JPS61219592A - 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 that is applied to, for example, a robot hand and is made of a suitable shape memory alloy, a thermoelectric conversion element, and a mechanical spring and is operated by current control.

Conventionally, in order to construct a robot hand that grasps objects or locally displaces a mechanism, it is necessary to use a power source such as a motor powered by air pressure, hydraulic pressure, or electricity, and force such as a coil, wire, or gear. transmission mechanism is required. 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 this, 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.

An embodiment of the present invention will be described in detail below 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 nickel N1, T i -N around 50%
i alloy or Cu-Al1-Ni alloy, Cu-Zn-A
It is a characteristic that appears in alloy composition ranges called Cu-based / β-phase alloys such as L alloy and Cu-Zn-8i alloy, and once a predetermined shape is memorized in the matrix transformation temperature range, the temperature decreases below the martensitic transformation temperature. Even if it is deformed during the process, when the temperature is raised to a temperature higher than the martensitic transformation point, it exhibits a shape memory property in that it returns to the shape previously deformed during the matrix transformation. As for the force, the change in force for the same amount of strain at the martensitic transformation temperature and at the parent phase transformation temperature is more than four times that at the parent phase transformation than at the martensitic transformation.
When the martensitic transformation point is exceeded by increasing the temperature,
While returning to the memorized shape, a large mechanical force can be applied to the outside as the shape is displaced. Incidentally, in the Ti-Ni alloy system, the stress during martensitic transformation is 14 to 15 kg/mff1, but the stress during matrix transformation is approximately 60 k at the same amount of strain.
g/mrfl.

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 is one that exhibits the Peltier effect, which exhibits 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 B i, T e, (T e 8e) 3, and other alloys are used as materials.

Two thermoelectric conversion elements 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 the mechanical spring 3 is attached to the shape memory element 1 using screws 5. In addition, FIG. 6 shows the state of martensitic transformation of the shape memory element 1,
FIG. 7 shows the state of matrix transformation of the shape memory element 1, and shows how the shape memory element 1 deforms into the memorized shape against the mechanical spring 3 during matrix transformation. There is.

t1 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 structure 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. As shown in FIG. 9, a mechanical spring 3 is fixed by a screw 5 so as to be sandwiched between the upper and lower sides, and a thermoelectric conversion element 2 is provided 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 also provided to insulate the shape memory element 1. Therefore, when the shape memory element 1 that was at the time of martensitic transformation reaches the matrix transformation temperature by energizing the thermoelectric conversion element 2, the shape memory element 1 transforms into the first state.
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 4 inches or less, so a single mechanical actuator 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 6A.

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. Note that 7 indicates a connection arm and 8 indicates an arm.

FIGS. 15A and 15B show an example in which a manibulator for gripping a workpiece is constructed using three mechanical actuators as shown in the example in FIG. 114. In FIG. 1A, each mechanical actuator 10'/J' 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, but if current is applied to the thermoelectric conversion element 12 by operating the control unit 11, , when the shape memory element 14 is heated to reach the matrix transformation temperature, the workpiece 13 is forced to return to its already memorized shape against the force of the mechanical spring 15, as shown in FIG. You can pick it. 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. When the workpiece 13 is still to be released, by controlling the thermoelectric conversion element 12 to change the direction of current supply and to have a cooling effect, the matrix transformation temperature of the shape memory element 14 changes to the martensitic transformation temperature. As shown in FIG. 2, the workpiece 13 is returned to its original extended state, and the workpiece 13 can be separated.

Note that although the mechanical actuator shown in the example in FIG. 15 has two degrees of freedom for each arm, the shape may vary.

Of course, it is possible to increase the degree of freedom in deforming the memory element, and by arbitrarily selecting the direction of the degree of freedom, it is possible to construct a mechanical actuator or manipulator that performs complex operations.

Furthermore, in the above example, various actuators are constructed by combining mechanical actuators that generate one bending displacement. By arranging a conversion element and controlling partial heating and cooling, a mechanical actuator that does not perform more complicated operations can be obtained.

As described above, according to the present invention, both ends of the mechanical spring and the thermoelectric conversion element are respectively fixed to the side surface of the shape memory element along the axis of the shape memory element, and the shape memory element is aligned with the axis in advance during matrix transformation. Since the memory element is stored in such a way that it is twisted relative to the memory element, the time delay caused by the heat conduction of the heating means to the memory element is eliminated, compared to a conventional configuration in which the heating means is located remotely. Improved response characteristics
Further, due to the presence of the mechanical spring, the point of action during Martensi F transformation of the memory element can be stably reproduced, and the reliability of the actuator itself is increased. Furthermore, it does not generate the noise associated with the operation of mechanical actuators composed of conventional gears, shafts, valves, etc., the number of parts can be significantly reduced, and control can be easily performed. has.

[Brief explanation of drawings]

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, FIG. 6 is a front view showing another example of the present invention, FIG. 7 is a diagram also used to explain the operating state, and FIG. 8 is another example of the present invention. FIG. 9 is a side view, FIG. 10 is a plan view, FIG. 11 is a sectional view, FIGS. 12 and 13 are diagrams showing operating states, and FIG. 14 is a side view. B and C are diagrams for explaining the configuration and operation of a mechanical actuator to which the present invention is applied;
FIGS. 15A and 15B are diagrams for explaining the configuration and operation of an applied example of the present invention. 1... Shape memory element, 2... Thermoelectric conversion element, 3...
・Mechanical spring. Applicant's agent Patent attorney Takatoshi Akiyama lθ diagram. and 12th. Figure 75 Figure 74 [! ] Ku

Claims (1)

[Claims] Both ends of the mechanical spring and the thermoelectric conversion element are respectively fixed to the side surface of the shape memory element along the axis of the shape memory element, and the shape memory element is memorized in advance so as to be twisted with respect to the axis during matrix transformation. A mechanical actuator characterized by: