JPS61137643A - Production of outer race of revro joint - Google Patents

Abstract

PURPOSE:To obtain the titled outer race elevating a groove accuracy by performing a heat treatment after forming a cross groove in the reverse direction to the deflection direction at the corresponding place by the prefound displacement amount from the normal dimension due to the heat treatment of the outer race. CONSTITUTION:A cross groove is formed on the inner face of the outer race 1 of the divided type REVRO joint (cross groove unversal joint) of S55 quality for instance by bending the prescribed quantity toward the outer side of the radial direction against the axial direction of the inner face by a cold forging method with using a forming die 2 and mandrel 3. In case of forming this cross groove the blank outer race material is led from the upper part with the state of fitting in the fitting groove of the mandrel 3 by moving the mandrel 3 in advance to the arrow marked direction A in the figure and simultaneously by moving the forming die 2 in the direction C. The cross groove is then formed by shifting said rough formed material in the direction D with the outer die. The B.D.D. part of the cross groove part is restored to nearly normal dimension by high frequency hardening and cooling after drawing out the outer race 1 from the knockout of the lower part to the upper part of the die 2 after shrinking the die 2 in the direction D by moving the mandrel 3 in the direction B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing an outer race of a Rebro joint.

[Conventional technology]

The Rebro joint, which is a telescopic constant velocity joint used in the automobile industry, is composed of a plurality of poles, usually six, a cage that holds the poles, an outer race, and an inner race. The ball grooves on the inner race and the inner race are arranged in a V-shape, that is, they are inclined symmetrically to each other by equal angles with respect to the rotation axis.

This ball groove rubs violently with the pole, so it needs to have sufficient abrasion resistance.The outer race and inner race are formed by machining and preservative processing, and then the inner surface, which includes a part of the groove where the pole comes into contact, is conventionally formed. The entire structure was hardened by means such as carburizing or high-frequency heating.

[Problem that the invention seeks to solve]

Therefore, the outer race is usually manufactured using a steel material. The structure of the steel material used in this case is a mixed structure of ferrite and pearlite, but when carburized or hardened by high-frequency heating, the structure changes to martensite, and at this time the volume expands. This volumetric expansion is caused by the quenched part, i.e. 7
, occurs only on the inner surface of the outer race, so the inner surface deforms and protrudes, causing the inner diameter and grooves B, B, and D (between BLI l diameters) at both axial ends of the outer race to be larger than those at the center of the shaft. becomes.

Particularly when the pole l+1 is of the above-mentioned V shape, deformation due to distortion becomes complicated, so it is very difficult to correct the dimensions to the regular size by cutting, etc. after quenching.

For this reason, in the conventional outer race for Rebro joints, the central part of the groove was raised compared to both ends, so the deviation from a true cylinder (the height of the raised part), that is, the cylindricity was 0. lO~0
．． It is approximately 15m5, and the groove accuracy is reduced, and the vibration caused by this quenching distortion.

Noise and reduced durability were problems.

The present invention is intended to solve the above-mentioned problems in the prior art, and its purpose is to provide a simple manufacturing method for obtaining a highly durable Rebro joint with improved groove precision, less vibration and noise. Our goal is to provide the following.

[Means to solve the problem]

That is, in the method for manufacturing the outer race of the 70-inch outer race of the present invention, when performing heat treatment after forming cross grooves in the outer race of the Rebro joint, the amount of displacement from the normal dimension due to heat treatment distortion is determined in advance, and the heat treatment distortion is generated. The cross groove is formed by deforming the portion by the above displacement amount in a direction opposite to the strain direction, and then heat treatment is performed.

Types of outer races to which the method of the present invention can be used include, for example, split types that are separate from the shaft, and shaft-integrated types that are integrated with the shaft. Furthermore, various materials can be used for the outer race, such as carbon steel for mechanical structures, chromium molybdenum steel, etc.

To determine in advance the amount of displacement of the outer lace from the normal dimensions due to heat treatment distortion, for example, the average value of the amount of displacement of multiple prototypes manufactured without using the method of the present invention may be determined, or the material of the outer lace, It is best to calculate the displacement using a computer, etc., using the size, shape, and various physical properties of the material under manufacturing conditions. It is convenient to write it down or store it in a computer's memory.

Next, when forming cross grooves on the outer race using means such as cold forging or machining, 1-. Cross grooves are formed by deforming each portion in a direction opposite to the strain direction by the amount of displacement determined above for the portion where strain occurs due to the heat treatment performed. In this case, if the machine tool is controlled by a computer that stores the above-mentioned displacement amount, the work efficiency is improved, and it is of course possible to control the machine tool manually.

Next, the outer race is heat treated under predetermined conditions. As the heat treatment method, methods normally used for mechanical work such as induction hardening and carburizing hardening can be used, and the method selected depending on the properties such as the material and size of the outer race can be used. good.

(Examples) The present invention will be explained in more detail in the following examples.It should be noted that the present invention is not limited to the following examples.

Example 1: Outer diameter 112mmφ, inner diameter 75IllIΦ, length 38+a
+a, the inner surface of the outer race l of the split-type Rebro joint made of material S and 55C is made by cold forging using the forming die 2 and mandrel 3 shown in Fig. A cross groove was formed by curving a predetermined amount toward . The mold 2 was of a split type in consideration of the removal of the outer race l after the grooves were formed. That is, when forming cross grooves, the mandrel 3 is moved in advance in the direction of arrow A in the figure, and at the same time the mold 2 is moved in the direction of C to fit into the fitting groove of the mandrel 3. condition)
A cross groove is formed by gathering the outer race rough profile in the D direction using a zero-order outer die (not shown) that is inserted from above. Next, move the mandrel 3 in the direction B, and move the mold 2 in the direction D.
After being shrunk in this direction, the outer lace 1 is pulled out above the mold 2 by a downward knockout (not shown). When the outer race l with the cross grooves formed thereon is induction hardened under predetermined conditions and then cooled, the curvature of the axial center of the cross grooves of the outer race l is corrected due to heat treatment distortion, and the cross grooves B, B, and D are An outer lace l having almost regular dimensions was obtained.

FIG. 2 shows changes in the groove portions B, B, and D before and after induction hardening, corresponding to each portion of the gross groove of the outer race 1. As is clear from the figure, B after induction hardening,
It can be seen that each part of B and D has almost normal dimensions.

Example 2: Outer diameter of outer lace part: 86 layers φ, inner diameter 75■φ,
The same as in Example 1 except that the groove effective length is 38 tw, the shaft-integrated outer race 4 made of material 555C, and a split-type mold whose bottom side in the figure is widened in place of the mold 2 in FIG. 1. An outer lace 4 was obtained in which a cross) 4 was formed.

FIG. 3 shows changes in the grooves B, B, and D of the outer race 4 before and after induction hardening.

In the case of the outer race cow before induction hardening, the cylindrical part extends outward at the bottom in the figure, but after induction hardening, Example 1
The dimensions are almost standard.

Comparative Example 1: A cross groove was formed in the outer race 5 shown in FIG. 4 in the same manner as in Example 1, but without curving the axially central portion toward the outside in the radial direction. The axial center portion protrudes radially inward to form grooves B, B,
D was wider than the standard size.

Comparative Example 2: A cross groove was formed in the outer race 6 shown in Fig. 6 in the same manner as in Example 2, except that the lower side of the cylindrical part in the figure was not expanded outward. The lower side of the groove was bent inward in the radial direction, and the grooves B, B, and D were significantly different from the standard dimensions.

1 Durability comparison test: A Rebro joint using an outer lace manufactured by the method of the present invention in an example and a Rebro joint using an outer lace manufactured by a conventional method in a comparative example were attached to a testing machine and tested under the same conditions. When we compared the durability (durability time), we found that the products using the uninvented method were about 10 to 30% more durable than the products using the conventional method, and the vibration and noise during testing were also improved. It has decreased significantly.

〔Effect of the invention〕

As shown in h4, the method for manufacturing the outer race of the Rebro joint of the present invention involves determining in advance the amount of displacement from the normal dimensions due to heat treatment distortion of the outer race, and deforming the corresponding portion by the amount of displacement in the opposite direction to the strain direction. B after heat treatment
,B.

D becomes almost equal to the regular dimension, improving groove accuracy, eliminating uneven contact between the cross groove and the pole when configuring the Rebro joint, and averaging the contact surface pressure of the poles. Durability has been improved compared to Rebro joints that use manufactured outer laces. or,
Since the method of the present invention deforms the outer race at the same time as forming the cross grooves, it is simple and applicable to outer races of various shapes. Since the amount of deformation and the deformed shape can be easily adjusted, Rebro joints with various properties and excellent characteristics can be easily manufactured.

It has various effects such as increasing the reliability and commercial value of products such as vehicles that use Revlogi 1 India.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention. FIG. 2 shows the groove portions B of each cross groove of the outer race manufactured by the method shown in FIG. 1 before and after induction hardening,
A diagram showing changes in B and D, FIG. 3 is a diagram showing the same relationship as FIG. 2 of another embodiment of the present invention, and FIGS. 4 and 5 are outer laces manufactured using a conventional method. Figures 6 and 7 are partial sectional views showing the shapes before and after heat treatment of other examples of outer lace manufactured using the conventional method. It is. In the diagram, 1.4, 5.5', 6.6'... Outer lace 2.
...Molding mold 3...Ma/Drel patent Offender Toyota Motor Corporation Fig. 1 1.4, 5.5', 6.6'...Outer race No. 2
Figure 3 Figure 4 Figure 5 Figure 6 Figure 7'

Claims (1)

[Claims] When performing heat treatment after forming cross grooves on the outer race of the Rebro joint, the amount of displacement from the normal dimensions due to heat treatment distortion is determined in advance, and the portion where the heat treatment distortion occurs is deformed by the above displacement amount in the opposite direction to the distortion direction. A method for manufacturing an outer lace for a Rebro joint, which comprises forming cross grooves and then heat-treating.