JPS6049685A - Deflecting arm device - Google Patents

Abstract

PURPOSE:To vary or inhibit resonance frequency peculiar to a bimorph cell, and to remove or damp an unnecessary vibration by disposing and fixing an elastic member between the fixing end side and free end side of the cell. CONSTITUTION:Each main surface of piezoelectric ceramic cells 11, 12 is covered with electrodes 13-16. The cells 11, 12 are laminated and unified so that the directions of polarization are made the same, thus forming a bimorph cell 17. One end of the cell 17 is fastened and held to a support base 18, and the other end is brought to a free state. Fitting members 21, 22 are disposed at both ends of the upper surface of the cell 17, and a coil spring 23 is hooked. Accordingly, resonance frequency peculiar to the cell 17 is varied or inhibited by the coil spring 23, and an unnecessary vibration is removed or damped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a deflection device using a bimorph piezoelectric element, and particularly to a deflection arm device improved to eliminate or attenuate unnecessary vibrations accompanying deflection.

[Technical Background of the Invention] A bimorph piezoelectric element is formed by laminating and bonding a pair of electrically polarized piezoelectric ceramic elements, and by applying a deflection voltage to each of the piezoelectric ceramic elements, the piezoelectric element can be deflected in its longitudinal direction. Known to be bendable. This J: Umu bimorph piezoelectric element is used.
Deflection arm devices have been developed in recent years. This deflection arm device fixes one end of the bimorph piezoelectric element, allows the other end to bend freely, and deflects the free end side by applying an appropriate voltage.

At this time, the direction and amount of deflection of the bimorph piezoelectric element can be controlled by changing the polarity and magnitude of the applied voltage. Therefore, an example of an application of a deflection arm device using a bimorph piezoelectric element that deflects according to an applied voltage as described above is a video tape recorder (VTR). In a VTR, for example, it is used in conjunction with a rotating head for the purpose of good tracking. That is, such a VTR
The video head is attached to one end of the bimorph piezoelectric element, and an in-cylinder voltage that changes over time is applied to the bimorph piezoelectric element so that the video head scans the center position of the track. This allows proper scanning of the video head.

FIG. 1 is a perspective view showing the configuration of a deflection data 18 device used in a conventional VTR. In this figure, the numbers 1 and 2
1 is a piezoelectric ceramic element made of a piezoelectric ceramic material, and electrodes 3, 4 and electrodes 5, 6 are respectively adhered to the main surfaces of these elements 1.2. The bimorph piezoelectric element 7 is formed by arranging the polarization directions of the piezoelectric ceramic elements 1.2 in the same direction and stacking them together via an adhesive. One end of the bimorph piezoelectric element 7 is fixed to a support base 8 in a rotating drum of a VTR, and a video head (not shown) is attached to the other free end. Then, a predetermined deflection voltage is applied to the bimorph piezoelectric element 7 via the terminal 9.10 so that the electrodes 3 and 6 and the electrodes 4 and 5 have the same polarity, respectively. 1~Rack will be scanned appropriately. As the predetermined deflection voltage, a voltage such as a triangular wave, a rectangular wave, or a sawtooth wave is used, for example.

[Problems with the Background Art] However, when such a deflection voltage is applied to the bimorph piezoelectric element 7, the element 7 is deflected in accordance with the deflection voltage and at the same time has a different deflection from the deflection voltage, that is, an unnecessary deflection. Vibration occurs. For example, bimorph piezoelectric element 7
When a sawtooth wave voltage as shown in FIG. 2(a) is applied to the device, deflection accompanied by unnecessary vibrations as shown in FIG. 2(b) occurs.

This unnecessary vibration is due to a unique resonance frequency due to the material, structure, shape, etc. of the bimorph piezoelectric element 7, and has an adverse effect on the 1-ranking of the video head. Therefore, it is necessary to eliminate or attenuate the unnecessary vibrations.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and relates to a deflection device using a bimorph piezoelectric element, which eliminates unnecessary vibrations that occur with deflection according to a voltage applied to the element with a simple structure. The object is to provide a deflection arm device that can be removed or attenuated.

[Summary of the Invention] 5- In order to achieve the above object, the present invention forms a bimorph piezoelectric element by laminating and bonding a plurality of piezoelectric ceramic elements,
One end of this bimorph piezoelectric element is fixed and held as a fixed end, the other end is a free end that deflects according to the applied voltage, and both ends are fixed between the fixed end side and the free end side. or by providing a flexible member on the bimorph piezoelectric element provided with the elastic member so that the surface of the bimorph piezoelectric element and the elastic member are in contact with each other and fixed together to suppress unnecessary vibrations. There is.

[Embodiments of the Invention] The present invention will be specifically described below with reference to the drawings. Third
4 and 4 relate to the first embodiment of the present invention, FIG. 3 is a perspective view showing the configuration of the deflection arm device, and FIG. 4 is a waveform showing the deflection voltage and its deflection. is a sawtooth wave deflection voltage, and (b'') is its deflection. In these figures, reference numerals 11 and 12 are piezoelectric ceramic elements formed in approximately rectangular plate shapes, and these elements 11, 12
An electrode 13.1'lJJ and an electrode 15.16 are attached to each main surface of the electrode 6-. The polarization directions of the piezoelectric elements 11 and 12 are aligned in the same direction, and the piezoelectric elements 11 and 12 are laminated and bonded via an adhesive to form a bimorph piezoelectric element 17. One end of the bimorph pressure N rope 17 is fixedly held on the support base 18 to serve as a fixed end, and the other end is a free end. Also, the electrode 13.16 and the electrode 14.1
5 are connected through terminals 19 and 20 so that they have the same polarity, and by applying a predetermined deflection voltage to the terminals 19 and 20, the free end of the bimorph piezoelectric element 17 is deflected. There is. On the other hand, on the upper surface of the bimorph piezoelectric element 17, mounting members 21 and 22 are provided on the fixed end side and the free end side. The mounting members 21 and 22 are made of a material such as solder, and are convex members on which one end of a spring can be hooked, and are fixed to the electrodes 13 of the bimorph piezoelectric element 17 by soldering.

A coil spring 23 is disposed on the upper surface of the bimorph piezoelectric element 17 as an elastic member with one end hooked to the mounting member 21 and the other end hooked to the mounting member 22. When the deflection arm device is used as a tracking device for a VTR, for example, a video head or the like is attached to the free end side.

According to the deflection arm device according to the first embodiment of the present invention having such a configuration, the terminals 19 and 20 are connected to each other as shown in FIG. 4(a).
When a sawtooth wave deflection voltage shown in FIG. 2 is applied, the deflection characteristics that the bimorph piezoelectric element 17 responds to are as shown in FIG. That is, the coil spring 23 disposed as an elastic member between the free end and fixed end of the bimorph piezoelectric element 17 can change or suppress the unique resonance frequency, thereby eliminating or attenuating unnecessary vibrations.

FIG. 5 is a perspective view showing the configuration of a deflection arm device according to a second embodiment of the present invention. Note that the same parts and members as in the first embodiment are indicated by the same reference numerals.

In this embodiment, two mounting members 31, 32. and 33 and 34 are fixed to the electrode 13. This mounting member 31.
A coil spring 35 is hooked to 32 and a coil spring 36 is hooked to the mounting members 33 and 34. That is, in this embodiment, two sets of coil springs 35 and 36 are arranged as elastic members in the width direction of the bimorph piezoelectric element 17.

According to the deflection arm device according to the second embodiment of the present invention having such a configuration, since the elastic member is disposed so as to be biased uniformly in the longitudinal direction, it has the same effect as the first embodiment. , unnecessary vibrations can be more effectively removed or damped.

FIG. 6 is a perspective view showing the configuration of a deflection arm device according to a third embodiment of the present invention. Note that the same parts and members as in the first embodiment are indicated by the same reference numerals.

In this embodiment, a plate spring 41 made of a rubber material is disposed as an elastic member on the upper surface of a bimorph piezoelectric element 17 having the same structure as the first embodiment.

This plate spring 41 has a roughly rectangular shape, and is provided with a slit-like notch 42 in the longitudinal direction in the center except for both ends of the rectangle 9. The side is attached to the electrode 13 surface with an adhesive. Note that the cutout portion 42 may not be provided if necessary.

According to the deflection arm device according to the third embodiment of the present invention having such a configuration, in addition to having the same effect as when two sets of coil springs are arranged as in the second embodiment,
Since it is made of a material such as rubber, it can be cut and adjusted so that the unique resonance frequency of the bimorph piezoelectric element 17 can be removed or attenuated.

FIG. 7 is a perspective view showing the configuration of a deflection arm device according to a fourth embodiment of the present invention. In this embodiment, in addition to the same configuration as the first embodiment, a flexible resin 51 is attached as a flexible member to the bimorph piezoelectric element 1 at approximately the center of the coil spring 23.
7 and the coil spring 23 are fixed so as to be in contact with each other. This flexible resin 51 is made of silicon or silicon mixed with metal powder.

10- According to the deflection arm device according to the fourth embodiment of the present invention having such a configuration, in the first embodiment, the coil spring 23
When fixed, the damping effect is determined and difficult to adjust, whereas by changing the amount of flexible resin 51, the degree of damping can be controlled.

Also, by mixing metal powder with this flexible resin,
The degree of elasticity can also be varied.

In each of the above embodiments, the elastic member is disposed on the top surface of the bimorph piezoelectric element, but it may be disposed on the back surface, and the elastic member is not limited to a coil spring or a plate spring. However, it may be made of other shapes or members. Moreover, the flexible member is not limited to silicone resin, etc., and other resins can be used. In particular, in the case of elastic resins, the damping effect can be controlled to some extent simply by fixing the resin to the electrode surface of the bimorph piezoelectric element.

Note that the coil spring is not limited to the mounting member of the embodiment, and other mounting means may be used.

[Effects of the Invention] As explained above, according to the present invention, by disposing and fixing an elastic member between the fixed end side and the free end side of the bimorph piezoelectric element, the unique resonance frequency of the bimorph piezoelectric element can be adjusted. Since the vibration is changed or suppressed, a deflection approximately corresponding to the deflection voltage occurs, and unnecessary vibration can be removed or damped using a simple elastic member. Further, by fixing the flexible member together with the elastic member, the degree of damping can be further easily controlled.

[Brief explanation of the drawing]

1 and 2 relate to a conventional example; FIG. 1 is a perspective view showing the configuration of a deflection arm device used in a VTR; FIG. 2 is a waveform showing a deflection voltage and its deflection; a)
3 shows a sawtooth wave deflection voltage, FIG. 3B shows the deflection thereof, FIGS. FIG. 4 shows the deflection voltage and its waveform showing the deflection; FIG. 4(a) shows the sawtooth wave deflection voltage, FIG. 4(b) shows the deflection, and FIG. A perspective view showing the structure of the deflection arm device, FIG. 6, relates to a third embodiment of the present invention, a perspective view showing the structure of the deflection arm device, FIG. 7, relates to a fourth embodiment of the present invention,
FIG. 2 is a perspective view showing the configuration of a deflection arm device. 11.12... Piezoelectric ceramic element 13.14.15.16... Electrode 17... Bimorph piezoelectric element 19.20... Terminal 23.35.36... Coil spring 41... Plate shape Spring 51...Flexible resin 13- Fig. 2, Fig. 4, Fig. 5, 32. 19 Figure 3

Claims (5)

[Claims] (1) Made by laminating and bonding multiple piezoelectric ceramic elements,
A bimorph piezoelectric element having one end fixedly held as a fixed end and the other end being a free end that deflects according to an applied voltage, and an elastic member having both ends fixed to the fixed end side and the free end side of the bimorph piezoelectric element. A deflection arm device characterized by: (2) The deflection arm device according to claim 1, wherein the elastic member is a coil spring or a plate spring. (3) Made by laminating and bonding multiple piezoelectric ceramic elements,
a bimorph piezoelectric element having one end fixedly held as a fixed end and the other end being a free end that deflects according to an applied voltage; an elastic member having both ends fixed to the fixed end side and the free end side of the bimorph piezoelectric element; An intralayer arm device comprising: a flexible member such that the surface of the bimorph piezoelectric element and the elastic member are both in contact with and fixed to the elastic member. (4) The deflection arm device according to claim 3, wherein the elastic member is a coil spring or a plate spring. (5) The deflection arm device according to claim 3 or 4, wherein the flexible portion is made of silicone resin or silicone resin mixed with metal powder.