JPS5927668B2 - Forging method for outer ring of tri-pot type constant velocity joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for forging an outer ring of a tripot type constant velocity joint.

The outer ring of a tri-pot type constant velocity joint is typically
As shown in the mouth, it is cup-shaped with three grooves a inside.
It has the following.

To manufacture such a constant velocity joint outer ring, 1000 to 120
The material was hot-forged at 0°C and then milled to achieve internal accuracy, or cold sizing was used to achieve internal accuracy.

However, the combination of hot forging and milling has problems such as a decrease in yield due to cutting and an increase in weight due to an increase in outer diameter.

In addition, in the combination of hot forging and sizing, the clearance between the concave die and the rough-ground forged product during sizing and the ironing allowance change over time due to wear of the convex and concave dies used in hot forging. It was necessary to divide it by loft and change the dimensions of the finished concave mold for each loft.

The present invention has been made to solve the problems of the above-mentioned conventional methods, and in particular improves the shortcomings of the combination method of hot forging and sizing. Using a concave die, rough forging is performed in a temperature range of 600 to 800°C, the concave die is left as is, only the convex die is replaced for finishing, and the inner surface of the rough forged product is sized using the convex die at room temperature. This is a method for forging the outer ring of a tri-pot type constant velocity joint, which is characterized by high precision machining.

The present invention will be described in detail below with reference to the drawings. In FIG. 2, a raw material is put into a concave mold 1 and is forged using a first convex mold 2 to form a rough forged product 3.

The temperature range at this time is 600 to 800°C.

Such a temperature range allows backward extrusion of high carbon steels or difficult-to-form materials due to reduced deformation resistance.

In addition, by using induction heating for heating and performing surface treatment on the surface of the material, it is possible to prevent scale from forming on the surface of the material and further prevent decarburization of the material.

If rough ground forging is performed under such conditions, wear of the concave and convex dies will be reduced.

Therefore, a rough forged product having uniform dimensions over time can be obtained.

This rough forged product undergoes uniform thermal contraction when it returns to room temperature.

After annealing and surface treatment, as shown in FIG. 3, the concave die 1 used for rough forging is used as is, and the rough forging is placed therein.

Then, the above heat shrinkage amount directly becomes the clearance C for cold finish sizing.

In this state, sizing is performed by ironing using the second convex die 4, and the inner surface is precisely finished.

FIG. 4 shows the state at the end of the sizing process, and 5 is the sized product.

The present invention is as described above, and the rough ground forging is 600 to 800.
Because the process was carried out at 0°C, there were few dimensional changes in the convex and concave shapes, and there was no dimensional variation over time in the rough forged product.

Therefore, there is no variation in clearance and ironing allowance during sizing, there is no need to change the concave mold over time as in the past, and the mold cost can be greatly reduced by using the concave mold during forging as it is for finishing sizing. can be compressed into

In addition, the yield is improved compared to conventional milling processing, and at the same time, the outer diameter can be reduced and the weight can be reduced.

[Brief explanation of the drawing]

Fig. 1A is a partial cross-sectional view of an example of the outer ring of a conventional tri-pot type constant velocity joint; FIG. 3 is a cross-sectional view at the start of the sizing process, and FIG. 4 is a cross-sectional view at the end of the sizing process. a... Concave groove, C... Clearance, 1
...concave, 2...first convex, 3...
...Rough ground forging, 4...Second convex mold, 5...
···product.

Claims (1)

[Claims] 1 Heat the material to 600-800℃ using convex and concave shapes.
The rough ground forging is carried out in a temperature range of 100 to 100 m, the concave die is left as is, and only the convex die is replaced for finishing, and the inner surface of the rough ground forged product is sized with the convex die at room temperature to achieve high precision processing. Features a forging method for the outer ring of a tri-pot type constant velocity joint.