JPH06155355A - Holding device - Google Patents

Abstract

PURPOSE:To simplify and downsize a mechanism and make holding movement stably and securely without damage to an object by forming robot hands with flexible platy piezoelectric material. CONSTITUTION:A holding device T is installed on a robot arm and hands 4 and 4 of a hand part 1 are positioned near an object W by the arm. In this case, when a voltage is applied between external electrode layer 6,... and internal electrode layers 7 and 7 through leads 13 and 14 from a DC power 12, the holding body of the hands 4 and 4 is bent in the direction of arrow 18. As a result, the object W is held in the hands 4 and 4, and transferred to a specified position by the arm. Because the hands 4 of the holding device T are formed with flexible polymer piezoelectric material, the holding body which forms the top end of the hands 4 and 4 can be deformed by the application of voltage according to the shape of the object W, the object W can be held stably and securely, and the object W may not be damaged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gripping device for handling work, and more particularly to a device for handling fine and lightweight parts such as micro gears and micro lenses.

[0002]

2. Description of the Related Art Conventionally, various gripping devices have been proposed to be attached to the tip of a robot arm. Particularly, those using a piezoelectric bimorph are disclosed in JP-A-61-241082 and JP-A-3-60.
No. 988 is available. Both of them have a structure in which a gripping claw for gripping a work is attached to the tip of a bimorph piezoelectric element, and the feature is that the piezoelectric element is used as a driving source of the gripping claw. Since the piezoelectric element is used as the driving source of the gripping claw, no dust is generated, and the force can be detected by the output of the piezoelectric element, so that the pressing force of the gripping claw can be controlled. By the way, the conventional piezoelectric gripping device has the following drawbacks. That is, <1
> Since the structure is such that the gripping claw is attached to the tip of the piezoelectric element, when the device body is miniaturized, the gripping claw must also be miniaturized. , It is difficult to attach it accurately to the tip of the piezoelectric element. <2> In the case of a PZT-based piezoelectric element, since it is a ceramic, the tip of the gripping mechanism cannot be formed into a curved shape, and the work may not be gripped stably.

[0003]

As described above, the conventional gripping device has the above-mentioned drawbacks <1> and <2>. The present invention has been made in consideration of the above circumstances. For example, a micro gear such as a micro gear or a micro lens,
No dust is generated to handle lightweight parts.
An object of the present invention is to provide a gripping device that can realize a reliable gripping operation.

[0004]

In the gripping device of the present invention, a hand for gripping an article is formed of a flexible plate-shaped piezoelectric material.

[0005]

According to the gripping device having the above construction, it is not necessary to provide a special gripping claw, and the mechanism can be simplified and miniaturized. Moreover, since the hand that holds the article can be deformed according to the shape of the article, the holding operation can be performed stably and reliably. Unlike a ceramic material or a metal material, the hand has good moldability and flexibility, and therefore the hand W is not likely to be damaged.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. 1 and 2 show a gripping device H of this embodiment. That is, the gripping device H includes a hand unit 1 that grips the article W, a hand fixing unit 2 that fixes the hand unit 1, and a power supply unit 3 that applies a voltage to the hand unit 1. Then, the hand part 1 is composed of a pair of hands 4 and 4 provided facing each other at a distance of, for example, 1 to 2 mm. Each hand 4 has two piezoelectric elements 5 and 5 formed in a plate shape and laminated on each other.
And external electrode layers 6 and 6 attached to both outer surfaces of the piezoelectric element 5 and an internal electrode layer 7 interposed between the two piezoelectric elements 5 and 5. As shown in FIG. 2, the hand 4 has a rectangular base body 8 and a needle-like shape (for example, a tip having an apex of an acute-angled triangle) having a length of, for example, 15 mm and protruding from one end of the base body 8. It is composed of a grip body 9. As the piezoelectric elements 5 and 5, a flexible polymeric piezoelectric material such as PVDF (polyvinylidene fluoride) is used. The thickness of these piezoelectric elements 5, 5 is, for example, 1
It is about 5 μm. The external electrode layers 6 and 6 are formed by physical vapor deposition of gold (Au) or silver (Ag). On the other hand, the internal electrode layer 7 is formed by dispersing and mixing conductive powder in an organic adhesive. On the other hand,
The hand fixing portion 2 is formed by stacking and closely fixing a pair of rectangular plate members 10 made of a non-conductive member such as plastic.
8 is glued. In addition, the pair of rectangular plate members 8,
The other end of 8 is provided with circular through holes 10a, 10a. These through holes 10a, 10a are used for temporary fixing for precise positioning as described later. Further, the power supply unit 3 includes a DC power supply 12 for applying a DC voltage,
A first lead wire 13 that electrically connects the cathode of the DC power supply 12 to the internal electrode layers 7 and 7, and a second lead that electrically connects the anode of the DC power supply 12 to the external electrode layers 6 ... It consists of line 14. The polarity of the DC power supply 12 is
It may be reversed depending on the shape and size of the article W. The first lead wire 13 and the second lead wire 14 are connected to the external electrode layers 6 ... Through a conductive rectangular thin piece-shaped conductive tape 15. In addition, the rectangular plate members 10 and 10 described above
Is temporarily fixed by the bolt 16 and the nut 17 with the piezoelectric elements 5 and 5 attached (see FIG. 1) before the main fixing with the adhesive (see FIG. 1). After the article is adjusted so that it can be sandwiched, it is finally fixed by, for example, an instant adhesive. Further, the grips 9, 9 may be formed by, for example, cutting after the main fixing. Next, the operation of the gripping device H having the above configuration will be described.

First, the gripping device H of this embodiment is attached to, for example, an arm of a robot (not shown). Then, with this arm, the hands 4 and 4 of the hand unit 1 are positioned near the article W to be gripped. At this time, the article W
Is in a state of being loosely inserted by the hands 4 and 4.
Next, from the DC power supply 12 through the first lead wire 13 and the second lead wire 14, the external electrode layers 6 ...
A voltage of V, for example, is applied between 7 and. Then, the grips 9, 9 of the hands 4, 4 bend in the direction of the arrow 18. As a result, the article W is gripped by the hands 4 and 4 (see the imaginary line in FIG. 1) and is transferred to a predetermined position by the arm. At this time, if an adhesive substance such as glycerin is applied to the inner surfaces of the grips 9, 9 in advance, the article W is less likely to slip and a more reliable gripping operation is possible.

Thus, the gripping device H of this embodiment is
Since the hands 4 and 4 are made of a flexible polymer piezoelectric material such as PVDF (polyvinylidene fluoride), the gripping bodies 9 and 9 forming the tips of the hands 4 and 4 are applied with a voltage. Since it can be deformed according to the shape of the article W, the article W can be stably and reliably gripped. Further, since the hands 4 and 4 have flexibility, there is no risk of damaging the article W. Furthermore, in the gripping device H of this embodiment, the hands 4, 4 main body are connected to the piezoelectric elements 5 ...
Since it is formed only by itself, the gripping claw is unnecessary, and the mechanism can be simplified and miniaturized. Also, the through hole 10
The tips of the grips 9, 9 can be surely positioned by utilizing a and 10a.

In the above embodiment, the gripping device H
It illustrates the case where is attached to the robot arm.
You may attach to the drive mechanism M for exclusive use as shown in FIG.3 and FIG.4. That is, in this embodiment, the gripping device H
Is attached to the tip of a leaf spring 21 provided laterally on the support column 20 so as to be rotatable in the direction of the arrow 22.
The leaf spring 21 is displaced in the direction of the arrow 25 by the pair of left and right swing bimorphs 24, 24 via the wires 3, 23, and the vertical swing bimorph 27 by the wire 26.
The displacement is made in the direction of arrow 28 by. According to the displacement of the leaf spring 21, the gripping device H can be linearly moved in the arrow 22 direction and can be rotated in the arrow 28 direction.

Further, in the above embodiment, the hand fixing portion 2 is composed of the pair of plate members 8 and 8, but the hand portion 1 may be fixed to, for example, one rod-shaped member.

[0011]

In the gripping device of the present invention, since the hand for gripping an article is formed of a flexible plate-shaped piezoelectric material, it is not necessary to provide a gripping claw specially, and the mechanism is simplified and miniaturized. Can be measured. Moreover, since the hand that holds the article can be deformed according to the shape of the article, the holding operation can be performed stably and reliably. Furthermore, unlike the ceramic material and the metal material, the hand has flexibility, so there is no risk of damaging the article W.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a gripping device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a hand portion of a gripping device according to an embodiment of the present invention.

FIG. 3 is a side view showing a usage mode of the gripping device according to the embodiment of the present invention.

FIG. 4 is a front view showing a usage mode of the gripping device according to the embodiment of the present invention.

[Explanation of symbols]

1: Hand part, 2: Hand fixing part, 3: Power supply part, 4: Hand, 5: Piezoelectric element, 6: External electrode layer, 7: Internal electrode layer, 9: Grasping body.

Claims (3)

[Claims] 1. A hand portion provided with a pair of hands facing each other, at least one of which is made of a plate-shaped piezoelectric material having flexibility, a hand fixing portion for fixing the hand portion, and a voltage applied to the hand. A gripping device comprising: a power supply unit that detachably grips an article by applying and deforming the gripping device. 2. The gripping device according to claim 1, wherein the hand is made of a piezoelectric polymer material. 3. A hand is formed by stacking a plurality of plate-shaped piezoelectric elements, an internal electrode layer is formed at a boundary between the plate-shaped piezoelectric elements, and an external surface is formed on an outer surface of the plate-shaped piezoelectric element. A gripping device, wherein an electrode layer is formed, and by applying a voltage between the internal electrode layer and the external electrode layer, the hand is deformed in a direction for gripping an article.