Wheel bearing device

Abstract

In a wheel bearing device, the width of the wheel bearing device can be reduced by narrowing the axial outer portion of the rolling elements while ensuring the fitting force of the sealing device. [Solution] A wheel bearing device 1, wherein the sealing device that closes the annular space formed by the outer member and the inner member comprises core metals 30 and 50, the core metals 30 and 50 comprising fitting portions 31 and 51 that are fitted to the outer member, and side plate portions 32 and 52 that extend from the fitting portions 31 and 51 toward the inner diameter, the side plate portions 32 and 52 having outer diameter side ends 33 and 53, inner diameter side ends 34 and 54, and connecting portions 35 and 55 that connect the outer diameter side ends 33 and 53 and the inner diameter side ends 34 and 54, the outer diameter side ends 33 and 53 are located axially inward from the inner diameter side ends 34 and 54, the side plate portions 32 and 52 have opposing surfaces 36 and 56 that face the rolling element, and the opposing surfaces 36 and 56 are composed of curved surfaces whose cross-sectional shape, when viewed from the circumferential direction, is an arc shape that is convex toward the side opposite to the rolling element side.

Description

Technical Field

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

Background Art

[0002] In recent years, in vehicles using wheel bearing devices, fuel regulations have been imposed due to social backgrounds such as energy conservation and decarbonization, and the trend towards electrification has been progressing. In the future, in electric vehicles that use an in-vehicle battery as the main power source and are expected to spread, the vehicle weight is larger and the axle load tends to increase compared to gasoline vehicles.

[0003] Generally, when the axle load increases, the rotational torque of the wheel bearing device increases, and it is necessary to increase the size of the wheel bearing device from the viewpoint of strength. For example, in a wheel bearing device used in an electric vehicle, the axial distance from the outer side surface of the wheel mounting flange of the hub ring to the inner side end of the inner ring is smaller than the outer diameter of the inner side end of the outer ring, and it tends to be narrow and large in diameter. Also, the mounting dimensions of the wheel bearing device often do not change significantly from the conventional ones, and in order to achieve a narrow and large diameter, it is conceivable to cope with it by reducing the dimensions of each part. However, there is a possibility that the rigidity of the wheel bearing device may decrease due to the reduction in width and increase in diameter.

[0004] Patent Document 1 describes a wheel bearing device including an outer member, an inner member, a double row of rolling elements rotatably accommodated between both raceway surfaces of the inner member and the outer member, and a sealing device that closes an annular space formed by the outer member and the inner member, and having a configuration that satisfies the relationship of "pitch circle diameter P.C.D of the rolling element > 6 × diameter of the rolling element". By configuring in this way, the rigidity of the wheel bearing device with a reduced width and increased diameter is improved.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In order to narrow the width of the wheel bearing device, it is conceivable to make the axially outer portion of the rolling elements in the outer member narrower. By making the axially outer portion of the rolling elements in the outer member narrower, the axial space in which the sealing device is arranged becomes narrower. Then, in order to match the narrowed axially outer portion of the rolling elements in the outer member, it is conceivable to make the axial width of the sealing device narrower as well. However, by narrowing the axial width of the sealing device, the force that fits it into the annular space formed by the outer member and the inner member will weaken, and there is a risk that the sealing device will fall out of the annular space.

[0007] Therefore, the present invention aims to provide a wheel bearing device that can achieve a narrower width by configuring the axially outer portion of the rolling elements in the outer member to be narrower while ensuring the fitting force of the sealing device. [Means for solving the problem]

[0008] That is, an outer member having double rows of outer raceway surfaces on its inner circumference, An inner member having a double row of inner raceway surfaces on its outer circumference that are opposite to the double row of outer raceway surfaces, A double row of rolling elements is housed so as to be able to roll between the raceway surfaces of the inner member and the outer member, A pair of retainers that each hold the double row of rolling elements, A sealing device that closes the annular space formed by the outer member and the inner member, In a wheel bearing device equipped with, The sealing device comprises a core metal fitted into the outer member and a sealing member joined to the core metal. The core metal comprises a fitting portion that fits into the outer member and a side plate portion that extends inward from the fitting portion. The side plate portion has an outer diameter end, an inner diameter end, and a connecting portion that connects the outer diameter end and the inner diameter end, wherein the outer diameter end is located axially inward from the inner diameter end. The side plate portion has a surface facing the rolling element, The opposing surface is a curved surface whose cross-sectional shape, when viewed from the circumferential direction, is an arc shape that is convex toward the side opposite to the rolling element. [Effects of the Invention]

[0009] The present invention provides the following effects. Specifically, according to the present invention, it is possible to narrow the width of a wheel bearing device by configuring the axial outer portion of the rolling element to be narrower while ensuring the fitting force of the sealing device. [Brief explanation of the drawing]

[0010] [Figure 1] A cross-sectional view showing a wheel bearing device according to one embodiment of the present invention. [Figure 2] This is an enlarged cross-sectional view showing the inner and outer sealing members of a wheel bearing device. [Figure 3] This is an enlarged cross-sectional view showing the inner sealing member of a wheel bearing device. [Figure 4] This is an enlarged cross-sectional view showing the outer sealing member of a wheel bearing device. [Figure 5] This is an enlarged cross-sectional view showing the inner and outer sealing members of a wheel bearing device. [Figure 6] This is an enlarged cross-sectional view showing the inner sealing member of a wheel bearing device. [Figure 7] This is an enlarged cross-sectional view showing the outer sealing member of a wheel bearing device. [Figure 8] This is an enlarged cross-sectional view showing the inner ball row, outer ball row, and cage of a wheel bearing device. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

[0012] [Overall Configuration of Wheel Bearing Device] First, the wheel bearing device 1 shown in FIGS. 1 to 8 will be described. The wheel bearing device 1 shown in FIG. 1 is an embodiment of the wheel bearing device according to the present invention, and rotatably supports a wheel in a suspension device of a vehicle such as an automobile.

[0013] As shown in FIGS. 1 to 2, the wheel bearing device 1 has a configuration called the third generation, and includes an outer ring 2 constituting an outer member, a hub ring 3 and an inner ring 4 constituting an inner member, two rows of inner side ball rows 5 and outer side ball rows 6 that are rolling element rows, an inner side seal member 9, and an outer side seal member 10.

[0014] Here, the inner side refers to the vehicle body side of the wheel bearing device 1 when attached to the vehicle body, and the outer side refers to the wheel side of the wheel bearing device 1 when attached to the vehicle body. Further, the axial direction refers to the direction along the rotation axis X of the wheel bearing device 1, one side in the axial direction is the outer side, and the other side in the axial direction is the inner side. Also, the inner side in the axial direction is the axial center position P3 side between the center P1 of the inner side ball row 5 and the center P2 of the outer side ball row, and the outer side in the axial direction is the axial end face 2g side of the outer ring 2 which is an outer member. Further, the direction orthogonal to the rotation axis of the wheel bearing device 1 is referred to as the radial direction. The direction along an arc centered on the rotation axis of the wheel bearing device 1 is referred to as the circumferential direction. Also, hereinafter, the cross section will be described as indicating a cross section passing through the rotation axis of the wheel bearing device 1 and parallel to the rotation axis of the wheel bearing device 1.

[0015] On the inner peripheral surface of the outer ring 2, an outer raceway groove 2c on the inner side and an outer raceway groove 2d on the outer side are formed. On the outer peripheral surface of the outer ring 2, a vehicle body mounting flange 2e for attaching the outer ring 2 to a vehicle body side member is integrally formed. The vehicle body mounting flange 2e is provided with bolt holes 2f into which fastening members (here, bolts) for fastening the vehicle body side member and the outer ring 2 are inserted.

[0016] At the inner side end of the outer peripheral surface of the hub ring 3, a small-diameter step portion 3a that is reduced in diameter compared to the outer side end and has a small diameter extending in the axial direction is formed on the outer periphery. At the outer side end of the hub ring 3, a wheel mounting flange 3b for mounting the wheel is integrally formed. A plurality of bolt holes 3d are formed in the wheel mounting flange 3b. Hub bolts are press-fitted into the bolt holes 3d from the wheel side to fasten the hub ring 3 and the wheel or brake components. Also, as a structure for fastening the hub ring 3 and the wheel or brake components, wheel bolts may be screwed on from the wheel side.

[0017] On the outer peripheral surface of the hub ring 3, an inner side raceway groove 3c on the outer side is provided so as to face the outer side raceway groove 2d on the outer side of the outer ring 2. That is, on the outer side of the inner member, the inner side raceway groove 3c is formed by the hub ring 3. A seal land portion 3e is formed on the outer side of the inner side raceway groove 3c. An outer side opening 2b, which is an annular space, is formed between the outer ring 2 and the hub ring 3. The outer side seal member 10 is fitted into the outer side opening 2b to prevent the intrusion of foreign matters such as muddy water from the outer side opening 2b. The outer side seal member 10 is an example of a sealing device.

[0018] The inner ring 4 is provided on the small-diameter step portion 3a of the hub ring 3. The inner ring 4 is press-fitted into the small-diameter step portion 3a via a predetermined tightening washer. The inner ring 4 applies preload to the inner side ball row 5 and the outer side ball row 6, which are rolling element rows. On the outer peripheral surface of the inner ring 4, an inner side raceway groove 4a on the inner side is provided so as to face the outer side raceway groove 2c on the inner side of the outer ring 2. That is, on the inner side of the inner member, the inner side raceway groove 4a is formed by the inner ring 4. An inner side opening 2a, which is an annular space, is formed between the outer ring 2 and the inner ring 4. The inner side seal member 9 is fitted into the inner side opening 2a to prevent the intrusion of foreign matters such as muddy water from the inner side opening 2a. The inner side seal member 9 is an example of a sealing device.

[0019] The inner ball row 5 and the outer ball row 6, which are rolling elements, are composed of multiple balls 7, which are rolling elements, held by a cage 8. The inner ball row 5 is rotatably sandwiched between the inner raceway groove 4a of the inner ring 4 and the inner outer raceway groove 2c of the outer ring 2. The outer ball row 6 is rotatably sandwiched between the inner raceway groove 3c of the hub ring 3 and the outer outer raceway groove 2d of the outer ring 2. In other words, the inner ball row 5 and the outer ball row 6 are rotatably housed between the raceway grooves of the outer and inner members. In the wheel bearing device 1, a double-row angular contact ball bearing is composed of the outer ring 2, the hub ring 3 and the inner ring 4, the inner ball row 5 and the outer ball row 6.

[0020] [Specific configuration of the inner sealing member] As shown in Figure 2 or Figure 3, the inner sealing member 9 comprises a slinger 20, a core metal 30, and a sealing member 40.

[0021] The slinger 20 is configured in a substantially annular shape and is fitted onto the inner ring 4. The slinger 20 is formed from a metal member, for example, made of steel, and has a substantially L-shaped cross-section. The slinger 20 faces the core metal 30 in the axial direction. The slinger 20 has an outer mating portion 21, an annular portion 22, and a magnetic encoder 23.

[0022] The outer fitting portion 21 of the slinger 20 is cylindrical and fits onto the outer circumference of the inner end of the inner ring 4. The outer fitting portion 21 is configured parallel to the axial direction. The annular portion 22 is annular and is located on the outer diameter side of the outer fitting portion 21. The annular portion 22 extends outward from the outer fitting portion 21. The annular portion 22 is configured parallel to the radial direction. The inner diameter side end of the annular portion 22 is connected to the inner side end of the outer fitting portion 21. The magnetic encoder 23 is made of synthetic rubber or the like with magnetic poles (N pole and S pole) arranged in an annular shape. The magnetic encoder 23 is provided so as to cover the inner side surface of the annular portion 22. The magnetic encoder 23 is configured as part of the slinger 20. Note that the slinger 20 may be configured without the magnetic encoder 23.

[0023] The core metal 30 is configured in a substantially annular shape and is fitted to the inner circumference of the inner end of the outer ring 2. The core metal 30 is positioned such that a predetermined gap is formed between it and the slinger 20, and the core metal 30 and the slinger 20 are configured to be non-contact. The core metal 30 is made of a metal member, for example, made of steel. The core metal 30 has a fitting portion 31 and a side plate portion 32.

[0024] The fitting portion 31 of the core metal 30 is cylindrical in shape and fits onto the inner circumference of the inner end of the outer ring 2. The fitting portion 31 is configured parallel to the axial direction. The side plate portion 32 is located on the inner diameter side of the fitting portion 31 and extends inward from the fitting portion 31. The outer diameter side end of the side plate portion 32 is connected to the outer end of the fitting portion 31. The side plate portion 32 faces the balls 7 of the inner ball row 5. The side plate portion 32 has a facing surface 36 that faces the balls 7 of the inner ball row 5.

[0025] The sealing member 40 is made of, for example, synthetic rubber and is configured to be elastically deformable. The sealing member 40 is joined to the core metal 30 by vulcanization bonding or the like. The sealing member 40 has a base portion 41, two axial lips 42, and a radial lip 43.

[0026] The base 41 of the sealing member 40 is provided so as to cover the inner end face of the fitting portion 31 of the core metal 30, the inner diameter side surface of the fitting portion 31, the inner side surface of the side plate portion 32, the inner diameter end face of the side plate portion 32, and a part of the outer side surface of the side plate portion 32. The base 41 of the sealing member 40 is formed as part of the core metal 30.

[0027] The axial lip 42 of the sealing member 40 is configured to be elastically deformable. The axial lip 42 prevents foreign matter such as muddy water from entering between the slinger 20 and the core metal 30. The axial lip 42 extends from the side plate portion 32 of the core metal 30 toward the annular portion 22 of the slinger 20. The axial lip 42 extends toward the outer diameter side and the inner side, and contacts the outer surface of the annular portion 22 of the slinger 20. The two axial lips 42 are arranged side by side in the radial direction.

[0028] The radial lip 43 of the sealing member 40 is configured to be elastically deformable. The radial lip 43 prevents foreign matter such as muddy water from entering between the slinger 20 and the core metal 30, and also prevents grease from leaking out from the inner side ball row 5. The radial lip 43 extends from the side plate portion 32 of the core metal 30 toward the outer fitting portion 21 of the slinger 20. The radial lip 43 extends toward the inner diameter side and the outer side, and contacts the outer diameter side surface of the outer fitting portion 21 of the slinger 20.

[0029] [Specific configuration of the core metal of the inner sealing member] The side plate portion 32 of the core metal 30 has an outer diameter side end 33, an inner diameter side end 34, and a connecting portion 35.

[0030] The outer diameter end 33 of the side plate portion 32 of the core metal 30 is annular in shape and is located on the inner diameter side of the fitting portion 31. The outer diameter end 33 extends from the fitting portion 31 toward the inner diameter side. The outer diameter end of the outer diameter end 33 is connected to the outer end of the fitting portion 31. The inner diameter end 34 is annular in shape and is located on the inner diameter side of both the fitting portion 31 and the outer diameter end 33.

[0031] The connecting portion 35 of the side plate portion 32 of the core metal 30 connects the outer diameter end 33 and the inner diameter end 34. The connecting portion 35 is configured to be inclined with respect to the axial and radial directions. The connecting portion 35 is located on the inner diameter side of the outer diameter end 33 and extends from the outer diameter end 33 toward the inner diameter and inner side. The connecting portion 35 is located on the outer diameter side of the inner diameter end 34 and extends from the inner diameter end 34 toward the outer diameter and outer side. The outer diameter end of the connecting portion 35 is connected to the inner diameter end of the outer diameter end 33, and the inner diameter end of the connecting portion 35 is connected to the outer diameter end of the inner diameter end 34. The opposing surfaces 36 of the side plate portion 32 of the core metal 30 are curved surfaces whose cross-sectional shape, when viewed from the circumferential direction, is an arc shape that is convex toward the opposite side (outer diameter and inner side) from the ball 7 side of the inner ball row 5. Here, "cross-sectional shape" refers to the cross-sectional shape in a cross section that passes through and is parallel to the axis of rotation X. With this configuration, the space formed by the opposing surface 36 of the side plate portion 32 of the core metal 30 and the ball 7 can be made relatively small compared to a configuration in which the opposing surface 36 of the side plate portion 32 of the core metal 30 is bent. Therefore, the amount of grease sealed in the space formed by the opposing surface 36 of the side plate portion 32 of the core metal 30 and the ball 7 can be made relatively small. Furthermore, with this configuration, the size of the gap S1 between the opposing surface 36 of the side plate portion 32 of the core metal 30 and the ball 7 in the radial direction of the ball 7 is made generally uniform throughout. Therefore, compared to a configuration in which the opposing surface 36 of the side plate portion 32 of the core metal 30 is bent, the grease scraped out by the rotation of the ball 7 can be more easily returned to the space formed by the opposing surface 36 of the side plate portion 32 of the core metal 30 and the ball 7.

[0032] The outer diameter end 33 of the side plate portion 32 of the core metal 30 is located on the outer side (axially inward) than the inner diameter end 34. This configuration allows for a narrower axial width of the fitting portion 31 of the core metal 30 while maintaining the fitting force with respect to the outer ring 2, and also allows for a narrower inner portion (axially outward portion) of the inner ball row 5 in the wheel bearing device 1 (outer ring 2). Therefore, it is possible to achieve a narrower width for the wheel bearing device 1 while ensuring the fitting force of the inner seal member 9 with respect to the outer ring 2.

[0033] The outer diameter end 33 of the side plate portion 32 of the core metal 30 is located on the outer side (axially inward) than the inner end (axially outward end) of the balls 7 (opposing rolling elements) of the inner ball row 5. By configuring it in this way, the axial width of the fitting portion 31 of the core metal 30 can be made narrower to the extent that the fitting force with respect to the outer ring 2 is maintained, while the inner portion (axially outward portion) of the inner ball row 5 in the wheel bearing device 1 (outer ring 2) can be made narrower. Therefore, the width of the wheel bearing device 1 can be reduced while ensuring the fitting force of the inner seal member 9 with respect to the outer ring 2.

[0034] Furthermore, it is preferable that the opposing surface 36 of the side plate portion 32 of the core metal 30 is a curved surface whose cross-sectional shape, when viewed from the circumferential direction, is an arc shape centered on the rolling element center P1, which is the center of the balls 7 of the inner ball row 5. In this case, the length L1 from the rolling element center P1, which is the center of the balls 7 of the inner ball row 5, to the opposing surface 36 of the side plate portion 32 of the core metal 30, the radius R1 of the balls 7 of the inner ball row 5, and the gap S1 between the opposing surface 36 of the side plate portion 32 of the core metal 30 and the ball 7 in the radial direction of the ball 7 are expressed as L1 = R1 + S1, and the gap S1 is said to include a range of S1 ± 0.5 mm. In other words, the gap S1 can include an error in the range of ± 0.5 mm. By configuring it in this way, the space formed by the opposing surface 36 and the ball 7 can be made even smaller compared to a configuration in which the opposing surface 36 of the side plate portion 32 of the core metal 30 is bent. Therefore, the amount of grease sealed in the space formed by the opposing surface 36 of the side plate portion 32 of the core metal 30 and the ball 7 can be further reduced. Furthermore, with this configuration, the size of the gap S1 between the opposing surface 36 of the side plate portion 32 of the core metal 30 and the ball 7 in the radial direction of the ball 7 is made uniform throughout. Therefore, compared to a configuration in which the opposing surface 36 of the side plate portion 32 of the core metal 30 is bent, the grease scraped out by the rotation of the ball 7 can be returned more easily to the space formed by the opposing surface 36 of the side plate portion 32 of the core metal 30 and the ball 7.

[0035] As shown in Figure 5 or Figure 6, the connection portion 35 of the side plate portion 32 of the core metal 30 can also be configured to be inclined linearly with respect to the axial and radial directions. By configuring it in this way, the axial width of the fitting portion 31 of the core metal 30 can be made narrower to the extent that the fitting force with respect to the outer ring 2 is maintained, while the inner portion (axially outer portion) of the inner ball row 5 in the wheel bearing device 1 (outer ring 2) can be made narrower. Therefore, it is possible to narrow the width of the wheel bearing device 1 while ensuring the fitting force with respect to the outer ring 2 of the inner sealing member 9.

[0036] [Specific configuration of the outer sealing member] As shown in Figure 2 or Figure 4, the outer sealing member 10 comprises a core metal 50 and a sealing member 60.

[0037] The core metal 50 is configured in a substantially annular shape and is fitted onto the inner circumference of the outer end of the outer ring 2. The core metal 50 is made of a metal member, for example, steel. The core metal 50 has a fitting portion 51 and a side plate portion 52.

[0038] The fitting portion 51 of the core metal 50 is cylindrical in shape and fits onto the inner circumference of the outer end of the outer ring 2. The fitting portion 51 is configured parallel to the axial direction. The side plate portion 52 is located on the inner diameter side of the fitting portion 51 and extends inward from the fitting portion 51. The outer diameter side end of the side plate portion 52 is connected to the inner side end of the fitting portion 51. The side plate portion 52 faces the balls 7 of the outer ball row 6. The side plate portion 52 has a facing surface 56 that faces the balls 7 of the outer ball row 6.

[0039] The sealing member 60 is made of, for example, synthetic rubber and is configured to be elastically deformable. The sealing member 60 is joined to the core metal 50 by vulcanization bonding or the like. The sealing member 60 has a base portion 61, two axial lips 62, and a radial lip 63.

[0040] The base 61 of the sealing member 60 is provided so as to cover the outer end face of the fitting portion 51 of the core metal 50, the inner diameter side surface of the fitting portion 51, the outer side surface of the side plate portion 52, the inner diameter end face of the side plate portion 52, and a part of the inner side surface of the side plate portion 52. The base 61 of the sealing member 60 is formed as part of the core metal 50.

[0041] The axial lip 62 of the sealing member 60 is configured to be elastically deformable. The axial lip 62 prevents foreign matter such as mud and water from entering between the hub wheel 3 and the core metal 50. The axial lip 62 extends from the side plate portion 52 of the core metal 50 toward the seal land portion 3e of the hub wheel 3. The axial lip 62 extends toward the outer diameter and outer side and contacts the seal land portion 3e of the hub wheel 3. Two axial lips 62 are arranged side by side in the radial direction.

[0042] The radial lip 63 of the sealing member 60 is configured to be elastically deformable. The radial lip 63 prevents foreign matter such as mud and water from entering between the hub wheel 3 and the core metal 50, and also prevents grease from leaking out from the outer ball row 6 side. The radial lip 63 extends from the side plate portion 52 of the core metal 50 toward the seal land portion 3e of the hub wheel 3. The radial lip 63 extends toward the inner diameter side and the inner side, and contacts the seal land portion 3e of the hub wheel 3.

[0043] [Specific configuration of the core metal of the outer sealing member] The side plate portion 52 of the core metal 50 has an outer diameter side end 53, an inner diameter side end 54, and a connecting portion 55.

[0044] The outer diameter end 53 of the side plate portion 52 of the core metal 50 is annular in shape and is located on the inner diameter side of the fitting portion 51. The outer diameter end 53 extends from the fitting portion 51 toward the inner diameter side. The outer diameter end of the outer diameter end 53 is connected to the inner side end of the fitting portion 51. The inner diameter end 54 of the side plate portion 52 is annular in shape and is located on the inner diameter side of both the fitting portion 51 and the outer diameter end 53.

[0045] The connecting portion 55 of the side plate portion 52 of the core metal 50 connects the outer diameter end 53 and the inner diameter end 54. The connecting portion 55 is configured to be inclined with respect to the axial and radial directions. The connecting portion 55 is located on the inner diameter side of the outer diameter end 53 and extends from the outer diameter end 53 toward the inner diameter and outer side. The connecting portion 55 is located on the outer diameter side of the inner diameter end 54 and extends from the inner diameter end 54 toward the outer diameter and inner side. The outer diameter end of the connecting portion 55 is connected to the inner diameter end of the outer diameter end 53, and the inner diameter end of the connecting portion 55 is connected to the outer diameter end of the inner diameter end 54. The opposing surfaces 56 of the side plate portion 52 are curved surfaces whose cross-sectional shape, when viewed from the circumferential direction, is an arc shape that is convex toward the opposite side (outer diameter and outer side) from the ball 7 side of the outer ball row 6. Here, "cross-sectional shape" refers to the cross-sectional shape in a cross section that passes through the rotation axis X and is parallel to the rotation axis X. This configuration allows for a narrower axial width of the fitting portion 31 of the core metal 30 while maintaining the fitting force with respect to the outer ring 2, and also allows for a narrower inner portion (axially outer portion) of the inner ball row 5 in the wheel bearing device 1 (outer ring 2). Therefore, it is possible to achieve a narrower width for the wheel bearing device 1 while ensuring the fitting force of the inner sealing member 9 with respect to the outer ring 2. Furthermore, this configuration allows for a relatively smaller space between the opposing surface 56 of the side plate portion 52 of the core metal 50 and the ball 7 compared to a configuration where the opposing surface 56 of the side plate portion 52 of the core metal 50 is bent. Therefore, the amount of grease sealed in the space between the opposing surface 56 of the side plate portion 52 of the core metal 50 and the ball 7 can be reduced. Additionally, this configuration ensures that the size of the gap S2 between the opposing surface 56 of the side plate portion 52 of the core metal 50 and the ball 7 in the radial direction of the ball 7 is generally uniform throughout. Therefore, compared to a configuration in which the opposing surface 56 of the side plate portion 52 of the core metal 50 is bent, the grease scraped out by the rotation of the ball 7 can more easily return to the space formed by the opposing surface 56 of the side plate portion 52 of the core metal 50 and the ball 7.

[0046] The outer diameter end 53 of the side plate portion 52 of the core metal 50 is located on the inner side (axially inward) than the inner diameter end 54. This configuration allows for a narrower axial width of the fitting portion 51 of the core metal 50 while maintaining the fitting force with respect to the outer ring 2, and also allows for a narrower outer portion (axially outward portion) of the outer ball row 6 in the wheel bearing device 1 (outer ring 2). Therefore, it is possible to achieve a narrower width for the wheel bearing device 1 while ensuring the fitting force of the outer sealing member 10 with respect to the outer ring 2.

[0047] The outer diameter end 53 of the side plate portion 52 of the core metal 50 is located on the inner side (axially inward) than the outer end (axially outward end) of the balls 7 (opposing rolling elements) of the outer ball row 6. By configuring it in this way, the axial width of the fitting portion 51 of the core metal 50 can be made narrower to the extent that the fitting force with respect to the outer ring 2 is maintained, while the outer portion (axially outward portion) of the outer ball row 6 in the wheel bearing device 1 (outer ring 2) can be made narrower. Therefore, the width of the wheel bearing device 1 can be reduced while ensuring the fitting force with respect to the outer ring 2 of the outer sealing member 10.

[0048] Furthermore, it is preferable that the opposing surface 56 of the side plate portion 52 of the core metal 50 is a curved surface whose cross-sectional shape, when viewed from the circumferential direction, is an arc shape centered on the rolling element center P2, which is the center of the balls 7 of the outer ball row 6. In this case, the length L2 from the rolling element center P2, which is the center of the balls 7 of the outer ball row 6, to the opposing surface 56 of the side plate portion 52 of the core metal 50, the radius R2 of the balls 7 of the outer ball row 6, and the gap S2 between the opposing surface 56 of the side plate portion 52 of the core metal 50 and the ball 7 in the radial direction of the ball 7 are expressed as L2 = R2 + S2, and the gap S2 is said to include a range of S2 ± 0.5 mm. In other words, the gap S2 can include an error in the range of ± 0.5 mm. By configuring it in this way, the space formed by the opposing surface 56 and the ball 7 can be made even smaller compared to a configuration in which the opposing surface 56 of the side plate portion 52 of the core metal 50 is bent. Therefore, the amount of grease sealed in the space formed by the opposing surface 56 of the side plate portion 52 of the core metal 50 and the ball 7 can be further reduced. Furthermore, with this configuration, the size of the gap S2 between the opposing surface 56 of the side plate portion 52 of the core metal 50 and the ball 7 in the radial direction of the ball 7 is made uniform throughout. Therefore, compared to a configuration in which the opposing surface 56 of the side plate portion 52 of the core metal 50 is bent, the grease scraped out by the rotation of the ball 7 can be returned more easily to the space formed by the opposing surface 56 of the side plate portion 52 of the core metal 50 and the ball 7.

[0049] As shown in Figure 5 or Figure 7, the connection portion 55 of the side plate portion 52 of the core metal 50 can also be configured to be inclined linearly with respect to the axial and radial directions. By configuring it in this way, the axial width of the fitting portion 31 of the core metal 30 can be made narrower to the extent that the fitting force with respect to the outer ring 2 is maintained, while the inner portion (axially outer portion) of the inner ball row 5 in the wheel bearing device 1 (outer ring 2) can be made narrower. Therefore, it is possible to narrow the width of the wheel bearing device 1 while ensuring the fitting force of the inner seal member 9 with respect to the outer ring 2.

[0050] [Specific configuration of the retainer] As shown in Figure 8, each retainer 8 of the inner ball row 5 and the outer ball row 6 has an annular portion 81, a plurality of columnar portions 82, and a pocket 83. The annular portion 81 is formed in an annular shape. The plurality of columnar portions 82 extend axially from multiple points in the circumferential direction of the annular portion 81 toward the outer diameter and are arranged at regular intervals. The pocket 83 is formed by adjacent columnar portions 82 and the annular portion 81 and holds the ball 7. The inner surface of the pocket 83 is configured to be spherical. The annular portion 81 of the retainer 8 in the inner ball row 5 and the annular portion 81 of the retainer 8 in the outer ball row 6 are arranged in a position facing each other.

[0051] The annular portion 81 of the retainer 8 in the inner ball row 5 is located on the outer side (axially inward) of the balls 7 of the inner ball row 5. The annular portion 81 of the retainer 8 in the inner ball row 5 has an inner outer circumference portion 84 located on the outer diameter side and an inner circumference portion 85 located on the inner diameter side of the inner outer circumference portion 84. The inner outer circumference portion 84 and the inner circumference portion 85 are configured in a stepped manner in the axial direction. The inner outer circumference portion 84 protrudes outward (axially inward) than the inner circumference portion 85.

[0052] The annular portion 81 of the retainer 8 in the outer ball row 6 is located on the inner side (axially inward) than the balls 7 of the outer ball row 5. The annular portion 81 of the retainer 8 in the outer ball row 6 has an outer peripheral portion 86 located on the outer diameter side and an outer inner peripheral portion 87 located on the inner diameter side of the outer peripheral portion 86. The outer peripheral portion 86 and the outer inner peripheral portion 87 are configured in a stepped manner in the axial direction. The outer inner peripheral portion 87 protrudes on the inner side (axially inward) than the outer peripheral portion 86.

[0053] The inner outer circumference 84 of the retainer 8 in the inner ball row 5 and the outer outer circumference 86 of the retainer 8 in the outer ball row 6 face each other with a predetermined gap in the axial direction. The inner inner circumference 85 of the retainer 8 in the inner ball row 5 and the outer inner circumference 87 of the retainer 8 in the outer ball row 6 face each other with a predetermined gap in the axial direction. The inner outer circumference 84 of the retainer 8 in the inner ball row 5 and the outer inner circumference 87 of the retainer 8 in the outer ball row 6 face each other with a predetermined gap in the radial direction and overlap when viewed from the radial direction. The inner inner circumference 85 of the retainer 8 in the inner ball row 5 and the outer outer circumference 86 of the retainer 8 in the outer ball row 6 do not overlap when viewed from the radial direction.

[0054] As described above, the inner outer circumference 84 of the cage 8 in the inner ball row 5 protrudes outward from the inner circumference 85, and the outer inner circumference 87 of the cage 8 in the outer ball row 6 protrudes inward from the outer circumference 86, and the inner outer circumference 84 and the outer inner circumference 87 overlap when viewed radially. In this way, a portion of the cage 8 of the inner ball row 5 and the outer ball row 6 overlap when viewed radially. Therefore, the axial distance between the inner ball row 5 and the outer ball row 6 can be made relatively short. Thus, the width of the wheel bearing device 1 can be reduced. Alternatively, the inner inner circumference 85 of the cage 8 in the inner ball row 5 can protrude outward from the inner circumference 84, and the outer outer circumference 86 of the cage 8 in the outer ball row 6 can protrude inward from the outer circumference 87, so that the inner inner circumference 85 and the outer outer circumference 86 overlap when viewed radially.

[0055] Although a wheel bearing device referred to as the third generation has been given as an example, the wheel bearing device according to the present invention is not limited to such a structure. For example, it may be a first-generation or second-generation structure in which a pair of inner rings are press-fitted into the small-diameter stepped portion of the hub ring, or a fourth-generation structure in which inner raceway grooves are formed on the outer circumferential surfaces of the hub ring and the constant velocity universal joint, respectively, and these are used as inner members. Furthermore, although a double-row angular contact ball bearing with a row of balls as the rolling elements has been given as an example, it is not limited to this, and a double-row tapered roller bearing with tapered rollers as the rolling elements is also acceptable.

[0056] Although embodiments of the present invention have been described above, the present invention is not limited in any way to these embodiments, but is merely illustrative. It can be implemented in various other forms without departing from the spirit of the invention, and the scope of the present invention is indicated by the claims, and further includes all modifications within the meaning and scope of equivalents as described in the claims. [Explanation of symbols]

[0057] 1. Wheel bearing device 2 Outer ring 2a Inner side opening 2b Outer side opening 2c Outer raceway groove 2d outer raceway groove 3 Hub wheels 3a Small diameter stepped section 3b Wheel mounting flange 3c Inner raceway groove 3e Seal Land Department 4. Inner Ring 4a Inner raceway groove on the inner side 5. Inner ball row 6 Outer ball rows 7 Ball 8 Cage 9. Inner side sealing member 10 Outer side sealing member 20 Slinger 21 External fitting part 22 Annular section 30 Mandrel 31 Fitting part 32 Side plate part 33 Outer diameter end 34 Inner diameter end 35 Connection part 36 Opposing surfaces 40 sealing member 41 Base 42 Axial Lip 43 Radial Lip 50 Mandrel 51 Fitting part 52 Side plate part 53 Outer diameter end 54 Inner diameter side end 55 Connection part 56 Opposing surfaces 60 sealing member 61 Base 62 Axial Lip 63 Radial Lip 81 Annular section 82 Column section 83 pockets 84 Inner outer circumference 85 Inner side inner circumference 86 Outer circumference 87 Outer side inner circumference

Claims

1. An outer member having double rows of outer raceway surfaces on its inner circumference, An inner member having a double row of inner raceway surfaces on its outer circumference that are opposite to the double row of outer raceway surfaces, A double row of rolling elements is housed so as to be able to roll between the raceway surfaces of the inner member and the outer member, A pair of retainers that each hold the double row of rolling elements, A sealing device that closes the annular space formed by the outer member and the inner member, In a wheel bearing device equipped with, The sealing device comprises a core metal fitted into the outer member and a sealing member joined to the core metal. The core metal comprises a fitting portion that fits into the outer member and a side plate portion that extends inward from the fitting portion. The side plate portion has an outer diameter end, an inner diameter end, and a connecting portion that connects the outer diameter end and the inner diameter end, wherein the outer diameter end is located axially inward from the inner diameter end. The side plate portion has a surface facing the rolling element, The wheel bearing device is configured such that the opposing surface is a curved surface whose cross-sectional shape, when viewed from the circumferential direction, is an arc shape that is convex toward the side opposite to the rolling element side.

2. The wheel bearing device according to claim 1, wherein the outer diameter end of the side plate portion is located axially inward from the axially outer end of the opposing rolling element.

3. The wheel bearing device according to claim 1 or claim 2, wherein the opposing surface is a curved surface whose cross-sectional shape, when viewed from the circumferential direction, is an arc shape centered on the center of the rolling element.

4. The wheel bearing device according to claim 1, wherein the sealing device closes the open end on one axial side of the annular space formed by the outer member and the inner member.

5. The wheel bearing device according to claim 4, wherein the sealing device consists of a pair that closes the axial open end and the axial open end of the annular space formed by the outer member and the inner member, respectively.

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