JP2001347803A - Hub unit for vehicle and manufacturing method for constant velocity joint for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce working costs by unnecessitating turning for an outer ring inside surface after molding a constant velocity joint in a hub unit. SOLUTION: In the hub unit 10 for vehicle including a hub wheel 11 mounted with a wheel, a double-row rolling bearing 13 mounted externally on the hub wheel 11 and rotatably supporting the hub wheel 11 on a main body 11a and a constant velocity joint 12 coupled integrally with the hub wheel 11 and tiltably connecting a power transmission shaft 30 with the hub wheel 11, the outer ring 25 of the constant velocity joint 12 has a bowl-like cylinder part 25a to be a raceway of a plurality of ball groups for a tilting operation and a cylinder shaft part 25b connected integrally with a small diameter part of the cylinder part 25a and mounted internally on the hub wheel 11, in a state of the part 25b and the hub wheel 11 integrated in at least a rotating direction and the outer ring 25 is manufactured by performing cold forging for cylindrical steel products.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle hub unit (hereinafter simply referred to as a hub unit) to which a disk rotor and wheels of a disk brake device are mounted, and a method of manufacturing a constant velocity joint thereof.

[0002]

2. Description of the Related Art There has been proposed a form in which a Zeppa type constant velocity joint is incorporated into a hub unit to integrally connect a power transmission shaft. In this case, for the outer ring of the constant velocity joint, a bowl-shaped cylindrical portion that serves as a trajectory of a ball group for tilting guidance, and a shaft for coupling to the hub wheel of the hub unit at a small diameter portion of the bowl-shaped cylindrical portion. And has a structure.

[0003] In this outer ring, the shaft portion is made hollow for weight reduction, and the shaft portion and the bowl-shaped tube portion are provided with a partition wall for ensuring the sealing performance inside the bowl-shaped tube portion, and are communicated with each other. It has a structure that does not allow it. The outer ring of such a constant velocity joint is conventionally manufactured by hot forging because its shape is complicated.

[0004]

In such a hub unit, the outer race of the constant velocity joint is manufactured by hot forging as described above. In this hot forging, the outer race of the constant velocity joint is formed. Turning, rough polishing, and finishing polishing are performed on the inner surface, which requires a lot of time and effort, and the processing cost is high.

In addition, in the hub unit having the partition wall, it is preferable to make the partition wall thin in order to easily radiate the heat generated by the constant velocity joint to the cylindrical shaft portion. Therefore, even if the thickness of the partition wall is reduced, there is a limit, and a structure with a higher heat radiation effect is required.

[0006] Therefore, the present invention has a common problem to solve the problem of turning the inner surface of the outer ring of the hub unit after forming the constant velocity joint, thereby reducing the processing cost.

Another object of the present invention is to improve the structure in which the heat radiation effect with respect to the heat generated in the constant velocity joint is improved.

[0008]

(1) A hub unit according to the present invention comprises: a hub wheel to which a wheel is attached; a double row rolling bearing which is mounted on the hub wheel and rotatably supports the hub wheel with respect to a main body; And a hub unit including a constant velocity joint integrally coupled to the hub wheel and tiltably connecting the power transmission shaft to the hub wheel, wherein the outer ring of the constant velocity joint is a plurality of ball groups for tilting operation. A bowl-shaped cylindrical portion serving as a raceway, and a cylindrical shaft portion integrally connected to the small-diameter portion of the cylindrical portion and housed in the hub wheel so as to be integrated at least in the direction of rotation. It is manufactured by cold forging a steel shape.

According to the hub unit of the present invention, the outer race of the constant velocity joint is formed by cold forging a tubular steel material. Eliminating the work of performing the processing, the processing cost is reduced.

[0010] In the case of the hub unit, a lid for separating the inside of the bowl-shaped tube portion and the inside of the cylindrical shaft portion of the outer race of the constant velocity joint is provided to enhance the heat radiation effect inside the bowl-shaped tube portion. When the thickness of the lid is reduced in the axial direction, or when the lid is made of a material having excellent thermal conductivity, the heat generated inside the bowl-shaped cylindrical portion of the constant velocity joint is reduced to the cylindrical shaft side. It is preferable because heat can be easily dissipated.

In the case of the hub unit, if the outer peripheral surface of the outer race of the constant velocity joint forms the raceway of the other inner race of the double-row rolling bearing, the outer race is cold forged. On the other hand, turning on the raceway surface of the inner ring becomes unnecessary, and the machining cost can be reduced also in this regard.

(2) A method of manufacturing a constant velocity joint in a hub unit according to the present invention includes a hub wheel to which a wheel is attached, and a double row rolling bearing which is mounted on the hub wheel and rotatably supports the hub wheel with respect to the main body. A method for manufacturing the constant velocity joint in a vehicle hub unit including a constant velocity joint integrally coupled to a hub wheel and tiltably coupling a power transmission shaft to the hub wheel, wherein the constant velocity joint is A bowl-shaped tube portion that serves as a trajectory of a plurality of ball groups for tilting operation, and a cylindrical shaft portion integrally connected to a small-diameter portion of the tube portion and internally housed in the hub wheel at least in a rotational direction. An outer mold having an outer ring including an outer die having an uneven surface corresponding to the outer diameter surface shape of the outer ring on an inner peripheral wall surface and an inner die surface shape of the outer ring on an outer peripheral wall surface. And a tubular steel is plastically deformed by cold forging with an inner mold having a response was irregular surface to fabricate the outer race from the cylindrical steel.

According to the manufacturing method of the present invention, the outer ring of the constant velocity joint is manufactured by cold forging a tubular steel material between the outer die and the inner die. Turning to the inner surface of the outer ring becomes unnecessary, and the machining cost can be reduced.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on embodiments shown in the drawings.

FIG. 1 and FIG. 2 show an embodiment of the present invention. FIG. 1 is a longitudinal side view of the hub unit, and FIG.
FIG. 4 is a schematic view showing a usage mode of a hub unit.

The illustrated hub unit 10 includes a hub wheel 11, a constant velocity joint 12, and a double-row rolling bearing 13. A double-row rolling bearing 13 is provided around the hub wheel 11 on the outer periphery of the hub wheel 11. Constant velocity joint 1 on inner circumference
2 is incorporated.

The hub wheel 11 has a cylindrical main body 11a.
And a radially outward flange 11b at the axially outer end. At several places around the circumference of the flange 11a,
A bolt insertion hole 15 is formed, and a bolt 16 is inserted into each bolt insertion hole 15 in a penetrating state. The disc rotor 17 and the wheel (not shown) of the disc brake device are arranged along one surface of the flange 14 via the bolt 16.
Is attached. 18 is a brake pad.

The double row rolling bearing 13 includes a single outer ring 19 having two rows of raceways, a plurality of balls 20 as rolling elements arranged in two rows, two crown retainers 21, and a hub wheel 1.
The outer peripheral surface of the main body 11a of one of the two is an inner ring, the constant velocity joint 1
The outer ring 25 has a configuration in which the outer peripheral surface of the outer ring 25 is used as the other inner ring, and the inner ring is pressed from the caulking portion 22 to apply a required preload (compressive stress) and prevent the inner ring from coming off.

A flange 23 is formed on an outer ring 19 of the double row rolling bearing 13, and the flange 23 is bolted to a vehicle body 24.

The constant velocity joint 12 is generally a CVJ
(Constant Velocity Joint), which has an outer ring 25, an inner ring 27, a plurality of ball groups 28, a retainer 29, and the like, and is integrally connected to the hub wheel 11 to be connected to the hub wheel. A drive shaft 30 serving as a power transmission shaft is connected to the motor 11 in a tiltable manner.

The outer race 25 of the constant velocity joint 12 has a bowl-shaped cylindrical portion 2 which is a trajectory of the plurality of balls 28 for the tilting operation.
5a and a cylindrical shaft portion 25b integrally connected to the small-diameter portion of the bowl-shaped tubular portion 25a and integrated with the hub wheel 11 in a rotational direction.

In the outer ring 25 of the constant velocity joint 12, a receiving surface 25a for receiving the double row rolling bearing 13 from the axial direction is provided on the inner end side in the axial direction on the outer periphery of the bowl-shaped cylindrical portion 25a.

The cylindrical shaft portion 25b of the outer race 25 of the constant velocity joint 12 is spline-fitted to the inner peripheral surface of the hub wheel 11, and its axially outer end portion 22a is The caulking portion 22 is bent radially outward with respect to the outer end face in the direction and is caulked, thereby being integrated with the hub wheel 11. The swaged portion 22 allows the double row rolling bearing 13
, And a preload is applied.

One end of a shaft 30 is spline-fitted to the inner ring 27 of the constant velocity joint 12 and is fixed by a retaining ring 31 or the like. Thereby, the shaft 3
The rotation power of 0 is transmitted to a wheel (not shown) attached to the hub wheel 11 via the constant velocity joint 12. The illustration of the boot of the constant velocity joint 12 is omitted.

The constant velocity joint 12 is usually
0 and a constant velocity joint 32 attached to the other end of the shaft 30, a shaft assembly 33 is formed. In the hub unit 10 of this embodiment, since the constant velocity joint 12 is incorporated, the shaft assembly 33 is provided. Product. 35 is a differential device.

The hub unit 10 of this embodiment
The lid 34 is provided inside the constant velocity joint 12 to ensure the hermeticity such as to prevent entry of foreign matters such as rainwater and dust, and to prevent oil in the constant velocity joint 12 from leaking outside. Have been. The thickness of the lid 34 is a separate structure from the constant velocity joint 12, so that the lid 34 can have a thin structure in order to enhance the effect of radiating heat generated in the constant velocity joint 12.

In this case, when the lid 34 is made of a material having excellent thermal conductivity, the effect of smoothly radiating the heat generated in the constant velocity joint 12 from the lid 34 to the inside of the cylindrical shaft portion 25b is enhanced. It is preferable to improve the life of the constant velocity joint 12 by using the outer ring 25 of the constant velocity joint 12.
If it is made of a material having better thermal conductivity, the rate of the generated heat is higher than that of the outer ring 25, so that the rate of heat conduction to the lid 34 is higher. As a result, the life of the constant velocity joint 12 can be improved more. It is preferable because it can be achieved. As this material, for example, there are alloys such as aluminum, copper, and zinc. Further, the lid 34 may be provided with a radiation fin on the side facing the inside of the cylindrical shaft portion to increase the radiation area and enhance the radiation effect.

Next, the constant velocity joint 12, especially its outer ring 2
5 will be described with reference to FIGS.

This manufacturing method is essentially the same as that of the outer race 25
Is manufactured by cold forging.
An outer mold 40 and an inner mold 50 as shown by are prepared.

The outer die 40 is an outer ring 2 of the constant velocity joint 12.
5 has an inner peripheral wall surface 40a having an uneven surface corresponding to the outer diameter surface shape of the bowl-shaped cylindrical portion 25a, and an inner peripheral wall surface 40b having an uneven surface corresponding to the outer diameter surface shape of the cylindrical shaft portion 25b. , Are fixed to appropriate portions.

The inner die 50 is an outer ring 2 of the constant velocity joint 12.
5 is provided with an outer peripheral wall surface 50a having an uneven surface corresponding to the inner diameter surface shape of the bowl-shaped cylindrical portion 25a, and an outer peripheral wall surface 50b having an uneven surface corresponding to the inner diameter surface shape of the cylindrical shaft portion 25b. The descent control is performed.

Then, as shown in FIG. 3, the tubular steel material 60 is disposed inside the outer die 40, and the inner die 50 is lowered. Here, the outer diameter of the tubular steel material 60 is slightly smaller than the inner diameter of the inner peripheral wall surface 40b of the outer mold 40, and the inner diameter is substantially equal to or slightly smaller than the outer diameter of the outer peripheral wall surface 50b of the inner mold 50. are doing.

The steel material is formed into a cylindrical shape, for example, in order to improve the accuracy of the forging process.
Is not limited as long as it is cylindrical. The steel material 60 is, for example, carbon steel or alloy steel.

The tubular steel material 60 is provided with the two molds 40,
As shown in FIG. 4, the plastic deformation occurs in accordance with the shape of the wall 60.

The plastically deformed tubular steel material 60 is shown in FIG.
The outer ring 25 of the constant velocity joint 12 is manufactured by taking it out of both the molds 40 and 60 as shown by.

In the case of such manufacturing, since the outer ring 25 of the constant velocity joint 12 has a low forging temperature, the cylindrical steel material 60 does not flow and the crystal grains do not become coarse. There is no need to perform turning after forging.

In this case, forging is usually performed at room temperature, but includes processing performed at a temperature equal to or lower than warm forging.

However, in the case of cold forging, strain hardening tends to increase when the cylindrical steel material 60 is processed at a high speed. Therefore, it is preferable to suppress the strain hardening by lowering the inner mold 50 at a low speed. .

According to the above embodiment, since the outer race 25 of the constant velocity joint 12 is manufactured by cold forging, the turning operation is performed on the inner surface of the outer race 25 of the constant velocity joint 12 after the forging. It is unnecessary and the processing cost is reduced.

The present invention is not limited to the above embodiment, and various modifications and applications are possible.

(1) In the above embodiment, the raceway surface of the other inner ring of the double row rolling bearing 13 is constituted by the outer peripheral surface of the bowl-shaped cylindrical portion 25a of the outer ring 25 of the constant velocity joint 12.
As shown in FIG. 6, the other inner ring is a bowl-shaped cylindrical portion 2 of an outer ring 25.
The inner ring 70 may have a structure separate from that of the inner ring 5a, and the inner ring 70 may be received by the outer peripheral surface of the bowl-shaped tubular portion 25a.

(2) In the above embodiment, the raceway surfaces of the one inner ring and the other inner ring of the double row rolling bearing 13 correspond to the main body 11a of the hub wheel 11 and the bowl-shaped cylindrical portion 25a of the outer ring 25 of the constant velocity joint 12, respectively. As shown in FIG. 7, each of the one and the other inner rings is constituted by an inner ring 71, 70 having a separate structure, and the inner rings 71, 70 are formed by a main body 11a of the hub wheel 11. And the outer peripheral surface of the bowl-shaped cylindrical portion 25a of the outer ring 25 of the constant velocity joint 12 may receive the outer ring 25.

[0043]

As described above, in the case of the present invention, the outer race of the constant velocity joint is integrally connected to the bowl-shaped cylindrical portion which becomes the trajectory of the plurality of balls for tilting operation and the small diameter portion of the cylindrical portion. The hub wheel has at least a cylindrical shaft part that is housed integrally with the hub in a rotational direction, and since this outer ring is manufactured by cold forging a cylindrical steel material, the constant velocity joint is formed after the forging. This eliminates the need to perform a turning operation on the inner surface of the outer ring, thereby reducing the machining cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a hub unit according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a use mode of the hub unit of FIG. 1;

FIG. 3 is a first process diagram for explaining the manufacture of the outer race of the constant velocity joint.

FIG. 4 is a second process diagram for explaining the manufacture of the outer race of the constant velocity joint.

FIG. 5 is a third process diagram for explaining the manufacture of the outer race of the constant velocity joint.

FIG. 6 is a longitudinal sectional side view of a hub unit according to another embodiment of the present invention.

FIG. 7 is a longitudinal sectional side view of a hub unit according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hub unit 11 Hub wheel 11a Hub wheel main body 12 Constant velocity joint 13 Double row rolling bearing 25 Outer ring of constant velocity joint 25a Bowl-shaped cylindrical part of outer ring of constant velocity joint 25b Cylindrical shaft part of outer ring of constant velocity joint 40 Outer die 50 Inner die 60 tubular steel

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) F16D 3/224 F16D 3/224 A (72) Inventor Satoshi Araki 3-5-8 Minamisenba, Chuo-ku, Osaka-shi F-term (reference) in Koyo Seiko Co., Ltd. 3J101 AA02 AA32 AA43 AA54 AA62 AA72 AA83 BA53 DA09 EA02 FA44 GA02 GA13 4E087 CB03 HA22

Claims (5)

[Claims] 1. A hub wheel to which a wheel is attached, a double row rolling bearing which is provided on the hub wheel and rotatably supports the hub wheel with respect to a main body, and which is integrally connected to the hub wheel and is attached to the hub wheel. A vehicular hub unit including a constant velocity joint that tiltably connects a power transmission shaft, wherein an outer ring of the constant velocity joint forms a track of a plurality of balls for tilting operation, and A cylindrical shaft portion integrally connected to the small-diameter portion of the hub wheel and housed in the hub wheel so as to be integrated with at least the rotation direction. The outer ring is manufactured by cold forging a cylindrical steel material. And a hub unit for a vehicle. 2. The vehicle hub unit according to claim 1, further comprising a lid for separating the inside of the bowl-shaped tube portion and the inside of the cylindrical shaft portion of the outer ring of the constant velocity joint, and dissipating heat inside the bowl-shaped tube portion. The vehicle hub unit according to claim 1, wherein the thickness of the lid is reduced in the axial direction in order to increase the thickness. 3. A hub unit for a vehicle according to claim 1, further comprising a lid for separating the inside of the bowl-shaped tube portion and the inside of the cylindrical shaft portion of the outer ring of the constant velocity joint, and dissipating heat inside the bowl-shaped tube portion. A hub unit for a vehicle, wherein the lid is made of a material having excellent thermal conductivity in order to enhance the effect. 4. The hub unit for a vehicle according to claim 1, wherein an outer peripheral surface of an outer ring of the constant velocity joint forms a track of the other inner ring of the double row rolling bearing. . 5. A hub wheel to which a wheel is attached, a double row rolling bearing which is mounted on the hub wheel and rotatably supports the hub wheel with respect to the main body, and which is integrally connected to the hub wheel and is attached to the hub wheel. A method of manufacturing the constant velocity joint in a vehicle hub unit including a constant velocity joint that tiltably connects a power transmission shaft, wherein the constant velocity joint is a trajectory of a plurality of ball groups for a tilting operation. An outer ring including a cylindrical portion and a cylindrical shaft portion integrally connected to the small-diameter portion of the cylindrical portion and housed in the hub wheel so as to be integrated at least in the direction of rotation; and The cylindrical shape is formed by cold forging using an outer mold having an uneven surface corresponding to the outer surface shape of the outer ring and an inner mold having an uneven surface corresponding to the inner surface shape of the outer ring on the outer peripheral wall surface. The wood by plastically deforming fabricating the outer ring from the tubular steel, constant velocity joint manufacturing method of a hub unit for a vehicle, characterized in that.