Wheel bearing device

The present invention relates to a wheel bearing device that rotatably supports wheels of an automobile or the like.

Conventionally, as a wheel bearing device for supporting drive wheels, the one shown in FIG. 5 has been proposed (for example, Patent Document 1). This is a hub in which balls 25 are interposed in multiple rows between the rolling surfaces 23 and 24 of the outer member 21 and the inner member 22 facing each other, and the inner member 22 has a wheel mounting hub flange 29a on the outer circumference. It is composed of a ring 29 and an inner ring 30 fitted to the outer circumference of the inboard side end of the hub wheel 29. The inner ring 30 fits into the step portion 35 provided on the hub ring 29. The stem portion 33a of the outer ring 33 of the constant velocity joint is inserted into the central hole 31 of the hub ring 30 and spline-fitted, and the step surface 33b of the outer ring 33 of the constant velocity joint is pressed against the inboard side end surface 30a of the inner ring 30. Be done. In this state, by screwing the nut 34 into the tip of the stem portion 33a, the width of the inner member 22 is tightened by the constant velocity joint outer ring 33 and the nut 34.

In this type of wheel bearing device, it is desired to prevent the inner ring 30 fitted to the hub wheel 29 from being inadvertently pulled out before the bearing device is assembled to the actual vehicle. In response to such a request, in the proposed example of the figure, a step portion 36 is formed on the inner circumference of the inboard side end portion of the inner ring 30, and the step portion 36 is provided on the entire circumference of the end portion of the hub ring 29. It is suppressed by the tightening part 29b.

The proposed example in the figure is for the following improvements. That is, in the conventional general wheel bearing device for supporting drive wheels, the end face of the inner ring 30 is directly pressed by the crimping portion 29b without providing the step portion 36 on the inner ring 30 of the proposed example of FIG. There is. In that case, since the crimping portion 29b protrudes in the axial direction from the inner ring 30, additional machining is required for the crimping portion 29b to serve as a contact surface with the constant velocity joint outer ring 33 after the crimping process. .. In the proposed example of FIG. 5, the crimping portion 29b does not protrude outside the step portion 36 of the inner ring 30, and the end face of the inner ring 30 can be used as the abutting surface, so that no additional machining is required.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 9-164803</text></patcit>

<p> However, the proposed example in the figure has the following problems. (1) In crimping, the crimping tool interferes with the inner diameter of the inner ring 30, making machining difficult. In this case, unlike the normal swing crimping, the crimping outer diameter portion cannot be suppressed, so that the crimping element is high in the axial direction. As a result, the amount of expansion of the shaft portion of the hub wheel 29 becomes excessive, and the hoop stress generated in the inner ring 30 becomes high. Excessive hoop stress causes cracking and premature peeling of the inner ring 30. (2) If the inner ring 30 is provided with a large step portion 36, the abutting area between the inner ring 30 and the step surface 33b of the constant velocity joint outer ring 33 becomes small, and the contact surface pressure becomes excessive. That is, as described above, the inner member 22 is width-tightened by the constant velocity joint outer ring 33 and the nut 34. At this time, the end surface of the inner ring 30 and the step surface 33b of the constant velocity joint outer ring 33 come into contact with each other. However, if the area of the end surface of the inner ring 30 is small, the contact surface pressure increases, causing wear and abnormal noise in the actual vehicle. Causes. In the wheel bearing device in which the hub wheel 29 is not provided with the crimping portion 29b, the above-mentioned problems such as deformation of the inner ring 30 and excessive surface pressure do not occur, but from the shipment of the bearing to the assembly to the vehicle, The inner ring may be inadvertently pulled out due to vibration or the like.</p><p> An object of the present invention is to provide a wheel bearing device that can minimize the deformation of the inner ring and the hoop stress generated in the inner ring, and prevent the inner ring from coming off due to vibration or the like from the shipment of the bearing to the assembly to the vehicle. To provide.</p>

<p> The wheel bearing device of the present invention includes an outer member having a double row of rolling surfaces on the inner circumference, an inner member having a rolling surface facing each rolling surface on the outer circumference, and these facing rolling surfaces. A hub wheel having a rolling element having a double-row rolling surface interposed between the surfaces, and the inner member having a flange for mounting a wheel, and an inner ring fitted to the outer periphery of the inboard side portion of the hub wheel. Therefore, the rolling surface of each row is formed on the hub wheel and the inner ring, and the application is applied to a wheel bearing device that rotatably supports a wheel serving as a driving wheel with respect to a vehicle body. In the above configuration, an annular recess is provided on the outer periphery near the inboard side end of the hub ring, and the portion of the hub ring on the inboard side of the annular recess is plastically deformed to the outer diameter side to form the plastically deformed portion. The inner ring is prevented from coming off by facing the surface of the inner ring facing the inboard side. The plastically deformed portion may face the surface of the inner ring facing the inboard side. For example, the plastically deformed portion may be pressed against the surface of the inner ring facing the inboard side, or the plastically deformed portion may be pressed against the surface of the inner ring facing the inboard side. A gap may be provided between the inner ring and the surface facing the inboard side. According to this configuration, the end of the hub wheel on the inboard side is plastically deformed to the outer diameter side, and the plastically deformed part is made to face the surface of the inner ring facing the inboard side. It is possible to prevent the inner ring from inadvertently coming off the hub ring due to vibration or the like. In this case, an annular recess is provided on the outer periphery near the inboard side end of the hub ring, and the portion on the inboard side of the annular recess is plastically deformed. Plastic deformation processing to the outer diameter side can be easily performed. Therefore, it is possible to avoid deforming the inner ring by the crimping process, and it is possible to prevent a large hoop stress from being generated in the inner ring due to an excessive expansion amount of the hub wheel axle portion.</p><p> In the present invention, a step portion having a diameter larger than that of the inner diameter surface is provided on the entire circumference of the inboard side end on the inner diameter surface of the inner ring, and the plastically deformed portion of the hub ring is formed on the inboard in the step portion of the inner ring. It may be opposed only to the side facing side. When the stepped portion is provided, the plastically deformed portion does not protrude outside the stepped portion of the inner ring, and the end surface of the inner ring can be used as an abutting surface against the stepped surface of the constant velocity joint outer ring, so that the plastically deformed portion can be used. No additional machining is required to flatten. Further, since the plastically deformed portion engages only with the end surface of the step portion facing the inboard side and does not contact the inner diameter surface of the step portion, the generation of hoop stress can be prevented more reliably.</p><p> In the present invention, the plastically deformed portion of the hub ring may not protrude toward the inboard side from the inner ring. Assuming that the plastically deformed portion of the hub ring does not protrude from the inner ring even if the step portion is not necessarily provided, the end surface of the inner ring can be used as an abutting surface with the outer ring of the constant velocity joint and thrusts into the plastically deformed portion. No additional machining is required to secure the contact surface.</p>

<p> The wheel bearing device of the present invention comprises a hub ring whose inner member has a wheel mounting flange and an inner ring fitted to the outer periphery of the inboard side portion of the hub ring, and each row is formed on the hub ring and the inner ring. In the wheel bearing device on which the rolling surface is formed, an annular recess is provided on the outer periphery near the inboard side end of the hub wheel, and the portion of the hub wheel on the inboard side of the annular recess has an outer diameter. By plastically deforming to the side and making the plastically deformed portion face the surface of the inner ring facing the inboard side, the inner ring is prevented from coming off, so that the deformation of the inner ring and the hoop stress generated in the inner ring are minimized. In addition, it is possible to prevent the inner ring from coming off due to vibration or the like from the shipment of the bearing to the assembly on the vehicle.</p>

A first embodiment of the present invention will be described with reference to FIGS. 1 and 2. This embodiment is a third-generation inner ring rotation type and is applied to a wheel bearing device for supporting drive wheels. In this specification, the side that is closer to the outside in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side that is closer to the center of the vehicle is referred to as the inboard side. This wheel bearing device includes an outer member 1 having a double row of rolling surfaces 3 formed on the inner circumference, an inner member 2 forming a rolling surface 4 facing each of these rolling surfaces 3, and the outer members 2. It is composed of a double-row rolling element 5 interposed between the rolling surfaces 3 and 4 of the square member 1 and the inner member 2. This wheel bearing device is of a double-row angular contact ball bearing type, and the rolling elements 5 are made of balls and are held by cages 6 in each row. Each of the rolling surfaces 3 and 4 has an arcuate cross section, and each of the rolling surfaces 3 and 4 is formed so that the ball contact angles are back-to-back. Both ends of the bearing space between the outer member 1 and the inner member 2 are sealed by seals 7 and 8, respectively.

The outer member 1 is a member on the fixed side, has a vehicle body mounting flange 1a on the outer circumference, and is an integral part as a whole. The vehicle body mounting flange 1a is fastened to a knuckle installed on the vehicle body (not shown) with bolts (not shown). The inner member 2 is a member on the rotation side, and is composed of a hub ring 9 having a flange 9a for mounting wheels on the outer circumference and an inner ring 10 fitted on the outer circumference of the inboard side portion of the hub wheel 9. Therefore, the rolling surface 4 of the outboard side row on the rolling surface 4 of the double row is formed on the hub wheel 9, and the rolling surface 4 of the inboard side row is formed on the inner ring 10. The hub ring 9 has an inner ring fitting surface 9b as a stepped portion on the outer periphery of the inboard side portion, and the inner ring 10 is fitted to the inner ring fitting surface 9b. The hub ring 9 has a central hole 14, and the rolling surface 4 thereof is an induction hardened surface hardened surface. Further, the entire inner ring 10 from the surface to the core is hardened by quenching.

As shown by enlarging a part in FIG. 1 (B), a step portion 10b having a diameter larger than that of the inner diameter surface 10a is provided on the entire circumference of the inboard side end of the inner ring 10 on the inner diameter surface 10a. There is. An annular recess 11 is provided on the outer periphery of the hub ring 9 near the inboard side end, and the portion of the hub ring 9 on the tip side of the annular recess 11, that is, the portion on the inboard side is directed to the outer diameter side. The inner ring 10 is prevented from coming off by being plastically deformed and the plastically deformed portion 12 facing the surface of the inner ring 10 facing the inboard side. Specifically, in the state before plastic working shown in FIG. 2 (A), the annular recess 11 of the hub ring 9 has a side surface 11a facing the outboard side and a surface 10ba whose side surface 11a faces the inboard side of the inner ring step portion 10b. It is provided at a position slightly closer to the inboard side than. Further, in this state, the end face on the inboard side of the hub wheel 9 is positioned to be slightly closer to the outboard side than the end face on the inboard side of the inner ring 10. From this state before processing, as shown in FIG. 2 (B), the portion of the hub ring 9 on the inboard side of the annular recess 11 is plastically deformed to the outer diameter side by pushing the jig 13 toward the inner diameter surface side thereof. Let me. The jig 13 is said to have a tapered outer diameter surface (taper angle θ) with a small diameter on the tip side. As a result, as shown in FIG. 2C, the side surface 11a of the annular recess 11 facing the outboard side faces only the surface 10ba of the inner ring step portion 10b facing the inboard side. At this time, the plastically deformed portion 12 of the hub ring 9 does not protrude toward the inboard side from the inner ring 10. Further, a slight gap δ is secured between the outer diameter surface of the plastically deformed portion 12 of the hub ring 9 and the step portion 10b of the inner ring 10. In the examples of FIGS. (C) and 1 (B), the plastic deformation portion 12 is pressed against the surface 10ba of the inner ring 10 facing the inboard side. However, as shown in FIG. 4, the plastic deformation portion 12 is pressed against the surface 10ba. A gap δ2 may be provided between 12 and the surface 10ba of the inner ring 10 facing the inboard side.

In assembling this wheel bearing device to a vehicle, the stem portion 16a of the outer ring 16 which is one of the joint members of the constant velocity joint 15 is inserted into the central hole 14 of the hub wheel 9 and spline-fitted to fit the stem. By tightening the nut 17 screwed into the tip of the portion 16a, the constant velocity joint outer ring 16 is coupled to the inner member 2. At this time, the step surface 16b provided on the constant velocity joint outer ring 16 facing the outboard side is pressed against the end surface 10c facing the inboard side of the inner ring 10, and the inner member 2 is formed by the constant velocity joint outer ring 16 and the nut 17. Is tightened. The wheel mounting flange 9a is located at the outboard side end of the hub wheel 9, and the wheels (none of which are shown) to be the driving wheels are mounted to the flange 9a via the brake rotor with bolts 18.

According to the wheel bearing device having this configuration, an annular recess 11 is provided on the outer periphery near the inboard side end of the hub wheel 9, and the portion of the hub wheel 9 on the inboard side of the annular recess 11 is plasticized to the outer diameter side. The inner ring 10 is deformed so that the plastically deformed portion 12 faces the surface 10ba of the inner ring 10 facing the inboard side to prevent the inner ring 10 from coming off. It is possible to prevent the inner ring 10 from inadvertently coming off the hub wheel 9. Since the annular recess 11 is provided, the constricted shape of the hub ring 9 formed by the annular recess 11 makes it easy to perform plastic deformation processing to the outer diameter side. Therefore, it is possible to avoid deforming the inner ring 10 by the crimping process. Further, by adjusting the axial position of the annular recess 11 in the hub wheel 9, the position of the plastically deformed portion 12 can be adjusted.

In this embodiment, a step portion 10b having a diameter larger than that of the inner diameter surface 10a is provided on the entire circumference of the inboard side end of the inner ring 10 on the inner diameter surface 10a, and the plastically deformed portion 12 of the hub ring 9 is formed on the step portion. Since it is arranged in 10b and the plastic deformation portion 12 does not protrude toward the inboard side from the inner ring 10, the end surface of the inner ring 10 can be used as the abutting surface with the constant velocity joint outer ring 16. There is no need for additional machining to secure the abutting surface as in the conventional example.

Further, the plastically deformed portion 12 of the hub ring 9 faces only the surface 10ba of the inner ring 10 facing the inboard side in the stepped portion 10b, and is separated from the inner diameter surface of the stepped portion 10b. It is possible to minimize the deformation of the inner ring 10 due to the plastic deformation processing of 12 and the hoop stress generated in the inner ring 10. Even if the inner ring 10 is provided with the stepped portion 10b, the reduction in the flat surface width of the end face of the inner ring 10 can be minimized by setting the stepped portion 10b to the minimum required radial depth. As a result, it is possible to prevent the contact surface pressure between the end surface of the inner ring 10 and the step surface 16b of the constant velocity joint outer ring 16 from becoming large, and eliminate the causes of wear and abnormal noise in the actual vehicle.

In the above embodiment, the annular recess 11 of the hub ring 9 has a rectangular cross section having both side surfaces perpendicular to the outer diameter surface of the hub ring 9, but the present invention is not limited to this, as shown in FIG. For example, an annular recess 11 having an arcuate side surface facing the inboard side may be used. By forming one side surface of the annular recess 11 in an arcuate cross section in this way, it is possible to alleviate the concentration of stress in the annular recess 11 in the plastic working of the end portion of the hub ring 9.

<figref num="1">(A) is a cross-sectional view of the wheel bearing device according to the first embodiment of the present invention, and (B) is an enlarged cross-sectional view of the M portion in (A).</figref><figref num="2">It is explanatory drawing of plastic working of a hub wheel in the bearing device for a wheel.</figref><figref num="3">It is a partial enlarged sectional view which shows the deformation example of the hub ring plastic working part in the bearing device for a wheel.</figref><figref num="4">It is a partially enlarged cross-sectional view which shows the other deformation example of the hub ring plastic working part in the bearing device for a wheel.</figref><figref num="5">It is sectional drawing of the conventional example.</figref>

Code description

1 ... Outer member 2 ... Inner member 3,4 ... Rolling surface 5 ... Rolling body 9 ... Hub wheel 9a ... Flange for wheel mounting 10 ... Inner ring 10a ... inner diameter surface 10b ... stepped part 10ba ... end surface 11 ... annular recess 12 ... plastic deformation part