JP3404067B2 - Constant velocity joint and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to heat treatment for forging, rough finishing by machining, and then surface hardening and quenching.
The present invention relates to a constant velocity joint which is treated , finished again, and finally assembled to each other, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, heat treatment such as annealing or normalizing is performed to remove internal stress generated by forging, followed by rough finishing by machining, and then quenching again. Alternatively, heat treatment such as tempering is performed, and finish processing by cutting is performed again, and finally the core and the core insertion member are assembled to each other.

[0003]

However, in the conventional art, it is difficult to match the core and the core insertion member in the constant velocity joint, and if unmatched joints are combined with each other, rattling may occur. There was a high risk that it would be easily scuffed and damaged, and its life would be shortened.

Therefore, an object of the present invention is to obtain a constant velocity joint and a manufacturing method thereof which can easily match the core and the core insertion member, do not cause rattling or excessive galling, and have a long life. It is in.

[0005]

Means for Solving the Problems] To achieve this object, the present invention a constant velocity joint, to the roughing core of the constant velocity joint and the heat treatment, the cutting after the heat treatment
Finishing is not performed , and the heat treatment is performed under the same joint angle, torque, and rotation speed as the usage conditions.
Sliding and rotating the rough-finished core insertion member
Finishing is performed by sliding the inner surface of the core.
In the disassembled set of the core and the core insertion member in which the inner surface of the core has a smooth surface and a residual compressive stress exists, the core and the core insertion member are matched with each other regardless of whether they are the same set during operation. It is characterized by assembling as a finished product by selecting comrades.

Further, in the method for manufacturing a constant velocity joint according to the present invention , a cutting process after heat treatment is performed as the finishing process.
The heat-treated constant velocity joint rough-finished core.
Then , the insertion member is slid and rotated on the rough finishing core at the joint angle, torque and rotation speed under almost the same conditions as the operating condition to bring the surface into a smooth state and a state where compressive residual stress exists on the surface. A dynamic machining step, a step of disassembling a set of constant velocity joints that have undergone sliding processing, and a disassembled core and core insertion member that match each other regardless of whether they are the same group during operation. Is selected and assembled as a finished product.

[0007]

According to the constant velocity joint of the present invention, after the heat treatment of the surface hardening and quenching, only the sliding process is performed, and the two-stage machining process of rough finishing of machining and final finishing of cutting is performed. Rather, the core and the core insertion member that match each other are selected and assembled as a finished product.

[0008]

The preferred embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 shows a BJ constant velocity joint 1 according to the present invention. According to the present invention, the material of SCM420 is used for the housing 2 as the core, and gas carburizing quenching and tempering is performed as the core internal surface hardening and quenching to obtain the following properties.

That is, Effective hardened layer depth 0.8mm Surface hardness Hv650 Surface hardening Hardened layer Metallographic structure Tempered martensite Initial surface residual stress -260 MPa First surface roughness 3.1S

According to the present invention, the core (housing) 2 and the core insertion member 3 to be inserted into this core are assembled as a constant velocity joint 1, and at this time, a lubricant is enclosed. In this state, this constant velocity joint is processed. As the processing conditions, the constant velocity joint 1 of FIG. 1 is operated under the following torque, joint angle, and rotation angle. That is, torque 235 N · m, joint angle 0 to 40 °, rotation speed 1000 rpm

As a result of the processing of this first embodiment, the properties of the inner surface of the core were as follows. Inner core surface hardness Hv725 Inner core surface roughness 0.5S Inner core surface residual stress -530MPA

The constant velocity joint processed in this manner is disassembled and washed, and then the core and the core insertion member which are aligned with each other are selected, and the constant velocity joint is assembled as a product. The service life of the constant velocity joint manufactured in this way was 1.7 times that of the conventional product.

FIG. 2 shows a TJ type constant velocity joint 10 according to the present invention. According to the present invention, the material of SCM48C is used for the housing 20 as the core, and induction hardening and tempering is performed as the core internal surface hardening and quenching to obtain the following properties.

That is, Effective hardened layer depth 1.2mm Surface hardness Hv580 Surface hardening Hardened layer Metallographic structure Tempered martensite Initial surface residual stress-340 MPa First surface roughness 12.5S

According to the present invention, the core (housing) 20 and the core insertion member 30 to be inserted into this core are assembled as a constant velocity joint, and at this time, a lubricant is enclosed. In this state, the constant velocity joint is slid. The constant velocity joint 10 shown in FIG. 2 is operated under the following sliding conditions under the following conditions: torque, joint angle, and rotation angle. That is, torque 235 N · m, joint angle 0 to 20 °, rotation speed 1000 rpm

As a result of the sliding process of the second embodiment, the properties of the inner surface of the core were as follows. Inner core surface hardness Hv650 Inner core surface Asara 2.0S Inner core surface residual stress -570MPA

The sliding constant-moving constant velocity joint is disassembled and washed, and then the core and the core insertion member that match each other are selected, and the constant velocity joint is assembled as a product. The service life of the constant velocity joint manufactured in this way was 1.5 times that of the conventional product.

As the surface hardening and quenching, there are carbon carburizing and quenching methods other than the gas carburizing and quenching and induction hardening as in the above-mentioned embodiment. In the case of the embodiment of FIG.
Distance from surface of material by heat treatment (mm) and surface hardness (Hv)
The relationship is as shown in the graph of FIG. 3 (however, the solid line shows the graph before the sliding process and the dotted line shows the graph after the sliding process). In the case of the embodiment shown in FIG. 2, a similar graph is obtained.

The residual stress on the inner surface of the core of the embodiment of FIGS. 1 and 2 due to machining is as shown in the graph of FIG. 4 (however, the solid line shows the graph before sliding, and the dotted line shows after sliding. Of the graph).

It is also possible to use a constant velocity joint core without cracks or deformation, which has been used in the past, in place of the sliding work as in the embodiment of FIGS. 1 and 2, although similar results can be obtained. It is a range.

[0022]

According to the present invention, since the sliding process is performed and the optimum combination is selected and combined, the clearance of the core of the component to be inserted into the core (housing) can be reduced. As a result, It is possible to prevent backlash and imbalance. This is remarkable in the slide type constant velocity joint.

Furthermore, as a result of the sliding process, the hardness of the inner surface of the core is increased as compared with that before the processing, and the residual stress on the inner surface of the core is also large in the-(minus) side as compared with that before the processing. As a result, the strength can be increased, stress concentration can be prevented during actual operation of the constant velocity joint, durability can be improved, and life can be increased.

Further, according to the present invention, since the constant velocity joint core which has been used but has no cracks or deformations can be recycled, there is an effect that the generation of industrial waste can be reduced. .

[Brief description of drawings]

FIG. 1 is a side view showing a partial cross section of a B / J type constant velocity joint according to a first embodiment of the method of the present invention,

FIG. 2 (a) is a side view showing a partial cross section of a TJ type constant velocity joint according to a second embodiment of the method of the present invention, and FIG.
[Fig. 3] is a side view showing a partial cross section of the core, and (c) is an end view of the core.

3 is a graph showing the relationship between the distance (mm) from the surface of the material and the surface hardness (Hv) by the heat treatment of the example of FIG. 1 and the change after sliding working.

FIG. 4 is a graph of FIG. 4 showing residual stress on the inner surface of the core of the embodiment of FIGS. 1 and 2 due to processing, a solid line shows a graph before sliding, and a dotted line shows a graph after sliding. Show.

[Explanation of symbols]

1 B / J type constant velocity joint 2,20 core (housing) 3,30 core insert 10 T / J type constant velocity joint

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Claims (3)

(57) [Claims] 1. Roughly finishing by forging and machining
It was carried out, then, the heat treatment of surface hardening hardening, finishing
Finishing by cutting after the above heat treatment in a constant velocity joint consisting of a core that is processed and finally assembled together and a core insertion member that is inserted into this core
No processing is performed , and the heat-treated rough-finished core insertion member is slid and rotated with respect to the rough-finished core of the constant velocity joint at the joint angle, torque, and rotation speed under almost the same conditions as the condition of use. Operate and slide the inner surface of the core
Finishing process is carried out by disassembling the set of the core and the core insertion member in a state where there is a smooth surface and compressive residual stress on the core inner surface, and among the disassembled ones,
A constant velocity joint characterized by being assembled as a finished product by selecting those who match each other regardless of whether they are the same set during operation or not. 2. A set of disassembled sets of a core and a core insertion member of a used constant velocity joint, which are matched with each other regardless of whether they are the same set during operation. The constant velocity joint according to Item 1. 3. A constant velocity joint core and a core insertion member to be inserted into this core are respectively forged and machined .
Perform roughing, then these cores and core insert the heat treatment of the surface hardening quenching, perform finishing, in the manufacturing method of a constant velocity joint finally assembling the core and the core insert members together, said As a finishing process, without cutting after heat treatment,
For the rough finish core of the heat treated constant velocity joint
And sliding operation of the rough finish core insertion member by sliding and rotating with the joint angle, torque and rotation speed under almost the same conditions as in use, to make the surface smooth and in which there is compressive residual stress on the surface. Step, step of disassembling a set of constant velocity joints that have been subjected to sliding processing, and selection of disassembled cores and core inserts that match each other regardless of whether they are the same set during operation And a step of assembling as a finished product.