JP4998983B2 - 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 increases bearing rigidity and is lightweight and compact.

  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 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).

  In wheel bearing devices composed of such double-row rolling bearings, the left and right rows of bearings have the same specifications, so that they have sufficient rigidity when stationary, but optimal rigidity is always obtained when the vehicle turns. Absent. 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. Therefore, a wheel bearing device shown in FIG. 3 is known as a wheel bearing device that achieves high rigidity 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-side ball 56 is set to be larger than the pitch circle diameter D2 of the inner-side ball 57, and the outer-side ball 56 is Since the ball 57 is accommodated in a larger number than the ball 57, the bearing rigidity can be increased. However, when the rigidity is further increased, it has been a problem how to effectively increase the rigidity while suppressing the weight.

  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 increases bearing rigidity and is light and compact.

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 that is integrally formed with one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface via the shaft- shaped portion. An inner member formed of an inner ring formed by press-fitting into a small-diameter step portion of the wheel and the hub wheel and having the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery; and the inner member A double row rolling element group that is rotatably accommodated between both rolling surfaces of the outer member, and the pitch of the rolling element group on the side close to the wheel mounting flange among the double row rolling element group Wheel shaft whose circular diameter is set larger than the pitch circular diameter of the rolling element group on the side far from the wheel mounting flange. In the apparatus, the with stepped portion between the shoulder portion which is matched to the shaft-like portion of the hub wheel and the inner ring is formed, conical recess is formed at an end portion of the outer side of the hub wheel, The depth of the recess exceeds the groove bottom portion of the inner raceway surface of the hub wheel and is in the vicinity of the step portion, and the rolling element size of the rolling element group on the side close to the wheel mounting flange is It is larger than the rolling element size of the rolling element group on the side far from the flange, and the number of rolling elements is set to be large.

Thus, the pitch circle diameter of the rolling element group closer to the wheel mounting flange in the double row rolling element group is set larger than the pitch circle diameter of the rolling element group far from the wheel mounting flange. In the wheel bearing device, a stepped portion is formed between the shaft-shaped portion of the hub wheel and the shoulder that is abutted against the inner ring, and a mortar-shaped recess is formed at the outer end of the hub wheel, The depth of this recess exceeds the groove bottom of the inner raceway surface of the hub wheel and is near the step, and the rolling element size of the rolling element group near the wheel mounting flange is the side far from the wheel mounting flange. It is larger than the rolling element size of the rolling element group, and the number of the rolling elements is set to be large, so that it is possible to provide a wheel bearing device that increases bearing rigidity and is lightweight and compact. it can.

  Further, as in the invention described in claim 2, the rolling element may be a ball, and as in the invention described in claim 3, the rolling element is formed of a tapered roller, and the wheel mounting The roller diameter of the tapered roller group on the side close to the flange may be larger than the roller diameter of the tapered roller group on the side far from the wheel mounting flange, and the length of the rollers may be set longer.

  Further, as in the invention according to claim 4, a large collar for guiding the tapered roller is not formed on the large diameter side of the inner rolling surface of the hub wheel, and the outer side of the outer member is not formed. If the large ridge is formed on the large diameter side of the rolling surface, not only can the hub ring be forged and cut, but also the stress concentration generated on the hub ring can be reduced, and the strength and durability can be reduced. Can be improved.

It is preferable as defined in claim 5, wherein if the outer shape of the hub wheel is formed to have a substantially uniform thickness in correspondence with the recess, the high and weight and size of the apparatus The conflicting problem of rigidity can be solved.

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 A hub wheel formed with one inner rolling surface facing the outer rolling surface of the row, a small-diameter step portion extending in an axial direction from the inner rolling surface via the shaft- shaped portion , and a small-diameter step of the hub wheel An inner member formed of an inner ring that is press-fitted into the outer periphery and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and both rolling surfaces of the inner member and the outer member A plurality of rolling element groups accommodated in a freely rotatable manner between them, and the pitch circle diameter of the rolling element group on the side close to the wheel mounting flange among the double row rolling element groups is in the wheel mounting flange. in the wheel bearing device, which is set larger than the pitch circle diameter of the rolling element groups on the far side, the hub wheel A step portion is formed between the shaft-shaped portion and a shoulder portion that is abutted against the inner ring, and a mortar-shaped recess is formed at the outer end of the hub wheel, and the depth of the recess is The rolling element size of the rolling element group on the side close to the wheel mounting flange exceeds the groove bottom of the inner rolling surface of the hub wheel, and the rolling element on the side farther from the wheel mounting flange Since the size of the rolling elements is larger than that of the group and the number of rolling elements is set to be large, it is possible to provide a wheel bearing device that increases the bearing rigidity and is light and compact.

  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 double-row ball group accommodated so as to roll freely between the surfaces, and the pitch circle diameter of the ball group close to the wheel mounting flange in the double-row ball group is far from the wheel mounting flange. Wheel bearings set larger than the pitch circle diameter of the ball group The ball group of the ball group near the wheel mounting flange is larger than the ball diameter of the ball group far from the wheel mounting flange, and the number of balls is set larger, and the hub wheel A mortar-shaped recess is formed at the end of the wheel mounting flange side of this, the depth of this recess is at least near the shaft-shaped portion of the hub wheel, and the outer shape of the hub wheel corresponds to the recess Thus, it is formed to have a substantially uniform thickness.

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.

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. 4 groups. The inner member 1 includes a hub ring 5 and an inner ring 6 press-fitted into the hub ring 5 through a predetermined shimiro.

  The hub wheel 5 integrally has a wheel mounting flange 7 for attaching a wheel (not shown) to an end portion on the outer side, one (outer side) inner rolling surface 5a on the outer periphery, and this inner rolling. A small-diameter step portion 5b is formed through an axial portion 8 extending in the axial direction from the surface 5a. Hub bolts 7a are planted on the wheel mounting flange 7 in a circumferentially uniform manner, and circular holes 7b are formed between the hub bolts 7a. The circular hole 7b not only contributes to weight reduction, but also a fastening jig such as a wrench can be inserted from the circular hole 7b in the assembly / disassembly process of the apparatus, and the work can be simplified.

  The inner ring 6 is formed with the other (inner side) inner raceway surface 6a on the outer periphery and is press-fitted into the small-diameter stepped portion 5b of the hub wheel 5 to form a back-to-back type double row angular contact ball bearing. The inner ring 6 is fixed in the axial direction by a caulking portion 5c formed by plastically deforming the end portion of 5b. The inner ring 6 and the balls 3 and 4 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC up to the core part by quenching.

  The hub wheel 5 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner raceway surface 5a and the base portion 7c on the inner side of the wheel mounting flange 7 to the small diameter step portion 5b. Thus, the surface hardness is set to a range of 58 to 64 HRC by induction hardening. The caulking portion 5c 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 7, the fretting resistance of the small-diameter step portion 5b serving as the fitting portion of the inner ring 6 is improved, and the minute There is no occurrence of cracks and the like, and the plastic working of the caulking portion 5c 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 5a of the hub wheel 5 on the inner circumference. The surface 2a and the inner side outer rolling surface 2b facing the inner rolling surface 6a of the inner ring 6 are integrally formed. A double row of balls 3 and 4 is accommodated between these rolling surfaces, and is held by the cages 9 and 10 so as to roll freely.

  This outer member 2 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 2a and 2b have a surface hardness in the range of 58 to 64HRC by induction hardening. Has been cured. Seals 11 and 12 are attached to the opening of the annular space formed between the outer member 2 and the inner member 1, and leakage of grease sealed inside the bearing and rainwater from the outside. And dust are prevented from entering the bearing.

  In the present embodiment, the pitch circle diameter PCDo of the outer side balls 3 group is set larger than the pitch circle diameter PCDi of the inner side balls 4 group. Along with this, the inner rolling surface 5a of the hub wheel 5 is enlarged in diameter than the inner rolling surface 6a of the inner ring 6, and the outer rolling surface 2a on the outer side of the outer member 2 is also rolled on the inner side. The diameter is larger than that of the surface 2b. The number of balls in the outer-side balls 3 group is set to be larger than the number of balls in the inner-side balls 4 group, and the ball diameter do in the outer-side balls 3 group is set to be larger in the inner-side balls 4 group. The diameter is set larger than the ball diameter di. Thus, each pitch circle diameter PCDo, PCDi is set to PCDo> PCDi, the number of balls in the outer side ball 3 group is set larger than the number of balls in the inner side ball 4 group, and the outer side Since the ball diameter do in the third group of balls is set to be larger than the ball diameter di in the fourth group of balls on the inner side, the bearing rigidity is improved and the life of the wheel bearing device can be extended. .

  The outer shape of the hub wheel 5 includes a stepped portion 8a formed in a tapered shape via a counter portion 13 from the groove bottom portion of the inner rolling surface 5a, and a shaft-shaped portion 8 extending in the axial direction from the counter portion 13, and an inner ring. 6 continues to the small-diameter step portion 5b through the shoulder portion 8b that is abutted. A mortar-shaped recess 14 is formed at the outer end of the hub wheel 5. The depth of the recess 14 is a depth extending beyond the groove bottom of the inner rolling surface 5a to the vicinity of the shaft-like portion, and the outer side of the hub wheel 5 is formed to have a substantially uniform thickness.

  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. From the running surface 2a through the cylindrical shoulder portion 15 and the step portion 15a formed in an arc shape, the cylindrical shoulder portion 16 is continued to the outer side rolling surface 2b on the inner side. And it forms so that the groove bottom diameter of this outer side rolling surface 2b and the internal diameter of the shoulder part 15 of a large diameter side may become substantially the same diameter.

  In the wheel bearing device having such a configuration, the pitch circle diameter PCDo of the outer three balls group is formed larger than the pitch circle diameter PCDi of the inner four balls group. The number of balls in the outer side balls 3 group is set larger than the number of balls in the inner side balls 4 group, and the ball diameter do of the outer side balls 3 group is set to the ball diameter di of the inner side balls 4 group. The knuckle size can be reduced, the device can be made lighter and more compact, and the bearing rigidity of the outer side can be increased compared to the inner side, resulting in a longer bearing length. Life can be extended. Furthermore, since the recess 14 is formed along the outer shape at the outer end of the hub wheel 5 and the outer side of the hub wheel 5 is set to a uniform thickness, the device is lighter, more compact and more rigid. It is possible to solve the conflicting problem.

  FIG. 2 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 components and site | parts which have the same components same site | part or the same function as embodiment mentioned above, and detailed description is abbreviate | omitted.

  This wheel bearing device is for a driven wheel called a third generation, and includes an inner member 17 and an outer member 18, and a double row tapered roller 19 accommodated between the members 17 and 18 so as to roll freely. , 20 groups. The inner member 17 includes a hub ring 21 and an inner ring 22 that is press-fitted into the hub ring 21 via a predetermined shimiro.

  The hub wheel 21 integrally has a wheel mounting flange 7 for mounting a wheel (not shown) at one end portion, one (outer side) tapered inner rolling surface 21a on the outer periphery, and this inner rolling. A small-diameter step portion 5b is formed through an axial portion 8 extending in the axial direction from the surface 21a. A large collar for guiding the tapered roller 19 is not formed on the large diameter side of the inner rolling surface 21a of the hub wheel 21, and a large collar 23 is formed on the outer member 18 described later. Further, a small flange for holding the tapered roller 19 is not formed on the small diameter side of the inner rolling surface 21a, and the inner rolling is smoothly performed from the inner side base portion 7c of the wheel mounting flange 7 formed in an arc shape. The running surface 21a continues, and reaches the shoulder portion 8b and the small diameter step portion 5b via the axial portion 8 and the arc-shaped step portion 8a extending in the axial direction from the small diameter side of the inner rolling surface 21a. By adopting such a configuration, not only forging and cutting of the hub wheel 21 can be facilitated, but stress concentration generated in the hub wheel 21 can be alleviated, and strength and durability can be improved.

  The other (inner side) tapered inner rolling surface 22a is formed on the outer periphery of the inner ring 22, and a large flange 22b for guiding the tapered roller 20 to the large diameter side of the inner rolling surface 22a, and a small diameter side Small scissors 22c are formed for preventing the tapered rollers 20 from falling off. The inner ring 22 is press-fitted into the small-diameter step portion 5b of the hub wheel 21 through a predetermined shimiro, and a predetermined bearing preload is applied by a caulking portion 5c formed by plastically deforming an end portion of the small-diameter step portion 5b. Is fixed in the axial direction. As a result, it is possible to provide a self-retaining structure that achieves light weight and compactness and that maintains the initially set preload for a long period of time.

  The outer member 18 integrally has a vehicle body mounting flange 2 c on the outer periphery, an outer tapered outer rolling surface 18 a facing the inner rolling surface 21 a of the hub wheel 21 on the inner periphery, and an inner side of the inner ring 22. A tapered outer rolling surface 18b on the inner side facing the rolling surface 22a is integrally formed. In this embodiment, the outer member 18 is provided with a large collar 23 for guiding the outer side tapered roller 19. That is, a large collar 23 that abuts against the large end surface of the tapered roller 19 and guides the tapered roller 19 is integrally provided on the outer diameter side of the outer side outer rolling surface 18 a of the outer member 18. As a result, the stress concentration on the hub wheel 21 with respect to the load applied via the tapered roller 19 is alleviated, and even if a large moment load is applied to the wheel mounting flange 7, the hub wheel 21 is not easily fatigued. -Durability can be ensured.

  The outer member 18 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the outer surface 18a, 18b of the large flange 23 and the double row has a surface hardness of 58 to 58 by induction hardening. Hardened to a range of 64 HRC. And the double-row tapered rollers 19 and 20 group are accommodated so that rolling is possible between the rolling surfaces 18a, 21a and 18b, 22a via the holders 24 and 25, respectively. In addition, a seal 11 and a slinger 26 are attached to the opening of the annular space formed between the outer member 18 and the inner member 17, and leakage of grease sealed inside the bearing to the outside, Rain water and dust are prevented from entering the bearing. A magnetic encoder is integrally joined to the outer slinger 26.

  Further, the hub wheel 21 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner rolling surface 21a and the shaft from the base portion 7c of the wheel mounting flange 7 with which the outer seal 11 is in sliding contact. The surface hardness of the step portion 8, the step portion 8 a, the shoulder portion 8 b, and the small-diameter step portion 5 b is subjected to a hardening process within a range of 58 to 64 HRC by induction hardening. Further, the inner ring 22 and the tapered rollers 19 and 20 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core part by quenching.

  In this embodiment, the pitch circle diameter PCDo of the outer side tapered rollers 20 group is set larger than the pitch circle diameter PCDi of the inner side tapered rollers 19 group, and the number of rollers of the outer side tapered rollers 19 group is set. Is set to be larger than the number of rollers of the inner side tapered roller 20 group, and the roller diameter Do of the outer side tapered roller 19 group is larger than the roller diameter Di of the inner side tapered roller 20 group, and The roller length Lo of the outer side tapered roller 19 group is set longer than the roller length Li of the inner side tapered roller 20 group. As a result, the inner side of the outer member 18 can be made more compact, the apparatus can be made lighter and more compact, and the bearing rigidity of the outer side portion can be further increased compared to the inner side while suppressing an increase in weight. This can extend the life of the bearing. The roller length Li of the inner tapered roller group 20 can be set longer than the roller length Lo of the outer tapered roller group 19 according to the inner bearing space, and the inner bearing rigidity can be increased. You can also.

Here, a mortar-like recess 14 is formed at the outer end of the hub wheel 21 by forging. The depth of the recess 14 extends from the inner rolling surface 21a to the vicinity of the stepped portion 8a , and the outer end of the hub wheel 21 is formed to have a substantially uniform thickness. As a result, it is possible to simultaneously solve the conflicting problems of the light weight, compactness, and high rigidity of the apparatus.

  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 third-generation wheel bearing device for a driven wheel.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. 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, 17 ... Inner member 2, 18 ... Outer member 3, 4, ... Ball 5, 21... Hub wheels 5a, 6a, 21a, 22a .. Inner rolling surface 5b ... Small diameter step 5c ... ································································ 6 Hub bolt 7b ... Round hole 7c ... Base 8 ... ······· Shafts 8a, 15a ········ Steps 8b ············· Shoulders 9, 10, 24, 25 ..Cage 11, 12 ... Seal 13 ... Counter section 4 ... Recess 15 ... The shoulder 16 on the large diameter side ... Small diameter side shoulders 19, 20... Tapered rollers 22b, 23... ... Slinger 50 ... ... Wheel 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 wheels 52a, 54a ····· Inner rolling surface 52b ········· Small diameter Stepped part 52c ..... caulking part 53 ... ... Wheel mounting flange 54 ... Inner ring 55 ... Inner members 56, 57 ... · Balls 58, 59 ··········· Retainer 60, 61 ······· Seal D1 ·············· Pitch circle diameter D2 ......... Pitch circle diameter Di of the inner side ball ......... Inner side tapered roller diameter Do ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Diameter of outer tapered roller di ・ ・ ・ ・ ・ ・ ・ ・ Ball diameter of inner ball do ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・-Outer side ball diameter Li ... Length of inner side tapered roller Lo ... Length of outer side tapered roller PCDi・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter PCDo of inner side rolling element ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter of outer side rolling element

Claims (5)

An outer member having a double row outer raceway formed on the inner periphery;
It has a wheel mounting flange for mounting a wheel at one end, and has one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a shaft-shaped portion from the inner rolling surface via the shaft-shaped portion. A hub ring having a small-diameter step portion extending in the axial direction, and an inner ring press-fitted into the small-diameter step portion of the hub ring and having the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery An inner member comprising:
A double row rolling element group accommodated so as to be freely rollable between both rolling surfaces of the inner member and the outer member,
A wheel in which the pitch circle diameter of the rolling element group closer to the wheel mounting flange in the double row rolling element group is set larger than the pitch circle diameter of the rolling element group far from the wheel mounting flange. Bearing device for
A stepped portion is formed between the shaft-shaped portion of the hub wheel and a shoulder portion that is abutted against the inner ring, and a mortar-shaped recess is formed at the outer end of the hub wheel. Is deeper than the groove bottom of the inner raceway surface of the hub wheel and near the stepped portion, and the rolling element size of the rolling element group closer to the wheel mounting flange is far from the wheel mounting flange. A wheel bearing device characterized in that it is larger than the rolling element size of the side rolling element group and the number of rolling elements is set to be large.   The wheel bearing device according to claim 1, wherein the rolling elements are balls.   The rolling element is a tapered roller, and the roller diameter of the tapered roller group on the side close to the wheel mounting flange is larger than the roller diameter of the tapered roller group on the side far from the wheel mounting flange, and the length of the rollers. The wheel bearing device according to claim 1, wherein is set longer.   A large flange for guiding the tapered roller is not formed on the large diameter side of the inner rolling surface of the hub wheel, and the large flange is formed on the large diameter side of the outer rolling surface of the outer member. The wheel bearing device according to claim 3. The wheel bearing device according to any one of claims 1 to 4, wherein the outer shape of the hub wheel is formed so as to have a substantially uniform thickness corresponding to the recess.

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