JPH06218811A - Method of forming groove on sheet-like member - Google Patents

Abstract

PURPOSE:To provide a method of easily and accurately forming a groove on a sheet-like member comprising a thermoplastic resin. CONSTITUTION:In a method of forming a groove 19a on a sheet-like skin 19 comprising a thermoplastic resin, a pressing member 22a having a shape corresponding to the shape of the groove 19a is pressed against the sheet-like skin 19 by a predetermined force while ultrasonic waves are applied to the pressing member to melt the skin, thus the groove 19a is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a groove in a sheet-like member made of thermoplastic resin.

[0002]

2. Description of the Related Art As a conventional one of this kind, there is one shown in FIGS. 4 to 6, for example (Actual Kaihei 4-151).
345). In FIG. 4, reference numeral 1 is an instrument panel, and the instrument panel 1 is provided with an airbag device 2 on the passenger side. As shown in FIG. 5, the airbag device 2 includes an airbag 4 inside an accommodating portion 3 and an inflator 5 for deploying the airbag 4.
Is stored and the airbag 4 is covered with an airbag door 6.

This airbag door 6 is made of a core material 7 made of two hard plastic products having a double door shape, a foam 8 made of synthetic resin such as urethane foam, and a thermoplastic made of vinyl chloride resin. The sheet-like epidermis 9 has a three-layer structure. This sheet-like skin 9
Has a groove 9a extending in the horizontal direction on the back surface side. A method of forming the groove 9a in the sheet-shaped skin 9 will be described. The sheet-shaped skin 9 formed into a predetermined shape by powder slush or the like is made so that the back surface thereof faces upward, and the groove 9a is to be formed by a heating blade. 10 is placed on the support base 11 so as to be right below, and then the heating blade 10 is lowered to melt the sheet-like skin 9 while pressing it to form a V-shaped groove 9a having a constant depth. I am trying to form.

When the inflator 5 is actuated by a vehicle collision and the airbag 4 is deployed, the airbag 4 is pushed by the airbag 4, the core material 7 is opened, and the sheet-like outer skin 9 is broken from the groove 9a, and the airbag door is opened. 6 opens outward, whereby the airbag 4 deploys between the occupant and the windshield and protects the occupant.

[0005]

However, in such a conventional one, high precision is required to form the groove 9a in the sheet-like skin 9 of about 1 mm, but the heating blade 10 is used. Therefore, depending on the temperature of the heating blade 10,
Since the molten state of the groove 9a of the sheet-like skin 9 is different,
Temperature control is required, but this temperature control is difficult.

Therefore, an object of the present invention is to provide a method for easily and accurately forming a groove in a sheet-shaped member made of a thermoplastic.

[0007]

In order to solve the above problems, the present invention provides a method for forming a groove in a sheet-shaped member made of thermoplastic resin, wherein a pressing member having a shape corresponding to the groove shape is formed into the sheet. The groove is formed by applying ultrasonic waves to the shape-shaped member while applying a predetermined force to the shape-shaped member to melt it.

[0008]

[Operation] According to such means, it is possible to easily and accurately form the groove having a predetermined shape only by controlling the frequency of the ultrasonic wave and the applied pressure. Since the temperature is controlled as in the past by controlling the heater and the like to a constant temperature, it is difficult to finely adjust the temperature.

[0009]

EXAMPLES The present invention will be described below based on examples.

1 to 3 are views showing an embodiment of the present invention.

In this embodiment, an equilateral triangular V-shaped groove 19a having a depth of about 0.5 mm is formed on the back surface side of a sheet-like skin 19 having a thickness of about 1 mm as a sheet member made of thermoplastic resin. It is formed by such a method.

First, a 50/60 Hz electric signal from a power source is converted into a 20 KHz electric signal by the oscillator 21.

This weak signal is amplified to the required power by the amplifier. All electric circuits are solid-state circuits and are modularized.

In addition, an AFC circuit (automatic frequency control circuit), an ALC circuit are provided so that the device operates normally even when the load changes.
Circuits (automatic load compensation circuit) etc. are also built-in.

The 20 KHz electric signal is transmitted to the converter 22 and converted into mechanical vibration energy.

The conversion method includes an electrostrictive type and a magnetostrictive type. The conversion efficiency of the magnetostrictive type is about 50%, while that of the electrostrictive type is 1%.
It shows a high conversion efficiency of 90% or more. The amplitude on the output side of the converter 22 is 60 mμ. Output 2.4KW, frequency 1
The vibration energy of 5 kHz is transmitted to the sheet-like outer skin 19 through the pressing member 22a formed at the lower end of the horn 23. A mechanical amplitude converter called a booster 24 is provided between the converter 22 and the horn 23, and is designed to effectively transfer electric energy to the sheet-like skin 19.

The horn 23 is a half-wave resonator and its material is made of titanium alloy, and the pressing member 22a is
Corresponding to the groove 19a to be formed, it has a regular triangular shape having a height of 0.5 mm. Then, when the pressing member 22a is pressed against the sheet-like outer skin 19 with a pressing force of 5 kg / cm ² , ultrasonic waves are applied as described above, and this portion is melted by the frictional force here, and the thickness is 1 mm. An equilateral triangular groove 19a having a depth of 0.5 mm is formed in the sheet-like skin 19 of FIG.

As shown in FIG. 3A, the groove 19a may be formed along a U-shape whose corners are R-shaped, or as shown in FIG. 3B. , H shape can also be formed.

By thus forming the groove 19a using ultrasonic waves, if the frequency, pressure, etc. are set to a predetermined value without the need to control the temperature of the heating blade 10 as in the conventional case, Even if it is continuously used, a constant groove 19a can be formed.

In the airbag device using such a sheet-like skin 19, when the airbag is deployed, the groove 1 is formed.
The sheet-like outer skin 19 is cut along the line 9a and opens along the U-shape or the H-shape.

In the above embodiment, the V-shaped groove 19 is used.
Although a is formed, it is not limited to such a shape, and it is needless to say that it may be formed in a U shape or the like.

[0022]

As described above, according to the present invention, since the groove is formed by using the ultrasonic wave, the predetermined shape can be obtained only by controlling the frequency and the applied pressure of the ultrasonic wave. It has a practically useful effect that the groove can be formed easily and accurately.

[Brief description of drawings]

FIG. 1 is a front view of a groove forming apparatus and the like showing an embodiment of the present invention.

FIG. 2 is a front view showing a groove forming state of the same embodiment.

FIG. 3 is a back view of the sheet-like skin in the state where grooves are formed showing the same embodiment.

FIG. 4 is a perspective view of an instrument panel showing a conventional example.

FIG. 5 is a cross-sectional view showing an airbag device of the conventional example.

FIG. 6 is a cross-sectional view showing a groove formation state of the conventional example.

[Explanation of symbols]

 19 Sheet-like skin (sheet-like member) 19a Groove 22a Pressing member

Claims (2)

[Claims] 1. A method for forming a groove in a sheet-shaped member made of a thermoplastic resin, wherein a pressing member having a shape corresponding to the groove shape is pressed against the sheet-shaped member with a predetermined force to apply ultrasonic waves and melt. And a groove is formed in the sheet-like member. 2. The sheet-shaped member is a skin that is provided inside a passenger compartment of an automobile and covers an airbag, and the groove is a groove that is divided by receiving a force when the airbag is deployed. The method for forming a groove in a sheet-like member according to claim 1.