Wheel bearing device

Abstract

The present invention addresses the problem of suppressing movement of a slinger in an axial direction regardless of the resultant axial length of a cylindrical part of the slinger. An outer-side seal member (10) of a wheel bearing device (1) comprises: a slinger (13) that is provided to a base part (3d) of a hub flange (3b) and that has a cylindrical part (13a) which fits into an outer peripheral surface (3j) of a hub ring (3) and a disk part (13b) which faces the hub flange (3b); and a seal member (12) that has a seal lip. The outer peripheral surface (3j) of the hub ring (3) has a fitting part (31) into which the cylindrical part (13a) of the slinger (13) fits. The fitting part (31) has a small-diameter section (311) and a large-diameter section (312) that is positioned farther from the hub flange (3b) than the small-diameter section (311) in the axial direction and that is formed to have a diameter larger than that of the small-diameter section (311).

Description

Wheel bearing device

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

[0002] Conventionally, a wheel bearing device that rotatably supports a wheel in a suspension system of an automobile, etc., is known. The wheel bearing device is provided with a sealing device that closes an open end of an annular space formed by an outer member and an inner member to prevent the intrusion of foreign matter such as muddy water.

[0003] Known sealing devices include, for example, a core bar that is fitted onto the inner periphery of the outer ring, which is the outer member; a seal member that is integrally joined to the core bar and has multiple seal lips; and a slinger that is provided at the base of a hub flange formed on the hub ring, which is the inner member, and has a cylindrical portion that fits onto the outer surface of the hub ring, and a disc portion that is connected to the hub flange side end of the cylindrical portion and faces the hub flange.

[0004] In a sealing device having such a configuration, when the hub wheel is repeatedly subjected to the vehicle turning load and vibrations from the wheel, the received load and vibrations are transmitted to the slinger, which may cause the slinger to move in the axial direction.

[0005] If the slinger moves in the axial direction, the interference of the seal lip that contacts the slinger may change, the slinger may interfere with the rolling elements housed between the raceway surfaces of the outer member and the inner member, or a gap may form between the slinger and the hub flange, allowing water to enter the interior.

[0006] Therefore, in the sealing device for a wheel bearing device disclosed in Patent Document 1, a ring-shaped protrusion is formed on the shoulder of the hub wheel, and the end face of the cylindrical part of the slinger abuts against the protrusion of the hub wheel, thereby suppressing axial movement of the slinger.

[0007] Patent No. 6228756

[0008] However, in the sealing device of Patent Document 1, if the axial length of the cylindrical portion of the slinger is made shorter within the tolerance range, a gap will occur between the end face of the cylindrical portion of the slinger and the convex portion of the hub wheel.

[0009] If a gap occurs between the end face of the cylindrical portion and the convex portion of the hub wheel, the slinger will move axially within the gap, changing the tightening margin of the seal lip, and it will be difficult to prevent a gap from occurring between the slinger and the hub flange, causing water to enter the interior.

[0010] The present invention has been made in consideration of the above-mentioned circumstances, and provides a wheel bearing device that can suppress axial movement of the slinger regardless of the quality of the axial length of the cylindrical portion of the slinger of the sealing device.

[0011] That is, the wheel bearing device comprises an inner member made up of an outer member having a double-row outer raceway on its inner periphery, a hub ring having on its outer periphery one inner raceway facing the outer raceway surface and a hub flange for mounting a wheel, and a raceway surface forming member connected to the hub ring and having on its outer periphery the other inner raceway surface facing the outer raceway surface, double-row rolling elements accommodated so as to be rollable between the raceway surfaces of the outer member and the inner member, and an opening on one axial end side of an annular space formed by the outer member and the inner member. a sealing device that closes the end of the hub flange, the sealing device being provided at the base of the hub flange and comprising a slinger having a cylindrical portion that fits onto the outer peripheral surface of the hub wheel and a disc portion that faces the hub flange, and a seal member having a seal lip, the outer peripheral surface of the hub wheel having a fitting portion into which the cylindrical portion of the slinger fits, the fitting portion having a small diameter portion and a large diameter portion that is positioned axially farther from the hub flange than the small diameter portion and is formed with a larger diameter than the small diameter portion.

[0012] According to the present invention, axial movement of the slinger can be suppressed regardless of the quality of the axial length of the cylindrical portion of the slinger.

[0013] Fig. 1 is a side cross-sectional view showing a wheel bearing device. Fig. 2 is a side cross-sectional view showing a fitting portion of the hub wheel into which an outer seal member and a slinger of the outer seal member are fitted. Fig. 3 is an enlarged side cross-sectional view showing the fitting portion of the hub wheel. Fig. 4 is a diagram showing the relationship between the fitting position of the slinger relative to the fitting portion and the pull-out force of the slinger. Fig. 5 is an enlarged side cross-sectional view showing the fitting portion of the hub wheel according to a second embodiment. Fig. 6 is an enlarged side cross-sectional view showing the fitting portion of the hub wheel according to a third embodiment. Fig. 7 is an enlarged side cross-sectional view showing a cylindrical portion of the slinger according to the second embodiment. Fig. 8 is a side cross-sectional view showing a wheel bearing device of a fourth-generation structure.

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0015] [Wheel Bearing Apparatus] A wheel bearing apparatus 1 shown in FIG. 1 is one embodiment of a wheel bearing apparatus according to the present invention, and supports a wheel rotatably in a suspension system of a vehicle such as an automobile.

[0016] In the following description, the axial direction refers to the direction along the rotation axis X of the wheel support bearing device 1. The outer side refers to one axial end side, which is the wheel side of the wheel support bearing device 1 when attached to the vehicle body, and the inner side refers to the other axial end side, which is the vehicle body side of the wheel support bearing device 1 when attached to the vehicle body.

[0017] The wheel bearing device 1 has a configuration known as a third generation, and includes an outer ring 2 as an outer member, a hub ring 3 and an inner ring 4 as inner members, two rolling rows of inner balls 5 and outer ball rows 6, an inner seal member 9 and an outer seal member 10. The inner ring 4 is an example of a raceway surface forming member connected to the hub ring.

[0018] An inner side opening 2a is formed at the inner side end of the outer ring 2, into which an inner side seal member 9 can be fitted. An outer side opening 2b is formed at the outer side end of the outer ring 2, into which an outer side seal member 10 can be fitted. An inner side outer raceway surface 2c and an outer side outer raceway surface 2d are formed on the inner circumferential surface of the outer ring 2.

[0019] A vehicle body mounting flange 2e for mounting the outer ring 2 to a vehicle body member is integrally formed on the outer peripheral surface of the outer ring 2. The vehicle body mounting flange 2e is provided with bolt holes 2f into which fastening members (here, bolts) for fastening the outer ring 2 to the vehicle body member are inserted.

[0020] The inner end of the outer peripheral surface 3j of the hub wheel 3 is formed with a small-diameter step 3a that is smaller in diameter than the outer end. A hub flange 3b for attaching a wheel is formed integrally with the outer end of the hub wheel 3. A plurality of bolt holes 3e are formed in the hub flange 3b. Hub bolts 3f for fastening the hub wheel 3 to a wheel or brake component are press-fitted into the bolt holes 3e. The hub wheel 3 has a through-hole 3i that passes through in the axial direction, and a constant velocity universal joint, which is an inner member, can be fitted into the through-hole 3i so that it can rotate integrally with the hub wheel 3.

[0021] An outer-side inner raceway surface 3c is provided on the outer peripheral surface 3j of the hub wheel 3 so as to face the outer raceway surface 2d on the outer side of the outer ring 2. In other words, the inner raceway surface 3c is formed on the outer side of the inner member by the hub wheel 3. The inner raceway surface 3c is an example of one of the inner raceways that faces the outer raceway surface.

[0022] The inner seal member 9 is fitted into the inner opening end of the annular space S formed by the outer ring 2 and the hub wheel 3, and closes the inner opening end. The outer seal member 10 is fitted into the outer opening end of the annular space S formed by the outer ring 2 and the hub wheel 3, and closes the outer opening end. The outer seal member 10 is an example of a sealing device.

[0023] An inner ring 4 is provided on the small diameter step 3a of the hub ring 3. The inner ring 4 is fixed to the small diameter step 3a of the hub ring 3 by press fitting and crimping. The inner ring 4 applies preload to the inner ball row 5 and outer ball row 6, which are the rolling rows. The inner ring 4 has an inner end face 4b at its inner end. A crimped portion 3h is formed at the inner end of the hub ring 3, crimped to the inner end face 4b of the inner ring 4.

[0024] An inner-side inner raceway surface 4a is provided on the outer peripheral surface of the inner ring 4 so as to face the inner-side outer raceway surface 2c of the outer ring 2. In other words, the inner raceway surface 4a is formed on the inner side of the inner member by the inner ring 4. The inner raceway surface 4a is an example of the other inner raceway surface facing the outer raceway surface.

[0025] The inner ball row 5 and outer ball row 6, which are rolling rows, are formed by a plurality of balls 7, which are rolling elements, being held in a cage 8. The inner ball row 5 is rollably sandwiched between the inner raceway surface 4a of the inner ring 4 and the inner-side outer raceway surface 2c of the outer ring 2. The outer ball row 6 is rollably sandwiched between the inner raceway surface 3c of the hub ring 3 and the outer-side outer raceway surface 2d of the outer ring 2. In other words, the inner ball row 5 and the outer ball row 6 are rollably housed between the raceway surfaces of the outer member and the inner member.

[0026] In the wheel bearing device 1, a double-row angular contact ball bearing is formed by the outer ring 2, hub ring 3, inner ring 4, inner ball row 5, and outer ball row 6. Note that the wheel bearing device 1 may be formed as a double-row tapered roller bearing instead of the double-row angular contact ball bearing.

[0027] 2, the outer seal member 10 has a core 11 fitted to the inner circumference of the outer end of the outer ring 2, a seal member 12 integrally joined to the core 11, and a slinger 13 fitted to the base 3d of the hub flange 3b of the hub wheel 3. The outer seal member 10 only needs to be fixed to the outer ring 2, which is the outer member, and may, for example, be fitted to the outer periphery of the outer end of the outer ring 2.

[0028] The core metal 11 is made of, for example, a steel plate, and has a cylindrical fitting portion 11a that fits into the inner circumference of the outer side opening 2b of the outer ring 2, and an inner portion 11b that extends from the inner side end of the fitting portion 11a toward the inner diameter side.

[0029] The seal member 12 is formed of an elastic material such as synthetic rubber and is bonded to the core metal 11 by vulcanization bonding. The seal member 12 has a base 12a, a first side lip 12b, a second side lip 12c, and a radial lip 12d. The base 12a is bonded to the inner diameter side end of the inner side surface of the inner portion 11b of the core metal 11, the inner diameter side end face of the inner portion 11b, the outer side surface of the inner portion 11b, and the outer side end of the fitting portion 11a of the core metal 11.

[0030] The first side lip 12b extends from the core 11 toward the hub flange 3b, which is the outer side. Specifically, the first side lip 12b extends from the inner portion 11b of the core 11 toward the hub flange 3b and the outer diameter side. The first side lip 12b contacts the slinger 13. The first side lip 12b is an example of a seal lip included in a seal member.

[0031] The second side lip 12c extends from the core 11 toward the hub flange 3b, which is the outer side, on the inner diameter side of the first side lip 12b. Specifically, the second side lip 12c extends from the inner portion 11b of the core 11 toward the hub flange 3b and the outer diameter side. The second side lip 12c is in sliding contact with the slinger 13. The second side lip 12c is an example of a seal lip included in a seal member.

[0032] The radial lip 12d extends radially inward from the core 11 relative to the second side lip 12c. Specifically, the radial lip 12d extends radially inward from the inner portion 11b of the core 11 toward the inner diameter side and the inner side. The radial lip 12d is in sliding contact with the slinger 13. The radial lip 12d is an example of a seal lip included in a seal member.

[0033] The slinger 13 is made of, for example, a steel plate, and has a cylindrical portion 13a, a disk portion 13b, a connecting portion 13c, and an extending portion 13d.

[0034] The cylindrical portion 13a is formed in a cylindrical shape and is fitted onto the outer peripheral surface 3j of the hub wheel 3, on the inner side of the hub flange 3b. The inner peripheral surface of the cylindrical portion 13a is formed axially parallel to the rotation axis X. The cylindrical portion 13a faces the radial lip 12d in the radial direction, and the cylindrical portion 13a and the radial lip 12d are in contact with each other.

[0035] The outer peripheral surface 3j of the hub wheel 3 has a fitting portion 31 into which the cylindrical portion 13a of the slinger 13 fits. The fitting portion 31 is located on the outer peripheral surface 3j of the hub wheel 3 between the base portion 3d and the inner raceway surface 3c.

[0036] The disc portion 13b is located closer to the hub flange 3b than the cylindrical portion 13a. The disc portion 13b is formed in a disc shape and faces the inner side surface 3g of the base portion 3d of the hub flange 3b. A gap exists between the disc portion 13b and the inner side surface 3g of the hub flange 3b. The disc portion 13b faces the first side lip 12b in the axial direction, and the disc portion 13b and the first side lip 12b are in contact with each other.

[0037] The connecting portion 13c is formed in an arc shape when viewed from the circumferential direction, and connects the cylindrical portion 13a and the disk portion 13b. The connecting portion 13c faces the second side lip 12c in the axial direction, and the connecting portion 13c and the second side lip 12c are in contact with each other.

[0038] The extending portion 13d extends from the outer diameter end of the disc portion 13b toward the inner and outer diameter sides. The outer peripheral surface at the outer end of the outer ring 2 is formed into a tapered surface 2g that decreases in diameter toward the outer side, and the extending portion 13d is formed so as to be parallel to the tapered surface 2g. The extending portion 13d and the tapered surface 2g overlap when viewed radially, and a labyrinth is formed by the extending portion 13d and the tapered surface 2g.

[0039] An elastic member 14 is integrally bonded to the outer side surface at the boundary between the extension 13d and the disk portion 13b. The elastic member 14 is made of, for example, synthetic rubber. The elastic member 14 contacts the inner side surface 3g of the hub flange 3b and seals the gap between the inner side surface 3g of the hub flange 3b and the disk portion 13b of the slinger 13.

[0040] In the outer seal member 10 configured in this manner, when the hub wheel 3 is repeatedly subjected to the vehicle turning load and vibration from the wheel, the received load and vibration are transmitted to the slinger 13, which may cause the slinger 13 to move in the axial direction, such as to the inner side.

[0041] When the slinger 13 moves in the axial direction, the clamping margin of the first side lip 12b and the second side lip 12c that contact the slinger 13 may change, the cylindrical portion 13a of the slinger 13 may interfere with the ball 7 housed between the outer raceway surface 2d of the outer ring 2 and the inner raceway surface 3c of the hub ring 3, or a gap may occur between the slinger 13 and the hub flange 3b, which may allow water to enter the interior of the wheel bearing device 1.

[0042] Therefore, in the wheel bearing device 1, the fitting portion 31 on the outer surface 3j of the hub wheel 3 into which the cylindrical portion 13a of the slinger 13 fits is configured as follows to prevent the slinger 13 from moving in the axial direction.

[0043] [Fitting Portion on Outer Surface of Hub Wheel] As shown in FIG. 3 , the fitting portion 31 of the hub wheel 3 has a small diameter portion 311 , a large diameter portion 312 , and a step portion 313 .

[0044] The small diameter portion 311 is formed on the inner side of the base portion 3d. The radial length from the rotation axis X to the small diameter portion 311 on the outer circumferential surface 3j of the hub wheel 3 is R1.

[0045] The large diameter portion 312 is located on the inner side of the small diameter portion 311. In other words, the large diameter portion 312 is located axially farther from the hub flange 3b than the small diameter portion 311. The large diameter portion 312 is formed to have a larger diameter than the small diameter portion 311, and a step portion 313 is formed between the small diameter portion 311 and the large diameter portion 312.

[0046] The radial length R2 is from the rotational axis X to the large diameter portion 312 on the outer peripheral surface 3j of the hub wheel 3. The step height h of the large diameter portion 312 relative to the small diameter portion 311 is the difference between the radial length R2 from the rotational axis X to the large diameter portion 312 and the radial length R1 from the rotational axis X to the small diameter portion 311 (h = R2 - R1).

[0047] The axial length L1 of small diameter portion 311 and the axial length L2 of large diameter portion 312 are both formed to be greater than the tolerance of the axial length of cylindrical portion 13a of slinger 13. Therefore, even if the axial length of cylindrical portion 13a varies within the tolerance range, when cylindrical portion 13a is fitted into fitting portion 31, slinger 13 can be fitted into both small diameter portion 311 and large diameter portion 312 across step portion 313.

[0048] The step portion 313 is located between the small diameter portion 311 and the large diameter portion 312 in the axial direction, and connects the small diameter portion 311 and the large diameter portion 312. The step portion 313 is formed by an inclined surface whose diameter increases from the small diameter portion 311 toward the large diameter portion 312 in the axial direction.

[0049] The slinger 13 is pressed into the mating portion 31 on the outer peripheral surface 3j of the hub wheel 3 from the inner side, and the cylindrical portion 13a of the slinger 13 has a clamping margin between it and the mating portion 31, but since the large diameter portion 312 is formed with a larger diameter than the small diameter portion 311, the clamping margin between the large diameter portion 312 of the cylindrical portion 13a is greater than the clamping margin between the small diameter portion 311 of the cylindrical portion 13a.

[0050] In the wheel bearing device 1, when the hub wheel 3 is repeatedly subjected to the vehicle turning load and vibration from the wheel, the received load and vibration are transmitted to the slinger 13 of the outer seal member 10, and a force may act on the slinger 13 in a direction that moves it toward the inner side.

[0051] On the other hand, when a force acts on the slinger 13 in a direction that moves it toward the inner side, the greater the clamping margin of the slinger 13 relative to the outer surface 3j of the hub wheel 3, the greater the force required to move the slinger 13 toward the inner side.

[0052] Therefore, by having a small diameter portion 311 and a large diameter portion 312 located on the inner side of the small diameter portion 311, like the mating portion 31 of the hub wheel 3, it is possible to increase the load-bearing capacity against forces in the direction of movement toward the inner side of the slinger 13.

[0053] In particular, even if the axial length of the cylindrical portion 13a of the slinger 13 changes within the tolerance range, the slinger 13 is fitted into both the small diameter portion 311 and the large diameter portion 312, so it is possible to suppress axial movement of the slinger 13 regardless of the quality of the axial length of the cylindrical portion 13a of the slinger 13.

[0054] Furthermore, in the fitting portion 31, the small diameter portion 311 and the large diameter portion 312 are connected by a step portion 313, and the cylindrical portion 13a of the slinger 13 gets caught on the boundary between the step portion 313 and the large diameter portion 312. Therefore, it is possible to effectively increase the load-bearing capacity against forces moving in the direction toward the inner side of the slinger 13 compared to, for example, a case in which the fitting portion 31 is formed in a tapered shape in which the diameter increases smoothly from the outer side toward the inner side.

[0055] Furthermore, if the interference between the cylindrical portion 13a of the slinger 13 and the fitting portion 31 of the hub wheel 3 is too large, plastic deformation may occur in the slinger 13 when the slinger 13 is press-fitted into the fitting portion 31. Therefore, it is preferable that the height h of the step between the large diameter portion 312 and the small diameter portion 311 be equal to or less than half the radial thickness t of the cylindrical portion 13a of the slinger 13 (h≦(t / 2)).

[0056] Setting the step height h to less than half the thickness t prevents the interference between the cylindrical portion 13a of the slinger 13 and the fitting portion 31 of the hub wheel 3 from becoming too large, which would cause plastic deformation of the slinger 13. Furthermore, from the perspective of preventing axial movement of the slinger 13, it is preferable that the step height h between the large diameter portion 312 and the small diameter portion 311 be 10 μm or more.

[0057] In the hub wheel 3, the inclination angle θ of the inclined surface of the step portion 313 located between the large diameter portion 312 and the small diameter portion 311 with respect to the axial direction is set to be equal to or greater than 3° and equal to or less than 45°.

[0058] The larger the inclination angle θ, the greater the load resistance against movement of the slinger 13 toward the inner side, but if the inclination angle θ exceeds 45°, there is a risk that the amount of wear on the slinger 13 due to the step portion 313 when the slinger 13 is press-fitted into the fitting portion 31 may increase, so it is preferable to set the inclination angle θ to 45° or less. Furthermore, from the perspective of suppressing axial movement of the slinger 13, it is preferable to set the inclination angle θ to 3° or more.

[0059] The axial length L3 of the step portion 313 is not particularly limited, but can be set to 1 mm or less. By setting the axial length L3 of the step portion 313 to 1 mm or less, it is possible to set the inclination angle θ of the step portion 313 to a large value.

[0060] [Relationship between the fitting position of the slinger relative to the fitting portion of the hub wheel and the pull-out force of the slinger] As shown in [A] of Figure 4, for example, when the cylindrical portion 13a of the slinger 13 is fitted only into the small diameter portion 311 of the fitting portion 31 and a gap is created between the inner side end, which is the tip of the cylindrical portion 13a, and the step portion 313, the pull-out force, which is the force required to move the slinger 13 toward the inner side, is F1.

[0061] When the slinger 13 moves from the state shown in [A] of Figure 4 to the inner side, and the inner end of the cylindrical portion 13a of the slinger 13 reaches the step portion 313 as shown in [B] of Figure 4, and the cylindrical portion 13a rides up the step portion 313 toward the large diameter portion 312, the pulling force of the slinger 13 becomes pulling force F2, which is greater than pulling force F1 (F2 > F1).

[0062] 4[C], when the cylindrical portion 13a of the slinger 13 rides up onto the large diameter portion 312 and is engaged with both the small diameter portion 311 and the large diameter portion 312, and the slinger 13 continues to move inward, the pull-out force of the slinger 13 increases as the slinger 13 moves inward. The pull-out force of the slinger 13 reaches a maximum pull-out force F3 (F3>F2) just before the outer end of the cylindrical portion 13a of the slinger 13 moving inward reaches the large diameter portion 312.

[0063] As shown in [D] of Figure 4, when the outer end of the cylindrical portion 13a of the slinger 13 rides up onto the large diameter portion 312 and the entire cylindrical portion 13a is fitted into the large diameter portion 312, the pulling force of the slinger 13 becomes slightly smaller than the pulling force F3 and becomes a pulling force F4 (F4 < F3).

[0064] Thus, the pulling force when the cylindrical portion 13a of the slinger 13 is engaged with both the small diameter portion 311 and the large diameter portion 312 is in the range of pulling force F2 to pulling force F3, and is greater than the pulling force F1 when the cylindrical portion 13a of the slinger 13 is engaged only with the small diameter portion 311 and a gap is created between the inner side end of the cylindrical portion 13a and the step portion 313.

[0065] Therefore, it is possible to prevent axial movement of the slinger 13 when the cylindrical portion 13a is fitted into both the small diameter portion 311 and the large diameter portion 312. In particular, the pull-out force of the slinger 13 reaches a maximum pull-out force F3 just before the outer end of the cylindrical portion 13a reaches the large diameter portion 312, so that the state in which the cylindrical portion 13a is fitted into both the small diameter portion 311 and the large diameter portion 312 can be maintained.

[0066] [Second embodiment of fitting portion in hub wheel] The fitting portion 31 of the hub wheel 3 can also be formed as fitting portion 32 shown in Figure 5. The fitting portion 32 is located between the base portion 3d and the inner raceway surface 3c on the outer peripheral surface 3j of the hub wheel 3, and has a small diameter portion 321, a large diameter portion 322, and a stepped portion 323. The small diameter portion 321 and the stepped portion 323 of the fitting portion 32 are formed in the same manner as the small diameter portion 311 and the stepped portion 313 of the fitting portion 31.

[0067] The large diameter portion 322 is located on the inner side of the small diameter portion 321. In other words, the large diameter portion 322 is located axially farther from the hub flange 3b than the small diameter portion 321. The large diameter portion 322 is formed to have a larger diameter than the small diameter portion 321, and a step portion 323 is formed between the large diameter portion 322 and the small diameter portion 321.

[0068] The large diameter portion 322 has a first large diameter portion 322 a, a second large diameter portion 322 b, and a step portion 322 c. The first large diameter portion 322 a is formed continuous with the inner side of the step portion 323 .

[0069] The second large diameter portion 322b is located on the inner side of the first large diameter portion 322a. In other words, the second large diameter portion 322b is located axially farther from the hub flange 3b than the first large diameter portion 322a.

[0070] The first large diameter portion 322a and the second large diameter portion 322b are formed to have a larger diameter than the small diameter portion 321. The second large diameter portion 322b is formed to have a larger diameter than the first large diameter portion 322a, and a step portion 322c is formed between the first large diameter portion 322a and the second large diameter portion 322b.

[0071] The step portion 322c connects the first large diameter portion 322a and the second large diameter portion 322b. The step portion 322c is formed by an inclined surface whose diameter increases in the axial direction from the first large diameter portion 322a to the second large diameter portion 322b. The step portion 322c can be formed in the same manner as the step portion 313.

[0072] The cylindrical portion 13a of the slinger 13 is fitted over the small diameter portion 321, the first large diameter portion 322a, and the second large diameter portion 322b of the fitting portion 32. In the fitting portion 32, the small diameter portion 321, the first large diameter portion 322a, and the second large diameter portion 322b are arranged in this order from the outer side to the inner side.

[0073] The interference of the cylindrical portion 13a relative to the first large diameter portion 322a is greater than the interference of the cylindrical portion 13a relative to the small diameter portion 321, and the interference of the cylindrical portion 13a relative to the second large diameter portion 322b is greater than the interference of the cylindrical portion 13a relative to the first large diameter portion 322a. In other words, the interference of the cylindrical portion 13a relative to the fitting portion 32 increases from the outer side toward the inner side. This makes it possible to increase the load resistance against a force that moves the slinger 13 toward the inner side.

[0074] In this way, the large diameter portion 322 can have multiple portions with different outer diameters, such as the first large diameter portion 322a and the second large diameter portion 322b. In this embodiment, the large diameter portion 322 has two portions with different outer diameters, but it is also possible to have a configuration with three or more portions with different outer diameters. Furthermore, the multiple portions with different outer diameters can be arranged so that the diameters increase from the outer side to the inner side.

[0075] [Third embodiment of fitting portion in hub wheel] The fitting portion 31 of the hub wheel 3 can also be formed like the fitting portion 33 shown in Figure 6. The fitting portion 33 is located between the base portion 3d and the inner raceway surface 3c on the outer peripheral surface 3j of the hub wheel 3, and has a small diameter portion 331, a large diameter portion 332, and a stepped portion 333. The small diameter portion 331 and the stepped portion 333 of the fitting portion 33 are formed in the same manner as the small diameter portion 311 and the stepped portion 313 of the fitting portion 31.

[0076] The large diameter portion 332 is located on the inner side of the small diameter portion 331. In other words, the large diameter portion 332 is located axially farther from the hub flange 3b than the small diameter portion 331. The large diameter portion 332 has a portion formed with a larger diameter than the small diameter portion 331, and a step portion 333 is formed between the large diameter portion 332 and the small diameter portion 331.

[0077] The large diameter portion 332 has a first large diameter portion 332 a, a second large diameter portion 332 b, a recess 332 c, a first step portion 332 d, and a second step portion 332 e. The first large diameter portion 332 a is formed continuously with the inner side of the step portion 333.

[0078] The second large diameter portion 332b is located on the inner side of the first large diameter portion 332a. In other words, the second large diameter portion 332b is located axially farther from the hub flange 3b than the first large diameter portion 332a.

[0079] The first large diameter portion 332a and the second large diameter portion 332b are formed to have a larger diameter than the small diameter portion 331. The first large diameter portion 332a and the second large diameter portion 332b are formed to have the same diameter. However, the first large diameter portion 332a and the second large diameter portion 332b may be formed to have different outer diameters. In this case, the second large diameter portion 332b may be formed to have a larger diameter than the first large diameter portion 332a, and the first large diameter portion 332a may be formed to have a larger diameter than the second large diameter portion 332b.

[0080] A recess 332c is located between the first large diameter portion 332a and the second large diameter portion 332b. The recess 332c is formed to have a smaller diameter than the first large diameter portion 332a and the second large diameter portion 332b. In other words, the first large diameter portion 332a and the second large diameter portion 332b are located apart in the axial direction with the recess 332c sandwiched therebetween.

[0081] A first step 332d is formed between the first large diameter portion 332a and the recess 332c. The first step 332d connects the first large diameter portion 332a and the recess 332c. The first step 332d is formed by an inclined surface whose diameter decreases in the axial direction from the first large diameter portion 332a toward the recess 332c. The first step 332d can be formed in the same manner as the step 313, except for the inclination direction.

[0082] A second step 332e is formed between the recess 332c and the second large diameter portion 332b. The second step 332e connects the recess 332c and the second large diameter portion 332b. The second step 332e is formed by an inclined surface whose diameter increases in the axial direction from the recess 332c toward the second large diameter portion 332b. The second step 332e can be formed in the same manner as the step 313.

[0083] The cylindrical portion 13a of the slinger 13 is fitted over the small diameter portion 331, the first large diameter portion 332a, the recess 332c, and the second large diameter portion 332b of the fitting portion 33. In the fitting portion 33, the small diameter portion 331, the first large diameter portion 332a, the recess 332c, and the second large diameter portion 332b are arranged in this order from the outer side to the inner side.

[0084] The interference of the cylindrical portion 13a with respect to the first large diameter portion 332a and the second large diameter portion 332b is greater than the interference of the cylindrical portion 13a with respect to the small diameter portion 331, and the interference of the cylindrical portion 13a with respect to the recess 332c is smaller than the interference of the cylindrical portion 13a with respect to the first large diameter portion 332a and the second large diameter portion 332b.

[0085] In other words, between the first large diameter portion 332a and the second large diameter portion 332b, where the interference of the cylindrical portion 13a is larger than that of the small diameter portion 331, there is located a recess 332c, where the interference of the cylindrical portion 13a is smaller than that of the first large diameter portion 332a and the second large diameter portion 332b.

[0086] As a result, when the cylindrical portion 13a of the slinger 13 is fitted into the fitting portion 33, a recess 332c where the tightening margin of the cylindrical portion 13a is small exists between the first large diameter portion 332a and the second large diameter portion 332b where the tightening margin of the cylindrical portion 13a is large, so that the tightening margin of the cylindrical portion 13a can be prevented from becoming too large and causing plastic deformation of the cylindrical portion 13a.

[0087] On the other hand, in the cylindrical portion 13a of the slinger 13, the clamping margin of the portion fitted into the first large diameter portion 332a and the second large diameter portion 332b is larger than the clamping margin of the portion fitted into the small diameter portion 331, so it is possible to increase the load-bearing capacity against forces moving in the direction toward the inner side of the slinger 13.

[0088] In this way, the large diameter portion 332 has a configuration in which a small diameter portion is located between large diameter portions, such as a configuration in which a recess 332c is formed between the first large diameter portion 332a and the second large diameter portion 332b. Furthermore, the large diameter portion 332 may have a configuration in which a small diameter portion is formed between large diameter portions, repeated multiple times in the axial direction. Furthermore, the large diameter portion 332 according to the third embodiment and the large diameter portion 322 according to the second embodiment may be arranged side by side in the axial direction.

[0089] [Second Embodiment of Cylindrical Portion of Slinger] The cylindrical portion 13a of the slinger 13 that is fitted into the fitting portion 31 of the hub wheel 3 can also be formed like the cylindrical portion 113a of a slinger 113 shown in FIG.

[0090] The cylindrical portion 113a is formed continuously with the inner side of the connecting portion 113c of the slinger 113. The inner peripheral surface of the cylindrical portion 113a is formed into a tapered surface whose diameter increases from the outer side toward the inner side, and is inclined with respect to the rotation axis X.

[0091] The cylindrical portion 113a of the slinger 113 is fitted over the small diameter portion 311 and the large diameter portion 312, and the interference of the portion of the cylindrical portion 113a that fits into the large diameter portion 312 is greater than the interference of the portion of the cylindrical portion 113a that fits into the small diameter portion 311.

[0092] However, the cylindrical portion 113a expands in diameter toward the inner side, and the inner part of the cylindrical portion 113a that fits into the large diameter portion 312 is formed with a larger diameter than the outer part of the cylindrical portion 113a that fits into the small diameter portion 311, so the tightening margin of the part of the cylindrical portion 113a that fits into the large diameter portion 312 does not become excessively large.

[0093] This makes it possible to increase the load resistance against a force that moves the slinger 13 toward the inner side while suppressing plastic deformation of the slinger 13. Furthermore, because the interference of the portion of the cylindrical portion 113a that fits into the large diameter portion 312 does not become excessively large, the pressing force when the slinger 113 is press-fitted into the fitting portion 31 of the hub wheel 3 can be reduced, improving the workability of the press-fitting operation.

[0094] Note that the wheel bearing device 1 in this embodiment is configured as a wheel bearing device 1 of a third-generation structure in which the inner raceway surface 3c is formed directly on the outer periphery of the hub wheel 3, but is not limited to this, and the wheel bearing device 1 can also have a fourth-generation structure in which, instead of forming an inner raceway surface opposing the outer raceway surface 2c of the outer ring 2 on the inner ring 4, it is formed on a constant velocity universal joint that fits into the through hole 3i of the hub wheel 3, and is configured without an inner ring 4. In this case, the constant velocity universal joint becomes a raceway surface forming member connected to the hub wheel.

[0095] A wheel bearing device of the fourth generation structure that does not include an inner ring 4 can be configured, for example, as a wheel bearing device 1A shown in Fig. 8. The wheel bearing device 1A includes a constant velocity universal joint 50 connected to a hub wheel 3A, and does not include an inner ring 4. The constant velocity universal joint 50 is an example of a raceway surface forming member connected to a hub wheel.

[0096] Constant velocity universal joint 50 includes a mouth portion 52 that supports a shaft to which driving force from a drive source is input, and a stem portion 53 that extends toward the outer side from mouth portion 52. Hub wheel 3A has a through hole 3i that passes through in the axial direction, and through hole 3i and stem portion 53 are spline-fitted.

[0097] An inner raceway surface 58 that faces the inner outer raceway surface 2 c of the outer ring 2 is formed on the outer peripheral surface of the outer end of the mouth portion 52. The inner raceway surface 58 is an example of the other inner raceway surface that faces the outer raceway surface. The inner ball row 5 is rollably sandwiched between the inner outer raceway surface 2 c of the outer ring 2 and the inner raceway surface 58 of the mouth portion 52 of the constant velocity universal joint 50.

[0098] That is, in the wheel bearing device 1A, the constant velocity universal joint 50 having the inner raceway surface 58 opposing the outer raceway surface 2c of the outer ring 2 also serves as the inner ring.

[0099] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, which are merely examples, and it goes without saying that the present invention can be embodied in various other forms without departing from the spirit of the present invention. The scope of the present invention is indicated by the claims, and further includes the equivalent meanings set forth in the claims, and all modifications within the scope of the claims.

[0100] The present invention can be used in a wheel bearing device.

[0101] DESCRIPTION OF SYMBOLS 1 Wheel bearing device 2 Outer ring 2b Outer-side opening 2c (inner-side) outer raceway surface 2d (outer-side) outer raceway surface 3 Hub ring 3b Hub flange 3c Inner raceway surface 3d Base 3j Outer peripheral surface 4 Inner ring 4a Inner raceway surface 5 Inner-side ball row 6 Outer-side ball row 10 Outer-side seal member 11 Core metal 12 Seal member 12b First side lip 12c Second side lip 12d Radial lip 13, 113 Slinger 13a, 113a Cylindrical portion 13b Disc portion 31 Fitting portion 311, 321, 331 Small diameter portion 312, 322, 332 Large diameter portion 313, 323, 333 Step portion 322a, 332a First large diameter portion 322b, 332b Second large diameter portion 332c Recessed portion h Step height t Thickness S Annular space

Claims

1. A wheel bearing assembly comprising: an inner member comprising an outer member having a double-row outer raceway on its inner circumference; a hub wheel having on its outer circumference one inner raceway facing the outer raceway surface and a hub flange for mounting a wheel; and a raceway surface forming member connected to the hub wheel and having on its outer circumference the other inner raceway surface facing the outer raceway surface; double-row rolling elements accommodated so as to be rollable between the raceway surfaces of the outer member and the inner member; and a sealing device closing an opening end on one axial end side of an annular space formed by the outer member and the inner member, wherein the sealing device comprises: a slinger provided at a base of the hub flange and having a cylindrical portion that fits with the outer peripheral surface of the hub wheel and a disc portion that faces the hub flange; and a seal member having a seal lip, wherein the outer peripheral surface of the hub wheel has a fitting portion into which the cylindrical portion of the slinger fits, The fitting portion has a small diameter portion and a large diameter portion that is located axially farther from the hub flange than the small diameter portion and has a larger diameter than the small diameter portion.

2. A wheel bearing device as set forth in claim 1, wherein a radial step height of said large diameter portion relative to said small diameter portion is equal to or less than half the radial thickness of said cylindrical portion of said slinger.

3. A wheel bearing device as described in claim 1 or claim 2, wherein the fitting portion has a step portion connecting the small diameter portion and the large diameter portion, the step portion is formed by an inclined surface that increases in diameter in the axial direction from the small diameter portion to the large diameter portion, and the inclination angle of the inclined surface with respect to the axial direction is equal to or greater than 3° and equal to or less than 45°.

4. A wheel bearing device as described in claim 1 or claim 2, wherein the large diameter portion has a first large diameter portion formed to have a larger diameter than the small diameter portion, and a second large diameter portion formed to have a larger diameter than the first large diameter portion, and the second large diameter portion is located farther from the hub flange than the first large diameter portion.

5. A wheel bearing device as described in claim 1 or claim 2, wherein the large diameter portion has a first large diameter portion and a second large diameter portion formed to have a larger diameter than the small diameter portion, and a recess having a smaller diameter than the first large diameter portion and the second large diameter portion is formed between the first large diameter portion and the second large diameter portion in the axial direction.

6. A wheel bearing device according to claim 1 or 2, wherein the cylindrical portion of the slinger is formed in a tapered shape that increases in diameter as it moves away from the disk portion in the axial direction.

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