JP2007120594A - Wheel bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing device, having higher rigidity for suppressing damages to balls in a assembling process and extending the operating life of bearing. <P>SOLUTION: The wheel bearing device comprises a double-row angular ball bearing, having a wheel mounting flange 6 formed integrally at one end. The pitch circle diameter PCDo of the outer-side ball 3 out of double-row balls 3, 3 is set larger than the pitch circle diameter PCDi of the inner-side ball 3, the double-row balls 3 have the same outer diameter, and the number of the outer-side balls 3 is set greater than the number of the inner-side balls 3. Groove shoulder portions 17-20 and counter portions A-D of each rolling surface are formed into smooth circular shape with angular portions subjected to surface crushing, by using a formed grinding wheel for grinding them concurrently with each rolling surface after heat treatment. <P>COPYRIGHT: (C)2007,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 achieves higher rigidity and longer bearing 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. Second generation structure in which body mounting flange or wheel mounting flange is formed directly on the outer periphery of the member, third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub wheel, or hub wheel, etc. 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 speed universal joint.

  In such a wheel bearing device, conventionally, both rows of bearings have the same specification, so that they have sufficient rigidity when stationary, but the optimum rigidity is not always obtained when the vehicle turns. That is, the position of the vehicle weight when stationary is determined so that it acts on the approximate center of the double row rolling bearing, but when turning, the opposite side of the turning direction (when turning right, the vehicle Larger radial load or axial load is applied to the left axle. Therefore, at the time of turning, it is effective to increase the rigidity of the outer bearing row rather than the inner bearing row. Then, what is shown in FIG. 5 is known as a bearing device for wheels which achieved high rigidity without enlarging an apparatus.

  This wheel bearing device 50 has a vehicle body mounting flange 51c integrally attached to a knuckle (not shown) on the outer periphery, and an outer side in which double row outer rolling surfaces 51a and 51b are formed on the inner periphery. A member 51 and a wheel mounting flange 53 for mounting a wheel (not shown) at one end are integrally formed, and one inner rolling surface 52a facing the double row outer rolling surfaces 51a and 51b on the outer periphery. The hub wheel 52 formed with a small diameter step portion 52b extending in the axial direction from the inner rolling surface 52a and the small diameter step portion 52b of the hub wheel 52 are externally fitted to the double row outer rolling surface 51a, 51b. An inner member 55 composed of an inner ring 54 formed with the other inner rolling surface 54a facing each other, double rows of balls 56, 57 accommodated between both rolling surfaces, and these double rows of balls 56, 57 A retainer 58 for freely rolling It is composed of a double row angular contact ball bearing with a 9.

  The inner ring 54 is fixed in the axial direction by a caulking portion 52c formed by plastically deforming the small diameter step portion 52b of the hub wheel 52 radially outward. Seals 60 and 61 are attached to the opening of the annular space formed between the outer member 51 and the inner member 55, leakage of the lubricating grease sealed inside the bearing, and rainwater from the outside into the bearing. And dust are prevented from entering.

Here, the pitch circle diameter D1 of the outer side ball 56 is set to be larger than the pitch circle diameter D2 of the inner side ball 57. Along with this, the inner rolling surface 52a of the hub wheel 52 is expanded in diameter than the inner rolling surface 54a of the inner ring 54, and the outer rolling surface 51a on the outer side of the outer member 51 is also rolled on the inner side. The diameter is larger than that of the surface 51b. The outer side balls 56 are accommodated more than the inner side balls 57. In this way, by setting the pitch circle diameters D1 and D2 to D1> D2, the rigidity is improved not only when the vehicle is stationary but also when turning, and the life of the wheel bearing device 50 can be extended. it can.
JP 2004-108449 A

  However, in such a conventional wheel bearing device 50, the pitch circle diameter D1 of the outer side ball 56 is set larger than the pitch circle diameter D2 of the inner side ball 57. A step portion 62 is formed between the inner side rolling surface 52a on the outer side and the small-diameter step portion 52b into which the inner ring 54 is press-fitted. In other words, since a step portion 62 composed of at least a step difference (D1-D2) / 2 between the diameters of the pitch circle diameters D1 and D2 is formed, the outer rolling surface 51a on the outer side of the outer member 51 in the assembly process of the bearing. There is a possibility that the outer-side ball 56 temporarily assembled in contact with the intersection of the stepped portion 62 of the hub wheel 52 and the counter portion 63. Further, on the inner side, when the inner ring 54 is press-fitted in a state where the inner-side ball 57 is temporarily assembled on the inner-side outer rolling surface 51b of the outer member 51, the vibration of the counter portion 6457 of the inner ring 54 is caused. There was a risk that minute scratches may occur on the balls 56 and 57 due to contact when the balls 56 and 57 are assembled, as well as the corners that are generated. If the balls 56 and 57 are scratched, not only will the acoustic characteristics of the bearings deteriorate, but there is a risk of shortening the service life. Therefore, the assembly process must be carefully handled, hindering mass production. It was one of the factors.

  SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and provides a wheel bearing device that increases the rigidity of the device and suppresses the occurrence of ball scratches in the assembly process and the like, thereby extending the life of the bearing. It is intended to provide.

  In order to achieve the object, the invention according to claim 1 of the present invention is such that an outer member having a double row outer rolling surface formed on the inner periphery and an outer member facing the double row outer rolling surface on the outer periphery. An inner member in which a double row inner rolling surface is formed, and a double row ball accommodated in a freely rollable manner between the inner member and the outer member. In the bearing device, the pitch circle diameter of the outer side ball of the double row balls is set to be larger than the pitch circle diameter of the inner side ball, and a corner portion of the counter portion of each rolling surface is A configuration in which the surface is crushed and formed into a smooth arc shape is adopted.

  As described above, in the wheel bearing device constituted by the double row angular ball bearing, the pitch circle diameter of the outer side ball among the double row balls is set larger than the pitch circle diameter of the inner side ball. At the same time, the corners of the counter part of each rolling surface are crushed and formed into a smooth arc shape, which suppresses ball contact scratches during assembly and scratches caused by impact loads in the assembly process of automobile manufacturers. The acoustic characteristics of the bearing can be improved, and the reliability of product quality can be improved. Therefore, it is possible to provide a wheel bearing device in which the rigidity of the device is increased and the life of the bearing is extended.

  Preferably, as in the invention described in claim 2, if the outer diameters of the double row balls are the same and the number of balls on the outer side is set larger than the number of balls on the inner side, Bearing life can be ensured while achieving high rigidity.

  Further, as in the invention according to claim 3, if the corners of the groove shoulders of the respective rolling surfaces are flattened to form a smooth arc shape, the contact between each rolling surface and the ball Even if the contact ellipse is applied to the shoulder portion of the groove, the edge load can be prevented from occurring, and the life of the bearing can be extended.

  Moreover, if the corner | angular part of each said rolling surface is formed by simultaneous grinding with the said rolling surface with the total type grindstone after heat processing like invention of Claim 4, a joining part will be formed more smoothly. can do.

  Further, in the invention according to claim 5, the inner member integrally has a wheel mounting flange at one end, and one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, A hub wheel formed with a small-diameter step portion extending in the axial direction from the inner rolling surface, and the other inner rolling member that is press-fitted into the small-diameter step portion of the hub wheel and faces the outer surface of the double row on the outer periphery. A mortar-shaped recess is formed at the outer end of the hub wheel, and the depth of the recess is at least near the groove bottom of the inner raceway surface of the hub wheel. Since the outer shape of the hub wheel is formed so as to have a substantially uniform thickness corresponding to the recess, it is possible to simultaneously solve the conflicting problems of lightening, compactness and high rigidity of the device. Can do.

  The wheel bearing device according to the present invention includes an outer member having a double row outer raceway formed on the inner periphery, and a double row inner raceway facing the outer row raceway on the outer periphery. A wheel bearing device comprising: a formed inner member; and a double-row ball rotatably accommodated between both rolling surfaces of the inner member and the outer member. The pitch circle diameter of the outer side ball is set to be larger than the pitch circle diameter of the inner side ball, and the corners of the counter part of each rolling surface are flattened into a smooth arc shape. Since it is formed, it is possible to suppress ball contact flaws during assembly, hitting due to ball vibration, and the like, improving the acoustic characteristics of the bearing and improving the reliability of product quality. Therefore, it is possible to provide a wheel bearing device in which the rigidity of the device is increased and the life of the bearing is extended.

  A body mounting flange for mounting to the knuckle on the outer periphery is integrated, an outer member with a double row outer raceway formed on the inner periphery, and a wheel mounting flange for mounting the wheel on one end is integrated. A hub wheel having one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, a small diameter step portion extending in the axial direction from the inner rolling surface, and a small diameter of the hub wheel An inner member consisting of an inner ring that is press-fitted into a stepped portion and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and both rolling of the inner member and the outer member A plurality of balls that are rotatably accommodated between the surfaces, and the inner ring is pivoted with respect to the hub ring by a caulking portion formed by plastically deforming an end of the small diameter step portion radially outward. In the wheel bearing device fixed in the direction, the outer side of the double row balls The pitch circle diameter of the inner side balls is set to be larger than the pitch circle diameter of the inner side balls, the outer diameters of the double row balls are the same, and the number of the outer side balls is larger than the number of the inner side balls. In addition, the counter part of each rolling surface is formed into a smooth arc shape by crushing the corners by simultaneous grinding with the rolling surface by a general-purpose grindstone after heat treatment.

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 bearing row on the outer side of FIG. 1, and FIG. FIG. 4 is an explanatory view showing grinding of the outer member after heat treatment, FIG. 5 (a) is an explanatory view showing grinding of the hub wheel after heat treatment, (B) is explanatory drawing which shows the grinding process of the inner ring | wheel after heat processing. In the following description, the side closer to the outer side of the vehicle in a state assembled to the vehicle is referred to as the outer side (left side in the drawing), and the side closer to the center is referred to as the inner side (right side in the drawing).

  This wheel bearing device is for a driven wheel called a third generation, and includes an inner member 1, an outer member 2, and a double row of balls 3 accommodated between the members 1 and 2 so as to roll freely. 3 are provided. The inner member 1 includes a hub ring 4 and an inner ring 5 that is press-fitted into the hub ring 4 through a predetermined scissors. The hub wheel 4 integrally has a wheel mounting flange 6 for mounting a wheel (not shown) at one end, and has one (outer side) inner rolling surface 4a on the outer periphery and the inner rolling surface 4a. A small-diameter step 4b is formed through an axial portion 7 extending in the axial direction. Hub bolts 6a are implanted in the wheel mounting flange 6 at equal intervals in the circumferential direction, and circular holes 6b are formed between the hub bolts 6a. The circular hole 6b can not only contribute to weight reduction, but also a fastening jig such as a wrench can be inserted from the circular hole 6b in the assembly / disassembly process of the apparatus, and the work can be simplified.

  The inner ring 5 is formed by forming the other (inner side) inner rolling surface 5a on the outer periphery and press-fitting into the small-diameter step portion 4b of the hub wheel 4 and plastically deforming the end portion of the small-diameter step portion 4b. It is fixed in the axial direction by the caulking portion 4c. The inner ring 5 is made of high carbon chrome steel such as SUJ2, and is hardened in the range of 58 to 64 HRC up to the core part by quenching.

  The hub wheel 4 is formed of medium carbon steel containing carbon 0.40 to 0.80 wt% such as S53C, and the inner raceway surface 4a and the inner side base portion 6c of the wheel mounting flange 6 to the small diameter step portion 4b. Thus, the surface hardness is set to a range of 58 to 64 HRC by induction hardening. The caulking portion 4c is kept in the surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 6, the fretting resistance of the small-diameter step portion 4b serving as the fitting portion of the inner ring 5 is improved, and the minute There is no occurrence of cracks and the like, and the plastic working of the caulking portion 4c can be performed smoothly.

  The outer member 2 integrally has a vehicle body mounting flange 2c to be attached to a knuckle (not shown) on the outer periphery, and the outer side outer rolling facing the inner rolling surface 4a of the hub wheel 4 on the inner periphery. The surface 2a and the inner side outer rolling surface 2b facing the inner rolling surface 5a of the inner ring 5 are integrally formed. Double-row balls 3 and 3 are accommodated between these rolling surfaces, and are held by the cages 9 and 10 so as to roll freely. This outer member 2 is formed of medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 2a and 2b have a surface hardness in the range of 58 to 64HRC by induction hardening. Has been cured. And the seal | sticker 11 is mounted | worn with the outer side edge part of the annular space formed between the outer member 2 and the inner member 1, and the rotational speed of a wheel is detected in an inner side edge part (inner ring 5). The magnetic encoder 12 is fixed, and a cap (not shown) that covers the open end of the outer member 2 is mounted. The seal 11 and the cap prevent leakage of grease sealed inside the bearing and intrusion of rainwater, dust, and the like from the outside into the bearing. In addition, although the 3rd generation structure by the side of a driven wheel was illustrated here, the wheel bearing apparatus which concerns on this invention is not restricted to this, A 1st and 2nd generation, or a 4th generation structure may be sufficient.

  Here, in the present embodiment, the pitch circle diameter PCDo of the outer side ball 3 is set larger than the pitch circle diameter PCDi of the inner side ball 3. The outer diameter d of the double-row balls 3 and 3 is the same, but due to the difference in the pitch circle diameters PCDo and PCDi, the number of the outer side balls 3 is set larger than the number of the inner side balls 3. ing.

  The outer shape of the hub wheel 4 is such that the counter part A from the groove bottom part of the inner rolling surface 4a, the shaft-like part 7 extending in the axial direction from the counter part A, the tapered step part 7a, and the inner ring 5 are abutted. It continues to the small-diameter step 4b through the shoulder 8. A mortar-shaped recess 13 is formed at the outer end of the hub wheel 4. The depth of the recess 13 is a depth that extends beyond the groove bottom of the inner rolling surface 4a to the vicinity of the stepped portion 7a of the shaft-like portion 7. Since the recess 13 is formed along the outer shape of the hub wheel 21, the outer side of the hub wheel 4 has a substantially uniform thickness. Further, along with the difference between the pitch circle diameters PCDo and PCDi, the inner raceway surface 4a of the hub wheel 4 is formed to have a larger diameter than the inner raceway surface 5a of the inner race 5, and the outer diameter of the shaft portion 7 is inwardly rolled. The diameter is set larger than the groove bottom diameter of the running surface 5a.

  On the other hand, in the outer member 2, the outer side outer rolling surface 2a is formed with a larger diameter than the inner side outer rolling surface 2b due to the difference in pitch circle diameters PCDo and PCDi, and the outer side outer rolling surface 2b is formed. The running surface 2a continues to the small-diameter side shoulder 16 via the cylindrical shoulder portion 14 and the stepped portion 15, and then continues to the inner side outer rolling surface 2b. The groove bottom diameter of the outer rolling surface 2b and the inner diameter of the shoulder 14 on the large diameter side are set to be approximately the same size.

  In the wheel bearing device having such a configuration, the pitch circle diameter PCDo of the outer side ball 3 is set to be larger than the pitch circle diameter PCDi of the inner side ball 3, and the number of balls 3 is set to be larger on the outer side. Therefore, the bearing rigidity of the outer side portion is increased compared to the inner side, and the life of the bearing can be extended. Furthermore, since the recess 13 is formed along the outer shape at the outer end of the hub wheel 4 and the outer side of the hub wheel 4 is set to a uniform thickness, the device is lighter, more compact and more rigid. It is possible to solve the conflicting problem.

  Further, in this embodiment, after improving the bearing rigidity of the outer side portion, the ratio d / PCDi of the outer diameter d of the ball 3 to the pitch circle diameter PCDi of the inner side ball 3 is set within a predetermined range, here 0.14 ≦ (d / PCDi) ≦ 0.25. That is, even if the pitch circle diameter PCDi is the same, the bearing rigidity is increased by reducing the outer diameter d of the balls 3 and increasing the number thereof, so that the smaller the outer diameter d of the balls 3 is from the viewpoint of rigidity. It is preferred. However, since the rolling fatigue life decreases as the outer diameter d of the ball 3 decreases, it is preferable that the outer diameter d of the ball 3 is larger from the viewpoint of life. Here, when the relationship between the pitch circle diameter PCDi and the outer diameter d of the ball 3 is obtained by FEM analysis (analysis by the finite element method), when d / PCDi exceeds 0.25, the wheel bearing device is rigid. On the other hand, it was found that when d / PCDi is less than 0.14, the rolling fatigue life is insufficient as a wheel bearing device. Therefore, the pitch circle diameter PCDo of the outer side ball 3 is increased to improve the bearing rigidity of the outer side portion, and the relationship between the pitch circle diameter PCDi of the inner side ball 3 and the outer diameter d of the ball 3 is increased. Is defined in the range of 0.14 ≦ (d / PCDi) ≦ 0.25, the bearing life can be ensured while achieving high rigidity.

  Furthermore, in this embodiment, the corners of the groove shoulders 17, 18, 19, and 20 of each rolling surface are flattened to form a smooth arc shape, and the corners of the counter parts A, B, C, and D are formed. The part is also flattened to form a smooth arc. Specifically, as shown in an enlarged view in FIGS. 2 and 3, the chamfered axial dimension La is 0.15 to 0.8 mm, preferably 0.15 to 0.3 mm, and the radial dimension Lr is 0. .15 to 0.8 mm, preferably 0.15 to 0.3 mm, and the corner radius R is 0.15 to 2.0 R, preferably 0.45 to 0.7 R. It is set and each connecting part is formed smoothly. If the corner radius R is less than 0.15R, the ball 3 is easily scratched. On the other hand, if the corner radius R exceeds 2.0R, the contact ellipse of the ball 3 is formed in the groove shoulder portions 17 to 20. Is undesirably easy to get on and disengage from the inner rolling surface 4a.

  As shown in FIGS. 4 and 5, the groove shoulder portions 17 to 20 and the counter portions A to D of each rolling surface are ground simultaneously with the rolling surface by a general-purpose grindstone after heat treatment. That is, as shown in FIG. 4, the double row outer rolling surfaces 2 a and 2 b of the outer member 2 are formed by being integrally ground by the overall grindstone 21, but at this time, the groove shoulder portions 18 and 20 are formed. And the counter parts B and D are also ground simultaneously by this general-purpose grindstone 21. Further, as shown in FIG. 5A, the base portion 6c and the inner rolling surface 4a of the wheel mounting flange 6 serving as a seal land portion are formed by being integrally grinded by a general-purpose grindstone 22, The groove shoulder portion 17 and the counter portion A are also simultaneously ground by the total-type grindstone 22. Also in the inner ring 5, as shown in FIG. 5 (b), the inner raceway surface 5a, the outer diameter surface 5b on the large diameter side into which the magnetic encoder 12 is press-fitted, and the end surface 5c on the small diameter (front) side are total. The grindstone 23 is integrally ground and formed. At this time, the groove shoulder portion 19 and the counter portion C are simultaneously ground by the total grindstone 23.

  Thus, in this embodiment, the groove shoulders 17 to 20 and the counter parts A to D of each rolling surface are simultaneously ground by the total type grindstones 21, 22, and 23 together with the rolling surfaces 2a, 2b, 4a, and 5a. Since the corners are flattened and formed into a smooth arc shape, even if the contact ellipse due to the contact between each rolling surface 2a, 2b, 4a, 5a and the ball 3 is applied to the corners, the edge load is generated. In addition to improving the acoustic characteristics of the bearing, it is possible not only to prevent the occurrence of the bearing and extend the life of the bearing, but also to prevent ball contact damage during assembly and damage caused by ball vibration. , Can improve the reliability of product quality. Therefore, it is possible to provide a wheel bearing device in which the rigidity of the device is increased and the life of the bearing is extended.

  FIG. 6 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention. In addition, the same code | symbol is attached | subjected to the site | part same as the embodiment mentioned above, the same component, or the site | part which has the same function, and the detailed description is abbreviate | omitted.

  This wheel bearing device is an outer ring rotating type called a second generation for a driven wheel, and is composed of an inner member 24, an outer member 25, and a plurality of rolls accommodated between the members 24, 25. A row of balls 3 and 3 is provided. The inner member 24 includes a pair of inner rings 26 and 5 having inner rolling surfaces 26a and 5a formed on the outer periphery.

  The outer member 25 is made of medium carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and integrally has a wheel mounting flange 6 for mounting a wheel (not shown) on the outer periphery, and on the inner periphery. Double row outer rolling surfaces 2a, 2b are formed. Between the rolling surfaces, double-row balls 3 and 3 are accommodated so as to roll freely via cages 9 and 10 to form a back-to-back type double-row angular ball bearing. A seal 27 is attached to the inner side end of the outer member 25, and a labyrinth seal 28 is formed between the outer side end and the inner ring 26, and is attached to the opening end of the outer member 25. A cap (not shown) prevents leakage of grease sealed inside the bearing and intrusion of rainwater and dust from the outside into the bearing.

  Here, in the present embodiment, the pitch circle diameter PCDo of the outer side ball 3 is set larger than the pitch circle diameter PCDi of the inner side ball 3. The outer diameter d of the double-row balls 3 and 3 is the same, but due to the difference in the pitch circle diameters PCDo and PCDi, the number of the outer side balls 3 is set larger than the number of the inner side balls 3. ing. Further, along with the difference in pitch circle diameters PCDo and PCDi, the inner rolling surface 26a of the inner ring 26 on the outer side is formed to have a larger diameter than the inner rolling surface 5a of the inner ring 5 on the inner side.

  Also in the present embodiment, as in the above-described embodiment, the bearing rigidity of the outer side portion is increased compared to the inner side, the bearing life can be extended, and the groove shoulder portions 17 to 20 of each rolling surface can be achieved. Since the corners of the counter parts A to D are flattened and formed into a smooth arc shape, it is possible to suppress contact damage of the ball 3 at the time of assembly, damage due to vibration, and the like. In this type of wheel bearing device, it is possible to suppress the ball 3 from being damaged by vibration or impact load during transportation or in an assembly process by an automobile manufacturer.

  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 device 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.

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 outer side bearing row | line | column of FIG. It is a principal part enlarged view which shows the bearing row | line | column of the inner side of FIG. It is explanatory drawing which shows the grinding process of the outer member after heat processing. (A) is explanatory drawing which shows the grinding process of the hub wheel after heat processing. (B) is explanatory drawing which shows the grinding process of the inner ring | wheel after heat processing. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

Explanation of symbols

1, 24 ... Inner member 2, 25 ... Outer member 3 ...・ ・ ・ ・ ・ Ball 4 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Hub wheel 4a, 5a, 26a ・ ・ ・ ・ ・ ・ ・ ・ Inner rolling surface 4b ・ ・ ・ ・ ・ ・ ・.... Small diameter step 4c ... Caulking part 5, 26 ... Inner ring 5b ... · · · · · · · · · · · · · · · · · · · · · ··・ ・ ・ ・ ・ ・ Wheel mounting flange 6a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Hub bolt 6b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Circular hole 6c ・ ・ ・························································· 8, 14, 16 ... shoulder 9, 10, ... retainer 11, 27 ... Seal 12 ... Magnetic encoder 13 ... Recess 15 ... ... Stepped parts 17, 18, 19, 20, ... Groove shoulder parts 21, 22, 23 ...・ ・ ・ ・ Labyrinth seal 50 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Bearing bearing device 51 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer member 51a・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer rolling surface 51b on the outer side ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer rolling surface 51c on the inner side ... .... Body mounting flange 52 ... Hub 52a, 54a ... Inner rolling surface 52b ... Small diameter step 52c ... Caulking part 53 ............ Wheel mounting flange 54 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner ring 55 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... Inner members 56, 57 ... Balls 58, 59 ... Cage 60, 61 ... ··· Seal 62 ······································································ ···················· Counter D1 ··········· Pitch circle diameter D2 of the ball on the outer side・ Pitch circle diameter d of inner side ball ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ Ball outer diameter La ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Chamfer axial dimension Lr ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Chamfer radial dimension PCDo ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter of the outer side ball PCDi ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter R of the inner side ball ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ Round corner

In order to achieve the object, the invention according to claim 1 of the present invention is such that an outer member having a double row outer rolling surface formed on the inner periphery and an outer member facing the double row outer rolling surface on the outer periphery. An inner member in which a double row inner rolling surface is formed, and a double row ball accommodated in a freely rollable manner between the inner member and the outer member. In the bearing device, the pitch circle diameter of the outer side ball of the double row balls is set to be larger than the pitch circle diameter of the inner side ball, and a corner portion of the counter portion of each rolling surface is The configuration formed in a smooth arc shape was adopted.

As described above, in the wheel bearing device constituted by the double row angular ball bearing, the pitch circle diameter of the outer side ball among the double row balls is set larger than the pitch circle diameter of the inner side ball. together, the corners of the counter section of each rolling surface is formed into a smooth arcuate shape, it is possible to suppress the bruises and the like due to the impact load at ball contact scratches and automobile manufacturers assembling process of the assembly, The acoustic characteristics of the bearing can be improved, and the reliability of product quality can be improved. Therefore, it is possible to provide a wheel bearing device in which the rigidity of the device is increased and the life of the bearing is extended.

It is preferable as defined in claim 3, wherein if it is formed in the groove shoulder portion of the corner a smooth arcuate respective rolling surfaces, the contact ellipse due to the contact between each rolling surface and the ball Even if it hits the groove shoulder, it is possible to suppress the occurrence of edge load, and to extend the life of the bearing.

The wheel bearing device according to the present invention includes an outer member having a double row outer raceway formed on the inner periphery, and a double row inner raceway facing the outer row raceway on the outer periphery. A wheel bearing device comprising: a formed inner member; and a double-row ball rotatably accommodated between both rolling surfaces of the inner member and the outer member. pitch diameter of the outer side of the ball while being set greater than the pitch circle diameter of the inner side of the ball, the corners of the counter section of each rolling surface is formed into a smooth arcuate shape of the Therefore, it is possible to suppress ball contact scratches and ball scratches caused by ball vibration at the time of assembly, thereby improving the acoustic characteristics of the bearing and improving the reliability of product quality. Therefore, it is possible to provide a wheel bearing device in which the rigidity of the device is increased and the life of the bearing is extended.

A body mounting flange for mounting to the knuckle on the outer periphery is integrated, an outer member with a double row outer raceway formed on the inner periphery, and a wheel mounting flange for mounting the wheel on one end is integrated. A hub wheel having one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, a small diameter step portion extending in the axial direction from the inner rolling surface, and a small diameter of the hub wheel An inner member consisting of an inner ring that is press-fitted into a stepped portion and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and both rolling of the inner member and the outer member A plurality of balls that are rotatably accommodated between the surfaces, and the inner ring is pivoted with respect to the hub ring by a caulking portion formed by plastically deforming an end of the small diameter step portion radially outward. In the wheel bearing device fixed in the direction, the outer side of the double row balls The pitch circle diameter of the inner side balls is set to be larger than the pitch circle diameter of the inner side balls, the outer diameters of the double row balls are the same, and the number of the outer side balls is larger than the number of the inner side balls. with many being set, the counter portion of the rolling surface, corner by the rolling surface and the co-ground by grindstone after the heat treatment is formed into a smooth arcuate shape.

Furthermore, in this embodiment, the corners of the groove shoulders 17, 18, 19, and 20 of each rolling surface are flattened (rounded) to form a smooth arc shape, and the counter parts A, B, The corners of C and D are also flattened to form a smooth arc. Specifically, as shown in an enlarged view in FIGS. 2 and 3, the chamfered axial dimension La is 0.15 to 0.8 mm, preferably 0.15 to 0.3 mm, and the radial dimension Lr is 0. .15 to 0.8 mm, preferably 0.15 to 0.3 mm, and the corner radius R is 0.15 to 2.0 R, preferably 0.45 to 0.7 R. It is set and each connecting part is formed smoothly. If the corner radius R is less than 0.15R, the ball 3 is easily scratched. On the other hand, if the corner radius R exceeds 2.0R, the contact ellipse of the ball 3 is formed in the groove shoulder portions 17 to 20. Is undesirably easy to get on and disengage from the inner rolling surface 4a.

In order to achieve the object, the invention according to claim 1 of the present invention is such that an outer member having a double row outer rolling surface formed on the inner periphery and an outer member facing the double row outer rolling surface on the outer periphery. An inner member in which a double row inner rolling surface is formed, and a double row ball accommodated in a freely rollable manner between the inner member and the outer member. In the bearing device, the pitch circle diameter of the outer side ball of the double row balls is set to be larger than the pitch circle diameter of the inner side ball, and a corner portion of the counter portion of each rolling surface is It was formed in a smooth circular arc shape, and a configuration was adopted in which each rolling surface, a groove shoulder portion of each rolling surface, and the counter portion were simultaneously ground by a general grinding wheel .

As described above, in the wheel bearing device constituted by the double row angular ball bearing, the pitch circle diameter of the outer side ball among the double row balls is set larger than the pitch circle diameter of the inner side ball. In addition, the corners of the counter portion of each rolling surface are formed in a smooth arc shape, and each rolling surface, the groove shoulder portion of each rolling surface, and the counter portion are simultaneously ground by a general grindstone. As a result, it is possible to suppress ball contact scratches during assembly and impact damage due to impact loads in the assembly process of automobile manufacturers, improving the acoustic characteristics of the bearings and improving the reliability of product quality. it can. Therefore, it is possible to provide a wheel bearing device in which the rigidity of the device is increased and the life of the bearing is extended.

The wheel bearing device according to the present invention includes an outer member having a double row outer raceway formed on the inner periphery, and a double row inner raceway facing the outer row raceway on the outer periphery. A wheel bearing device comprising: a formed inner member; and a double-row ball rotatably accommodated between both rolling surfaces of the inner member and the outer member. with a pitch circle diameter of the outer side of the ball of the is set greater than the pitch circle diameter of the inner side of the ball, the corners of the counter section of each rolling surface is formed into a smooth arcuate shape Since each rolling surface, the groove shoulder portion of each rolling surface, and the counter portion are simultaneously ground by a grindstone, it is possible to suppress ball contact scratches during assembly and scratches caused by ball vibration. Can improve the acoustic characteristics of the bearing and improve the reliability of product quality. It is possible. Therefore, it is possible to provide a wheel bearing device in which the rigidity of the device is increased and the life of the bearing is extended.

Claims (5)

An outer member having a double row outer rolling surface formed on the inner periphery, an inner member having a double row inner rolling surface opposed to the outer surface of the double row formed on the outer periphery, In a wheel bearing device comprising a lateral member and a double row of balls accommodated so as to roll between both rolling surfaces of the outer member,
The pitch circle diameter of the outer side balls of the double row balls is set larger than the pitch circle diameter of the inner side balls, and the corners of the counter part of each rolling surface are crushed. A wheel bearing device characterized by being formed in a smooth arc shape.   The wheel bearing device according to claim 1, wherein the outer diameters of the double row balls are the same, and the number of the outer side balls is set to be larger than the number of the inner side balls.   The wheel bearing device according to claim 1 or 2, wherein a corner portion of a groove shoulder portion of each rolling surface is flattened to form a smooth arc shape.   The wheel bearing device according to any one of claims 1 to 3, wherein a corner portion of each rolling surface is formed by simultaneous grinding with the rolling surface by a general-purpose grindstone after heat treatment.   The inner member integrally has a wheel mounting flange at one end, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small diameter extending in the axial direction from the inner rolling surface. A hub ring formed with a stepped portion, and an inner ring press-fitted into a small-diameter stepped portion of the hub wheel and formed with the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, A mortar-shaped recess is formed at the outer end of the hub wheel, and the depth of the recess is at least near the groove bottom of the inner raceway surface of the hub wheel, and the outer shape of the hub wheel is the recess. The wheel bearing device according to any one of claims 1 to 4, wherein the wheel bearing device is formed so as to have a substantially uniform thickness corresponding to the location.

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