JP2012228696A - Shaft member of rolling bearing device for wheel and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing a cold forging having a fitting shaft part, a flange part, and a shaft part from a cylindrical material in a cold forging process, and to provide a shaft member of a rolling bearing device for a wheel, produced by the same.SOLUTION: This shaft member 1 of the rolling bearing device for the wheel is coaxially disposed with the fitting shaft part 30, the flange part 21, and the shaft part 10 along the shaft direction. The fitting shaft part has a cylindrical shape having a recessed part 35 opening in the shaft direction, the flange part has a disk shape perpendicular to the shaft direction, and the shaft part has a cylindrical shape and is formed with an inner ring raceway track face on the outer circumferential face. In the method for producing the shaft member 1 of the rolling bearing device for the wheel, by use of a cylindrical shaft-like material 62 having an outside diameter corresponding to the outside diameter of the fitting shaft part 30 in the shaft member 1 of the rolling bearing device for the wheel, the cold forging 64 integrally having the fitting shaft part, the flange part, and the shaft part is formed in double lateral extruding and one-time forward extruding of the cold forging process.

Description

  The present invention relates to a shaft member of a rolling bearing device for a wheel and a manufacturing method thereof.

A shaft member of a wheel rolling bearing device as a hub wheel used in a wheel rolling bearing device and a method of manufacturing the shaft member of the wheel rolling bearing device are disclosed in Patent Document 1, for example.
In addition, as for the shaft member of the rolling bearing device for wheels, the fitting shaft portion, the flange portion, and the shaft portion are arranged coaxially along the axial direction. The shaft portion is formed with a large-diameter shaft portion having a large diameter on the side close to the flange portion, and a small-diameter shaft portion having a small diameter on the side far from the flange portion.
In the manufacturing method of the shaft member of the conventional rolling bearing device for a wheel disclosed in Patent Document 1, a material having at least a large-diameter shaft portion is used, and the receiving side has an inner diameter that matches the outer diameter of the small-diameter shaft portion. The tip of the large-diameter shaft portion of the material is abutted against the punch, and the tip of the large-diameter shaft portion is pushed into the receiving punch by forward extrusion of cold forging to form a small-diameter shaft portion.

JP 2007-152413 A

  The prior art described in Patent Document 1 includes a forward extrusion process in which the tip of the large-diameter shaft portion is pushed into the receiving punch in the cold forging process to form a small-diameter shaft portion, and the outer diameter is smaller than the outer diameter of the flange portion. From a cylindrical material having a diameter, through a cold forging process 4 times or more as shown in the figure (forward extrusion and side extrusion multiple times), fitting shaft part, flange part The cold forging product provided with the shaft portion is formed, and the processing efficiency is not good. In addition, a die for each process is required, which increases processing equipment, processing time, and processing costs.

  The present invention was devised in view of such points, and efficiently produces a cold forged product having a fitting shaft portion, a flange portion, and a shaft portion from a cylindrical material in a cold forging process. And a shaft member of a rolling bearing device for a wheel manufactured by the manufacturing method.

In order to solve the above problems, the shaft member of the wheel rolling bearing device according to the present invention and the manufacturing method thereof take the following means.
A first aspect of the present invention is a method for manufacturing a shaft member of a wheel rolling bearing device in which a fitting shaft portion, a flange portion, and a shaft portion are arranged coaxially along the axial direction.
The fitting shaft portion has a cylindrical shape having a recess opening in the axial direction, the flange portion has a disk shape orthogonal to the axial direction, and a flange diameter that is a diameter in a direction orthogonal to the axial direction in the flange portion. Is larger than a fitting shaft portion diameter which is a diameter in a direction perpendicular to the axial direction of the fitting shaft portion, the shaft portion is cylindrical, and an inner ring raceway surface is formed on the outer peripheral surface, The shaft member of the wheel rolling bearing device is manufactured by cold forging.
First, a cylindrical shaft-shaped material having an outer diameter corresponding to the outer diameter of the fitting shaft portion is used, and the diameter of one end portion in the axial direction of the shaft-shaped material in the first cold forging step is The first lateral extrusion is performed so as to form an intermediate diameter flange portion that is an intermediate diameter flange portion that is larger than the fitting shaft portion diameter and smaller than the flange diameter.
Further, in the second cold forging step, the second side extrusion is performed until the diameter of the intermediate flange portion becomes the flange diameter.
Then, in the third cold forging step, forward extrusion is performed so as to form the concave portion and the shaft portion of the fitting shaft portion from the other end portion in the axial direction of the shaft-shaped material, and the wheel A shaft member of the rolling bearing device is formed.

  According to the first aspect of the invention, by using a cylindrical shaft-shaped material having an outer diameter corresponding to the outer diameter of the fitting shaft portion, the cold forging process is performed by two side extrusion processes, The forward forging process can be performed once, and a cold forged product having a shaft portion, a flange portion, and a fitting shaft portion integrally can be efficiently formed.

Next, 2nd invention of this invention is a manufacturing method of the shaft member of the rolling bearing apparatus for wheels which concerns on the said 1st invention, Comprising: Said 1st side extrusion in a said 1st cold forging process In the processing, a first one-side mold formed in the shape of the outer peripheral surface of the intermediate-diameter flange portion and the shape of the one-side intermediate-diameter flange surface that is a surface on the shaft portion side in the intermediate-diameter flange portion And the shape of the other-side intermediate-diameter flange surface that is the surface on the side of the fitting shaft portion in the intermediate-diameter flange portion and the shape of the outer peripheral surface of the fitting shaft portion, and the intermediate-diameter flange portion The first intermediate metal having a substantially cylindrical shape that has an outer diameter corresponding to the outer diameter of the fitting shaft portion and has a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion and is fitted to the first one-side mold. The mold can be fitted into the hollow portion of the first intermediate mold having a substantially cylindrical shape, and the front A first cylindrical mold having a substantially cylindrical shape having an outer diameter corresponding to the outer diameter of the fitting shaft portion, and lateral extrusion using the shaft-shaped material to the outer peripheral surface of the fitting shaft portion; Then, a primary cold forged product is formed in which the outer peripheral surface of the intermediate diameter flange portion, the one side intermediate diameter flange surface, and the other side intermediate diameter flange surface are formed.
Furthermore, in the second side extruding process in the second cold forging step, the shape of the outer peripheral surface of the flange portion and the shape of the one side flange surface that is the surface of the flange portion on the side of the shaft portion. And a second one-side mold formed on the flange portion, a shape of the other flange surface which is a surface of the flange portion on the fitting shaft portion side, and a shape of the outer peripheral surface of the fitting shaft portion. A substantially cylindrical shape that has an outer diameter corresponding to the outer diameter of the flange portion and has a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion and is fitted to the second one-side mold. The second intermediate mold having a substantially cylindrical shape that can be fitted into the hollow part of the second intermediate mold having a shape and the second intermediate mold having a substantially cylindrical shape and has an outer diameter corresponding to the outer diameter of the fitting shaft part. Side fitting using the other side mold, and fitting from the primary cold forged product And the outer peripheral surface of the parts to form the outer peripheral surface of the flange portion, and the one side flange surface, and the other side flange surface, the formed secondary cold forging.
In the forward extrusion process in the third cold forging step, the shape of the outer peripheral surface of the flange portion, the shape of the one side flange surface, and the shape of the shaft portion at the tip of the one side flange surface The outer diameter corresponding to the outer diameter of the flange portion is formed in the third one-side mold formed on the outer surface of the flange portion and the shape of the outer peripheral surface of the fitting shaft portion. A third cylindrical intermediate mold having a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion and fitting to the third one-side mold, and the substantially cylindrical first The second cold forging by using a third other mold that can be fitted in the cavity of the three intermediate molds and formed in the shape of the recess of the fitting shaft part. In a third cold forged product in which the concave portion of the fitting shaft portion and the shaft portion are formed from a product. That forms the shaft member of the wheel rolling bearing device.

  According to the second aspect of the present invention, the cold forging process is performed twice by using a cylindrical shaft-shaped material having an outer diameter corresponding to the outer diameter of the fitting shaft portion and an appropriate die. This can be realized by a one-side extrusion process and a single forward extrusion process, and a cold forged product having a shaft portion, a flange portion, and a fitting shaft portion integrally can be efficiently formed.

Next, a third invention of the present invention is a method of manufacturing a shaft member of a wheel rolling bearing device according to the second invention, wherein in the first cold forging step, the first intermediate mold is used. And side extruding using a first integrated mold in which the first intermediate mold and the first other mold are integrally formed instead of using the first other mold. In the primary cold, the outer peripheral surface of the fitting shaft portion, the outer peripheral surface of the intermediate-diameter flange portion, the one-side intermediate-diameter flange surface, and the other-side intermediate-diameter flange surface are formed from the shaft-shaped material. Form a forged product.
Alternatively, in the second cold forging step, instead of using the second intermediate mold and the second other mold, the second intermediate mold and the second other mold are integrally formed. By performing a side extrusion process using the formed second integrated mold, the outer peripheral surface of the fitting shaft portion, the outer peripheral surface of the flange portion, and the one-side flange surface from the primary cold forged product And a second cold forged product in which the other flange surface is formed.
Alternatively, in the third cold forging step, instead of using the third intermediate mold and the third other mold, the third intermediate mold and the third other mold are integrally formed. By performing forward extrusion using the formed third integrated die, the third cold forged product in which the concave portion of the fitting shaft portion and the shaft portion are formed from the secondary cold forged product. A shaft member of the rolling bearing device for a certain wheel is formed.

  According to the third aspect of the invention, the first integrated mold in which the first intermediate mold and the first other mold are integrally formed, or the second intermediate mold and the second other mold are integrally formed. By using the formed second integrated mold or the third integrated mold in which the third intermediate mold and the third other mold are integrally formed, a cold forged product can be formed more efficiently. it can.

Next, 4th invention of this invention is a manufacturing method of the shaft member of the rolling bearing device for wheels which concerns on the said 1st invention, Comprising: The said intermediate diameter flange part inclines in the side of the said fitting shaft part. An intermediate diameter inclined flange portion having a conical shape, and in the first side extrusion in the first cold forging step, the shape of the outer peripheral surface of the intermediate diameter inclined flange portion and the intermediate diameter inclined flange portion A fourth one-side mold formed in a conical one-side intermediate-diameter inclined flange surface that is a surface on the shaft portion side of the portion, and the fitting shaft portion in the intermediate-diameter inclined flange portion The outer surface corresponding to the outer diameter of the intermediate diameter inclined flange portion is formed in the shape of the conical other side intermediate diameter inclined flange surface and the shape of the outer peripheral surface of the fitting shaft portion. An inner diameter that has a diameter and corresponds to the outer diameter of the fitting shaft portion A substantially cylindrical fourth intermediate mold that has a cavity of the method and fits with the fourth one-side mold, and can fit into a cavity of the substantially cylindrical fourth intermediate mold A substantially cylindrical fourth mold on the other side having an outer diameter corresponding to the outer diameter of the fitting shaft portion, and an outer peripheral surface of the fitting shaft portion from the shaft-shaped material by side extrusion. And a primary cold forged product in which the outer peripheral surface of the intermediate diameter inclined flange portion, the one side intermediate diameter inclined flange surface, and the other side intermediate diameter inclined flange surface are formed.
Furthermore, in the second side extruding process in the second cold forging step, the shaft portion side of the inclined flange portion whose diameter is expanded from the intermediate diameter inclined flange portion to the final flange portion diameter. A first conical inclined flange surface and a shape of the outer peripheral surface of the inclined flange portion, a fifth one mold formed on the inclined flange portion, and the fitting shaft portion in the inclined flange portion And having an outer diameter corresponding to the outer diameter of the inclined flange portion, and the shape of the conical other side inclined flange surface and the shape of the outer peripheral surface of the fitting shaft portion. A substantially cylindrical fifth intermediate mold that has a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion and is fitted to the fifth one-side mold, and the substantially cylindrical fifth intermediate mold Fits into the cavity of the mold and corresponds to the outer diameter of the fitting shaft An outer surface of the fitting shaft portion from the first cold forged product, and an outer surface of the inclined flange portion. And a secondary cold forged product in which the one side inclined flange surface and the other side inclined flange surface are formed.
In the forward extrusion process in the third cold forging step, the shape of the outer peripheral surface of the flange portion, the shape of the one side flange surface, and the shape of the shaft portion at the tip of the one side flange surface The outer diameter corresponding to the outer diameter of the flange portion is formed in the shape of the sixth one-side mold, the shape of the other-side flange surface, and the shape of the outer peripheral surface of the fitting shaft portion. A substantially cylindrical sixth intermediate mold that has a hollow part having an inner diameter corresponding to the outer diameter of the fitting shaft part and is fitted to the sixth one-side mold, and the substantially cylindrical first part The second cold forging is forward-extruded using a sixth other mold that can be fitted into the cavity of the six intermediate molds and is formed in the shape of the recess of the fitting shaft part. The concave portion of the fitting shaft portion, the shaft portion, the outer peripheral surface of the flange portion, and the front On the other hand forming the lateral flange surface, and the other side flange surface, the shaft member of the wheel rolling bearing device is a third-order cold forgings are formed.

  According to the fourth aspect of the invention, the cold forging process is performed twice by using a cylindrical shaft-shaped material having an outer diameter corresponding to the outer diameter of the fitting shaft portion and an appropriate die. This can be realized by a one-side extrusion process and a single forward extrusion process, and a cold forged product having a shaft portion, a flange portion, and a fitting shaft portion integrally can be efficiently formed.

Next, a fifth invention of the present invention is a method of manufacturing a shaft member of a rolling bearing device for a wheel according to the fourth invention, wherein in the first cold forging step, the fourth intermediate mold And side extruding using a fourth integrated mold in which the fourth intermediate mold and the fourth other mold are integrally formed instead of using the fourth other mold. The one-side intermediate diameter inclined flange surface and the other inclined from the shaft-shaped material to the outer peripheral surface of the fitting shaft portion, the final one-side flange surface, and the final other-side flange surface. A primary cold forged product having a side intermediate diameter inclined flange surface is formed.
Alternatively, in the second cold forging step, instead of using the fifth intermediate mold and the fifth other mold, the fifth intermediate mold and the fifth other mold are integrally formed. By performing a side extrusion process using the formed fifth integrated die, the outer peripheral surface of the fitting shaft portion, the final one-side flange surface, and the final other side from the first cold forged product A secondary cold forging product is formed in which the one side inclined flange surface and the other side inclined flange surface inclined with respect to the side flange surface are formed.
Alternatively, in the third cold forging step, instead of using the sixth intermediate mold and the sixth other mold, the sixth intermediate mold and the sixth other mold are integrally formed. By performing forward extrusion using the formed sixth integrated mold, the concave portion of the fitting shaft portion, the shaft portion, the final one-side flange surface, and the final shape are obtained from the secondary cold forging product. A shaft member of the rolling bearing device for a wheel, which is a tertiary cold forged product on which the other side flange surface is formed, is formed.

  According to the fifth aspect of the invention, the fourth integrated mold in which the fourth intermediate mold and the fourth other mold are integrally formed, or the fifth intermediate mold and the fifth other mold are integrated. By using the formed fifth integrated mold or the sixth integrated mold in which the sixth intermediate mold and the sixth other mold are integrally formed, a cold forged product can be formed more efficiently. it can.

Next, 6th invention of this invention is a manufacturing method of the shaft member of the rolling bearing apparatus for wheels which concerns on any one of the said 1st invention-5th invention, Comprising: Said 1st cold Prior to the forging process, at least the annealing process and the coating process are performed on the shaft-shaped material in the first annealing / coating process.
In addition, after performing the first cold forging step and before the second cold forging step, at least annealing treatment and coating treatment are performed on the shaft-shaped material in the second annealing / coating step. Try again.

  According to the sixth aspect of the present invention, cold forging can be performed in the first cold forging step and the second cold forging step without causing cracks in the shaft-shaped material.

  Next, a seventh invention of the present invention is a rolling bearing device for a wheel manufactured by the method for manufacturing a shaft member of a rolling bearing device for a wheel according to any one of the first to sixth inventions. A circle member having an outer diameter corresponding to the outer diameter of the fitting shaft portion when the shaft member of the rolling bearing device for a wheel is formed in the first to third cold forging steps. It is manufactured from a columnar shaft-shaped material and has the disk-shaped flange portion.

  According to the seventh aspect of the invention, the cold forging process is performed by two lateral extrusion processes and one forward extrusion process using a cylindrical shaft-shaped material having an outer diameter corresponding to the outer diameter of the fitting shaft portion. The shaft member of the rolling bearing device for a wheel which is realized by processing and has a shaft portion, a flange portion, and a fitting shaft portion integrally and is efficiently formed can be realized.

It is an axial direction sectional view showing the state where shaft member 1 of the wheel rolling bearing device manufactured with the manufacturing method of the shaft member of the rolling bearing device for wheels of the present invention was assembled as rolling bearing device A for wheels. It is an axial sectional view of the shaft member 1 of the rolling bearing device for wheels. (A) is the figure which looked at the shaft member 1 of the rolling bearing device for wheels shown in FIG. 2 from the AA direction, (B) is the figure seen from the BB direction. It is a figure which shows the change of the shape of the raw material by the process (A)-process (I) until it forms the shaft member of the rolling bearing apparatus for wheels from the shaft-shaped raw material 60. In 1st Embodiment, it is a figure explaining two side extrusion processes of a cold forging process, and one front extrusion process, (A) is the metal and material of a first side extrusion process (B) shows a sectional view of the mold and material of the second side extrusion, and (C) shows a sectional view of the die and material of the forward extrusion process. Yes. (D) shows the schematic shape of the material before the first lateral extrusion, (E) shows the schematic shape of the material after the first lateral extrusion, and (F) shows 2 The schematic shape of the raw material after the second side extrusion is shown, and (G) shows the schematic shape of the raw material after forward extrusion. In 2nd Embodiment, it is a figure explaining two side extrusion processes and one front extrusion process of a cold forging process, (A) is the metal and material of a first side extrusion process (B) shows a sectional view of the mold and material of the second side extrusion, and (C) shows a sectional view of the die and material of the forward extrusion process. Yes. (D) shows the schematic shape of the material before the first lateral extrusion, (E) shows the schematic shape of the material after the first lateral extrusion, and (F) shows 2 The schematic shape of the raw material after the second side extrusion is shown, and (G) shows the schematic shape of the raw material after forward extrusion.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. FIG. 1 is an axial sectional view showing a state in which a shaft member 1 of a wheel rolling bearing device manufactured by the method for manufacturing a shaft member of a wheel rolling bearing device of the present invention is assembled as a wheel rolling bearing device A. Is shown. 2 shows an axial sectional view of the shaft member 1 of the wheel rolling bearing device, and FIG. 3 is a view (A) of the shaft member 1 of the wheel rolling bearing device shown in FIG. And the figure (B) seen from the BB direction is shown.

● [Whole rolling bearing device A and overall structure of shaft member 1 of wheel rolling bearing device (FIGS. 1 to 3)]
Next, the overall structure of the wheel rolling bearing device A and the shaft member 1 of the wheel rolling bearing device will be described with reference to FIGS.
As shown in FIGS. 1 and 2, a shaft member 1 (so-called hub wheel) of a wheel rolling bearing device employed in a wheel rolling bearing device A (so-called wheel hub unit) includes a shaft portion 10 and a flange portion. 21 and the fitting shaft portion 30 are integrally provided coaxially along the axial direction.
When the wheel rolling bearing device A is attached to the vehicle, the shaft portion 10 is located inside the vehicle, the fitting shaft portion 30 is located outside the vehicle, and in FIG. Indicates the inside of the vehicle, and the right direction of the page indicates the outside of the vehicle.

The shaft portion 10 has a substantially cylindrical shape, and a large-diameter shaft portion 11 having a large diameter is formed on a side near the flange portion 21 in the shaft portion 10, and an end portion far from the flange portion 21 is larger than the large-diameter shaft portion 11. A small-diameter shaft portion 12 having a small diameter is formed, and an inner ring abutting surface 12 a that is a surface orthogonal to the rotation axis of the shaft portion 10 is formed at a step portion between the large-diameter shaft portion 11 and the small-diameter shaft portion 12.
The flange portion 21 is located between the shaft portion 10 and the fitting shaft portion 30 and has a disk shape perpendicular to the axial direction (rotation axis ZS direction). The outer diameter of the flange portion 21 is the outer diameter of the shaft portion 10. It is larger than the diameter.
The fitting shaft portion 30 is formed on one end side of the shaft portion 10 (on the side opposite to the small-diameter shaft portion 12), is coaxially formed with the shaft portion 10 and is formed into a continuous, substantially cylindrical shape, and has a wheel (not shown). Center hole is fitted.
As shown in FIG. 3, a bolt hole 24 in which a hub bolt 27 for tightening a wheel is disposed by press-fitting is formed in the flange portion 21 extending in a disk shape in the outer diameter direction.
As shown in FIGS. 1 and 2, the fitting shaft portion 30 is formed with a brake rotor fitting portion 31 on the flange portion 21 side, and has a slightly smaller diameter wheel on the tip side than the brake rotor fitting portion 31. A fitting portion 32 is formed.
Further, as shown in FIG. 1, the surface around the center hole of the brake rotor 55 abuts on the rotor support surface 22 that is the surface of the flange portion 21 on the side of the fitting shaft portion 30.
A concave forged concave portion 35 is formed on the inner diameter side of the fitting shaft portion 30.

As shown in FIGS. 1 and 2, the large-diameter shaft portion 11 of the shaft portion 10 of the shaft member 1 of the rolling bearing device for a wheel described in the present embodiment has an outer periphery in the vicinity of the boundary portion with the flange portion 21. A first inner ring raceway surface 18 constituting one bearing portion of a double row angular ball bearing as a rolling bearing is formed on a part of the surface so as to be continuous in the circumferential direction.
Further, a seal surface 19 described later that is continuous in the circumferential direction is formed on a part of the outer peripheral surface adjacent to the first inner ring raceway surface 18 and close to the flange portion 21.
Further, an inner ring 42 having a second inner ring raceway surface 44 formed so as to be continuous in the circumferential direction is fitted on the outer circumferential surface of the small-diameter shaft portion 12. The inner ring 42 is fitted until it hits the inner ring abutting surface 12a.
And the protrusion part from the inner ring | wheel 42 in the small diameter shaft part 12 (shaft end part 15 in FIG. 1) is caulked radially outward to form a caulking part 17, and the caulking part 17 and the inner ring abutting surface 12a The inner ring 42 is fixed.
Further, as shown in FIG. 1, when the inner ring 42 is fixed with the caulking portion 17 and the inner ring abutting surface 12a by caulking the shaft end 15 of the small diameter shaft portion 12, the inner ring 42 has a strength capable of fixing. The area of the inner ring abutting surface 12a is set.

Moreover, as shown in FIG. 1, the outer ring | wheel 45 is arrange | positioned maintaining the annular space in the outer peripheral surface of the axial part 10 of the shaft member 1 of the rolling bearing apparatus for wheels.
On the inner peripheral surface of the outer ring 45, a first outer ring raceway surface 46 facing the first inner ring raceway surface 18 formed on the shaft member 1 of the wheel rolling bearing device, and a second inner ring formed on the inner ring 42. A second outer ring raceway surface 47 facing the raceway surface 44 is formed. Each inner ring raceway surface and each outer ring raceway surface are formed to be continuous in the circumferential direction on each surface.
Between the first inner ring raceway surface 18 and the first outer ring raceway surface 46, a plurality of first rolling elements 50 are held by a cage 52 and arranged so as to be able to roll. Between the two outer ring raceway surfaces 47, a plurality of second rolling elements 51 are held by a cage 53 and are arranged to be able to roll.
The plurality of first rolling elements 50 and the plurality of second rolling elements 51 are subjected to axial preload based on the caulking force when the caulking portion 17 is formed by caulking the end of the small diameter shaft portion 12. An angular ball bearing is provided.

As shown in FIG. 1, a vehicle body side flange 48 is integrally formed on the outer peripheral surface of the outer ring 45, and the vehicle body side flange is a knuckle, a carrier, etc. supported by a vehicle suspension device (not shown). Fastened to the mounting surface of the vehicle body side member with a bolt or the like.
A seal member 56 is press-fitted and assembled to the inner peripheral surface of the opening adjacent to the first outer ring raceway surface 46 in the outer ring 45, and the tip of the lip 58 of the seal member 56 is in sliding contact with the seal surface 19 ( The gap between the outer ring 45 and the shaft member 1 of the wheel rolling bearing device is sealed.
Further, as shown in FIGS. 3B and 2, the surface of the flange portion 21 on the side of the shaft portion 10 has a floating island shape in order to improve the rigidity around the bolt hole 24 while suppressing an increase in weight. A floating island-shaped thick portion 29 having a partial thickness is formed.

● [Manufacturing method of shaft member 1 of rolling bearing device for wheel (FIG. 4)]
Next, the manufacturing method of the shaft member 1 of the rolling bearing device for wheels is demonstrated using FIG.
4A to 4I show how the shaft member 1 of the rolling bearing device for a wheel is formed from the shaft-shaped material 60 through each process, and shows the cross-sectional shape of the material after each process.
The shaft member 1 of the rolling bearing device for a wheel described in the present embodiment includes a first annealing / coating process, a first cold forging process, a second annealing / coating process, and a second cold forging process. , Through a third cold forging process, a turning process, a heat treatment process, and a polishing process.
First, prior to the first annealing / coating process, a substantially cylindrical structural carbon steel having a carbon content of about 0.5% such as S45C, S50C, S55C, etc. is cut to a predetermined length to form a shaft-shaped material 60. (See FIG. 4A).
The outer diameter (φE) of the substantially cylindrical shaft-shaped material 60 is substantially the same as the outer diameter of the fitting shaft portion 30 of the shaft member 1 of the wheel rolling bearing device.

[First annealing / coating process (FIGS. 4B, 4C)]
In the first annealing / coating step, at least the following annealing treatment and coating treatment are performed.
In the annealing treatment, the shaft-shaped material 60 is heated at a temperature equal to or higher than the transformation point temperature (preferably, a temperature higher by about 20 ° C. to 70 ° C. than the transformation point temperature).
Thereby, the carbon component in the shaft-shaped material 60 is spheroidized and spheroidized and annealed to form the annealed shaft-shaped material 61 (see FIG. 4B). This annealed shaft material 61 improves the ductility of the material itself.

In the coating process, the surface of the annealed shaft material 61 is coated with a lubricant to form a coated shaft material 62 having the lubricant film 36 (see FIG. 4C).
For example, a coated shaft material 62 having a lubricant film (phosphate film) 36 is formed by applying phosphate as a lubricant to the surface of the annealed shaft material 61.
The coated shaft material 62 reduces the frictional force generated between the cold forging mold and the material (material) by the lubricant film 36 on the surface thereof.
In addition, after the above annealing treatment and before the above coating treatment, a shot blast treatment is performed, and when the surface of the annealed shaft material 61 is shaved and fine irregularities are formed so that the surface becomes rough, the coating treatment It is more preferable because a film can be formed more stably.

[First cold forging step (FIG. 4D)]
In the first cold forging process, the diameter of one end in the axial direction of the coated shaft material 62 is larger than the diameter (φE) of the fitting shaft portion 30 and the diameter (φG) of the flange portion 21. The first cold forging product 63 is formed by performing the first lateral extrusion so as to form an intermediate diameter flange portion 21Z that is a flange portion having an intermediate diameter (φF) that is a smaller diameter (FIG. 4). (See (D)).
In this way, the crack of the flange portion is prevented by expanding the diameter from the diameter (φE) of the fitting shaft portion 30 to the diameter (φG) of the flange portion 21 at a time without increasing the diameter to the intermediate diameter (φF). The occurrence of cracks and the like can be prevented appropriately.
The shape of the mold used in the first cold forging step will be described later.
In addition, the cross-sectional shape shown to FIG.4 (D)-(F) has shown the example of the cross-sectional shape in the case of 1st Embodiment mentioned later.

[Second annealing / coating process (FIG. 4E)]
In the second annealing / coating process, in order to expand the diameter of the intermediate diameter flange portion 21Z that has been expanded to the intermediate diameter (φF) to the final diameter (φG) of the flange portion 21 again, Similar to the annealing / coating process, at least the annealing process and the coating process are performed to form a primary cold forged product 64 that has been subjected to the annealing / coating process (see FIG. 4E).
As a result, the stress remaining in the material after the first cold forging is removed, and the ductility of the primary cold forged product 63 is improved and the friction coefficient is reduced again. Occurrence can be prevented appropriately.

[Second Cold Forging Process (FIG. 4F)]
In the second cold forging step, the diameter of one end portion in the axial direction in the annealed / coated primary cold forged product 64 is the final diameter of the flange portion 21 (φG). A second side extrusion process is performed to form a secondary cold forged product 65 (see FIG. 4F).
The shape of the mold used in the second cold forging step will be described later.

[Third cold forging step (FIG. 4G)]
In the third cold forging step, the large-diameter shaft portion 11 and the small-diameter shaft portion 12 are formed while forming the forged recess 35 on the end surface of the central portion of the fitting shaft portion 30 of the secondary cold forged product 65. A forward extrusion process is performed to form a third cold forged product 66 in which the fitting shaft portion 30, the flange portion 21, the large diameter shaft portion 11, and the small diameter shaft portion 12 are formed (see FIG. 4G).
Note that the cross-sectional shape shown in FIG. 4G is substantially the same in both a first embodiment and a second embodiment described later.
Further, the forward extrusion process refers to a process in which a material is placed inside a mold (so-called die), another mold (so-called punch) is pushed in, and the material is made to flow in the direction in which the mold is pushed.
Side extrusion is a direction in which a material is placed inside a die (so-called die), another die (so-called punch) is pushed in, and the direction in which the die is pushed in (mainly orthogonal) Refers to the process of making the material flow.

[Turning process (Fig. 4 (H))]
In the turning process, a part of the third cold forged product 66, for example, the rotor support surface 22 on one side of the flange portion 21 (corresponding to the other side flange surface 21C described later), and the end surface 33 of the fitting shaft portion 30 And the bolt hole 24 is drilled in the flange portion 21 to form a turned forged product 67 (see FIG. 4H).
In this turning process, the lubricant coating 36 of at least the wheel fitting portion 32 (see FIG. 2) of the fitting shaft portion 30 of the tertiary cold forged product 66 remains without turning.
In the present embodiment, as shown in FIG. 2, the lubricant coating 36 includes a surface on the opposite side of the rotor support surface 22 of the flange portion 21 (corresponding to a one-side flange surface 21D described later), a first inner ring raceway. The seal surface 19 formed adjacent to the shoulder portion of the surface 18, the surface of the forged recess 35, and the end surface of the shaft end portion 15 at the tip of the small diameter shaft portion 12 of the shaft portion 10 are left without being turned. .
Conventionally, at least the lubricant coating 36 of the wheel fitting portion 32 in FIG. 2 is turned, and in addition to the portions where the lubricant coating 36 is left in the prior art, at least lubrication of the wheel fitting portion 32 in the present application. Extra agent coating 36 is left.
Then, the turning range is reduced by the amount of the lubricant film 36 left, and the turning process is easy and takes a short time.

[Heat treatment process (FIG. 4I)]
Next, in the heat treatment step (quenching and tempering step), the first inner ring raceway surface 18 of the shaft portion 10 of the turned forged product 67 is induction-quenched and then tempered to form a heat-treated forged product 68 (FIG. 4). (See (I)). In this case, induction hardening is not performed on the seal surface 19, the outer peripheral surface of the small diameter shaft portion 12, and the inner ring abutting surface 12a. Thereby, the time of a heat treatment process can be shortened. As shown in FIG. 2, a hardened layer S is formed around the first inner ring raceway surface 18 by quenching and tempering.

[Polishing process]
In the polishing step, the first inner ring raceway surface 18 of the heat-treated forged product 68 is polished to form the shaft member 1 of the wheel rolling bearing device.

● [Details of Cold Forging Process in First Embodiment (FIG. 5)]
Next, details of the first cold forging process, the second cold forging process, and the third cold forging process in the first embodiment will be described with reference to FIG.
In the first embodiment, from the coated shaft-shaped material 62 (shaft-shaped material) having an outer diameter that is substantially the same (equal or slightly smaller) as the outer diameter (φE) of the final fitting shaft portion 30, A cold forged product having the fitting shaft portion 30, the flange portion 21, the large-diameter shaft portion 11, and the small-diameter shaft portion 12 integrally is formed through two side extrusion processes and one forward extrusion process.
5A shows a sectional view of the first side extrusion mold and material, and FIG. 5B shows a sectional view of the second side extrusion mold and material. FIG. 5C shows a cross-sectional view of a die and material for forward extrusion. FIG. 5D shows a schematic shape of the material before the first side extrusion, and FIG. 5E shows a schematic shape of the material after the first side extrusion. FIG. 5 (F) shows a schematic shape of the material after the second lateral extrusion, and FIG. 5 (G) shows a schematic shape of the material after the forward extrusion.
In addition, in the sectional view of the mold and the material for explaining the side extrusion process and the front extrusion process shown in FIGS. 5A to 5C, the right side of the drawing from the center line is the side extrusion process (or the front extrusion process). The state before performing (the state in which the material is set) is shown, and the left side of the paper from the center line shows the state where the side extrusion (or forward extrusion) has been completed.

Next, the shape and configuration of the mold in the first cold forging step (first lateral extrusion process), and materials before and after the cold forging, using FIGS. 5 (A), (D), and (E). The shape of will be described.
As shown in FIG. 5 (A), in the first cold forging step, a film-treated shaft using a first one-side mold K11, a first other-side mold K12, and a first intermediate mold K13. The material 62 is subjected to a side extrusion process.
The first one-side mold K11 is a flange portion having an intermediate diameter (φF) that is larger than the diameter (φE) of the fitting shaft portion 30 and smaller than the final diameter (φG) of the flange portion 21. It is formed in the shape of the outer peripheral surface in an intermediate diameter flange part, and the shape of the one side intermediate diameter flange surface 21B which is the surface by the side of the axial part 10 in an intermediate diameter flange part.
The first intermediate mold K13 is formed into a shape of the other-side intermediate diameter flange surface 21A that is a surface on the side of the fitting shaft portion 30 in the intermediate diameter flange portion and a shape of the outer peripheral surface of the fitting shaft portion 30. Yes. The first intermediate mold K13 has an outer diameter corresponding to the outer diameter of the intermediate diameter flange portion, and has a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion 30 at the center portion. It is formed in a substantially cylindrical shape that fits with the first one-side mold K11.
The first other mold K12 is formed in a substantially cylindrical shape that can be fitted into the cavity of the first intermediate mold K13 and has an outer diameter corresponding to the outer diameter of the fitting shaft part 30.
Then, the coated shaft material 62 (see FIG. 5 (D)) is disposed at the center portion of the first one-side mold K11 where the fitting shaft portion 30 is located, and the first intermediate mold K13 is lowered. The position of the outer peripheral surface of the fitting shaft portion 30 and the other-side intermediate diameter flange surface 21A is determined by fitting with the first one-side mold K11. Then, the outer peripheral surface of the fitting shaft portion 30 and the intermediate diameter flange portion are formed by lowering the first other side die K12 and fitting it into the cavity of the first intermediate die K13 to perform side extrusion. The primary cold forging product 63 (see FIG. 5E) in which the outer peripheral surface, the one-side intermediate diameter flange surface 21B, and the other-side intermediate diameter flange surface 21A are formed can be formed.
In order to prevent damage to the mold, the “volume of the space surrounded by the first one-side mold K11, the first intermediate mold K13, and the first other-side mold K12” is “the coating treatment. It is set to be larger than the “volume of the finished shaft material 62”.
When the inclination angle A in FIGS. 5A to 5C is set to 20 ° ≦ θ ≦ 60 °, the floating island-shaped thick portion 29 is formed on the one-side intermediate diameter flange surface 21B and the one-side flange surface 21D. In a portion that is not, it becomes closer to the inclination angle of the inclined portion where the thickness is gradually changed from the thick portion on the center side to the thin portion on the outer peripheral side, so that a more preferable shape can be formed.

Next, using FIG. 5 (B), (E), (F), the shape and configuration of the mold in the second cold forging step (second lateral extrusion process), and the material before and after the cold forging The shape of will be described.
As shown in FIG. 5B, in the second cold forging step, primary cold forging using the second one-side mold K21, the second other-side mold K22, and the second intermediate mold K23. The product 64 (the first cold forged product 63 after the second annealing / coating treatment) is subjected to side extrusion.
The second one-side mold K21 is formed in the shape of the outer peripheral surface of the final flange portion 21 and the shape of the one-side flange surface 21D that is the surface of the flange portion 21 on the shaft portion 10 side.
The second intermediate mold K <b> 23 is formed in the shape of the other flange surface 21 </ b> C that is the surface of the flange portion 21 on the fitting shaft portion 30 side and the shape of the outer peripheral surface of the fitting shaft portion 30. The second intermediate mold K23 has an outer diameter corresponding to the outer diameter of the flange portion 21 and a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion 30 at the center portion. It is formed in a substantially cylindrical shape that fits into the second one-side mold K21.
The second other mold K22 is formed in a substantially cylindrical shape that can be fitted into the cavity of the second intermediate mold K23 and has an outer diameter corresponding to the outer diameter of the fitting shaft part 30.
Then, the first cold forging product 63 is subjected to the second annealing / coating process described above, and the first cold forging product 64 after the annealing / coating treatment is arranged at the center of the second one-side mold K21. Then, the second intermediate mold K23 is lowered and fitted with the second one-side mold K21 to position the outer peripheral surface of the fitting shaft portion 30 and the other-side flange surface 21C. Then, by lowering the second other mold K22 and fitting it into the cavity of the second intermediate mold K23 and performing side extrusion, the outer peripheral surface of the fitting shaft part 30 and the flange part 21 A secondary cold forged product 65 (see FIG. 5F) in which the outer peripheral surface, the one side flange surface 21D, and the other side flange surface 21C are formed can be formed.
In order to prevent damage to the mold, the “volume of the space surrounded by the second one-side mold K21, the second intermediate mold K23, and the second other-side mold K22” It is set to be larger than the “volume of the primary cold forged product 64 after the coating process”.

Next, with reference to FIGS. 5C, 5 </ b> F, and 5 </ b> G, the shape and configuration of the mold in the third cold forging step (forward extrusion process) and the shape of the material before and after the cold forging will be described. To do.
As shown in FIG. 5C, in the third cold forging step, secondary cold forging is performed using the third one-side mold K31, the third other-side mold K32, and the third intermediate mold K33. Article 65 is forward extruded. Although the auxiliary mold K34 is also used in the present embodiment, the auxiliary mold K34 may be omitted.
The third one-side mold K31 includes a shape of the outer peripheral surface of the flange portion 21, a shape of the one-side flange surface 21D of the flange portion 21, and a shape and a small diameter of the large-diameter shaft portion 11 at the tip of the one-side flange surface 21D. It is formed in the shape of the shaft portion 12.
The auxiliary mold K34 is supported by the elastic body K34S with an elastic force applied to the tip of the small-diameter shaft portion of the third one-side mold K31, and is movable while supporting the extruded material. Since it moves to an appropriate position according to the variation in the volume of the material, it is possible to prevent the occurrence of burrs.
The third intermediate mold K33 is formed in the shape of the other flange surface 21C of the flange portion 21 and the shape of the outer peripheral surface of the fitting shaft portion 30. The third intermediate mold K33 has a cylindrical shape having the outer diameter of the flange portion 21, and has a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion 30 at the center portion. Fits into the mold K31.
The third other mold K32 is formed in a shape corresponding to the recess (forged recess 35) of the fitting shaft part 30, and the third other mold K32 is fitted into the cavity of the third intermediate mold K33. To do.
Then, the secondary cold forged product 65 is disposed in the third one-side mold K31, the third intermediate mold K33 is fitted into the third one-side mold K31, and the third other-side mold K32 is connected to the third one. By lowering into the hollow portion of the intermediate mold K33 and performing forward extrusion, the outer peripheral surface of the fitting shaft portion 30, the forged recess 35, the outer peripheral surface of the flange portion 21, the one side flange surface 21D, and the other side flange surface A tertiary cold forged product 66 in which 21C, the large-diameter shaft portion 11, and the small-diameter shaft portion 12 are formed can be formed.
The second annealing / coating performed between the first cold forging process and the second cold forging process between the second cold forging process and the third cold forging process. You may perform the process similar to a process.

In the above description, the example in which the first intermediate mold K13 and the first other mold K12 in FIG. 5A are configured separately is described. However, the first intermediate mold K13 and the first other mold A first integrated die that is a die integrated with the die K12 may be formed and used in the first cold forging step. In this case, the primary cold forged product can be formed more efficiently.
Further, the example in which the second intermediate mold K23 and the second other mold K22 in FIG. 5B are configured separately has been described. However, the second intermediate mold K23 and the second other mold K22 A second integrated die, which is a die integrated with each other, may be formed and used in the second cold forging step. In this case, a secondary cold forged product can be formed more efficiently.
Further, the example in which the third intermediate mold K33 and the third other mold K32 in FIG. 5C are configured separately has been described, but the third intermediate mold K33, the third other mold K32, A third integrated die that is a die integrated with each other may be formed and used in the third cold forging step. In this case, the third cold forged product can be formed more efficiently.

● [Details of Cold Forging Process in Second Embodiment (FIG. 6)]
Next, the details of the first to third cold forging processes in the second embodiment will be described with reference to FIG. In the second embodiment, compared to the first embodiment shown in FIG. 5, the intermediate diameter flange portion and the flange portion formed in the first cold forging step and the second cold forging step are extended. The difference is that the exit direction is inclined toward the fitting shaft portion 30 and that the mold has an inclined surface. Moreover, in the example of FIG. 6, the description of the floating island-shaped thick portion 29 of the flange portion 21 is omitted.
As in the first embodiment, the coated shaft material 62 (axial shape) having an outer diameter that is substantially the same (equal or slightly smaller) than the outer diameter (φE) of the final fitting shaft portion 30. Material) is subjected to two side extrusion processes and one forward extrusion process to obtain a cold forged product integrally having a fitting shaft part 30, a flange part 21, a large diameter shaft part 11, and a small diameter shaft part 12. Form.
6A shows a sectional view of the first side extrusion mold and material, and FIG. 6B shows a sectional view of the second side extrusion mold and material. FIG. 6 (C) shows a cross-sectional view of a die and material for forward extrusion. FIG. 6 (D) shows a schematic shape of the material before the first side extrusion, and FIG. 6 (E) shows a schematic shape of the material after the first side extrusion. FIG. 6 (F) shows a schematic shape of the material after the second lateral extrusion, and FIG. 6 (G) shows a schematic shape of the material after the forward extrusion.

Next, using FIG. 6 (A), (D), (E), the shape and configuration of the mold in the first cold forging step (first lateral extrusion), and the material before and after the cold forging The shape of will be described.
As shown in FIG. 6 (A), in the first cold forging step, a film-treated shaft shape using a fourth one-side mold K41, a fourth other-side mold K42, and a fourth intermediate mold K43. The material 62 is subjected to a side extrusion process.
The fourth one-side mold K41 has an intermediate diameter (φF) that is larger than the diameter (φE) of the fitting shaft portion 30 and smaller than the final diameter (φG) of the flange portion 21, and is fitted. The outer peripheral surface of the intermediate diameter inclined flange portion having a conical shape inclined acutely (inclination angle A [°]) toward the shaft portion 30 side, and the surface on the shaft portion 10 side in the intermediate diameter inclined flange portion. And a conical one side intermediate diameter inclined flange surface 21F.
The fourth intermediate mold K43 has a conical concentric shape on the other side intermediate diameter inclined flange surface 21E on the side of the fitting shaft portion 30 in the intermediate diameter inclined flange portion, and the shape of the outer peripheral surface of the fitting shaft portion 30. And is formed. The fourth intermediate mold K43 has an outer diameter (φF) corresponding to the outer diameter of the intermediate-diameter inclined flange portion, and has a cavity with an inner diameter dimension corresponding to the outer diameter of the fitting shaft portion 30 in the center portion. And has a substantially cylindrical shape that fits into the fourth one-side mold K41.
The fourth other mold K42 is formed in a substantially cylindrical shape that can be fitted into the cavity of the fourth intermediate mold K43 and has an outer diameter corresponding to the outer diameter of the fitting shaft part 30.
Then, the coated shaft material 62 (see FIG. 6D) is disposed at the center portion of the fourth one-side mold K41 where the fitting shaft portion 30 is located, and the fourth intermediate mold K43 is lowered. The position of the outer peripheral surface of the fitting shaft portion 30 and the other side intermediate diameter inclined flange surface 21E is determined by fitting with the fourth one side mold K41. Then, by lowering the fourth other side mold K42 and fitting it into the cavity of the fourth intermediate mold K43 and performing side extrusion processing, the outer peripheral surface of the fitting shaft part 30 and the intermediate diameter inclined flange A primary cold forged product 63 (see FIG. 6E) in which the one side intermediate diameter inclined flange surface 21F and the other side intermediate diameter inclined flange surface 21E are formed can be formed.
In order to prevent damage to the mold, etc., “the volume of the space surrounded by the fourth one-side mold K41, the fourth intermediate mold K43, and the fourth other-side mold K42” is “the coating treatment. It is set to be larger than the “volume of the finished shaft material 62”.
When the inclination angle A in FIGS. 6A to 6C is set to 20 ° ≦ θ ≦ 60 °, the one-side intermediate-diameter inclined flange surface 21F and the one-side inclined flange surface 21H (the floating island-shaped thick portion 29 (In the portion where the thickness is not formed) Since the inclination angle of the inclined portion where the thickness is gradually changed from the thick portion on the center side to the thin portion on the outer peripheral side becomes closer, it can be formed in a more preferable shape. .

Next, using FIG. 6 (B), (E), (F), the shape and configuration of the mold in the second cold forging step (second lateral extrusion process), and the material before and after the cold forging The shape of will be described.
As shown in FIG. 6B, in the second cold forging step, primary cold forging using the fifth one-side mold K51, the fifth other-side mold K52, and the fifth intermediate mold K53. The product 64 (the first cold forged product 63 after the second annealing / coating treatment) is subjected to side extrusion.
The fifth one-side mold K51 includes an outer peripheral surface of the inclined flange portion in which the diameter (φF) of the intermediate diameter inclined flange portion is increased to a diameter (φG ′) equivalent to the diameter (φG ′) of the final flange portion 21. The inclined flange portion is formed on the shaft 10 side surface of the inclined flange portion and a conical one-side inclined flange surface 21H.
The fifth intermediate die K53 is formed on the other side inclined flange surface 21G which is a conical shape on the side of the fitting shaft portion 30 in the inclined flange portion and the shape of the outer peripheral surface of the fitting shaft portion 30. Has been. The fifth intermediate mold K53 has an outer diameter (φG ′) corresponding to the outer diameter of the inclined flange portion, and a hollow portion having an inner diameter dimension corresponding to the outer diameter of the fitting shaft portion 30 at the center portion. And is formed in a substantially cylindrical shape that fits into the fifth one-side mold K51.
The fifth other mold K52 is formed in a substantially cylindrical shape that can be fitted into the cavity of the fifth intermediate mold K53 and has an outer diameter corresponding to the outer diameter of the fitting shaft part 30.
Then, the first cold forging product 63 is subjected to the second annealing / coating process described above, and the primary cold forging product 64 after the annealing / coating treatment is arranged in the center of the fifth one-side mold K51. Then, the fifth intermediate mold K53 is lowered and fitted with the fifth one-side mold K51 to position the outer peripheral surface of the fitting shaft portion 30 and the other-side inclined flange surface 21G. Then, by lowering the fifth other mold K52 and fitting it into the cavity of the fifth intermediate mold K53 and performing side extrusion, the outer peripheral surface of the fitting shaft part 30 and the one-side inclined flange A secondary cold forged product 65 (see FIG. 6F) in which the surface 21H and the other inclined flange surface 21G are formed can be formed.
In order to prevent damage to the mold, the “volume of the space surrounded by the fifth first mold K51, the fifth intermediate mold K53, and the fifth other mold K52” is more “secondary. It is set larger than the “volume of the cold forged product 65”.

Next, with reference to FIGS. 6C, 6 </ b> F, and 6 </ b> G, the shape and configuration of the mold in the third cold forging step (forward extrusion process) and the shape of the material before and after the cold forging will be described. To do.
As shown in FIG. 6C, in the third cold forging step, secondary cold forging is performed using the sixth one-side mold K61, the sixth other-side mold K62, and the sixth intermediate mold K63. Article 65 is forward extruded. Although the auxiliary mold K64 is also used in the present embodiment, the auxiliary mold K64 may be omitted.
The sixth one-side mold K61 and the auxiliary mold K64 in the second embodiment are the same as the third one-side mold K31 and the auxiliary mold K34 in the first embodiment, and the sixth one-side mold The mold K61 includes a shape of the outer peripheral surface of the flange portion 21, a shape of the one-side flange surface 21D of the flange portion 21, and a shape of the large-diameter shaft portion 11 and a shape of the small-diameter shaft portion 12 at the tip of the one-side flange surface 21D. And formed.
The auxiliary mold K64 is supported by the elastic body K64S with an elastic force applied to the tip of the small-diameter shaft portion of the sixth one-side mold K61, and is movable while supporting the extruded material. Since it moves to an appropriate position according to the variation in the volume of the material, it is possible to prevent the occurrence of burrs.
The sixth intermediate mold K63 and the sixth other mold K62 in the second embodiment are the same as the third intermediate mold K33 and the third other mold K32 in the first embodiment, and the The six intermediate mold K63 is formed in the shape of the other flange surface 21C of the flange portion 21 and the shape of the outer peripheral surface of the fitting shaft portion 30. The sixth other mold K62 is formed in the shape of the recess (forged recess 35) of the fitting shaft portion 30.
Then, the secondary cold forging product 65 is disposed in the sixth one-side mold K61, and the sixth intermediate mold K63 is fitted into the sixth one-side mold K61 and pushed in. The one side inclined flange surface 21H and the other side inclined flange surface 21G are formed on the final one side flange surface 21D and the final other side flange surface 21C. Then, by lowering the sixth other mold K62 into the cavity of the sixth intermediate mold K63 and performing forward extrusion processing, the outer peripheral surface of the fitting shaft portion 30, the forged recess 35, and the outer peripheral surface of the flange portion 21 The third cold forged product 66 in which the one-side flange surface 21D, the other-side flange surface 21C, the large-diameter shaft portion 11, and the small-diameter shaft portion 12 are formed can be formed.
The second annealing / coating performed between the first cold forging process and the second cold forging process between the second cold forging process and the third cold forging process. You may perform the process similar to a process.

In the above description, the example in which the fourth intermediate mold K43 and the fourth other mold K42 in FIG. 6A are configured separately has been described. However, the fourth intermediate mold K43 and the fourth other mold A fourth integrated die that is a die integrated with the die K42 may be formed and used in the first cold forging step. In this case, the primary cold forged product can be formed more efficiently.
Further, the example in which the fifth intermediate mold K53 and the fifth other mold K52 in FIG. 6B are configured separately has been described, but the fifth intermediate mold K53 and the fifth other mold K52 A fifth integrated die, which is a die integrated with each other, may be formed and used in the second cold forging step. In this case, a secondary cold forged product can be formed more efficiently.
Further, the example in which the sixth intermediate mold K63 and the sixth other mold K62 in FIG. 6C are configured separately has been described. However, the sixth intermediate mold K63, the sixth other mold K62, A sixth integrated die, which is a die integrated with, may be formed and used for the third cold forging step. In this case, the third cold forged product can be formed more efficiently.

In the method of manufacturing the shaft member of the wheel rolling bearing device described in the present embodiment, as described above, structural carbon steel such as S45C, S50C, and S55C is heated at a temperature equal to or higher than the transformation point temperature in the annealing process. Then, an annealed shaft-shaped material 61 is formed, and a lubricant film 36 is applied to the surface of the annealed shaft-shaped material 61 in the subsequent coating process to reduce the frictional force generated between the cold forging mold. The film-treated shaft-shaped material 62 is formed, and the material is excellent in forgeability.
Furthermore, by using the shaft-shaped raw material 60 having the outer diameter of the final fitting shaft portion 30, in the subsequent cold forging process, the primary cold forging process, the secondary cold forging process, and the tertiary cold forging. A cold forging product having a fitting shaft portion 30, a flange portion 21, a large-diameter shaft portion 11, and a small-diameter shaft portion 12 integrally by two lateral extrusion processes and one forward extrusion process ( The tertiary cold forging product 66) can be formed efficiently.
In the description of the present embodiment, at least the annealing treatment and the coating treatment are performed on the shaft-like material in the first annealing / coating step before the first cold forging step. In addition, after the first cold forging step and before the second cold forging step, at least annealing treatment and coating treatment were performed on the shaft-shaped material in the second annealing / coating step. However, the first annealing / coating process and the second annealing / coating process may be omitted.

The shaft member of the wheel rolling bearing device of the present invention and the manufacturing method thereof are not limited to the manufacturing method, process, process, etc., appearance, configuration, structure, etc. described in the present embodiment, and do not change the gist of the present invention. Various changes, additions and deletions can be made within the range.
The numerical values used in the description of the present embodiment are examples, and are not limited to these numerical values.
In the description of the present embodiment, an example in which the number of bolt holes 24 is four has been described. However, the number of bolt holes 24 is plural, and the number is not limited to four. Of course, the shape of the floating island-shaped thick portion 29 shown in FIG. 2B is also changed according to the number of the bolt holes 24.

DESCRIPTION OF SYMBOLS 1 Shaft member of rolling bearing apparatus for wheels 10 Shaft part 11 Large diameter shaft part 12 Small diameter shaft part 12a Inner ring abutting surface 15 Shaft end part 17 Caulking part 18 1st inner ring raceway surface 19 Sealing surface 21 Flange part 21A The other side intermediate diameter Flange surface 21B One side intermediate flange surface 21C The other side flange surface 21D One side flange surface 21E The other side intermediate diameter inclined flange surface 21F One side intermediate diameter inclined flange surface 21G The other side inclined flange surface 21H One side inclined flange surface 30 Fitting Shaft portion 35 Forged recess 36 Lubricant coating 42 Inner ring 44 Second inner ring raceway surface 45 Outer ring 46 First outer ring raceway surface 47 Second outer ring raceway surface 60 Shaft material 61 Annealed shaft material 62 Coated shaft material 63 1 Secondary cold forged product 64 Primary cold forged product (second annealing / coating process performed) 65 Secondary cold forged product 66 Third cold Structure 67 Turned forged product 68 Heat treated forged product A Rolling bearing device for wheels K11, K41 First one side mold K12, K42 First other side mold K13, K43 First intermediate mold K21, K51 Second one Side mold K22, K52 Second other mold K23, K53 Second intermediate mold K31, K61 Third one mold K32, K62 Third other mold K33, K63 Third intermediate mold K34, K64 Auxiliary Mold

Claims (7)

In the manufacturing method of the shaft member of the rolling bearing device for a wheel in which the fitting shaft portion, the flange portion, and the shaft portion are arranged coaxially along the axial direction.
The fitting shaft portion has a cylindrical shape having a recess opening in the axial direction;
The flange portion has a disk shape orthogonal to the axial direction,
A flange diameter that is a diameter in a direction orthogonal to the axial direction in the flange portion is larger than a fitting shaft portion diameter that is a diameter in a direction orthogonal to the axial direction in the fitting shaft portion,
The shaft portion has a cylindrical shape, and an outer ring surface is formed on the outer peripheral surface,
The shaft member of the rolling bearing device for wheels is manufactured by cold forging,
Using a cylindrical shaft-shaped material having an outer diameter corresponding to the outer diameter of the fitting shaft portion,
An intermediate diameter flange that is a flange portion having an intermediate diameter smaller than the fitting shaft diameter and having a diameter at one end in the axial direction of the shaft-shaped material in the first cold forging step Perform the first lateral extrusion to form the part,
In the second cold forging process, the second side extrusion is performed until the diameter of the intermediate flange portion becomes the flange diameter,
In the third cold forging step, forward extrusion is performed so as to form the concave portion and the shaft portion of the fitting shaft portion from the other axial end portion of the shaft-shaped material, and the wheel rolling Forming a shaft member of the bearing device;
Manufacturing method of shaft member of rolling bearing device for wheel. It is a manufacturing method of the shaft member of the rolling bearing device for wheels according to claim 1,
In the first lateral extrusion process in the first cold forging step,
A first one-side mold formed on the shape of the outer peripheral surface of the intermediate-diameter flange portion and the shape of the one-side intermediate-diameter flange surface that is the surface of the shaft portion side of the intermediate-diameter flange portion;
The intermediate-diameter flange portion is formed into a shape of the other-side intermediate-diameter flange surface, which is a surface on the fitting shaft portion side, and a shape of the outer peripheral surface of the fitting shaft portion, and is formed outside the intermediate-diameter flange portion. A first intermediate mold having a substantially cylindrical shape having an outer diameter corresponding to the diameter and having a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion and fitting to the first one-side mold; ,
A first cylindrical mold having a substantially cylindrical shape that can be fitted into a hollow portion of the first intermediate mold having a substantially cylindrical shape and has an outer diameter corresponding to the outer diameter of the fitting shaft portion; Side extrusion,
Primary cooling in which an outer peripheral surface of the fitting shaft portion, an outer peripheral surface of the intermediate-diameter flange portion, the one-side intermediate-diameter flange surface, and the other-side intermediate-diameter flange surface are formed from the shaft-shaped material. Forming a forged product,
In the second lateral extrusion process in the second cold forging step,
A second one-side mold formed on the shape of the outer peripheral surface of the flange portion and the shape of the one-side flange surface that is the surface of the flange portion on the side of the shaft portion;
An outer diameter corresponding to the outer diameter of the flange portion formed in the shape of the other side flange surface which is a surface of the flange portion on the side of the fitting shaft portion and the shape of the outer peripheral surface of the fitting shaft portion. A substantially cylindrical second intermediate mold that has a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion and is fitted to the second one-side mold,
A second cylindrical mold having a substantially cylindrical shape that can be fitted into a hollow portion of the second intermediate mold having a substantially cylindrical shape and has an outer diameter corresponding to the outer diameter of the fitting shaft portion; Side extrusion,
Secondary cold forged product in which the outer peripheral surface of the fitting shaft portion, the outer peripheral surface of the flange portion, the one side flange surface, and the other side flange surface are formed from the primary cold forged product. Form the
In the forward extrusion process in the third cold forging step,
A third one-side mold formed on the shape of the outer peripheral surface of the flange portion, the shape of the one-side flange surface, and the shape of the shaft portion at the tip of the one-side flange surface;
It is formed in the shape of the other side flange surface and the shape of the outer peripheral surface of the fitting shaft portion, has an outer diameter corresponding to the outer diameter of the flange portion, and corresponds to the outer diameter of the fitting shaft portion. A substantially cylindrical third intermediate mold having a hollow portion with an inner diameter dimension and fitted to the third one-side mold;
A third cylindrical mold that can be fitted into the hollow part of the third intermediate mold having a substantially cylindrical shape and that is formed in the shape of the concave part of the fitting shaft part, and is extruded forward,
Forming a shaft member of the rolling bearing device for a wheel, which is a tertiary cold forged product in which the recessed portion of the fitting shaft portion and the shaft portion are formed from the secondary cold forged product,
Manufacturing method of shaft member of rolling bearing device for wheel. It is a manufacturing method of the shaft member of the rolling bearing device for wheels according to claim 2,
In the first cold forging step, instead of using the first intermediate mold and the first other mold, the first intermediate mold and the first other mold are integrally formed. By performing side extrusion using the first integral mold, the outer peripheral surface of the fitting shaft portion, the outer peripheral surface of the intermediate flange portion, and the one intermediate flange surface from the shaft-shaped material Forming a primary cold forged product in which the other side intermediate diameter flange surface is formed;
Alternatively, in the second cold forging step, instead of using the second intermediate mold and the second other mold, the second intermediate mold and the second other mold are integrally formed. By performing a side extrusion process using the formed second integrated mold, the outer peripheral surface of the fitting shaft portion, the outer peripheral surface of the flange portion, and the one-side flange surface from the primary cold forged product And forming a secondary cold forged product in which the other flange surface is formed,
Alternatively, in the third cold forging step, instead of using the third intermediate mold and the third other mold, the third intermediate mold and the third other mold are integrally formed. By performing forward extrusion using the formed third integrated die, the third cold forged product in which the concave portion of the fitting shaft portion and the shaft portion are formed from the secondary cold forged product. Forming a shaft member of the wheel rolling bearing device;
Manufacturing method of shaft member of rolling bearing device for wheel. It is a manufacturing method of the shaft member of the rolling bearing device for wheels according to claim 1,
The intermediate diameter flange portion is an intermediate diameter inclined flange portion having a conical shape inclined toward the fitting shaft portion side,
In the first lateral extrusion process in the first cold forging step,
A shape of the outer peripheral surface of the intermediate diameter inclined flange portion and a shape of a conical one side intermediate diameter inclined flange surface which is a surface on the shaft portion side of the intermediate diameter inclined flange portion. One side mold,
The intermediate diameter inclined flange portion is a surface on the side of the fitting shaft portion, and is formed into a conical shape on the other side intermediate diameter inclined flange surface and a shape of the outer peripheral surface of the fitting shaft portion. A substantially cylindrical shape having an outer diameter corresponding to the outer diameter of the intermediate-diameter inclined flange portion and having a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion and fitting to the fourth one-side mold The fourth intermediate mold,
A substantially cylindrical fourth mold on the other side that can be fitted into the hollow portion of the fourth intermediate mold having a substantially cylindrical shape and has an outer diameter corresponding to the outer diameter of the fitting shaft part; Side extrusion,
An outer peripheral surface of the fitting shaft portion, an outer peripheral surface of the intermediate diameter inclined flange portion, the one intermediate diameter inclined flange surface, and the other intermediate diameter inclined flange surface are formed from the shaft-shaped material. Forming a primary cold forged product,
In the second lateral extrusion process in the second cold forging step,
The shape of the conical one side inclined flange surface, which is the surface on the shaft side in the inclined flange portion whose diameter is expanded from the intermediate diameter inclined flange portion to the diameter of the final flange portion, and the inclined flange portion A shape of the outer peripheral surface of the fifth one-side mold formed on,
A surface of the inclined flange portion on the side of the fitting shaft portion that is formed into a conical shape on the other side of the inclined flange surface and a shape of an outer peripheral surface of the fitting shaft portion. A fifth cylindrical intermediate mold having an outer diameter corresponding to the outer diameter and having a hollow portion having an inner diameter corresponding to the outer diameter of the fitting shaft portion and fitted to the fifth first mold. When,
A fifth cylindrical mold having a substantially cylindrical shape that can be fitted into a hollow portion of the fifth intermediate mold having a substantially cylindrical shape and has an outer diameter corresponding to the outer diameter of the fitting shaft portion; Side extrusion,
Secondary cooling in which an outer peripheral surface of the fitting shaft portion, an outer peripheral surface of the inclined flange portion, the one inclined flange surface, and the other inclined flange surface are formed from the first cold forged product. Forming a forged product,
In the forward extrusion process in the third cold forging step,
A sixth one-side mold formed on the shape of the outer peripheral surface of the flange portion, the shape of the one-side flange surface, and the shape of the shaft portion at the tip of the one-side flange surface;
It is formed in the shape of the other side flange surface and the shape of the outer peripheral surface of the fitting shaft portion, has an outer diameter corresponding to the outer diameter of the flange portion, and corresponds to the outer diameter of the fitting shaft portion. A substantially cylindrical sixth intermediate mold having a hollow portion with an inner diameter dimension and fitted to the sixth one-side mold;
A sixth cylindrical mold that can be fitted into the hollow portion of the sixth intermediate mold having a substantially cylindrical shape and that is formed in the shape of the concave portion of the fitting shaft part, and forward-extruding using,
A tertiary in which a concave portion of the fitting shaft portion, the shaft portion, an outer peripheral surface of the flange portion, the one side flange surface, and the other side flange surface are formed from the secondary cold forged product. Forming a shaft member of the rolling bearing device for wheels, which is a cold forged product,
Manufacturing method of shaft member of rolling bearing device for wheel. It is a manufacturing method of the shaft member of the rolling bearing device for wheels according to claim 4,
In the first cold forging step, instead of using the fourth intermediate mold and the fourth other mold, the fourth intermediate mold and the fourth other mold are integrally formed. By performing side extrusion using the fourth integrated die, the outer peripheral surface of the fitting shaft portion and the final one side flange surface and the final other side flange surface from the shaft-shaped material. Forming a primary cold forged product in which the one side intermediate diameter inclined flange surface and the other side intermediate diameter inclined flange surface are inclined with a small diameter.
Alternatively, in the second cold forging step, instead of using the fifth intermediate mold and the fifth other mold, the fifth intermediate mold and the fifth other mold are integrally formed. By performing a side extrusion process using the formed fifth integrated die, the outer peripheral surface of the fitting shaft portion, the final one-side flange surface, and the final other side from the first cold forged product Forming a secondary cold forged product in which an inclined flange surface on one side and an inclined flange surface on the other side inclined with respect to the side flange surface are formed;
Alternatively, in the third cold forging step, instead of using the sixth intermediate mold and the sixth other mold, the sixth intermediate mold and the sixth other mold are integrally formed. By performing forward extrusion using the formed sixth integrated mold, the concave portion of the fitting shaft portion, the shaft portion, the final one-side flange surface, and the final shape are obtained from the secondary cold forging product. Forming a shaft member of the rolling bearing device for a wheel which is a tertiary cold forging product in which the other side flange surface is formed;
Manufacturing method of shaft member of rolling bearing device for wheel. It is a manufacturing method of the shaft member of the rolling bearing device for wheels given in any 1 paragraph of Claims 1-5,
Before the first cold forging step, at least annealing treatment and coating treatment are performed on the shaft-shaped material in the first annealing / coating step,
After performing the first cold forging process, before the second cold forging process, at least the annealing process and the coating process are performed again on the shaft-shaped material in the second annealing / coating process. ,
Manufacturing method of shaft member of rolling bearing device for wheel. It is a shaft member of the rolling bearing device for wheels manufactured by the manufacturing method of the shaft member of the rolling bearing device for wheels according to any one of claims 1 to 6,
From the cylindrical shaft-shaped material having an outer diameter corresponding to the outer diameter of the fitting shaft portion when forming the shaft member of the wheel rolling bearing device in the first to third cold forging processes. Manufactured and having the disk-like flange portion,
A shaft member of a rolling bearing device for wheels.

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