JP6523677B2 - Method of manufacturing hub wheel and inner member of wheel bearing device - Google Patents

Description

  The present invention relates to a method of manufacturing a hub wheel and an inward member of a wheel bearing device for supporting a wheel of an automobile or the like, and more specifically, a wheel bearing device having a wheel mounting flange and serving as an outward member of a rotating wheel side. The present invention relates to a method of manufacturing a hub ring and an inner member.

  At present, lightweight, compact, and high-durability bearing devices are required with the improvement of fuel efficiency and performance of automobiles. There are two types of bearing devices for wheels of an automobile: one for driven wheels and one for driving wheels. The weight saving of the bearing devices for driven wheels is progressing, and the wheel mounting flange portion of the hub wheel is thinned to penetrate the inner circumference. There is something to make it a hole. The bearing device for the driven wheel fixes the inner member on the fixed wheel side to the vehicle body, and the hub wheel on the rotating wheel side is configured to support rotational force and load from the wheel.

  The hub wheel and the inward member of the wheel bearing device are each separately formed by forging a cylindrical steel material. For example, after the hub wheel is generally formed by forging, the surface scale is removed by shot blasting or the like. Then, a functional part such as an inner raceway is cut by a dedicated turning line, and transferred to an induction hardening process and a grinding process. A steel material such as S53C is mainly used for the hub ring formed by this forging process, and a portion such as the inner raceway is hardened by induction hardening.

  The column-shaped steel material used as the raw material of the hub ring of bearing apparatus for wheels, and an inward member is what cut | disconnected the elongate material of the cross-sectional circular shape extrusion-formed by the steel maker in predetermined length. Various inclusions are contained in this column-shaped steel material, and in the radial direction, a portion close to the center from the center to 40% of the radius or a nonmetallic inclusion on the outer peripheral surface side than 80% of the radius from the center Is known to be present and to be less clean. If a metal material with a low degree of cleanliness is exposed to a portion of the rolling contact surface provided on the circumferential surface of the bearing ring member, particularly where the rolling surface of the rolling element makes rolling contact, the rolling fatigue life of this portion may be reduced. There is.

  In order to solve these problems, at least the rolling elements are formed when a bearing ring member having an outward facing flange on the outer periphery and a double row of outer raceways formed on the inner periphery is formed by forging a cylindrical steel material A manufacturing method of the bearing ring member shown in FIG. 18 has been proposed in which the metal material of the highly clean intermediate cylindrical portion of the material is exposed to the portion to which the load acts.

  As shown in (A) → (B), the manufacturing method of this bearing ring member enlarges the outer diameter while crushing the material 101 in the axial direction, and expands the material 101 in the radial direction at the middle portion thereof. As shown in (B) → (C), a first upsetting step of forming the intermediate step intermediate material 102 axially compresses a radially central portion of the intermediate step intermediate material 102 in the axial direction, and A front / rear extrusion process in which the metal material 103 in the near portion is moved to both axial directions (both front and rear directions) while being moved radially outward and plastically processed into the second front stage intermediate material 104, (C) → As shown in (D), the radially central portion of the second front stage intermediate material 104 is axially pressed to crush this portion, and the partition portion 105 is formed as the partition portion 106 having a small thickness dimension. In the second upsetting process, as shown in (D) → (E), Ri and step, through a punching process shown in (E) → (F), is processed material 101 to the final intermediate material 115.

  In the second setting step of (C) → (D), many parts of the metal material 103 pushed out from the partition portion 105 existing between the two circular concave portions 107 and 108 are the mounting portions 109 ((F (See)), and since it exists in the radially outward portion between the center positions of the outer rolling surface 111a of the double row of the outer member 111, it is pushed out from the partition 106 A large portion of the metallic material 103 is not fed to the outer row rolling surface 111a, but is sent radially outward through the portion to be the outer row rolling surface 111a of the double row. Therefore, at the stage of the preliminary post-stage intermediate material 112 (post-stage intermediate material 113), the metal material 114 of the intermediate cylindrical portion with high cleanliness exists in the portion where the outer raceway surface 111a is to be formed later See, for example, Patent Document 1)

  However, in such a conventional forging process, not only burrs 110 but also a large amount of waste material called punches such as the partition wall portion 106 is generated, which is a cause of lowering the yield. A manufacturing method as shown in FIG. 19 in which the material yield is efficiently manufactured is known.

  This manufacturing method relates to so-called parent and child forging, in which the cylindrical steel material 120 shown in (a) is heated to a hot forming temperature and diameter-increased by upset processing between the upper mold and the lower mold (b) As shown in (c), the preformed product 121 shown in the drawing is preformed by punching into a preform 123 having a shallow dish-like depression 122 in the upper part of the processed workpiece 121. The thick annular body 125 is connected at its outer peripheral upper end to the upper thick annular body 124 shown in (d) from the preformed product 123 and the inner diameter lower portion of the upper thick annular body 124. The hot forging is performed by a punch and a die into a tower type parent and child forging product 129 consisting of a bottom portion 126 in the inner diameter of the lower end portion. As shown in (f), forging and separating the bottom portion 126 from the thick annular body 125 to the lower thick annular body 125 having the upper thick annular body 124 and the bottom portion 126 shown in (e). Do. These are continuously forged using one hot forging machine.

  Then, the separated upper thick annular body 124 is cold forged with a punch and a die to form an outer race form product 130 for the second tapered roller bearing at the upper periphery and an inner race form connected to the lower inner diameter thereof It is formed into a tower type parent and child forging product 132 shown in (g) consisting of the product 131. Further, the formed parent and child forged product 132 is cut and separated, and is separated into an outer race forming product 130 and an inner race forming product 131 for tapered roller bearings shown in (h), and a pair of race elements for the tapered roller bearings. Get the product. The lower thick annular body 125 is formed into a tower type parent and child forging 133 shown in (i) by the same manufacturing method. Further, the formed parent and child forged product 133 is cut and separated, and is separated into an outer race forming product 134 for the tapered roller bearing and an inner race forming product 135 shown in (j). Get the product.

  By this process, two sets of outer race molded products 130 and 134 and inner race molded products 131 and 135 having different model numbers and dimensions can be efficiently manufactured with high yield from one cylindrical steel material 120. These obtained molded race products are further subjected to a turning process to make a race for tapered roller bearings (see, for example, Patent Document 2).

JP, 2008-173677, A JP 2005-288505 A

  In the parent and child forging described above, two sets of outer race molded products 130 and 134 and inner race molded products 131 and 135 having different model numbers and dimensions can be manufactured with high yield from one cylindrical steel material 120. There has been a problem in arranging a hub ring and an inner member integrally having a wheel mounting flange as in a bearing device, for example, in an intermediate cylindrical portion with high cleanliness in a portion where a rolling surface is to be formed. .

  The present invention has been made in view of such circumstances, focusing on parent and child forging in which the hub ring and the inward member are simultaneously forged, to improve the yield and reduce the amount of material input, and to reduce the amount of inclusions. It is an object of the present invention to provide a method of manufacturing a hub ring and an inner member of a bearing device for a wheel, in which the life reduction due to the influence is reduced and the strength is improved.

  In order to achieve the above object, the invention according to claim 1 of the present invention is characterized by integrally including a wheel mounting flange for attaching a wheel at an end portion on the outer side, and a double row outer raceway surface on the inner periphery Between the two raceways of the inner ring and the hub wheel. In a method of manufacturing a hub ring and an inward member of a bearing device for a wheel including double-row rolling elements rotatably accommodated, a cylindrical steel material is heated to a hot forming temperature, and between an upper mold and a lower mold The diameter of the diameter is increased by upsetting process to make upset product, and the upset process product is a tower type parent and child consisting of an upper annular body and a lower annular body connected to an inner lower portion of the upper annular body at an outer peripheral upper end It is formed into a forged product, and this parent and child forged product is separated into the upper annular body and the lower annular body By Rukoto, and finishing products of the hub wheel and the inner member.

  Thus, the hub wheel integrally has a wheel mounting flange for attaching a wheel to the end on the outer side, and the double row of outer rolling surface is formed on the inner periphery, and the double row of outer rolling on the outer periphery For a wheel comprising an inner member in which inner rolling surfaces facing each other are formed, and a double row of rolling elements rollably housed between the inner member and both rolling surfaces of the hub wheel In a method of manufacturing a hub wheel and an inward member of a bearing device, a cylindrical steel material is heated to a hot forming temperature, and diameter expansion is performed between the upper and lower molds by upsetting to form a upset processed product. A processed product is formed into a tower type parent and child forging consisting of an upper annular body and a lower annular body connected to the lower inner diameter of the upper annular body at an outer peripheral upper end portion. By separating into the body, because it was a finished product of the hub ring and the inner member, The partition wall part which was punched out and discarded after forging of the wheel is used as it is as a material of the inward member to improve the yield and reduce the amount of material input, and the life reduction due to the influence of inclusions. It is possible to provide a method of manufacturing a hub wheel and an inner member of a wheel bearing device which is reduced and whose strength is enhanced.

  Preferably, as in the invention according to claim 2, the upset processed product is forward extruded using a mold corresponding to the outer peripheral surface shape of the roughly shaped product, and a shallow dish-like recess is provided on the upper part thereof; Arranged concentrically with each other in a rough forming process of forming into a rough product having a thick annular part and a shaft part, and in a die whose concavities and convexities are reversed corresponding to the outer peripheral surface shape of the intermediate formed product Between the pressed punch and the counter punch, the central portions of both end faces in the axial direction of the roughly shaped product are pressed, and the material in the radially central portion is moved in the axial direction while moving radially outward And filling the cavity surrounded by the inner peripheral surface of the die and the outer peripheral surface of the pressing punch and the counter punch, and forming a circular recess opening on one end surface side in the axial direction; , A circular recess opening on the other axial end side And forming the upper annular body while increasing the diameter of the inner peripheral surface while increasing the depth of the circular recess on one end side of the intermediate molded product, and at the same time the intermediate molding Finished by extruding the shaft of the product in the axial direction and punching out the shaft with the outer peripheral surface being the inner rolling surface of the inner member and the circular recess on the other end side to form a lower annular body with a through hole In the upper annular body which becomes a hub wheel, if a molding process is provided, the lower end of the portion where a large portion of the material from which the bottom of the circular recess is extruded is to be the outer raceway surface on the inner side of the hub wheel The material flows radially outward through the through hole, and the material of the less clean center-centered cylindrical part becomes the flange part, and the part where the outer rolling surface of the double row is formed is a highly clean intermediate cylindrical part Of the lower ring, which is the inner member, And a portion of the material from which the bottom of the circular recess is extruded flows radially outward through the upper end of the portion which is to be the inner rolling surface of the inner member, and the central portion is less clean In the portion where the material of the above becomes the outer diameter portion and the inner raceway surface of the inward member is formed, a large amount of material of the intermediate cylindrical portion with high cleanliness exists. Therefore, the life reduction due to the influence of inclusions can be reduced, and the strength can be improved.

  Further, as in the invention according to the third aspect, in a state where the support punch is inserted into the through hole of the lower annular body, the separate punch is pressed on almost the entire surface of the bottom of the circular recess of the upper annular body. By shearing between the upper annular body and the lower annular body, even if the pressure from the separate punch is applied to the lower annular body, the inside of the through hole located inside these is restrained by the support punch, so the lower side The annular body is less likely to be deformed, and only the shear force along the lowering direction of the separate punch is applied to the sheared surface in the lower annular body, so that both can be separated accurately and efficiently.

  Further, as in the invention according to claim 4, if the pitch circle diameter of the rolling elements on the outer side among the rolling elements of the double row is set smaller than the pitch circle diameter PCDi of the rolling elements on the inner side The forging process can be facilitated, the fiber flow can be formed along the double row outer raceway surface, and the rolling fatigue life can be improved.

  Further, as in the invention according to claim 5, if the outer raceway surface of the double row of the hub wheel is formed by cold forging after hot forging, the strength is increased by work hardening, and cutting in the post process is performed. The cutting allowance of processing can be reduced and simplified.

  Further, as in the invention according to claim 6, the inner ring member has an inner race member on the outer periphery of which an inner race surface opposed to one of the outer race surfaces of the double row, and the inner ring member A vehicle mounting system comprising an inner ring press-fitted and having an inner rolling surface formed on the outer periphery opposite to the other of the double row outer rolling surfaces and mounted on the inner side of the inner member on the vehicle body The flange or the mounting portion may be integrally formed.

  Further, as in the invention according to claim 7, if at least one of the inner ring member and the inner ring is formed by cold forging after hot forging, along with the increase in strength by work hardening, in the cutting process of the post process The cutting allowance can be reduced and simplified.

  A method of manufacturing a hub wheel and an inner member of a bearing device for a wheel according to the present invention integrally includes a wheel mounting flange for attaching a wheel at an end portion on an outer side, and double rows of outer raceway surfaces on an inner periphery. Between the two raceways of the inner ring and the hub wheel. In a method of manufacturing a hub ring and an inward member of a bearing device for a wheel including double-row rolling elements rotatably accommodated, a cylindrical steel material is heated to a hot forming temperature, and between an upper mold and a lower mold The diameter of the diameter is increased by upsetting process to make upset product, and the upset process product is a tower type parent and child consisting of an upper annular body and a lower annular body connected to an inner lower portion of the upper annular body at an outer peripheral upper end It is formed into a forged product, and this parent and child forged product is made into the upper annular body and the lower annular body Since the hub wheel and the inward member are finished by separating them from each other, the partition portion which has been punched and discarded after forging the hub wheel is effectively utilized as it is as a material of the inward member. It is possible to provide a method of manufacturing a hub ring and an inward member of a bearing device for a wheel, which is improved to reduce the amount of material input, reduce the life reduction due to the influence of inclusions, and improve the strength.

1 is a longitudinal sectional view showing a first embodiment of a bearing device for a wheel according to the present invention. (A)-(h) is process drawing which shows the front process concerning the manufacturing method of the hub ring of FIG. 1, and an inward member. (A)-(f) is process drawing which shows the back process concerning the manufacturing method of the hub ring of FIG. (A)-(e) is process drawing which shows the back process which concerns on the manufacturing method of the inward member of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the bearing apparatus for wheels which concerns on this invention. (A)-(h) is process drawing which shows the front process concerning the manufacturing method of the hub ring of FIG. 5, and an inward member. (A)-(f) is process drawing which shows the back process concerning the manufacturing method of the hub ring of FIG. (A)-(d) is process drawing which shows the back process concerning the manufacturing method of the inward member of FIG. It is a longitudinal cross-sectional view which shows 3rd Embodiment of the bearing apparatus for wheels which concerns on this invention. (A)-(h) is process drawing which shows the front process concerning the manufacturing method of the hub ring of FIG. 9, and an inward member. (A)-(e) is process drawing which shows the back process concerning the manufacturing method of the hub wheel of FIG. (A)-(f) is process drawing which shows the post process which concerns on the manufacturing method of the inner ring | wheel of FIG. It is a longitudinal cross-sectional view which shows 4th Embodiment of the bearing apparatus for wheels which concerns on this invention. (A)-(h) is process drawing which shows the front process concerning the manufacturing method of the hub ring of FIG. 13, and an inward member. (A)-(e) is process drawing which shows the back process concerning the manufacturing method of the hub ring of FIG. (A)-(f) is process drawing which shows the post process which concerns on the manufacturing method of the inner ring | wheel of FIG. (A)-(f) is process drawing which shows the post process which concerns on the manufacturing method of the inner ring member of FIG. It is process drawing which shows the manufacturing method of the conventional bearing ring member. It is process drawing which shows the manufacturing method of the conventional tapered roller bearing race raw material goods.

  A wheel mounting flange for attaching a wheel is integrally formed at the end on the outer side, and a hub wheel having a double row of outer raceways formed on the inner periphery, and an outer raceway surface of the double rows on the outer periphery Bearing apparatus for a wheel comprising an inward member in which respective inward rolling surfaces are formed, and a double-row rolling element rotatably accommodated between the inward member and both rolling surfaces of the hub wheel In the hub wheel and inner member manufacturing method of the present invention, a cylindrical steel material is heated to a hot forming temperature, and diameter expansion is carried out between the upper mold and the lower mold by upsetting to obtain a upset processed product, and this upset processed product Rough forming is performed by forward extrusion using a mold corresponding to the outer peripheral surface shape of the rough shaped product, and forming into a rough shaped product having a shallow dish-like recess at the top, a thick annular portion and a shaft-like portion In a state where it is set in a die in which the unevenness is reversed corresponding to the process and the outer peripheral surface shape of the intermediate molded product, Center portions of both end faces in the axial direction of the roughly shaped product between the pressing punch and the counter punch, which are disposed concentrically, and the material of the radially central portion is moved radially outward A circular recess which is axially moved to fill in a cavity surrounded by the inner peripheral surface of the die and the outer peripheral surface of the pressing punch and the counter punch, and which is open on one axial end surface side; The inner peripheral surface, while increasing the depth of the circular recess on one end side of the intermediate molded product, in an intermediate molding step of forming into a shaft-like portion having a flange portion and a circular recess opening on the other axial end surface side. And the axial portion of the intermediate molded product is pushed out in the axial direction and the outer peripheral surface becomes the inner rolling surface of the inward member, and the other end side Lower annular part having a through hole by punching out a circular recess And a finishing forming step of forming the parent-child forgings made of, said upper annular body and a lower annular body is forged separated.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a bearing device for a wheel according to the present invention, and FIGS. 2 (a) to 2 (h) are front views related to a method of manufacturing a hub ring and an inner member of FIG. FIGS. 3 (a) to 3 (f) are process diagrams showing subsequent steps according to the method of manufacturing the hub ring of FIG. 1, and FIGS. 4 (a) to 4 (e) are inwards of FIG. It is process drawing which shows the back process concerning the manufacturing method of a member. In the following description, the side closer to the outer side of the vehicle in a state of being assembled to the vehicle is referred to as the outer side (left side in FIG. 1) and the side closer to the center as the inner side (right side in FIG. 1).

  The wheel bearing device shown in FIG. 1 is for an outer ring rotation type driven wheel, and is a double row in which the inner member 1 and the hub ring (outer member) 2 and the two rows 1 and 2 are rotatably accommodated. Rolling elements (balls) 3 and 3 are provided. The inner member 1 includes a first inner ring member 4 and a second inner ring member (inner ring) 5 press-fitted into the first inner ring member 4.

  The first inner ring member 4 has an annular shape, and an outer side inner raceway surface 4a and a cylindrical small diameter step 4b axially extending from the inner raceway surface 4a are formed on the outer periphery. On the other hand, the second inner ring member 5 extends radially outward from the outer diameter side of the inner side rolling surface 5a on the outer circumference and the inner rolling surface 5a on the outer periphery, and is mounted on the vehicle body mounting flange 6 Is integrally formed, and a cylindrical pilot portion 7 is formed on the inner side of the vehicle body mounting flange 6. A female screw 6 b for fastening to the vehicle body is formed equidistantly in the circumferential direction of the vehicle body mounting flange 6.

  The second inner ring member 5 is press-fit into the small diameter step 4b of the first inner ring member 4 through a predetermined space, and the end portion of the small diameter step 4b is plastically deformed radially outward and formed It is axially fixed by the part 4c.

  The first inner ring member 4 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and is in the range of 50 to 64 HRC for induction hardening from the inner raceway surface 4a to the small diameter step 4b. The surface is hardened. In addition, the crimped part 4b is made to be raw of the surface hardness after forge processing. As a result, the fretting resistance of the small diameter step portion 4b which is the fitting portion of the second inner ring member 5 is improved, and the plastic working of the crimped portion 4c can be smoothly performed without the occurrence of minute cracks and the like. .

  Similar to the first inner ring member 4, the second inner ring member 5 is formed of a medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53 C, or a high carbon chromium steel such as SUJ 2 In this case, the surface is hardened in the range of 50 to 64 HRC by induction hardening from the base 6a on the outer side of the vehicle body mounting flange 6 serving as the land portion of the seal 11 described later to the inner raceway surface 5a. On the other hand, in the case of high carbon chromium steel, the core portion is hardened to a range of 58 to 64 HRC by squib hardening. Further, the rolling element 3 is formed of high carbon chromium steel such as SUJ 2 and is hardened to a range of 62 to 67 HRC up to the core portion by slip hardening.

  The hub wheel 2 integrally has a wheel mounting flange 8 for attaching a wheel (not shown) on the outer periphery of the end on the outer side, and faces the inner raceway surfaces 4a and 5a of the inner member 1 on the inner periphery. Double rows of outer raceways 2a, 2b are formed. The double rows of rolling elements 3, 3 are rotatably accommodated between the both rolling surfaces 2a, 4a and 2b, 5a via the cages 9, 10, respectively. The wheel mounting flange 8 has circumferentially equally spaced hub bolts 8a for fixing the wheels.

  The hub wheel 2 is formed of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and at least double row outer raceway surfaces 2a and 2b are hardened by induction hardening in the range of 50 to 64 HRC It is done. Further, the seal 11 is attached to the inner end of the hub wheel 2 and an inner diameter 2c is formed on the inner periphery of the outer end, and an end cap (not shown) is attached to the inner diameter 2c. It is done. The seal 11 and the end cap prevent the leakage of the lubricating grease sealed in the inside of the bearing and prevent the intrusion of rain water, dust, etc. from the outside into the inside of the bearing. In place of the cap, a seal (not shown) may be attached between the inner diameter portion 2 c of the hub wheel 2 and the outer diameter portion of the first inner ring member 4.

  In the present embodiment, the pitch circle diameter PCDo of the outer rolling element 3 is set smaller than the pitch circle diameter PCDi of the inner rolling element 3 (PCDo <PCDi). And although the size of the double row rolling elements 3 is the same, the number of rolling elements 3 on the inner side is set larger than the number of rolling elements 3 on the outer side due to the difference between the pitch circle diameters PCDo and PCDi. It is done. By adopting such a configuration, it is possible to effectively utilize the bearing space to increase the bearing rigidity of the inner side portion as compared with the outer side, and to prolong the life of the bearing. In addition, forging to be described later can be facilitated, fiber flow can be formed along the double rows of outer raceway surfaces 2a and 2b, and rolling fatigue life can be improved. In the present embodiment, the double row angular contact ball bearing structure using balls for the rolling elements 3 is exemplified, but the invention is not limited thereto. For example, double row conical roller bearing structure using conical rollers for the rolling elements 3 It may be.

  Here, in the present embodiment, as shown in FIG. 2A, the bar material is cut into a predetermined length, and this cylindrical steel material 12 is hot-formed at a transformation point temperature of 1150 ° C. to 1200 ° C. Then, as shown in (b), the diameter is increased by upset processing between the upper and lower molds to obtain a upset processed product 13. Furthermore, as shown in (c), in the rough forming step, this upset product 13 is forward extruded using a mold corresponding to the outer peripheral surface shape of the rough product 14, and a shallow dish-like recess is formed on the upper part It is formed into a roughly shaped product 14 having a thick portion 14a and a thick annular portion 14b and a shaft portion 14c.

  Next, in the upsetting process shown in (d), the pressing punch and the counterpunch arranged concentrically with each other in a state of being set in a die whose concavity and convexity are reversed corresponding to the outer peripheral surface shape of the intermediate molded product 15 And press the center portions of both end faces in the axial direction of the roughly shaped product 14 and move the material in the radially central portion to the intermediate molded product 15 by moving the material radially outward while moving the material radially outward. To mold. Here, with the counter punch disposed at the lower side fixed, the pressing punch disposed at the upper side is pressed against the counter punch. Then, the material of the roughly shaped product 14 is moved to fill the cavity surrounded by the inner peripheral surface of the die and the outer peripheral surface of the pressing punch and the counter punch, and a circular opening in one axial end surface side (upper part) It is formed into a shaft-like portion 19 having a recessed portion 16, a flange portion 17 serving as a wheel mounting flange portion, and a circular recessed portion 18 opened on the other end surface side (lower portion) in the axial direction. The shaft-like portion 19 of the intermediate molded product 15 serves as an inward member (first inner ring member).

  Next, in the finish forming step shown in (e), while increasing the depth of the circular recess 16 of the intermediate molded product 15, the diameter of the inner peripheral surface is increased to form an upper annular body having the circular recess 20 and the flange portion 21 A tower type parent-child forging 24 which is connected to a parent member 22 and a lower inner diameter lower portion of the upper annular body 22 at an outer peripheral upper end portion of a lower annular body (child member) 23 and a bottom portion of the lower annular body 23 It is molded. At the same time, the shaft-like portion 19 of the intermediate molded product 15 is pushed out in the axial direction, and the outer circumferential surface becomes the inner rolling surface of the inward member. It is formed into an annular body 23. In this finishing step, as in the setting step of (d) described above, with the counter punch disposed at the lower side fixed, the pressing punch disposed at the upper side is pressed against the counter punch to form the intermediate molded product 15. The material is moved to fill the cavity surrounded by the inner peripheral surface of the die and the outer peripheral surface of the pressing punch and the counter punch.

  Here, in the upper annular body 22 which becomes the hub wheel, a large portion of the material from which the bottom portion 27 of the circular recess 20 is pushed out has a diameter passing through the lower end of the portion which is to be the outer rolling surface on the inner side of the hub The material flowing in the direction outward and having a low degree of cleanliness near the center becomes a flange portion 21. Therefore, in this finishing step, a large amount of material of the highly clean intermediate cylindrical portion exists in the portion where the double row outer raceway is formed.

  Further, in the lower annular body 23 serving as the inward member, a large portion of the material from which the bottom portion 27 of the circular recess 20 is pushed out passes radially through the upper end of the portion to be the inner rolling surface of the inward member. The material flows toward the center and has a low degree of cleanliness, and the material of the near-centered cylindrical portion becomes the outer diameter portion. Therefore, in the finishing process, a large amount of material of the highly clean intermediate cylindrical portion is present in the portion where the inner rolling surface of the inner member is formed.

  Thus, for example, the parent and child forging 24 molded at a hot temperature equal to or higher than the transformation point temperature is cooled at a predetermined cooling rate by furnace cooling, and a finished formed article to which an annealing treatment is applied is obtained. Since the parent and child forgings 24 have already been heated to the hot temperature by hot forging, there is no need to heat them again, and the annealing can be performed efficiently. That is, in the finish forming step, for example, the temperature is set to 500 ° C. lower than the temperature at the time of the hot forging step, cooling is performed at a cooling setting temperature and a cooling rate of time, and rigidity and ductility are achieved. The result is an improved finished product with a composition suitable for cold forging. The parent and child forged product 24 is maintained at a temperature around the so-called AC1 transformation temperature for a predetermined time when austenite starts to be formed during heating, and is cooled (leaved) to normal temperature at a cooling setting temperature and a cooling rate for time. good.

  Next, the oxide scale generated on the surface of the finished molded product is removed by hot forging, and the surface is smoothed by the shot blasting shown in (f) in the surface removing step where the surface is smoothed. And the altered portion (oxidized scale portion) is appropriately removed, and as shown in (g), the upper annular body 22 and the lower annular body 23 of the finished formed product (parent and forged product) 24 are separated by forging, It is sent to processing.

  Here, in a state where the support punch is inserted into the through hole 26 of the lower annular body 23, the separate (punching) punch presses almost the entire surface of the bottom portion 27 of the circular recess 20 of the upper annular body 22, And the lower annular body 23 are sheared. That is, as shown in the enlarged view of (h), even if the pressure from the separate punch is applied to the lower annular body 23, since the inside of the through hole 26 located inside these is restrained by the support punch, the lower portion The annular body 23 becomes difficult to deform. As a result, only the shear force along the lowering direction of the separate punch is applied to the sheared surface 23a (shown by cross hatching) in the lower annular body 23, and it becomes possible to separate the both accurately and efficiently.

  In the method of manufacturing the hub wheel and the inward member of the bearing device for a wheel according to the present invention, the upper annular body 22 serving as the hub wheel and the lower annular body 23 serving as the inward member are formed into tower-type parent and child forgings 24 After that, the surface is smoothed in the surface removing step, the altered portion is removed, and the upper annular body 22 and the lower annular body 23 are forged and separated, so that the conventional outer member and inner member are forged separately. In the method of the present invention, the partition wall portion (punched portion) which has been punched and discarded after forging of the outer member in the method is effectively utilized as a material of the inner member as it is to improve yield and reduce material input amount. Accordingly, it is possible to provide a method of manufacturing a hub ring and an inner member of a bearing device for a wheel, in which the reduction in life due to the influence of inclusions is reduced and the strength is improved.

  Thereafter, prior to the cold forging step, the surface of the finished formed article 24 is coated with a phosphate coating as a lubricant for reducing friction with the die in cold forging.

  Next, as shown in FIGS. 3 and 4, the separated upper annular body 22 is cold forged, and the upper annular body 22 and the lower annular body 23 are sent to the assembly process through a turning process. Specifically, as shown in FIG. 3 (a), the upper annular body 22 and the lower annular body 23 are separated by forging, and as shown in (b), the upper annular body 22 is cold forged (cold roll It forms by forming). In FIG. 3A, the shape of the cold forged product 28 of the upper annular body 22 and the shape of the lower annular body 23 to be separated are shown by a two-dot chain line. Since the formed shape of the cold forged product 28 in FIG. 3 (b) is formed to a shape almost similar to the final forged formed product, the cutting margin of the cutting process in the post process is simplified with the strength increase by work hardening. Can be That is, the flange portion 29, the outer row rolling surfaces 30, 31 of the double row, the inner diameter portion 32 serving as a pilot portion such as a wheel and a brake rotor, and the fitting portion 11a of the seal are cut by 0.5 mm or more and 1.5 mm or less It is formed into a cold forged product 28 leaving a turning allowance.

  Next, as shown in (c), the flange portion 29 of the cold forged product 28, the outer row rolling surfaces 30, 31 and the inner diameter portion 32 of the double row, and the fitting portion 11a of the seal are cut by turning, The machined product 33 is formed with the flange 8 and the inner diameter portion 2c, the fitting portion 11b, and the double row outer raceway surfaces 34 and 35 leaving a predetermined grinding allowance. Here, an insertion hole 8b in which a hub bolt (not shown) is pressed into the wheel mounting flange 8 is punched out by forging. The wheel mounting flange 8 may be drilled or drill reamed with a hub bolt insertion hole 8b.

  Next, as shown in (d), the double row outer raceway surfaces 34, 35 and the fitting portion 11a of the seal are hardened layers 36, 36 having a surface hardness of 58 HRC or more and 64 HRC or less by hardening and tempering by high frequency heat treatment. (Shown by cross hatching) is formed. The depth of the hardened layer 36 is set to 0.5 mm or more and 4 mm or less, as enlarged in (e). Thereby, the rolling fatigue life of the outer raceway surfaces 34, 35 can be secured. Finally, the multi-row outer raceway surface 34, 35 of (f) and the fitting portion 11a of the seal are sent to the assembly process through a grinding process consisting of grinding and superfinishing.

  As shown in FIG. 4 (a), the upper annular body 22 and the lower annular body 23 are separated by forging, and as shown in FIG. 4 (b), the widthwise surface and the outer peripheral surface of the lower annular body 23 are turned. The workpiece 39 is formed into a machined product 39 having a shaft-like portion 37 and an inner raceway surface 38, which are cut by machining and have a small diameter step portion leaving a predetermined grinding allowance. In FIG. 4A, the shape of the machined product 39 of the lower annular body 23 to be separated and the shape of the upper annular body 22 are indicated by two-dot chain lines.

  Next, as shown in (c), the shaft-like portion 37 and the inner raceway surface 38 are hardened to a surface hardness of 50 HRC or more and 64 HRC or less by hardening and tempering by induction heat treatment. The hardened layer 40 (shown by cross hatching) is set to have a hardened layer depth of 0.5 mm or more and 4 mm or less, as enlarged in (d). Thus, the fretting resistance of the shaft-like portion 37 serving as the fitting portion of the second inner ring member 5 can be improved, and the rolling fatigue life of the inner raceway surface 38 can be secured. Finally, the inner raceway surface 38 of (e) is sent to the assembly process through a grinding process consisting of grinding and superfinishing.

  Returning to FIG. 1, in the present embodiment, the second inner ring member 5 constituting the inner member 1 is formed through a hot forging process, a cutting process, a heat treatment process, and a grinding process, though not shown. After press-fitting the second inner ring member 5 into the small diameter step 4b of the first inner ring member 4, the second inner ring is formed by a crimped portion 4c formed by plastic deformation (rolling caulking) of the end of the small diameter step 4b. The member 5 is axially fixed.

  FIG. 5 is a longitudinal sectional view showing a second embodiment of the bearing device for a wheel according to the present invention, and FIGS. 6 (a) to 6 (h) are front views related to the method of manufacturing the hub wheel and inner member of FIG. FIGS. 7 (a) to 7 (f) are process diagrams showing subsequent steps according to the method of manufacturing the hub ring of FIG. 5, and FIGS. 8 (a) to 8 (e) are inwards of FIG. It is process drawing which shows the back process concerning the manufacturing method of a member. The same parts as the embodiment described above, or parts or parts having the same functions as those in the embodiment described above are designated by the same reference numerals and their detailed description will be omitted.

  The wheel bearing device shown in FIG. 5 is for a driven wheel referred to as the third generation, and includes an inner member 41 serving as a fixed side member, a hub ring (outer member) 42 serving as a rotating side member, and both It comprises double rows of rolling elements 3 and 3 accommodated rotatably between members 41 and 42. The inward member 41 includes an inner ring member 43 and an inner ring 44 press-fitted to the inner ring member 43 via a predetermined distance.

  The inner ring member 43 is formed with an inner raceway surface 43a on one side (inner side) and a small diameter step 43b axially extending from the inner raceway 43a via a step 43c. The inner ring 44 has the other (outer side) inner raceway surface 44a formed on the outer periphery, and is pressed into the small diameter step 43b of the inner ring member 43 and plastically deformed the end of the small diameter step 43b. It is axially fixed by the clamping portion 43f. The inner ring 44 is formed of high carbon chromium steel such as SUJ 2 and hardened to a core portion in the range of 58 to 64 HRC by squib hardening.

  The inner ring member 43 is formed of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the surface hardness is increased by induction hardening from the inner raceway surface 43a to the outer peripheral surface of the small diameter step portion 43b. It is hardened in the range of ~ 64 HRC. As a result, the fretting resistance of the small diameter step portion 43b which is the fitting portion of the inner ring 44 is improved, and the occurrence of a minute crack and the like can be prevented, and the plastic working of the crimped portion 43f can be smoothly performed.

  The hub wheel 42 integrally has a wheel mounting flange 8 at an end on the outer side, and hub bolts 8 a are planted at equal intervals in the circumferential direction of the wheel mounting flange 8. A thick rib 8 c is formed around the hub bolt 8 a of the wheel mounting flange 8. The rib 8c can reduce the weight and the rigidity of the hub wheel 42, and can ensure sufficient strength even if a large bending moment load is applied to the wheel mounting flange 8.

  Further, on the inner periphery of the hub wheel 42, the outer raceway surface 2a on the outer side facing the inner raceway surface 44a of the inner ring 44, and the inner race member 43 from the outer raceway surface 2a via the step 42a. The outer side rolling surface 2b of the inner side which opposes the rolling surface 43a is integrally formed. A double row of rolling elements 3, 3 is accommodated between the two rolling surfaces, and is held by the cages 9, 10 so as to be rollable. This hub ring 42 is formed of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and at least double row outer raceway surfaces 2a and 2b have surface hardness in the range of 58 to 64 HRC by induction hardening. It has been hardened.

  The outer shape of the inner ring member 43 is from the groove bottom of the inner raceway surface 43a to the counter portion 43d, the step portion 43c formed to be inclined from the counter portion 43d, and the shoulder portion 43e against which the inner ring 44 abuts It follows the small diameter step 43b. On the other hand, in the hub wheel 42, the outer raceway surface 2b on the inner side is formed larger in diameter than the outer raceway surface 2a on the outer side according to the difference in pitch circle diameters PCDi and PCDo. An outer side rolling surface 2b on the inner side is formed via a step 42a inclined from the surface 2a. The inclination angle of the step 42 a is set to be substantially the same as the inclination angle of the step 43 c of the inner ring member 43.

  In the wheel bearing device having such a configuration, the pitch circle diameter PCDi of the rolling elements 3 on the inner side is set larger than the pitch circle diameter PCDo of the rolling elements 3 on the outer side, and the number of rolling elements 3 is also correspondingly Since the number on the inner side is set larger than the number on the outer side, bearing rigidity can be effectively utilized to increase the bearing rigidity of the inner side portion as compared to the outer side, thereby achieving longer life of the bearing. be able to. Furthermore, since the inclinations of the step 43c of the inner ring member 43 and the step 42a of the hub wheel 42 are set to be substantially the same angle, the contradictory problems of lightening and compacting of the device and high rigidity can be solved. it can.

  At the inner end of the inner ring member 43, a mounting portion 46 having a conical recess 45 is formed. The depth of the recess 45 is up to the vicinity of the shoulder 43e, and the inner end of the inner ring member 43 has a substantially uniform thickness. Thereby, weight reduction can be achieved while maintaining the strength of the inner ring member 43. In the present embodiment, a plurality of bolt holes 46a are formed in the mounting portion 46, and the mounting portion 46 is attached to a knuckle (not shown) constituting a suspension system by fixing bolts 47 fastened to the bolt holes 46a.

  Further, since the outer side rolling surface 2b on the inner side is formed larger in diameter than the outer rolling surface 2a on the outer side, the outer shape of the hub wheel 42 is formed at the base on the inner side of the wheel mounting flange 8. A tapered surface 42c whose diameter gradually increases toward the inner side from the annular concave portion 42b having an arc-shaped cross section, and a cylindrical outer peripheral surface 42d which is an outer diameter side of the outer rolling surface 2b on the inner side from the tapered surface 42c. It is configured. By forming the annular recess 42b, the hub bolt 8a for fixing the wheel can be easily attached and detached, the work efficiency in the manufacturing process can be improved, and the repair work in the market can be simplified.

  Here, in the present embodiment, as in the first embodiment described above, the hub wheel and the inward member (inner ring member) are formed by parent-child hot forging, but FIGS. 6 (a) to 6 (c) Since the process is the same as the process described above, the description thereof is omitted.

  Therefore, in the upsetting process shown in FIG. 6 (d), the pressing punch and the counter which are disposed concentrically with each other in a state where they are set in a die whose concavity and convexity are reversed corresponding to the outer peripheral surface shape of the intermediate molded product 48. The middle portions of both end faces in the axial direction of the roughly shaped product 14 are pressed between the punches, and the material in the radially central portion is moved in the axial direction while being moved radially outward, and the intermediate formed product 48 is formed. Molding. Here, with the counter punch disposed at the lower side fixed, the pressing punch disposed at the upper side is pressed against the counter punch. Then, the material of the roughly shaped product 14 is moved to fill the cavity surrounded by the inner peripheral surface of the die and the outer peripheral surface of the pressing punch and the counter punch, and a circular opening in one axial end surface side (upper part) It is formed into a shaft-like portion 50 having a recess 49, a flange portion 17 serving as a wheel mounting flange portion, and a circular recess 18 opened on the other end surface side (lower portion) in the axial direction. The axial portion 50 of the intermediate molded product 48 is an inner ring member.

  Next, in the finish forming step shown in (e), while increasing the depth of the circular recess 49 of the intermediate molded product 48, the diameter of the inner peripheral surface is increased to form an upper annular body having the circular recess 51 and the flange portion 52 ( It is formed into a tower type parent-child forging 55 which is connected to the parent member 53 and the upper end of the lower annular body (child member) 54 at the lower inside diameter of the upper annular body 53 and further at the bottom of the lower annular body 54. Be done. At the same time, the shaft-like portion 50 of the intermediate molded product 48 is pushed out in the axial direction, and the outer circumferential surface is formed into the lower annular body 54 having the shaft-like portion 56 which becomes the inner rolling surface of the inward member. In this finishing step, as in the setting step (d) described above, with the counter punch disposed at the lower side fixed, the pressing punch disposed at the upper side is pressed against the counter punch to form the intermediate molded product 48. The material is moved to fill the cavity surrounded by the inner peripheral surface of the die and the outer peripheral surface of the pressing punch and the counter punch.

  Here, in the upper annular body 53 to be the hub wheel, a large portion of the material from which the opening end 51a of the circular recess 51 is pushed out passes through the upper end of the portion that is to be the outer rolling surface on the inner side of the hub wheel. The material flows radially outward, and the material of the less central portion near the center becomes the flange portion 52. Therefore, in this finishing step, a large amount of material of the highly clean intermediate cylindrical portion exists in the portion where the double row outer raceway is formed.

  Further, in the lower annular body 54 to be the inward member, a large portion of the material from which the bottom portion 51b of the circular recess 51 is pushed out passes the lower end of the portion to be the inner rolling surface of the inward member The material flows toward the center and has a low degree of cleanliness, and the material of the near-centered cylindrical portion becomes the outer diameter portion. Therefore, in the finishing process, a large amount of material of the highly clean intermediate cylindrical portion is present in the portion where the inner rolling surface of the inner member is formed.

  Next, the oxide scale generated on the surface of the finished molded product is removed by hot forging, and the surface is smoothed by the shot blasting shown in (f) in the surface removing step where the surface is smoothed. And the degraded portion (oxidized scale portion) is appropriately removed, and as shown in (g), the upper annular body 53 and the lower annular body 54 of the finished formed product (parent and forged product) 55 are cut and separated. It is sent to processing.

  Here, as shown in the enlarged view of (h), since the connecting portion of the upper annular body 53 and the lower annular body 54 is a cut surface 54a (shown by cross hatching), it is necessary to separate both accurately and efficiently. Is possible.

  In the method of manufacturing the hub wheel and the inward member of the bearing device for a wheel according to the present invention, the upper annular body 53 serving as the hub wheel and the lower annular body 54 serving as the inward member are formed into a tower-type parent and child forging 55 Thereafter, the surface is smoothed in the surface removing step, the altered portion is removed, and the upper annular body 53 and the lower annular body 54 are cut and separated, so that the conventional outer member and inner member are separately forged. In the method of the present invention, the partition wall portion (punched portion) which has been punched and discarded after forging of the outer member in the method is effectively utilized as a material of the inner member as it is to improve yield and reduce material input amount. Accordingly, it is possible to provide a method of manufacturing a hub ring and an inner member of a bearing device for a wheel, in which the reduction in life due to the influence of inclusions is reduced and the strength is improved.

  Thereafter, prior to the cold forging step, the surface of the finished molded article 55 is coated with a phosphate coating as a lubricant to reduce friction with the die in cold forging.

  Next, as shown in FIGS. 7 and 8, the separated upper annular body 53 is cold forged, and the upper annular body 53 and the lower annular body 54 are sent to the assembly process through a turning process. Specifically, as shown in FIG. 7A, the upper annular body 53 and the lower annular body 54 are cut and separated, and as shown in FIG. 7B, the upper annular body 53 is cold forged (cold roll It forms by forming). In FIG. 7A, the shape of the lower annular body 54 to be separated is shown by a two-dot chain line. The formed shape of the cold forged product 57 is formed almost to a shape close to the final forged product. That is, the flange portion 58, the outer raceway surfaces 59, 60 of the double row, the inner diameter portion 32 serving as a pilot portion such as a wheel and a brake rotor, and the fitting portion 11a of the seal are cut by 0.5 mm or more and 1.5 mm or less It is formed into a cold forged product 57 leaving a turning allowance.

  Next, as shown in (c), the width surface of the cold forged product 57, the flange portion 58, the double row outer raceway surfaces 59, 60 and the inner diameter portion 32 and the fitting portion 11a of the seal are cut by turning. Thus, it is formed into a machined product 63 having a width surface, the wheel mounting flange 8 and the inner diameter portion 2c and the fitting portion 11a, and double rows of outer raceway surfaces 61 and 62 with a predetermined grinding allowance left. Here, an insertion hole 8b in which a hub bolt (not shown) is pressed into the wheel mounting flange 8 is punched out by forging. The wheel mounting flange 8 may be drilled or drilled and reamed with a hub bolt insertion hole 8b.

  Next, as shown in (d), the outer row rolling surfaces 61, 62 and the fitting portion 11a of the seal are hardened layers 36, 36 having a surface hardness of 58 HRC or more and 64 HRC or less due to quenching and tempering by high frequency heat treatment. (Shown by cross hatching) is formed. The depth of the hardened layer 36 is set to 0.5 mm or more and 4 mm or less, as enlarged in (e). Thereby, the rolling fatigue life of the outer raceway surfaces 61 and 62 can be secured. Finally, the multi-row outer raceway surfaces 61, 62 of (f) and the fitting portion 11a of the seal are sent to the assembly process through a grinding process including grinding and superfinishing.

  As shown in FIG. 8 (a), the upper annular body 53 and the lower annular body 54 are cut and separated, and as shown in FIG. 8 (b), the width surface and the outer peripheral surface of the lower annular body 54 are turned. It is formed into a machined product 66 having a shaft-like portion 64 which is cut by machining and has a small diameter step portion leaving a predetermined grinding allowance and an inner raceway surface 65, and a female screw 46a is tapped in the mounting portion 46 Ru. In FIG. 8A, the shape of the upper annular body 53 to be separated is shown by a two-dot chain line.

  Next, as shown in (c), the shaft-like portion 64 and the inner raceway surface 65 are hardened to a surface hardness of 50 HRC or more and 64 HRC or less by hardening and tempering by high frequency heat treatment. The hardened layer 40 (shown by cross hatching) is set to have a hardened layer depth of 0.5 mm or more and 4 mm or less, as enlarged in (d). As a result, the fretting resistance of the shaft-like portion 64 which is the fitting portion of the inner ring is improved, and the rolling fatigue life of the inner raceway surface 65 can be secured. Finally, the inner raceway surface 65 of (e) is sent to the assembly process through a grinding process consisting of grinding and superfinishing.

  Referring back to FIG. 5, in the present embodiment, the inner ring 44 constituting the inner member 41 is formed through a hot forging step, a cutting step, a heat treatment step and a grinding step, though not shown. After press-fitting the small diameter step portion 43b of the member 43, the inner ring 44 is axially fixed by a crimped portion 43f formed by plastic deformation (rolling caulking) of the end of the small diameter step portion 43b.

  FIG. 9 is a longitudinal sectional view showing a third embodiment of the bearing device for a wheel according to the present invention, and FIGS. 10 (a) to 10 (h) are front views related to the method of manufacturing the hub wheel and inner member of FIG. FIGS. 11 (a) to 11 (e) are process diagrams showing the subsequent steps of the method for manufacturing the hub ring of FIG. 9, and FIGS. 12 (a) to 12 (f) are diagrams of the inner ring of FIG. It is process drawing which shows the post process which concerns on a manufacturing method. The same parts as the embodiment described above, or parts or parts having the same functions as those in the embodiment described above are designated by the same reference numerals and their detailed description will be omitted.

  The wheel bearing device shown in FIG. 9 is for a driven wheel referred to as the third generation, and includes an inner member 67 as a stationary member, a hub ring (outer member) 68 as a rotary member, and both of them. It comprises double rows of rolling elements 3, 3 accommodated rotatably between members 67, 68. The inner member 67 includes an inner ring member 69 and an inner ring 44 which is press-fitted to the inner ring member 69 via a predetermined distance.

  The inner ring member 69 is formed with an inner rolling surface 4a on one side (inner side) and a cylindrical small diameter step 4b axially extending from the inner rolling surface 4a. The inner race 44 has the other (outer side) inner raceway surface 44 a formed on the outer periphery thereof and is press-fitted and fixed to the small diameter step 4 b of the inner race member 69. The inner ring member 69 is formed of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the surface hardness is increased by induction hardening from the inner raceway surface 4a to the outer peripheral surface of the small diameter step 4b. It is hardened in the range of ~ 64 HRC.

  The hub wheel 68 integrally has a wheel mounting flange 8 at the end on the outer side, and on the inner periphery, the outer side rolling surface 2a facing the inner rolling surface 4a of the inner ring member 69, and the inner ring member The outer side rolling surface 2a of the inner side which opposes 44 the inner side rolling surface 44a is integrally formed. A double row of rolling elements 3, 3 is accommodated between the two rolling surfaces, and is held by the cages 9, 9 in a freely rolling manner. This hub ring 68 is formed of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and at least double row outer raceway surfaces 2a, 2a have surface hardness in the range of 58 to 64 HRC by induction hardening It has been hardened.

  Here, in the present embodiment, as in the second embodiment described above, the hub ring and the inward member (inner ring) are formed by parent-child hot forging, with regard to FIGS. 10 (a) to (c). Since the process is the same as the process described above, the description thereof is omitted.

  Therefore, in the upsetting process shown in FIG. 10 (d), the pressing punch and the counter which are disposed concentrically with each other in a state where they are set in a die whose concavity and convexity are reversed corresponding to the outer peripheral surface shape of the intermediate molded product 70. Between the punches, the central portions of both axial end faces of the roughly shaped product 14 are pressed, and the material of the radially central portion is moved radially outward while being moved radially outward, and the intermediate molded product 70 is formed. Molding. Here, with the counter punch disposed at the lower side fixed, the pressing punch disposed at the upper side is pressed against the counter punch. Then, the material of the roughly shaped product 14 is moved to fill the cavity surrounded by the inner peripheral surface of the die and the outer peripheral surface of the pressing punch and the counter punch, and a circular opening in one axial end surface side (upper part) It is formed into a shaft-like portion 72 having a concave portion 71, a flange portion 17 to be a wheel mounting flange portion, and a circular concave portion 18 opened on the other axial end surface side (lower portion). The shaft-like portion 72 of the intermediate molded product 70 is an inner ring member.

  Next, in the finish forming step shown in (e), while increasing the depth of the circular recess 71 of the intermediate molded product 70, the diameter of the inner peripheral surface is increased to form an upper annular body having a circular recess 73 and a flange 52 A parent member 74 and a tower type parent-child forging 76 connected to the lower inner diameter of the upper annular member 74 at the upper end of the lower annular member (child member) 75 are formed. Further, at the same time, the shaft-like portion 72 of the intermediate molded product 70 is pushed out in the axial direction, and the outer circumferential surface becomes the inner rolling surface of the inward member. An annular body 75 is formed. In this finishing step, as in the setting step (d) described above, with the counter punch disposed on the lower side fixed, the pressing punch disposed on the upper side is pressed against the counter punch to form the intermediate molded product 70. The material is moved to fill the cavity surrounded by the inner peripheral surface of the die and the outer peripheral surface of the pressing punch and the counter punch.

  Here, in the upper annular body 74 to be the hub wheel, a large portion of the material from which the open end 51a of the circular recess 73 is pushed out passes through the upper end of the portion that is to be the outer rolling surface on the inner side of the hub wheel. The material flows radially outward, and the material of the less central portion near the center becomes the flange portion 52. Therefore, in this finishing step, a large amount of material of the highly clean intermediate cylindrical portion exists in the portion where the double row outer raceway is formed.

  Further, in the lower annular body 75 serving as the inner member (inner ring), a portion of the material from which the bottom portion 71b of the circular recess 71 of the intermediate molded product 70 is pushed out should be the inner raceway surface of the inner member. The material flows radially outward through the lower end of the lower portion, and the material of the less central portion near the center becomes the outer diameter portion. Therefore, in the finishing process, a large amount of material of the highly clean intermediate cylindrical portion is present in the portion where the inner rolling surface of the inner member is formed.

  Next, the oxide scale generated on the surface of the finished molded product is removed by hot forging, and the surface is smoothed by the shot blasting shown in (f) in the surface removing step where the surface is smoothed. And the degraded portion (oxidized scale portion) is appropriately removed, and as shown in (g), the upper annular body 74 and the lower annular body 75 of the finished formed product (parent and forged product) 76 are separated by forging. It is sent to processing. Here, as shown in the enlarged view of (h), since the connection portion between the upper annular body 74 and the lower annular body 75 is a slight shear surface 75a, it is possible to separate the both accurately and efficiently.

  In the method of manufacturing the hub wheel and the inward member of the bearing device for a wheel according to the present invention, the upper annular body 74 serving as the hub wheel and the lower annular body 75 serving as the inward member are formed into tower-type parent and child forgings 76, After that, the surface is smoothed in the surface removing step, the altered portion is removed, and the upper annular body 74 and the lower annular body 75 are separated by forging, so that the conventional outer member and the inner member are separately forged. In the method of the present invention, the partition wall portion (punched portion) which has been punched and discarded after forging of the outer member in the method is effectively utilized as a material of the inner member as it is to improve yield and reduce material input amount. Accordingly, it is possible to provide a method of manufacturing a hub ring and an inner member of a bearing device for a wheel, in which the reduction in life due to the influence of inclusions is reduced and the strength is improved.

  Next, as shown in FIGS. 11 and 12, the separated upper annular body 74 and lower annular body 75 are sent to the assembly process through a turning process and cold forging (cold roll forming), respectively. Specifically, as shown in FIG. 11A, the upper annular body 74 and the lower annular body 75 are separated by forging, and as shown in FIG. 11B, the width surface of the upper annular body 74 and the flange portion 52 are circular. A machined product 78 having a recess 73 cut by turning and having a width surface as well as the wheel mounting flange 8 and the inner diameter portion 2c and the fitting portion 11a, and double rows of outer raceway surfaces 2a and 2a leaving a predetermined grinding allowance. Is formed. Here, an insertion hole 8b in which a hub bolt (not shown) is pressed into the wheel mounting flange 8 is punched out by forging. The wheel mounting flange 8 may be drilled or drilled and reamed with a hub bolt insertion hole 8b.

  Next, as shown in (c), the outer raceway surfaces 2a, 2a of the double row and the fitting portion 11a of the seal are hardened layers 36, 36 having a surface hardness of 58 HRC or more and 64 HRC or less by hardening and tempering by high frequency heat treatment. (Shown by cross hatching) is formed. The depth of the hardened layer 36 is set to 0.5 mm or more and 4 mm or less, as shown in the enlarged view of (d). Thereby, the rolling fatigue life of outer side rolling surfaces 2a and 2a is securable. Finally, the double row of outer raceway surfaces 2a and 2a of (e) and the fitting portion 11a of the seal are subjected to a grinding process including grinding and superfinishing, and are sent to the assembly process.

  As shown in FIG. 12 (a), the upper annular body 74 and the lower annular body 75 are separated by forging, and as shown in (b), the inner raceway surface 79 and the inner diameter surface 80 of the lower annular body 75 are cold. A machined product 83 which is formed by forging (cold roll forming) and then has a width surface, an inner raceway surface 81 and an inner diameter surface 82 with a predetermined grinding allowance left as shown in (c). Is formed. In FIG. 12A, the shape of the upper annular body 74 to be separated by forging is indicated by a two-dot chain line.

  Next, as shown in (d), the inner raceway surface 81 and the inner diameter surface 82 including the width surface are hardened to a surface hardness of 58 HRC or more and 64 HRC or less by hardening and tempering by induction heat treatment. The hardened layer 40 (shown by cross hatching) is set to have a hardened layer depth of 0.5 mm or more and 4 mm or less, as enlarged and shown in (e). Thereby, the rolling fatigue life of the inner raceway surface 81 can be secured. Finally, the inner diameter surface 82 including the width surface of (f) is ground, and the inner raceway surface 81 is sent to the assembly process through a grinding process including grinding and superfinishing.

  FIG. 13 is a longitudinal sectional view showing a fourth embodiment of a bearing device for a wheel according to the present invention, and FIGS. 14 (a) to 14 (h) are front views related to a method of manufacturing a hub ring and an inner member of FIG. FIG. 15 (a) to FIG. 15 (e) are process diagrams showing the subsequent steps of the method for manufacturing the hub ring of FIG. 13, and FIGS. 16 (a) to 16 (f) are steps of the inner ring of FIG. FIGS. 17 (a) to 17 (f) are process diagrams showing a rear process related to the manufacturing method of the inner ring member of FIG. The same parts as the embodiment described above, or parts or parts having the same functions as those in the embodiment described above are designated by the same reference numerals and their detailed description will be omitted.

  The wheel bearing device shown in FIG. 13 is for a driven wheel referred to as the third generation, and includes an inward member 84 serving as a stationary member, a hub ring (outward member) 85 serving as a rotating member, and both of them. It comprises double rows of rolling elements 3, 3 accommodated rotatably between members 84, 85. The inward member 84 includes an inner ring member 86 and an inner ring 44 press-fitted to the inner ring member 86 via a predetermined distance.

  The inner ring member 86 has an outer peripheral rolling surface 86a on one side (inner side), a cylindrical small diameter stepped portion 86b axially extending from the inner rolling surface 86a, and an outer diameter side of the inner rolling surface 86a. A radially outwardly extending vehicle mounting flange 6 is integrally formed. The inner ring 44 has the other (outer side) inner raceway surface 44a formed on the outer periphery, and is press-fitted into the small diameter step 86b of the inner ring member 86, and plastically deforms the end of the small diameter step 86b radially outward. It is axially fixed by the caulking part 86c formed. The inner ring member 86 is formed of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and has a surface hardness of 50 by induction hardening from the inner raceway surface 86a to the outer peripheral surface of the small diameter step 86b. It is hardened in the range of ~ 64 HRC.

  The hub wheel 85 integrally has a wheel mounting flange 8 at the end on the outer side, and the outer side rolling surface 2 a on the outer side facing the inner rolling surface 44 a of the inner ring 44 on the inner periphery and the inner side of the inner ring member 86. The outer side rolling surface 85a of the outer side which opposes the rolling surface 86a is integrally formed. A double row of rolling elements 3 and 3 is accommodated between the two rolling surfaces, and is held rollably by cages 9 and 87. This hub ring 85 is formed of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and at least double row outer raceway surfaces 2a and 85a have surface hardness in the range of 58 to 64 HRC by induction hardening. It has been hardened.

  In the present embodiment, the pitch circle diameter PCDo of the rolling element 3 on the outer side is set larger than the pitch circle diameter PCDi of the rolling element 3 on the inner side. And although the size of the double row rolling elements 3 is the same, the number of rolling elements 3 on the outer side is set larger than the number of rolling elements 3 on the inner side due to the difference between the pitch circle diameters PCDo and PCDi. ing. As a result, the bearing rigidity 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 prolonged.

  Here, in the present embodiment, as in the third embodiment described above, the hub wheel and the inward member are formed by hot forging parent-child forging, but as described above with reference to FIGS. 14 (a) to (c) Since the process is the same as the process, the description thereof is omitted.

  Therefore, in the upsetting process shown in FIG. 14 (d), the pressing punch and the counter which are disposed concentrically with each other in a state where they are set in a die whose concavity and convexity are reversed corresponding to the outer peripheral surface shape of the intermediate molded product 88. Between the punches, the central portions of both end faces in the axial direction of the roughly shaped article 14 are pressed, and the material in the radially central portion is moved radially outward while being moved radially outward, and the intermediate formed article 88 Molding. Here, with the counter punch disposed at the lower side fixed, the pressing punch disposed at the upper side is pressed against the counter punch. Then, the material of the roughly shaped product 14 is moved to fill the cavity surrounded by the inner peripheral surface of the die and the outer peripheral surface of the pressing punch and the counter punch, and a circular opening in one axial end surface side (upper part) It is formed into a shaft-like portion 90 having a recess 89, a flange portion 17 to be a wheel mounting flange portion, and a circular recess 18 opened on the other end surface side (lower portion) in the axial direction. The axial portion 90 of the intermediate molded product 88 is an inner member (inner ring member and inner ring).

  Next, in the finish forming step shown in (e), while increasing the depth of the circular recess 89 of the intermediate molded product 88, the diameter of the inner peripheral surface is increased to form an upper annular body having a circular recess 91 and a flange portion 52 ( A parent member 92 and a tower type parent-child forging 94 connected to the lower inside diameter of the upper annular body 92 at the upper end of the lower annular body 93 are formed. At the same time, the lower ring-shaped body having the through hole 26 by punching out the shaft-like portion 93a to be the inner ring, the shaft-like portion 93b to be the inner ring member and the circular recess 18 It is molded to 93. In this finishing step, as in the setting step (d) described above, with the counter punch disposed at the lower side fixed, the pressing punch disposed at the upper side is pressed against the counter punch to form the intermediate molded product 88. The material is moved to fill the cavity surrounded by the inner peripheral surface of the die and the outer peripheral surface of the pressing punch and the counter punch.

  Here, in the upper annular body 92 to be the hub wheel, a large portion of the material from which the open end 51a of the circular recess 91 is pushed out passes through the upper end of the portion to be the outer rolling surface on the inner side of the hub wheel. The material flows radially outward, and the material of the less central portion near the center becomes the flange portion 52. Therefore, in this finishing step, a large amount of material of the highly clean intermediate cylindrical portion exists in the portion where the double row outer raceway is formed.

  Further, in the lower annular body 93 serving as the inward member, the lower end of the portion where a large portion of the material from which the bottom 89a of the circular recess 71 of the intermediate molded product 88 is pushed out becomes the inner rolling surface of the inward member The material flows radially outward, and the material of the less central portion near the center becomes the outer diameter portion. Therefore, in the finishing process, a large amount of material of the highly clean intermediate cylindrical portion is present in the portion where the inner rolling surface of the inner member is formed.

  Next, the oxide scale generated on the surface of the finished molded product is removed by hot forging, and the surface is smoothed by the shot blasting shown in (f) in the surface removing step where the surface is smoothed. And the altered portion (oxidized scale portion) is appropriately removed, and as shown in (g), the upper annular body 92 and the lower annular body 93 of the finished formed product (parent and forged product) 94 are forged and separated, It is sent to processing. Here, as shown in the enlarged view of (h), the connection portion between the upper annular body 92 and the shaft-like portion 93a becomes a slight shear surface 75a, and the connection portion between the shaft-like portion 93a and the shaft-like portion 93b is cut. Since the surface 93 c is provided, it is possible to separate the members accurately and efficiently.

  Next, as shown in FIGS. 15 to 17, the separated upper annular body 92 and lower annular body 93 are respectively sent to the assembly process through a turning process and cold forging (cold roll forming). Specifically, as shown in FIG. 15A, the upper annular body 92 and the lower annular body 93 are separated by forging, and as shown in FIG. 15B, the width surface of the upper annular body 92 and the flange portion 52 and the circular shape The recess 91 is cut by turning and is formed into a machined product 95 having the wheel mounting flange 8 and the inner diameter portion 2c and the fitting portion 11a, and double rows of outer raceway surfaces 95a and 95b leaving a predetermined grinding allowance. Ru. Here, an insertion hole 8b in which a hub bolt (not shown) is pressed into the wheel mounting flange 8 is punched out by forging. The wheel mounting flange 8 may be drilled or drilled and reamed with a hub bolt insertion hole 8b.

  Next, as shown in (c), the double row outer raceway surfaces 95a, 95b and the fitting portion 11a of the seal are hardened layers 36, 36 having surface hardness of 58 HRC or more and 64 HRC or less by hardening and tempering by high frequency heat treatment. (Shown by cross hatching) is formed. The depth of the hardened layer 36 is set to 0.5 mm or more and 4 mm or less, as shown in the enlarged view of (d). Thereby, the rolling fatigue life of outer side rolling surfaces 95a and 95b can be secured. Finally, the multi-row outer raceway surface 2a, 95b of (e) and the fitting portion 11a of the seal are sent to the assembly process through a grinding process consisting of grinding and superfinishing.

  As shown in FIG. 16 (a), the upper annular body 92 and the lower annular body 93 are separated by forging, and as shown in (b), the inner raceway surface 79 and the inner diameter of the shaft-like portion 93a of the lower annular body 93. The surface 80 is formed by cold forging (cold roll forming), and then, as shown in (c), with the predetermined grinding allowance left, the inner raceway surface 81 and the inner diameter surface 82 including the width surface are It forms in the cutting goods 83 which have.

  Next, as shown in (d), the inner raceway surface 81 and the inner diameter surface 82 including the width surface are hardened to a surface hardness of 58 HRC or more and 64 HRC or less by hardening and tempering by induction heat treatment. The hardened layer 40 (shown by cross hatching) is set to have a hardened layer depth of 0.5 mm or more and 4 mm or less, as enlarged and shown in (e). Thereby, the rolling fatigue life of the inner raceway surface 81 can be secured. Finally, the inner diameter surface 82 including the width surface of (f) is ground, and the inner raceway surface 81 is sent to the assembly process through a grinding process including grinding and superfinishing.

  On the other hand, as shown in FIG. 17 (a), the shaft-like portion 93a and the shaft-like portion 93b constituting the lower annular body 93 are cut and separated, and as shown in (b), the inner raceway of this shaft-like portion 93b The surface 96, the body mounting flange 97, and the small diameter step portion 98 are formed by cold forging (cold roll forming), and then, as shown in (c), with the predetermined grinding allowance left, including the width surface and the inside It is formed into a machined product 99 having a rolling surface 96a, a vehicle body mounting flange 6 and a small diameter step 98a. Here, the female screw 6b is formed after the lower hole of the female screw 6b in which the vehicle body mounting bolt (not shown) is screwed into the vehicle body mounting flange 6 is punched out by forging. The lower hole of the female screw 6b of the vehicle body mounting bolt may be drilled or drilled and reamed on the vehicle body mounting flange 6.

  Next, as shown in (d), the width surface and the inner raceway surface 96a and the small diameter step portion 98a are hardened to a surface hardness of 50 HRC or more and 64 HRC or less by hardening and tempering by high frequency heat treatment. The hardened layer 40 (shown by cross hatching) is set to have a hardened layer depth of 0.5 mm or more and 4 mm or less, as enlarged and shown in (e). Thereby, the rolling fatigue life of the inner raceway surface 96a can be secured. Finally, the small diameter step portion 98a including the width face of (f) is ground, and the inner raceway face 96a is sent to the assembly step through a grinding process including grinding and superfinishing.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way, and is merely an example, and various modifications can be made without departing from the scope of the present invention. The scope of the present invention is, of course, indicated by the description of the claims, and the meaning of equivalents described in the claims, and all modifications within the scope. Including.

  The hub wheel of the bearing device for a wheel according to the present invention has a wheel mounting flange integrally at one end, and one inner raceway surface on the outer periphery of a shaft portion protruding to the inner side from the base of the wheel mounting flange The present invention can be applied to a hub wheel of a bearing device for a wheel of a third generation structure in which a cylindrical small diameter step portion axially extending in the axial direction from an inner raceway surface via a shoulder portion is formed.

1, 41, 67, 84 Inner members 2, 42, 68, 85 Hub ring 2a, 2b, 30, 31, 34, 35, 59, 60, 61, 62, 76, 85a, 95a, 95b Outer raceway surface 2c, 32 Inner diameter portion 3 Rolling element 4 First inner ring member 4a, 5a, 38, 43a, 44a, 65, 79, 81, 86, 96, 96a Inner raceway surface 4b, 43b, 86b, 98, 98a Small diameter step Part 4c Crimping part 5 Second inner ring member 6, 97 Car body mounting flange 6a Base 6b on the outer side of car body mounting flange Female screw 7 Pilot part 8 Wheel mounting flange 8a Hub bolt 8b Insertion hole 8c Rib 9, 10, 87 Retainer 11 Seals 11a and 11b Seal fitting portion 12 Column-shaped steel material 13 Upset processed product 14 Rough shape product 14a Recess 14b Thick annular portion 14c, 19, 25, 37, 50, 56, 64, 2, 77, 93a, 93b Shaft-like portions 15, 48, 70 Intermediate molded products 16, 18, 20, 49, 51, 71, 73, 91 Circular recesses 17, 21, 29, 52, 58 Flanges 22, 53, 74, 92 upper annular body 23, 54, 75, 93 lower annular body 23a, 75a sheared surface 24, 55, 76, 94 parent and child forging 26 through hole 27 bottom of circular recess 28, 57 cold forging 33, 39, 63, 66, 78, 83, 95, 99 Cutting product 36, 40 Hardened layer 42a, 43c Step 42b Annular recess 42c Tapered surface 42d Outer peripheral surface 43 Inner ring member 43d Counter 43e Shoulder 44 Inner ring 45 Recessed 46 Attachment 46a bolt hole (female screw)
47 Fixing bolt 51a Opening end 51b of the circular recess Bottom 54a of the circular recess Cutting surface 80, 82 Inner diameter surface 101 Material 102 Front stage intermediate material 103 Metal material 104 Second front stage intermediate material 105, 106 Partition 107, 108 Circular recess 109 mounting portion 110 burr 111 outer member 111a outer raceway surface 112 preliminary post-stage intermediate material 113 post-stage intermediate material 114 metal material 115 final intermediate material 120 cylindrical steel material 121 upset workpiece 122 dish-shaped depression 123 preformed product 124 Upper thick annular body 125 Thick annular body 126 Bottom parts of thick annular body 129, 132, 133 Parent and child forgings 130, 134 Outer race raw form products 131, 135 Inner race raw form products PCDo Outer side rolling element pitch Circle diameter PCDi Inner diameter of rolling element pitch circle diameter

Claims (6)

A hub wheel integrally formed with a wheel mounting flange for mounting a wheel at an end on the outer side, and having a double row of outer race surfaces formed on the inner periphery;
An inward member in which an inner raceway surface facing the outer raceway surface of the double row is formed on the outer periphery respectively;
In a method of manufacturing a hub ring and an inner member of a bearing device for a wheel comprising the inward member and a double row of rolling elements rollably accommodated between both rolling surfaces of the hub wheel,
A cylindrical steel material is heated to a hot forming temperature and diameter-increased by upset processing between the upper mold and the lower mold to make upset products, and this upset processed product is an upper annular body and an inner diameter of the upper annular body The forging is formed into a tower type parent-child forging consisting of a lower annular body connected to the lower portion at the outer peripheral upper end portion, and the parent and forged product is separated into the upper annular body and the lower annular body. Finished products of parts ,
The upset processed product is forward extruded using a mold corresponding to the outer peripheral surface shape of the coarsely shaped product to obtain a roughly shaped product having a shallow dish-like concave portion at the top, a thick annular portion and a shaft-like portion. A rough forming process for forming;
Between the pressing punch and the counterpunch arranged concentrically with each other in a state of being set in a die whose concavity and convexity are reversed corresponding to the outer peripheral surface shape of the intermediate molded product, both axial end surfaces of the roughly shaped product The center portion of the die is pressed, and the material of the radially center portion is moved radially outward while being moved radially, and is surrounded by the inner peripheral surface of the die and the outer peripheral surfaces of the pressing punch and the counter punch. An intermediate forming step of forming a shaft-like portion filled with the circular cavity having a circular recess opening in the axial direction one end surface side, a flange portion serving as a wheel mounting flange portion, and a circular recess opening in the axial direction When,
The diameter of the inner peripheral surface is enlarged while forming the upper annular body while increasing the depth of the circular recess on one end side of the intermediate molded product, and at the same time, the axial portion of the intermediate molded product is extruded in the axial direction And a final forming step of punching out a circular recess on the other end side to form a lower annular body having a through hole. A manufacturing method of a hub ring and an inner member of a bearing device for a wheel. With the support punch inserted in the through hole of the lower annular body, the separate punch is pressed almost all over the bottom of the circular recess of the upper annular body to shear between the upper annular body and the lower annular body A method of manufacturing a hub ring and an inner member of a bearing device for a wheel according to claim 1 . The hub wheel of the bearing apparatus for a wheel according to claim 1, wherein the pitch circle diameter PCDo of the rolling elements on the outer side among the double row rolling elements is set smaller than the pitch circle diameter PCDi of the rolling elements on the inner side. And method of manufacturing the inner member.   The method for manufacturing a hub wheel and an inner member of a wheel bearing device according to claim 1, wherein the outer raceway surface of the double row of hub wheels is formed by cold forging after hot forging.   The inner member is an inner ring member on the outer periphery of which an inner race surface facing the outer race surface of the double row is formed, and the inner ring member is press-fitted to the outer race surface of the double row. An inner ring formed with an inner rolling surface opposite to the other, and a vehicle mounting flange or mounting portion for mounting on a vehicle is integrally formed at the inner end of the inner member. The manufacturing method of the hub wheel of the bearing apparatus for wheels as described in 1, and an inward member. Production method of the wheel hub and the inner member of the car wheel bearing device according to claim 5 which is molded at least one of the inner ring member and the inner ring is by cold forging after hot forging.

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