JP3392598B2 - Actuator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator driven by the pressure of a fluid enclosed in a pressure chamber.

[0002]

2. Description of the Related Art In recent years, there has been an increasing need for micromanipulators that perform work in narrow spaces that are out of reach of humans, such as inside complex machines and inside the body. Research on an actuator having a structure as shown in FIG. 7 which uses fiber reinforced rubber for use in such a manipulator is under way. The actuator 101 shown in FIG. 7 has three pressure chambers 102a, 102b, 1 inside the Y-shaped partition 104.
02c, each pressure chamber 102a, 102b, 10
The elastic deformation operation is performed by adjusting the internal pressure of 2c.

The actuator 101 has sealing terminals 110 and 111 at both ends, and the pressure chambers 102a, 102b and 102c are connected via one sealing terminal 110.
Are connected to one ends of the three tubes 112, and the other ends of the tubes 112 are connected to the pressure control device 116. Then, the actuator 101 and the tube 1
The actuator device 100 is configured by the pressure control device 116 and the pressure control device 116.

If such an actuator 101 has a cross-sectional shape that does not change in the longitudinal direction and is made of a uniform material, it can be molded by extrusion, which is advantageous in terms of cost and labor. However, when the actuator is made of a uniform material, it bends when pressed and expands in the radial direction at the same time, which is not preferable from the viewpoint of strength. Further, when the actuators are arranged in parallel and used, adjacent actuators interfere with each other and a desired operation cannot be performed.

Therefore, in order to suppress the bulging in the radial direction of the actuator, fiber reinforced in the circumferential direction to give anisotropy to solve the above problem. Specifically, FIG.
Further, as shown in FIG. 8, by embedding the reinforcing fiber 108 at the position of the central portion 105a of the outer wall 105, anisotropy was provided.

[0006]

As described above, since the conventional actuator is always made of two or more kinds of materials in order to impart anisotropy, the number of manufacturing steps is increased and the cost is increased. There was a problem.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an actuator which is inexpensive in manufacturing cost and can suppress radial bulging during operation as much as possible. .

[0008]

According to a first aspect of an actuator of the present invention, a substantially cylindrical outer wall portion, a partition wall portion formed inside the outer wall portion so as to extend in the axial direction, and the partition wall portion. And a plurality of pressure chambers surrounded by the outer wall portion and formed to extend in the axial direction, a wall thickness of at least one of the outer wall portion of the pressure chamber or the partition wall portion of the pressure chamber The actuator is characterized in that the cross section is changed.

A second aspect of the actuator according to the present invention is the actuator according to the first aspect, wherein the partition wall portion increases in thickness from the center of the actuator toward the outer wall portion, and the outer wall portion extends from the partition wall portion. It is characterized in that the cross-sectional shape is such that the wall thickness decreases with increasing distance.

According to a third aspect of the actuator of the present invention, in the actuator of the first aspect, the outer wall portion becomes thicker as the distance from the partition wall portion increases,
It is characterized in that the partition wall portion is formed in a cross-sectional shape such that the thickness of the central portion is thin.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an actuator according to the present invention will be described with reference to FIGS. FIG. 1 shows a cross sectional view of a first embodiment of an actuator according to the present invention. The actuator according to the first embodiment includes a partition wall 1, an outer wall 2, and pressure chambers 3a, 3b, 3c formed by the partition wall 1 and the outer wall.

The partition wall 1 has a Y-shaped cross-sectional shape, and this shape is configured to extend in the longitudinal direction (direction perpendicular to the paper surface). The outer wall 2 has a circular cross-sectional shape surrounding the partition wall 1, and this circular shape is configured to extend in the longitudinal direction. The partition wall 1 is configured so that the cross-sectional dimension (thickness) increases from the center toward the connecting portion 4 with the outer wall 2.

Further, the outer wall 2 has a cross-sectional dimension that becomes thinner as it goes away from the connecting portion with the partition wall 1.

The partition wall 1 and the outer wall 2 form three pressure chambers 3a, 3b, 3c. When the pressure of the fluid contained in the pressure chamber 3b is increased, the actuator bends in the direction of the arrow α shown in FIG.

It has been found from the research conducted by the present inventor that the outer wall 2 can be prevented from bulging outward as much as possible when the pressure of the fluid is increased by making the cross-sectional shape of the actuator as shown in FIG. It was

The actuator having the above-mentioned cross-sectional structure can be extruded and molded from one kind of material, and the manufacturing cost can be reduced as compared with the conventional case.

Next, FIG. 2 shows a cross section of a second embodiment of the actuator according to the present invention. The actuator of the second embodiment differs from the actuator of the first embodiment shown in FIG. 1 in that a notch 5 is provided in the region on the outer peripheral side of the connecting portion 4 between the partition wall 1 and the outer wall 2. Providing this notch 5 makes it easier to bend when the fluid in the pressure chamber is pressurized.

It goes without saying that the actuator of the second embodiment also has the same effect as the actuator of the first embodiment.

Next, FIG. 3 shows a cross section of a third embodiment of the actuator according to the present invention. The actuator of the third embodiment differs from the actuator of the first embodiment shown in FIG. 1 in cross-sectional shape. That is, in the actuator of the third embodiment, the outer wall 2 has a cross-sectional dimension that becomes thicker as it moves away from the partition wall 1, and the partition wall 1 has a cross-sectional dimension that decreases from the outer peripheral side of the actuator toward the center of the actuator. It is formed so that it becomes thicker as it gets closer to the center. Specifically, the outer wall 2 has a protrusion 6 formed inwardly at a substantially intermediate position between the partition walls 1, and the partition wall 1 is formed such that the central portion 1a thereof is thin. There is.

Even if such a sectional shape, that is, a shape in which the actuator easily expands and contracts in the axial direction (longitudinal direction) and is hard to deform in the radial direction, the same effect as that of the actuator of the first embodiment can be obtained. Was first revealed by the inventor's research.

Next, FIG. 4 shows a cross section of a fourth embodiment of the actuator according to the present invention. The actuator of this embodiment is the same as the actuator of the third embodiment shown in FIG. 3, except that a protrusion 7 is further provided outwardly at a substantially intermediate position between the partition walls 1 of the outer wall 2. Is.

It has been clarified for the first time by the research of the present inventor that the actuator having such a cross-sectional shape has the same effect as that of the actuator of the first embodiment.

Next, the deformation characteristics of the actuators of the first to fourth embodiments and the conventional actuator having the cross-sectional shape shown in FIG. 8 are shown in FIG. 5 (a). Figure 5 (a)
In FIG. 5, the horizontal axis represents the bending angle (see FIG. 5B) of the actuator during operation, and the vertical axis represents the diameter of the central portion of the actuator during operation (see FIG. 5B).

Characteristic graphs g _{1 to} g ₄ show the deformation characteristics of the actuators of the first to fourth embodiments, and a characteristic graph g ₅ shows the deformation characteristics of the conventional actuator having the cross-sectional shape shown in FIG. Shows. These characteristics have a length of 50 mm and a thickness (diameter when not operating) of 12 m.
With respect to the actuator of m, the relationship between the bending angle (bending angle) of the tip when one pressure chamber is pressurized and the thickness (diameter) at this time is obtained by using the finite element method.

In the conventional actuator in which the partition wall and the outer wall have uniform cross-sectional dimensions, the deformation in the thickness direction becomes larger than the bending due to the pressurization, which is not good in appearance and increases the tensile stress of the outer wall. Therefore, it is understood from the characteristic graph g ₅ shown in FIG. 5A that the pressure cannot be increased until a sufficient bending angle is obtained.

On the other hand, from the characteristic graphs g _{1 to} g ₄ shown in FIG. 5A, in the actuator in which the cross-sectional dimension of the outer wall or the partition wall changes, the expansion in the radial direction during operation is suppressed. I understand.

6 (a) and 6 (b) are vertical cross sections when the actuator of the second embodiment shown in FIG. 2 and the conventional actuator shown in FIG. 8 are bent by 60 degrees. The broken line shows the longitudinal section of the actuator when it is not curved. From FIG. 7 as well, it can be seen that the actuator of the second embodiment is suppressed in radial expansion compared to the conventional actuator.

[0028]

As described above, according to the present invention, the manufacturing cost is low and the radial bulge during operation can be suppressed as much as possible.

[Brief description of drawings]

1 is a cross-sectional view of a first embodiment of an actuator according to the present invention.

FIG. 2 is a cross sectional view of a second embodiment of an actuator according to the present invention.

FIG. 3 is a cross sectional view of a third embodiment of an actuator according to the present invention.

FIG. 4 is a cross sectional view of a fourth embodiment of an actuator according to the present invention.

FIG. 5 is an explanatory diagram illustrating an effect of the present invention.

FIG. 6 is a vertical cross-sectional view of an actuator according to the present invention and a conventional actuator during operation.

FIG. 7 is a perspective view showing a configuration of a conventional actuator.

FIG. 8 is a cross-sectional view of a conventional actuator.

[Explanation of symbols]

1 partition 1a Central part of partition wall 2 outer wall 3a, 3b, 3c Pressure chamber 4 Partition and outer wall connection 5 notches 6 protrusion 7 Projection 100 actuator device 101 actuator 102a, 102b, 102c Pressure chamber 104 partition wall 105 outer wall 105a Center of outer wall 108 Reinforcing fiber 110 sealed terminal 111 sealed terminal 112 tubes 116 Control device

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-165110 (JP, A) JP-A-5-508351 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F15B 15/10

Claims (2)

(57) [Claims] 1. A substantially cylindrical outer wall portion, a partition wall formed inside the outer wall portion so as to extend in the axial direction, and surrounded by the partition wall portion and the outer wall portion so as to extend in the axial direction. And a plurality of pressure chambers formed, the partition wall portion increases in thickness from the center of the actuator toward the outer wall portion, the outer wall portion in a cross-sectional shape such that the wall thickness decreases as it moves away from the partition wall portion. An actuator characterized by being configured. 2. A substantially cylindrical outer wall portion, a partition wall portion formed inside the outer wall portion so as to extend in the axial direction, and surrounded by the partition wall portion and the outer wall portion so as to extend in the axial direction. A plurality of pressure chambers formed, wherein the outer wall portion has a thickness that increases with increasing distance from the partition wall portion, and the partition wall portion is configured to have a cross-sectional shape such that the central portion has a thin wall thickness. Characteristic actuator.