Wheel bearing assembly

Abstract

The wheel bearing assembly (10) comprises: an inner axle (12) having a wheel mounting flange (18b) on one axial side and a double row of inner raceway surfaces (20) on the other axial side; an outer ring (11) having a double row of outer raceway surfaces (17) opposite to the double row of inner raceway surfaces (20); a plurality of first balls (13a) disposed between the first inner raceway surface (20a) on one axial side of the double row of inner raceway surfaces (20) and the first outer raceway surface (17a) on one axial side of the double row of outer raceway surfaces (17); and a plurality of second balls (13b) disposed between the second inner raceway surface (20b) on the other axial side of the double row of inner raceway surfaces (20) and the second outer raceway surface (17b) on the other axial side of the double row of outer raceway surfaces (17). The plurality of first balls (13a) and the plurality of second balls (13b) have the same diameter. The contact angle of the plurality of first balls (13a) is smaller than the contact angle of the plurality of second balls (13b).

Description

Technical Field

[0001] This invention relates to a bearing assembly for wheels. Background Technology

[0002] To allow the wheels to rotate freely and be supported on the vehicle body, a wheel bearing assembly called a hub unit is used. This wheel bearing assembly sometimes employs double-row angular contact ball bearings.

[0003] The aforementioned wheel bearing assembly includes: an inner square member having a wheel mounting flange on one axial side, an outer square member, and a plurality of balls arranged in a double row and disposed between the two members. The plurality of balls includes a plurality of first balls arranged in a row on one axial side of the double row and a plurality of second balls arranged in a row on the other axial side (for example, see Patent Document 1).

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-31136 Summary of the Invention

[0007] Summary of the invention

[0008] The problem that the invention aims to solve

[0009] However, when a wheel veers over a curb located at the side of the road or when the underside of the wheel collides with the curb (side impact) and the underside of the wheel is pressed down by the curb, excessive moment load can sometimes be applied to the wheel bearing assembly. This moment load acts on the inner member via the wheel mounting flange. This load acts by pressing the axial end of the inner member downward.

[0010] When such a moment load is applied to the inner component, an excessive load (rolling element load) is applied to the first ball located below the central axis of the bearing assembly, among the multiple first balls positioned on the axial side (wheel side). As a result, the likelihood of indentation occurring on the raceway surface on the axial side where the first ball rolls increases.

[0011] Furthermore, when an excessive torque load as described above is applied to the inner component, the contact angle of the first ball located below the central axis temporarily increases. Conversely, the contact angle of the second ball located below the central axis temporarily decreases.

[0012] Typically, the contact angles of the first and second balls are set to the same value. Therefore, when a torque load as described above is applied to the inner component, the contact angle of the first ball is relatively larger than that of the second ball. As the contact angle of the first ball further increases, the allowable radial load on the first ball decreases relatively, and the load concentrates on the first ball, thereby contributing to the formation of indentations on the raceway surface on the axial side.

[0013] When indentations occur on the raceway surface, they can cause noise, raceway surface peeling, and other issues. Therefore, countermeasures are desired to suppress the formation of such indentations.

[0014] Solution for solving the problem

[0015] The wheel bearing device of the present invention comprises: an inner square member having a wheel mounting flange on one axial side and a double row of inner raceway surfaces on the other axial side; an outer square member having a double row of outer raceway surfaces opposite to the double row of inner raceway surfaces; a plurality of first balls disposed between a first inner raceway surface on one axial side of the double row of inner raceway surfaces and a first outer raceway surface on one axial side of the double row of outer raceway surfaces; and a plurality of second balls disposed between a second inner raceway surface on the other axial side of the double row of inner raceway surfaces and a second outer raceway surface on the other axial side of the double row of outer raceway surfaces, wherein the plurality of first balls and the plurality of second balls have the same diameter, and the contact angle of the plurality of first balls is smaller than the contact angle of the plurality of second balls.

[0016] Invention Effects

[0017] According to this disclosure, it is possible to suppress the formation of indentations on the raceway surface. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of a wheel bearing assembly.

[0019] Figure 2 This is a diagram showing the installation flanges on the vehicle body viewed from the inside of the vehicle along the central axis.

[0020] Figure 3 This is a sectional view of the main parts of the bearing assembly.

[0021] Figure 4 This is a cross-sectional view of a wheel bearing assembly used to illustrate a collision between the lower side of the wheel and the curb. Detailed Implementation

[0022] First, the implementation methods will be described by listing them.

[0023] [Summary of Implementation Methods]

[0024] (1) The wheel bearing device of the embodiment includes: an inner square member having a wheel mounting flange on one axial side and a double row of inner raceway surfaces on the other axial side; an outer square member having a double row of outer raceway surfaces opposite to the double row of inner raceway surfaces; a plurality of first balls disposed between the first inner raceway surface on one axial side of the double row of inner raceway surfaces and the first outer raceway surface on one axial side of the double row of outer raceway surfaces; and a plurality of second balls disposed between the second inner raceway surface on the other axial side of the double row of inner raceway surfaces and the second outer raceway surface on the other axial side of the double row of outer raceway surfaces, wherein the plurality of first balls and the plurality of second balls have the same diameter, and the contact angle of the plurality of first balls is smaller than the contact angle of the plurality of second balls.

[0025] According to the above structure, even if the lower side of the wheel collides with the curb, and an excessive moment load is applied to the inner component, causing a temporary increase in the contact angle of the first ball, the difference between the contact angles of the first and second balls can be suppressed because the contact angles of the multiple first balls are smaller than those of the multiple second balls. As a result, the relative decrease in the allowable radial load caused by the multiple first balls can be suppressed, the concentration of load on the first balls can be suppressed, and indentations on the first inner and first outer raceway surfaces can be suppressed.

[0026] (2) In the above-mentioned wheel bearing device, it is preferable that the pitch circle diameter of the plurality of first balls is larger than the pitch circle diameter of the plurality of second balls. In this case, the allowable load for the load acting on the plurality of first balls can be increased, and the indentation of the first inner raceway surface and the first outer raceway surface can be effectively suppressed.

[0027] Furthermore, if the contact angle of the multiple first balls is reduced, there is a concern that the allowable axial load will decrease, and the bearing life due to normal use will decrease. Therefore, there is a concern that the bearing life of the multiple first balls, the first outer raceway surface, and the first inner raceway surface will be lower than that of the multiple second balls, the second outer raceway surface, and the second inner raceway surface.

[0028] In this regard, by making the pitch circle diameter of the plurality of first balls larger than that of the plurality of second balls, the allowable load for the loads acting on the plurality of first balls is increased, thus compensating for the relative decrease in life of the plurality of first balls, the first outer raceway surface, and the first inner raceway surface caused by changes in the contact angle. As a result, the lifespan decrease of the wheel bearing assembly as a whole can be suppressed.

[0029] (3) In the above-mentioned wheel bearing device, preferably the axial position of the intersection point between the first line of action of the load acting on the plurality of first balls and the second line of action of the load acting on the plurality of second balls is located on the axial side closer to the axial center between the axial position of the bottom of the first outer raceway surface and the axial position of the bottom of the second outer raceway surface.

[0030] A plurality of contact angles for the first balls are formed between the first line of action of the load acting on the plurality of first balls and a plane perpendicular to the central axis of the wheel bearing assembly. Similarly, a plurality of contact angles for the second balls are formed between the second line of action of the load acting on the plurality of second balls and a plane perpendicular to the central axis of the wheel bearing assembly. Thus, the axial position of the intersection point between the first and second lines of action is located axially closer to the axial center than the axial center between the bottom of the first outer raceway surface and the bottom of the second outer raceway surface. Therefore, the contact angles of the plurality of first balls are set to be smaller than the contact angles of the plurality of second balls.

[0031] (4) In addition, in this case, it is preferred that the outer component has a vehicle body mounting flange on its outer periphery for mounting the outer component to the vehicle body, and the axial position of the axial center of the vehicle body mounting flange is closer to the axial position of the bottom of the first outer raceway than the axial position of the bottom of the second outer raceway surface.

[0032] In this case, for example, compared to the case where the body mounting flange is located at the end on the opposite side of the outer member's axial direction, the axial position of the body mounting flange is closer to the axial position of the wheel mounting flange to which the load is applied. Therefore, the moment load acting on the wheel bearing assembly via the wheel mounting flange when the wheel's side lateral side collides with the curb can be reduced, and the formation of indentations on the first inner raceway surface and the first outer raceway surface can be more effectively suppressed.

[0033] (5) Alternatively, the outer component may have a vehicle body mounting flange on its outer periphery, which is used to mount the outer component to the vehicle body, and the axial position of the axial center of the vehicle body mounting flange is located on the axial side of the axial center between the axial position of the bottom of the first outer raceway surface and the axial position of the bottom of the second outer raceway surface.

[0034] In this case, compared to the case where the body mounting flange is located at the end on the opposite side of the outer member's axial direction, the axial position of the body mounting flange is closer to the axial position of the wheel mounting flange to which the load is applied. Therefore, the moment load acting on the wheel bearing assembly via the wheel mounting flange when the wheel's side lateral side collides with the curb can be reduced, and indentations on the first inner and first outer raceway surfaces can be more effectively suppressed.

[0035] (6) In addition, it is preferable that the axial position of the intersection point is located on one side of the axial position of the axial center of the vehicle body mounting flange.

[0036] In this situation, when the lower side of the wheel collides with the curb and the contact angle of the first ball temporarily increases, the axial position of the intersection point is close to the axial center of the vehicle body mounting flange and the axial center of the bearing. Therefore, the load transmitted to the outer component via the two balls can be borne near the vehicle body mounting flange and the bearing center in the outer component. As a result, the situation where the load caused by the lower side of the wheel colliding with the curb is axially deflected and borne by the outer component can be suppressed, and the load transmitted to the outer component can be appropriately borne.

[0037] [Details of the implementation method]

[0038] Hereinafter, preferred embodiments will be described with reference to the accompanying drawings.

[0039] [Overall structure of the bearing assembly]

[0040] Figure 1 This is a cross-sectional view of the wheel bearing assembly 10. The wheel bearing assembly 10 (hereinafter, also simply referred to as bearing assembly 10) is a bearing assembly used in vehicles such as motor vehicles, and is also called a wheel hub unit. The bearing assembly 10 supports the wheel rotatably on a suspension system installed on the body of the motor vehicle.

[0041] The bearing assembly 10 includes an outer ring 11 (outer square member), an inner shaft 12 (inner square member), a plurality of balls 13, a cage 14, and sealing members 15 and 16. The outer ring 11 and the inner shaft 12 are arranged concentrically. In this embodiment, the inner shaft 12 is rotatable relative to the outer ring 11 about a central axis C1. That is, the outer ring 11 is a fixed ring, and the inner shaft 12 is a rotating ring (rotation axis).

[0042] In the following description, the direction along the central axis C1 will be referred to as the "axial direction". The axial direction also includes the direction parallel to the central axis C1. With the bearing assembly 10 installed on the vehicle body, the outer side of the vehicle is referred to as the axial side, and the inner side of the vehicle is referred to as the axial side. The direction orthogonal to the axial direction is referred to as the "radial direction". The direction in which the inner shaft 12 rotates about the central axis C1 is referred to as the "circumferential direction". The bearing assembly 10 can rotatably support the inner shaft 12 on the vehicle body, and the inner shaft 12 fixes a wheel (not shown) and a brake disc (which can be rotated as a whole).

[0043] The outer ring 11 is formed of carbon steel or similar material used in mechanical structures. The outer ring 11 is cylindrical in shape and has a body mounting flange 11b on its outer circumferential surface 11a. The body mounting flange 11b is a component used to mount the outer ring 11 to the vehicle body.

[0044] Figure 2 This is a diagram showing the installation flange 11b of the vehicle body viewed from the inside of the vehicle along the central axis C1.

[0045] like Figure 2 As shown, the vehicle body mounting flange 11b has a plurality of protrusions 11b1 arranged circumferentially. The plurality of protrusions 11b1 (four in the illustration) protrude from the outer peripheral surface 11a.

[0046] Each protrusion 11b1 has a through hole 11b2 parallel to the central axis C1. Bolts for fixing the outer ring 11 to the suspension device on the vehicle body side are inserted through the through hole 11b2.

[0047] It should be noted that in this embodiment, the multiple protrusions 11b1 are arranged symmetrically along the vertical direction, but they can also be arranged at equal intervals along the circumferential direction. Moreover, the number of protrusions 11b1 can be more or less.

[0048] like Figure 1 As shown, the inner circumferential surface of the outer ring 11 is provided with two rows of outer raceway surfaces 17. The two rows of outer raceway surfaces 17 include a first outer raceway surface 17a and a second outer raceway surface 17b. The first outer raceway surface 17a is located on the axial side relative to the second outer raceway surface 17b. Moreover, the outer diameter of the first outer raceway surface 17a is larger than the outer diameter of the second outer raceway surface 17b.

[0049] The inner shaft 12 is formed of carbon steel or the like for mechanical structures. The inner shaft 12 has a shaft member 18 and an inner ring 19. The shaft member 18 has a main body 18a extending axially and a wheel mounting flange 18b projecting radially outward from the main body 18a. The main body 18a and the wheel mounting flange 18b are integral. The wheel mounting flange 18b is located on one axial side of the main body 18a. A wheel and a brake disc (not shown) are mounted on the wheel mounting flange 18b.

[0050] The inner ring 19 is a ring-shaped component made of carbon steel or similar materials used in mechanical structures. The inner ring 19 is fixed to the end of the shaft component 18 on the other side of the axial direction.

[0051] A small diameter portion 18c, with an outer diameter smaller than other parts of the main body portion 18a, is provided on the other axial side of the shaft member 18. An inner ring 19 is pressed into the small diameter portion 18c from the other axial side, fitting into the outer circumferential surface of the small diameter portion 18c. The end portion 18d on the other axial side of the shaft member 18 is riveted by radially outward plastic deformation. Thus, the inner ring 19 is fixed to the shaft member 18.

[0052] The outer circumferential surface of the inner shaft 12 is provided with a double row of inner raceway surfaces 20. The double row of inner raceway surfaces 20 includes a first inner raceway surface 20a and a second inner raceway surface 20b.

[0053] The first inner raceway surface 20a is disposed on the outer peripheral surface of the main body portion 18a of the shaft member 18. The first inner raceway surface 20a is opposite to the first outer raceway surface 17a.

[0054] The second inner raceway surface 20b is disposed on the outer peripheral surface of the inner ring 19. The second inner raceway surface 20b is opposite to the second outer raceway surface 17b.

[0055] Therefore, the first inner raceway surface 20a is located on the axial side compared to the second inner raceway surface 20b.

[0056] The plurality of balls 13 are balls formed of bearing steel or the like. The plurality of balls 13 include a plurality of first balls 13a and a plurality of second balls 13b.

[0057] Multiple first balls 13a are disposed between the first outer raceway surface 17a and the first inner raceway surface 20a.

[0058] Multiple second balls 13b are disposed between the second outer raceway surface 17b and the second inner raceway surface 20b.

[0059] The diameter of the plurality of first balls 13a is the same as the diameter of the plurality of second balls 13b.

[0060] Multiple balls 13 make point contact with the outer raceway surfaces 17a, 17b and the inner raceway surfaces 20a, 20b at a predetermined contact angle. That is, the bearing assembly 10 includes a double row of angular contact ball bearings, with the outer ring 11 and the inner shaft 12 forming raceway rings respectively.

[0061] The cage 14 is a ring-shaped component formed of resin. The cage 14 holds the multiple balls 13 in each row with a predetermined circumferential interval.

[0062] Sealing member 15 is installed between the axial end of the outer ring 11 and the main body 18a. Sealing member 16 is installed between the axial end of the outer ring 11 and the inner ring 19. Sealing members 15 and 16 function to prevent impurities such as mud and water from entering the annular space formed between the outer ring 11 and the inner shaft 12, and to seal the space to prevent lubricant leakage.

[0063] Figure 3 This is a sectional view of the main parts of the bearing assembly 10.

[0064] like Figure 3 As shown, the pitch circle diameter D1 of the plurality of first balls 13a is greater than the pitch circle diameter D2 of the plurality of second balls 13b.

[0065] Furthermore, in this embodiment, the contact angle θa of the plurality of first balls 13a is 30 degrees, and the contact angle θb of the plurality of second balls 13b is 40 degrees. Thus, the contact angle θa of the plurality of first balls 13a is smaller than the contact angle θb of the plurality of second balls 13b.

[0066] It should be noted that the contact angle θa of the plurality of first balls 13a is set in the range of 25 to 35 degrees. Furthermore, the contact angle θb of the plurality of second balls 13b is set in the range of 35 to 45 degrees.

[0067] Here, the contact angle of the ball 13 refers to the angle formed by the line of action of the resultant force of the force transmitted to the ball 13 through the outer ring 11 and the inner shaft 12 from the plane (radial plane) perpendicular to the central axis C1.

[0068] The first line of action L1 of the load acting on the first ball 13a is a straight line passing through the contact portion 31 of the first ball 13a that contacts the first outer raceway surface 17a, the contact portion 32 of the first ball 13a that contacts the first inner raceway surface 20a, and the center 33 of the first ball 13a.

[0069] The contact angle θa of the first ball 13a is the angle formed by the first line of action L1 and the straight line L2 that passes through the center 33 of the first ball 13a and is orthogonal to the central axis C1.

[0070] Furthermore, the second line of action L3 of the load acting on the second ball 13b is a straight line passing through the contact portion 41 of the second ball 13b that contacts the second outer raceway surface 17b, the contact portion 42 of the second ball 13b that contacts the second inner raceway surface 20b, and the center 43 of the second ball 13b.

[0071] The contact angle θb of the second ball 13b is the angle formed by the second line of action L3 and the straight line L4 that passes through the center 43 of the second ball 13b and is orthogonal to the central axis C1.

[0072] In addition, the axial position of the intersection point P1 of the first line of action L1 and the second line of action L3 is located on the axial side closer to the axial center than the axial position between the axial position of the first outer raceway surface 17a and the axial position of the second outer raceway surface 17b.

[0073] More specifically, line L2 passes through the bottom 51 of the first outer raceway surface 17a. Furthermore, line L4 passes through the bottom 52 of the second outer raceway surface 17b.

[0074] Figure 3 In the diagram, the axial centerline LC is orthogonal to the central axis C1 and is located at the axial center between lines L2 and L4. The intersection point P1 is located on the axial side closer to the centerline LC.

[0075] Therefore, the axial position of the intersection point P1 is located on the axial side of the axial center between the axial position of the bottom 51 of the first outer raceway surface 17a and the axial position of the bottom 52 of the second outer raceway surface 17b.

[0076] In this embodiment, the axial position of the vehicle body mounting flange 11b is located between straight lines L2 and L4.

[0077] More specifically, the straight line LF, which represents the axial center of the body mounting flange 11b, is a straight line orthogonal to the central axis C1 and passes through the axial center of the body mounting flange 11b. The straight line LF is located on the axial side further than the axial centerline LC.

[0078] Therefore, the axial position of the axial center of the vehicle body mounting flange 11b is located on the axial side of the axial center between the axial position of the bottom 51 of the first outer raceway surface 17a and the axial position of the bottom 52 of the second outer raceway surface 17b.

[0079] In other words, the axial position of the center of the vehicle body mounting flange 11b is closer to the axial position of the bottom 51 of the first outer raceway surface 17a than the axial position of the bottom 52 of the second outer raceway surface 17b.

[0080] Furthermore, the axial position of the intersection point P1 is located on the axial side of the line LF.

[0081] Therefore, the axial position of the intersection point P1 is located on one side of the axial position relative to the axial center of the vehicle body mounting flange 11b.

[0082] [Regarding the situation where the lower side of the wheel collided with the curb]

[0083] Figure 4 This is a cross-sectional view of a wheel bearing assembly 10 used to illustrate a situation where the lower side of the wheel collides with a curb.

[0084] For example, suppose the lower side of wheel W collides with the curb. Then, an excessive moment load acts on the inner axle 12 via the wheel mounting flange 18b in the direction indicated by arrow Y1.

[0085] When such an excessive torque load is applied to the inner shaft 12, a large load is applied to the first ball 13a1 located below the central shaft C1 among the multiple first balls 13a.

[0086] Furthermore, when an excessive torque load as described above is applied, the contact angle θa of the first ball 13a1 temporarily increases. Conversely, the contact angle θb of the second ball 13b1 located below the central axis C1 among the plurality of second balls 13b temporarily decreases.

[0087] When the aforementioned torque load is applied to the inner shaft 12, and the contact angle θa of the first ball 13a1 further increases, there is concern that the allowable radial load based on the first ball 13a1 will decrease relatively, and the indentation on the first outer raceway surface 17a will be promoted due to the load being concentrated on the first ball 13a1.

[0088] In this embodiment, the contact angle θa of the plurality of first balls 13a is smaller than the contact angle θb of the plurality of second balls 13b. Therefore, even if the lower side of the wheel W collides with the curb and the contact angle θa of the first balls 13a1 temporarily increases, the increase in the difference between the contact angle θa of the first balls 13a and the contact angle θb of the second balls 13b can be suppressed. As a result, the relative decrease in radial allowable load caused by the plurality of first balls 13a can be suppressed, the load concentration on the first balls 13a can be suppressed, and the formation of indentations on the first inner raceway surface 20a and the first outer raceway surface 17a can be suppressed.

[0089] In addition, in this embodiment, by making the contact angle θa of the plurality of first balls 13a smaller than the contact angle θb of the plurality of second balls 13b, slippage between the plurality of first balls 13a and the first outer raceway surface 17a and the first inner raceway surface 20a can be suppressed, thereby suppressing the overall temperature rise of the wheel bearing assembly 10 and reducing the rotational torque.

[0090] In addition, in this embodiment, the pitch circle diameter D1 of the plurality of first balls 13a is larger than the pitch circle diameter D2 of the plurality of second balls 13b, so that the allowable load for the load acting on the plurality of first balls 13a is greater than the allowable load for the load acting on the plurality of second balls 13b.

[0091] Therefore, it is possible to effectively suppress the formation of indentations on the first inner raceway surface 20a and the first outer raceway surface 17a.

[0092] Furthermore, if the contact angle θa of the multiple first balls 13a is reduced, there is concern that the allowable load for axial loads will decrease, and the bearing life will decrease due to normal use.

[0093] Therefore, there is concern that the bearing life of the plurality of first balls 13a and raceway surfaces 17a, 20a is lower than that of the plurality of second balls 13b and raceway surfaces 17b, 20b.

[0094] In this embodiment, the pitch circle diameter D1 of the plurality of first balls 13a is made larger than the pitch circle diameter D2 of the plurality of second balls 13b, thereby increasing the allowable load for the loads acting on the plurality of first balls 13a. This compensates for the relative decrease in lifespan of the plurality of first balls 13a and raceway surfaces 17a, 20a caused by changes in the contact angle θa. As a result, the lifespan decrease of the wheel bearing assembly 10 as a whole can be suppressed.

[0095] In addition, in this embodiment, the axial position (straight line LF) of the axial center of the vehicle body mounting flange 11b is located on the axial side of the axial center between the axial position of the bottom 51 of the first outer raceway surface 17a and the axial position of the bottom 52 of the second outer raceway surface 17b.

[0096] In other words, the axial position (straight line LF) of the axial center of the body mounting flange 11b is closer to the axial position of the bottom 51 of the first outer raceway surface 17a than the axial position of the bottom 52 of the second outer raceway surface 17b.

[0097] Therefore, for example, compared to the case where the body mounting flange 11b is located at the end of the outer ring 11 on the inner side of the vehicle, the axial position of the body mounting flange 11b is closer to the axial position of the wheel mounting flange 18b to which the load is applied. This reduces the torque load acting on the bearing assembly 10 as a whole via the wheel mounting flange 18b when the lower side of the wheel W collides with the curb. As a result, it is more effective to suppress indentations on the first inner raceway surface 20a and the first outer raceway surface 17a.

[0098] Furthermore, by positioning the body mounting flange 11b at an axial position close to the bottom 51 of the first outer raceway surface 17a, the intersection point P1 can be positioned axially close to the body mounting flange 11b. Therefore, except in cases where the lower side of the wheel W collides with the curb, the load transmitted from the inner axle 12 to the outer ring 11 via the two balls 13 can be borne at a position in the outer ring 11 close to the body mounting flange 11b. Thus, except in cases where the lower side of the wheel W collides with the curb, the load transmitted from the inner axle 12 to the outer ring 11 via the two balls 13 can be appropriately borne.

[0099] Furthermore, in this embodiment, the axial position of the intersection point P1 is located axially to one side of the axial position (straight line LF) of the axial center of the vehicle mounting flange 11b. Therefore, when the lower side of the wheel W collides with the curb and the contact angle θa of the first ball 13a1 temporarily increases, the axial position of the intersection point P1 is close to the straight line LF and the axial centerline LC. As a result, the load transmitted to the outer ring 11 via the two balls 13a and 13b can be borne near the vehicle mounting flange 11b and the axial centerline LC in the outer ring 11. Consequently, it is possible to suppress the situation where the load caused by the collision between the lower side of the wheel W and the curb is axially deflected and borne by the outer ring 11.

[0100] 〔other〕

[0101] The implementation methods disclosed herein are illustrative of all points and are not limited thereto.

[0102] For example, in this embodiment, the axial position of the axial center of the vehicle body mounting flange 11b is shown to be located on one side of the axial center between the axial position of the bottom 51 of the first outer raceway surface 17a and the axial position of the bottom 52 of the second outer raceway surface 17b. However, the axial position of the axial center of the vehicle body mounting flange 11b may also be located on the other side of the axial center between the axial position of the bottom 51 of the first outer raceway surface 17a and the axial position of the bottom 52 of the second outer raceway surface 17b.

[0103] Furthermore, in this embodiment, the axial position of the intersection point P1 is illustrated as being located on one side axially relative to the axial position of the center of the vehicle body mounting flange 11b. However, the axial position of the intersection point P1 can also be located on the other side axially relative to the center of the vehicle body mounting flange 11b. In other words, the axial position of the center of the vehicle body mounting flange 11b can also be located on one side axially relative to the intersection point P1.

[0104] The scope of this invention is not limited to the embodiments described above, but includes all modifications within the scope of those equivalent to the structures described in the claims.

[0105] Label Explanation

[0106] 10. Wheel bearing assembly

[0107] 11 Outer ring

[0108] 11a Outer peripheral surface

[0109] 11b Body Mounting Flange

[0110] 11b1 protrusion

[0111] 11b2 Through Hole

[0112] 12 Inner Shaft

[0113] 13 Ball bearings

[0114] 13a, 13a1 First Ball

[0115] 13b, 13b1 second ball bearing

[0116] 14. Cage

[0117] 15 Sealing components

[0118] 16 Sealing components

[0119] 17 Outer raceway surface

[0120] 17a First outer raceway surface

[0121] 17b Second outer raceway surface

[0122] 18 shaft components

[0123] 18a Main body

[0124] 18b Wheel mounting flange

[0125] 18c small diameter section

[0126] 18d end

[0127] 19 Inner Circle

[0128] 20 Inner raceway surface

[0129] 20a First inner raceway surface

[0130] 20b Second inner raceway surface

[0131] 31 Contact Part

[0132] 32 Contact Part

[0133] 33 Centers

[0134] 41 Contact Part

[0135] 42 Contact Part

[0136] 43 Center

[0137] 51 Bottom

[0138] 52 Bottom

[0139] C1 Central Axis

[0140] D1 Pitch circle diameter

[0141] D2 Pitch circle diameter

[0142] L1 First line of action

[0143] L2 straight line

[0144] L3 Second line of action

[0145] L4 straight line

[0146] LC axial centerline

[0147] LF straight line

[0148] P1 intersection

[0149] W wheel

[0150] Y1 arrow

[0151] Y2 arrow

[0152] θa Contact angle

[0153] θb contact angle

Claims

1. A wheel bearing device, comprising: The inner square member has a wheel mounting flange on one axial side and a double row of inner raceway surfaces on the other axial side. The outer component has a double-row outer raceway surface opposite to the inner raceway surface of the double rows; A plurality of first balls are disposed between a first inner raceway surface on one axial side of the inner raceway surface of the double rows and a first outer raceway surface on one axial side of the outer raceway surface of the double rows; and A plurality of second balls are disposed between a second inner raceway surface on the opposite axial side of the inner raceway surface of the double rows and a second outer raceway surface on the opposite axial side of the outer raceway surface of the double rows. The plurality of first balls and the plurality of second balls have the same diameter. The contact angle of the plurality of first balls is smaller than the contact angle of the plurality of second balls. The axial position of the intersection point between the first line of action of the load acting on the plurality of first balls and the second line of action of the load acting on the plurality of second balls is located axially to one side of the axial center between the axial position of the bottom of the first outer raceway surface and the axial position of the bottom of the second outer raceway surface. The outer component has a body mounting flange on its outer periphery for mounting the outer component to the vehicle body. The axial position of the center of the vehicle body mounting flange is located on one side of the axial center between the axial positions of the bottom of the first outer raceway surface and the bottom of the second outer raceway surface. The axial position of the intersection point is located on one side of the axial position relative to the axial center of the vehicle body mounting flange.

2. The wheel bearing device according to claim 1, wherein, The pitch circle diameter of the plurality of first balls is larger than the pitch circle diameter of the plurality of second balls.

3. The wheel bearing assembly according to claim 1 or 2, wherein, The outer component has a body mounting flange on its outer periphery for mounting the outer component to the vehicle body. The axial position of the center of the vehicle body mounting flange is closer to the axial position of the bottom of the first outer raceway than the axial position of the bottom of the second outer raceway surface.

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