JPH0341909Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an ultrasonic welding machine that uses vibrations at ultrasonic frequencies.

[Conventional technology]

Generally, an ultrasonic welding machine is constructed as shown in FIG.

Figure 2 shows the configuration of the main parts of a conventional ultrasonic welding machine, where 1 is an oscillation power source, 2 is a frame, 3 is a vibrator, 4 is a horn, 5 is a vibrating rod, and 6 and 6' are specimens. ,
7 is a mounting seat, and 8 is a pressurizing cylinder.

That is, the electric vibration of the ultrasonic frequency output given by the oscillation power source 1 is converted into mechanical vibration displacement by the vibrator 3 attached to the frame 2, and the mechanical vibration displacement is amplified by the horn 4, and the result is shown by the arrow A. It acts in the vibration direction shown in . Furthermore, the horn 4
A vibrating rod 5 is fixed almost at the center to the tip of the horn and is arranged in a direction perpendicular to the vibration direction of the horn, and a welding tip 5a is attached to the vibrating rod 5 integrally with the vibrating rod by bolting or the like. It is installed.

Further, the specimens 6 and 6' are both welded, and the lower specimen 6' is attached to the pressure cylinder 8.
It is fixedly attached to a mounting seat 7 which can be raised and lowered at a speed.

In such a device, when the specimens 6 and 6' are held between the vibrating rod 5 and the mounting seat 7, and then pressurized by the pressure cylinder 8 and electrical vibration is applied from the oscillation power source 1, the vibrator 3 generates a mechanical vibration. vibration displacement occurs. This is amplified by the horn 4 and transmitted to the central part of the vibrating rod 5, and along with this, the tip 5a at the tip of the vibrating rod 5
is vibrated and the specimen 6 is also vibrated and displaced along with the tip of the vibrating rod, so a high-frequency contact sliding action is performed between the contact surfaces of the specimens 6 and 6', and the sliding action cleans the contact surface. The specimens 6, 6' are welded by frictional heat and pressure on the contact surfaces.

[Problem that the invention attempts to solve]

As described above, the conventional ultrasonic welding machine has the following problems because the tip of the vibrating rod is vibrated and displaced by applying vibrational displacement to the center of the vibrating rod 5. I was getting used to it.

That is, the vibrating rod 5 is normally set so that its entire length has the same natural frequency as the vibration displacement applied to the central portion attached to the tip of the horn.

However, in practice, when vibration is applied from the horn 4 to the central portion of the vibrating rod 5, resonance vibration in the lateral direction is generated.

This is shown, for example, by the broken line in FIG. In other words, the vibration mode W is an example of the third-order resonance vibration mode of the vibrating rod. Here, W _B1 and W _B2 are the antinodes of the vibration mode. In this way, especially at both ends of the vibrating rod, a large vibrational displacement is generated because the antinode portions are located.

From this, the vibration displacement on the side where the chip 5a is attached is suppressed to a certain value by the pressurizing force and the frictional force between the specimens 6 and 6', but the end opposite to the side where the chip is attached is free. Because of this, a large amplitude is generated during resonance. Therefore, the belly part shown
A large bending stress acts on the position between W _B1 and W _B2 , which may cause problems such as fatigue breakage of the vibrating rod, so chip 5a
The disadvantage was that the vibration displacement could not be increased.

[Means for solving problems]

The present invention was developed by focusing on the points mentioned above, and consists of an elastic body positioned according to the antinode of the vibration mode in order to suppress vibration displacement on the free end side of the vibrating rod, especially the resonance vibration component. It is constructed by providing a bushing.

[Effect]

Now, considering the natural frequency ω of a vibrating rod as shown in FIG. 2, that is, a rod with both ends free and the center supported, it is expressed by the following equation.

ω=(mi) ²・R・C/ ² …(1) In equation (1), (mi); prescribed constant determined by cos(mi)・cosh(mi)=1 i; order of vibration mode (i= 1, 2, 3...) R: radius of rotation of the moment of inertia of the cross section of the vibrating rod C: speed of sound in the material of the vibrating rod; total length of the vibrating rod.

In equation (1), the natural frequency is unrelated to the vibration amplitude, so even if the vibration amplitude of the vibrating rod is suppressed by an elastic bush, the natural frequency will not change.

In this way, by suppressing the amplitude at the antinode position of the vibration mode as described above, the bending stress can be reduced without affecting the natural frequency, making the vibrating rod particularly useful.

Note that if the bush itself is not an elastic body, that point will serve as a fulcrum and the natural frequency will change.

Therefore, by using an elastic body, the slight vibration displacement at this position is allowed to prevent the vibration mode from changing, and the buffering effect suppresses excessive amplitude and prevents bending stress from becoming excessive. I can do it.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

〔Example〕

FIG. 1 shows the main structure of an embodiment of the present invention, in which 9 is a support plate, and 10 is a cylindrical bush made of an elastic body such as rubber. In the figure, the same reference numerals as in FIG. 2 indicate the same components.

In FIG. 1, a support plate 9 is arranged to hold a bush 10, one end of which is fixed to the frame 2, and the other end of which has a cylindrical shape, into which the bush 10 is fitted. In that issue 10,
Its inner diameter has a slight interference with the outer diameter of the vibrating rod 5 to support the vibrating rod 5 without any gaps, and furthermore, the vibrating rod support point is the antinode of the vibration mode of the vibrating rod 5,
Therefore, it is set at a position corresponding to the belly portion W _B2 shown in FIG. The function of such a configuration is as follows.

That is, when power is supplied to the oscillation power source 1 and vibration displacement is applied to the vibrating rod 5 via the horn 4, the vibration displacement on the side opposite to the tip mounting side above the center of the vibrating rod 5 is as follows.
Since the belly portion of the vibration mode is supported by the bush 10, its amplitude is suppressed by the elastic displacement and vibration absorption effect of the bush 10, and large bending stress is not applied to the vibrating rod, allowing it to function without any problems.

[Effect of idea]

As explained above, according to the present invention, by appropriately suppressing the free end side of the vibrating rod, it is possible to select a large and optimal vibration displacement of the tip without being constrained by the amplitude of the free end side. This makes it possible to provide a practically capable device that can improve welding performance.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the main part configuration of an embodiment of the present invention, and FIG. 2 is a diagram showing the main part configuration for explaining a conventional example. 1... Oscillation power supply, 2... Frame, 3... Vibrator, 4... Horn, 5... Vibration rod, 6, 6'...
Specimen, 9... Support plate, 10... Bush, W _B1 ,
W _B2 ...Antinode of vibration mode.

Claims (1)

[Scope of utility model registration request] An oscillation power supply that generates electrical vibrations at an ultrasonic frequency, a vibrator that converts the electrical vibrations into mechanical vibration displacement, a horn that amplifies the mechanical vibration displacement, and a horn disposed at the tip of the horn that is perpendicular to the horn vibration direction. In an ultrasonic welding machine having a vibrating rod whose central portion is attached to the vibrating rod, a position that becomes an antinode on the free end side of the vibrating rod opposite to the tip in the vibration mode when mechanical vibration is applied to the vibrating rod. An ultrasonic welding machine characterized in that the is gripped and held via a bush made of an elastic body supported by a support plate attached to a frame.