JPH0469870B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tool horn for an ultrasonic welding machine that is used for applying ultrasonic vibration to and bonding thermoplastic plastics.

[Conventional technology]

When ultrasonically welding thermoplastics,
In order to perform uniform welding, it is necessary that the surfaces of the tool horn that come into contact with the plastic (processing surface, radiation surface) have substantially uniform longitudinal vibration displacement in the same phase.

When the length of the weld formed on the plastic is longer than 1/4 of the wavelength of the vibration of the tool horn, as shown in Fig. It is known that the radiation surface 2 cannot be vibrated uniformly unless the slit 8 extending in the direction is provided in accordance with the length of the width l. The vertical width L, the width s of the slits, the number of slits, the width between the slits w, the excitation surface 1 and the radiation surface 2 from both ends of the slit 8.
Since there is no design method for determining the distance t, we experimentally cut it to an approximate size, vibrated it, adjusted the operating frequency, and tried to make the vibration displacement uniform on the radiation surface 2. I made it by re-sharpening it by mistake. In order to solve this problem, from the perspective of dealing with boundary value problems, we analyzed vibration modes and stress distribution using the finite element method, and demonstrated the above-mentioned longitudinal width L, slit width s, and slit width. number, width between slits w,
A method for determining the distance t, etc. from both ends of the slit 8 to the excitation surface 1 and the radiation surface 2 is proposed in Japanese Patent Publication No. 62-58899.

However, in a tool having such a slit 8, cracks may occur at both ends of the slit 8 due to use, and the tool may become unusable. The cause of this is thought to be that repeated stress is concentrated in this area, and as a countermeasure, attempts have been made to give the inner surfaces of both ends of the slit 8 a mirror finish, but a complete solution has not yet been achieved.

Also, since this tool horn utilizes a resonance phenomenon, the width l takes discrete values depending on the operating frequency, and depending on the length or shape of the welded part, the plastic may be scratched or the weld may be incomplete. There were times when I felt like this.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a tool horn which does not have slits and can therefore prevent the occurrence of cracks, and whose width l can be freely determined regardless of the operating frequency.

[Means to solve the problem]

Means for solving the problems according to the present invention is a plate-shaped body having a vertical width of 1/2 wavelength, a horizontal width of 1/4 wavelength or more, and a thickness of 1/6 wavelength or less at the wavelength of the ultrasonic vibration used. The excitation surface has the above-mentioned vertical and horizontal widths, and forms a symmetrical mountain shape with a high center when viewed from the front and back, and between the foot of the mountain and the radiation surface on the front and back, there is a space in the width direction. A tool horn for an ultrasonic welding machine is formed in a row, with a convex part in the center and concave parts on the left and right sides, which are formed symmetrically and the same on the front and back, and the vertical width is equal to the wavelength of the ultrasonic vibration used. A plate-shaped body with a width of 1/2 wavelength, a width of 1/4 wavelength or more, and a thickness of 1/6 wavelength or less, with the excitation surface having the above-mentioned vertical and horizontal widths at the center when viewed from the front and back. and a symmetrical waveform having peaks on the left and right sides thereof, and in a line in the width direction between the trough of the waveform and the radiation surface on the front and back sides,
A convex portion is located at a position corresponding to the central peak of the waveform,
A concave portion is formed at a position corresponding to a trough from the middle of the slope of the waveform, a convex portion is formed at a position corresponding to the apex on the left and right sides of the central apex of the waveform, and a convex portion is formed symmetrically from the front side corresponding to the waveform. and a tool horn for an ultrasonic welding machine that is formed identically on the back.

[Effect]

The present invention analyzes vibration modes with a vertical width of 1/2 wavelength.
We limited our analysis to plate-shaped bodies with a width of 1/4 wavelength or more and a thickness of 1/6 wavelength or less, and performed numerous simulations using the finite element method. The vibration mode analysis diagrams shown in Figures 7 and 8 are the vibration modes in the right half of the excitation point when a vibrator is coupled to the center of the excitation surface of a plate-shaped tool horn. This is what is shown. In these figures, solid lines indicate a stationary state, and dotted lines indicate a moving (vibrating) state. FIG. 7 shows a case where a tool horn made of a rectangular plate with a flat surface and no slits is vibrated, and it can be seen that it is greatly distorted at both ends (the right end in the figure, the same applies hereinafter). FIG. 8 shows the vibration mode of the embodiment shown in FIGS. 1 to 3, in which the excitation surface 1 is formed in a symmetrical chevron shape with the portion where the vibrator is coupled as the top when viewed from the front 3. It has been discovered that if the same convex portions 5 and concave portions 6 are formed on the front surface 3 and the rear surface 4 in correspondence with these peaks, the radiation surface 2 can be vibrated uniformly. Figure 9 shows
The excitation surface 1 of a plate with a flat front face 3 and a flat back face 4 has a corrugated shape with peaks formed at the center and both ends and valleys in between. In this case, almost no vibration occurs on the radiation surface 2 facing the valley, and large vibrations occur on both sides, indicating that the radiation surface 2 does not vibrate uniformly.
Fig. 10 shows the vibration mode of the embodiment shown in Figs. ,
Convex portions 7 are provided at the portions corresponding to the peaks at both ends of the excitation surface 1.
This shows that if a concave portion 6 is formed in a portion corresponding to the area from the foot of the central peak to the valley of the excitation surface 1, the radiation surface 2 will vibrate uniformly.

〔Example〕

Embodiment 1 FIGS. 1 to 3 show an embodiment corresponding to claim (1). The excitation surface is one side along the longitudinal direction of a plate-shaped body whose vertical width L is 1/2 wavelength, width l is 1/4 wavelength or more, and thickness t is 1/6 wavelength or less, which is the wavelength of the ultrasonic vibration used. 1, and the excitation surface 1 is formed into a symmetrical chevron shape with a high center when viewed from the front 3 and back 4 having a vertical width L and a horizontal width l. A convex portion 5 at the center and concave portions 6 on the left and right sides of the convex portion 5 are arranged in a row in the width l direction between the hem of the mountain and the radiation surface 2 on the front surface 3 and the rear surface 4, and are symmetrically arranged on the front surface 3 and the rear surface 4. are formed identically. The recessed portion 6 is deeper at both end halves than at the center. The material of this figure is duralumin, the frequency is 18.362KHz, the thickness is T45mm, and the width is
It was obtained by simulation with l255mm and vertical width L160.2mm. Regardless of whether the horizontal width l and the vertical width L are somewhat large or small, the excitation surface 2 vibrates almost uniformly in the same way.

Embodiment 2 FIGS. 4 to 6 show an embodiment corresponding to claim (2). The excitation surface 1 is one side along the longitudinal direction of the plate-like body whose vertical width L is 1/2 wavelength, width l is 1/4 wavelength or more, and thickness T is 1/6 wavelength or less. When viewed from the front side 3 and the back side 4 having a vertical width L and a horizontal width l, the waveform is formed into a symmetrical waveform having a center and peaks on the left and right sides of the center. Front 3 and back 4
Between the valley of the waveform and the radiation surface 2, a convex part 5 is arranged in a row in the width direction at a position corresponding to the central peak of the waveform, and a convex part 5 is provided at a position corresponding to the valley from the middle of the slope of the waveform. A concave portion 6 is formed on the front surface 3 and a convex portion 7 is formed on the front surface 3 and the rear surface 4 in a symmetrical manner corresponding to the waveform. . Convex portions 7 on both left and right ends
The center half is slightly lower than the outer half. The material of this figure is duralumin, the operating frequency is 18.360KHz, the thickness is T40mm, the vertical width is L152mm,
This was obtained by simulation with a width of 400 mm. In this case as well, the radiation surface 2 can be vibrated uniformly even if the vertical width L and the horizontal width l are somewhat large or small. In addition, if the width l is even longer, in order to make the vibration uniform on the radiation surface 2, valleys and peaks are formed continuously on the left and right by simulation, and corresponding recesses are formed on the front surface 3 and the back surface 4. It is possible to form a convex portion or a convex portion.

〔Effect of the invention〕

According to the tool horn of the present invention, since there is no slit, cracks are less likely to occur. Therefore, tool life can be significantly extended. Since there is no slit, the width of the tool horn can be adjusted regardless of the operating frequency, so a tool horn that matches the required welding length can be provided. When aligning the radiation surface with the welding surface and cutting out a part of the way, if there was a slit, the area from the end of the slit to the notch would be thinner, which caused cracks to easily occur, but this problem is also eliminated.

[Brief explanation of the drawing]

Figure 1 is a front view of Example 1 of the tool horn of the present invention, Figure 2 is a top view of Figure 1, Figure 3 is a right side view of Figure 1, and Figure 4 is Example 2 of the tool of the present invention. Fig. 5 is a top view of Fig. 4, Fig. 6 is a right side view of Fig. 4, and Fig. 7 shows a flat plate with no protrusions, recesses, or slits on the front and back. A simulation diagram when vibration is caused on the excitation surface 1, FIG. 8 is a simulation diagram of Example 1, and FIG. 9 is a simulation diagram of a plate with a flat front and back surface having two symmetrical valleys on the excitation surface 1. FIG. 10 is a simulation diagram of the second embodiment, FIG. 11 is a front view of a conventional tool horn having a slit, and FIG. 12 is a right side view of FIG. 11. L...Length, l...Width, T...Thickness, 1...
Excitation surface, 2... Radiation surface, 3... Front, 4... Back, 5... Convex, 6... Concave, 7... Convex, 8...
...Slit, s...Slit width, w...Width between slits, t...Distance from both ends of the slit to the excitation surface and radiation surface.

Claims (1)

[Claims] 1. The wavelength of the ultrasonic vibration used, the vertical width is 1/2 wavelength,
It is a plate-shaped body with a width of 1/4 wavelength or more and a thickness of 1/6 wavelength or less, and the excitation surface is a symmetrical body with a high center when viewed from the front and back with the above-mentioned vertical and horizontal widths. It has a mountain shape, and has a convex part in the center in a row in the width direction between the base of the mountain and the radial surface on the front and back sides,
A tool horn for an ultrasonic welding machine in which concave portions are symmetrically formed on the left and right sides and are the same on the front and back sides. 2 The wavelength of the ultrasonic vibration used, the vertical width is 1/2 wavelength,
It is a plate-shaped body with a width of 1/4 wavelength or more and a thickness of 1/6 wavelength or less, and the excitation surface has the above-mentioned vertical and horizontal widths, as seen from the front and back, the center and the tops on the left and right of it. A convex portion is formed in a row in the width direction between the trough of the waveform and the radiation surface on the front and back sides, and is located at a position corresponding to the central peak of the waveform. A concave portion is formed at a position corresponding to a trough from the middle of the slope, a convex portion is formed at a position corresponding to the apex on the left and right of the central apex of the waveform, and a convex portion is formed in a symmetrical manner corresponding to the waveform on the front and back sides. Tool horns for ultrasonic welding machines that are identically formed.