JPS58165989A - Machine actuator - 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 The present invention relates to a mechanical actuator comprising a shape memory alloy, a thermoelectric conversion element, and a mechanical spring, which is suitable for use in robots, etc., and is operated by controlling current.

Conventionally, to construct a robot hand that grasps objects or locally displaces a mechanism, a power source such as a motor powered by pneumatics, hydraulics, or electricity, and a force transmission mechanism such as pulp, wire, or gears are required. need. As a result, the overall structure tends to be large, noise is often generated, the usage environment is degraded, there are many failures, and there is a lack of reliability.

In view of these points, the main object of the present invention is to propose a mechanical actuator that simplifies the structure of this type of mechanical actuator, eliminates noise, and facilitates continuous control.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view showing an example of the present invention, FIG. 2 is a side view, FIG. 3 is a plan view, and FIG. 4 is a bottom view. 1 shows a shape memory element made of a shape memory alloy. The shape memory alloy is T i -N i near 50% nickel
alloy or Cu-Al-Ni alloy, Cu-Z n-A
1 alloy, Cu-Zn-8i alloy, etc., which appear in alloy composition ranges called Cu-base/β-phase alloys. Even if the material is deformed during the process, when the temperature is raised to a temperature above the martensitic transformation point, it exhibits a shape memory property in that it returns to the shape previously deformed during the matrix transformation. Moreover, the change in force for the same amount of strain at the martensitic transformation temperature and at the matrix transformation temperature is more than four times as large as at the matrix transformation than at the martensitic transformation. When the martensitic transformation point is exceeded, while the memorized shape is restored, a large mechanical force can be applied to the outside due to the displacement of the shape. Incidentally, in the Ti-Ni alloy system, the stress during martensitic transformation is 14 to 15 kg/-, but during matrix transformation, the stress is approximately 60 kg/- at the same amount of strain.
It can even reach mm.

As shown in FIGS. 1 and 2, the shape memory element 1 has a rectangular parallelepiped shape with male screws 1a formed at both ends, and four parts 1b for sandwiching the thermoelectric conversion element 2 are formed at the lower center part. At the bottom is a dovetail groove 1C into which the mechanical spring 3 is inserted.
was formed.

The thermoelectric conversion element 2 used is one that exhibits the Beltier effect, which shows a phenomenon in which by passing a direct current through the parts of joined dissimilar metals, a heating and cooling effect is produced in the joint depending on the type of joining metal and the direction of the current. , Zn5b, PbTe, u-type Bi2Te5(TeSe)3, and other alloys are used as materials.

Two thermoelectric conversion elements 2 are disposed at approximately the center of the shape memory element 1 with an electrical insulating layer 4 interposed therebetween so as to be perpendicular to the longitudinal direction of the shape memory element 1.

The shape memory element 1 is made to memorize its shape by applying the required bending deformation in advance as shown in FIG. 5 at the matrix transformation temperature, and is kept in the shape as shown in FIG. 1 below the martensitic transformation temperature. . In this case, the stress of the shape memory element 1 during martensitic state is smaller than the force of the mechanical spring 3, and the stress of the shape memory element 1 during matrix transformation is set to be larger than the force of the mechanical spring 3. Shape memory element 1
The heating and cooling of the shape memory element 1 is adjusted appropriately by the current flowing through the thermoelectric conversion element 2. For example, by applying a current to the thermoelectric conversion element 2, the temperature of the shape memory element 1 changes from martensitic transformation to matrix transformation. The stress of the memory element 1 prevails, and both ends of the shape memory element 1 form a constant angle, as shown in FIG.

Therefore, by controlling the current to the thermoelectric conversion element 2 and connecting other mechanisms to both ends of the shape memory element 1, it can be made to act as a mechanical actuator.

FIG. 6 is a diagram showing another example of the present invention. This example is the same as the example in FIG. 1, except that screws 5 are used to attach mechanical spring 3 to shape memory element 1. Note that FIG. 6 shows the state of martensitic transformation of the shape memory element 1, and FIG. 7 shows the state of matrix transformation of the shape memory element 1.
The shape memory element 1 is shown deforming into a memorized shape against the mechanical spring 3 during matrix transformation.

FIG. 8 is a diagram showing another example of the present invention, FIG. 9 is a side view, and FIG. 10 is a plan view. In this example,
At the time of matrix transformation of the shape memory element 1, as shown in FIG.
The configuration is such that the shape is memorized so that twisting occurs along the axis. The cross section of the shape memory element 1 is circular, and as shown in FIG. 9, mechanical springs 3 are fixed with screws 5 so as to be sandwiched between the upper and lower side surfaces, and thermoelectric conversion elements 2 are provided so as to be sandwiched between the left and right sides. As shown in FIG. 11, a gap is provided so that the thermoelectric conversion element 2 does not come into contact with the mechanical spring, and an insulating layer 4 is provided to insulate the shape memory element 1 as well. Therefore, when the matrix transformation temperature is reached by energizing the shape memory element 1Fi and the thermoelectric conversion element 2 that were at the time of martensitic transformation, the first
As shown in FIGS. 2 and 13, torsional displacement occurs against the force of the mechanical spring 3. Note that heating or cooling is performed depending on the direction in which the current is applied to the thermoelectric conversion element 2, so it goes without saying that the current direction should be confirmed in advance.

FIG. 14 shows an example in which two mechanical actuators 6 described above are connected. When repeatedly using the shape memory properties of shape memory alloys, it is necessary to suppress the amount of strain caused by displacement to 4q/) or less, so a mechanical actuator alone can achieve large displacements, although this varies depending on the length of the connected arm. In order to achieve this, it is necessary to connect multiple mechanical actuators vertically on the same axis so that displacements can be integrated to produce large displacements. In this example, the displacements of the shape memory elements 1 are all set in the same direction, and the first mechanical actuator 6A is activated and the second mechanical actuator 6B is not activated (see FIG. 14C). 2
mechanical actuator 5A.

6B (see FIG. 14C). Of course, the desired movement can be made possible by appropriately combining a mechanical actuator as shown in the example of FIG. 1 and a mechanical actuator as shown in the example of FIG. In addition, 71'i is a connecting arm, and 8 indicates an arm.

15A and 15B show an example in which a manipulator for grasping a workpiece is configured using three mechanical actuators as shown in the example in FIG. 14. In FIG. 1A, each mechanical actuator 10 is supported by a control section 11, and the thermoelectric conversion element 12 is controlled by a power supply device of the control section 11. 13 indicates a workpiece. The thermoelectric conversion element 12 is in contact with the shape memory element 14 so as to cover approximately the center thereof. At the martensitic transformation temperature of the shape memory element 14 of each mechanical actuator 10, the mechanical actuator 10 is in an extended state due to the force of the mechanical spring 15. When energized, the shape memory element 14 heats up and reaches the matrix transformation temperature, and as shown in FIG. The workpiece 13 can be picked up. The gripping force at this time is extremely strong, so it will not fall accidentally. Therefore, by moving the entire control section 11,
Robot handling becomes possible. Furthermore, when the workpiece 13 is released, the shape memory element 14 is controlled by changing the current direction to the thermoelectric conversion element 12 to cool the workpiece 13.
from the parent phase transformation temperature to the martensitic transformation temperature.

As shown in FIG. 15A, the original elongated state is restored, and the workpiece 13 can be separated.

Although the mechanical actuator shown in the example in Fig. 15 has six arms with two degrees of freedom, it is possible to increase the degree of freedom of deformation of the shape memory element, and it is possible to change the direction of the degrees of freedom. By making arbitrary selections, mechanical actuators or manipulators with complex operations can be constructed.

In addition, in the above example, various actuators were constructed by combining mechanical actuators based on one bending displacement. Arrange the elements,
By controlling partial heating and cooling, it is possible to obtain a mechanical actuator that performs more complex operations.

As described above, according to the present invention, a shape memory element made of a shape memory alloy, a thermoelectric conversion element exhibiting the Peltier effect,
Since it is composed of mechanical springs, it does not generate the noise associated with the operation of mechanical actuators made of conventional gears, shafts, pulp, etc., and the number of parts can be significantly reduced, making control easy. It has the effect that it can be used.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an example of the present invention, FIG. 2 is a side view, FIG. 3 is a top view, and FIG. 4 is a bottom view.
FIG. 5 is a diagram also used to explain the operating state, and FIG. 6 is a front view showing another example of the present invention. FIG. 7 is a diagram for explaining the operating state, FIG. 8 is a diagram showing still another example of the present invention, FIG. 9 is a side view, FIG. 10 is a plan view, and FIG. 11 is a cross-sectional view. Figure, 1st
Figures 2 and 13 are diagrams showing operating states, Figure 14A,
15B and 15C are diagrams for explaining the configuration and operation of a mechanical actuator to which the present invention is applied, and FIGS. 15A and 15B are diagrams for explaining the configuration and operation of an application example of the present invention. 1... Shape memory element, 2... Thermoelectric conversion element, 3...
- Mechanical springs, 6A, 6B...first and second mechanical actuators. Agent Anatomist Akiyama Takaatsu 3 Figure 754 Figure 10 Figure 12 Figure 13 Figure 14 Figure 1511 ＼

Claims (1)

[Scope of Claims] 1. A mechanical actuator comprising a shape memory element made of a shape memory alloy, a thermoelectric conversion element exhibiting the Peltier effect, and a mechanical spring. 2. The shape memory element is in contact with the thermoelectric conversion element and is heated and cooled by a current flowing through the thermoelectric conversion element, and when the shape memory element transforms to martensitic state, it is expanded or contracted by the mechanical spring to enter the matrix state. 2. The mechanical actuator according to claim 1, wherein the mechanical actuator is configured to contract or expand in response to the force of the spring. 3. The mechanical actuator according to claim 1 or 2, wherein one or more mechanical actuators are combined to produce displacement in multiple directions.