Bearing device for wheel

Abstract

Provided is a bearing device for a wheel, the bearing device being capable of improving rigidity and achieving further weight reduction. A wheel bearing device (1) is provided with: an outer ring (2) having two rows of outer raceway surfaces (23, 24); inner members (a hub ring (3) and an inner ring (4)) having double rows of inner raceway surfaces (33, 41) facing the double rows of outer raceway surfaces (23, 24); and a double-row ball row (5, 6) which is housed so as to be able to roll between the outer ring (2) and both raceway surfaces of the inner member, in which the pitch diameter b of the balls (7) in the ball row (5, 6) and the pitch a between the balls (7) on the outer side and the balls (7) on the inner side in the ball row (5, 6) satisfy the relationship b / a > = 2.0.

Description

Technical Field

[0001] The present invention relates to a wheel bearing device. Background Art

[0002] Conventionally, there is known a wheel bearing device for rotatably supporting a wheel in a suspension device of a vehicle such as an automobile.

[0003] Among vehicles using wheel bearing devices, it is expected that electric vehicles will become more popular, but since electric vehicles are equipped with batteries, there is a tendency for the vehicle weight to increase, and the wheel bearing devices used in electric vehicles also need to be enlarged to increase rigidity. However, if only the wheel bearing device is enlarged, there is a problem of increased weight of the wheel bearing device.

[0004] Therefore, as disclosed in Patent Document 1, in a wheel bearing device including a double-row rolling element group clamped between an outer ring raceway surface of an outer ring member and an inner ring raceway surface of an inner ring member, the pitch circle diameter of the rolling element group on the outer side is set larger than the pitch circle diameter of the rolling element group on the inner side, thereby suppressing the increase in weight and achieving upsizing.

[0005] Prior Art Literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 4206716 Summary of the invention

[0008] Problems to be solved by the invention

[0009] On the other hand, in the wheel bearing device, the radial dimension is made larger and the axial dimension is made smaller, thereby achieving increased rigidity and reduced weight.

[0010] However, in the wheel bearing device described in Patent Document 1, no consideration is given to optimizing the radial size and the axial size, and there is a limit to the weight reduction of the wheel bearing device.

[0011] The present invention has been made in view of the above-mentioned circumstances, and provides a wheel bearing device capable of improving rigidity and achieving further weight reduction.

[0012] Means for solving problems

[0013] That is, a wheel bearing device comprises: an outer member having a double-row outer raceway surface on its inner circumference; an inner member having a double-row inner raceway surface opposite to the double-row outer raceway surface; and double-row rolling elements which are freely accommodated between the two raceway surfaces of the outer member and the inner member, wherein a pitch circle diameter b of the double-row rolling elements and a spacing a between rolling elements on one axial side and the other axial side of the double-row rolling elements satisfy the relationship of b / a≥2.0.

[0014] Effects of the Invention

[0015] According to the present invention, the rigidity of the wheel bearing device can be improved and the weight of the wheel bearing device can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a side cross-sectional view showing a wheel bearing device.

[0017] Figure 2 It is a side cross-sectional view showing the outer side sealing member.

[0018] Figure 3 It is a side cross-sectional view showing a wheel bearing device according to a second embodiment.

[0019] Figure 4 It is a side cross-sectional view showing an outer side sealing member of a wheel bearing device according to a second embodiment.

[0020] Figure 5 It is a side cross-sectional view showing a wheel bearing device according to a third embodiment.

[0021] Figure 6 It is a side cross-sectional view showing the wall thickness of a portion where a recessed portion of a hub wheel is formed in a wheel bearing device according to a third embodiment. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments for implementing the present invention will be described using the drawings.

[0023] [Wheel bearing device]

[0024] Figure 1 The wheel bearing device 1 shown is one embodiment of the wheel bearing device of the present invention, and rotatably supports a wheel in a suspension device of a vehicle such as an automobile. The wheel bearing device 1 is configured as a wheel bearing device for a drive wheel.

[0025] In the following description, the axial direction refers to the direction along the rotation axis X of the wheel bearing device 1. In addition, the outer side refers to one side in the axial direction, that is, the wheel side of the wheel bearing device 1 when installed on the vehicle body, and the inner side refers to the other side in the axial direction, that is, the vehicle body side of the wheel bearing device 1 when installed on the vehicle body.

[0026] The wheel bearing device 1 has a structure called the third generation, including an outer ring 2 as an outer member, a hub ring 3 and an inner ring 4 as inner members, a double-row inner side ball row 5 and an outer side ball row 6 as rolling rows, an outer side sealing member 9, and an inner side sealing member 10.

[0027] An inner opening 21 into which the inner seal member 10 can be fitted is formed at the inner end of the outer ring 2. An outer opening 22 into which the outer seal member 9 can be fitted is formed at the outer end of the outer ring 2.

[0028] The inner side sealing member 10 is fitted into the inner side opening 21, thereby sealing the inner side opening end of the annular space S formed by the outer ring 2 as the outer member and the hub ring 3 and the inner ring 4 as the inner members. The outer side sealing member 9 is fitted into the outer side opening 22, thereby sealing the outer side opening end of the annular space S.

[0029] The inner side sealing member 10 and the outer side sealing member 9 are sealing devices that seal the open end of the annular space S. In this way, the inner side sealing member 10 and the outer side sealing member 9 seal the inner and outer open ends of the annular space S, thereby preventing foreign matter such as muddy water from intruding into the interior of the wheel bearing device 1.

[0030] An inner outer raceway surface 23 and an outer outer raceway surface 24 are formed on the inner circumferential surface of the outer ring 2. A vehicle body mounting flange 25 for mounting the outer ring 2 to a vehicle body side member is integrally formed on the outer circumferential surface of the outer ring 2. The vehicle body mounting flange 25 is provided with bolt holes 26 for inserting fastening members (here, bolts) for fastening the vehicle body side member and the outer ring 2.

[0031] A small-diameter step portion 31 having a smaller diameter than that of the outer end is formed at the inner end of the outer peripheral surface of the hub wheel 3. A wheel mounting flange 32 for mounting a wheel is integrally formed at the outer end of the hub wheel 3.

[0032] The wheel mounting flange 32 is an example of a flange extending radially outward from one axial end of the inner member. A plurality of bolt holes 35 are formed in the wheel mounting flange 32. Hub bolts 36 for fastening the hub 3 and the wheel or brake components can be press-fitted into the bolt holes 35.

[0033] In the hub 3, a sliding contact surface 34 is formed on the base side of the wheel mounting flange 32, which is in sliding contact with the outer side sealing member 9. An inner side track surface 33 on the outer side is provided on the outer peripheral surface of the hub 3 in a manner opposed to the outer side track surface 24 on the outer side of the outer ring 2. That is, the inner side track surface 33 is formed by the hub 3 on the outer side of the inner member.

[0034] An axial hole 37 formed along the axial direction is formed in the inner diameter portion of the hub wheel 3. The axial hole 37 penetrates the hub wheel 3 along the axial direction, and the shaft portion of the constant velocity universal joint can be connected to the axial hole 37.

[0035] The inner ring 4 is provided on the small-diameter step portion 31 of the hub ring 3. The inner ring 4 is fixed to the small-diameter step portion 31 of the hub ring 3 by press-fitting. An inner side inner track surface 41 is provided on the outer peripheral surface of the inner ring 4 so as to be opposed to the outer track surface 23 on the inner side of the outer ring 2. That is, the inner side track surface 41 is formed by the inner ring 4 on the inner side of the inner member.

[0036] The inner ball row 5 and the outer ball row 6 as rolling rows are composed of a plurality of balls 7 as rolling bodies held by a retainer 8. The inner ball row 5 is freely sandwiched between the inner raceway surface 41 of the inner ring 4 and the outer raceway surface 23 on the inner side of the outer ring 2. The outer ball row 6 is freely sandwiched between the inner raceway surface 33 of the hub ring 3 and the outer raceway surface 24 on the outer side of the outer ring 2. That is, the inner ball row 5 and the outer ball row 6 are freely accommodated between the two raceway surfaces of the outer member and the inner member.

[0037] In the wheel bearing device 1, a double row angular contact ball bearing is formed by the outer ring 2, the hub ring 3 and the inner ring 4, the inner ball row 5 and the outer ball row 6. It should be noted that the wheel bearing device 1 may also be formed by a double row tapered roller bearing instead of a double row angular contact ball bearing.

[0038] like Figure 2 As shown, the outer sealing member 9 includes a core metal 91 and an elastic member 92. The core metal 91 is formed of, for example, a steel plate in a cylindrical shape, and is fitted in the outer opening portion 22 of the outer ring 2 at its inner diameter.

[0039] The elastic member 92 is made of, for example, synthetic rubber and is fixed to the core metal 91 by vulcanization bonding. The elastic member 92 includes: a base 92a, which is vulcanized and bonded to the core metal 91; and a grease lip 92b, a first side lip 92c, and a second side lip 92d, which extend from the base 92a and are respectively formed in an annular shape. The grease lip 92b, the first side lip 92c, and the second side lip 92d are in sliding contact with the sliding contact surface 34 of the hub 3.

[0040] The outer sealing member 9 is located on the inner diameter side of the outer opening 22 and does not protrude toward the outer diameter side from the outer peripheral surface 27 on the axial end side of the outer ring 2 .

[0041] [Relationship between the pitch diameter of the ball and the pitch between the balls in the wheel bearing device 1]

[0042] The balls 7 constituting the inner ball row 5 and the balls 7 constituting the outer ball row 6 are arranged so that the inter-ball spacing in the axial direction is a. The inter-ball spacing a is the distance in the axial direction between the center P1 of the ball 7 in the inner ball row 5 and the center P2 of the ball 7 in the outer ball row 6. The inter-ball spacing a is an example of the inter-rolling element spacing a.

[0043] The pitch circle diameter of the balls 7 constituting the inner ball row 5 and the pitch circle diameter of the balls 7 constituting the outer ball row 6 are formed to be the same size. The pitch circle diameter of the balls 7 constituting the inner ball row 5 and the outer ball row 6 is b.

[0044] The pitch circle diameter b is the diameter of a circle that is centered on the rotation axis X and passes through the center P1 of the ball 7 in the inner ball row 5. In addition, the pitch circle diameter b is the diameter of a circle that is centered on the rotation axis X and passes through the center P2 of the ball 7 in the outer ball row 6. The pitch circle diameter b of the ball 7 is an example of the pitch circle diameter b of the rolling body.

[0045] The hub bolt 36 press-fitted into the bolt hole 35 of the wheel mounting flange 32 has a pitch circle diameter c. The pitch circle diameter c is the diameter of a circle having the rotation axis X as the center and passing through the center P3 of the hub bolt 36 .

[0046] In the wheel bearing device 1 , the ratio (b / a) of the pitch diameter b to the inter-ball pitch a is set to be greater than or equal to 2.0. That is, the pitch diameter b and the inter-ball pitch a are set to satisfy the relationship of b / a≥2.0.

[0047] By setting the pitch diameter b and the spacing a between the balls to b / a≥2.0, the radial size of the wheel bearing device 1 can be made larger, and the axial size of the wheel bearing device 1 can be made smaller while preventing the retainer 8 of the inner side ball row 5 from interfering with the retainer 8 of the outer side ball row 6. As a result, the radial size and axial size of the wheel bearing device 1 can be optimized, the rigidity and life of the wheel bearing device 1 can be improved, and the wheel bearing device 1 can be made lighter.

[0048] In addition, in the wheel bearing device 1, when the pitch circle diameter c of the hub bolt 36 is set to 100, the ratio (b / a) of the pitch circle diameter b to the inter-ball spacing a is preferably set to 3.6 or less. That is, the pitch circle diameter b when the pitch circle diameter c is set to 100 and the inter-ball spacing a are preferably set to satisfy the relationship of b / a≤3.6.

[0049] In such a setting, as shown in Table 1, for example, when the pitch circle diameter c of the hub bolt 36 is 100 mm, the pitch circle diameter b and the inter-ball spacing a can be set to satisfy the relationship of b / a≤3.6. In this case, when the pitch circle diameter c is set to 100, "b / a" is "≤3.6", and the pitch circle diameter b and the inter-ball spacing a satisfy the relationship of b / a≤3.6.

[0050] In addition, when the pitch circle diameter c of the hub bolt 36 is 114.3 mm, the pitch circle diameter b and the inter-ball spacing a can be set to satisfy the relationship of b / a≤4.1. In this case, when the pitch circle diameter c of 114.3 mm is converted to 100 mm and the pitch circle diameter c is set to 100, "b / a" is "≤3.59", and the pitch circle diameter b and the inter-ball spacing a satisfy the relationship of b / a≤3.6.

[0051] Furthermore, when the pitch circle diameter c of the hub bolt 36 is 120 mm, the pitch circle diameter b and the inter-ball spacing a can be set to satisfy the relationship of b / a≤4.3. In this case, when the pitch circle diameter c of 120 mm is converted to 100 mm and the pitch circle diameter c is set to 100, "b / a" is "≤3.58", and the pitch circle diameter b and the inter-ball spacing a satisfy the relationship of b / a≤3.6.

[0052] [Table 1]

[0053]

[0054] In this way, by setting the pitch circle diameter b and the ball spacing a to satisfy the relationship of b / a≤3.6 when the pitch circle diameter c is set to 100, it is possible to suppress the interference between the hub bolt 36 and the outer ring 2 and the situation that the hub bolt 36 is prevented from being pulled out from the wheel mounting flange 32 when the wheel bearing device 1 is enlarged. As a result, the rigidity of the wheel bearing device 1 can be improved while maintaining the replaceability of the hub bolt 36, and the wheel bearing device 1 can be further lightweight.

[0055] [Second Embodiment of Wheel Bearing Device]

[0056] The wheel bearing device 1 can also be Figure 3The wheel bearing device 1A is different from the wheel bearing device 1 in that an outer side sealing member 19 is provided instead of the outer side sealing member 9. The wheel bearing device 1A is configured as a wheel bearing device for a drive wheel.

[0057] like Figure 4 As shown, the outer sealing member 19 includes a core metal 191 and an elastic member 192. The core metal 191 is formed of, for example, a steel plate in a cylindrical shape, and is fitted in the outer opening portion 22 of the outer ring 2 at its inner diameter.

[0058] The elastic member 192 is made of, for example, synthetic rubber and is fixed to the core metal 191 by vulcanization bonding. The elastic member 192 includes: a base 192a, which is vulcanized and bonded to the core metal 191; a grease lip 192b, a first side lip 192c, and a second side lip 192d, which extend from the base 192a and are respectively formed in an annular shape; and a weir portion 192e, which protrudes toward the outer diameter side than the outer peripheral surface 27 at the outer side end of the outer ring 2.

[0059] The grease lip 192b, the first side lip 192c, and the second side lip 192d are in sliding contact with the sliding contact surface 34 of the hub wheel 3. The outer diameter of the weir portion 192e is fitted to the outer peripheral surface 27 of the outer ring 2.

[0060] Thus, in the outer side sealing member 19, the weir portion 192e is located at a position closer to the outer diameter side than the outer peripheral surface 27 at one axial end side of the outer ring 2, and the outer side sealing member 19 protrudes toward the outer diameter side than the outer peripheral surface 27. The other structures of the wheel bearing device 1A are the same as those of the wheel bearing device 1, and therefore the same reference numerals are given and the description thereof is omitted.

[0061] [Relationship between the Pitch Circle Diameter of the Ball and the Inter-Ball Pitch in the Wheel Bearing Device 1A]

[0062] In the wheel bearing device 1A, the ratio (b / a) of the pitch diameter b to the inter-ball pitch a is set to be greater than 2.0, similarly to the wheel bearing device 1. That is, the pitch diameter b and the inter-ball pitch a are set to satisfy the relationship b / a≥2.0.

[0063] By setting the pitch diameter b and the inter-ball spacing a to b / a≥2.0, the radial size of the wheel bearing device 1A can be made larger, and the axial size can be made smaller while preventing the retainer 8 of the inner side ball row 5 from interfering with the retainer 8 of the outer side ball row 6. Thus, the radial size and axial size of the wheel bearing device 1A can be optimized, the rigidity and life of the wheel bearing device 1A can be improved, and the wheel bearing device 1 can be made lighter.

[0064] In addition, in the wheel bearing device 1A, when the pitch circle diameter c of the hub bolt 36 is set to 100, the ratio (b / a) of the pitch circle diameter b to the inter-ball spacing a is preferably set to 3.2 or less. That is, the pitch circle diameter b when the pitch circle diameter c is set to 100 and the inter-ball spacing a are preferably set to satisfy the relationship of b / a≤3.2.

[0065] In such a setting, as shown in Table 2, for example, when the pitch circle diameter c of the hub bolt 36 is 100 mm, the pitch circle diameter b and the inter-ball spacing a can be set to satisfy the relationship of b / a≤3.2. In this case, when the pitch circle diameter c is set to 100, "b / a" is "≤3.2", and the pitch circle diameter b and the inter-ball spacing a satisfy the relationship of b / a≤3.2.

[0066] In addition, when the pitch circle diameter c of the hub bolt 36 is 114.3 mm, the pitch circle diameter b and the inter-ball spacing a can be set to satisfy the relationship of b / a≤3.7. In this case, when the pitch circle diameter c of 114.3 mm is converted to 100 mm and the pitch circle diameter c is set to 100, "b / a" is "≤3.24", and the pitch circle diameter b and the inter-ball spacing a satisfy the relationship of b / a≤3.2.

[0067] Furthermore, when the pitch circle diameter c of the hub bolt 36 is 120 mm, the pitch circle diameter b and the inter-ball spacing a can be set to satisfy the relationship of b / a≤3.9. In this case, when the pitch circle diameter c of 120 mm is converted to 100 mm and the pitch circle diameter c is set to 100, "b / a" is "≤3.25", and the pitch circle diameter b and the inter-ball spacing a satisfy the relationship of b / a≤3.2.

[0068] [Table 2]

[0069]

[0070] In this way, by setting the pitch circle diameter b and the inter-ball spacing a to satisfy the relationship of b / a≤3.2 when the pitch circle diameter c is set to 100, when the wheel bearing device 1 is enlarged in diameter, it is possible to prevent the hub bolt 36 from interfering with the weir portion 192e protruding toward the outer diameter side than the outer peripheral surface 27 of the outer ring 2 and hindering the hub bolt 36 from being pulled out of the wheel mounting flange 32. As a result, the rigidity of the wheel bearing device 1A can be improved while maintaining the replaceability of the hub bolt 36, and the wheel bearing device 1A can be further lightweight.

[0071] [Third Embodiment of Wheel Bearing Device]

[0072] The wheel bearing device 1 can also be Figure 5The wheel bearing device 1B is configured as a wheel bearing device for a driven wheel, and is different from the wheel bearing device 1 mainly in that a hub wheel 13 is provided instead of the hub wheel 3 .

[0073] A small-diameter step portion 131 having a smaller diameter than the outer end portion is formed at the inner end portion of the outer peripheral surface of the hub wheel 13. A wheel mounting flange 132 for mounting a wheel is integrally formed at the outer end portion of the hub wheel 13.

[0074] The wheel mounting flange 132 is an example of a flange extending radially outward from one axial end of the inner member. A plurality of bolt holes 135 are formed in the wheel mounting flange 132. Hub bolts 136 for fastening the hub 13 to the wheel or brake components can be press-fitted into the bolt holes 135.

[0075] The hub 13 has a sliding contact surface 134 formed at the base of the wheel mounting flange 132 for sliding contact with the outer sealing member 9. The hub 13 has an outer inner raceway surface 133 disposed on the outer peripheral surface 138 thereof so as to face the outer raceway surface 24 of the outer ring 2.

[0076] A recessed portion 137 is formed in the inner diameter portion of the hub ring 13, which is recessed from the outer side end in the axial direction toward the inner side end. The recessed portion 137 is formed in the axial direction to a position between the inner side ball row 5 and the outer side ball row 6. The inner ring 4 is provided in the small diameter step portion 131 of the hub ring 13. The inner side end portion of the hub ring 13 is riveted to the inner side end surface of the inner ring 4, and the inner ring 4 is fixed to the small diameter step portion 131 of the hub ring 13 by press fitting and riveting.

[0077] The hub ring 13 has an inclined surface 139 in the axial direction between the inner raceway surface 133 and the outer peripheral surface 138 on the inner side of the inner raceway surface 133. The hub ring 13 has a heat treatment hardened layer R, which reaches the outer peripheral surface 138 from the portion where the sliding contact surface 134 is formed, through the portion where the inner raceway surface 133 is formed and the portion where the inclined surface 139 is formed.

[0078] In the wheel bearing device 1B, the inner side sealing member 10 is not fitted into the inner side opening 21 of the outer ring 2, but a cover 15 is fitted to close the inner side opening 21. The other structures of the wheel bearing device 1B are the same as those of the wheel bearing device 1, so the same reference numerals are given and the description is omitted.

[0079] [Relationship between the pitch diameter of the ball and the pitch between the balls in the wheel bearing device 1B]

[0080] In the wheel bearing device 1B, the ratio (b / a) of the pitch diameter b to the inter-ball pitch a is set to be greater than 2.0, similarly to the wheel bearing device 1. That is, the pitch diameter b and the inter-ball pitch a are set to satisfy the relationship b / a≥2.0.

[0081] By setting the pitch diameter b and the inter-ball spacing a to b / a≥2.0, the radial size of the wheel bearing device 1B can be made larger, and the axial size can be made smaller while preventing the retainer 8 of the inner side ball row 5 from interfering with the retainer 8 of the outer side ball row 6. As a result, the radial size and axial size of the wheel bearing device 1B can be optimized, the rigidity and life of the wheel bearing device 1B can be improved, and the wheel bearing device 1B can be made lighter.

[0082] [Shape of Hub Ring in Wheel Bearing Device 1B]

[0083] The recess 137 of the hub ring 13 is formed along the outer shape of the hub ring 13, the wall thickness between the sliding contact surface 134 in the hub ring 13 and the inner circumferential surface of the recess 137 is d1, the wall thickness between the inner track surface 133 in the hub ring 13 and the inner circumferential surface of the recess 137 is e1, and the wall thickness between the inclined surface 139 in the hub ring 13 and the inner circumferential surface of the recess 137 is f1.

[0084] It should be noted that the wall thickness d1 is represented by the shortest distance between the sliding contact surface 134 and the inner circumferential surface of the recess 137 , the wall thickness e1 is represented by the shortest distance between the inner track surface 133 and the inner circumferential surface of the recess 137 , and the wall thickness f1 is represented by the shortest distance between the inclined surface 139 and the inner circumferential surface of the recess 137 .

[0085] like Figure 6 As shown, the depth of the heat treatment hardened layer R of the portion of the hub ring 13 where the sliding contact surface 134 is formed is d2, the depth of the heat treatment hardened layer R of the portion of the hub ring 13 where the inner raceway surface 133 is formed is e2, and the depth of the heat treatment hardened layer R of the portion of the hub ring 13 where the inclined surface 139 is formed is f2.

[0086] In the wheel bearing device 1B, the wall thickness d1 between the sliding contact surface 134 and the inner peripheral surface of the recess 137 is formed to be more than twice the thickness of the depth d2 of the heat treatment hardened layer R of the portion where the sliding contact surface 134 is formed, the wall thickness e1 between the inner raceway surface 133 and the inner peripheral surface of the recess 137 is formed to be more than twice the thickness of the depth e2 of the heat treatment hardened layer R of the portion where the inner raceway surface 133 is formed, and the wall thickness f1 between the inclined surface 139 and the inner peripheral surface of the recess 137 is formed to be more than twice the thickness of the depth f2 of the heat treatment hardened layer R of the portion where the inclined surface 139 is formed.

[0087] In addition, the wall thickness d1 between the sliding contact surface 134 and the inner circumferential surface of the recess 137, the wall thickness e1 between the inner track surface 133 and the inner circumferential surface of the recess 137, and the wall thickness f1 between the inclined surface 139 and the inner circumferential surface of the recess 137 are set so that the difference between the wall thickness d1, the wall thickness e1, and the wall thickness f1 is 5 mm or less. It should be noted that the difference between the wall thickness d1, the wall thickness e1, and the wall thickness f1 refers to the difference between the maximum value and the minimum value of the wall thickness d1, the wall thickness e1, and the wall thickness f1. That is, the wall thickness d1, the wall thickness e1, and the wall thickness f1 are set to have a difference of 5 mm or less, and become approximately uniform in size. In addition, the wall thickness d1 and the wall thickness e1 are set to have a difference of 5 mm or less, and the wall thickness e1 and the wall thickness f1 are set to have a difference of 5 mm or less.

[0088] In this way, in the wheel bearing device 1B, since the recess 137 is formed in the hub ring 13, the wheel bearing device 1B can be lightweight. In this case, the wall thickness d1, e1, and f1 of the hub ring 13 are formed to be at least twice the depth f2 of the heat treatment hardened layer R, so the rigidity of the hub ring 13 can be ensured. In addition, if the wall thickness d1, the wall thickness e1, and the wall thickness f1 in the hub ring 13 are formed to be approximately uniform in size, the fiber flow based on the forging process of the hub ring 13 is well formed along the inner track surface 133 and toward the wheel mounting flange 132 side, so the life of the wheel bearing device 1B can be improved.

[0089] It should be noted that, in the hub ring 13, the recess 137 is sometimes formed only in the portion that is axially closer to the outside than the inclined surface 139. In this case, the wall thickness d1 between the sliding contact surface 134 and the inner peripheral surface of the recess 137 and the wall thickness e1 between the inner side track surface 133 and the inner peripheral surface of the recess 137 can be set so that the difference between the wall thickness d1 and the wall thickness e1 is less than 5 mm. In this case, the fiber flow based on the forging process of the hub ring 13 is also well formed along the inner side track surface 133, which can improve the life of the wheel bearing device 1B.

[0090] Industrial Applicability

[0091] The present invention can be used in a wheel bearing device.

[0092] Description of reference numerals:

[0093] 1, 1A, 1B wheel bearing device

[0094] 2 Outer ring

[0095] 3. 13 wheel hub

[0096] 4Inner circle

[0097] 5 internal side ball rows

[0098] 6 external side ball rows

[0099] 9, 19 External side sealing member

[0100] 23 (Inner side) Outer track surface

[0101] 24 (outer side) outer track surface

[0102] 27 Outer Surface

[0103] 32, 132 wheel mounting flange

[0104] 33, 133 (outer side) inner track surface

[0105] 35, 135 bolt holes

[0106] 36, 136 wheel hub bolts

[0107] 41 (Inner side) inner track surface

[0108] 134 sliding contact surface

[0109] 137 recess

[0110] 138 outer surface

[0111] 139 inclined surface

[0112] 192e Weir

[0113] a Ball spacing

[0114] b Pitch circle diameter (of the ball)

[0115] c Pitch diameter (of wheel hub bolts)

[0116] d1 Wall thickness (between the sliding contact surface of the hub ring and the inner circumference of the recess)

[0117] d2 Depth of the heat-treated hardened layer (of the portion of the hub wheel that forms the sliding contact surface)

[0118] e1 Wall thickness (between the inner raceway surface of the hub and the inner circumference of the recess)

[0119] e2 Depth of the heat-treated hardened layer (of the portion of the hub wheel where the inner raceway is formed)

[0120] f1 Wall thickness (between the inclined surface of the hub and the inner circumference of the recess)

[0121] f2 Depth of the heat-treated hardened layer (of the portion of the hub where the inclined surface is formed)

[0122] R Heat treatment hardened layer.

Claims

1. A wheel bearing device, comprising: An outer member having a double row of outer track surfaces on the inner periphery; an inner square member having a double-row inner track surface opposite to the double-row outer track surface; and The double-row rolling elements are freely accommodated between the two track surfaces of the outer member and the inner member. It is characterized in that The pitch circle diameter b of the double row rolling elements and the inter-rolling element spacing a between the rolling elements on one axial side and the rolling elements on the other axial side of the double row rolling elements satisfy the relationship of b / a≥2.

0.

2. The wheel bearing device according to claim 1, characterized in that: The wheel bearing device comprises: A flange extending radially outward from one axial end portion of the inner member; hub bolts pressed into bolt holes formed in the flange; and a sealing device that seals an open end of an annular space formed by the outer member and the inner member at one axial end and does not protrude radially outward from an outer peripheral surface of the outer member at one axial end. When the pitch circle diameter c of the hub bolt is set to 100, the pitch circle diameter b of the double row rolling elements and the inter-rolling element spacing a between the rolling elements on one axial side and the rolling elements on the other axial side of the double row rolling elements satisfy the relationship of b / a≤3.

6.

3. The wheel bearing device according to claim 1, characterized in that: The wheel bearing device comprises: A flange extending radially outward from one axial end portion of the inner member; hub bolts pressed into bolt holes formed in the flange; and a sealing device that seals an open end of an annular space formed by the outer member and the inner member at one axial end and has a weir portion that protrudes toward the outer diameter side from the outer peripheral surface of the outer member at one axial end, When the pitch circle diameter c of the hub bolt is set to 100, the pitch circle diameter b of the double row rolling elements and the inter-rolling element spacing a between the rolling elements on one axial side and the rolling elements on the other axial side of the double row rolling elements satisfy the relationship of b / a≤3.

2.

4. The wheel bearing device according to claim 1, characterized in that: The wheel bearing device includes a sealing device for sealing an open end on one axial end side of an annular space formed by the outer member and the inner member. The inner member has a recessed portion that is recessed from one axial end toward the other end and a sliding contact surface with which the sealing device slides. In the inner member, The portion on the axial side where the inner raceway surface is formed and the portion where the sliding contact surface is formed have a heat treatment hardened layer. The wall thickness d1 between the sliding contact surface and the inner peripheral surface of the recessed portion is at least twice the depth d2 of the heat-treated hardened layer of the portion where the sliding contact surface is formed. The wall thickness e1 between the inner raceway surface on one axial side and the inner peripheral surface of the recess is at least twice the depth e2 of the heat treatment hardened layer of the portion where the inner raceway surface is formed. The difference between the wall thickness d1 and the wall thickness e1 is 5 mm or less.

5. The wheel bearing device according to claim 4, characterized in that: The inner member has an inclined surface between the inner raceway surface on one axial side and an outer peripheral surface on the other axial side relative to the inner raceway surface on one axial side. In the inner member, The portion where the inclined surface is formed has a heat-treated hardened layer, The wall thickness f1 between the inclined surface and the inner peripheral surface of the recessed portion is at least twice the depth f2 of the heat treatment hardened layer of the portion where the inclined surface is formed. The difference between the wall thickness f1 and the wall thickness e1 is 5 mm or less.

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