JPH06182892A - Manufacture of cylindrical elastic member with slit - Google Patents

Abstract

PURPOSE:To provide a method for manufacturing a novel cylindrical elastic member having a slit in which the slit can be formed simultaneously upon manufacturing of the member and an efficiency of an operation can be largely improved. CONSTITUTION:A slit is formed by disposing a rodlike core 13 for erecting a cutter 15 at one end of a side face in a mold 10, filling an elastic raw material in the mold, forming a cylindrical elastic member on an outer periphery of the core, then removing the member from a cutter side end of the core, and cutting the side of the member by the cutter in this case.

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 cylindrical elastic body having a slit.

[0002]

2. Description of the Related Art For example, in an automobile, various wires and tubes are inserted and wired in a cylindrical elastic body made of rubber or the like. This tubular elastic body is also called a grommet, and has a function of bundling wires and the like and protecting the wires and the like from friction and bending.

Such a cylindrical elastic body is molded by injection molding or transfer molding.
After molding, it is necessary to provide a slit for inserting a wire or the like in the tubular elastic body in the tubular direction of the tubular elastic body.

This slit is formed after the cylindrical elastic body is molded.
It is formed by an operator making an incision with a cutter knife or the like, or by operating a simple pressing machine provided with an incision blade in the tubular direction of the tubular elastic body.

However, these methods are not efficient because the work steps are complicated because they are performed by post-processing. In particular, the former method is extremely troublesome since it requires manual labor, and the cut surfaces may become uneven, resulting in defective products.

[0006]

The present invention has been proposed in view of the above-mentioned problems, and such slits can be formed at the same time as the production of the cylindrical elastic body, and the work efficiency can be greatly improved. An object of the present invention is to provide a method for manufacturing a tubular elastic body having a novel slit that can be improved.

[0007]

That is, the present invention is
A rod-shaped core body in which a blade is erected at one end of a side surface is arranged in a molding die, and an elastic material is filled in the mold to form a cylindrical elastic body on the outer peripheral surface of the core body. The present invention relates to a method of manufacturing a tubular elastic body having a slit, characterized in that the elastic body is pulled out from a blade-side end portion of the core body and a side surface of the tubular elastic body is incised by the blade to form a slit.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of the method of the present invention, and FIG.
Is a perspective view showing a state where a tubular elastic body is formed on the core body, FIG. 3 is a perspective view showing a state where a slit is formed on the tubular elastic body, and FIG. 4 is a sectional view showing another example of the present invention. FIG. 5 is a perspective view showing an example of a jig for extracting the core body, and FIG. 6 is its 6-6.
FIG. 7 is a sectional view taken along line 7-7 of FIG.

FIG. 1 shows an example of a molding die for carrying out the manufacturing method of the present invention. The molding die 10 of this embodiment is an injection molding die including a fixed die 11 and a movable die 12, and a rod-shaped core body 13 arranged between the fixed die 11 and the movable die 12 so as to be able to move forward and backward. is there. The fixed mold 11, the movable mold 12, and the core body 13 form a substantially cylindrical molded product cavity 14.
Reference numeral 18 is a sprue hole, and 19 is a sprue bush.

A blade 15 is erected on one end of the side surface of the core body 13, and the other end is connected to a cylinder device 20 provided outside the machine. The core body 13 is provided between the fixed die 11 and the movable die 12 so as to be able to move forward and backward by the operation of the cylinder device 20. Reference numeral 21 is a holding portion that supports the cylinder device 20, and 22 is a holding plate. The holding plate 22 is provided with a core body insertion hole 23 having a diameter that is the same as or slightly larger than the outer diameter of the core body 13. The core body 13 advances and retracts via the core body insertion hole 23.

An elastic material such as rubber is filled in the molding die cavity 14, and a substantially cylindrical elastic body is formed on the outer peripheral surface of the core body 13. In this embodiment, two moldings are molded in one cavity 14. After the tubular elastic body is molded, the mold is opened. As shown in FIG. 2, on the outer peripheral surface of the core body 13, cylindrical elastic bodies P1, P are formed.
2 remains formed.

Then, the cylinder device 20 is operated to retract the core body 13 from between the fixed die 11 and the movable die 12. The cylindrical elastic bodies P1 and P2 formed on the outer periphery of the core body 13 retreat along with the retraction of the core body 13, contact the holding plate 22 of the cylinder device 20, and prevent further retreat. By further retracting the core body 13, the cylindrical elastic bodies P1 and P2 are extracted from the end of the core body 13 on the blade 15 side. At that time, as shown in FIG. 3, the tubular elastic body P is moved by the blade 15.
1. Then, the side portion of P2 is incised in the cylindrical direction to form the slit S.

Although the slit is formed by moving the core body in this example, the present invention is not limited to this. On the contrary, the core body is fixed and the cylindrical elastic body is provided on the side of the core body on the blade side. You may form a slit in the said cylindrical elastic body by sliding it to and pulling out from a core.

FIG. 4 shows another example of the manufacturing method of the present invention, which is an example of molding a cylindrical elastic body by transfer molding. Reference numeral 30 is a molding die, 31 is a lower die, 32 is an upper die, 33 is a core, and 34 is a cavity.

As shown in the drawing, in the mold 30 already clamped, the material chamber 3 formed in the upper mold 32.
6 is filled with the elastic material M, and the plunger member 37
Is heated and pressed from above the upper mold 32. The pressurized elastic material raw material M is filled in the molded product cavity 34 to form the cylindrical elastic bodies P3 and P4 on the outer peripheral surface of the core body 33.

After molding, the mold is opened and the cylindrical elastic body P3 is opened.
The core body 33 in which P4 is formed is taken out, and the cylindrical elastic bodies P3 and P4 are pulled out from the end portion on the blade 35 side. The blade 3
When the tubular elastic bodies P3 and P4 are pulled out from the core body 33, a slit 5 is formed in a side portion of the tubular elastic bodies P3 and P4.

At this time, by using a jig for extracting the core body as shown in FIGS. 5 to 7, the core body can be extracted and the slit can be formed easily and surely. The core body removing jig 40 includes a main body 41 and lid portions 42, 42 attached to the main body 41 by a hinge 43 so as to be openable and closable.

As shown in FIGS. 6 and 7, the body 4
1 and the lid portions 42, 42 slide only a large-diameter elastic body holding portion 44 that holds the cylindrical elastic bodies P3, P4 formed on the core body 33, and the core bodies formed at both ends thereof. The core holding portions 45, 45 having a small diameter for holding the core body as much as possible. Elastic body holding portion 44 and core body holding portions 45, 4 on the side of the main body 41
5, a continuous groove-shaped blade passage portion 46 is formed.

As shown in FIG. 5, the core body 33 having the cylindrical elastic bodies P3 and P4 formed on the outer circumference is set in the core body holding portions 45 and 45 of the main body 41. Next, the lids 42, 42 are closed to hold the cylindrical elastic bodies P3, P4 in the elastic body holding portion 44, and then the blade 33 of the core 33 is passed through the blade passage portion 46 provided in the main body 41. Pull it out as it passes. Thereby, the blade 35 of the core body 33 causes the cylindrical elastic body P to move.
The cylindrical elastic body P3 is moved while incising the side portions of P3 and P4.
The slit S is formed in P4.

The elastic body holding portion is formed to have a diameter slightly smaller than that of the cylindrical elastic body to be molded without providing the core body holding portion, and the core body is provided between the main body and the lid body when the lid body is closed. Also, a structure in which the tubular elastic body is sandwiched may be used.

[0021]

As shown and described above, according to the method of manufacturing a cylindrical elastic body having a slit of the present invention, the slit can be formed at the same time when the cylindrical elastic body is manufactured. The work efficiency can be greatly improved and the post-process can be rationalized.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of the method of the present invention.

FIG. 2 is a perspective view showing a state where a tubular elastic body is formed on a core body.

FIG. 3 is a perspective view showing a state in which a slit is formed in a tubular elastic body.

FIG. 4 is a sectional view showing another example of the present invention.

FIG. 5 is a perspective view showing an example of a jig for extracting a core body.

FIG. 6 is a sectional view taken along line 6-6.

7 is a cross-sectional view taken along line 7-7 of FIG.

[Explanation of symbols]

 10 Molds 11 Fixed dies 12 Movable dies 13 Cores 15 Blades P1 Cylindrical elastic bodies P2 Cylindrical elastic bodies S Slits

Claims (1)

[Claims] 1. A rod-shaped core body in which a blade is erected at one end of a side surface is arranged in a molding die, and an elastic material raw material is filled in the mold to form a cylindrical elastic body on the outer peripheral surface of the core body. Then, the tubular elastic body is extracted from the blade-side end portion of the core body, and then the side surface of the tubular elastic body is incised by the blade to form a slit, thereby producing a tubular elastic body having a slit. Method.