JP2008126915A - Heat treatment method of outer member in bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment method of an outer member in a bearing device for a wheel capable of forming a consistently hardened layer by induction hardening. <P>SOLUTION: A heating unit 21 integrally has annular high frequency heating coils 21a, 21b corresponding to double-row outer rolling surfaces 2a, 2b, and a coil 21c for a shoulder arranged therebetween. The difference between outside diameters Dc1, Dc2 is set to be identical to the difference between groove diameters d1, d2. The outside diameter Dc2 of the induction heating coil 21b corresponding to the outer rolling surface 2b on the inner side is set to be smaller than the inside diameter ds of a shoulder 18. When the heating unit 21 is inserted from the outer side of an outer member 2, and the axis of the heating unit 21 is matched, the induction heating coils 21a, 21b are arranged facing the double-row outer rolling surfaces 2a, 2b and conducted, the heating unit 21 is turned around the axis, and simultaneously hardened by cooling water 25 ejected from a cooling nozzle 22 to continuously form a predetermined hardened layer 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an outer member in a wheel bearing device, and more particularly to a heat treatment method for an outer member in a wheel bearing device that enables formation of a stable hardened layer by induction hardening.

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

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

  In such a wheel bearing device composed of double-row rolling bearings, the left and right rows of bearings have the same specifications so far. Absent. That is, the position of the vehicle weight when stationary is determined so that it acts on the approximate center of the double row rolling bearing, but when turning, the opposite side of the turning direction (when turning right, the vehicle A large radial load or axial load is applied to the left axle. Therefore, at the time of turning, it is effective to increase the rigidity of the outer bearing row rather than the inner bearing row. Therefore, a wheel bearing device shown in FIG. 3 is known as a wheel bearing device that achieves high rigidity without increasing the size of the device.

  This wheel bearing device 50 has a vehicle body mounting flange 51c integrally attached to a knuckle (not shown) on the outer periphery, and an outer side in which double row outer rolling surfaces 51a and 51b are formed on the inner periphery. A member 51 and a wheel mounting flange 53 for mounting a wheel (not shown) at one end are integrally formed, and one inner rolling surface 52a facing the double row outer rolling surfaces 51a and 51b on the outer periphery. The hub wheel 52 formed with a small diameter step portion 52b extending in the axial direction from the inner rolling surface 52a and the small diameter step portion 52b of the hub wheel 52 are externally fitted to the double row outer rolling surface 51a, 51b. An inner member 55 composed of an inner ring 54 formed with the other inner rolling surface 54a facing each other, a double row of balls 56 and 57 accommodated between both the rolling surfaces, and these balls 56 and 57 Cages 58 and 5 that hold the roll freely. It is composed of a double row angular contact ball bearing with and.

  The inner ring 54 is fixed in the axial direction by a caulking portion 52c formed by plastically deforming a small diameter step portion 52b of the hub wheel 52 radially outward. Seals 60 and 61 are attached to the opening of the annular space formed between the outer member 51 and the inner member 55, leakage of the lubricating grease sealed inside the bearing, and rainwater from the outside into the bearing. And dust are prevented from entering.

Here, the pitch circle diameter D1 of the outer side balls 56 group is set larger than the pitch circle diameter D2 of the inner side balls 57 group. Along with this, the inner rolling surface 52a of the hub wheel 52 is expanded in diameter than the inner rolling surface 54a of the inner ring 54, and the outer rolling surface 51a on the outer side of the outer member 51 is also rolled on the inner side. The diameter is larger than that of the surface 51b. The outer side balls 56 are accommodated more than the inner side balls 57. As described above, by setting the pitch circle diameters D1 and D2 to D1> D2, the rigidity is improved not only when the vehicle is stationary but also when turning, and the life of the wheel bearing device 50 can be extended. it can.
JP 2004-108449 A

  In this type of conventional wheel bearing device 50, when forming a hardened layer on the double row outer raceway surfaces 51a, 51b of the outer member 51, it is performed by induction hardening as shown in FIG. That is, as shown in (a), the heating unit 62 integrally including the high-frequency heating coils 62a and 62a corresponding to the double row outer rolling surfaces 51a and 51b is inserted into the outer member 51, and (b) ), The high-frequency heating coils 62a, 62a are positioned on the double-row outer rolling surfaces 51a, 51b, and then the high-frequency heating coils 62a, 62a are energized to thereby energize the double-row outer rolling surfaces 51a, 51b is heated, and at the same time, the heating unit 62 is rotated around the axis. At this time, the cooling water 64 is ejected from the cooling nozzle 63 disposed radially outward of the outer member 51, and the heated double-row outer rolling surfaces 51a, 51b are sequentially and rapidly cooled. The predetermined hardened layer 66 is formed on the double row outer rolling surfaces 51a and 51b.

  However, in this conventional wheel bearing device 50, the pitch circle diameter D1 of the outer side balls 56 group is set larger than the pitch circle diameter D2 of the inner side balls 57 group, and accordingly, the outer member Since the outer rolling surface 51a on the outer side of 51 is larger in diameter than the outer rolling surface 51b on the inner side, uniform hardened layers 66 and 66 are formed on the double row outer rolling surfaces 51a and 51b. Is difficult. This is because, in order to avoid interference between the high-frequency heating coils 62a and 62a and the outer member 51, the outer diameter Dc of the high-frequency heating coils 62a and 62a is smaller than the inner diameter ds of the small-diameter shoulder 65 of the outer member 51. It must be formed. Therefore, when the specifications of the high-frequency heating coils 62a and 62a are set with reference to the outer side rolling surface 51b on the side having the smaller pitch circle diameter D2 (inner side), the outer side rolling surface on the side having the larger pitch circle diameter D1 (outer side). A large gap is generated between 51a and the high-frequency heating coil 62a, and a large electric power is required to form the predetermined hardened layer 66 on the outer rolling surface 51a. This not only increases the manufacturing cost, but also makes it difficult to efficiently form a stable hardened layer 66, and there is a risk of uneven burning and cracking due to local overheating.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for heat-treating an outer member in a wheel bearing device that can form a stable hardened layer by induction hardening.

  In order to achieve the object, the invention according to claim 1 of the present invention is such that an outer member having a double row outer rolling surface formed on the inner periphery and an outer member facing the double row outer rolling surface on the outer periphery. An inner member provided with a double-row inner rolling surface, and a double-row rolling element group that is slidably accommodated between both inner and outer rolling surfaces of the inner member, In the wheel bearing device in which the pitch circle diameter of the outer side rolling element group of the double row rolling element group is set to be larger than the pitch circle diameter of the inner side rolling element group, A heat treatment method for forming a predetermined hardened layer on the outer rolling surface of a row, the two annular high-frequency heating coils corresponding to the outer rolling surface of the double row, and disposed between these high-frequency heating coils A heating part integrally having a shoulder coil, and the axial center of the outer part coincides with the heating part. The high-frequency heating coil is disposed to face the outer rolling surface of the double row through a predetermined air gap, and the difference in the outer diameter of the high-frequency heating coil is a difference in the groove diameter of the outer rolling surface of the double row. Are set to be the same.

  Thus, in the wheel bearing device in which the pitch circle diameter of the outer side rolling element group is set larger than the pitch circle diameter of the inner side rolling element group, the double row outer rolling surface of the outer member A heat treatment method for forming a predetermined hardened layer, comprising: two annular high-frequency heating coils corresponding to double-row outer rolling surfaces; and a shoulder coil disposed between the high-frequency heating coils. A heating unit having a single unit is provided, and a high-frequency heating coil is disposed to face the outer rolling surface of the double row through a predetermined air gap in a state where the axis of the heating unit and the outer member coincide with each other. Since the difference in the outer diameter of the coils is set to be the same as the difference in the groove diameters of the outer rolling surfaces of the double row, even if the outer rolling surfaces of the double row have different pitch circle diameters, A predetermined air gap is ensured between the rolling surface and the high-frequency heating coil. Is, it is possible to form it is induction hardened by a suitable power power, efficiently predetermined hardened layer to prevent the baked unevenness and quenching cracks due to local overheating occurs. Therefore, it is possible to provide a method for heat-treating the outer member in the wheel bearing device that can stably form a continuous hardened layer from the outer rolling surface to the shoulder.

  Preferably, as in the invention described in claim 2, the outer diameter of the high-frequency heating coil corresponding to the inner side outer rolling surface of the high-frequency heating coil is set smaller than the inner diameter of the inner shoulder portion. In addition, if the heating unit is inserted from the outer side of the outer member, the high-frequency heating coil can be positioned without interfering with the outer member, and a stable hardened layer can be formed.

  According to a third aspect of the present invention, there is provided a receiving jig in which the inner side end face of the outer member is abutted with a disc-shaped holding jig and an inrow portion is formed on the inner diameter portion. If the outer member is brought into contact with the outer end surface of the outer member and the outer member is held by the holding jig and the receiving jig, the outer member can be accurately positioned. .

  According to a fourth aspect of the present invention, while the high-frequency heating coil is energized in a state of being disposed opposite to the outer rolling surface of the double row, the heating unit is rotated about the axis at the same time. If the substantially entire outer periphery of the outer member is cooled and simultaneously quenched by cooling water ejected from the cooling nozzle, a predetermined hardened layer can be stably formed.

  The heat treatment method of the outer member in the wheel bearing device according to the present invention includes an outer member having a double-row outer rolling surface formed on the inner periphery, and a plurality of outer members facing the double-row outer rolling surface on the outer periphery. An inner member provided with an inner rolling surface of the row, and a double row rolling element group that is rotatably accommodated between both rolling surfaces of the inner member and the outer member. In the wheel bearing device in which the pitch circle diameter of the outer rolling element group among the rolling element groups in the row is set larger than the pitch circle diameter of the inner rolling element group, the double row of the outer members A heat treatment method for forming a predetermined hardened layer on an outer rolling surface, comprising two annular high-frequency heating coils corresponding to the double-row outer rolling surface, and a shoulder disposed between the high-frequency heating coils A heating unit integrally having a coil for a part, and the axial center of the heating unit and the outer member coincide with each other The high-frequency heating coil is disposed opposite to the outer rolling surface of the double row through a predetermined air gap, and the diameter difference of the outer diameter of the high-frequency heating coil is the groove diameter of the outer rolling surface of the double row. Since it is set to be the same as the difference, a predetermined air gap is secured between the outer rolling surface of the double row and the high-frequency heating coil even on the outer rolling surface of the double row having different pitch circle diameters. In addition to induction hardening with appropriate power, it is possible to efficiently form a predetermined hardened layer by preventing occurrence of uneven baking and cracking due to local overheating. Therefore, it is possible to provide a method for heat-treating the outer member in the wheel bearing device that can stably form a continuous hardened layer from the outer rolling surface to the shoulder.

  A body mounting flange for mounting to the knuckle on the outer periphery is integrated, an outer member with a double row outer raceway formed on the inner periphery, and a wheel mounting flange for mounting the wheel on one end is integrated. A hub wheel having one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, a small diameter step portion extending in the axial direction from the inner rolling surface, and a small diameter of the hub wheel An inner member consisting of an inner ring that is press-fitted into a stepped portion and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and both rolling of the inner member and the outer member A double row ball group accommodated in a rollable manner between the surfaces, and the pitch circle diameter of the outer side ball group of the double row ball group is larger than the pitch circle diameter of the inner side ball group In the wheel bearing device set in the above, the outer row double rolling of the outer member A heat treatment method for forming a predetermined hardened layer, wherein two annular high-frequency heating coils corresponding to the double-row outer rolling surface, and a shoulder coil disposed between the high-frequency heating coils, The high-frequency heating coil is disposed to face the outer rolling surface of the double row through a predetermined air gap in a state in which the heating unit and the axial center of the outer member coincide with each other. The difference in outer diameter of the high-frequency heating coil is set to be the same as the difference in groove diameter of the outer rolling surface of the double row, and the high-frequency heating coil corresponding to the outer rolling surface on the inner side of the high-frequency heating coil. When the outer diameter is set to be smaller than the inner diameter of the shoulder on the inner side, the heating unit is inserted from the outer side of the outer member, and then the high-frequency heating coil and the shoulder coil are energized. At the same time, the heating part While being rotated about a substantially entire periphery of the outer member by the cooling water released from the cooling nozzle are simultaneously hardened by being cooled.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a wheel bearing device according to the present invention, and FIG. 2 is an explanatory view showing a heat treatment method for the outer member of FIG.

  This wheel bearing device is for a driven wheel referred to as a third generation, and is a double row rolling element housed in a freely rollable manner between the inner member 1 and the outer member 2, and both members 1 and 2. (Ball) 3 and 4 groups. The inner member 1 includes a hub ring 5 and an inner ring 6 press-fitted into the hub ring 5 through a predetermined shimiro.

  The hub wheel 5 integrally has a wheel mounting flange 7 for attaching a wheel (not shown) to an end portion on the outer side, one (outer side) inner rolling surface 5a on the outer periphery, and this inner rolling. A small-diameter step portion 5b is formed through an axial portion 8 extending in the axial direction from the surface 5a. Hub bolts 7a are planted on the wheel mounting flange 7 in a circumferentially uniform manner, and circular holes 7b are formed between the hub bolts 7a. The circular hole 7b not only contributes to weight reduction, but also a fastening jig such as a wrench can be inserted from the circular hole 7b in the assembly / disassembly process of the apparatus, and the work can be simplified.

  The inner ring 6 is formed with the other (inner side) inner raceway surface 6a on the outer periphery and is press-fitted into the small-diameter stepped portion 5b of the hub wheel 5 to form a back-to-back type double row angular contact ball bearing. The end portion of 5b is fixed in the axial direction with a predetermined bearing preload applied by a caulking portion 5c formed by plastic deformation, thereby forming a so-called self-retain structure. The inner ring 6 and the rolling elements 3 and 4 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC up to the core portion by quenching.

  The hub wheel 5 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner raceway surface 5a and the base portion 7c on the inner side of the wheel mounting flange 7 to the small diameter step portion 5b. Thus, a predetermined curing treatment is applied to the surface hardness in the range of 58 to 64 HRC by induction hardening. The caulking portion 5c is kept in the surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 7, the fretting resistance of the small-diameter step portion 5b serving as the fitting portion of the inner ring 6 is improved, and the minute There is no occurrence of cracks and the like, and the plastic working of the caulking portion 5c can be performed smoothly.

  The outer member 2 integrally has a vehicle body mounting flange 2c to be attached to the knuckle 9 on the outer periphery, and an outer outer rolling surface 2a facing the inner rolling surface 5a of the hub wheel 5 on the inner periphery, An inner side outer rolling surface 2b facing the inner rolling surface 6a of the inner ring 6 is integrally formed. Double row rolling elements 3 and 4 are accommodated between these rolling surfaces and are held by the cages 10 and 11 so as to be freely rollable. A seal 12 and a slinger 13 are respectively attached to the opening of the annular space formed between the outer member 2 and the inner member 1, and leakage of grease sealed inside the bearing to the outside, Prevents rainwater and dust from entering the bearing.

  The outer member 2 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 2a and 2b have a surface hardness of 58 to 64HRC by induction hardening described later. A predetermined hardened layer 14 is formed in the range (indicated by cross hatching in the figure). In addition, although what was comprised by the double row angular contact ball bearing which used the ball for the rolling elements 3 and 4 was illustrated here, not only this but the double row tapered roller which used the tapered roller for the rolling elements 3 and 4 You may be comprised with the bearing. Further, the third generation structure on the driven wheel side is illustrated, but the first to fourth generation structures may be used regardless of the driven wheel side or the drive wheel side.

  In this embodiment, the pitch circle diameter PCDo of the outer side rolling element 3 group is set larger than the pitch circle diameter PCDi of the inner side rolling element 4 group. The sizes of the double-row rolling elements 3 and 4 may be the same, but here, the size of the outer-side rolling elements 3 is set smaller than the size of the inner-side rolling elements 4, and the outer The number of the rolling elements 3 on the side is set larger than the number of the rolling elements 4 on the inner side. As a result, the bearing space can be effectively utilized to reduce the weight and size, and the bearing rigidity of the outer side portion can be increased compared to the inner side, so that the life of the bearing can be extended.

  The outer ring of the hub wheel 5 has a counter part 15 from the groove bottom part of the inner rolling surface 5a, a shoulder part 8b against which the inner ring 6 is abutted from the counter part 15 via the shaft-like part 8 and the tapered step part 8a. And it is formed in the shape following the small diameter step part 5b. Further, a mortar-shaped recess 16 extending in the axial direction is formed at the outer side end of the hub wheel 5. The recess 16 is formed by forging, and the depth is at least near the groove bottom of the inner rolling surface 5a on the outer side. The recess 16 is formed along the outer shape of the hub wheel 5, and the hub The outer wall side of the ring 5 is formed to be substantially uniform.

  On the other hand, in the outer member 2, the outer side outer rolling surface 2a is formed with a larger diameter than the inner side outer rolling surface 2b due to the difference in pitch circle diameters PCDo and PCDi, and the outer side outer rolling surface 2b is formed. An annular recess 19 for weight reduction is formed between the shoulder portion 17 of the running surface 2a and the shoulder portion 18 of the outer side rolling surface 2b on the inner side which is the small diameter side.

  Here, a predetermined hardened layer 14 is formed on the double row outer rolling surfaces 2a, 2b of the outer member 2 by a heat treatment apparatus 20 as shown in FIG. The heat treatment apparatus 20 includes a heating unit 21, a cooling nozzle 22, and a disk-shaped pressing jig 23 and a receiving jig 24 that position and hold the outer member 2. The heating unit 21 has two annular high-frequency heating coils 21a and 21b corresponding to the double-row outer rolling surfaces 2a and 2b, shoulder portions 17 and 18 and a shoulder coil 21c corresponding to the recess 19 integrally. is doing. The diameter difference between the outer diameters Dc1 and Dc2 of the high-frequency heating coils 21a and 21b is set to be the same as the diameter difference between the groove diameters d1 and d2 of the double row outer rolling surfaces 2a and 2b. Furthermore, the outer diameter Dc2 of the high-frequency heating coil 21b corresponding to the inner-side outer rolling surface 2b of the high-frequency heating coils 21a and 21b is set to be smaller than the inner diameter ds of the shoulder 18 on the smaller-diameter side (Dc2 < ds). The cooling nozzle 22 is formed with a plurality of ejection holes 22 a for ejecting the cooling water 25 over substantially the entire outer peripheral surface of the outer member 2.

Next, the heat processing method of the double row outer side rolling surfaces 2a and 2b in the outer member 2 is demonstrated using FIG.
First, as shown in (a), the end face Fb on the inner side of the outer member 2 is brought into contact with the holding jig 23 so that the outer side rolling surface 2b on the inner side (small diameter side) is arranged on the back side. At the same time, the receiving jig 24 on which the in-row portion 24 a for axial alignment is formed is brought into contact with the outer end face Fa of the outer member 2, and the outer member 2 is moved by the holding jig 23 and the receiving jig 24. Positioning and holding is performed in a sandwiched state. And the heating part 21 is inserted from the outer side of the outer member 2 in a state where the outer member 2 and the axial center coincide with each other, and the high-frequency heating coil 21a is disposed in the vicinity thereof along the double row outer rolling surfaces 2a, 2b. , 21b are arranged opposite to each other through a predetermined air gap.

  Thereafter, as shown in (b), the high-frequency heating coils 21a and 21b and the shoulder coil 21c arranged opposite to the double row outer rolling surfaces 2a and 2b, the shoulders 17 and 18 and the recess 19 are energized. At the same time, by rotating the heating part 21 around the axis, the double-row outer rolling surfaces 2a, 2b, the shoulders 17, 18 and the entire recess 19 are simultaneously induction-heated, and the ejection holes of the cooling nozzle 22 The entire outer periphery of the outer member 2 is cooled by the cooling water 25 ejected from 22a and simultaneously hardened, and a predetermined hardened layer 14 is formed.

  As described above, in this embodiment, the annular high-frequency heating coils 21a and 21b and the shoulder coil corresponding to the outer rolling surfaces 2a and 2b of the double row of the outer member 2 and the shoulders 17 and 18 and the recess 19 are provided. A predetermined outer diameter provided with a heating part 21 integrally having 21c, wherein the high frequency heating coils 21a, 21b are opposed to the groove diameters d1, d2 of the double row outer rolling surfaces 2a, 2b via a predetermined air gap. The outer diameter Dc2 of the high frequency heating coil 21b formed on Dc1 and Dc2 and corresponding to the outer rolling surface 2b on the smaller diameter side of the high frequency heating coils 21a and 21b is set smaller than the inner diameter ds of the shoulder 18 on the smaller diameter side. At the same time, the heating unit 21 is inserted from the outer side of the outer member 2 in a state where the axial center of the outer member 2 coincides. Thereafter, the high-frequency heating coils 21a and 21b and the shoulder coil 21c are energized, and at the same time, the heating unit 21 is rotated around the axis, and the cooling water 25 ejected from the cooling nozzle 22 is applied to almost the entire outer periphery of the outer member 2. Are cooled and co-quenched, and a predetermined hardened layer 14 is continuously formed on the double row outer rolling surfaces 21a, 21b, the shoulders 17, 18 and the recess 19.

  Through these steps, even if the double-row outer rolling surfaces 2a and 2b have a groove diameter difference due to the difference in pitch circle diameter, these double-row outer rolling surfaces 2a and 2b and the high-frequency heating coils 21a and 21b. A predetermined air gap is secured between the two and induction hardening can be performed with appropriate power. Accordingly, it is possible to prevent the occurrence of uneven baking and cracking due to local overheating and to efficiently form the predetermined hardened layer 14, and continuously from the outer rolling surfaces 2 a and 2 b to the shoulder portions 17 and 18. It is possible to provide a heat treatment method for the outer member 2 in the wheel bearing device that can form the hardened layer 14.

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

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

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is explanatory drawing which shows the heat processing method of the outer member of FIG. 1, (a) has shown the insertion state of the heating part, (b) has shown the quenching state. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus. It is explanatory drawing which shows the heat processing method of the outer member of FIG. 3, (a) has shown the insertion state of the heating part, (b) has shown the quenching state.

Explanation of symbols

1 .... Inner member 2 ... Outer member 2a, 2b ... Outer rolling surface 2c ... ... Car body mounting flanges 3, 4 ... Rolling elements 5 ... Hub wheels 5a, 6a ... Inner rolling surface 5b ... Small diameter step 5c ... Clamping part 6 ... Inner ring 7 ... ... Wheel mounting flange 7a ... Hub bolt 7b ... Round hole 7c ... Base 8 ... ... Shaft 8a ... Steps 8b, 17, 18 ... Shoulder 9 ... Knuckle 10, 11, ...・ ・ ・ ・ ・ Retainer 12 ・ ・ ・ ・ ・ Seal 13 ・ ・ ・ ・ ・ Slinger 14 ············································································ 20... Heat treatment device 21... Heating parts 21 a and 21 b... High frequency heating coil 21 c. Coil 22 ... Cooling nozzle 22a ... Ejection hole 23 ... Holding jig 24 ... · Receiving jig 24a · · · Inrow 25 · · · Cooling water 50 · · · Wheel bearing device 51 · · · ... outer member 51a ... outer rolling surface 51b on the outer side ... outer rolling surface 51c on the inner side ... ..Car body mounting flange 52 ... Hub wheels 52a, 54a ... Inner rolling surface 52b ... Small diameter step 52c ... Clamping part 53 ... .... Wheel mounting flange 54 ... Inner ring 55 ... Inner members 56, 57 ... Balls 58, 59 ... .... Retainer 60, 61 ... Seal 62 ... Heating part 62a ... High frequency heating coil 63 ... ... Cooling nozzle 64 ... Cooling water 65 ... Shoulder 66 ... Hardened layer D1 ... .... Pitch circle diameter D2 of outer side ball ... Pitch circle diameter d1 of inner side ball ... Outer roll of outer side Running surface groove diameter d2 ... ..... groove diameter ds of inner side outer rolling surface ... shoulder inner diameter Dc1 ... of outer side high frequency heating coil Outer diameter Dc2 ... Outer diameter Fa of the inner side high-frequency heating coil ... Outer end face Fb of the outer member ... .... Inner side end face PCDo of outer member ... Pitch circle diameter PCDi of outer side rolling element group ... Pitch circle diameter of inner side rolling element group

Claims (4)

An outer member having a double row outer raceway formed on the inner periphery;
An inner member provided on the outer periphery with a double-row inner rolling surface facing the double-row outer rolling surface;
A double row rolling element group accommodated so as to be freely rollable between both rolling surfaces of the inner member and the outer member,
In the wheel bearing device in which the pitch circle diameter of the outer side rolling element group of the double row rolling element group is set to be larger than the pitch circle diameter of the inner side rolling element group, A heat treatment method for forming a predetermined hardened layer on the outer rolling surface of the row,
A heating unit integrally including two annular high-frequency heating coils corresponding to the double-row outer rolling surface and a shoulder coil disposed between the high-frequency heating coils; The high-frequency heating coil is disposed opposite to the outer rolling surface of the double row through a predetermined air gap in a state where the axial centers of the members coincide with each other, and the difference in outer diameter of the high-frequency heating coil is the double row. A heat treatment method for an outer member in a wheel bearing device, characterized in that it is set to be the same as the difference in groove diameter of the outer rolling surface.   The outer diameter of the high-frequency heating coil corresponding to the outer rolling surface on the inner side of the high-frequency heating coil is set to be smaller than the inner diameter of the shoulder on the inner side, and the heating portion is on the outer side of the outer member. The heat processing method of the outer member in the wheel bearing apparatus of Claim 1 inserted from.   The end surface on the inner side of the outer member is abutted with a disc-shaped holding jig, and a receiving jig in which an in-row portion is formed on the inner diameter portion is brought into contact with the end surface on the outer side of the outer member, The heat treatment method for the outer member in the wheel bearing device according to claim 1 or 2, wherein the outer member is held by the holding jig and the receiving jig.   While the high-frequency heating coil is energized in a state of being arranged opposite to the outer surface of the double row, the heating unit is rotated about the axis and the outer side is cooled by cooling water ejected from a cooling nozzle. The method of heat-treating an outer member in a wheel bearing device according to any one of claims 1 to 3, wherein substantially the entire outer periphery of the member is cooled and simultaneously quenched.

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