Wheel bearing device and method for manufacturing wheel bearing device

Abstract

To provide a bearing device for a wheel capable of suppressing vibration in direct advance and also improving a bearing life, and a method for manufacturing the bearing device for a wheel.SOLUTION: A bearing device 1 for a wheel has: an outer ring 2 with double row outside raceway surfaces 2c, 2d formed on its inner periphery; a hub ring 3 and an inner ring 4 respectively having double row inside raceway surfaces 3c, 4a facing the double row outside raceway surfaces 2c, 2d on their outer peripheral surfaces; and double row ball rows 5 and 6 accommodated so as to be rollable between both raceway surfaces of the outer ring 2, the hub ring 3 and the inner ring 4. With at least one of the double row outside raceway surfaces 2c and 2d or at least one of the double row inside raceway surfaces 3c and 4a attached to a vehicle body without any load, a diameter in the direction perpendicular to a direction in which gravity G is applied is larger than a diameter in the direction in which the gravity is applied.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a wheel bearing device and a method for manufacturing a wheel bearing device.

Background Art

[0002] Conventionally, a wheel bearing device that rotatably supports a wheel in a suspension device such as an automobile is known. The wheel bearing device includes an inner ring rotation type in which a hub ring, which is an inner member connected to the wheel, is rotatably supported by an outer member fixed to the vehicle body via rolling elements, and an outer ring rotation type in which an outer ring, which is an outer member connected to the wheel, is rotatably supported by an inner member fixed to the vehicle body via rolling elements.

[0003] In such a wheel bearing device, in the running state of the vehicle, the member on the fixed side may be elastically deformed by an external force from the wheel, and the roundness of the raceway surface of the rolling elements may deteriorate. It is known that the bearing life of the wheel bearing device decreases as the roundness of the raceway surface deteriorates. Therefore, in order to solve such problems, for example, there is a wheel bearing device described in Patent Document 1.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the inner ring rotation type wheel bearing device described in Patent Document 1, several locations on the outer peripheral surface of the outer member are fixed by a chuck, and grinding is performed in a state where the shape of the outer raceway surface is elastically deformed into an elliptical shape with a minor axis in the horizontal direction and a major axis in the vertical direction. In the wheel bearing device processed in this way, when the vehicle turns, the outer member elastically deforms due to the turning load applied, so that the outer raceway surface becomes a shape with an appropriate roundness, and a good turning running state can be maintained. However, in the wheel bearing device, the time ratio of the load in the straight-ahead / stop state is larger than the time ratio of the turning load. Also, just by fixing several locations of the outer member with a chuck and processing, it is difficult to accurately make the roundness of the raceway surface in the desired state when the load is applied.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a wheel bearing device and a method for manufacturing a wheel bearing device that can suppress vibration during straight running and improve the bearing life.

Means for Solving the Problems

[0007] That is, a first invention is a wheel bearing device having a stationary ring in which a double row of stationary side raceway surfaces are formed, a rotating ring in which a double row of rotating side raceway surfaces facing the double row of stationary side raceway surfaces are formed, and a double row of rolling elements rotatably accommodated between both raceway surfaces of the stationary ring and the rotating ring, wherein at least one of the double row of stationary side raceway surfaces has a diameter in a direction perpendicular to the direction in which gravity acts larger than the diameter in the direction in which gravity acts in the posture attached to the vehicle body.

[0008] A second invention is a wheel bearing device in which the stationary side raceway surface is a shape in which the roundness becomes smaller due to elastic deformation when the vehicle is stopped or moving straight ahead.

[0009] The third invention is a method for manufacturing a wheel bearing device having a stationary ring in which a double row of stationary raceway surfaces are formed, a rotating ring in which a double row of rotating raceway surfaces facing the double row of stationary raceway surfaces are formed, and a double row of rolling elements rollably accommodated between both raceway surfaces of the stationary ring and the rotating ring. When the vehicle is stopped or moving straight with the stationary ring attached to the vehicle body, the shape of the elastic deformation of the stationary ring is calculated. A restraining jig is fitted at a position overlapping in the radial direction on at least one of the stationary raceway surfaces, and the stationary raceway surface is machined in a state where the stationary ring is elastically deformed so as to have the calculated shape of elastic deformation.

[0010] The fourth invention is that the restraining jig is composed of an annular member, at least one part is open, fastening means for bringing its ends close to each other is provided, and it has an inner peripheral surface shaped to elastically deform the stationary raceway surface into the calculated shape of elastic deformation with the ends in close contact with each other. It is a method for manufacturing a wheel bearing device in which the outer peripheral surface of the stationary ring is pressed by the inner peripheral surface of the restraining jig by bringing the ends close to each other by the fastening means to elastically deform the stationary ring.

[0011] The fifth invention is that the restraining jig is composed of a shaft-like member, has an outer peripheral surface shaped to elastically deform the stationary ring into the calculated shape of elastic deformation, and the outer peripheral surface of the restraining jig presses the inner peripheral surface of the stationary ring by press-fitting the restraining jig into the stationary ring to elastically deform the stationary ring.

Advantages of the Invention

[0012] As an effect of the present invention, the following effects are obtained.

[0013] That is, in the first invention, when the vehicle is stopped or moving straight, the difference in the diameters of the raceway surfaces in each direction is reduced by the elastic deformation of the raceway surfaces in the direction in which the gravitational force G, which is the direction of the load applied to the wheel bearing device, is applied. Thereby, it is possible to suppress vibration during straight running and improve the bearing life.

[0014] In the second invention, when the vehicle with the highest time ratio is stopped or moving straight, the roundness of the raceway surface is maintained in an appropriate state. Thereby, vibration during straight running can be suppressed and the bearing life can be improved.

[0015] In the third to fifth inventions, due to the fitting of the restraining jig, the entire circumference of the outer member or the inner member is elastically deformed into the shape when the vehicle is stopped or moving straight, so that it is processed into a raceway surface with a desired shape with high precision. Thereby, vibration during straight running can be suppressed and the bearing life can be improved.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0017] Hereinafter, with reference to FIGS. 1 and 2, the inner ring 4-rotation type wheel bearing device 1 which is the first embodiment of the wheel bearing device according to the present invention will be described.

[0018] As shown in FIG. 1, the wheel bearing device 1 rotatably supports a wheel in a suspension device of a vehicle such as an automobile. The wheel bearing device 1 includes an outer ring 2 as an outer member, a hub ring 3 as an inner member, an inner ring 4, two inner side ball rows 5 as rolling rows, an outer side ball row 6, an inner side seal member 9, and an outer side seal member 10. The wheel bearing device 1 is an inner ring rotation type wheel bearing device in which the outer ring 2 as an outer member is a stationary ring, and the hub ring 3 and the inner ring 4 as inner members are rotating rings. Here, the inner side represents the vehicle body side of the wheel bearing device 1 when attached to the vehicle body, and the outer side represents the wheel side of the wheel bearing device 1 when attached to the vehicle body. Also, the axial direction represents the direction along the rotation axis of the wheel bearing device 1.

[0019] The outer ring 2 is made of, for example, medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C. An inner side opening 2a into which the inner side seal member 9 can be fitted is formed at the inner side end of the outer ring 2. An outer side opening 2b into which the outer side seal member 10 can be fitted is formed at the outer side end of the outer ring 2. An inner side outer raceway surface 2c and an outer side outer raceway surface 2d are formed in an annular shape on the inner peripheral surface of the outer ring 2. A hardened layer having a surface hardness in the range of 58 to 64 HRC is formed on the inner side outer raceway surface 2c and the outer side outer raceway surface 2d, for example, by high-frequency quenching. A vehicle body mounting flange 2e for attaching to a vehicle body side member (knuckle) (not shown) is integrally formed on the outer peripheral surface of the outer ring 2. A plurality of bolt holes 2f (see FIGS. 2 and 3) are formed in the axial direction in the vehicle body mounting flange 2e.

[0020] The hub ring 3 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C. A small-diameter stepped portion 3a having a reduced diameter on the outer peripheral surface is formed at the inner side end of the hub ring 3 compared to the outer side end. A wheel mounting flange 3b for mounting the wheel is integrally formed at the outer side end of the hub ring 3. A plurality of hub bolts 3e are provided at circumferentially equidistant positions on the wheel mounting flange 3b. Further, an inner raceway surface 3c on the outer side is provided on the hub ring 3 so as to face the outer raceway surface 2d on the outer side of the outer ring 2. Further, a lip sliding surface 3d of the outer seal member 10 is formed on the hub ring 3 on the base side of the wheel mounting flange 3b. An inner ring 4 is provided on the small-diameter stepped portion 3a of the hub ring 3.

[0021] The inner ring 4 applies preload to the inner ball row 5 arranged on the vehicle body side and the outer ball row 6 arranged on the wheel side during vehicle loading, which are rolling rows. An annular inner raceway surface 4a is formed in the circumferential direction on the outer peripheral surface of the inner ring 4. The inner ring 4 is fixed to the small-diameter stepped portion 3a of the hub ring 3 by press-fitting and caulking. That is, the inner raceway surface 4a is formed by the inner ring 4 on the inner side of the hub ring 3. The inner raceway surface 4a of the inner ring 4 faces the outer raceway surface 2c on the inner side of the outer ring 2.

[0022] The inner ball row 5 and the outer ball row 6, which are rolling rows, have a plurality of balls 8 as rolling elements annularly held by a cage 7. The inner ball row 5 is rotatably sandwiched between the inner raceway surface 4a of the inner ring 4 and the outer raceway surface 2c on the inner side of the outer ring 2. The outer ball row 6 is rotatably sandwiched between the inner raceway surface 3c of the hub ring 3 and the outer raceway surface 2d on the outer side of the outer ring 2.

[0023] The wheel bearing device 1 is composed of a double-row angular contact ball bearing including an outer ring 2, a hub ring 3 and an inner ring 4, an inner ball row 5, and an outer ball row 6. In this embodiment, the wheel bearing device 1 may be composed of a double-row tapered roller bearing.

[0024] The inner seal member 9, which is a sealing member, is a packing seal that closes the gap between the inner opening 2a of the outer ring 2 and the inner ring 4. The inner seal member 9 is composed of, for example, a two-side lip type encoder-equipped packing seal that brings two seal lips into contact.

[0025] The outer seal member 10, which is a sealing member, is mainly a seal member that closes the gap between the outer ring 2 and the hub ring 3. The outer seal member 10 is configured such that a cylindrical portion is fitted into the outer opening 2b of the outer ring 2, and a plurality of seal lips are in contact with or close to the lip sliding surface 3d of the hub ring 3 via an oil film, enabling sliding with respect to the hub ring 3.

[0026] As shown in Fig. 2(A), the outer raceway surface 2c on the inner side of the outer ring 2 is formed in a shape such that in the posture where the outer ring 2 is attached to the vehicle body, the direction perpendicular to the direction in which the gravity G acts (see the black arrow) is the large-diameter portion of diameter A, and the direction in which the gravity G acts is the small-diameter portion of diameter B. That is, on the outer raceway surface 2c on the inner side, a large-diameter portion and a small-diameter portion are formed at predetermined positions with respect to the vehicle body attachment flange 2e. Further, the outer raceway surface 2c on the inner side is not a simple elliptical shape where the large-diameter portion is offset to one side from the center of the small-diameter portion, but is formed in a substantially teardrop shape in a state corresponding to the elastic deformation during load application. Similarly, on the outer raceway surface 2d on the outer side of the outer ring 2, a large-diameter portion and a small-diameter portion are formed at predetermined positions with respect to the vehicle body attachment flange 2e.

[0027] As shown in Fig. 2(B), the large-diameter portion of diameter A of the outer raceway surface 2c on the inner side and the outer raceway surface 2d on the outer side is larger than the diameter of the reference true circle S1, and the small-diameter portion of diameter B is smaller than the diameter of the reference true circle S1. The outer raceway surface 2c on the inner side and the outer raceway surface 2d on the outer side having such a shape elastically deform such that the small-diameter portion increases in the direction of the gravity G and the large-diameter portion decreases in the direction perpendicular to the direction of the gravity G due to the vehicle's own weight and the like applied to the wheel bearing device 1 when the vehicle is stopped or moving forward. As a result, the outer raceway surface 2c on the inner side and the outer raceway surface 2d on the outer side approach the reference true circle S1 (the roundness decreases).

[0028] The specific shapes of the inner outer raceway surface 2c and the outer outer raceway surface 2d are calculated based on the analysis results of FEM analysis (finite element method analysis) using the three-dimensional model of the wheel bearing device 1. The FEM analysis of the wheel bearing device 1 restrains the bolt holes 2f of the vehicle body mounting flange 2e, and calculates the elastic deformation amount of the outer ring 2 when a load corresponding to the weight of the vehicle and a load corresponding to the reaction force from the wheel are applied to the inner outer raceway surface 2c and the outer outer raceway surface 2d of the outer ring 2. The inner outer raceway surface 2c and the outer outer raceway surface 2d are formed into a shape in which the roundness becomes equal to or less than a predetermined value when the same elastic deformation as the analysis result occurs in the outer ring 2.

[0029] As shown in FIG. 3(A), in the manufacturing method of the wheel bearing device 1, when grinding the inner outer raceway surface 2c and the outer outer raceway surface 2d, the inner outer raceway surface 2c and the outer outer raceway surface 2d are ground with an external force applied so that the elastic deformation of the analysis result occurs in the outer ring 2. During the grinding process, an inner side restraining jig 13 is fitted to the outer peripheral surface of the outer ring 2 at a position overlapping the touch diameter or the groove bottom diameter of the inner outer raceway surface 2c in the radial direction view, and an outer side restraining jig 14 is fitted to the outer outer raceway surface 2d at a position overlapping in the radial direction view.

[0030] As shown in FIGS. 3(B) and 4, the inner side restraining jig 13 is formed of an annular ring having an inner diameter that can be fitted to the outer peripheral surface at a position overlapping in the circumferential direction with the touch diameter or the groove bottom diameter of the inner outer raceway surface 2c of the outer ring 2, and a part thereof is cut and opened. That is, the inner side restraining jig 13 is formed in a horseshoe shape when viewed from the axial direction. The inner side restraining jig 13 also has fastening means for reducing the inner diameter by bringing one side end portion 13a and the other side end portion 13b of the cut portion closer to each other. The fastening means makes the one side end portion 13a and the other side end portion 13b in close contact by screwing in the screw 13c.

[0031] The inner peripheral surface 13d of the inner-side restraint jig 13 is formed into a shape that coincides with the shape of the outer peripheral surface at a position overlapping in the circumferential direction with the touch diameter or groove bottom diameter of the outer-side outer raceway surface 2c in the analysis result of the outer ring 2 by bringing the one-side end portion 13a and the other-side end portion 13b into close contact with each other. That is, the inner peripheral surface 13d of the inner-side restraint jig 13 is formed to have a large-diameter portion with a diameter C larger than the diameter of the reference perfect circle S2 and a small-diameter portion with a diameter D smaller than the diameter of the reference perfect circle S2. Similarly, the inner peripheral surface of the outer-side restraint jig 14 is formed into a shape that coincides with the shape of the outer peripheral surface at a position overlapping in the circumferential direction with the touch diameter or groove bottom diameter of the outer-side outer raceway surface 2d in the analysis result of the outer ring 2 by bringing the one-side end portion 14a and the other-side end portion 14b of the restraint jig into close contact with each other (see Fig. 3(A)).

[0032] As shown in Fig. 3(B), the inner-side restraint jig 13 (shaded portion) fitted at a position overlapping in the radial direction with the outer-side outer raceway surface 2c on the outer peripheral surface of the outer ring 2 has the one-side end portion 13a and the other-side end portion 13b brought into close contact with each other by a screw 13c which is a fastening means. That is, the inner-side restraint jig 13 is clamping the vicinity of the outer-side outer raceway surface 2c on the inner side with a predetermined force by the fastening force of the screw 13c (see the white-painted arrow). The inner side of the outer peripheral surface of the outer ring 2 is elastically deformed into the shape of the outer peripheral surface at a position overlapping in the circumferential direction with the touch diameter or groove bottom diameter of the outer-side outer raceway surface 2c in the analysis result by being pressed against the inner peripheral surface 13d of the inner-side restraint jig 13 over the entire circumference. Similarly, the outer side of the outer peripheral surface of the outer ring 2 is elastically deformed into the shape of the outer peripheral surface at a position overlapping in the circumferential direction with the touch diameter or groove bottom diameter of the outer-side outer raceway surface 2d in the analysis result by being pressed against the inner peripheral surface 14d (see Fig. 3(A)) of the outer-side restraint jig 14 over the entire circumference. Thereby, the elastic deformation shape of the outer ring 2 when the vehicle is stopped or moving straight while the wheel bearing device 1 is attached to the vehicle body is reproduced. That is, with the restraint jigs 13, 14 tightened, the shapes of the inner peripheral surfaces of the restraint jigs 13, 14 are precisely machined so that the fitting tightening allowance between the inner and outer sides of the outer peripheral surface of the outer ring 2 is appropriately changed in the circumferential direction.

[0033] The outer ring 2 is ground to a predetermined roundness for the inner outer raceway surface 2c and the outer outer raceway surface 2d on the inner side and the outer side in a state of being elastically deformed by the restraining jigs 13 and 14. That is, the inner outer raceway surface 2c and the outer outer raceway surface 2d are processed into a shape with a predetermined roundness by the elastic deformation of the outer ring 2 into the shape during grinding. In this way, by simply fitting the inner restraining jig 13 and the outer restraining jig 14 to the outer ring 2, the inner outer raceway surface 2c and the outer outer raceway surface 2d are processed into a complex shape corresponding to the elastic deformation during use.

[0034] In the wheel bearing device 1 configured in this way, since the vehicle weight is applied in the direction in which the gravity G (see Fig. 2(A)) is applied when the vehicle is stopped or moving straight, which is the time ratio of the load state is the most, the small diameter portions of the inner outer raceway surface 2c and the outer outer raceway surface 2d of the outer ring 2 are deformed to become larger. That is, for the inner outer raceway surface 2c and the outer outer raceway surface 2d of the outer ring 2, the difference between the large diameter portion of diameter A and the small diameter portion of diameter B is reduced by the vehicle weight, and the roundness of the raceway surface is maintained in an appropriate state. This is because in the manufacturing method of the wheel bearing device 1, the outer ring 2 is elastically deformed into the shape when the vehicle is stopped or moving straight for the entire circumference of the outer peripheral surface by fitting with the inner restraining jig 13 and the outer restraining jig 14, and the raceway surface is machined with high precision so as to fall within the desired roundness. Therefore, when the vehicle weight or the like is applied, the roundness of the inner outer raceway surface 2c and the outer outer raceway surface 2d of the outer ring 2 becomes smaller. As a result, the wheel bearing device 1 can suppress the rotational vibration during straight running and improve the bearing life while preventing the deterioration of the roundness of the outer raceway surfaces 2c and 2d without increasing the weight by increasing the rigidity of the outer ring 2, that is, increasing the wall thickness. Further, in this embodiment, since the deterioration of the roundness of any of the two rows of outer raceway surfaces 2c and 2d is prevented, the rotational vibration during high-speed straight running can be suppressed.

[0035] In addition, in this embodiment, although the wheel bearing device 1 has been described as a wheel bearing device for a driven wheel, it may be a wheel bearing device for a driving wheel in which a spline groove or the like is formed in the hub ring 3 and the drive shaft of the vehicle is fitted. Further, the outer ring 2 is ground with the inner side restraint jig 13 and the outer side restraint jig 14 fitted thereto, but it may be ground with either the inner side restraint jig 13 or the outer side restraint jig 14 fitted thereto. The inner side restraint jig 13 and the outer side restraint jig 14 can further improve the accuracy by performing a FEM analysis on the state of being fitted to the outer ring 2 and feeding back the result.

[0036] Next, with reference to FIGS. 5 and 6, a wheel bearing device 11 which is a second embodiment of the wheel bearing device according to the present invention will be described. Note that the wheel bearing device 11 according to each of the following embodiments is applied in place of the wheel bearing device 1 shown in FIG. 1, and by using the names, figure numbers, and reference signs used in the description thereof, the same thing is referred to. In the following embodiments, the specific description of the same points as those in the already described embodiments will be omitted, and the description will be centered on the different parts.

[0037] As shown in FIG. 5, the wheel bearing device 11 includes an outer ring 2 which is an outer member, a pair of inner rings 12 which are inner members, two rows of inner side ball rows 5 which are rolling element rows, an outer side ball row 6, and an inner side seal member 9. The wheel bearing device 11 is a wheel bearing device of an outer ring rotation type in which the outer ring 2 which is an outer member is a rotating wheel and a pair of inner rings 12 which are inner members are stationary wheels.

[0038] A wheel mounting flange 2g for mounting a wheel is integrally formed at the outer side end of the outer ring 2. A plurality of hub bolts 2h are provided at circumferentially equally spaced positions on the wheel mounting flange 2g. An inner side outer raceway surface 2c and an outer side outer raceway surface 2d which are formed in an annular shape are formed on the inner peripheral surface of the outer ring 2.

[0039] The pair of inner rings 12 apply preload to an inner-side ball row 5 arranged on the vehicle body side and an outer-side ball row 6 arranged on the wheel side during vehicle mounting, which are rolling rows. The pair of inner rings 12 are composed of an inner-side inner ring 12a and an outer-side inner ring 12b. On the outer peripheral surface of the inner-side inner ring 12a, an annular inner raceway surface 12c and a circumferential reference point 12d are formed in the circumferential direction for phase alignment during assembly to the vehicle. (Here, the reference point 12d is represented by a dimple-like small recess, but any shape or mark that can identify and distinguish the circumferential position, such as a notch shape, a surface-machined shape, or a marking by paint or laser, is acceptable.) On the outer peripheral surface of the outer-side inner ring 12b, an annular inner raceway surface 12e and a circumferential reference point 12f are formed in the circumferential direction. Also, the pair of inner rings 12 are fixed to a mounting shaft of a vehicle (not shown) by press fitting and axial restraint. The inner raceway surface 12c of the inner-side inner ring 12a faces the outer raceway surface 2c on the inner side of the outer ring 2. The inner raceway surface 12e of the outer-side inner ring 12b faces the outer raceway surface 2d on the outer side of the outer ring 2.

[0040] As shown in FIG. 6, the inner raceway surface 12c of the inner-side inner ring 12a has a large-diameter portion with a diameter E larger than the diameter of the reference perfect circle S3 and a small-diameter portion with a diameter F smaller than the diameter of the reference perfect circle S3. On the inner raceway surface 12c of the inner-side inner ring 12a, in the posture attached to the mounting shaft of the vehicle body, the large-diameter portion is in the direction perpendicular to the direction (refer to the black arrow) in which the gravity G is applied, and the direction in which the gravity G is applied is the small-diameter portion. That is, on the inner raceway surface 12c of the inner-side inner ring 12a, a large-diameter portion and a small-diameter portion are formed at predetermined positions with respect to the reference point 12d in the circumferential direction. Further, the inner raceway surface 12c of the inner-side inner ring 12a is not a simple elliptical shape in which the large-diameter portion is offset to one side from the center of the small-diameter portion, but is formed in a substantially teardrop shape in a state corresponding to the elastic deformation during load application. Similarly, on the inner raceway surface 12e of the outer-side inner ring 12b, a large-diameter portion and a small-diameter portion are formed at predetermined positions with respect to the reference point in the circumferential direction (refer to FIG. 5). The inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b having such a shape approach the reference perfect circle (the roundness becomes smaller) as the small-diameter portion becomes larger due to the elastic deformation caused by the load such as the vehicle's own weight applied to the wheel bearing device 11 when the vehicle stops or moves forward.

[0041] The specific shapes of the inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b are calculated based on the analysis results of FEM analysis (finite element method analysis) using the three-dimensional model of the wheel bearing device 11. In the FEM analysis of the wheel bearing device 11, the wheel mounting flange 2g of the outer ring 2 is constrained, and the elastic deformation amount of the pair of inner rings 12 when a load corresponding to the vehicle weight is applied to the mounting shaft of the vehicle is calculated. The inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b are formed in a shape such that the roundness becomes equal to or less than a predetermined value when the same elastic deformation as the analysis results occurs in the pair of inner rings 12.

[0042] As shown in Fig. 7(A), in the manufacturing method of the wheel bearing device 11, when grinding the inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b, the grinding of the inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b is performed while applying an external force to the pair of inner rings 12 so that elastic deformation of the analysis result occurs. During the grinding process, a restraining jig 15 is fitted to the pair of inner rings 12 at positions that overlap in the radial direction view on the inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b.

[0043] The restraining jig 15 is composed of a shaft-shaped member with an outer diameter that can be press-fitted into the inner peripheral surface at a position that overlaps in the circumferential direction with the touch diameter or groove bottom diameter of the inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b. The outer peripheral surface 15a of the restraining jig 15 is formed in a shape that coincides with the shape of the inner peripheral surface at a position that overlaps in the circumferential direction with the touch diameter or groove bottom diameter of the inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b in the analysis result of the inner ring.

[0044] In FIG. 7(B), a restraining jig 15 fitted at a position overlapping in the radial direction view on the inner raceway surface 12c of the inner-side inner ring 12a expands the vicinity of the inner raceway surface 12c of the inner-side inner ring 12a radially outward (see the white-painted arrow). The inner raceway surface 12c of the inner-side inner ring 12a is elastically deformed into the shape of the inner peripheral surface at a position overlapping in the circumferential direction with the touch diameter or groove bottom diameter of the inner raceway surface 12c of the inner-side inner ring 12a in the analysis result by being pressed against the outer peripheral surface 15a of the restraining jig 15 over the entire circumference. Similarly, the inner raceway surface 12e of the outer-side inner ring 12b is elastically deformed into the shape of the inner peripheral surface at a position overlapping in the circumferential direction with the touch diameter or groove bottom diameter of the inner raceway surface 12c of the inner-side inner ring 12a in the analysis result. Thereby, the elastic deformation shape when the vehicle is stopped or moving straight with the wheel bearing device 11 attached to the vehicle body is reproduced for the pair of inner rings 12. That is, in a state where the restraining jig 15 is press-fitted, the shape of the outer peripheral surface 15a of the restraining jig 15 is precisely machined so that the fitting allowance with the inner peripheral surfaces of the inner-side inner ring 12a and the outer-side inner ring 12b is appropriately changed in the circumferential direction.

[0045] The pair of inner rings 12 are elastically deformed by the restraining jig 15, and the inner raceway surfaces 12c and 12e are ground to a predetermined roundness. That is, the inner raceway surfaces 12c and 12e are processed into a shape having a predetermined roundness by elastically deforming the inner ring 2 into the shape during grinding.

[0046] In addition, in this embodiment, the inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b are ground with the restraint jig 15 fitted. However, grinding may be performed with the restraint jig 15 fitted at a position overlapping either one of the inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b. Further, the restraint jig 15 may be a vehicle mounting shaft having an outer peripheral surface formed in a shape that matches the shape of the inner peripheral surface at a position overlapping in the circumferential direction with the touch diameter or groove bottom diameter between the inner raceway surface 12c of the inner-side inner ring 12a and the inner raceway surface 12e of the outer-side inner ring 12b in the analysis result of the inner ring. The restraint jig 15 can further improve the accuracy by performing FEM analysis on the state of being fitted to the inner-side inner ring 12a and the outer-side inner ring 12b and feeding back the result.

[0047] The wheel bearing devices 1 and 11 in the present application may have a first-generation structure composed of an outer ring and a pair of inner rings. Alternatively, as long as it is limited to the wheel bearing device 1 of the inner ring rotation type, it may have a second-generation structure of an inner ring rotation specification in which a pair of inner rings are fitted to the outer periphery of a hub ring.

[0048] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to such embodiments at all, and is merely illustrative. Of course, the present invention can be implemented in various other forms without departing from the gist of the present invention. The scope of the present invention is indicated by the description in the claims, and further includes the equivalent meaning described in the claims and all modifications within the scope.

Description of Reference Numerals

[0049] 1 Wheel bearing device 2 Outer ring 2c Inner-side outer raceway surface 2d Outer-side outer raceway surface 4a Inner-side inner raceway surface 3c Outer-side inner raceway surface 3 Hub ring 4 Inner ring 5 Inner-side ball row 6 Outer ball row G Gravity

Claims

1. A stationary ring having a multi-row stationary-side raceway surface, A rotating ring having a multi-row rotating-side raceway surface facing the multi-row stationary-side raceway surface, A wheel bearing device having a multi-row of rolling elements rollably accommodated between both raceway surfaces of the stationary ring and the rotating ring, At least one of the multi-row stationary-side raceway surfaces is in a teardrop shape in which the diameter in the direction perpendicular to the direction in which gravity acts is larger than the diameter in the direction in which gravity acts in the posture attached to the vehicle body, The teardrop shape is In a state where the stationary ring is restrained, When a downward load corresponding to the weight of the vehicle body and an upward load corresponding to the reaction force received by the rotating ring from the ground are applied to the inner stationary-side raceway surface and the outer stationary-side raceway surface of the stationary ring, the elastic deformation occurring in the stationary ring is analyzed by FEM analysis, The inner stationary-side raceway surface and the outer stationary-side raceway surface are in a shape in which the roundness becomes equal to or less than a predetermined value when the same elastic deformation as the analysis result occurs in the stationary ring. A wheel bearing device.

2. The stationary-side raceway surface is a shape in which the roundness becomes smaller than the state before being attached to the vehicle body due to elastic deformation caused by the own weight of the vehicle when the vehicle is stopped or moving straight. The wheel bearing device according to claim 1.

3. A stationary ring having a multi-row stationary-side raceway surface, A rotating ring having a multi-row rotating-side raceway surface facing the multi-row stationary-side raceway surface, A multi-row of rolling elements rollably accommodated between both raceway surfaces of the stationary ring and the rotating ring, and having A method for manufacturing a wheel bearing device, wherein at least one of the multi-row stationary-side raceway surfaces is in a teardrop shape in which the diameter in the direction perpendicular to the direction in which gravity acts is larger than the diameter in the direction in which gravity acts in the posture attached to the vehicle body, The teardrop shape is In a state where the stationary ring is restrained, When a downward load corresponding to the weight of the vehicle body and an upward load corresponding to the reaction force received by the rotating ring from the ground are applied to the inner stationary-side raceway surface and the outer stationary-side raceway surface of the stationary ring, the elastic deformation occurring in the stationary ring is analyzed by FEM analysis, The inner stationary-side raceway surface and the outer stationary-side raceway surface are in a shape in which the roundness becomes equal to or less than a predetermined value when the same elastic deformation as the analysis result occurs in the stationary ring. A method for manufacturing a wheel bearing device, comprising fitting a restraint jig at a position that overlaps in a radial view on at least one of the stationary-side raceway surfaces, and machining the stationary-side raceway surfaces in a state where the stationary ring is elastically deformed so as to have the analyzed shape.

4. The restraint jig is formed of an annular member, provided with fastening means for opening at least one location and bringing its ends close to each other, and has an inner peripheral surface shaped to elastically deform the stationary-side raceway surface into the analyzed shape with the ends in close contact with each other. The method for manufacturing a wheel bearing device according to claim 3, wherein the outer peripheral surface of the stationary ring is pressed by the inner peripheral surface of the restraint jig by bringing the ends close to each other by the fastening means to elastically deform the stationary ring.

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