the arc portion of the connecting portion 24 as well. This means that a state where the thickness of the connecting portion 24 is slightly reduced or increased due to the displacement of the thickness of the material when forming the arc of the connecting portion 24 is included.

  When the radius of curvature R of the connecting portion 24 is smaller than 1.5 times the radius Rw of the ball 10, the thickness is reduced and the rigidity is lowered, so that it cannot withstand the stress at the time of turning moment load. If it exceeds 1.8 times, not only will the wall thickness increase and the workability of plastic working will decrease, but the shape will not greatly differ from conventional forged products, and it will not contribute to light weight and compactness in general. is there.

  Further, as shown in an enlarged view in (b), a counter portion 25 is formed simultaneously with the outer rolling surface 7a by plastic working at a portion facing the shoulder portion 22 of the outer rolling surface 7a. The inner diameter Dc of the counter portion 25 is set to be smaller by 2δo than the groove bottom diameter Do (Dc = Do−2δo). That is, the diameter is set smaller than the circumscribed circle diameter Db of the ball 10 in the ball cassette so that the ball cassette does not fall off from the outer member 7 (Dc <Db). Here, the circumscribed circle diameter Db of the ball 10 also takes into account the amount of movement of the ball 10 held in the pocket of the cage 9 so as to move radially inward within the pocket. Thereby, it is possible to reliably prevent the ball cassette once assembled in the assembling process from falling off the outer member 7, thereby simplifying the assembly.

  Furthermore, you may grind the counter part 25 of the outer member 7 with a total type grindstone simultaneously with the outer side rolling surface 7a after heat processing. As a result, deformation due to heat treatment can be eliminated and the inner diameter Dc of the counter portion 25 can be finished with higher accuracy, the occurrence of scratches caused by the passage of the ball 10 during assembly can be suppressed, and the quality of the wheel can be highly reliable. A bearing 2 can be provided.

  On the other hand, as shown in FIG. 4 (a), the inner ring 8 has an arcuate inner raceway surface 8a on the outer periphery by a plastic working from a pipe material, and a shoulder extending in the axial direction from the inner raceway surface 8a. A portion 14 is formed. Here, the shoulder portion 14 becomes a seal land portion of the seal 11 and is ground at the same time as the inner rolling surface 8a after plastic working, and is formed with a predetermined size and accuracy. Thereby, the precision and sealing performance equivalent to the conventional bearing can be ensured. As with the outer member 7, both end surfaces where burrs are generated by plastic working are turned after machining. Moreover, a grinding process is given as needed.

  Further, as shown in an enlarged view in (b), a counter portion 26 is formed simultaneously with the inner rolling surface 8a by plastic working at a portion facing the shoulder portion 14 of the inner rolling surface 8a. The outer diameter dc of the counter portion 26 is set to be larger by 2δi than the groove bottom diameter di (dc = di + 2δi). That is, the inner ring 8 is set to have a larger diameter than the inscribed circle diameter db of the ball 10 in the ball cassette (dc> db) so that the inner ring 8 does not fall off. Here, the inscribed circle db of the ball 10 also takes into account the amount of movement that the ball 10 held in the pocket of the cage 9 behaves radially outward in the pocket. As a result, it is possible to reliably prevent the inner ring 8 once assembled in the assembly process from dropping off in the axial direction, thereby simplifying the assembly.

  Furthermore, as with the outer member 7, the counter portion 26 may be ground with a total-type grindstone simultaneously with the inner rolling surface 8a after the heat treatment. As a result, the deformation due to the heat treatment can be removed and the outer diameter dc of the counter portion 26 can be finished with higher accuracy, the occurrence of scratches caused by the passage of the ball 10 during assembly can be suppressed, and the reliability can be improved. .

  Here, the outer diameter 7b of the outer member 7 that becomes the fitting surface of the knuckle 6 and the hub wheel 1, the inner diameter 8c of the inner ring 8, and the small-diameter side end surface 8b of the inner ring 8 that becomes the butting surface are formed by grinding. You may do it. Thereby, the bearing accuracy equivalent to the conventional forged and machined bearing can be ensured.

  FIG. 5 is a longitudinal sectional view showing a second embodiment of the wheel bearing according to the present invention. This embodiment basically differs from the above-described embodiment only in the configuration of the inner ring and the seal, and other detailed description is given with the same reference numerals for the same parts, parts or parts having the same function. Omitted.

  The wheel bearing 27 includes an outer member 7 having double-row arc-shaped outer rolling surfaces 7a, 7a formed on the inner periphery, and an arc shape facing the double-row outer rolling surfaces 7a, 7a on the outer periphery. A pair of inner rings 28, 28 formed with inner rolling surfaces 8 a, 8 a, and double row balls 10, 10 accommodated so as to roll between the rolling surfaces via the cages 9, 9, Seals 29 and 29 are provided at both ends of the outer member 7. The end faces 8b, 8b on the small diameter side of the inner rings 28, 28 are abutted in a butted state to constitute a so-called back-to-back type double row angular ball bearing.

  The seal 29 includes a core metal 30 fitted to the cylindrical portion 13 of the outer member 7 and a seal member 31 integrally joined to the core metal 30 by vulcanization adhesion or the like and made of an elastomer such as nitrile rubber. And a pair of side lips 31a and 31b. These side lips 31a and 31b are in elastic contact with a large-diameter end surface 28a of the inner ring 28, which will be described later, and leakage of grease sealed inside the bearing and foreign matters such as rainwater and dust enter the bearing from the outside. And the inner ring 28 is prevented from falling off in the axial direction.

  Although not shown, the wheel bearing 27 is press-fitted into the hub wheel via a predetermined shimiro as in the above-described embodiment, and the end surface 28a on the large diameter side of the inner ring 28 is connected to the shoulder of the outer joint member and the hub ring. A predetermined bearing preload is applied in a state in which the pair of inner rings 28 and 28 are held in contact with the shoulder.

  Here, the inner ring 28 is formed by plastic working from a pipe material made of bearing steel such as SUJ2 or carburized steel such as SCr420 or SCM415. Then, SUJ2 is hardened to a surface hardness of 50 to 64 HRC by submerged or induction hardening, and carburized steel is carburized and quenched.

  The inner ring 28 is formed with an arc-shaped inner rolling surface 8a on the outer periphery and a shoulder 32 extending radially outward from the inner rolling surface 8a. The outer diameter of the shoulder portion 32 is formed to be larger than that of the PCD, and even if a large moment load is applied to the bearing, it is possible to prevent the shoulder ride-up and improve the durability. Here, the side surface of the shoulder portion 32, that is, the end surface 28 a on the large diameter side, becomes a seal land portion of the seal 29 and is ground after plastic working. Thereby, the burr | flash which generate | occur | produced by plastic working can be removed, and a predetermined dimension, precision, and surface roughness are obtained.

  Moreover, the counter part 26 is formed simultaneously with this inner side rolling surface 8a by the plastic working in the site | part which opposes the shoulder part 32 of the inner side rolling surface 8a. Accordingly, it is possible to reliably prevent the inner ring 28 from falling off in the axial direction even during the assembly process before the seal 29 is mounted or during conveyance.

  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 of a first generation structure including a hub wheel integrally having a wheel mounting flange at one end and a pair of inner rings press-fitted into the hub wheel.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is an enlarged view which shows the wheel bearing of FIG. (A) is a longitudinal cross-sectional view which shows the outward member single-piece | unit of FIG. (B) is the principal part enlarged view of (a). (A) is a longitudinal cross-sectional view which shows the inner ring single-piece | unit of FIG. (B) is the principal part enlarged view of (a). It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing which concerns on this invention. It is a longitudinal cross-sectional view which shows the angular contact ball bearing of the structure where the conventional inner and outer ring | wheel was formed by press work.

Explanation of symbols

1 ····················· Hub wheel 1a, 14, 20, 22, 32 ... shoulder 1b ······ Small diameter Step 1c, 21a ... Serration 2, 27 ... Wheel bearing 3 ...・ ・ ・ Constant velocity universal joint 4 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Fixing nut 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange 6 ... Knuckle 7 ... Outer member 7a ... Outer rolling surface 7b ... Outer diameter 8, 28 ... Inner ring 8a ...・ ・ ・ ・ ・ Inner rolling surface 8b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ End surface 8c on the small diameter side ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ Inner diameter 9 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Retainer 9a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pocket 10 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・············ Balls 11, 29 ····························································· Cores 11b, 31 ...... Sealing member 12 ............ annular convex part 13 ............ cylindrical part 15 ...... Outer joint member 16 ... Inner joint ring 17 ... Cage 18・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Torque transmission ball 19 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Mouse part 21・ Shaft 21b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Male thread 23 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... Annular recess 24 ... Connector 25, 26 ... Counter 28a ... ...... Large-diameter end faces 31a, 31b ... side lip 50 ... angular ball bearing 51 ... ... outer ring 51a ... annular convex parts 51b, 51c ... outer rolling surface 51d ... ··········· Flange 51e ············································ ... curved shoulders 52b, 53b ... inner rolling surfaces 52c, 53c ... fitting part 54 ... ... Housing 55 ... ··········· Shaft member 55a ········································· Ball 57・ ・ ・ ・ ・ ・ ・ ・ ・ Retainer 59 ・ ・ ・ ・ ・ ・ ・ ・ Weight 60 ・ ・ ・ ・ ・ ・ ・ ・Adhesive A ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shoulder B ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Connection part dc ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ Outer diameter Dc of the counter part of the inner ring ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner diameter di of the counter part of the outer member ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... Groove bottom diameter Do on the inner rolling surface ......... Groove bottom diameter R on the outer rolling surface ... .... Radius of curvature Rw ... Ball radius δi ... Projection of counter part of inner ring The amount of protrusion of the counter portion of the amount .delta.o ··············· outer member

Claims (9)

An outer member in which a double-row arc-shaped outer rolling surface is integrally formed on the inner periphery;
A pair of inner rings each having an arcuate inner rolling surface facing the double row outer rolling surface on the outer periphery;
A double row of balls accommodated between both rolling surfaces of the inner ring and the outer member;
In a wheel bearing comprising a cage that accommodates these balls in a rollable manner, and a small-diameter side end surface of the inner ring abuts in a butted state to constitute a back-to-back type double row angular ball bearing,
The cage is composed of a snap-on type formed by injection molding from a synthetic resin, and the ball is held so as to roll freely so as not to fall off in the radial direction.
The wheel bearing according to claim 1, wherein the outer member and the inner ring are formed from a pipe material by plastic working, and at least a counter portion is formed by plastic working at a portion facing the shoulder portion of the outer rolling surface.   The wheel bearing according to claim 1, wherein an inner diameter of the counter portion is set to be smaller than a circumscribed circle diameter of the ball in a ball cassette in which the ball is held by the cage.   A counter portion is formed by plastic working at a portion facing the shoulder portion of the inner rolling surface, and the outer diameter of the counter portion is an inscribed circle diameter of the ball in the ball cassette in which the ball is held by the cage. The wheel bearing according to claim 1 or 2, wherein the wheel bearing is set to have a larger diameter.   The wheel bearing according to any one of claims 1 to 3, wherein the counter portion is ground by a total-type grindstone simultaneously with the rolling surface after heat treatment.   An annular recess is formed by denting the axially central portion of the outer diameter of the outer member, the annular protrusion is formed in a flat shape on the inner periphery, and the joint between the outer diameter and the annular recess has a predetermined curvature. The wheel bearing according to any one of claims 1 to 4, wherein the wheel bearing is formed in a circular arc shape having a radius, and the portion is set to have a substantially uniform thickness.   The wheel bearing according to claim 5, wherein a curvature radius R of the joint portion is set to be in a range of R = 1.5 to 1.8 Rw, where Rw is a radius of the ball.   Both end faces of the outer member and the large-diameter side end face of the inner ring are turned after plastic working, and after heat treatment, both the rolling surfaces, the outer diameter of the outer member, the inner diameter of the inner ring, and the small-diameter side end face The wheel bearing according to claim 1, wherein the wheel bearing is formed with a predetermined size and accuracy by grinding.   The wheel bearing according to claim 1, wherein the outer member and the inner ring are formed by cold rolling from a pipe material.   A hub wheel integrally having a wheel mounting flange at one end and having a small-diameter step portion extending in the axial direction from the wheel mounting flange via a shoulder portion, and a predetermined squeeze through a small-diameter step portion of the hub wheel The wheel bearing according to any one of claims 1 to 8, wherein the outer joint member of a constant velocity universal joint is fitted into the hub wheel via a serration, and the pair of inner rings are the hub. A wheel bearing device characterized by being sandwiched between a shoulder portion of a ring and a shoulder portion of the outer joint member and given a predetermined bearing preload.

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