JP2008101685A - Bearing device for wheel and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel and its manufacturing method achieving cost reduction by reducing the number of processing man-hours and material loss and elongating the service life of a bearing. <P>SOLUTION: An outer member 2 is forged from a round bar material leaving a predetermined turning allowance. In this forging process, groove parts 18 corresponding to double row outer rolling surfaces 2a are formed to have an arcuate cross section. In the tangential direction of the groove parts 18, counterbores 15, 16 are formed to have a tapered shape, and then, the double row outer rolling surfaces 2a are formed to have predetermined shape dimension by turning or grinding without processing part of the counterbores 15, 16. Thus, with respect to the tangential direction of the outer rolling surfaces 2a and balls 3, the arcuate faces of the groove parts 18 and the outer rolling surfaces 2a are formed concentrically. As a result, the cutting allowance becomes uniform, so as to suppress cutting processing amount and reduce the number of processing man-hours. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wheel bearing device for rotatably supporting a wheel of an automobile or the like, and more particularly to a wheel bearing device that achieves cost reduction by reducing processing man-hours and material loss, and extends the life of the bearing, and its It relates to a manufacturing method.

  2. Description of the Related Art Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like is such that a hub wheel for mounting a wheel is rotatably supported via a rolling bearing, and there are a drive wheel and a driven wheel. For structural reasons, an inner ring rotation method is generally used for driving wheels, and an inner ring rotation method and an outer ring rotation method are generally used for driven wheels. As the wheel bearing device, a double-row angular ball bearing having a desired bearing rigidity, exhibiting durability against misalignment, and having a small rotational torque from the viewpoint of improving fuel efficiency is often used. In this double row angular contact ball bearing, a plurality of balls are interposed between a fixed ring and a rotating ring, and a predetermined contact angle is given to the balls so as to contact the fixed ring and the rotating ring.

  Further, the wheel bearing device has a structure called a first generation in which a wheel bearing composed of a double row angular ball bearing or the like is fitted between a knuckle and a hub wheel constituting a suspension device. Second generation structure in which body mounting flange or wheel mounting flange is formed directly on the outer periphery of the member, third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub wheel, or hub wheel, etc. It is roughly classified into a fourth generation structure in which the inner rolling surface is directly formed on the outer periphery of the outer joint member of the speed universal joint. In the following description, the side closer to the outer side of the vehicle in a state assembled to the vehicle is referred to as the outer side (left side in the drawing), and the side closer to the center is referred to as the inner side (right side in the drawing).

  In a wheel bearing device composed of such double-row rolling bearings, it is a method of manufacturing an outer member by forging a round bar-shaped material. As shown in FIG. 6, it is known that durability is sufficiently ensured by preventing the occurrence of.

  The outer member 50 in this wheel bearing device integrally has a vehicle body mounting flange 50b to be attached to a knuckle (not shown) on the outer periphery, and a double row outer rolling surface 50a having an arc cross section on the inner periphery. , 50a are formed. This outer member 50 is a cut surface including a central axis, and a flow line located at the most central part of the substantially annual ring-shaped fiber flow in which a plurality of annular flow lines overlap from the center toward the outside, An inner portion (a portion indicated by a satin surface in the figure) whose outer edge is defined is interposed between the outer row rolling surfaces 50a, 50a of the double row separated from the outer row rolling surfaces 50a, 50a of the double row with respect to the axial direction. It is located.

  The outer member 50 is manufactured by a process as shown in FIG. First, as a first step, the carbon steel constituting the outer member 50 and a round bar-shaped material 51 having a long axial dimension are subjected to upsetting that is compressed in the axial direction while being heated (a). Then, by this upsetting process, the first intermediate material 52 having a short cylindrical shape with a short axial dimension and a large diameter is obtained (b). Next, as a second step, the first intermediate material 52 is forged to obtain a second intermediate material 53 having a rough shape of the outer member 50 and having a vehicle body mounting flange 50b (c). ). In the second step, recesses 53a and 53b are formed in the center portions of both end surfaces in the axial direction of the second intermediate material 53, respectively. Further, the disk portion 54 to be punched by a punching process in a later step is formed between the both concave portions 53a and 53b of the second intermediate material 53, and double row outer rolling surfaces 50a and 50a are formed in the axial direction. It is provided in the part between the power parts. Next, as a third step, the disk portion 54 provided in the intermediate portion of the second intermediate material 53 is deleted by punching to form the inner diameter portion 56, and the third intermediate material 55 is obtained. (D).

In the second step, the flow located at the center of the substantially annual ring-shaped fiber flow in which a plurality of rings overlap from the center toward the outside at the cut surface including the central axis of the third intermediate material 55. The inner portion defining the outer edge of the line (a portion in FIG. 6) is between the outer raceway surfaces 50a, 50a of these double rows separated from the outer row raceways 50a, 50a of the double rows in the axial direction. The forging process is given so that it may be located. As a result, non-metallic inclusions are less likely to be generated near the outer rolling surface 50a, and even when used under severe conditions, the occurrence of premature peeling at the outer rolling surfaces 50a, 50a of these double rows is prevented and durability is maintained. It is possible to ensure sufficient properties. Further, segregation can hardly occur in the vicinity of the double-row outer raceway surfaces 50a and 50a, so that the hardenability at the time of induction hardening can be improved.
JP 2005-180627 A

  In such a conventional outer member 50, as shown in FIG. 8, in the forging process, a forging shape in which a predetermined turning allowance is left in the portion to be turned, that is, the inner side surface 57 and the knuckle of the vehicle body mounting flange 50b. In addition to the outer diameter surface 58 and both end surfaces 59, 60 (not shown) to be fitted, double row outer rolling surfaces 50a, 50a and inner diameter from the seal fitting surfaces 61, 62 through the counter bores 63, 64. Over the surface 65, the outer member 50 (indicated by a two-dot chain line in the figure) is formed into a forged shape leaving a predetermined turning allowance.

  However, since the counter bores 63 and 64 of the double row outer rolling surfaces 50a and 50a are formed to protrude radially inward from the groove bottom and the seal fitting surfaces 61 and 62, the outer rolling surfaces having an arcuate cross section are formed. The part corresponding to the surface 50a must be forged with a turning allowance remaining unnecessarily. This not only increases the amount of turning of this part and increases the number of processing steps, but also increases the amount of forging material input and increases material loss, which may be an obstacle to reducing the cost of the product. there were.

  Further, when the portions corresponding to the double row outer rolling surfaces 50a, 50a are turned and ground after the heat treatment, the forging shape does not follow the shape of the double row outer rolling surfaces 50a, 50a. Therefore, it cannot be denied that the fiber flow F is divided and the division angle of the fiber flow F is increased. There is a correlation between the split angle of the fiber flow F and the rolling fatigue life, and it is known that the rolling fatigue life decreases as the angle increases. Therefore, in such a forging process of the outer member 50, it has been a problem how to reduce the number of processing steps and material loss of the material to reduce the cost and how to extend the life of the bearing.

  The present invention has been made in view of such circumstances, and provides a wheel bearing device and a method for manufacturing the same that reduce costs by reducing processing man-hours and material loss, and extend the life of the bearing. The purpose is that.

  In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member having a double-row outer rolling surface having an arcuate cross section on the inner periphery, and an outer roll of the double-row on the outer periphery. An inner member in which a double-row inner rolling surface having an arc-shaped cross section facing the running surface is formed, and a double row accommodated in a freely rolling manner between both rolling surfaces of the inner member and the outer member. A counter bore is formed at the end of the outer rolling surface of the double row, and the counter bore has a diameter slightly from the groove bottom of the outer rolling surface of the double row. It projects inward in the direction, and is formed in a tapered shape that gradually increases in diameter toward the end face of the outer member.

  Thus, in the wheel bearing device constituted by the double row angular contact ball bearing having the outer member having the double row outer raceway formed on the inner periphery, the counter is provided at the end of the double row outer raceway. Since the bore is formed, this counter bore protrudes slightly inward in the radial direction from the groove bottom of the double row outer rolling surface, and is formed in a tapered shape that gradually increases in diameter toward the end surface of the outer member. It is possible to provide a wheel bearing device that achieves cost reduction by reducing processing man-hours and material loss, and extends the life of the bearing.

  In addition, as in the invention described in claim 2, if a part of the counterbore is left as forged skin, the amount of turning can be reduced to reduce the processing man-hour, and the forging material can be reduced. Material loss can be reduced by minimizing the amount of input.

  According to a third aspect of the present invention, there is provided a method invention comprising: an outer member having a double-row outer rolling surface having an arc-shaped cross section on the inner circumference; and the outer rolling surface of the double row on the outer circumference. An inner member formed with a double-row inner rolling surface having an arc cross section facing the inner surface, and a double-row ball accommodated in a freely rollable manner between both rolling surfaces of the inner member and the outer member In the method for manufacturing a wheel bearing device, the outer member is formed by forging while leaving a predetermined turning allowance, and in this forging step, a groove corresponding to the outer rolling surface of the double row Is formed in an arc shape in cross section, and a counter bore is formed in a taper shape at the end of the groove, and thereafter, the outer rolling surface of the double row is turned and the part of the counter bore is not processed. It is formed in a predetermined shape and size by grinding.

  Thus, in the method for manufacturing a wheel bearing device including a double-row angular contact ball bearing having an outer member having a double-row outer raceway formed on the inner periphery, the outer member has a predetermined turning allowance. In this forging process, a groove corresponding to the double row outer rolling surface is formed in an arc shape in cross section, and a counter bore is formed in a tapered shape at the end of the groove. Then, since a part of the counterbore is not processed and the double row outer rolling surfaces are formed in a predetermined shape and size by turning and grinding, the processing man-hour can be reduced, Material loss can be reduced by minimizing the amount of forging material input.

  Preferably, as in the invention according to claim 4, if the counter bore is formed in the tangential direction of the groove portion, the fiber flow of the groove portion is formed substantially parallel along the outer rolling surface, The fiber flow split angle can be kept small, and the rolling fatigue life can be improved.

  Moreover, if the said groove part and an outer side rolling surface are formed concentrically with respect to the contact angle direction of the said outer side rolling surface and a ball | bowl like invention of Claim 5, turning allowance will be sufficient. This makes it possible to reduce the number of processing steps and to reduce the material loss by minimizing the input amount of forging material, thereby reducing the cost of the product.

  According to the wheel bearing device of the present invention, the outer member in which the outer circumferential surface of the double-row arc-shaped cross section is formed on the inner periphery, and the cross-sectional circle that faces the outer rolling surface of the double-row on the outer periphery. A wheel comprising an inner member in which an arc-shaped double row inner rolling surface is formed, and a double row ball accommodated so as to roll between the inner member and both rolling surfaces of the outer member. In the bearing device, a counter bore is formed at an end of the outer rolling surface of the double row, and the counter bore protrudes slightly inward in the radial direction from a groove bottom of the outer rolling surface of the double row, Since it is formed in a tapered shape that gradually expands in the direction of the end face of the outer member, it can reduce processing man-hours and minimize material loss by minimizing the amount of forging material input, Product costs can be reduced. Furthermore, since the ball can be smoothly inserted while being guided by the tapered counterbore, the ball does not collide with the counterbore and drop off, and the ball is damaged by the collision. However, it is possible to improve the acoustic characteristics of the bearing and improve the reliability of the quality.

  According to the method for manufacturing a wheel bearing device according to the present invention, an outer member having a double-row outer rolling surface having an arc-shaped cross section on the inner periphery, and an outer rolling surface of the double row on the outer periphery. An inner member formed with a double-row inner rolling surface having an arc-shaped cross section, and a double-row ball accommodated so as to roll between the inner member and both rolling surfaces of the outer member. In the manufacturing method of a wheel bearing device provided, the outer member is formed by forging while leaving a predetermined turning allowance, and in this forging process, the groove corresponding to the outer rolling surface of the double row is cross-sectioned. The counter bore is formed in a circular arc shape, and the counter bore is formed in a tapered shape at the end of the groove. Thereafter, a part of the counter bore is not processed, and the double-row outer rolling surface is turned and ground. Can reduce the number of processing steps. Together, it is possible to reduce the material losses with minimal input of the forging material.

  An outer member having a body mounting flange integrally attached to the vehicle body on the outer periphery, a double row outer rolling surface having an arc cross section formed on the inner periphery, and a wheel mounting for mounting a wheel on one end A hub having an integral flange and having an inner rolling surface having an arcuate cross section facing the outer rolling surface of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface. A ring, and an inner ring that is press-fitted into a small-diameter step portion of the hub ring via a predetermined squeeze and has an inner raceway having an arcuate cross section on the outer periphery and facing the outer raceway of the double row In the manufacturing method of a wheel bearing device, comprising: an inner member, and a double row of balls accommodated so as to roll between the inner member and the outer member. Is formed by forging while leaving a predetermined turning allowance from a round bar. In the manufacturing process, a groove corresponding to the outer rolling surface of the double row is formed in an arc shape in cross section, a counter bore is formed in a taper shape in a tangential direction of the groove, and then a part of the counter bore is The double row outer rolling surfaces are formed into a predetermined shape and size by turning and grinding without being processed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing an embodiment of a wheel bearing device according to the present invention, FIG. 2 is a sectional view showing a single outer member in FIG. 1, and FIG. 3 is a view of the vicinity of a rolling surface in FIG. FIG. 4 is an enlarged view and FIG. 4 is an explanatory view showing the fiber flow observed in the cross section of the outer member in FIG.

  This wheel bearing device is for a drive wheel called the third generation, and is an inner member 1, an outer member 2, and a double row of balls 3 accommodated between both members 1 and 2 so as to roll freely. 3 are provided. The inner member 1 includes a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4 through a predetermined shimiro.

  The hub wheel 4 integrally has a wheel mounting flange 6 for mounting a wheel (not shown) at an end portion on the outer side, and one (outer side) inner rolling surface having an arcuate cross-sectional shape on the outer periphery. 4a and a small diameter step portion 4b extending in the axial direction from the inner rolling surface 4a are formed, and a serration (or spline) 4c for torque transmission is formed on the inner periphery. Hub bolts 6a are planted on the wheel mounting flange 6 at equal intervals in the circumferential direction.

  The inner ring 5 is formed with the other (inner side) inner rolling surface 5a having an arcuate cross-sectional shape on the outer periphery, and is press-fitted into the small-diameter stepped portion 4b of the hub ring 4 so that a back-to-back type double-row angular ball bearing is provided. It is composed. The inner ring 5 and the ball 3 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core part by quenching.

  The hub wheel 4 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner raceway surface 4a and the base portion 6b on the inner side of the wheel mounting flange 6 are connected to the small diameter step portion 4b. Thus, the surface hardness is set to a range of 58 to 64 HRC by induction hardening. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 6, and the fretting resistance of the small-diameter step portion 4 b serving as the fitting portion of the inner ring 5 is improved.

  The outer member 2 integrally has a vehicle body mounting flange 2b to be attached to a knuckle (not shown) on the outer periphery, and the inner rolling surface 4a of the hub wheel 4 and the inner rolling surface 5a of the inner ring 5 on the inner periphery. Double row outer rolling surfaces 2a, 2a each having an arcuate cross-sectional shape facing each other are integrally formed. Double-row balls 3 and 3 are accommodated between these rolling surfaces, and are held by the cages 7 and 7 so as to be freely rollable.

  This outer member 2 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 2a and 2a have a surface hardness of 58 to 64HRC by induction hardening. Has been cured. Seals 8 and 9 are attached to the opening of the annular space formed between the outer member 2 and the inner member 1, and leakage of grease sealed inside the bearing and rainwater from the outside. And dust are prevented from entering the bearing. In addition, although the 3rd generation structure by the side of a drive wheel was illustrated here, it is not restricted to this, In the 1st thru | or 4th generation structure, the outer side of the double row which consists of circular-shaped cross-sectional shape in the inner periphery of an outer member A rolling surface may be formed.

  In the present embodiment, the outer member 2 is formed into a predetermined forging shape as shown in FIG. 2 by forging from a round bar or pipe material as a raw material (indicated by a two-dot chain line in the figure). . That is, the seal fitting surfaces 13, 14 on which the seals 8, 9 are mounted, including the inner side surface 10, outer diameter surface 11, and both end surfaces 12, 12 of the vehicle body mounting flange 2b with which the knuckle (not shown) abuts. From the counter bores 15 and 16, forging is performed with a predetermined turning allowance remaining in the inner circumferential portion extending over the double row outer rolling surfaces 2 a and 2 a and the inner diameter surface 17.

  Here, the counter bores 15 and 16 of the outer member 2 in the present embodiment slightly protrude radially inward, leaving the groove bottoms of the double row outer rolling surfaces 2a and 2a, and the seal fitting surfaces 13, It is formed in a tapered shape that gradually expands toward 14. A part of the counter bores 15 and 16 is left as a forged surface without being turned. That is, as shown in an enlarged view in FIG. 3, in the forging process, the groove portion 18 corresponding to the outer rolling surface 2 a is formed in an arc shape in cross section, and the counter bore 15 (16) is formed in the tangential direction of the groove portion 18. Has been. Therefore, the arc surface of the groove 18 and the outer rolling surface 2a are concentric with respect to the contact angle α direction between the outer rolling surface 2a and the ball 3, and the turning allowance is uniform and the amount of turning is reduced. In addition, the number of processing steps can be reduced. In addition, it is possible to reduce the material loss by minimizing the input amount of the forging material and to reduce the cost of the product.

  Further, by forming the outer member 2 in such a forged shape, as shown in FIG. 4, the fiber flow of the groove portions 18 and 18 corresponding to the double row outer rolling surfaces 2a and 2a is caused by these outer rolling. Since it is formed substantially parallel along the surface 2a, the split angle of the fiber flow divided by the formation of the outer rolling surface 2a can be kept small, and the rolling fatigue life can be improved.

  Further, in the outer member 2 in the present embodiment, the counter bores 15 and 16 are formed so as to slightly protrude radially inward from the groove bottoms of the double row outer rolling surfaces 2a and 2a, and the seal fitting surface Since it is formed in a tapered shape that gradually expands toward 13 and 14, the ball 3 can be assembled smoothly in the assembly process. That is, in the assembly process of the bearing shown in FIG. 5, a state in which the balls 3 are held by the cage 7, that is, so-called ball cassettes are inserted into the double-row outer rolling surfaces 2a, 2a of the outer member 2, At this time, the ball 3 can be smoothly inserted while being guided by the counter bore 15. Therefore, the ball 3 does not collide with the counterbore 15 and falls off, and the ball 3 is not damaged by the collision, and the acoustic characteristics of the bearing are improved to improve the reliability of the quality. Can do.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The wheel bearing device according to the present invention can be applied to a wheel bearing device having a first to fourth generation structure regardless of whether it is for driving wheels or driven wheels.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is sectional drawing which shows the outer member single-piece | unit of FIG. It is a principal part enlarged view of the outward member of FIG. It is explanatory drawing which shows the fiber flow observed in the cross section of the outward member of FIG. It is explanatory drawing which shows the assembly process of the wheel bearing apparatus of FIG. It is a longitudinal cross-sectional view which shows the outward member of the conventional wheel bearing apparatus. It is explanatory drawing which shows the manufacturing process of the outward member of FIG. It is explanatory drawing which shows the fiber flow observed in the cross section of the outward member of FIG.

Explanation of symbols

1 ... Inner member 2 ... Outer member 2a ...・ ・ ・ ・ ・ ・ Outside rolling surface 2b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Car body mounting flange 3 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Ball 4 ······························ Hub wheel 4a, 5a・ Small diameter step 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner ring 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange 6a ・ ・ ・ ・ ・ ・... Hub bolt 6b ... Base 7 ... Cage 8, 9, ... ·············································································· 11 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ································································· ············· Seal fitting surfaces 15 and 16 ············································· ..... groove part 50 ..... outer member 50a ... Outer rolling surface 50b ......... Car body mounting flange 51 ... ・ ・ ・ ・ ・ Material 52 First intermediate material 53 Second intermediate material 53a, 53b Recessed portion 54 ········ disk part 55 ····················· Third intermediate material 6 ·························· 57 ... Outer diameter surfaces 59, 60 on the inner side of the outer member ... End faces 61, 62 ... Seals Mating surface 63, 64 ......... Counter bore 65 ... Inner diameter surface F ...・ ・ ・ ・ ・ Fiber flow α ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Contact angle

Claims (5)

An outer member having a double-row outer rolling surface with an arc cross section on the inner periphery, and an inner rolling surface with a double-row inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery. An inner member,
In the wheel bearing device comprising this inner member and a double row of balls accommodated so as to roll between both rolling surfaces of the outer member,
A counter bore is formed at the end of the outer rolling surface of the double row, and the counter bore projects slightly radially inward from the groove bottom of the outer rolling surface of the double row, and the end surface of the outer member A wheel bearing device characterized by being formed in a tapered shape that gradually expands in the direction.   The wheel bearing device according to claim 1, wherein a part of the counterbore is left forged. An outer member in which a double row outer rolling surface having a circular arc cross section is formed on the inner circumference;
An inner member in which a double-row inner rolling surface having an arc-shaped cross section facing the outer rolling surface of the double row is formed on the outer periphery;
In the manufacturing method of the wheel bearing device comprising this inner member and a double row of balls accommodated so as to roll between both rolling surfaces of the outer member,
The outer member is formed by forging while leaving a predetermined turning allowance, and in this forging process, a groove corresponding to the outer rolling surface of the double row is formed in a circular arc shape, and an end of the groove The counter bore is formed into a taper shape, and thereafter, a part of the counter bore is not processed, and the double row outer rolling surface is formed into a predetermined shape and size by turning and grinding. A method for manufacturing a wheel bearing device.   The wheel bearing device manufacturing method according to claim 3, wherein the counterbore is formed in a tangential direction of the groove.   The method for manufacturing a wheel bearing device according to claim 3 or 4, wherein the groove and the outer rolling surface are formed concentrically with respect to a contact angle direction between the outer rolling surface and the ball.

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