Wheel bearing device, and its manufacturing method

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. 8 has been proposed (for example, Patent Document 1). In this method, ball-shaped rolling elements 25 are interposed in multiple rows between the raceway surfaces 23 and 24 of the outer member 21 and the inner member 22 facing each other, and the inner member 22 is placed on the outer circumference of the wheel mounting hub flange 29a. It is of the type composed of the hub wheel 29 provided in the above and the inner ring 30 fitted to the outer circumference of the inboard side end of the hub wheel 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 29 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.

As shown in FIG. 9 which shows a part of FIG. 8 in an enlarged manner, in this proposed example, the inner ring 30 is externally fitted to the step portion 35 formed on the outer periphery of the inboard side end portion of the hub ring 29, and the inner ring 30 is fitted. A step portion 36 is formed on the inner circumference of the inboard side end portion, the inboard side end of the hub ring 29 is expanded and deformed to the outer diameter side by rocking compression, and the plastically deformed portion 29b is deformed to the outer diameter side of the inner ring 30. It is crimped to the step portion 36. This prevents the inner ring 30 from coming off due to an external force generated during assembly to the vehicle.

Further, as a wheel bearing device in which the inner ring is prevented from coming off, the inner ring 40 is pressed against the abutting surface 41a of the hub wheel 41 as shown in FIG. While restrained in the direction, insert the cold forming tool (punch) 42, and as shown in FIG. 11, cross-section S the inboard side end 41b of the hub wheel 41 until the step portion 40a of the inner ring 40 is satisfied. Patent Document 2 describes a product that has been plastically processed into a character shape.

<patcit num="1"><text>Japanese Unexamined Patent Publication No. 9-164803</text></patcit><patcit num="2"><text>U.S. Pat. No. 6,485,187</text></patcit>

<p> The wheel bearing device described in Patent Document 1 has the following problems. (1) Since the plastically deformed portion 29b of the hub ring 29 is large, it is necessary to make a large radial step (for example, about 5 to 7 mm in radius difference) of the step portion 36 formed at the inboard side end of the inner ring 30. When the step of the step portion 36 is increased, the area of the inboard side end surface 30a of the inner ring 30 becomes smaller, so that the contact surface pressure of the constant velocity joint outer ring 33 with the cross section 33b becomes larger. Therefore, it causes wear and abnormal noise. (2) When trying to fit the plastically deformed portion 29b of the hub ring 29 inside the inner ring 30 from the inboard side end (outboard side), the axial length of the step portion 36 of the inner ring 30 becomes longer (for example, 7 to 8 mm). Degree) need to be done. When the axial length of the inner ring step portion 36 becomes long in this way, the inner ring step portion 36 tends to be located on the extension line of the rolling element contact angle, and the inner ring deformation due to the load during operation becomes large, resulting in a short life. There is a possibility of becoming. Further, as the axial length of the inner ring step portion 36 becomes longer, the fitting length (area) of the inner ring 30 with respect to the hub wheel 29 decreases accordingly, so that inner ring creep may occur and the bearing life may be shortened. .. These problems can be avoided by increasing the width dimension of the entire inner ring, but this requires extra space in the width direction. (3) Further, since the plastically deformed portion 29b of the hub ring 29 is large, the crimping punch 19 interferes with the inner ring 30 in the swing crimping pressurization, which makes processing difficult.</p><p> Further, in the case of the wheel bearing device described in Patent Document 2, since the stepped portion 40a of the inner ring 40 is completely satisfied with the crimping to form an S-shape in the stepped portion 40a, the diameter of the inner ring 40 by the crimping is formed. The expansion becomes large, which causes the inner ring to crack. In particular, in order to plastically process the shaft end until the step portion 40a is satisfied, a very large processing load is required, and inner ring cracking may occur even during processing.</p><p> As a solution to such a problem, as shown in FIG. 12, an attempt was made to make the stepped portion 36 of the inner ring 30 shallow so as to have a depth corresponding to the inner peripheral edge of the inner ring end surface 30a. Even if the stepped portion 36 is made such a shallow one, a sufficient yield strength against the pulling force acting when the bearing is assembled to the vehicle can be obtained.</p><p> With the plastically deformed portion 29b with respect to such a small step portion 36, when performing the crimping process, the crimping process can be performed without using rocking crimping. For example, as shown in FIG. 13, the bearing device is fixed in a posture in which the inboard side faces upward, and in that state, the crimping punch 19 is lowered onto the inboard side end of the hub wheel 29 to lower the hub wheel 29. The method of pressing the plastically deformed portion 29b over the entire circumference can be taken. The load of the plastically deformed portion 29b is controlled as follows. That is, the shaft diameter of the hub wheel 29, the wall thickness of the inboard side end of the hub wheel 29, and the axial length are obtained in order to obtain the expanded deformation and the protrusion height of the inboard side end of the hub wheel 29. , The pressurizing load of the crimping punch 19 is determined in consideration of factors such as the shape of the inner ring step portion 36.</p><p> However, when pressing is performed with a predetermined pressure load, factors such as the hardness of the base metal, the heat treatment range, the dimensions of the plastically deformed part, and other factors that cause variations in machining accuracy depending on the workpiece, and the crimping that affects the punch insertion load. There is a problem that it is not possible to cope with the state of the punch (deterioration of the surface, the state of the adhering oil, etc.), and it is difficult to always obtain a stable crimping shape.</p><p> An object of the present invention is to provide a wheel bearing device capable of preventing the inner ring from coming off in the assembly process of a vehicle without adversely affecting the bearing function, and to manufacture the wheel bearing device with high accuracy and stability at all times. Is to provide a manufacturing method that can be used.</p>

<p> The wheel bearing device of the present invention comprises an outer member having a double row of raceway surfaces on the inner circumference, an inner member having a raceway surface facing the raceway surface, and a double row interposed between the raceway surfaces facing each other. A hub wheel provided with a rolling element, the inner member having a hub flange for mounting an axle on the outer periphery and a through hole in the center, and an inner ring fitted on the outer periphery of the inboard side end of the hub wheel. Therefore, it is for supporting the drive wheels in which the raceway surfaces of the respective rows are formed on the hub wheels and the inner rings. In this wheel bearing device, a step portion having a depth corresponding to the inner peripheral edge of the end surface is provided on the inner peripheral surface of the inner ring, extending to the end surface on the inboard side of the inner ring, and the inner surface of the step portion is formed into a cylinder. The shape is formed by a straight portion formed of a surface and a tapered surface extending from the end portion of the straight portion to the inner peripheral surface of the inner ring, and is engaged with the tapered surface of the stepped portion of the inner ring by crimping the hub wheel. A plastic deformed portion is provided so that the plastic deformed portion does not protrude from the end surface of the inner ring and does not come into contact with the straight portion of the stepped portion, and the outer peripheral surface of the tip of the plastic deformed portion is tapered. It is characterized in that the crimping punch is pushed into the inner circumference of the inboard side end of the hub wheel to crimp to the enlarged diameter state.</p><p> In the wheel bearing device of the present invention, the inboard side end portion of the hub wheel is enlarged by plastic deformation by crimping, and this plastic deformation portion is engaged with the tapered surface of the inner ring step portion to prevent the inner ring from coming off. It is a structure to regulate. In this configuration, since the inner ring stepped portion is within a very limited range of the inner peripheral edge of the inner ring, the stepped portion can be made as small as possible while ensuring the pull-out resistance of the inner ring. Therefore, it is possible to reduce the decrease in the area of the inner ring end surface while providing the stepped portion, suppress the increase in the contact surface pressure of the constant velocity joint outer ring with the step surface, and prevent the generation of wear and abnormal noise. Even if the stepped portion on the inner peripheral surface of the inner ring is made small as described above, sufficient proof stress can be obtained against the pulling force acting when the bearing is assembled to the vehicle. In this way, by setting the stepped portion of the inner ring as small as possible within the range in which the yield strength of the inner ring can be secured, it is possible to prevent the inner ring from coming off in the assembly process of the vehicle without adversely affecting the bearing function.</p><p> When the plastically deformed portion of the hub wheel is crimped, this plastically deformed portion does not come into contact with the inner diameter straight portion of the inner ring step portion, so that no extra load is applied to each hub wheel portion and each inner ring portion other than the plastic deformed portion. , Deformation of the part where the stem portion of the constant velocity joint on the hub shaft is fitted and expansion of the inner ring can be suppressed to a small extent. As a result, it is possible to avoid adversely affecting the bearing function. During this crimping process, the plastically deformed portion of the hub ring can be easily plastically deformed along the tapered surface of the inner ring stepped portion. Therefore, appropriate crimping can be performed, and the pull-out proof stress can be further ensured. Further, the crimping process of the inboard side end of the hub wheel is performed by pushing a crimping punch having a tapered tip outer peripheral surface into the inner circumference of the inboard side end of the hub wheel. This processing can be easily performed without the crimping punch interfering with the inner ring during tightening and pressurization.</p><p> In the present invention, the through hole of the hub ring has a spline groove on the inner peripheral surface that meshes with a spline on the outer periphery of the stem portion of the constant velocity universal joint, and the spline groove is formed on the inner peripheral surface of the through hole. The portion on the inboard side of the general diameter portion is the large diameter step portion that is the inner peripheral surface of the plastic deformation portion and the intermediate diameter that is smaller than the large diameter step portion and larger than the general diameter portion. It is better to have a two-step stepped shape that forms a step. In this configuration, the inboard side end of the hub ring whose inner peripheral surface is the large-diameter stepped portion of the through hole is crimped as a plastically deformed portion to prevent the inner ring from coming off in the assembly process to the vehicle. The spline on the outer periphery of the stem portion of the constant velocity universal joint is meshed with the spline groove formed in the general diameter portion of the through hole, and the stem portion of the constant velocity universal joint is spline-fitted into the through hole. The plastically deformed portion is a portion of the hub ring having a large inner diameter and a thin wall thickness, and the overall volume is small. Therefore, the stepped portion of the inner ring can be made small and the crimping process is facilitated. .. In addition, since the through hole has a two-step stepped shape with an inner diameter larger toward the inboard side, the constant velocity can be freely adjusted when the stem portion of the constant velocity universal joint is spline-fitted to the general diameter portion of the through hole. The stem part of the joint can be easily inserted from the inboard side, and the assembly work is easy.</p><p> In the present invention, the raceway surface of the hub ring may be a hardened surface-hardened surface, the crimped portion may be a non-heat-treated portion, and the inner ring may be hardened entirely from the surface to the core portion by quenching. .. The raceway surface of the hub wheel is preferably hardened as a surface-hardened surface from the viewpoint of improving the rolling life, but the portion to be crimped is a non-heat-treated portion from the viewpoint of ease of crimping. It is preferable to do so. Since the inner ring is a small part and has a raceway surface and the inner diameter surface is fitted to the hub ring, it is necessary to harden the entire surface to the core by quenching to improve the rolling life and the rolling life. It is preferable in terms of improving the wear resistance of the mating surface.</p><p> The method for manufacturing a wheel bearing device of the present invention is applied to the wheel bearing device, and the plastically deformed portion has a cylindrical shape before deformation and a tapered tip outer peripheral surface. By pushing the crimping punch into the inner circumference of the inboard side end of the hub wheel in the axial direction, the crimping punch is crimped to the enlarged diameter state, and by adjusting the stroke in the axial direction in which the crimping punch is pushed, the plasticity after crimping is performed. It is characterized by adjusting the outer diameter of the deformed portion.</p><p> According to this manufacturing method, it is possible to adjust the stroke in the axial direction in which the crimping punch is pushed in according to the factors of variation in machining accuracy depending on the workpiece and the state of the crimping punch. Therefore, the press working can always be performed stably so that the plastically deformed portion expands in the radial direction and the protrusion height becomes constant, and the inner ring of the finished product can be prevented from coming off. This crimping process is performed by pushing a crimping punch having a tapered tip outer peripheral surface into the inner circumference of the inboard side end of the hub wheel in the axial direction. Does not interfere with the inner ring, and this processing can be easily performed.</p>

<p> The wheel bearing device of the present invention comprises an outer member having a double row of raceway surfaces on the inner circumference, an inner member having a raceway surface facing the raceway surface, and a double row interposed between the raceway surfaces facing each other. A hub wheel provided with a rolling element, the inner member having a hub flange for mounting an axle on the outer periphery and a through hole in the center, and an inner ring fitted on the outer periphery of the inboard side end of the hub wheel. In the wheel bearing device for supporting the drive wheels in which the raceway surfaces of the respective rows are formed on the hub wheels and the inner rings, the inner peripheral surface of the inner ring continues to the end surface on the inboard side of the inner ring, and the end surface of the inner ring. A stepped portion having a depth corresponding to the inner peripheral edge is provided, and the inner surface of the stepped portion has a shape consisting of a straight portion composed of a cylindrical surface and a tapered surface extending from the end portion of the straight portion to the inner peripheral surface of the inner ring. By crimping the hub wheel, a plastically deformed portion that engages with the tapered surface of the stepped portion of the inner ring is provided, and the plastically deformed portion does not protrude from the end surface of the inner ring and the straight portion of the stepped portion. Because the plastically deformed portion is crimped to an expanded state by pushing a crimping punch having a tapered tip outer peripheral surface into the inner circumference of the inboard side end of the hub wheel. , It is possible to prevent the inner ring from coming off in the assembly process of the vehicle without adversely affecting the bearing function.</p><p> Further, the manufacturing method of the wheel bearing device of the present invention is a manufacturing method applied to the axle bearing device, and the plastically deformed portion has a cylindrical shape before deformation and a tapered tip outer peripheral surface. After crimping, the crimping punch is pushed into the inner circumference of the inboard side end of the hub wheel in the axial direction to expand the diameter, and the stroke in the axial direction to push the crimping punch is adjusted. Since the outer diameter of the plastically deformed portion is adjusted, there is little variation in machining accuracy, and a wheel bearing device can always be manufactured accurately and stably.</p>

An embodiment of the present invention will be described with reference to FIGS. 1 to 3. 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 of the vehicle that is attached to the vehicle and is closer to the outside in the vehicle width direction 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 raceway surfaces 3 formed on the inner circumference, an inner member 2 having a raceway surface 4 facing each of these raceway surfaces 3, and these outer members 1. It is composed of a double-row ball-shaped rolling element 5 interposed between the raceway surfaces 3 and 4 of the inner member 2. This wheel bearing device is of a double-row outward-facing angular contact ball bearing type, and the rolling elements 5 are held by cages 6 in each row. The raceway surfaces 3 and 4 have an arcuate cross section, and the raceway surfaces 3 and 4 are formed so that the rolling element contact angles θ 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, and has a flange 1a on the outer circumference to be attached to a knuckle in a suspension device (not shown) of a vehicle body, and the whole is an integral part. The inner member 2 is a member on the rotation side, and has a hub ring 9 having a hub flange 9a for mounting wheels on the outer circumference and an inner ring 10 fitted on the outer circumference of the inboard side end of the hub ring 9. It consists of. A raceway surface 4 of each row is formed on the hub ring 9 and the inner ring 10. The hub ring 9 has a through hole 11 in the center, and the raceway surface 4 thereof is a surface hardened surface by quenching treatment. The entire inner ring 10 from the surface to the core is hardened by quenching.

The through hole 11 of the hub ring 9 has a general diameter portion 11a that occupies from the outboard side end to the vicinity of the inboard side end, and is on the inboard side of the general diameter portion 11a and has a larger diameter than the general diameter portion 11a. It has a two-step stepped shape consisting of a certain intermediate-diameter step portion 11b and a large-diameter step portion 11c that is further inboard side of the intermediate-diameter step portion 11b and has a larger diameter than the intermediate-diameter step portion 11b. There is. A spline groove 11d that meshes with a spline on the outer circumference of the stem portion 13a of the constant velocity universal joint 12 is formed on the inner peripheral surface of the general diameter portion 11a.

As shown in the enlarged cross-sectional view of FIG. 2, a stepped inner ring fitting surface portion 15 having a diameter smaller than the outer circumference of the other portion of the hub ring 9 is formed on the outer periphery of the inboard side end of the hub ring 9. Then, the inner ring 10 is fitted to the inner ring fitting surface portion 15. The inner peripheral surface of the inner ring 10 is provided with a stepped portion 16 having a depth corresponding to the inner peripheral edge of the end surface 10a, which continues to the end surface 10a on the inboard side of the inner ring 10. The inner surface of the stepped portion 16 is connected to the inner peripheral surface of the inner ring 10 on the outboard side, and the tapered surface 16a whose diameter increases in a tapered shape to the depth as it goes to the inboard side, and the inner ring following the tapered surface 16a. It is composed of a straight portion 16b formed of a cylindrical surface having the depth up to the inboard side end of 10. The axial range W of the step portion 16 is a range that does not extend on the extension line of the straight line L forming the rolling element contact angle θ of the inner ring raceway surface 4.

On the other hand, the inboard side end portion of the hub ring 9 is a plastically deformed portion 9b that is plastically deformed by crimping to increase the diameter. This plastically deformed portion 9b is a non-heat-treated portion so that crimping can be easily performed. The inner peripheral surface of the plastically deformed portion 9b is a large-diameter step portion 11c of the through hole 11. As shown in FIG. 3 (A), the plastically deformed portion 9b has a cylindrical shape before the crimping process, and as shown in FIG. 3 (B), the plastic deformed portion 9b is expanded and deformed after the crimping process. The expanded-diameter deformed plastic deformed portion 9b engages with the tapered surface 16a of the stepped portion 16 to restrict the movement of the inner ring 10 to the inboard side. Further, the plastically deformed portion 9b after the crimping process does not come into contact with the straight portion 16b of the stepped portion 16, and a gap E remains between the plastically deformed portion 9b and the stepped portion 16, and the inner ring 10 It is assumed that it does not protrude toward the inboard side from the end face 10a of. The inner diameter surface 9bc of the plastically deformed portion 9b after the crimping process is a tapered surface whose end side opens.

In assembling this wheel bearing device to a vehicle, the stem portion 13a of the outer ring 13 which is one of the joint members of the constant velocity joint 12 is inserted into the through hole 11 of the hub wheel 9 and spline-fitted to fit the stem. By tightening the nut 14 screwed to the tip of the portion 13a, the constant velocity joint outer ring 13 is connected to the inner member 2. At this time, the stepped surface 13b provided on the constant velocity joint outer ring 13 facing the outboard side is pressed against the end surface 10a facing the inboard side of the inner ring 10, and the inner member 2 is formed by the constant velocity joint outer ring 13 and the nut 14. Is tightened. The hub flange 9a for wheel mounting is located at the outboard side end of the hub wheel 9, and wheels (none of which are shown) are mounted on the hub flange 9a via a brake rotor with hub bolts 17.

According to the wheel bearing device having this configuration, a step portion 16 is provided on the inner peripheral surface of the inner ring 10, and the plastically deformed portion 9b due to the crimping process of the hub ring 9 is engaged with the step portion 16, so that the vehicle can be fitted. It is possible to prevent the inner ring 10 from coming off from the hub wheel 9 due to an external force generated in the assembly process. Since the step portion 16 has a very limited range of the inner peripheral edge of the inner ring 10, the step portion 16 can be made as small as possible while ensuring the pull-out resistance of the inner ring 10. Therefore, the area of the end surface 10a of the inner ring 10 is less reduced while the step portion 16 is provided, the increase in the contact surface pressure of the constant velocity joint outer ring 13 with the step surface 13b is suppressed, and the occurrence of wear and abnormal noise can be prevented. ..

Further, this wheel bearing device is a plurality of outward angular contact ball bearing type, and the axial range W of the step portion 16 is set so as not to be on the extension line of the straight line L forming the rolling element contact angle θ. The deformation of the inner ring 10 due to the load can be reduced, and the life can be extended accordingly. Further, since the axial length of the step portion 16 of the inner ring 10 is short, the fitting length of the inner ring 10 with respect to the hub wheel 9 can be secured, and therefore the fitting area can be secured, and the occurrence of creep of the inner ring 10 can be suppressed. Can be done. From this point as well, the life can be extended. Further, since it is not necessary to lengthen the entire width dimension of the inner ring 10 in order to secure the fitting length and the like, extra space is not required in the axial direction.

When the plastic deformed portion 9b of the hub ring 9 is crimped, this plastic deformed portion 9b does not come into contact with the inner diameter straight portion 16b of the inner ring step portion 16, so that each part of the hub ring 9 and each part of the inner ring 10 other than the plastic deformed portion 9b No extra load is applied, and the deformation of the through hole 11 of the hub ring 9 to which the stem portion 13a of the constant velocity joint 12 fits and the expansion of the inner ring 10 can be suppressed to a small extent. As a result, it is possible to avoid adversely affecting the bearing function. During this crimping process, the plastically deformed portion 9b of the hub ring 9 can be easily plastically deformed along the tapered surface 16a of the inner ring stepped portion 16. Therefore, appropriate crimping can be performed, and the pull-out proof stress can be further ensured.

The plastically deformed portion 9b having the large-diameter step portion 11c of the through hole 11 as the inner peripheral surface is a portion of the hub ring 9 having a large inner diameter and a thin wall thickness, and has a small overall volume, so that crimping is easy. .. Further, since the plastic deformed portion 9b is small, the protrusion height h does not become higher than necessary even when the diameter is increased, and even if the step of the inner ring step portion 16 is made small, the plastic deformed portion 9b is the inner ring step portion 16. It is possible not to touch the straight part 16b of. Further, since the through hole 11 has a two-step stepped shape having an inner diameter larger toward the inboard side, when the stem portion 13a of the constant velocity universal joint 12 is spline-fitted to the general diameter portion 11a of the through hole 11. In addition, the insertion is easy and the assembly work is easy.

Further, in this wheel bearing device, since the raceway surface 4 of the hub wheel 9 is a hardened surface-treated surface, the rolling life can be ensured. Since the plastically deformed portion 9b is a non-heat-treated portion, crimping can be easily performed. Since the inner ring 10 is a small part and has a raceway surface 4 and the inner diameter surface is fitted to the hub ring 9, the entire surface to the core portion is hardened by quenching as described above. The rolling life is excellent, and the wear resistance of the fitting surface is excellent.

Next, a method of crimping the plastically deformed portion 9b of the hub ring 9 to the inner ring stepped portion 16 will be described with reference to FIGS. 4 to 7. In this crimping process, first, as shown in FIG. 4, the hub flange 9a of the hub wheel 9 is attached to the pedestal 18 with the hub bolt 17, and the bearing device is fixed on the pedestal 18 in a posture in which the inboard side faces upward. In this fixed state, as shown in FIG. 5A, the crimping punch 19 having a tapered tip outer peripheral surface 19a is lowered onto the inboard side end of the hub wheel 9, and the tapered tip is formed. By pushing the portion into the inner circumference of the hub ring 9, the plastically deformed portion 9b of the hub ring 9 is pressed over the entire circumference. The inner ring 10 pushes the crimping punch 19 with the outer diameter surface unconstrained. At that time, the outer diameter of the plastically deformed portion 9b after crimping is adjusted by controlling the stroke in the axial direction in which the crimping punch 19 is pushed. There are three methods for stroke control.

FIG. 6A shows a method of controlling the stroke of the crimping punch 19 with the end face of the hub wheel 9 as the stroke reference (zero point) of the crimping punch 19. This method is suitable for controlling the degree of machining because the end face of the hub ring 9 which is the workpiece is used as the control reference plane. FIG. 6B shows a method of controlling the stroke of the crimping punch 19 with the end surface 10a of the inner ring 10 as the stroke reference (zero point) of the crimping punch 19. In this method, since the end surface 10a of the inner ring 10 which is the polished finished surface is used as the control reference surface, accurate control can be performed. In FIG. 6C, the stroke of the crimping punch 19 is set so that the crimping punch 19 is lowered by a certain stroke from the position where the crimping punch 19 contacts the hub wheel 9 as a stroke reference (zero point). The method of control is shown. In this method, since the starting point of plastic working is used as the control reference point, a stable working degree can be obtained without being affected by variations in tolerances such as the inner diameter of the hub ring 9 and the position of the end face. In either control method, the outer diameter of the plastically deformed portion 9b after crimping is adjusted by adjusting the stroke in the axial direction in which the crimping punch 19 is pushed, so that the machining is caused by the hub wheel 9 which is the workpiece. It is less affected by accuracy variation factors (base metal hardness, heat treatment range, shape and dimensions of plastically deformed part 9b, etc.) and the state of the crimping punch (surface deterioration, adhering oil state, etc.). A wheel bearing device can always be manufactured accurately and stably. As described above, each control method has slightly different advantages and suitability. Therefore, the most appropriate control method may be selected according to various conditions such as the form and application of the bearing.

By performing press working while adjusting the stroke of the crimping punch 19 by any of the above control methods, a hub wheel is shown by enlarging a part of FIG. 5 (A). The plastically deformed portion 9b of 9 is crimped to the inner ring step portion 16. Since the outer peripheral surface portion 19a of the tip of the crimping punch 19 is a tapered surface, the crimping process is smoothly performed. Further, the portion of the hub ring 9 that becomes the plastically deformed portion 9b has an inner diameter surface larger than that of the other portions before and after the crimping process, and the wall thickness is reduced. After crimping in this way, the crimping process is completed when the crimping punch 19 is retracted from the inboard side end of the hub wheel 9 as shown in FIG.

According to this manufacturing method, the axial stroke for pushing the crimping punch 19 can be adjusted according to the factors of variation in the machining accuracy due to the hub wheel 9 which is the workpiece and the state of the crimping punch 19. Therefore, the press working can always be performed stably so that the protrusion height h in the radial direction of the plastically deformed portion 9b is constant, and the inner ring of the finished product can be prevented from coming off. This crimping process is performed by pushing the crimping punch 19 having a tapered tip outer peripheral surface into the inner circumference of the inboard side end of the hub wheel 9 in the axial direction. This processing can be easily performed without the tightening punch 19 interfering with the inner ring 10.

<figref num="1">It is sectional drawing of the bearing device for a wheel which concerns on 1st Embodiment of this invention.</figref><figref num="2">It is a partially enlarged sectional view of the bearing device for the wheel.</figref><figref num="3">In the enlarged view of the hub ring plastically deformed portion, the inner ring step portion and the peripheral portion thereof, (A) shows the state before the crimping process, and (B) shows the state after the crimping process.</figref><figref num="4">It is explanatory drawing which shows the pre-process of the crimping process of the bearing device for a wheel.</figref><figref num="5">(A) is an explanatory view showing an intermediate process of the crimping process of the bearing device for the same wheel, and (B) is a partially enlarged view thereof.</figref><figref num="6">In the explanatory view showing the stroke control of the crimping punch in the crimping process of the bearing device for the same wheel, (A) to (C) show different control methods.</figref><figref num="7">It is explanatory drawing which shows the completion of the crimping process of the bearing device for a wheel.</figref><figref num="8">It is sectional drawing of the conventional example of the bearing device for a wheel.</figref><figref num="9">It is a partially enlarged sectional view of the same conventional example.</figref><figref num="10">It is sectional drawing of the conventional example different from the bearing device for a wheel.</figref><figref num="11">It is a partially enlarged sectional view of the same conventional example.</figref><figref num="12">It is a partially enlarged sectional view of the bearing device for a wheel which is an example of a tentative plan.</figref><figref num="13">It is explanatory drawing which shows the crimping process of the tentative plan example.</figref>

Code description

1 ... outer member 2 ... inner member 3 ... raceway surface of outer member 4 ... raceway surface of inner member 5 ... rolling element 9 ... hub wheel 9a ... Hub flange 9b ... Plastic deformation part 10 ... Inner ring 10b ... Inner ring end face 11 ... Through hole 11a ... General diameter part 11b ... Intermediate diameter step part 11c ... Large diameter step part 16 ... Inner ring stepped portion 16a ... Inner ring stepped portion tapered surface 16b ... Inner ring stepped portion straight portion 19 ... Clamping punch W ... Inner ring stepped portion axial range θ ... Roller contact angle L ... Straight line forming ball contact angle