JPH078203Y2 - Piezoelectric element displacement amplification mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a mechanical amplification mechanism that amplifies displacement of a piezoelectric element using a piezoelectric element as a driving source.

[Conventional technology]

Conventionally, this type of mechanical amplification mechanism is used particularly in printers, relays, and the like.

FIG. 10 is a diagram showing an example of a piezoelectric element displacement amplification mechanism of a dot impact printer (Japanese Patent Laid-Open No. 59-175386). Substrate 2 having both end faces of piezoelectric element 21 and mounting holes 24a
Lever arms 25 are connected to both end faces of 4 by hinges 22 and 23 for transmitting displacements due to expansion and contraction of the piezoelectric element 21, respectively.

Further, the lever arm 25 is connected by brazing, spot welding or the like so as to sandwich a beam 26 having a print needle 27 as an operating element at its tip portion, and the substrate 24 is provided with an adjusting screw 28 for the back stop of the beam 26. Has been. By applying a voltage to the piezoelectric element 21 in the mechanism configured as described above, the displacement 21a of the piezoelectric element 21 is moved via the hinge 22 to each of the lever arms 2.
5, the displacement is magnified at the tip of the lever arm 25. That is, the beams 26 supported by being sandwiched by the lever arms 25 are displaced in the axial direction at both ends thereof,
Deforms in a direction perpendicular to the displacement applied to both ends, as explained in the well-known buckling theory, and the maximum displacement 29 occurs in the central portion. Therefore, at the time of driving, the beam 26 pushes the printing beam 27 forward to perform printing. After that, the piezoelectric element 21 is restored by stopping the applied voltage, and the beam 26 is a back stop adjusting screw.
Return to 28.

[Problems to be solved by the device]

This piezoelectric element displacement amplification mechanism includes a beam 26 having a print needle 27.
However, since the two lever arms 25 are connected by brazing or spot welding at the joint part that has a groove at the tip, the lever arm 25 and the beam 26 expand and contract due to the thermal influence of the high temperature in the manufacturing aspect. However, the position accuracy of the tip of the print needle 27 is poor, and after assembly, precision adjustment work is required to grind the tip of a considerable number of print needles 27 at the same time, and in brazing work, cleaning work for flux removal is required. Therefore, in spot welding work, quality control using equipment such as weld checkers to maintain strength is essential. On the other hand, in terms of usage, since the printing speed is a high-speed operation of 110 characters / sec or more, concentrated stress acts on the joint portion due to vibration, and fatigue fracture occurs earlier than the heat-cured portion of the heated connection portion.

As described above, the conventional piezoelectric element displacement amplification mechanism has a drawback in that it takes time and effort to connect the lever arm and the beam at the time of manufacture, and the life of the product is short due to the fatigue fracture of the connection part in use. .

[Means for Solving the Problems]

In the piezoelectric element displacement amplification mechanism of the present invention, the beam is connected to the lever arm by rivet fastening.

[Action]

Since the connection between the lever arm and the beam is by rivet fastening, the work is easy and easy to automate, the working time is extremely short, and there is no thermal influence during manufacturing, so there is almost no fatigue damage due to use. A permanent fastening is obtained and the reliability of the product is improved.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a front view of a first embodiment of a piezoelectric element displacement amplification mechanism of the present invention, and FIG. 2 is an enlarged sectional view taken along the line BB in FIG.
FIG. 3 is a plan view of the piezoelectric element displacement amplification mechanism of FIG.

In this piezoelectric element displacement amplification mechanism, lever arms 5 are connected to both end surfaces of a piezoelectric element 1 via hinges 2, and each lever arm 5 is hinged to both side surfaces of a board 4 having a mounting hole 4a at an intermediate portion. 3, the both ends of the beam 6 are connected to the tip of each lever arm 5, and the piezoelectric element displacement 1a is amplified at the center of the beam 6 so that the maximum displacement 8 is generated. The beam 6 is fastened to the lever arm 5 with a round rivet 7.

Piezoelectric element 1 has an extension / contraction direction dimension of 10 mm, a displacement of 1 a of 0.01 mm, a lever arm 5 amplification factor of 5, and a beam 6 length.
When it is set to 50 mm, it is 0 at the center of the beam 6, which is the same as the conventional mechanism.
A piezoelectric element displacement amplification mechanism that can be driven with a maximum displacement of 6 mm was obtained. In addition, applied voltage DC150V, frequency to the piezoelectric element 1.
The life when a frequency of 200 Hz was applied was 10 ^{4 in the} conventional example, but was 10 ⁶ or more in the present example. Therefore, in this embodiment, the riveting operation of the round rivet 7 is a simple operation and is suitable for automation, and the required time is instantaneous and extremely short, so that the manufacturing time can be shortened, and permanent fastening and high reliability can be obtained.

FIG. 4 is a front view of a second embodiment of the piezoelectric element displacement amplification mechanism of the present invention, and FIG. 5 is an enlarged cross-sectional view of the CC cross section of FIG.

This piezoelectric element displacement amplifying mechanism is a piezoelectric element displacement amplifying mechanism which is fastened via a synthetic resin layer 9 when the beam 6 is fastened to the lever arm 5 of the embodiment shown in FIG. 1 by the round rivet 7. In this embodiment, the stress distribution in the fastening portion is more uniform than in the embodiment of FIG. 1 and a longer life can be obtained.

In this embodiment, the piezoelectric element 1 has a voltage of DC150V and a frequency of
The life when 200Hz was applied was 10 ⁸ times or more.

FIG. 6 is a front view of a third embodiment of the piezoelectric element displacement amplification mechanism of the present invention, and FIG. 7 is an enlarged cross-sectional view of the DD cross section of FIG.

In this piezoelectric element displacement amplification mechanism, instead of fastening the beam 6 to the lever arm 5 of the embodiment shown in FIG. 1 with the round rivet 7, the plate rivet 10 is fastened via the flat washer 11 to the piezoelectric element displacement amplification mechanism. . In this embodiment, the lever arm 5 and the beam 6 have the same joint structure at the joint, and high reliability and long life can be obtained.

FIG. 8 is a front view of a fourth embodiment of the piezoelectric element displacement amplification mechanism of the present invention, and FIG. 9 is an enlarged cross-sectional view taken along the line EE of FIG.

This piezoelectric element displacement amplifying mechanism is a piezoelectric element displacement amplifying mechanism in which a thick beam 12 having a different shape in a portion 12a to be fastened to a lever arm 5 is fastened by a round rivet 7 instead of the beam 6 of the embodiment shown in FIG. Is. In this embodiment, the same high reliability and long life as those of the embodiment of FIG. 6 can be obtained, and since there is no flat washer (FIG. 7), the number of parts does not increase and automation in manufacturing is easy.

[Effect of device]

As described above, according to the present invention, the two lever arms for transmitting and amplifying the displacement of the piezoelectric element and the beam are connected to each other by rivet fastening, so that the accuracy adjustment work after assembly and the flux cleaning work can be performed in terms of manufacturing. No need for quality control of welding or welding, process is simplified, work efficiency is improved, and automation of manufacturing is facilitated.Fatigue fracture of the joint part due to thermal influence in use is eliminated and permanent fastening is achieved. Therefore, there is an effect that long life and high reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a front view of a first embodiment of a piezoelectric element displacement amplification mechanism of the present invention, and FIG. 2 is an enlarged sectional view taken along the line BB in FIG.
3 is a plan view of the piezoelectric element displacement amplification mechanism of FIG. 1, FIG.
FIG. 5 is a front view of a second embodiment of the piezoelectric element displacement amplification mechanism of the present invention, FIG. 5 is an enlarged cross-sectional view taken along the line CC of FIG. 4, and FIG.
FIG. 7 is a front view of a third embodiment of the piezoelectric element displacement amplification mechanism of the present invention, FIG. 7 is an enlarged cross-sectional view of the DD cross section of FIG. 6, and FIG.
FIG. 9 is a front view of a piezoelectric element displacement amplifying mechanism according to a fourth embodiment of the present invention, FIG. 9 is an enlarged sectional view taken along line EE of FIG.
The figure is a front view of a conventional example of a piezoelectric element displacement amplification mechanism. 1 ... Piezoelectric element, 1a ... Displacement of piezoelectric element, 2,3 ... Hinge, 4 ... Board, 4a ... Mounting hole, 5 ... Lever arm,
6 ... Beam, 7 ... Round rivet, 8 ... Maximum displacement, 9 ...
Synthetic resin layer, 10 …… Plate rivet, 11 …… Flat washer,
12 ... Atypical beam, 12a ... part.

Claims (1)

[Scope of utility model registration request] 1. A piezoelectric element is connected to one end of each of two lever arms whose intermediate portions are connected to both side surfaces of a substrate, and a beam is connected to the other end of each of the two lever arms. A piezoelectric element displacement amplification mechanism for expanding the displacement of a piezoelectric element by the lever arm and transmitting it to the beam, wherein the beam is connected to the lever arm by rivet fastening.