JPS6176295A - Joint device using bimorph element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a joint device using the bending motion of a polymer piezoelectric bimorph element as a driving source, such as a pseudohand or a pseudopod.

Joint equipment for robots, automatic control equipment, etc. f! Regarding tK.

(Prior Art) Generally, the arm bending means of a joint device uses a motor, a linear actuator, etc. as a drive source, and generates arm motion using the joint as a fulcrum either directly or indirectly through a power transmission device such as a gear. A compulsory method is used. This method has the disadvantage that the volume double zone of the drive source and the power transmission device becomes large, and the mechanism of the joint device becomes complicated. It is also possible to use materials such as bimetals or shape memory alloys as a drive source, but both require heat supply and require complicated operations such as operation in the subtitle range, the need for heat dissipation, and the method of supplying the heat source. There are many problems. As a means of solving the problems of the above method of driving the arm using the joint as a fulcrum, a piezoelectric bimorph element is used as the driving source, and when an electric field is applied, the joint is moved by the Noshimol 7 elements. 〇 (Problem to be solved by the invention) Ceramic materials such as lead zirconate titanate and barium titanate have been known as materials for piezoelectric bimorph elements, but ceramics are brittle and thin. It has the disadvantage that it is easily bent when formed, and when forming a bimorph, it becomes thick in practical terms, and when an electric field or field is applied, it exhibits only a small bending due to the relationship described later.

An object of the present invention is to simplify the structure of a joint device by using a bimorph element made of a polymeric piezoelectric material and moving an arm using a joint as a fulcrum using bending motion when an electric field is applied as a driving source. There is K.

(Another means to solve the problem) As a polymeric piezoelectric material, polyvinylidene fluoride or vinylidene fluoride can be copolymerized with an unsaturated monomer such as tetrafluoroethylene monomer or 67fluoroethylene chloride. There are copolymer compositions. There are also organic-inorganic bonded piezoelectric materials in which these polymeric materials are mixed with ceramic powders such as lead zirconate titanate, lead zirconate titanate tin niobate, and lead zirconate antimony niobate. These polymeric piezoelectric materials are easy to mold and can be formed into thin films by commonly used plastic extrusion methods. Moreover, since the bimorph element can be formed using a thin film, the amount of bending of the bimorph element can be increased by applying an electric field.

After extrusion molding, the polymer piezoelectric film is made into a thin film through processes such as rolling and stretching, and electrodes of metal such as aluminum are formed on the front and back surfaces by methods such as vapor deposition or painting.
After applying an electric field of 5 to 15 φ DC between both electrodes and maintaining it for a predetermined period of time, the electric field is applied and cooled for a short time to decentralize and mold.

In FIG. 1, one bimorph element consists of two polymer piezoelectric films 2, 2', each of which has an electric current [4].
, 4' are formed, and the film 2°/ is an Ot electrode bonded by an adhesive layer 6.

4' is connected to the DC snow field 5. The polarization directions of the film 2° are in the same direction as shown by the solid arrows,
When electric fields in opposite directions are applied from the power source 5, the film 2 expands and the film 2 contracts, causing the bimorph element to bend in the direction of the dotted arrow. In the case of the circuit connection shown in FIG. 1, the radius of curvature R of the bent bimorph element 1 is calculated as follows: ignoring the thickness of the thin adhesive layer 3, t is the floating distance of each film 6n), V is the voltage (egg.emu)
>* When d is a piezoelectric constant (cg+s, arnu), R='/3· is expressed as U1/d. FIG. 2 is a schematic diagram showing the longitudinal displacement tU of the bimorph element 1 when the bimorph element 1 is bent and deformed to 1'.

A bimorph element 1 with a length L (equipment) has a voltage V (egg
, esu) K forms a radius of curvature R (bullet) and bends 1
', the displacement position U in the length direction of the bimorph prince 1 is expressed as U=L-2Rsin T-/2R. For example, d=100X10-'cgs, esu
r L=2m r t = 0.0010m, V=10
0V C=0.353 cgs-esu), R=
2cm.

U=0.08cnt. In order to increase the displacement "tl-U", the radius of curvature R must be decreased, that is, the voltage V.

In addition to increasing the voltage constant d, it is important to reduce the film thickness t (Special 1).In ceramic bimorph elements, it is difficult to mold t thinly, and even if it can be molded thinly, However, since they are brittle, there is a high risk of them breaking when bent, but polymer piezoelectric bimorph elements compensate for this drawback.

Figure 6 shows the basic structure of the joint device, in which both ends of the pi-self element 1 are connected to a freely rotating support 8 on
．． 8', the arms 7 and 7' are connected by a fulcrum 9 that serves as a joint. The displacement position of the linear distance between the fulcrums 8 and 8 caused by the bending of the bimorph door 1 can be varied by voltage ■, and the angle formed by the fulcrum 9 and the arms 7, 7' and K can also be freely varied by 797 degrees. can. ) in FIG. 3 is a modification of FIG.

7 Both ends of the bimorph element 1 are placed on S' as a freely rotating fulcrum 8
．． Fig. 8' shows the articulation device provided at 8'.

In this case too, due to the bending of the bimorph element 1! 1i18
Can move 8 degrees.

FIG. 4 shows a joint device in which both ends of the bimorph element 1 are held directly at the joint points 10 and 10 at the ends of the arms 7 and 7'. In this case, the bimorph element 1 itself becomes a joint and the arm 7
,7' move.

The arms 7, 7' and the arms 7S, 78' connected thereto are made of a suitable structural material, such as metal, depending on the application.

Plastics, ceramics, wood, etc. can be used, and the fulcrums 8, 8', 9 can be formed by a commonly used mechanism. The material is selected depending on the application of the joint device that requires one bimorph element.

It is possible to use any shape or structure formed from a plurality of films, and it is also possible to use a plurality of bimorph elements 1 in parallel. Furthermore, this joint device is connected in series,
It is also possible to construct a device consisting of a plurality of joint devices.

(Embodiments) The present invention proposes a joint device using the bending motion of a polymer piezoelectric bimorph element as a driving source, and various embodiments will be described below.

FIG. 5 shows an arm 7.7 attached to a fulcrum 9 serving as a joint, both ends of the bimorph element 1 held by universal joints 8t, 8t, these attached to fulcrums 8, 8 of arms 7, 7, and a bimorph element 1
This is a joint device in which the wire electrodes are connected to a power source 5.

FIG. 6 is a modification of FIG. 5, in which the bimorph element 1 is mounted in a joint device in which the position is on the extension of the arm relative to the fulcrum 9.

FIG. 7 shows the embodiments shown in FIGS. 5 and 6 and the bi-directional structure shown in FIG. 4.
This is an artificial hand consisting of a plurality of joints in which a structure in which the morph element 1 is used as a direct joint is combined. Bimorph elements 1a, 1b, 1c attached to each joint.

Id, 1e are connected to power supplies 5a, 5b + 5ct 5d, 5e. Each power supply is connected to and controlled by the computer 10, and an appropriate voltage is applied to each power supply at a predetermined timing, applied to each bimorph element, and the artificial hand is can move freely.

(Effects of the Invention) The present invention is a joint device using a polymer piezoelectric bimorph element as a driving source.The bimorph element can be made extremely lightweight and compact, and can be easily operated by applying an electric field. It is possible to have a simple structure for the joint device that moves the arm using the fulcrum as the fulcrum.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a joint device using the bimorph element of the present invention, Figure 2 is a schematic diagram showing the displacement of the bimorph element in the longitudinal direction, and Figure 3 (2) is an explanatory diagram of the operation of the joint device. ,
Figure 4 is a diagram showing the relationship between the joint device of the present invention and the arm, and Figures 5-
FIG. 7 is a plan view of an embodiment of the joint device of the present invention. 1: Bimorph element 2: Polymer piezoelectric film 6: Adhesive layer a, 4': *Pole 5:' source 7.7, 7S, 7S: Arm 9: Joint 10: Computer half 1 Figure 2/ Figure 3 (A) Figure 3 (B) Figure 4 Figure 5 Figure 6 Figure 7 C

Claims (1)

[Claims] A joint device whose drive source is a bimorph element made of multiple polymeric piezoelectric films.