JPH06269178A - Inch worm - Google Patents

Abstract

PURPOSE:To provide an inch worm in which a piezoelectric element at an elongating part is not subjected to excess external force even upon variation of the shape of an object. CONSTITUTION:Inch worms 39a, 39b comprise multilayer piezoelectric elements 32a, 32b secured to an external structure 30, and electromagnets 31a, 31b for clamping a magnetic shaft 34 which can move relatively to the external structure 30. Variable couplings 37a, 37b, 38a, 38b are interposed between the piezoelectric elements 32a, 32b and the electromagnets 31a, 31b in order to alter the orientation of the electromagnets 31a, 31b with respect to the piezoelectric elements 32a, 32b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inchworm for transferring an object or itself by alternately repeating a clamping operation and an extension operation.

[0002]

2. Description of the Related Art An inchworm mechanism (also simply referred to as an inchworm) is well known as a method for realizing the movement of an object or the movement of oneself by utilizing a minute deformation generated by applying a voltage to a piezoelectric element. is there. A basic configuration example of this mechanism is shown in FIG.

In FIG. 5, three piezoelectric sillings 1, 2, 3 are arranged outside a metal shaft 4 which is a guide rail. The piezoelectric cylinder 1 and the piezoelectric cylinder 3 are deformed in a direction sandwiching the metal shaft 4 by applying a voltage,
The piezoelectric cylinder 2 is deformed in the longitudinal direction of the metal shaft 4 by applying a voltage. Therefore, when a voltage is applied to the piezoelectric cylinder 1 and the piezoelectric cylinder 2 and no voltage is applied to the piezoelectric cylinder 3, the piezoelectric cylinder 1 clamps the metal shaft 4 and the piezoelectric cylinder 2 expands. Therefore, the right end of the inchworm mechanism is It extends to the right in FIG.

In this state, if a voltage is applied to the piezoelectric cylinder 3 and then the voltages of the piezoelectric cylinder 1 and the piezoelectric cylinder 2 are released, the expanded state of the piezoelectric cylinder 2 returns (that is, the piezoelectric cylinder 2 contracts). The left end of the inchworm mechanism is also displaced rightward in FIG. That is, if the application and release of the voltage described above is repeated, the entire inchworm mechanism moves on the metal shaft 4 in the right direction in FIG.

On the contrary, if the inchworm mechanism is fixed to the outside by some means and the constraint of the metal shaft 4 to the outside is removed, the metal shaft is moved leftward in FIG. To be done.

FIG. 6 shows an example of a so-called electromagnetic piezoelectric inchworm using an electromagnet instead of the clamp piezoelectric cylinders 1 and 3 shown in FIG. In FIG. 6, the external structure 2
A guide hole 25 is bored at 0, and the magnetic body shaft 24 is fitted inside the guide hole 25. Electromagnet 2
1 is fixed to the laminated piezoelectric element 22, and the laminated piezoelectric element 22 is fixed to the side wall 26a of the recess 26 of the external structure 20. In FIG. 6, the electromagnet 21 and the piezoelectric element 2
The drive device 2 is omitted. Also, the magnetic shaft 24
, The gap between the external structure 20 and the electromagnet 21 is emphasized, but they are actually very close to each other.

When the magnetic material shaft 24 is transferred with the configuration shown in FIG. 6, a current is applied to the electromagnet 21 to cause the magnetic material shaft 24 to attract the magnetic material shaft 24, and a voltage is applied to the laminated piezoelectric element 22 in this state. The element 22 extends. As a result, the magnetic shaft 24 moves leftward in FIG. After that, when the application of the current to the electromagnet 21 is stopped and the voltage to the laminated piezoelectric element 22 is released, the electromagnetic piezoelectric inchworm returns to the initial state. By repeating the above process, the magnetic body shaft 24 continues to be transferred to the left in FIG.

When transferring the magnetic body shaft 24 to the right side, first, a voltage is applied to the laminated piezoelectric element 22 to extend it, and in this state, a current is applied to the electromagnet 21 to attract the magnetic body shaft 24. To do. After that, the voltage of the piezoelectric element 22 is released, and then the application of the electric current of the electromagnet 21 is stopped,
This process is repeated.

[0009]

In the inchworm mechanism having the above-mentioned structure, the clamp parts such as the clamp piezoelectric cylinders 1 and 3 (FIG. 5) and the electromagnet 21 (FIG. 6), the metal shaft 4 and the magnetic body. The relative positions of the shaft 24 and the like to be clamped are set to be geometrically substantially the same. The object to be clamped is generally a straight line, a plane, or an arc having a constant radius of gyration. This is because the extension part and the clamp part forming the inchworm must be rigidly connected, and the mechanical characteristics of the piezoelectric element are weak against external force in the shear direction perpendicular to the deformation direction.

As described above, there are great restrictions on the shape and movement of the object to be clamped. In particular, it is difficult to positively change the shape and movement of the object to be clamped in the direction in which the mechanical characteristics of the piezoelectric element are weak. In some cases, it was damaged due to non-uniformity in shape (undulation during long length, roughness of processing accuracy, etc.).

The present invention has been made in consideration of such a point, and it is possible to reduce the application of an excessive external force in the direction in which the mechanical characteristics of the piezoelectric element are weak, and thereby the shape and operation of the object to be clamped can be reduced. The purpose is to provide an inch worm that can expand the range of freedom of choice.

[0012]

SUMMARY OF THE INVENTION According to the present invention, an extended portion which is fixed to a structure and which is composed of a laminated piezoelectric element, and an object which is movable relative to the structure are formed by convex curved surfaces. And a variable joint having a spherical element or an elastic element that is provided between the extension section and the clamp section and that can change the orientation of the clamp section with respect to the extension section. An inchworm, and an extension part that is fixed to the structure and that is composed of stacked piezoelectric elements, and a clamp part that clamps an object that is movable relative to the structure with a convex curved surface. The inchworm is characterized in that an electric storage element that stores electric charges discharged from the piezoelectric element is connected to the extension portion.

[0013]

According to the first aspect of the invention, after the object is clamped by the clamp part, a voltage is applied to the piezoelectric element to extend the extension part, and the clamping operation of the object by the clamp part is released, and then the piezoelectric element is released. Discharge the voltage to the device. By repeating this operation, the object is moved relative to the structure. During this time, the direction of the clamp portion with respect to the extension portion is changed by the variable joint according to the shape of the object.

According to the second aspect of the invention, after the object is clamped by the clamp part, a voltage is applied to the piezoelectric element to extend the extension part, and the clamping operation of the object by the clamp part is released, and then the piezoelectric element is released. Discharge the voltage to the device. The electric charge at the time of discharging is stored in the power storage element and is effectively used thereafter.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a view showing a first embodiment of an inchworm according to the present invention, and is a view showing an example similar to the transfer inchworm mechanism shown in FIG.

In FIG. 1, the magnetic material shaft 34 is fitted in the guide hole portion 35 of the external structure 30,
The shape of the shaft 34 is not uniform, and undulation is generated for some reason.

The side wall 36a of the recess 36 of the external structure 30,
Two sets of electromagnetic piezoelectric inchworms 39a and 39b are attached to 36b. Inchworm 39a,
39b is a laminated piezoelectric element (extension part) 32a, 32b,
Electromagnet (clamp part) 3 consisting of coil 29 and yoke 28
1a and 31b, and laminated piezoelectric elements 32a and 32b
Between the electromagnets 31a and 31b are spherical elements 37a and 37b, which are preferably made of a high-rigidity material. Further, elastic body elements 38a and 38b are arranged so as to embed and surround the spherical body elements 37a and 37b.
The variable joint is constituted by 37b and the elastic body elements 38a, 38b. The elastic elements 38a and 38b are drawn as a structure in which silicone rubber is adhered in this example.

In addition to this, a general mechanical element such as a leaf spring or a coil spring may be mechanically fixed between the electromagnets 31a and 31b and the laminated piezoelectric elements 32a and 32b. Further, the end portion 40 of the yoke 28 of the electromagnets 31a and 31b on the shaft 34 side is processed into a convex curved surface.

An outline of the mechanism for moving the magnetic shaft 34 in FIG. 1 is as follows. First, the coil 29 of the electromagnet 31a of the electromagnetic piezoelectric inchworm 39a on the left side of FIG.
A current is applied to the yoke 28 to attract the yoke 28 to the magnetic shaft 34. In this case, as shown in FIG.
When the yoke 28 comes into contact with the undulations of No. 4, the yoke 28 changes its posture and position along the undulations of the magnetic shaft 34 with the spherical element 37a as a fulcrum. Due to the relative displacement of the electromagnet 31a and the laminated piezoelectric element 32a caused by the displacement of the yoke 28, the elastic element 38a for adhering the electromagnet 31a and the laminated piezoelectric element 32a elastically deforms, and the elastic force and the attraction of the electromagnet 31a. Yoke 2 of this electromagnet 31a by force
8 and the magnetic body shaft 34 are integrally fixed.

In this case, since the end portion 40 of the yoke 28 of the electromagnet 31a is formed in a convex curved surface shape, the magnetic material shaft 34 moves to the yoke 28 more than when the yoke end portion 40 has an edge shape. The inconvenient rotational force applied can be reduced, which improves the efficiency of the attraction action of the electromagnet 31a. Actually, a gap is always formed between the magnetic body shaft 34 and the yoke 28 of the electromagnet 31a, but this is a very small gap, which is a wedge shape generated when the yoke 40 end 40 is edge-shaped. Compared to the gap, the adverse effect on the magnetic circuit is smaller. This is because the magnetic effect is proportional to the square of the gap length.

The rotational force acting on the yoke 28 from the magnetic shaft 34 can also be applied in the axial direction of the laminated piezoelectric element 32a via the elastic element 38a.
The piezoelectric element can be prevented from being damaged by greatly reducing the external force in the shearing direction to the laminated piezoelectric element 32a.

In this way, the electromagnet 31a and the magnetic material shaft 3 are
4 is magnetically attracted and fixed, and then the laminated piezoelectric element 32a
When a voltage is applied to the magnetic material shaft 34 and the magnetic material shaft 34 is extended along the magnetic material shaft 34, the magnetic material shaft 34 is moved to the right in FIG.

Next, the electric current applied to the coil 29 of the electromagnet 31a is removed, and then the laminated piezoelectric element 32a.
Electropiezoelectric inchworm 39
a returns to the initial state. At this time, the yoke 28 of the electromagnet 31a
Also returns to its original state by the restoring force of the elastic element 38a. Then, the attraction by the electromagnet 31a and the laminated piezoelectric element 3 are performed.
By repeating the process of extending 2a, the magnetic shaft 34 is continuously transferred to the right in FIG. In this case, even if the magnetic body shaft 34 has an indefinite shape such as waviness, the elastic body element 38a prevents the electromagnet 3 from moving.
It is possible to maintain the close contact state between the yoke 28 and the magnetic material shaft 34 during the operation of 1a, whereby the magnetic material shaft can be efficiently transferred.

The load acting from the outside on the magnetic shaft 34 is the elastic element 38a and the electromagnet 31a and the laminated piezoelectric element 3.
The magnetic shaft 34 can be moved to the left in FIG. 1 by reversing the phases of the attraction by the electromagnet 31a and the extension of the laminated piezoelectric element 32a under a condition smaller than the force for joining 2a.

In this embodiment, the electromagnetic piezoelectric inchworm 39a is used.
In addition, another electromagnetic piezoelectric inchworm 39b is provided. By driving this electromagnetic piezoelectric inchworm 39b in the same manner as the above-mentioned inchworm 39a, the magnetic shaft 34 can be continuously transferred in the left direction in FIG. Therefore, these electromagnetic piezoelectric inchworms 3
By appropriately selecting the driving states of 9a and 39b,
The magnetic shaft 34 can be freely moved in the left-right direction in FIG.

2A and 2B show the second embodiment of the present invention. In FIG. 1, the yoke and the laminated piezoelectric element that form the electromagnetic piezoelectric inchworm relatively change with respect to the posture and the position. However, in the second embodiment shown in FIGS. 2A and 2B, the posture variation mainly occurs. Shows the case with.

2 (a) and 2 (b), the description will focus on the parts different from those of the first embodiment shown in FIG. 1, and the same parts are designated by the same reference numerals and detailed description thereof will be omitted. Figure 2
As shown in (a), a conical or hemispherical pivot 41 is fixed to the laminated piezoelectric element 32a, and the pivot 41 is rotatably fitted in the recess 42 of the yoke 28 of the electromagnet 31a. Further, the yoke 28 of the electromagnet 31a and the laminated piezoelectric element 32a are bonded by the elastic element 38a as in the case of FIG.

In FIG. 2B, instead of the pivot, the spherical element 47 is rotatably fitted between the recess 44 on the yoke 28 side and the recess 43 on the piezoelectric element 32a side, and laminated with the yoke 28. The piezoelectric element 32a is adhered by an elastic element 38a.

In the structure shown in FIGS. 2A and 2B, the external force in the shearing direction of the laminated voltage element 32a due to the shape change of the magnetic material shaft 34 (FIG. 1) to be transferred is
The force in the axial direction of the laminated piezoelectric element 32a can be changed via the elastic element 38a, and damage to the piezoelectric element 32a can be avoided. In addition, the pivot 4 shown in FIGS.
If the fitting state of 1 or the spherical element 47 is made relatively gradual, the adaptability to the position fluctuation can be secured to some extent. In this case, the convex portion (pivot 41
Or spherical elements 47) and recesses (cavities 42, 43, 44)
Since and also have the function of a stopper, it is possible to prevent an excessive relative position change between the electromagnet 31a and the piezoelectric element 32a. Figure 2
Also in the embodiment shown in (a) and (b), since the yoke end portion 40 (the portion in contact with the magnetic body shaft 34) of the electromagnet 31a is formed into a convex curved surface shape, it is different from the first embodiment shown in FIG. Similarly, the attractive force of the electromagnet 31a can be efficiently used.

FIG. 3 shows a third embodiment of the present invention. Figure 3
1 is a part of the external structure 30 of the first embodiment shown in FIG. 1 extracted and described only for storing the electromagnetic piezoelectric inchworms 39a, 39b, and is the same as the first embodiment shown in FIG. The same reference numerals are given to the parts, and detailed description will be omitted. In FIG. 3, the external structure 30 to the support 5
1, the eddy current displacement gauge 52a,
52b is fixed.

The displacement meters 52a and 52b can measure the amount of expansion of the respective electromagnetic piezoelectric inchworms 39a and 39b, and the magnetic shaft 34 (FIG. 1) and the yoke 28 of these electromagnetic piezoelectric inchworms 39a and 39b. If there is no slippage between and, the amount of movement of the magnetic body shaft 34 can be known. Also, either the left or right electromagnetic piezoelectric inchworm 39a, 3
9b is activated, or the operation mechanism of the electromagnetic piezoelectric inchworms 39a, 39b according to the present invention (electromagnets 31a, 31b).
clamp operation by b and laminated piezoelectric elements 32a, 32b
It is possible to measure the direction in which the magnetic body shaft 34 moves by taking into consideration the combination of the extension operations of. As described above, the electromagnets 31a and 31b and the laminated piezoelectric element 32
The relative positions and orientations of a and 32b are the same as those of the spherical element 38a,
38b (or pivot element) and elastic element 37a, 3
7b, but an eddy current type displacement meter can measure an average distance when there is an inclination or the like, so there is no problem if the coarse movement amount of the magnetic body shaft 34 is known. Of course, the same effect can be obtained by using a capacitance type instead of an eddy current type displacement gauge, and even with an optical type, a detector is arranged in the range of reflected light due to the tilt of the electromagnet. There is no problem if you leave it.

FIG. 4 shows a fourth embodiment of the present invention. Figure 4
In FIG. 1, the same parts as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted. Further, FIG. 4A shows an example of the present invention, and FIG. 4B shows a conventional example for comparison.

Conventionally, when the piezoelectric element 32a is driven, as shown in FIG.
1 to the control element 62. This control element 6
The cable 2 sends a switching signal to the switch element 64 through the cable 74 to bring the piezoelectric element 32a, the switch element 64 and the driver element 63 into a conductive state, and disconnects the discharge control element 65 from the piezoelectric element 32a. At the same time, the control element 62 sends a control signal to the driver element 63 through the cable 72, and the driver element 63 applies a voltage having a quantity and a pattern for driving the piezoelectric element 32a to the piezoelectric element 32a through the cable 75. Also, while the control element 62 sends a drive control signal to the driver element 63,
Since this control element 62 sends a stop signal to the discharge control element 65 via the cable 77, this discharge control element 6
The function of 5 is stopped.

In the above process, the electromagnet 31a attracts the magnetic material shaft 34 (FIG. 1), the piezoelectric element 32a to which a voltage is applied expands, and the magnetic material shaft 34 described above is expanded.
To move. Then, this time, the attracting state of the electromagnet 31a is released, the voltage applied to the piezoelectric element 32a is discharged, the length of the piezoelectric element 32a is returned to the original value, and the process of attraction and extension is performed again. During the above-described discharging process, the control element 62 sends a switching signal to the switch element 64, disconnects the driver element 63 and the piezoelectric element 32a, and brings the piezoelectric element 32a and the discharge control element 65 into a conductive state. The control element 62 also sends a signal through the cable 77 to activate the discharge control element 65 and then discharges the charge to ground through the cable 78. That is, as described above, conventionally, the electric charge used for extending the piezoelectric element 32a is not discharged to the ground and reused.

However, when the power source is a storage battery, efficient use of power is important. Therefore, in the present invention shown in FIG. 4A, the cable 81 is connected to the discharge control element 65 described above.
The electricity storage element 67 is connected via the
A regulation element 68, which regulates the power to a certain specification, is connected via a cable 82. Note that FIG.
In the case of the present invention shown in FIG. 4A, the same parts as those in the conventional example of FIG.

The output from the regulation element 68 is
An output command signal sent through the cable 84 supplies power from the cable 83 to a desired element as electric power satisfying a desired specification. As a supply destination, for example, re-application to a lighting element or a piezoelectric element can be considered.

[0037]

As described above, according to the first aspect of the present invention, the direction of the clamp portion with respect to the extension portion can be changed by the variable joint according to the shape of the object. An excessive external force is not applied to the piezoelectric element in the extension portion due to the change in shape. Therefore, it is possible to increase the degree of freedom in selecting the shape and motion of the object.

According to the second aspect of the present invention, the electric charge at the time of discharging the piezoelectric element can be stored in the electric storage element, and the electric charge stored in the electric storage element can be effectively used thereafter.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a first embodiment of an inchworm according to the present invention.

FIG. 2 is a schematic side view showing a second embodiment of the inchworm according to the present invention.

FIG. 3 is a schematic side view showing a third embodiment of the inchworm according to the present invention.

FIG. 4 is a view showing a fourth embodiment of the inchworm according to the present invention in comparison with a conventional example.

FIG. 5 is a side view showing a conventional inchworm.

FIG. 6 is a side view showing a conventional inchworm.

[Explanation of symbols]

 30 external structure 31a, 31b electromagnet 32a, 32b laminated piezoelectric element 34 magnetic material shaft 37a, 37b spherical element 38a, 38b elastic element 39a, 39b inchworm

Claims (2)

[Claims] 1. An extension part which is fixed to a structure and is composed of a laminated piezoelectric element, a clamp part which clamps an object movable relative to the structure with a convex curved surface, and the extension part. A variable joint having a spherical element or an elastic element that is provided between the clamp portion and the clamp portion and that allows the orientation of the clamp portion with respect to the extension portion to be variable, and an inch worm. 2. An extension part which is fixed to a structure and is composed of laminated piezoelectric elements, and a clamp part which clamps an object movable relative to the structure with a convex curved surface. An inchworm, wherein an electric storage element that stores electric charges discharged from the piezoelectric element is connected to the extension portion.