JP2008045699A - 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 reducing cost by reducing machining man-hours and a material loss while attaining weight reduction and miniaturization. <P>SOLUTION: An outer member 2 is formed of a round bar by forging with a predetermined turning allowance left. In this forging process, shoulder parts 17, 17 of double rows of outer rolling surfaces 2a, 2a are formed in tapered shape gradually reduced in diameter toward the axial center part of portions to be the double rows of outer rolling surfaces 2a, 2a, and a disk part 18 is provided almost in the middle. The disk part 18 is eliminated by punching and then formed into predetermined dimensions by turning. A punching direction is thereby enlarged in diameter, and the disk part 18 to be a punched chip part 19 can be smoothly eliminated. A punching stroke is shortened to reduce man-hours, and the eliminated punched chip part 19 is minimized to reduce the material loss, thereby reducing cost. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like, and more particularly, a wheel bearing device that achieves a reduction in cost by reducing processing man-hours and material loss while reducing the weight and size and manufacturing the wheel bearing device. It is about the 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 double row outer rolling surfaces 50a and 50a are formed on the inner periphery. Has been. 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 punched to form the inner diameter portion 56, whereby 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 part (a portion in FIG. 6) whose outer edge is defined by the line is between the outer raceway surfaces 50a and 50a of the double row, which are separated from the outer raceway surfaces 50a and 50a. Since the forging process is performed so as to be located in the vicinity of the outer rolling surface 50a, non-metallic inclusions can hardly be generated in the vicinity of the outer rolling surface 50a. The occurrence of peeling can be prevented and sufficient durability can be secured. In addition, since segregation can hardly occur near the outer raceway surface of these double rows, it is possible to improve the hardenability during induction hardening.
JP 2005-180627 A

  In such a conventional outer member 50, as shown in FIG. 8, recesses 53a and 53b are formed at the center of both axial end surfaces of the second intermediate material 53, respectively, and intermediate portions between these recesses 53a and 53b. A disc portion 54 is provided (indicated by a two-dot chain line in the figure). Then, this disc portion 54 is punched to punch a punched portion (shown by hatching in the figure) 57 to form an inner diameter portion 56, which is a portion of the double row outer rolling surfaces 50a, 50a. Since the disk portion 54 is provided in the central portion in the axial direction, not only does the punching stroke become longer and the processing man-hours increase, but also the material loss of the material increases and becomes an obstacle to cost reduction. It was. Therefore, in such a forging process of the outer member 50, it has been a problem to reduce the processing man-hours and how to reduce the material loss of the material.

  The present invention has been made in view of the above circumstances, and provides a wheel bearing device and a method for manufacturing the same that are reduced in weight and size while reducing costs by reducing processing man-hours and material loss. It is an object.

  In order to achieve the object, the invention according to claim 1 of the present invention is such that an outer member having a double row outer rolling surface formed on the inner periphery and an outer member facing the double row outer rolling surface on the outer periphery. An inner member provided with a double-row inner rolling surface, and a double-row rolling element group accommodated so as to be freely rollable between both inner and outer rolling surfaces of the inner member and the outer member. In the wheel bearing device, the shoulder portion of the double-row outer rolling surface has a tapered surface that gradually decreases in diameter toward the axial central portion between the double-row outer rolling surfaces.

  Further, as in the invention described in claim 2, the pitch circle diameter of the outer side rolling element group in the double row rolling element group is set larger than the pitch circle diameter of the inner side rolling element group. In addition, the outer member is formed such that the outer rolling surface on the outer side is larger in diameter than the outer rolling surface on the inner side due to the difference in the pitch circle diameter, and from the outer rolling surface on the outer side. The outer rolling surface on the inner side may be formed through a cylindrical shoulder, a tapered step, and a cylindrical shoulder on the small diameter side.

  Further, as in the invention described in claim 3, the inner member integrally has a wheel mounting flange for mounting a wheel at one end portion, and faces the outer rolling surface of the double row on the outer periphery. One inner rolling surface, a hub ring formed with a small-diameter step portion extending in the axial direction from the inner rolling surface, and a small-diameter step portion of the hub ring are press-fitted through a predetermined shimiro, and the above-mentioned compound is formed on the outer periphery. The inner ring is formed with the other inner rolling surface facing the outer rolling surface of the row, and a mortar-shaped recess is formed at the outer end of the hub wheel. Is at least near the groove bottom of the inner raceway surface of the hub wheel, and the outer shape of the hub wheel is formed to have a substantially uniform thickness corresponding to the recess, the weight of the device is reduced.・ Resolves conflicting issues of compactness and high rigidity.

  According to a fourth aspect of the present invention, there is provided an outer member having a double-row outer rolling surface formed on the inner periphery, and a double-row inner rolling facing the outer rolling surface of the double row on the outer periphery. A method for manufacturing a wheel bearing device, comprising: an inner member provided with a surface; and a double row rolling element group that is rotatably accommodated between both rolling surfaces of the inner member and the outer member. In the forging process, the outer member is formed by forging while leaving a predetermined turning allowance from a round bar, and in this forging process, the shoulder portion of the outer surface of the double row is turned to the outer side of the double row. It is formed in a taper shape that gradually decreases in diameter toward the central portion in the axial direction of the portion that should become the running surface, and a disk part is provided in the middle of the part, and this disk part is deleted by punching, and then turned. A predetermined dimension is formed by processing.

  According to the wheel bearing device of the present invention, the shoulder of the double-row outer rolling surface of the outer member is gradually tapered toward the axial central portion between the outer rolling surfaces of the double-row. Since it has a surface, it can improve the plastic fluidity of the material in the forging process and improve the machining accuracy, and during operation, the grease enclosed in the bearing will move along this shoulder by gravity and centrifugal force. Therefore, the lubrication environment can be maintained in a good state.

  According to the method for manufacturing a wheel bearing device according to the present invention, the outer member is formed by forging while leaving a predetermined turning allowance from a round bar, and in this forging process, double rows of outer rolling surfaces are formed. Is formed in a tapered shape that gradually decreases in diameter toward the central portion in the axial direction of the portion that should be the outer rolling surface of the double row, and a disc portion is provided in the middle thereof. Since the part is deleted by punching and then formed into a predetermined dimension by turning, the diameter of the punching direction is expanded, and the disk part that becomes the punched part can be smoothly deleted. Therefore, the punching stroke can be shortened and the number of man-hours can be reduced, and the number of punched portions to be deleted can be reduced as much as possible, so that material loss can be reduced and the cost can be reduced.

  A body mounting flange for mounting to the vehicle body on the outer periphery, an outer member having a double row outer raceway formed on the inner periphery, and a wheel mounting flange for mounting a wheel on one end are integrated. A hub wheel having one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, a small diameter step portion extending in the axial direction from the inner rolling surface, and a small diameter of the hub wheel An inner member formed of an inner ring that is press-fitted into a step portion through a predetermined squeeze and has an inner ring formed on the outer periphery and facing the outer rolling surface of the double row; the inner member and the inner member In a manufacturing method of a wheel bearing device including a double row ball group that is rotatably accommodated between both rolling surfaces of an outer member, the outer member leaves a predetermined turning allowance from a round bar. In this forging process, the double-row outer rolling surface is The portion is formed in a tapered shape that gradually decreases in diameter toward the central portion in the axial direction of the portion that should be the outer rolling surface of the double row, and a disc portion is provided in the middle of the disc portion. It is deleted by punching, and then formed into a predetermined dimension by turning.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, FIG. 2 is a sectional view showing a single outer member of FIG. 1, and FIG. 3 is a modification of FIG. It is sectional drawing shown. 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).

  This wheel bearing device is for a drive wheel called the third generation, and is a double row rolling element housed in a freely rollable manner between the inner member 1, outer member 2, and both members 1,2. (Ball) 3 and 3 groups. 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 has one (outer side) inner rolling surface 4a on the outer periphery and the inner rolling surface. A small diameter step 4b extending in the axial direction from the surface 4a is 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 on the outer periphery, and is press-fitted into the small-diameter step portion 4b of the hub ring 4 to constitute a back-to-back type double-row angular ball bearing. The inner ring 5 and the rolling element 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 made 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 6c on the inner side of the wheel mounting flange 6 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 and 2a that are respectively opposed to each other are integrally formed. Double-row rolling elements 3 and 3 are accommodated between these rolling surfaces and are held by the cages 7 and 7 so as to roll freely.

  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 double row angular contact ball bearing which used the ball for the rolling element 3 was illustrated here, not only this but the double row tapered roller bearing which uses the tapered roller for the rolling element 3 may be sufficient. Further, the present invention is not limited to the third generation structure on the driving wheel side, and may be the first and second generation, third generation or fourth generation structure on the driven wheel side.

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

  Here, the shoulder portions 17 and 17 are not cylindrical, but are formed in a tapered shape that gradually decreases in diameter toward the central portion in the axial direction of the portion to be the double row outer rolling surfaces 2a and 2a. A disc portion 18 is provided. Then, a punched portion (indicated by hatching in the figure) 19 is punched out of the disk portion 18 and, after the forging process, shoulder portions 17 and 17 are formed with a predetermined inner diameter by turning. Thereby, the plastic fluidity | liquidity of the raw material in a forge process can be improved, and a processing precision can be improved. Furthermore, since the portions that should become the shoulder portions 17 and 17 are formed in a tapered shape, the punching direction (arrow) is expanded in diameter, and the punched portion 19 can be smoothly removed. Therefore, the punching stroke can be shortened and the number of man-hours can be reduced, and the number of punched-up portions 19 to be deleted can be reduced as much as possible to reduce the material loss, thereby reducing the cost.

  Further, since the shoulder portions 17 and 17 are formed in a tapered shape that gradually decreases in diameter toward the axial center of the double row outer rolling surfaces 2a and 2a, the grease enclosed in the bearing during operation is reduced. As the hub wheel 4 rotates, it flows along the shoulders 17 and 17 by gravity and centrifugal force and smoothly flows into the double-row outer rolling surfaces 2a and 2a, so that the lubrication environment is always in a good state. Can be maintained.

  An outer member 2 ′ shown in FIG. 3 is a modification of FIG. 2. The outer member 2 ′ is basically different from the above-described outer member 2 only in the configuration of the counter portion, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted. The counter portions 15 ′ and 16 ′ of the outer member 2 ′ are formed so as to slightly protrude from the groove bottom so that the rolling elements 3 held by the cage 7 do not fall off in the axial direction. Thereby, the plastic fluidity of the raw material in the forging process can be further increased, the processing accuracy can be improved, and the material loss can be reduced.

  4 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention, and FIG. 5 is a sectional view showing a single outer member of FIG. In addition, the same code | symbol is attached | subjected to the component same site | part or the site | part which has the same function as embodiment mentioned above, and detailed description is abbreviate | omitted.

  This wheel bearing device is for a driven wheel called the third generation, and is an inner member 20, an outer member 21, and a double-row rolling element housed between the members 20, 21 so as to roll freely. (Ball) 3 and 3 groups. The inner member 20 includes a hub ring 22 and an inner ring 5 that is press-fitted into the hub ring 22 through a predetermined shimiro.

  The hub wheel 22 integrally has a wheel mounting flange 6 at an end portion on the outer side, one (outer side) inner rolling surface 22a on the outer periphery, and the shaft-like portion 23 from the inner rolling surface 22a. A small diameter step 22b extending in the axial direction is formed. The inner ring 5 is press-fitted into the small-diameter step portion 22b and is fixed in the axial direction by a crimping portion 22c formed by plastically deforming an end portion of the small-diameter step portion 22b radially outward. A circular hole 6b is formed between the hub bolts 6a, which contributes to weight reduction, and a fastening jig such as a wrench can be inserted from the circular hole 6b in the assembly / disassembly process of the apparatus, thereby simplifying the work. can do.

  The hub wheel 22 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner raceway surface 22a and the inner side base portion 6c of the wheel mounting flange 6 to the small diameter step portion 22b. Thus, the surface hardness is set to a range of 58 to 64 HRC by induction hardening. The caulking portion 22c is left as it is after forging.

  The outer member 21 has a vehicle body mounting flange 2b integrally on the outer periphery, and a double row outer rolling surface facing the inner rolling surface 22a of the hub wheel 22 and the inner rolling surface 5a of the inner ring 5 on the inner periphery. 21a and 21b are integrally formed. Double row rolling elements 3 and 3 are accommodated between these rolling surfaces and are held by the cages 24 and 7 so as to be freely rollable. This outer member 21 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 21a and 21b have a surface hardness in the range of 58 to 64HRC by induction hardening. Has been cured.

  In this embodiment, the pitch circle diameter PCDo of the outer side rolling element 3 group is set larger than the pitch circle diameter PCDi of the inner side rolling element 3 group. The sizes of the rolling elements 3 and 3 are the same, but due to the difference in the pitch circle diameters PCDo and PCDi, the number of rolling elements in the outer rolling element group 3 is greater than the number of rolling elements in the inner rolling element group 3. There are also many settings. As a result, the bearing space can be effectively utilized to increase the bearing rigidity of the outer side portion compared to the inner side, and the life of the bearing can be extended. In addition, the size of the inner side rolling element 3 group and the outer side rolling element 3 group may be different.

  The outer shape of the hub wheel 22 is such that a shoulder portion 23b with which the inner ring 5 is abutted against the counter portion 25 from the groove bottom portion of the inner rolling surface 22a and the shaft portion 23 and the tapered step portion 23a from the counter portion 25. Is formed. A mortar-shaped recess 26 is formed at the outer end of the hub wheel 22. The depth of the recess 26 is a depth up to the vicinity of the groove bottom of the inner rolling surface 22a, and the end portion on the outer side of the hub wheel 22 is formed to have a substantially uniform thickness. Thereby, it is possible to solve the conflicting problems of light weight, compactness and high rigidity of the apparatus.

  On the other hand, in the outer member 21, the outer side outer rolling surface 21a is formed with a larger diameter than the inner side outer rolling surface 21b in accordance with the difference between the pitch circle diameters PCDo and PCDi. From the running surface 21a, the cylindrical shoulder portion 27 and the tapered step portion 27a are followed by the cylindrical shoulder portion 28 on the small diameter side and the inner side outer rolling surface 21b. And it forms so that the groove bottom diameter of this outer side rolling surface 21b and the internal diameter of the large diameter side shoulder part 27 may become substantially the same diameter.

  Here, the outer member 21 is formed into a predetermined forging shape as shown in FIG. 5 by a forging process from a round bar material as a raw material (indicated by a two-dot chain line in the figure). That is, from the side surface 10 on the inner side of the vehicle body mounting flange 2b to the outer peripheral surface 11 and both end surfaces 12, 12, and the seal fitting surfaces 13, 14 to which the seals 8, 9 are attached, the counter portions 15, 16, and Forging is performed in a state where a predetermined turning allowance is left on the inner peripheral surface extending over the outer rolling surfaces 21a, 21b and the shoulder portion 28 of the row.

  In the present embodiment, the inner peripheral surface on the outer side is forged along a tapered step portion 27a, and a disk is provided approximately in the middle (A≈B) between the portions to be the double row outer rolling surfaces 21a and 21b. A portion 29 is provided. Then, a punched portion (indicated by hatching in the figure) 30 is punched out from the disk portion 29, and after the forging step, a shoulder portion 28 is formed with a predetermined inner diameter by turning. Thereby, the plastic fluidity | liquidity of the raw material in a forge process can be improved, and a processing precision can be improved. Further, since the step 27a is formed in a taper shape, the punching direction (arrow) is expanded in diameter, and the punched portion 30 can be removed smoothly. Accordingly, the punching stroke can be shortened and the number of man-hours can be reduced, and the punched-up portions 30 to be deleted can be reduced as much as possible to reduce the material loss, thereby reducing the cost.

  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 a 1st embodiment of a bearing device for wheels concerning the present invention. It is sectional drawing which shows the outer member single-piece | unit of FIG. It is sectional drawing which shows the modification of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is sectional drawing which shows the outward member single-piece | unit 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 sectional drawing which shows an outer member single-piece | unit same as the above.

Explanation of symbols

1, 20 ..... Inner member 2, 2 ', 21 ..... Outer member 2a, 21a, 21b ... Outer rolling surface 2b ... Body mounting flange 3 ... Rolling elements 4, 22 ... ... hub wheels 4a, 5a, 22a ... inner rolling surfaces 4b, 22b ... small diameter step 5 ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner ring 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange 6a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Hub bolt 6b ..... round hole 6c ..... base 7, 24 ... Cage 8, 9, ... Seal 10 ... Car Side 11 on the inner side of the body mounting flange ......... Outer peripheral surface 12 on the inner side of the outer member ... End faces 13 and 14 of the side members ········ Seal fitting surfaces 15, 15 ', 16, 16', 25 ··· Counter portions 17, 23b ········・ ・ Shoulders 18, 29 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Disk parts 19, 30 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Punchas 23 …… ... Shaft-shaped parts 23a, 27a ... Step part 26 ... Recess 27 ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shoulder 28 on the large diameter side ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shoulder 50 on the small diameter side ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・Outer member 50a ... Outer rolling surface 50b ... ... Body mounting flange 51 ... Material 52 ... First intermediate material 53 ························ Second intermediate material 53a, 53b ············ 54 Part 55 ... 3rd intermediate material 56 ... Inner diameter part 57 ...・ ・ ・ ・ ・ Ponchicus part PCDi ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter of the inner side rolling element PCDo ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Rolling element on the outer side Pitch circle diameter

Claims (4)

An outer member having a double row outer raceway formed on the inner periphery;
An inner member provided on the outer periphery with a double-row inner rolling surface facing the double-row outer rolling surface;
In the wheel bearing device including the inner member and a double row rolling element group accommodated in a freely rolling manner between both rolling surfaces of the outer member,
A bearing device for a wheel, wherein a shoulder portion of the outer raceway surface of the double row has a tapered surface that gradually decreases in diameter toward an axial central portion between the outer raceway surfaces of the double row. .   The pitch circle diameter of the outer side rolling element group in the double row rolling element group is set larger than the pitch circle diameter of the inner side rolling element group, and the outer member has the pitch circle diameter. Accordingly, the outer rolling surface on the outer side is formed with a diameter larger than the outer rolling surface on the inner side, and a cylindrical shoulder portion, a tapered step portion, and a cylinder are formed from the outer rolling surface on the outer side. 2. The wheel bearing device according to claim 1, wherein an outer rolling surface on the inner side is formed through a shoulder portion on the small diameter side.   From the inner rolling surface, the inner member integrally has a wheel mounting flange for mounting a wheel at one end, and is opposed to the outer rolling surface of the double row on the outer periphery. A hub wheel formed with a small-diameter step portion extending in the axial direction, and the other inner rolling member that is press-fitted into the small-diameter step portion of the hub wheel via a predetermined shimiro and faces the outer rolling surface of the double row on the outer periphery. A mortar-shaped recess is formed at the outer end of the hub wheel, and the depth of the recess is at least the groove bottom of the inner raceway surface of the hub wheel. The wheel bearing device according to claim 1 or 2, wherein the outer peripheral shape of the hub wheel is formed so as to have a substantially uniform thickness corresponding to the recess. An outer member having a double row outer raceway formed on the inner periphery;
An inner member provided on the outer periphery with a double-row inner rolling surface facing the double-row outer rolling surface;
In the method of manufacturing a wheel bearing device comprising the inner member and a double row rolling element group accommodated in a freely rolling manner between both rolling surfaces of the outer member,
The outer member is formed by forging while leaving a predetermined turning allowance from a round bar, and in this forging process, the shoulder of the outer rolling surface of the double row is the outer rolling surface of the double row. It is formed in a taper shape that gradually decreases in diameter toward the central part in the axial direction of the portion to be, and a disk part is provided in the middle of the part, and this disk part is deleted by punching, and then by turning A method for manufacturing a wheel bearing device, wherein the wheel bearing device is formed in a predetermined dimension.

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