JPH02131922A - Ultrasonic tool horn - Google Patents

Abstract

PURPOSE:To immediately manufacture a horn having arbitrary horizontal length with no requirement of performing trial and error by a method wherein a means to apply the vibration of the predetermined frequency at the middle of an input surface and slots, each one of which is formed at the antinodal point of the natural flexural vibration mode of a bridge part, are equipped with. CONSTITUTION:The horn concerned consists of four pillar parts, which are separated from each other by three slots 3a, 3b and 3c, and two bridge parts, which connect the upper and lower portions of the pillar parts. The pillar parts can be regarded as vibrating beams having the length of l, the constant thickness and the respective heights of h1 and h2. By providing slots at the antinodal points of flexural vibration, the flexural vibrating beam is not apt to be excited and consequently flexural vibration is suppressed and no flexural vibration component is superposed, resulting in making the vertical vibration of an output surface evenly. Since the flexural vibration component, which intrinsically has horizontal component, is suppressed, the output surface vibrates only vertically and the vibration of the output surface has no horizontal component.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an ultrasonic welding tool horn used for welding plastics, or an ultrasonic power soter tool horn used for cutting various materials.

(Prior Art) When welding the welding surfaces of plastic sheets using an ultrasonic welding machine, for example, a plate-shaped tool horn shown as an example in FIG. 8 is used. Here, 3 r[! I slot 3a
．． Four pillars separated by 3b and 3c -1+ w
l, l'll + wa and connect this above and below 2
It consists of two bridge parts h1 and h2, is connected to an excitation means (not shown) by a female screw 4, has a half wavelength length in the vertical direction, and the output surface 2 vibrates in the opposite phase to the input surface. Slots 3a, 3b. 3c is arranged so that all four pillars have the same dimensions. This type of tool horn is standard and well known in the industry, and its design is widely disclosed in the prior art discussed above. A problem encountered in the past is that the output surface 2 of the tool horn, whose length in the left-right direction is approximately half a wavelength or more, exhibits uneven vertical vibration displacement and vibration components in the left-right direction. Ideally output side 2
The purpose is to make the vibrational displacement in the vertical direction constant regardless of the position in the left-right direction, and to make the vibration component in the left-right direction zero regardless of the position in the left-right direction. In order to do so, according to the experience of the inventors, the internal pillars 2 and 2 are equal and the external pillars 1 and 1 are also equal, but the internal and external pillars must be different. many. However, the method for determining this was unclear and required a long period of trial and error.

In order to make the vertical vibration displacement of the output surface almost uniform, there is a method of providing a bar 7 on the side of the input end to increase the mass (Unexamined Japanese Patent Publication).
It is known that slots are provided (Japanese Patent Application Laid-Open No. 1983-84226, etc.) and slot slots are known.
However, I have not found anything that can be generalized and applied to horns with arbitrary lengths in the left and right directions.

(Problems to be Solved by the Invention) Problems to be solved by the present invention are the nonuniform vertical vibration displacement of the horn output end face and the presence of horizontal vibration components accompanying the vertical vibration. This size varies depending on the point of interest and shows a certain distribution. The unevenness of vertical vibration and the presence of horizontal vibration components both cause the magnitude of the vibration power transmitted from the horn to the item to vary depending on the location, leading to uneven welding and causing practical problems. . However, the above problem depends on the mass distribution inside the horn,
The result was brought about by an extremely delicate balance of mass distribution, and required skill and a long period of trial and error.

(Means for solving the problem) In order to solve the above problem, in the present invention, a half-wavelength resonator is The dimensional section is a rectangular resonance, which is a dimensional section, which is a means of giving a predetermined frequency vibration in the center of the input surface, and the abdomen of the bridge part of the bridge. It shall be equipped with a slot. The present invention provides a tool horn that can easily position the horn for a horn having an arbitrary length of half a wavelength or more in the left-right direction, and that can vibrate uniformly up and down.

The present invention was made by focusing on the fact that such a plate-shaped horn potentially contains a unique bending vibration mode in addition to an element that vibrates vertically due to its shape.

The horn shown in Figure 1 consists of three horns 3a, 3b, 3
It consists of four pillars separated by C, and two bridges connecting them at the top and bottom.

Each of these bridge sections has a height of FII+ hz and a length of C.
, it can be considered as a flexural vibrating beam with constant thickness.

The vibration direction of this bending vibration is the vertical direction in FIG. That is, the present inventors believe that the reason why uniform longitudinal vibration cannot be obtained is due to the bridge portions h, h, and h in FIG. When considered as a beam, it was discovered for the first time that the flexural vibration of the natural mode closest to the used ultrasonic 'eL frequency is excited and superimposed on the longitudinal vibration.

Therefore, it was found that flexural vibration can be suppressed by providing a slot at a position that does not promote natural flexural vibration, that is, at the antinode of the flexural vibration. The position of the antinode can be easily calculated from the Bernoulli-Euler theoretical formula for bending vibration as follows.

The vibration displacement distribution is based on the standard function 3. It is understood from 3. is the order m, the reference constant is α, and y is the dimensionless coordinate in the left and right direction (
1) It can be generalized from Eq.

3-”'l/(sinα,-sinhαlI)
((sinα0−sinhαm)(cosαlI
y +coshαm y)− (cosα+++
COShαlI) (sinαlly+sinhα
．． y)) (1) Figure 7 shows the results. The height h of the flexural vibration beam is determined by the formula 2rcf= (a, "/l!")・R・c, where f is the resonant frequency of free flexural vibration and R is the radius of rotation of the flexural vibration beam.
It is obtained from (2). Here, in the case of a rectangular cross-section filled vibrating beam, R = f (h2/12), C: longitudinal sound velocity of the thin rod, and P is the length, so h = (4π・IN − f − 1 ”)/ (c.
α. Z).

The upper and lower bridges shall, in principle, have the same turning radius.

(Function) As described above, when the slot is provided at the antinode position of the bending vibration, the bending vibration is suppressed because there is a gap and it is difficult to excite the bending vibration beam, and the bending vibration components are not superimposed, so the vertical vibration of the output surface becomes uniform. Furthermore, although the bending vibration component essentially has a horizontal component, since this is suppressed, the output surface only has vertical vibration and does not have a horizontal component. (Example) A horn implemented according to the present invention , we obtained results that agree well with experiments. FIG. 2 shows a horn with a slot provided in the position according to the present invention, and FIG. 3 shows a horn not according to the present invention.
The results of analysis using the finite element method are shown in Fig. 4 and Fig. 4, respectively. FIGS. 5 and 6 show still other embodiments of the present invention. According to the present invention, the vertical vibration displacement ξa of the output surface 2 in FIGS. 2, 5, and 6 is almost constant regardless of the horizontal position, and the horizontal vibration component ξ8 is in the horizontal direction. is close to zero regardless of the position.

This almost fulfills the ideal intention mentioned above. On the other hand, in the case of FIGS. 3 and 4, which are not based on the present invention, the vertical vibration displacement ξ is not constant depending on the horizontal position.
It can be seen that the vibration component ξ8 in the left and right direction is large.

According to the tool horn of the present invention, as is clear from the above, vertical vibration displacement on the output surface can be made uniform.

It should be noted that the present invention includes not only the step-shaped one shown in FIG. 1, but also a taber-shaped one whose cross section perpendicular to the vertical direction is entirely rectangular, and a straight one.

(Effects of the Invention) A horn of any length in the left and right direction that exhibits uniform vertical vibration displacement can be immediately produced for each type of material and ultrasonic frequency used, without the need for trial and error, resulting in practical improvements. Significant.

Due to its bilateral symmetry, only the right half from the center line is shown.

1. ．． ．． ．． Input surface, 2. ．． ．． ．． Output surface, 3a, 3b
,3c,. ．． ．． Slot, 4. ．． ．． ．． Female screw! ．． ．． ．．
．． Length in left and right direction, L. ．． ．． ．． Vertical length, h+, hz
．． ．． ．． ．． Bridge part, w,, w2, w,, w4,,, pillar part, ξ. ．． ．． ．． Vibration component in the vertical direction, ξc. ．． 5. Vibration component in the left and right direction.

[Brief explanation of drawings]

Fig. 1 shows an example of the tool horn of the present invention when the number of slots is 3, Fig. 2 is an analysis diagram of the vibration mode of the tool horn,
Figures 3 and 4 are analysis diagrams of a tool horn not according to the present invention, and Figures 5 and 6 are vibration modes of the tool horn in other embodiments of the present invention when the Slonoto number is 4 and 5, respectively. FIG. FIG. 7 is a bending vibration mode diagram. FIG. 8 shows a conventional standard tool horn. In addition, the analysis diagram is centered around the driving point, and the patent applicant: Ultrasonic Gyokugyo Co., Ltd.'$J Garden I3 Diagram ¥2 Diagram'Stalk 4 sides 15I2 Rod 71 Certain by

Claims (1)

[Claims] A resonator with a rectangular cross section dimensioned to resonate as a half-wavelength resonator for longitudinal waves of a predetermined frequency that pass vertically from an input surface to an output surface disposed on the opposite side. , comprising means for applying vibration at a predetermined frequency at the center of the input surface, and slots at positions corresponding to the abdomen of the natural flexural vibration mode of the bridge, and the length in the left and right direction is equal to or more than half a wavelength. Ultrasonic tool horn.