JP5024850B2 - Wheel bearing device - Google Patents

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 light weight as well as 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 A large 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. Therefore, a wheel bearing device shown in FIG. 5 is known as a wheel bearing device that has improved rigidity during turning without increasing the size of the device.

  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 having 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 surfaces 51a and 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 a 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 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

  In such a conventional wheel bearing device 50, the pitch circle diameter D1 of the outer ball 56 is set to be larger than the pitch circle diameter D2 of the inner ball 57, and accordingly, the inner rolling of the hub wheel 52 is performed. The surface 52a is larger in diameter than the inner rolling surface 54a of the inner ring 54. As a result, the rigidity of the outer bearing row is improved, and the life of the wheel bearing device 50 can be extended. However, since the outer side of the hub wheel 52 is formed to have an enlarged diameter, an increase in the weight of at least the enlarged diameter cannot be avoided, and there is a limit to reducing the weight of the device.

  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 simultaneously solves the conflicting problems of light weight, compactness, and high rigidity of the device.

In order to achieve the object, the invention according to claim 1 of the present invention includes an outer member having a double row outer rolling surface formed on the inner periphery, and a wheel mounting flange for mounting the wheel at one end. A hub wheel integrally formed and having one inner rolling surface opposed to the double-row outer rolling surface on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface, and the hub wheel An inner member formed of an inner ring that is press-fitted into a small-diameter step portion and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and both the inner member and the outer member. In a wheel bearing device including a double row ball accommodated so as to be able to roll between rolling surfaces, a pitch circle diameter of an outer side ball of the double row balls is a pitch circle diameter of an inner side ball. Is set to a larger diameter than the mortar shape at the outer end of the hub wheel A recess is formed, and the bottom position of the recess is on the inner side with respect to the center position between the balls in the double row, and on the outer side with respect to the shoulder portion with which the inner ring is abutted. The hub wheel is formed so that the position of the recess in the contact angle direction of the ball on the outer side protrudes toward the inner diameter side so that the shape of the place has a uniform thickness along the outer shape of the hub ring. The thickness of the ball on the inner rolling surface in the contact angle direction is in the range of 0.2 to 0.3 of the diameter of the contact point position of the ball on the inner rolling base and the inner rolling surface of the inner rolling surface. Is set to

In this way, in the wheel bearing device constituted by the double row angular ball bearing having the wheel mounting flange at one end, the pitch circle diameter of the outer side ball of the double row balls is the pitch circle of the inner side ball. It is set to a diameter larger than the diameter, and a mortar-shaped recess is formed at the outer end of the hub wheel, and the bottom position of this recess is on the inner side than the center position between the double row balls. The outer ring is positioned to the outer side of the shoulder where the inner ring is abutted, and the concave shape is uniform along the outer shape of the hub ring in the contact angle direction of the outer side ball. It is formed so that the position of the recess protrudes toward the inner diameter side, and the wall thickness in the contact angle direction of the ball on the inner raceway surface of the hub wheel is such that the base portion on the inner side of the wheel mounting flange and the ball on the inner raceway surface Directly at the contact point position Because of being set in a range of 0.2 to 0.3, it is possible to provide a wheel bearing apparatus which solves simultaneously contradictory problem that weight and size and a high rigidity of the apparatus.

  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, A desired bearing life can be ensured while achieving high rigidity.

According to a third aspect of the present invention, there is provided an axial portion extending in the axial direction from the groove bottom portion of the inner raceway surface of the hub wheel to the small diameter step portion, and the shaft portion and the inner ring A taper-shaped step is formed between the shoulder to be abutted, and the depth of the recess exceeds the groove bottom of the inner rolling surface and reaches a range of the taper-step. If the thickness of the ball on the inner rolling surface in the contact angle direction is set to be thicker than the thickness of the groove bottom of the inner rolling surface, the rigidity of the hub wheel is ensured and the weight is further reduced. Can be achieved.

Further, as in the invention described in claim 4 , the ratio d / PCDi of the outer diameter d of the ball to the pitch circle diameter PCDi of the inner side ball is 0.14 ≦ (d / PCDi) ≦ 0.25. If it is prescribed | regulated in the range of this, bearing life can be ensured, achieving high rigidity.

The wheel bearing device according to the present invention integrally has an outer member having a double row outer raceway formed on the inner periphery, and a wheel mounting flange for mounting a wheel on one end, and the outer periphery includes One inner rolling surface facing the outer rolling surface of the row, a hub wheel formed with a small-diameter step portion extending in the axial direction from the inner rolling surface, and a small-diameter step portion of the hub wheel are press-fitted into the outer periphery. An inner member formed of an inner ring formed with the other inner rolling surface facing the double row outer rolling surface, and freely rollable between both rolling surfaces of the inner member and the outer member. In the wheel bearing device including the double row balls accommodated therein, the pitch circle diameter of the outer side balls among the double row balls is set larger than the pitch circle diameter of the inner side balls. A mortar-shaped recess is formed at the outer end of the hub wheel. The bottom position is on the inner side with respect to the center position between the balls in the double row, and on the outer side with respect to the shoulder to which the inner ring is abutted, and the shape of the recess is the outer shape of the hub ring. The contact angle of the ball on the inner raceway surface of the hub wheel is formed such that the position of the recess in the contact angle direction of the outer side ball protrudes toward the inner diameter side so as to have a uniform thickness along Since the thickness in the direction is set in the range of 0.2 to 0.3 of the diameter of the contact point position of the ball on the inner base of the wheel mounting flange and the inner rolling surface , the weight of the device is reduced. It is possible to provide a wheel bearing device that can simultaneously solve the conflicting problems of compactness and high rigidity.

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. A mortar-shaped recess is formed at the outer end of the hub ring, and the bottom position of the recess is on the inner side of the center position between the balls in the double row, and the inner ring is The contact angle direction of the ball on the outer side is such that the concave portion has a uniform thickness along the outer shape of the hub wheel. position of the recesses is formed so as to protrude radially inward, the thickness of the contact angle direction of the ball in the inner raceway surface of the hub wheel, the base of the inner side of the wheel mounting flange and the inner raceway surface Contact of the ball It is set in a range of 0.2 to 0.3 of the diameter of the position.

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 the hub wheel of FIG. 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 press-fitted into the hub ring 4 through a predetermined shimiro.

  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 in a circumferentially equal distribution, 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 8.

  The hub wheel 4 is made of medium carbon steel containing 0.40 to 0.80 wt% of carbon 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 8 is kept in the surface hardness after forging. This has sufficient mechanical strength against the rotational bending load applied to the wheel mounting flange 6, improves the fretting resistance of the small-diameter stepped portion 4b serving as the fitting portion of the inner ring 5, and performs caulking. There is no occurrence of minute cracks or the like during processing, and the plastic processing of the crimped portion 8 can be performed smoothly. 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 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 9 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 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. On the outer periphery of the hub wheel 4, the shaft-like portion 7 formed with a small diameter through the step portion 7 a from the counter portion 14 that gradually decreases in diameter from the inner rolling surface 4 a toward the inner side, and the inner ring 5 are abutted. A small-diameter step 4b is formed through the shoulder 7b. Further, with the difference in pitch circle diameters PCDo and PCDi, the inner raceway surface 4a of the hub wheel 4 is enlarged in diameter than the inner raceway surface 5a of the inner race 5, and the groove bottom diameter of this inner raceway surface 5a and the axial shape The outer diameter of the part 7 is set to substantially the same dimension.

  On the other hand, in the outer member 2, with the difference in pitch circle diameters PCDo and PCDi, the outer-side outer rolling surface 2a has a diameter larger than the inner-side outer rolling surface 2b, and the outer-side outer rolling surface 2a. The outer side rolling surface 2b on the inner side is formed following the shoulder portion 16 on the small diameter side through the cylindrical shoulder portion 15 and the step portion 15a. The groove bottom diameter of the outer rolling surface 2b and the inner diameter of the shoulder 15 on the large diameter side are set to be substantially the same size.

  In the present embodiment, the ratio d / PCDi of the outer diameter d of the ball 3 to the pitch circle diameter PCDi of the inner ball 3 is improved within a predetermined range after improving the bearing rigidity of the outer side portion. It is specified in the range of 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. Although the rolling fatigue life is reduced as the outer diameter d of the ball 3 becomes smaller, the outer diameter d of the ball 3 is preferably 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. Does not improve. 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.

  Here, a mortar-shaped recess 13 is formed at the outer side end of the hub wheel 4. The recess 13 is formed by forging, and its depth is set to the vicinity of the groove bottom of the inner side rolling surface 4a on the outer side, and the thickness of the outer side of the hub wheel 4 corresponding to the recess 13 is increased. It is formed so as to be substantially uniform. When a moment load is applied to the wheel mounting flange 6, it is considered that the hub wheel 4 is deformed starting from the contact angle α of the outer-side ball 3. Focused on thickness. As shown in an enlarged view in FIG. 2, the base portion 6c of the wheel mounting flange 6 serving as a seal land portion is formed in an arc surface having a predetermined radius of curvature. The minimum thickness t1 of the base portion 6c and its portion As a result of obtaining the rigidity of the hub wheel 4 by the FEM analysis from the relationship with the diameter d1 of the hub, by setting the minimum wall thickness t1 in the range of 0.2 ≦ t1 / d1 ≦ 0.3, the hub corresponding to the use condition Weight reduction can be achieved while ensuring the strength and rigidity of the wheel 4. That is, when the minimum thickness t1 of the base portion 6c is less than 20% of the diameter d1 of the portion, the deformation becomes large and desired rigidity cannot be obtained. On the other hand, even if the minimum thickness t1 exceeds 30% of the diameter d1, the rigidity is not increased so much, which is not preferable because it causes a weight increase. Similarly to the base portion 6c of the wheel mounting flange 6, the relationship between the wall thickness t2 of the ball 3 on the inner rolling surface 4a in the contact angle α direction and the diameter (ball contact diameter) t2 of the portion is 0.2 ≦ It is set in the range of t2 / d2 ≦ 0.3.

  In the wheel bearing device having such a configuration, 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, 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. Further, a recess 13 is formed at the outer side end of the hub wheel 4, and the thicknesses t1 and t2 are set within a predetermined range corresponding to the recess 13, and the outer side of the hub wheel 4 has a substantially uniform thickness. Since the outer shell is set to have a predetermined shape and size so that the following can be obtained, it is possible to provide a wheel bearing device that simultaneously solves the conflicting problems of lightweight, compact and high rigidity of the device.

  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 the hub wheel of FIG. Note that this embodiment basically differs from the above-described embodiment (FIG. 1) only in the configuration of the hub wheel, and the same reference numerals are given to other identical parts, identical parts, or parts having the same function. In addition, the detailed description is omitted.

  This wheel bearing device is for a driven wheel called a third generation, and is an inner member 17, an outer member 2, and a double row of balls 3 accommodated in a freely rolling manner between both members 17, 2. 3 are provided. The inner member 17 includes a hub ring 21 and an inner ring 5 that is press-fitted into the hub ring 18 through a predetermined shimiro.

  The hub ring 18 is made of medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and is deeper than the mortar-shaped recess 13 (shown by a two-dot chain line) at the end on the outer side. A place 19 is formed. On the outer periphery of the hub wheel 18, a small diameter step portion 4 b is provided via a shaft portion 20 extending in the axial direction from the groove bottom portion of the inner rolling surface 4 a, a tapered step portion 21, and a shoulder portion 7 b with which the inner ring 5 is abutted. Is formed. And with the difference in pitch circle diameters PCDo and PCDi, the inner raceway surface 4a of the hub wheel 18 is expanded in diameter than the inner raceway surface 5a of the inner race 5, and the outer diameter of the shaft-like portion 20 is the inner raceway surface. The diameter is set larger than the groove bottom diameter of 5a.

  The depth of the recess 19 is a depth that extends beyond the groove bottom portion of the inner rolling surface 4 a to the vicinity of the stepped portion 21. The outer shape of the hub wheel 18 is formed so as to have a uniform thickness corresponding to the recess 19. That is, as shown in an enlarged view in FIG. 4, in the present embodiment, the inner rolling surface 4a is set to be larger than the minimum thickness (thickness at the groove bottom diameter d0 position) t0, and the seal land portion The minimum thickness t1 of the base portion 6c of the wheel mounting flange 6 and the thickness t2 in the direction of the contact angle α are set to be in the range of 0.2 to 0.3 of the diameters d1 and d2 of the portions. As a result, the rigidity of the hub wheel 18 can be ensured and further weight reduction can be achieved.

  In the above-described embodiment, the double row balls 3 and 3 have the same outer diameter d, but the outer diameters d of the balls 3 and 3 may be different. For example, the ball 3 arranged on the outer side may be made smaller in outer diameter d than the ball 3 arranged on the inner side, and the number of balls may be set larger.

  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 on the driven wheel side of the third generation structure.

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 hub wheel of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view which shows the hub wheel of FIG. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

Explanation of symbols

1, 17 ... Inner member 2 ... Outer member 3 ... ······ Balls 4, 18 ·······························································・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Small diameter step 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner ring 5b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Large diameter side Outer diameter surface 5c ......... Small diameter side end face 6 ... Wheel mounting flange 6a ... ······················································· 6・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shaft-shaped part 7a, 15a, 21 ・ ・ ・ ・ ・ ・ ・ ・ Stepped part 7b, 15, 16 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shoulder ························································ 9 ... Seal 12 ... Magnetic encoder 13, 19 ... Recess 14 ... ·············· 50・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer rolling surface 51b on the outer side ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer rolling surface 51c on the inner side ・ ・ ・ ・ ・ ・ ・ ・Car body mounting flange 52 ... Hub wheels 52a, 54a ... Inner rolling surface 52b ... .... Small diameter step 52c ... 53 ... Wheel mounting flange 54 ... Inner ring 55 ...・ ・ Inner members 56, 57 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Balls 58, 59 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Retainer 60, 61 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ Seal d ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Ball outer diameter d0 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Groove bottom of outer rolling surface Diameter d1 ············· Diameter d2 of the minimum wall thickness at the base of the wheel mounting flange Ball contact diameter D1 on the running surface ········· Pitch circle diameter D2 of the outer side ball ··············· Inner ball Pitch circle diameter PCDo ...・ ・ ・ ・ ・ ・ Pitch circle diameter PCDi of outer side ball ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter t0 of inner side ball ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・.... Thickness t1 at the bottom of the groove on the inner rolling surface on the outer side ..... Minimum thickness t2 at the base ... ..Thickness α in the contact angle direction on the inner rolling surface

Claims (4)

An outer member having a double row outer raceway formed on the inner periphery;
A wheel mounting flange for mounting a wheel at one end is integrally formed, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small diameter step extending in the axial direction from the inner rolling surface An inner member comprising a hub wheel formed with a portion, and an inner ring press-fitted into a small-diameter step portion of the hub wheel and having the other inner rolling surface opposed to the outer rolling surface of the double row on the outer periphery. ,
In the wheel bearing device comprising this inner 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 ball of the double row balls is set to be larger than the pitch circle diameter of the inner side ball, and a mortar-shaped recess is formed at the outer side end of the hub wheel. The bottom position of the recess is formed on the inner side with respect to the center position between the balls in the double row, and on the outer side with respect to the shoulder portion with which the inner ring is abutted, and further, the shape of the recess Is formed so that the position of the recess in the contact angle direction of the outer side ball protrudes toward the inner diameter side so that the outer wall has a uniform thickness along the outer shape of the hub ring. The thickness in the contact angle direction of the ball on the running surface is set in a range of 0.2 to 0.3 of the diameter of the contact point position of the ball on the inner base of the wheel mounting flange and the inner rolling surface. For wheels characterized by Receiving apparatus.   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. A shaft-like portion extending in the axial direction from the groove bottom portion of the inner raceway surface of the hub wheel to the small-diameter step portion is formed, and a taper shape is formed between the shaft-like portion and a shoulder portion that abuts against the inner ring. And the depth of the recess is set to a depth beyond the groove bottom of the inner rolling surface to the range of the tapered step, and the contact of the ball on the inner rolling surface The wheel bearing device according to claim 1 or 2 , wherein the thickness in the angular direction is set to be thicker than the thickness of the groove bottom portion of the inner rolling surface. The ratio d / PCDi in the outer diameter d of the ball with respect to the pitch circle diameter PCDi of the inner side of the ball, either 0.14 ≦ (d / PCDi) ≦ 0.25 range defined by and claims 1 to 3, A wheel bearing device according to claim 1.

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