JP2013116689A - Bearing device for wheel and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device for a wheel and a method of manufacturing the same, for improving durability, by securing support rigidity to a moment load, while reducing weight and the size.SOLUTION: A pitch circle diameter PCDi of an inner side rolling element 3 is set in a larger diameter than a pitch circle diameter PCDo of an outer side rolling element 3, a contour shape of an outer member 2 is constituted of an annular recessed part 21 of a cross-sectional circular arc shape formed in an inner side base part of a wheel installing flange 6, a tapered surface 22 of gradually diametrically expanding toward the inner side from the annular recessed part, and an outer peripheral surface 23 of a cylindrical shape of extending to the inner side from the tapered surface 22, a fiber flow of the outer member 2 is continuously formed along the contour shape without being cut, the outer member 2 is formed of medium high carbon steel including carbon by 0.40-0.80 wt.%, and hardening processing is performed by induction hardening over the outer peripheral surface 23 via the tapered surface 22 from outside rolling travel surfaces 2a and 2b of a double row and the annular recessed part 21.

Description

  The present invention relates to a wheel bearing device for rotatably supporting a wheel of an automobile or the like, and more particularly, to a so-called outer ring rotation type in which an outer member rotates together with a wheel, to reduce the weight and size, and to support rigidity against a moment load. The present invention relates to a wheel bearing device that has been secured and improved in durability and a method for manufacturing the same.

  2. Description of the Related Art Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like is such that a hub wheel for mounting a wheel is rotatably supported via a rolling bearing, and there are a drive wheel and a driven wheel. For structural reasons, the inner ring rotating type is generally used for driving wheels and the inner ring rotating and outer ring rotating types are generally used for driven wheels. Since the structure of the mounting portion can be simplified as compared with the inner ring rotating type, it is used as a wheel bearing device for supporting a driven wheel in some automobiles. However, since the outer member, which has a larger diameter than the inner member, is rotated, the moment of inertia is increased, which is disadvantageous compared to the inner ring rotating type in terms of ensuring driving performance and fuel efficiency performance centering on acceleration performance. Become. In order to reduce or eliminate such disadvantages, it is effective to reduce the weight of the outer member. A structure as shown in FIG. 12 is conventionally known as an outer ring rotating type wheel bearing device considered in view of such circumstances.

  The wheel bearing device 100 includes an inner member 101, an outer member 102, a double row of balls 103, and a reinforcing member 104. Of these, the inner member 101 has double-row inner rolling surfaces 101a and 101b formed on the outer peripheral surface, and is supported and fixed to the suspension device in a use state and does not rotate. On the other hand, the outer member 102 integrally has a rotation-side flange 105 on the outer peripheral surface, and double row outer rolling surfaces 102a and 102b are formed on the inner peripheral surface. And it rotates with the wheel (not shown) couple | bonded and fixed to this wheel mounting flange 105 in use condition.

  The reinforcing member 104 has a partially conical cylindrical shape as a whole, with the large-diameter end on the outer peripheral edge of the rotation-side flange 105 and the small-diameter end on the outer peripheral surface of the outer member 102 more than the rotation-side flange 105. It is joined and fixed to the inner part in the axial direction by welding. Furthermore, in order to fix the inner member 101 to the suspension device, a stationary flange 106 is formed on the peripheral surface of the inner member 101. As shown in FIG. 13, a tapped hole 108 for fastening the fixing bolt 107 is provided in the stationary flange 106.

  Here, when turning, for example, an input from a contact portion between the wheel and the road surface is applied to the rotation side flange 105 as a moment in a direction in which the rotation side flange 105 is bent with respect to the main body portion of the outer member 102. That is, since the reinforcing member 104 is provided between the rotation-side flange 105 and the main body portion of the outer member 102, the rotation-side flange 105 is bent with respect to the main body portion of the outer member 102 regardless of the moment load. It can be suppressed. For this reason, even if the outer member 102 is thinned, it is possible to ensure the support rigidity of the wheels and ensure the required performance such as running stability (see, for example, Patent Document 1).

JP 2010-188892 A

  In such a wheel bearing device 100, the reinforcing member 104 is required, so that not only the weight is increased but also the number of assembling steps is increased and the manufacturing cost is increased. In addition, there is a problem that providing the reinforcing member 104 restricts a space for housing the drum brake related parts and makes it difficult to attach and detach the hub bolt for fixing the wheel.

  The present invention has been made in view of the above circumstances, and provides a wheel bearing device and a method for manufacturing the same, which are light and compact, ensure support rigidity against moment load, and improve durability. The purpose is to do.

  In order to achieve such an object, the invention according to claim 1 of the present invention has a wheel mounting flange for mounting a wheel at an end portion on the outer side, and a double row outer rolling surface on the inner periphery. An outer member formed integrally, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small diameter step extending in the axial direction through a step portion inclined from the inner rolling surface An inner member comprising a hub wheel formed with a portion, and an inner ring press-fitted into a small-diameter step portion of the hub wheel and having the other inner rolling surface opposed to the outer rolling surface of the double row on the outer periphery. A double-row rolling element accommodated between the rolling surfaces of the inner member and the outer member, and an inner portion of an annular space formed between the outer member and the inner member. And a seal attached to the opening on the side, and formed by plastically deforming the end of the small-diameter stepped portion radially outward. In the wheel bearing device in which the inner ring is fixed in the axial direction by the tightening portion, the pitch circle diameter of the inner side rolling element of the double row rolling elements is larger than the pitch circle diameter of the outer side rolling element. The outer shape of the outer member is set to be an annular recess having an arc cross section formed at the base on the inner side of the wheel mounting flange, and a tapered surface gradually expanding from the annular recess toward the inner side And a cylindrical outer peripheral surface extending from the tapered surface to the inner side, and the fiber flow of the outer member is formed by being connected along the outer shape without being cut.

  As described above, the double row rolling elements housed in a freely rollable manner between the rolling surfaces of the inner member and the outer member, and the inner part of the annular space formed between the outer member and the inner member. A wheel bearing device in which an inner ring is fixed in an axial direction by a caulking portion formed by plastically deforming an end portion of a small-diameter step portion radially outward. Among the rolling elements in the row, the pitch circle diameter of the inner rolling elements is set to be larger than the pitch circle diameter of the outer rolling elements, and the outer shape of the outer member is the inner diameter of the wheel mounting flange. An annular recess having a circular arc cross section formed in the base, a tapered surface gradually expanding from the annular recess toward the inner side, and a cylindrical outer peripheral surface extending from the tapered surface to the inner side. The fiber flow of the member is not cut and conforms to the outer shape. Because Te is formed connected, there is ensured a weight and size, to ensure support rigidity against moment load, it is possible to provide a wheel bearing apparatus with improved durability.

  Further, as in the invention described in claim 2, the outer member is made of medium-high carbon steel containing carbon of 0.40 to 0.80 wt%, and the double row outer raceway surface is hardened by induction hardening. A predetermined hardened layer may be formed in a range of 58 to 64 HRC, and the outer member is formed of high carbon chrome steel as in the invention of claim 3, and the double row A predetermined hardened layer may be formed so that the outer rolling surface of the steel has a surface hardness of 58 to 64 HRC by induction hardening.

  Further, as in the invention described in claim 4, the surface hardness is set within a range of 50 to 64 HRC by induction hardening from the annular recess of the outer member to the outer peripheral surface through the tapered surface. If the hardened layer is formed, it is possible to ensure the support rigidity against the moment load repeatedly applied, and to improve the durability.

  Further, as in the invention described in claim 5, if the support portion is formed to have a desired roundness and surface roughness by cutting at the inner end of the outer peripheral surface of the outer member, When the double row outer rolling surface is ground, it becomes a guide surface on which the shoe slides.

  Further, as in the invention described in claim 6, the hub bolt is fixed to the wheel mounting flange in a circumferentially equal distribution, and the outer diameter of the support portion is set to be smaller than the pitch circle diameter of the hub bolt. Then, it becomes easy to attach and detach the hub bolt to the wheel mounting flange, and the assembly work and the repair work can be simplified.

  Further, as in the invention according to claim 7, a through hole is formed in the step portion of the hub wheel, and a rotation speed sensor is attached to the through hole so that the detection portion protrudes into the bearing. A pulsar ring facing the detection unit via a predetermined air gap may be attached to the outer member.

  Further, as in the invention described in claim 8, the distance from the forefront of the detection portion of the rotational speed sensor to the shaft center is set to be smaller than the radius of the inscribed circle diameter of the rolling element on the inner side. If it is done, in the assembly process, the hub wheel can be fitted into the outer member without interfering with the rolling elements in a state where the rotational speed sensor is mounted on the hub wheel, and the assemblability can be improved.

  The method invention according to claim 9 of the present invention has a wheel mounting flange for mounting the wheel at the end on the outer side, and a double row outer rolling surface is integrally formed on the inner periphery. An outer member, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction through a step portion inclined from the inner rolling surface is formed. An inner member comprising a hub ring and an inner ring press-fitted into a small-diameter step portion of the hub ring and having the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and the inner member And a double row rolling element accommodated between the rolling surfaces of the outer member and the outer member, and an opening on the inner side of the annular space formed between the outer member and the inner member. An end portion of the small-diameter step portion is formed in front by a caulking portion formed by plastic deformation in a radially outward direction. In the manufacturing method of the wheel bearing device in which the inner ring is fixed in the axial direction, the pitch circle diameter of the inner side rolling element among the double row rolling elements is set larger than the pitch circle diameter of the outer side rolling element. In addition, the outer shape of the outer member is an annular recess having a circular arc cross section formed at the base on the inner side of the wheel mounting flange, and a tapered surface that gradually increases in diameter from the annular recess toward the inner side. The outer member is formed by an outer peripheral surface extending from the tapered surface to the inner side, and the outer member is formed in a substantially cylindrical shape extending in the axial direction from the base portion on the inner side of the wheel mounting flange in advance by hot forging. Thereafter, the portion corresponding to the outer rolling surface on the inner side is expanded by cold rolling to increase the diameter.

  Thus, the pitch circle diameter of the inner side rolling element is set to be larger than the pitch circle diameter of the outer side rolling element, and the outer shape of the outer member is formed at the inner side base of the wheel mounting flange. An annular recess having a circular arc cross section formed, a tapered surface gradually increasing in diameter from the annular recess toward the inner side, and an outer peripheral surface extending from the tapered surface to the inner side. By forming a substantially cylindrical shape that extends in the axial direction from the base on the inner side of the wheel mounting flange by cold forging, and then expanding the part corresponding to the outer rolling surface on the inner side by cold rolling Because it is formed, it is possible to form an outer member that is connected along the outer shape without cutting the fiber flow, ensuring support rigidity against moment load, and improving durability It is possible to provide a wheel bearing apparatus which aimed.

  Further, as in the invention described in claim 10, the cold rolling forming jig is composed of an outer roller disposed on the outer diameter side of the outer member and an inner roller disposed on the inner diameter side. The outer roller is formed in the shape of an annular recess, a tapered surface and an outer peripheral surface of the outer member, and the inner roller is formed in the shape of the double row outer rolling surface, Since the outer member is rolled while the inner roller is decentered toward the outer roller side while being pressed against the outer diameter of the outer member, the material loss of the material of the outer member is significantly reduced. Therefore, cost reduction can be achieved.

  A wheel bearing device according to the present invention has an outer member integrally including a wheel mounting flange for mounting a wheel at an end portion on the outer side, and a double row outer rolling surface formed integrally on the inner periphery. A hub wheel formed on the outer periphery with one inner rolling surface facing the double-row outer rolling surface and a small diameter step portion extending in the axial direction through a step portion inclined from the inner rolling surface, and An inner member comprising an inner ring press-fitted into a small-diameter step portion of the hub wheel and having the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and the inner member and the outer member A double row rolling element accommodated between both rolling surfaces of the member, and a seal attached to an opening on the inner side of the annular space formed between the outer member and the inner member The inner ring is pivoted by a caulking portion formed by plastically deforming an end portion of the small-diameter stepped portion radially outward. In the wheel bearing device fixed in the direction, the pitch circle diameter of the inner side rolling elements of the double row rolling elements is set larger than the pitch circle diameter of the outer side rolling elements, and the outer The outer shape of the rectangular member has an annular recess formed in the base portion on the inner side of the wheel mounting flange, a tapered surface gradually increasing in diameter from the annular recess toward the inner side, and an inner surface from the tapered surface. It is composed of a cylindrical outer peripheral surface extending to the side, and the fiber flow of the outer member is formed by being connected along the outer shape without being cut, so that it is lightweight and compact, and supports moment load It is possible to provide a wheel bearing device that ensures rigidity and improves durability.

  Further, the method for manufacturing a wheel bearing device according to the present invention has a wheel mounting flange for mounting a wheel at the end on the outer side, and a double row outer rolling surface is integrally formed on the inner periphery. An outer member, an inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction through a step portion inclined from the inner rolling surface. And an inner member comprising an inner ring that is press-fitted into a small-diameter step portion of the hub ring and has an outer ring formed on the outer periphery thereof and facing the outer rolling surface of the double row. A double-row rolling element housed between the rolling surfaces of the member and the outer member so as to roll freely, and an opening on the inner side of the annular space formed between the outer member and the inner member And a crimped portion formed by plastically deforming the end portion of the small-diameter stepped portion radially outward. In the manufacturing method of the wheel bearing device in which the inner ring is fixed in the axial direction, the pitch circle diameter of the inner side rolling element of the double row rolling elements is larger than the pitch circle diameter of the outer side rolling element. The outer member has an outer shape with an arc-shaped recess having an arc cross section formed at the base on the inner side of the wheel mounting flange, and a taper that gradually expands from the annular recess toward the inner side. And an outer peripheral surface extending from the tapered surface to the inner side, and the outer member is formed in a substantially cylindrical shape extending in the axial direction from the base on the inner side of the wheel mounting flange in advance by hot forging. Then, it is formed by expanding the part corresponding to the outer rolling surface on the inner side by cold rolling, so that the fiber flow is connected along the outer shape without being cut. Tsu can form the outer member is to ensure support rigidity against moment load, it is possible to provide a wheel bearing apparatus with improved durability.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is a principal part enlarged view which shows the seal part of FIG. It is sectional drawing which shows the fiber flow of the outward member of FIG. (A)-(e) is explanatory drawing which shows the 1st forge process of the outward member which concerns on this invention. (A)-(c) is explanatory drawing which shows the 2nd forge process of the outward member which concerns on this invention. (A) is explanatory drawing which shows the turning and grinding process of the outer member which concerns on this invention, (b) is explanatory drawing which shows the heat processing pattern of an outer member. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. (A) is a longitudinal cross-sectional view which shows 3rd Embodiment of the wheel bearing apparatus which concerns on this invention, (b) is a principal part enlarged view which shows the detection part of (a). (A)-(c) is explanatory drawing which shows the components matching process of the bearing apparatus for wheels which concerns on this invention. (A)-(c) is explanatory drawing which shows a component matching process same as the above. (A)-(c) is explanatory drawing which shows the axial clearance measuring process of the bearing apparatus for wheels which concerns on this invention. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus. FIG. 13 is a perspective view of FIG. 12.

  An outer member integrally having a wheel mounting flange for attaching a wheel to an end on the outer side, a double row outer rolling surface formed integrally on the inner periphery, and an outer rolling of the double row on the outer periphery A hub wheel formed with one inner rolling surface facing the surface and a small diameter step portion extending in the axial direction via a step portion inclined from the inner rolling surface, and the hub wheel is press-fitted into the small diameter step portion of the hub ring. An inner member composed of an inner ring having an outer ring formed with the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and rolling between both rolling surfaces of the inner member and the outer member. A plurality of rolling elements accommodated freely, and a seal attached to an opening on the inner side of an annular space formed between the outer member and the inner member, and an end of the small diameter step portion Wheel bearing device in which the inner ring is fixed in the axial direction by a caulking portion formed by plastically deforming the portion radially outward The pitch circle diameter of the inner side rolling element of the double row rolling elements is set to be larger than the pitch circle diameter of the outer side rolling element, and the outer shape of the outer member is the wheel mounting Consists of an annular recess formed in the base of the inner side of the flange, an arc-shaped concave section, a tapered surface gradually expanding from the annular recess toward the inner side, and a cylindrical outer peripheral surface extending from the tapered surface to the inner side The outer member fiber flow is formed by being connected along the outer shape without being cut, and the outer member is formed of medium to high carbon steel containing 0.40 to 0.80 wt% of carbon, A predetermined hardened layer is formed by induction hardening over the outer peripheral surface from the double row outer rolling surface and the annular recess through the tapered surface.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, FIG. 2 is an enlarged view of a main part showing a seal part of FIG. 1, and FIG. 3 is an outer member of FIG. FIGS. 4A to 4E are explanatory views showing the first forging process of the outer member according to the present invention, and FIGS. 5A to 5C are the present invention. FIG. 6A is an explanatory view showing a turning / grinding process of the outer member according to the present invention, and FIG. 6B is a heat treatment of the outer member. It is explanatory drawing which shows a pattern. In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outer side (left side in FIG. 1), and the side closer to the center is referred to as the inner side (right side in FIG. 1).

  This wheel bearing device is for a driven wheel called the third generation, and is an inner member 1 serving as a stationary member, an outer member 2 serving as a rotating member, and a rolling member between both members 1 and 2. It has double row rolling elements (balls) 3 and 3 which are accommodated freely. The inner member 1 includes a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4 through a predetermined shimiro.

  The hub wheel 4 is formed on the outer periphery with one (inner side) inner rolling surface 4a and a small-diameter stepped portion 4b extending in the axial direction via a stepped portion 7a inclined from the inner rolling surface 4a. The inner ring 5 is formed with the other (outer side) inner raceway surface 5a on the outer periphery and is press-fitted into the small-diameter stepped portion 4b of the hub wheel 4 to form a back-to-back type double row angular contact ball bearing. The inner ring 5 is fixed to the hub ring 4 in the axial direction in a state where a predetermined bearing preload is applied by a crimping portion 8 formed by plastically deforming the end of 4b. The inner ring 5 and the rolling element 3 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core part by quenching.

  The hub wheel 4 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner diameter rolling surface 4a as well as an outer diameter surface serving as a fitting portion of a seal 12 described later from a small diameter step portion. A predetermined hardened layer (indicated by cross-hatching in the figure) 9 is formed in the range of 58 to 64 HRC by induction hardening over the outer peripheral surface of 4b. The hardened layer 9 is stopped at the end of the small-diameter stepped portion 4b, and the crimped portion 8 is a non-hardened layer with the surface hardness after forging. As a result, the fretting resistance of the small-diameter stepped portion 4b serving as the fitting portion of the inner ring 5 is improved, and the plastic working of the crimped portion 8 can be performed smoothly without occurrence of minute cracks.

  The outer member 2 integrally has a wheel mounting flange 6 for attaching a wheel (not shown) to an end portion on the outer side, and hub bolts 6 a are implanted in the circumferential direction of the wheel mounting flange 6. In addition, a circular hole 6c is formed between the hub bolts 6a. In addition, thick ribs 6b are formed radially around the hub bolt 6a from the base. The rib 6b and the circular hole 6c can reduce the weight and rigidity of the outer member 2, and can secure sufficient strength even when a large bending moment load is applied to the wheel mounting flange 6. .

  Further, on the inner periphery of the outer member 2, a hub wheel is provided via an outer outer rolling surface 2a facing the inner rolling surface 5a of the inner ring 5 and a step 7b inclined from the outer rolling surface 2a. 4, the inner side outer rolling surface 2b opposite to the inner side rolling surface 4a is integrally formed. Double-row rolling elements 3 and 3 are accommodated between these rolling surfaces and are held by the cages 10a and 10b so as to be freely rollable. This outer member 2 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and double row outer rolling surfaces 2a and 2b described later have a surface hardness of 58 to 64 HRC by induction hardening. It has been cured to the extent of.

  The material of the outer member 2 may be formed of high carbon chrome steel such as SUJ2 similar to the inner ring 5. In this case, at least the double-row outer raceway surfaces 2a and 2b are hardened by induction hardening in the range of 58 to 64 HRC, instead of hardening by sub-quenching.

  An end cap 11 is attached to an opening on the outer side of the annular space formed between the outer member 2 and the inner member 1, and a seal 12 is attached to the opening on the inner side. Leakage of grease sealed in the outside and rain water, dust, etc. from entering the inside of the bearing are prevented.

  The end cap 11 is formed into a substantially U-shaped cross section by pressing from an austenitic stainless steel plate (JIS standard SUS304 system, etc.) or a rust-proof cold rolled steel sheet (JIS standard SPCC system, etc.). Has been.

  Further, as shown in an enlarged view in FIG. 2, the seal 12 is configured by a so-called pack seal including a slinger 13 and an annular seal plate 14 that are arranged to face each other. The slinger 13 has a cross section by press working from a rust-proof steel plate, for example, an austenitic stainless steel plate or a ferritic stainless steel plate (JIS standard SUS430 series, etc.) or a rust-proof cold-rolled steel plate. The cylindrical portion 13a is formed in a substantially L shape and is press-fitted into the outer diameter of the hub wheel 4, and the upright plate portion 13b extending radially outward from the cylindrical portion 13a.

  On the other hand, the seal plate 14 includes a cored bar 15 that is fitted into the end of the outer member 2 on the inner side, and a seal member 16 that is integrally joined to the cored bar 15 by vulcanization adhesion. The metal core 15 has a substantially L-shaped cross section by press working from a general cold-rolled steel plate or a cold-rolled steel plate subjected to rust prevention.

  Further, the seal member 16 is made of synthetic rubber such as NBR (acrylonitrile-butadiene rubber), extends in a radially outward direction, and slidably contacts the standing plate portion 13b of the slinger 13 via a predetermined axial shimiro. 16a, and a dust lip 16c and a grease lip 16c that extend in a forked manner on the inner diameter side and slidably contact the cylindrical portion 13a of the slinger 13 via a predetermined radial shimiro. As the material of the seal member 16, in addition to the exemplified NBR, for example, HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), etc. having excellent heat resistance, heat resistance, chemical resistance, etc. Examples thereof include ACM (polyacrylic rubber), FKM (fluororubber), and silicon rubber, which are excellent in the above.

  In addition, although the wheel bearing apparatus comprised by the double row angular contact ball bearing which used the ball for the rolling element 3 was illustrated here, it is not restricted to this, The double row tapered roller bearing which used the tapered roller for the rolling element 3 It may be configured by.

  In this embodiment, the pitch circle diameter PCDi of the inner side rolling element 3 is set larger than the pitch circle diameter PCDo of the outer side rolling element 3 (PCDi> PCDo). The sizes of the double-row rolling elements 3 and 3 do not have to be the same on the left and right. Due to the difference in the pitch circle diameters PCDo and PCDi, the number of inner-side rolling elements 3 is larger than the number of outer-side rolling elements 3. There are also many settings.

  The outer shape of the hub wheel 4 includes a counter portion 17 from the groove bottom portion of the inner rolling surface 4a, a step portion 7a formed to be inclined from the counter portion 17, and a shoulder portion 4c with which the inner ring 5 is abutted. It continues to the small diameter step 4b. On the other hand, in the outer member 2, the inner side outer rolling surface 2 b is formed with a larger diameter than the outer side outer rolling surface 2 a with the difference in pitch circle diameters PCDo and PCDi, and the inner side outer rolling surface is formed. An outer rolling surface 2a on the outer side is formed through a stepped portion 7b inclined from the running surface 2b.

  In the wheel bearing device having such a configuration, the pitch circle diameter PCDi of the inner side rolling element 3 is set to be larger than the pitch circle diameter PCDo of the outer side rolling element 3, and the number of the rolling elements 3 is accordingly increased. Since the number of the side is set more than the number of the outer side, the bearing space can be effectively utilized to reduce weight and compactness, and the bearing rigidity of the inner side part can be increased compared to the outer side, The life of the bearing can be extended.

  Here, a mounting portion 19 having a mortar-shaped recess 18 is formed at the inner end of the hub wheel 4. The depth of the recess 18 is an axial dimension in the vicinity of the shoulder portion 4c from the end surface on the inner side of the hub wheel 4, and the mounting portion 19 of the hub wheel 4 has a substantially uniform thickness. Thereby, weight reduction can be achieved, maintaining the intensity | strength of the hub ring 4. FIG. In the present embodiment, a plurality of bolt holes 20 are formed in the attachment portion 19 and attached to the suspension device by fixing bolts (not shown) fastened to the bolt holes 20.

  Moreover, since the outer side rolling surface 2b on the inner side is formed with a larger diameter than the outer side rolling surface 2a on the outer side, the outer shape of the outer member 2 is formed at the base portion on the inner side of the wheel mounting flange 6. A tapered surface 22 that gradually increases in diameter from the formed circular recess 21 having an arcuate cross section toward the inner side, and a cylindrical outer peripheral surface 23 that is the outer diameter side of the outer rolling surface 2b on the inner side from the tapered surface 22. It consists of By forming the annular recess 21, a hub bolt (not shown) for fixing the wheel can be easily attached and detached, work efficiency in the manufacturing process can be improved, and repair work in the market can be simplified.

  This outer member 2 forms a cylindrical outer peripheral surface as in the prior art by a forging process (first forging process) in advance, and outer rolling on the outer side by a cold rolling process (second forging process). A portion corresponding to the surface 2a is prepared, and a portion corresponding to the outer side rolling surface 2b on the inner side is increased in diameter. Thereby, as schematically shown in FIG. 3, it is possible to form the outer member 2 that is connected along the outer shape without cutting the fiber flow F, ensuring the supporting rigidity against the moment load, and the durability. It is possible to provide a wheel bearing device with improved performance. In the figure, a two-dot chain line indicates the outer member 2 in a finished product state.

Next, the forging method of the outer member according to the present invention will be described with reference to FIGS. 4 and 5.
FIGS. 4A to 4E show the first forging process, and FIGS. 5A to 5C show the second forging process, respectively.
First, as shown to Fig.4 (a), billet W0 used as a forge raw material is cut | disconnected by predetermined length from a bar material. The billet W0 is heated to a predetermined temperature and installed to form a drum-shaped billet W1 as shown in FIG. Next, as shown in (c) and (d), by hot forging, finish forming is performed through rough forming to form the outer shape of the outer member, and finally, as shown in (e), a punch ( (Not shown), the inner diameter is removed, and the outer member 2 'by hot forging is completed.

  Further, in the second forging step, as shown in FIG. 5A, the second forging step is formed by cold rolling. This cold rolling forming jig is composed of an outer roller 24 and an inner roller 25. The outer roller 24 is pressed against the outer diameter side of the outer member 2 ′, and the inner roller (mandrel) 25 on the inner diameter side. Is inserted and cold rolled. Here, the outer roller 24 is formed in the shape of the annular recess 21, the tapered surface 22 and the cylindrical outer peripheral surface 23 of the outer member 2 described above. On the other hand, the inner roller 25 is formed in the shape of a double-row outer rolling surface 2a, 2b and an inclined step portion 7b.

  Then, as shown in (b) and (c), the outer roller 24 is pressed against the outer diameter of the outer member 2 ′ while the inner roller 25 is decentered toward the outer roller 24, and the outer member is used together. 2 'is rolled and formed into a shape that follows the shape of the outer roller 24 and the inner roller 25 to complete the outer member 2 "by cold rolling. Thus, the cold rolling process is adopted. Can form an outer member 2 ″ connected without cutting the fiber flow, ensuring support rigidity against moment load, improving durability, and material of the outer member 2 ″. The material loss can be significantly reduced, and the cost can be reduced.

  FIG. 6A is an explanatory view showing a turning / grinding process of the outer member. In the outer member 2 ″ (indicated by a two-dot chain line in the figure) formed through the first and second forging steps, a bolt hole 26 and a circular hole 6c into which a hub bolt (not shown) is press-fitted are punched. Then, the outer rolling surfaces 2a and 2b of the double row are finished by grinding, and the inner side of the outer peripheral surface 23 of the outer member 2 is then formed. A support portion 27 is formed to have a desired roundness and surface roughness by cutting (grinding or turning) at the end of the outer periphery of the outer surface 2a, 2b. When processing, a shoe (not shown) serves as a guide surface in sliding contact.

  Here, the outer diameter dimension d1 of the support portion 27 is set to a smaller diameter (d1 <PCDh) than the pitch circle diameter PCDh of the hub bolt (not shown). Thereby, it becomes easy to attach and detach the hub bolt to the wheel mounting flange 6, and the assembling work and the repair work can be simplified.

  FIG. 6B is an explanatory diagram showing a heat treatment pattern of the outer member. The outer member 2 is formed with predetermined hardened layers 28a and 28b in a range of 58 to 64 HRC by induction hardening on the outer rolling surfaces 2a and 2b of the double row (in the figure, by cross-hatching). Show). Further, in the present embodiment, the surface hardness is set in the range of 50 to 64 HRC by induction hardening from the annular recess 21 formed in the base portion on the inner side of the wheel mounting flange 6 to the outer peripheral surface 23 through the tapered surface 22. A predetermined hardened layer 29 is formed. As a result, it is possible to ensure the supporting rigidity against the moment load repeatedly applied and to improve the durability, but the hardened layer 29 may be omitted. In addition, although the hardened layers 28a and 28b of the double-row outer raceway surfaces 2a and 2b are illustrated as being separated and independent here, the hardened layers 28a and 28b including the stepped portion 7b are continuous. It may be connected.

  FIG. 7 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention. The second embodiment is basically different from the first embodiment (FIG. 1) described above except that the configuration of the pilot part is different, and the same parts are the same parts or parts or parts having the same function. Are denoted by the same reference numerals and detailed description thereof is omitted.

  The wheel bearing device includes an inner member 1, an outer member 30, and double row rolling elements 3, 3 accommodated between the members 1, 30 so as to roll freely. The inner member 1 includes a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4 through a predetermined shimiro.

  A seal 12 is attached to the opening on the inner side of the annular space formed between the outer member 30 and the inner member 1, leakage of grease sealed inside the bearing to the outside, rainwater and Dust and the like are prevented from entering the bearing.

  The outer member 30 integrally has a wheel mounting flange 6 at an end portion on the outer side, and hub bolts 6a are implanted at equal intervals in the circumferential direction of the wheel mounting flange 6, and a circular hole 6c is interposed between the hub bolts 6a. Is formed. In addition, thick ribs 6b are formed radially from the base around the hub bolt 6a.

  Further, the outer shape of the outer member 30 includes an annular concave portion 21 having a circular arc cross section formed at the base portion on the inner side of the wheel mounting flange 6, a tapered surface 22, and a cylindrical outer peripheral surface 23. The outer member 30 is made of medium-high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and has a high frequency over the outer circumferential surface 23 from the double row outer rolling surfaces 2a and 2b and the annular recess 21. The surface hardness is set to a range of 50 to 64 HRC by quenching.

  Here, in this embodiment, a separate pilot member 31 is fitted to the outer end of the outer member 30. The pilot member 31 guides a wheel and a brake rotor (not shown), and has an end cap that prevents leakage of grease sealed inside the bearing and prevents rainwater and dust from entering the bearing from the outside. It has a function. Thereby, since the shape of the outer member 30 can be simplified, it becomes easy to forge, the number of processing steps can be reduced, and the cost can be reduced. The pilot member 31 is formed into a cup shape with a substantially U-shaped cross section by press working from an austenitic stainless steel plate or a cold-rolled steel plate treated with rust.

  FIG. 8A is a longitudinal sectional view showing a third embodiment of the wheel bearing device according to the present invention, and FIG. 8B is an enlarged view of a main part showing the detection part of FIG. The third embodiment is basically different from the second embodiment (FIG. 7) described above except that the configuration of the hub wheel is partially different, and other parts having the same parts or similar functions or Parts are denoted by the same reference numerals and detailed description thereof is omitted.

  The wheel bearing device shown in FIG. 8A includes an inner member 32, an outer member 30, and double-row rolling elements 3, 3 accommodated between the members 32, 30 so as to freely roll. Yes. The inner member 32 includes a hub ring 33 and an inner ring 5 press-fitted into the hub ring 33 through a predetermined shimiro.

  The hub wheel 33 is formed with one (inner side) inner rolling surface 4a and a small-diameter stepped portion 4b extending in the axial direction from the inner rolling surface 4a via the stepped portion 7a. The inner ring 5 is formed with the other (outer side) inner rolling surface 5a on the outer periphery and is press-fitted into the small-diameter stepped portion 4b of the hub wheel 33 to form a back-to-back type double-row angular ball bearing. The inner ring 5 is fixed to the hub ring 33 in the axial direction in a state in which a predetermined bearing preload is applied by a caulking portion 8 formed by plastically deforming the end portion of 4b.

  The hub wheel 33 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon, such as S53C, and includes the inner rolling surface 4a and the outer diameter surface serving as the fitting portion of the seal 12 to the small diameter step portion 4b. The surface is hardened in the range of 58 to 64 HRC by induction hardening over the outer peripheral surface.

  Here, a through hole 34 is formed in the stepped portion 7 a of the hub wheel 33, and a rotation speed sensor 35 is attached to the through hole 34. The rotational speed sensor 35 is formed of a synthetic resin such as PA 66 that can be injection-molded, and includes a magnetic detection element such as a Hall element, a magnetoresistive element (MR element), and the like whose characteristics change according to the flow direction of magnetic flux, and the magnetic detection element An IC (not shown) or the like in which a waveform shaping circuit for adjusting the output waveform is embedded is embedded, and constitutes an automobile ABS that detects the rotational speed of the wheel and controls its rotational speed. And the detection part 35a protrudes inside the bearing.

  On the other hand, a pulsar ring 36 facing the detection portion 35a of the rotational speed sensor 35 via a predetermined axial clearance (air gap) is mounted on the outer member 30, and is enlarged as shown in FIG. A cylindrical fitting portion 37a that is press-fitted into the inner diameter of the outer member 30, a support ring 37 that includes a standing plate portion 37b that extends radially inward from the fitting portion 37a, and a standing plate of the support ring 37 The magnetic encoder 38 is integrally joined to the portion 37b by vulcanization adhesion. The support ring 37 is formed in an L shape by pressing from a ferromagnetic steel plate, for example, a ferritic stainless steel plate or a cold-rolled cold-rolled steel plate, and is formed in an annular shape as a whole.

  The magnetic encoder 38 constitutes a rotary encoder for detecting the rotational speed of the wheel by mixing magnetic powder such as ferrite in an elastomer such as rubber and magnetizing the magnetic poles N and S alternately in the circumferential direction. Here, the pulsar ring 36 including the magnetic encoder 38 made of a rubber magnet is illustrated, but the present invention is not limited to this, and any configuration may be used as long as the characteristics change alternately in the circumferential direction and at equal intervals. It may be a pulsar ring made of steel plate in which the through holes and irregularities are formed, or may be formed of a sintered alloy. Further, a plastic magnet may be joined.

  Here, the height of the outermost diameter of the detecting portion 35a of the rotational speed sensor 35, that is, the distance R1 from the axis to the forefront is made smaller than the radius R2 of the inscribed circle diameter of the inner rolling element 3. (R1 <R2). As a result, in the assembly process, the hub wheel 33 can be fitted into the outer member 30 without interfering with the inner rolling element 30 with the rotational speed sensor 35 mounted, thereby improving the assemblability. Can do.

Next, the matching method of the wheel bearing device according to the present invention will be described in detail with reference to FIGS. 9 and 10.
First, the groove diameter of the outer member 2 is measured by the measuring jig 39 using the outer side surface 6d of the wheel mounting flange 6 as a reference surface, as shown in FIG. This measuring jig 39 is integrally provided with a bifurcated stylus 39a, 39b, and can simultaneously measure the rolling element contact point diameter of the double row outer rolling surfaces 2a, 2b, so-called touch diameter. The dimension (measurement width) between the stylus 39a and 39b is L, the distance from the reference surface (side surface 6d of the wheel mounting flange 6) to the inner stylus 39b is L ', and the stylus 39a and 39b are double-rowed. The contact needles 39a and 39b are brought into contact with the touch diameters A1 and A2 of the outer rolling surfaces 2a and 2b, and an average value ΔA of deviation from the median value in both grooves is measured.

  Next, as shown in FIG. 9B, the groove diameter of the inner member 1 is measured by using the shoulder portion 4c of the hub wheel 4 as a reference plane and the inner rolling surface on the inner side with the measurement width L1 as a reference. The stylus 40a is brought into contact with the touch diameter B1 of 4a, and the stylus 40b is brought into contact with the fitting diameter (the outer diameter of the small diameter step portion 4b) B2 of the inner ring 5, so that the deviations ΔB1 and ΔB2 from the respective median values. Measure.

  Further, as shown in FIG. 9C, the groove diameter of the inner ring 5 is measured by using the small end surface 5b of the inner ring 5 as a reference plane and the touch diameter of the outer side inner rolling surface 5a based on the measurement width L2. The stylus 41a is brought into contact with C1 and the stylus 41b is brought into contact with the inner diameter C2, and the deviations ΔC1 and ΔC2 from the respective median values are measured.

Based on the measurement results of the outer member 2, the inner member 1, and the inner ring 5, so-called rolling element matching is performed in which various outer diameters of the rolling elements 3 stocked are selected by the following calculation.
1. The calculation of the influence ΔX on the inner raceway surface 5a of the inner ring 5 due to the fitting of the hub ring 4 and the inner ring 5 is as follows:
ΔX = λ · (ΔB2−ΔC2) where λ is the inner ring groove expansion coefficient (calculated value or experimental value).
2. The calculation of the difference (ΔY) in the touch diameter between the inner ring 5 and the hub ring 4 in consideration of the fit is
ΔY = (ΔB1 + ΔC1 + ΔX) / 2
3. The calculation of the difference (ΔT) in the touch diameter between the outer member 2 and the inner member 1 (hub wheel 4, inner ring 5) is as follows:
ΔT = ΔA-ΔY
4. Calculation of selection of outer diameter rank (ΔDw) of rolling element 3
ΔDwmin. = (Smax.-SX-k1 · ΔT) / kb
ΔDwmax. = (Smin.-SX-k1 · ΔT) / kb
Here, Smax. Smin. Is the standard range of the axial clearance before caulking, SX is the median value of the axial clearance standard value, SX = (Smax. + Smin.) / 2, k1 is the axial clearance influence coefficient of the groove diameter, and kb is the rolling clearance Axial clearance influence coefficient of the outer diameter of the moving body 3 (calculated value or experimental value)
5. As shown in FIG. 10 (a), the outer diameter rank of the rolling element 3 in the measured range, here, five ranks of -4 μm to +4 μm are used as the rolling element / cage assembly as shown in FIG. 10 (b). Incorporate into. Note that the outer diameter rank of the rolling element 3 is not limited to the illustrated five ranks, and may be appropriately selected within a range of 3 to 9 ranks.

Next, the axial clearance measuring method for the wheel bearing device according to the present invention will be described in detail with reference to FIG.
1. As shown in (a), in the step of press-fitting the inner ring 5 into the small diameter step 4b of the hub wheel 4, the press-fitting is temporarily stopped just before the small end surface 5b of the inner ring 5 comes into contact with the shoulder 4c of the hub ring 4. The position T1 of the inner ring 5 at the time, the outer member 2 or the inner member 1 is moved in the axial direction, and the axial clearance (positive clearance) ΔS is measured. That is, the amount of movement when the rolling element 3 and the rolling contact surface come into contact with the outer side from the position where the rolling member 3 and the rolling contact surface contact with the inner side is measured.
2. As shown in (b), the amount of movement ΔS1 of the inner ring 5 can be calculated by measuring the position T2 of the inner ring 5 when the inner ring 5 is press-fitted and brought into contact with the shoulder 4c of the hub ring 4. it can. That is, the movement amount ΔS1 of the inner ring 5 can be calculated by ΔS1 = T1−T2.
3. The axial clearance Sb before caulking is Sb = ΔS−ΔS1.
4). As shown in (c), in the caulking step, by measuring the position T3 of the inner ring 5 after caulking, the movement amount ΔS2 of the inner ring 5 due to caulking can be calculated. That is, ΔS2 = T2−T3.
5. Next, the axial clearance reduction amount ΔS3 due to the caulking process is ΔS3 = kx · ΔS2. Thereby, the axial clearance S (negative clearance) after crimping can be calculated by S = Sb−ΔS3. Here, kx is a clearance reduction coefficient.

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

  The wheel bearing device according to the present invention can be applied to a third-generation outer ring rotation type wheel bearing device.

1, 32 Inner member 2, 30 Outer member 2 'Outer member 2 after hot forging Outer member 2a, 2b after cold rolling Outer rolling surface 3 Rolling elements 4, 33 Hub wheels 4a, 5a Inner rolling surface 4b Small diameter step portion 4c Shoulder portion 4d Inner end surface 5 Inner ring 5b Small end surface 5c Inner diameter 6 Wheel mounting flange 6a Hub bolt 6b Rib 6c Circular hole 6d Outer side surface 7a, 7b Step portion 8 of wheel mounting flange Clamping portion 9, 28a, 28b, 29 Hardened layer 10a, 10b Cage 11 End cap 12 Seal 13 Slinger 13a Cylindrical portion 13b, 37b Standing plate portion 14 Seal plate 15 Core metal 16 Seal member 16a Side lip 16b Dustrip 16c Grease lip 17 Counter part 18 Recess 19 Mounting part 20, 26 Bolt hole 21 Annular recess 22 Tapered surface 23 Outer surface 24 Outer roller 25 Inside Roller 27 Support portion 31 Pilot member 34 Through hole 35 Rotational speed sensor 35a Detection portion 36 Pulsar ring 37 Support ring 37a Fitting portion 38 Magnetic encoder 39 Measuring jigs 39a, 39b, 40a, 40b, 41a, 41b Stylus 100 Wheel Bearing device 101 Inner member 101a, 101b Inner rolling surface 102 Outer member 102a, 102b Outer rolling surface 103 Ball 104 Reinforcement member 105 Rotating side flange 106 Stationary side flange 107 Fixing bolt 108 Tap holes A1, A2 Outer member Touch diameter B1 of the outer raceway surface of the inner ring B2 Touch diameter of the inner raceway surface of the hub wheel B2 Fit diameter C1 of the inner ring C2 Touch diameter of the inner raceway surface of the inner ring C2 Inner ring inner diameter ΔA Touch diameter of the outer raceway surface of the double row The average value ΔB1 of the deviation from the median value at the center ΔB2 The deviation from the median value of the touch diameter of the inner raceway surface of the hub wheel Deviation from the median of the fitting diameter of the inner ring ΔC1 Deviation from the median of the touch diameter of the inner ring rolling surface of the inner ring ΔC2 Deviation from the median of the inner diameter of the inner ring ΔDw Outer diameter rank of the rolling element ΔDwmax. Maximum value ΔDwmin Minimum value of the outer diameter rank of the rolling element k1 Axial clearance influence coefficient kb of the groove diameter Axial clearance influence coefficient kx of the outer diameter of the rolling element Clearance reduction coefficient L, L ', L1, L2 by caulking Width PCDh Pitch circle diameter of hub bolt PCDi Pitch circle diameter of inner side rolling element PCDo Pitch circle diameter of outer side rolling element R1 Height of outermost diameter of detector R2 Radius of inscribed circle diameter of inner side rolling element S Bearing axial clearance after caulking Sb Bearing axial clearance before caulking Smax. Maximum axial clearance Smin. Minimum axial clearance SX before tightening SX Median standard value of axial clearance ΔS Bearing axial clearance ΔS1, ΔS2 Amount of inner ring travel ΔS3 Axial clearance reduction T1, T2, T3 Inner ring hub Position from inner end face of wheel ΔT Difference in touch diameter between outer member and inner member W0, W1 Billet ΔX Influence on inner raceway of inner ring ΔY Difference in touch diameter between inner ring and hub ring λ Inner ring groove expansion coefficient

Claims (10)

An outer member integrally having a wheel mounting flange for attaching a wheel to an end on the outer side, and a double row outer rolling surface formed integrally on the inner periphery;
A hub wheel formed on the outer periphery with one inner rolling surface facing the outer rolling surface of the double row, and a small-diameter step portion extending in the axial direction via a step portion inclined from the inner rolling surface, and An inner member composed of an inner ring press-fitted into the small-diameter step portion of the hub wheel and having the other inner rolling surface opposed to the outer rolling surface of the double row on the outer periphery;
A double row rolling element housed so as to be freely rollable between both rolling surfaces of the inner member and the outer member;
A seal attached to an opening on the inner side of the annular space formed between the outer member and the inner member;
In the wheel bearing device in which the inner ring is fixed in the axial direction by a caulking portion formed by plastically deforming an end portion of the small diameter step portion radially outwardly,
Among the double row rolling elements, the pitch circle diameter of the inner side rolling elements is set larger than the pitch circle diameter of the outer side rolling elements,
The outer shape of the outer member is an annular recess having a circular arc cross section formed at the base on the inner side of the wheel mounting flange, a tapered surface gradually expanding from the annular recess toward the inner side, and the tapered surface. A wheel bearing device comprising: a cylindrical outer peripheral surface extending from an inner side to an inner side, wherein the fiber flow of the outer member is connected along the outer shape without being cut.   The outer member is formed of medium to high carbon steel containing carbon of 0.40 to 0.80 wt%, and the outer hardened surface of the double row has a predetermined hardness layer in the range of 58 to 64 HRC by induction hardening. The wheel bearing device according to claim 1, wherein the wheel bearing device is formed.   The outer member is made of high carbon chromium steel, and a predetermined hardened layer is formed on the outer rolling surface of the double row by induction hardening in a range of 58 to 64 HRC. Wheel bearing device.   A predetermined hardened layer is formed in a range of surface hardness of 50 to 64 HRC by induction hardening from the annular recess of the outer member to the outer peripheral surface through the tapered surface. A wheel bearing device according to claim 1.   The wheel bearing device according to any one of claims 1 to 4, wherein a support portion is formed to have a desired roundness and surface roughness by cutting at an inner end portion of the outer peripheral surface of the outer member.   The wheel bearing device according to claim 5, wherein hub bolts are fixed at equal intervals in the circumferential direction of the wheel mounting flange, and an outer diameter of the support portion is set to be smaller than a pitch circle diameter of the hub bolt.   A through hole is formed in the step portion of the hub wheel, and a rotation speed sensor is attached to the through hole so that the detection unit protrudes into the bearing, and faces the detection unit via a predetermined air gap. The wheel bearing device according to claim 1, wherein a pulsar ring is attached to the outer member.   The wheel bearing device according to claim 7, wherein a distance from the forefront of the detection portion of the rotation speed sensor to the shaft center is set to be smaller than a radius of an inscribed circle diameter of the inner rolling element. . An outer member integrally having a wheel mounting flange for attaching a wheel to an end on the outer side, and a double row outer rolling surface formed integrally on the inner periphery;
A hub wheel formed on the outer periphery with one inner rolling surface facing the outer rolling surface of the double row, and a small-diameter step portion extending in the axial direction via a step portion inclined from the inner rolling surface, and An inner member composed of an inner ring press-fitted into the small-diameter step portion of the hub wheel and having the other inner rolling surface opposed to the outer rolling surface of the double row on the outer periphery;
A double row rolling element housed so as to be freely rollable between both rolling surfaces of the inner member and the outer member;
A seal attached to an opening on the inner side of the annular space formed between the outer member and the inner member;
In the method of manufacturing a wheel bearing device in which the inner ring is fixed in the axial direction by a caulking portion formed by plastically deforming an end portion of the small diameter step portion radially outwardly,
Among the double row rolling elements, the pitch circle diameter of the inner side rolling elements is set larger than the pitch circle diameter of the outer side rolling elements,
The outer shape of the outer member is an annular recess having a circular arc cross section formed at the base on the inner side of the wheel mounting flange, a tapered surface gradually expanding from the annular recess toward the inner side, and the tapered surface. The outer member is formed in a cylindrical shape extending in the axial direction from the base on the inner side of the wheel mounting flange in advance by hot forging, and then cold-rolled. The method for manufacturing a wheel bearing device according to claim 1, wherein a portion corresponding to the outer rolling surface on the outer side is enlarged.   The cold rolling forming jig is composed of an outer roller disposed on the outer diameter side of the outer member and an inner roller disposed on the inner diameter side, and the outer roller is an annular recess of the outer member. In the state where the inner roller is formed in the shape of the outer surface of the double row, and the outer roller is pressed against the outer diameter of the outer member. The method for manufacturing a wheel bearing device according to claim 9, wherein the outer member is rolled while the inner roller is eccentric to the outer roller side.

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