JPS60115337A - Bulging method of thin cylinder drawing goods - Google Patents

Abstract

PURPOSE:To simplify an opening punching device, to reduce a punched removed material, and to improve a yield by forming an opening of a small diameter on the bottom face of a bottomed cylinder part formed from a plate material, and thereafter, forming a straight cylinder part, and forming a bulging part in the outside circumferential of its tip part. CONSTITUTION:A flange part 11, a containing part 12 and a bottomed cylinder part 13a are formed by drawing a plate material, and an opening 15 of a smaller diameter d2 than an inside diameter d1 of the bottomed cylinder part 13a is formed concentrically on a bottom face 14 of the bottomed cylinder part 13a by a piercing process. A remaining bottom part 14a left in the circumferential edge part of the opening 15 is made straight by bending it by an extending process, and a communicating straight cylinder part 13b is formed. Subsequently, a punch 20 having a larger outside diameter d3 than an inside diameter d1 of the straight cylinder part 13b is inserted from the containing part 12 side, a thickness of a cylinder part 13c is made roughly uniform by a squeezing process, and its thin part is removed. Moreover, a bulging part 18 is formed in the outside circumference of the tip of the cylinder part 13c by a bulging process, and a desired connector 10 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a bulge processing method for forming a bulge for a hose stop on the outer periphery of the tip of a thin cylindrical drawn product.

BACKGROUND TECHNOLOGY In general, water-cooled engines installed in automobiles connect a cooling waterway formed in the cylinder block to a radiator installed at a location remote from the engine body using inlet and outlet hoses to cool the cooling water. Cooling water is circulated between the water channel and the radiator. By the way, the portion where the hose is connected to the cylinder block is connected via a connector l as shown in FIG. This connector 1 has a flange portion 3 that is attached to a cylinder block 2 via bolts (not shown), and a housing portion 5 for a thermostat 4 is formed which bulges out in a substantially hemispherical shape from the inner cylinder edge of the flange portion 3. Further, a cylindrical portion 6 is provided protruding from the storage portion 5, and a hose 7 is fitted to the tip of the cylindrical portion 6.

A bulging portion 8 is formed on the outer periphery of the distal end of the cylindrical portion 6 by bulge processing, and the hose 7 is stopped by this bulging portion 8.

Since the connector 1 needs to have a large-diameter flange portion 3, the connector 1 is formed by drawing a thin iron plate. That is, the connector 1 is conventionally formed as a thin cylindrical drawn product through the steps shown in FIGS. 2(4), 2(B) and 2(C').

First, as shown in Figure (A), the plate material is squeezed by a pressing process, and the flange portion 3. Storage section 5. A cylindrical portion 6 is formed.

This cylindrical portion 6 is formed into a bottomed cylindrical shape in the pressing step, and the bottom surface of the cylindrical portion 6 is formed in the cutting step shown in FIG.
The outer periphery of the distal end portion where a is present is cut by a cam mechanism or the like to connect the cylindrical portion 6. Then, a bulging portion 8 was formed on the outer periphery of the tip of the cylindrical portion 6 communicated in this manner by rolling or the like in a bulging process shown in FIG. 1(C).

However, in such conventional methods, it is necessary to remove the bottom surface 6a in the cutting process in order to perform the final bulge process, but as described above, the outer periphery of the cylindrical part 6 is cut, so the cutting process This is done using a complicated mold such as a dancing cam mechanism, which increases the cost of the mold. Further, since the outer periphery of the cylindrical portion 6 is cut, the removed material 9 on the bottom surface 68 that is removed becomes thicker, resulting in a problem that the yield rate deteriorates.

OBJECTS OF THE INVENTION In view of the above-mentioned conventional problems, the present invention makes it possible to remove the bottom surface with a simple device by opening only the bottom surface and extending the periphery of this opening when communicating the cylindrical portions. It is an object of the present invention to provide a bulging method for thin-walled cylindrical drawn products, which reduces the size of the removed material and improves the yield.

Structure of the Invention In order to achieve the above object, the method of bulging a thin-walled cylindrical drawn product of the present invention includes a pressing step of drawing a plate material to form a bottomed cylindrical portion, and a pressing step of forming a bottomed cylindrical portion by drawing a plate material. A piercing process in which an opening with a smaller diameter than the inner diameter of the cylinder part is formed on the bottom surface of the bottomed cylinder part, and a remaining bottom part remaining at the periphery of the opening formed in this piercing process is made to have the same diameter as the outer circumference of the cylinder part. There is an extension step in which the tube is bent in the opposite direction to make it straight, an ironing step in which a punch with a diameter larger than the inner diameter of the tube is inserted into the straight tube obtained by this stretching step, and a This process includes a bulging process in which a bulging portion is formed on the outer periphery of the tip of the obtained straight cylindrical portion.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 3 shows a method for bulging a thin-walled cylindrical product according to an embodiment of the present invention, and will be described using a connector 0 for connecting a cooling water circulation hose to a cylinder block as in the conventional method. That is, the iron plate is squeezed in the pressing process shown in FIG. The storage portion 12 and the bottomed cylindrical portion 13a are molded, and the bottom surface 14 of the bottomed cylindrical portion 13m formed in this pressing process is pierced in a piercing process shown in FIG. Inner diameter d1 Small diameter d2
An opening 15 is formed concentrically with respect to the cylindrical portion 13a.

However, the removal material 16 generated in this piercing process is removed from the opening 1.
5 and has a flat plate shape with a smaller diameter than the diameter of the cylindrical portion 13a. Next, the remaining bottom part 14a remaining at the peripheral edge of the opening 15 in the piercing process is bent outward in the extension process shown in FIG. A straight cylindrical portion 13b is formed. In addition, in this stretching process, there are four parts 17 on the outer periphery of the bent part of the remaining bottom surface 14a.
A is formed, and a thin portion 17 is formed in the straight cylindrical portion 13b by this recess 17a. Figure 3 (l
2 shows an ironing process in which the thin wall portion 17 formed in the stretching process is eliminated and the wall thickness is approximately equalized, and the straight cylindrical part 13 is
A punch having an outer diameter d5 larger than the inner diameter d1 of b is inserted into the straight cylindrical portion 13b from the storage portion 12 side. In this embodiment, the punched outer diameter d5 is approximately 0.3 mm larger than the inner diameter d1 when the inner diameter d1 of the straight cylindrical portion 13b is between φ and φ. It is formed to have a large diameter of 0.5 m. By carrying out this straining step, the wall thickness of the cylindrical portion 13c is strained and made approximately equal, and the thin portion 17 is removed. Next, a bulging part 18 is formed on the outer periphery of the tip (upper part in the figure) of the cylindrical part 13c, whose wall thickness has been made uniform by the ironing process, by a bulge process shown in the figure. A connector lO is formed.

By the way, the bulge process is performed using a bulge apparatus shown in FIG. That is, between the bulge device and the punch 31 which is fitted into the housing part 12 of the connector 10 and the lower end of the cylindrical part 13c and holds the connector lO, and which is moved up and down with respect to the punch 31 and held by the punch 31. A die 32 is provided for pressing the tip of the cylindrical portion 13c of the connector IO. The pressing part of the cylindrical part 13c of the die 32 is formed with concave wings that follow the outer shape of the upper half of the bulging part 12, and the punch 31 has an annular part that holds the outer periphery of the flange part 11 of the connector IO. A nest 34 is fixedly installed. Further, between the punch 31 and the die 32, there are holding surfaces 35, 358 that follow the outer shape of the connector IO, and a cam slide 36° that is divided into two in the left and right direction in the figure and moves toward and away from each other. 36a is provided. The holding surfaces 35, 35a of the cam slide 36°36a
A recess 37 along the lower outer shape of the bulge 18 at the upper end.
is formed. Historically, a pylon 3B having a diameter substantially equal to the inner diameter of the tip of the cylindrical portion 13c projects from the center of the recess formed in the die wing. Then, the unfinished connector 10a obtained by the ironing process shown in FIG. 3) is inserted into the punch 31. ness) 34
At the same time, the cam slides 36 and 361L are held close to the outside of the connector 10m, and the die 32 is lowered to press the upper end of the cylindrical portion 13c of the connector 10a. Then, the outer periphery of the upper end of the cylindrical portion 13c bulges out along the concave wings 37, forming a bulged portion 18. At this time, the connector 10 is inserted into the punch 31. It is supported by the cam slide to prevent deformation, and the pilot door prevents the bulging portion 18 from falling inward. Therefore, as a thin-walled cylindrical drawn product according to this embodiment, In the bulging method for forming a bulging portion in the cylindrical portion 13c of the connector IO, the work of connecting the bottomed cylindrical portion 13m in the piercing process is simply the work of punching the bottom surface 14. Therefore, the device used in the piercing process is significantly simplified, and the punched out removal material 16 is inserted into the cylindrical portion 13.
Since the inside diameter d1 is smaller than that, the yield is improved with smaller products.

In addition, in this embodiment, the bulging portion 1 is formed in the cylindrical portion 13c in the bulging process.
By using the bulge device when forming the bulge 8, the bulge 18 is formed by one downward movement of the die 32,
The work efficiency is significantly improved compared to the conventional case in which the bulge is formed by roll processing, which is performed while rotating a loan around the outer periphery of the cylindrical portion.

However, before proceeding to the bulge step, the present invention performs the process shown in FIG. 3 (
Since the stretching process shown in FIG. 0) is followed by the ironing process shown in FIG. Incidentally, if the bulge process is performed directly from the extension process without performing the above-mentioned ironing process, stress will be concentrated on the thin part 17 of the cylindrical part 13b due to the pressure accompanying the descent of the die 31, and the shape of the bulging part 18 will change. becomes distorted.

As described in detail, in the bulging method for thin-walled cylindrical drawn products of the present invention, in order to communicate the bottomed cylindrical portion formed in the pressing process, the bottom surface is made in accordance with the inner diameter of the cylindrical part in the piercing process. Since a small-diameter opening is formed and the remaining bottom surface of the periphery of this opening is stretched straight in the extension process, the piercing process can be performed with a simple device, resulting in low equipment costs.
The reduction in the size of the removed material produced by the piercing process improves the yield, and together with this, it is possible to achieve a significant cost reduction of the product. Historically, by inserting a squeezing process between the stretching process and the final bulging process, the thin part of the cylinder formed in the stretching process was removed, resulting in a substantially uniform wall thickness. Therefore, various excellent effects such as being able to form a bulged portion of a predetermined shape by the bulge process are achieved.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a thin-walled cylindrical drawn product, and Figure 2 (4). (B) e (C) is an explanatory diagram showing step by step bulge processing of a conventional thin-walled cylindrical drawn product, Figure 3 (4), (B) t
(c) t @s (This is an explanatory diagram showing step by step an example of bulge processing of a thin-walled cylindrical drawn product of the present invention, and Figure 4 is an enlarged cross-sectional view of Figure 3 (C) for the middle part s. , Fig. 5 is a sectional view showing an embodiment of a bulge device used during bulge processing. 1.10... Connector (thin cylindrical drawing product), 6, 13
a, 13 b, 13 e--cylindrical part, 6 m,
14...Bottom surface, 8, 18...Bulging part, 9.16
... Removal material, 14a... Remaining bottom surface, 15... Opening.

Claims (1)

[Claims] ill A pressing step of squeezing the plate material to form a bottomed cylindrical portion, a piercing step of forming an opening with a smaller diameter than the inner diameter of the cylindrical portion on the bottom surface of the bottomed cylindrical portion formed in this pressing step, and this piercing step. an extension step of bending the remaining bottom portion remaining at the periphery of the opening formed in the cylindrical portion outward to the same diameter as the outer periphery of the cylindrical portion to make it straight; and a straight tube obtained by this extension step. a squeezing process of inserting a punch with a diameter larger than the inner diameter of this cylindrical part;
A bulging method for thin-walled cylindrical drawn products, characterized in that the bulging process is performed in addition to a bulging process of forming a bulge on the outer periphery of the tip of the straight cylindrical part obtained by this ironing process.