JPS6234448B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a serration processing method using a serration processing punch provided with a punching guide portion at its tip.

It has been a conventional process to first drill a pilot hole in the workpiece by cold forging or other means, and then serrate the pilot hole by punching with a punch that has a serration section. It's a method. In this case, as shown in Fig. 1a, the burr 3 generated during forging remains on the edge of the prepared hole 2 on the workpiece 1, so first, this burr 3 is completely removed using a punch. The prepared hole 2 is completed as shown in Fig. 1b, and then the prepared hole 2 is serrated using a serration punch to form a predetermined serration 4 as shown in Fig. 1c. This process requires two steps: deburring and serration, which has the problem of requiring a large number of processing steps and lowering productivity.

The present invention has focused on this point, and has been made with the purpose of providing a serration processing method that can perform deburring and serration in one process and improve productivity. A punching guide part is provided at the tip with a cross-sectional shape that matches the cross-sectional shape of the pilot hole and has a total length larger than the total length of the pilot hole, and when this punch is inserted into the pilot hole, the punching guide part allows the punching guide part to punch out the pilot hole. It is characterized in that, while punching out the burrs present at the edges, etc., a punch is further inserted using the punching guide part as a guide, and serration processing by the serration processing part of the punch is performed continuously after the burring. Here, since the entire length of the punching guide part is longer than the pilot hole, the serration process is started while being guided by the pilot hole after the deburring process is completed, and is not affected by the impact during the punching process at all.

As described above, according to the present invention, two types of processing, deburring and serration, can be performed simultaneously by one punching process using one punch, which improves productivity and reduces the need for additional tools such as tool management. This makes it possible to simplify the work.

Next, the present invention will be specifically explained with reference to illustrated embodiments.

FIG. 2 shows an example of the punch 5 used in the present invention, where 6 is a serration processing part and 7 is a punching guide part. The punching guide part 7 is integrally formed at the tip of the well-known serration processing part 6 which has a tooth profile according to the shape of the serration to be processed, and its cross-sectional shape is similar to the pilot hole 2 of the workpiece 1.
It has a shape that can be fitted with a predetermined clearance to There is.

Fig. 3a shows the situation of punching, and Fig. 3b shows the situation of serration processing. First, the workpiece 1, which has been drilled with a prepared hole, is fed to the die 8, which is set to a predetermined clearance. and set it.
Push down the punch 5 and insert the punching guide part 7 into the prepared hole 2.
insert it into the hole and punch out burr 3. At the moment when this punching is completed, the lower end of the serration processing part 6 has not yet reached the upper end of the pilot hole 2, as shown in FIG. 3a. Next, the punch 5 is further pushed down while guiding the punching guide part 7 through the prepared hole 2, and the serration processing part 6 is inserted into the portion of the prepared hole 2 to perform serration processing, as shown in FIG. 3B. Needless to say, the stroke of the punch 5 is selected to a size that allows the serration processing section 6 to complete the processing. In this way, the deburring process and the serration process on the workpiece 1 are performed in one process by punching with one stroke of the punch 5, and each is performed independently with a slight time lag, as shown in Figure 1b. The deburring process to obtain the product can be omitted.

In addition, since the punching guide part 7 is inserted into the pilot hole 2, the lubricant, such as paste oil, applied to the inner surface of the workpiece 1 before machining becomes difficult to escape, and is formed at the upper end of the pilot hole 2. Space 2a (see Figure 4)
This creates a lubricant encapsulation effect in which the lubricant is kept in a sealed state, which eliminates the seizure phenomenon during machining, making machining easier and improving tool life.

As described above, according to the present invention, deburring and serration processing can be performed in one process, improving productivity, simplifying tool management, and extending tool life. This has the effect of improving performance.

[Brief explanation of the drawing]

Figures 1 a to c are sectional views of the workpiece at each processing stage, Figure 2 is a side view of essential parts of a punch used in an embodiment of the present invention, and Figures 3 a and b are processed in the embodiment, respectively. A sectional view showing the situation, and FIG. 4 is an enlarged sectional view of the main part during processing same as above. 1... Workpiece, 2... Prepared hole, 3... Burr, 4
... Serration, 5 ... Punch, 6 ... Serration processing section, 7 ... Punching guide section, 8 ... Die.

Claims (1)

[Scope of Claims] 1. A processing method in which a workpiece that has been subjected to pilot hole processing by means such as cold forging is set in a die, and serration processing is performed on the pilot hole portion using a serration punch. , using a serration punch having a punching guide portion at the tip having a cross-sectional shape that matches the cross-sectional shape of the pilot hole and having a total length larger than the total length of the pilot hole, and inserting this punch into the pilot hole. The punching guide section punches out the burr existing at the end of the pilot hole, and a punch is further inserted using the punching guide section as a guide, and the serration processing section of the punch continues the serration processing after punching out the burr. A serration processing method characterized in that the serration processing is performed by