JPH0866732A - Manufacture of bulge nipple - Google Patents

Abstract

PURPOSE: To enable mass production even for a small bulge nipple with high precision in shape. CONSTITUTION: This manufacture consists of a first process for forming a drawn cylindrical body 2 with a bottom, a second process for press-forming the drawn cylindrical body 2 into a bulged cylindrical body 2' and a third process for punching out the bottom of the bulged cylindrical body 2'. The second process is performed by means of a press die which is provided with a lower die 3, upper die 4, first punch 5, second punch 6, knockout pin 7, first oil releasing path 32 in the lower die 3, second oil releasing path 60 in the second punch 6, and third oil releasing path 70 in the knockout pin 7. Since oil is smoothly released at the time of press forming, a mass production is made possible with the stable precision of a shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a bulge nipple which is inserted into a hose and receives a fastening force when the intermediate joint is fastened to the hose. More specifically, the bulge nipple is continuously mass-produced by transfer molding. A manufacturing method that can be performed.

[0002]

2. Description of the Related Art For example, when an intermediate joint is fastened to a hose, a nipple is inserted in the hose in order to increase the fastening strength of the intermediate joint under the force of caulking. This nipple needs to have an outer diameter larger than the inner diameter of the hose in order to prevent falling out and ensure positioning, but if the outer diameter of the entire nipple is larger than the inner diameter of the hose, the nipple insertion load will be extremely large. It becomes large and man-hours increase.

Therefore, in recent years, a bulge nipple having a bulge portion in which only the outer diameter of the central portion is increased, and the outer diameter of the general portion on both sides of the bulge portion is slightly smaller than the inner diameter of the hose has been used. According to this bulge nipple, the length of the bulge portion is shorter than before and the outer diameter of the general portion is also smaller than the inner diameter of the hose, so the insertion load is small and it can be easily inserted at a predetermined position in the hose, and it does not come off To be prevented.

A product having a shape like this bulge nipple is generally manufactured by cutting from a pipe material.

[0005]

However, the shape of the bulge nipple has a bulge diameter of about 3.65 mm and a length of about 1 mm.
Some of them are as small as about 7 mm, and in order to manufacture such a bulge nipple by a manufacturing method such as cutting, the number of man-hours is large, the yield and the productivity are poor, and there is a problem in cost.

The present invention has been made in view of such circumstances, and an object of the present invention is to enable mass production with high shape accuracy even with a small bulge nipple.

[0007]

A method for manufacturing a bulge nipple according to the present invention which solves the above-mentioned problems is a bulge nipple having a substantially cylindrical shape and including a general portion and a bulge portion formed by expanding the diameter of the general portion in the center thereof. A manufacturing method, which is a first step of forming a bottomed tubular diaphragm cylinder from a sheet metal by drawing, and a bulge portion is formed by pressing the diaphragm cylinder with a punch to form a bulge cylinder. The second step comprises a third step of punching out the bottom of the bulge cylinder, and the second step comprises a lower die, an upper die, and a first punch for pressing the end surface of the aperture cylinder.
A rod-shaped second punch inserted into the inside of the diaphragm cylinder, a knockout pin that axially presses the bottom of the diaphragm cylinder from the outside, a mold that forms a bulge part of the lower mold, and a mold that forms a general part. A press die having a first oil escape passage opening at the boundary of the surfaces, a second oil escape passage opening at the tip surface of the second punch, and a third oil escape passage opening at the tip surface of the knockout pin. It is characterized by performing using.

[0008]

In the manufacturing method of the present invention, first, in the first step, the drawing cylinder is formed by drawing. This first step is carried out in the same manner as a normal drawing process, and generally, a drawing cylinder having a target length is obtained by drawing several times. A bulge portion is formed on the diaphragm cylinder by pressing in the second step.

Here, working oil is used for press working, but the throttle cylinder may be a cylinder with a bottom and a diameter of several millimeters, and the resistance of the oil accumulated inside or between the die and the work may be used. As a result, it became clear that the processed shape accuracy may be lowered. Therefore, in the manufacturing method of the present invention, the first oil relief passage opening at the boundary between the mold surface forming the bulge portion of the lower mold and the mold surface forming the general portion, and the second oil releasing passage opening at the tip surface of the second punch. The second step is carried out using a press die having an oil escape passage and a third oil escape passage opened on the tip surface of the knockout pin.

By providing the first oil escape passage, the oil between the die surface and the work can be escaped, the shape accuracy of the boundary portion between the bulge portion and the general portion is improved, and sagging is prevented. Further, by providing the second oil escape passage, the oil inside the throttle cylinder can be escaped, and the occurrence of burrs at the bulge portion can be prevented. Further, by providing the third oil escape passage, the length accuracy is improved and the occurrence of burrs at the bulge portion is prevented.

The bulge cylinder having a high shape accuracy obtained in the second step is punched at the bottom in the third step to obtain a bulge nipple.

[0012]

Embodiments will be specifically described below with reference to embodiments. FIG. 1 shows an enlarged perspective view of the bulge nipple manufactured in this embodiment. The bulge nipple 1 has a bulge portion 10 having an outer diameter of 3.65 mm and an outer diameter 3.2 m extending on both sides of the bulge portion 10.
m of the general part 11 and the boundary between the bulge part 10 and the general part 11 is a conical surface part 12. (First step) Prepare a sheet metal 20 having a thickness of 0.5 mm, and
As shown in FIG. 3, the drawing cylinder 2 having a predetermined length is formed by drawing a plurality of times. (Second step) Next, using the press die shown in FIGS. 3 and 4,
A bulge portion 10 is formed in the center of the diaphragm cylinder 2.

This press die comprises a lower die 3, an upper die 4, a first punch 5 for pressing the end surface of the aperture cylinder 2, and an aperture cylinder 2.
It is composed of a cylindrical second punch 6 to be inserted therein and a knockout pin 7. Further, the lower mold 3 is formed with four radial first oil escape passages 32 (only one is shown in the drawing) which are open at the boundary between the bulge surface 30 and the conical surface 31. Further, the second punch 6 is formed with a second oil escape passage 60 having an opening at the tip end surface. Furthermore, the knockout pin 7 is formed with a third oil escape passage 70 that opens at the tip.

First, the diaphragm cylinder 2 is placed in the lower mold 3, and the upper mold 4 and the knockout pin 7 are assembled. Then, the first punch 5 and the second punch 6 press the diaphragm cylinder 2,
The diameter of the diaphragm cylinder 2 is expanded, and as shown in FIG.
0 and a bulge portion 2'having a bulge portion 10 and a conical surface portion 12 along the conical surface 31. At this time, the diaphragm cylinder 2
The oil interposed between the lower mold 3 and the lower mold 3 escapes from the first oil escape passage 32 to the outside. Therefore, so-called sagging failure in which the oil remains and the shape accuracy of the conical surface portion 12 is reduced is prevented. Further, the oil remaining in the throttle cylinder 6 escapes from the second oil escape passage 60 to the outside. Therefore, the throttle cylinder body 2 is excessively pressed by the remaining oil, and burr between the upper die 4 and the lower die 3 is prevented from occurring. Further, the oil interposed between the knockout pin 7 and the throttle cylinder 2 escapes from the third oil escape passage 70 to the outside, so that the length accuracy is ensured and burr is prevented.

The accuracy of the length of the diaphragm cylinder 2 is also important. When the total length of the throttle cylinder 2 exceeds 17.75 mm, burrs are generated, and when it is 17.45 mm or less, sagging failure is observed. Therefore, in order to obtain the above-mentioned effect of the oil escape passage, it is necessary to control the entire length of the throttle cylinder 2 within this range, and if it is out of this range, the effect of the oil escape passage cannot be obtained. (Third step) The molded bulge cylinder 2'is released from the mold by raising the knockout pin 7 after the mold is opened. Then, the bulge nipple 1 shown in FIG. 1 is manufactured by being placed in a punching die (not shown), punching the bottom portion, and curling both end faces by curling.

[0016]

That is, according to the bulge nipple manufacturing method of the present invention, bulge nipples having high precision in shape without defects such as burrs and sagging can be mass-produced continuously and stably by transfer molding using drawing. be able to. Therefore, the productivity is remarkably improved and the production cost is reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of a bulge nipple manufactured according to an embodiment of the present invention.

FIG. 2 is an explanatory view schematically showing a first step of one example of the present invention.

FIG. 3 is a cross-sectional view showing a press die before performing a second step of the embodiment of the present invention.

FIG. 4 is a cross-sectional view showing the press die immediately after the second step of the embodiment of the present invention.

[Explanation of symbols]

1: Bulge nipple 2: Diaphragm cylinder
3: Lower mold 4: Upper mold 5: First punch
6: Second punch 7: Knockout pin 10: Bulge part 1
1: General part 12: Conical surface part 32: First oil escape passage
60: Second oil escape passage 70: Third oil escape passage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tamio Asano 1 Ochiai, Nagahata, Kasuga-cho, Nishikasugai-gun, Aichi Toyoda Gosei Co., Ltd. Toyoda Gosei Co., Ltd.

Claims (1)

[Claims] 1. A method for manufacturing a bulge nipple having a general portion having a substantially cylindrical shape and a bulge portion having a diameter enlarged at the center of the general portion, wherein the squeezing cylinder has a bottom and is formed by drawing a sheet metal. A first step of forming a body, a second step of forming a bulge portion by pressing the throttle cylinder with a punch to form a bulge cylinder, and a third step of punching out the bottom of the bulge cylinder. In the second step, a lower die, an upper die, a first punch that presses an end surface of the diaphragm cylinder, a rod-shaped second punch that is inserted into the diaphragm cylinder, A knockout pin that axially presses the bottom of the throttle cylinder from the outside, and a first oil escape passage that opens at the boundary between the mold surface that forms the bulge portion of the lower mold and the mold surface that forms the general portion. , A second oil escape passage opening at the tip end surface of the second punch and the knockout pin Method for producing a bulge nipple and performing using a press die having a third oil release passage which is opened to the end surface.