JPH04194406A - Actuator - Google Patents

Abstract

PURPOSE:To enlarge momentum of curved telescopic motion of an actuator top end by gradually changing from one end to the other end an outside diameter of a cylindrical elastic body provided with plural pressure chambers divided by partition walls. CONSTITUTION:Both ends of a conical elastic body 2 for forming an outside circumferential wall are constituted of a top end sealing part 3, a bottom sealing part 4 with inserted operating tubes 5a-5c and elastic partition walls 9, 10, 11 for dividing the inside into three pressure chambers. Accordingly, an outside diameter of the conical elastic body 2 is gradually decreased from the bottom sealing part 4 toward the top end sealing part 3 so that the elastic body is gradually changed from one end to the other end to enlarge a moving area of a top end of an actuator 1 and precise action control can be conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to an actuator, and particularly to an actuator that is operated by fluid energy and has a large momentum of bending and expansion/contraction at the tip of the actuator.

(Prior Art) Air-hydraulic cylinders, air-hydraulic motors, and the like have been widely used as actuators that operate using the energy of fluids such as air and oil.

Since these 7 cutuators generally have sliding parts such as pistons and cylinder caps, there are problems such as leakage of working fluid from these sliding parts and difficulty in smooth operation and precise positioning due to sliding friction of parts.

In contrast, an actuator has been proposed in which a working fluid is applied to a cylindrical elastic body having a pressure chamber formed therein to cause a predetermined deformation.

(Refer to Japanese Unexamined Patent Publication No. 1-247809).

Here, the structure of the actuator made of this cylindrical elastic body will be explained with reference to FIGS. 8(a) and 8(b-).

- The cylindrical elastic body 50 constituting the actuator is shown in FIG.
), an elastic main body 51 forming an outer peripheral wall;
Tip sealing parts 52 fixed to both ends of this elastic body 51
, a root sealing portion 53, and three operating tinibs 54g, 54b, and 54c fitted into the root sealing portion 53.

Among these, the elastic body main body 51 includes 3' unit cylindrical elastic bodies 55a each having the same fan-shaped cross section.

55b and 55c are integrally molded by adhering them in parallel in the axial direction. Note that the unit cylindrical elastic body 55
a, 55b, and 55c are made of silicone rubber, for example. For this reason, elastic partition walls 56° 57.58 are extended in the axial direction of the cylindrical elastic body by the bonded parts, and these elastic partition walls 56° 57.58 allow 3 parts inside the cylindrical elastic body.
A pressure chamber 59,60,61 of the chamber is formed.

Further, the unit cylindrical elastic bodies 55a and 55b.

Reinforcing fibers 62 are spirally wound around the outer periphery of the reinforcing fibers 62 at close intervals, and a silicone rubber coating 63 made of an elastic material is formed to cover the outer periphery. Therefore, the cylindrical elastic body 50 exhibits anisotropic elastic properties due to the combined effect of the reinforcing fibers 62 and silicone rubber, and the direction in which the longitudinal elastic modulus is small approximately coincides with the axial direction of the cylindrical elastic body 50. On the other hand, in the radial direction R perpendicular to the axial direction, the reinforcing fibers 62 restrain deformation, so the longitudinal elastic modulus increases, making it difficult to stretch.

Furthermore, the tip sealing portion 52 is formed of metal or the like,
The unit cylindrical elastic bodies 55a, 55b.

It has a fan shape so as to seal each pressure chamber 59, 60, 61 formed in 55c, and one end thereof is connected to the unit cylindrical elastic body 55.
a, 55b, and 55c.

Further, the root sealing part 53 also has a fan shape like the tip sealing part 52, and has one end connected to the unit cylindrical elastic bodies 55a, 55b, and 55.
5c is inserted and fixed.

Furthermore, a mounting hole 5 for connecting the operation tube 54
3a, 53b and 53c are bored corresponding to each pressure chamber 59°60.61. The operation tube has mounting holes 53a and 53b formed with adhesive or the like.

53c, and the other end is connected to a control unit and a pressure source (not shown). The control section is capable of freely adjusting the pressure of the working fluid sent to each pressure chamber.

Next, the operation of this cylindrical elastic body 50 will be explained with reference to FIG. 8(b).

First, a working fluid is sent from a pressure source (not shown) to the pressure chamber 59 through the operation tube 54a to increase the internal pressure.

At this time, as shown in FIG. 8(b), the pressure chamber 59
extends in the axial direction, and the cylindrical elastic body 50 is curved in the entry direction to be in the state shown by the broken line. In this state, if the pressure in the pressure chamber 61 is further increased via the operation tube 54c, the cylindrical elastic body 50 can be further curved in the B direction.

By changing the combination of pressures applied to the three pressure chambers 59, 60, 61 in this way, the cylindrical elastic body 5
0 can be curved in any direction. Furthermore, by increasing the pressures in the three pressure chambers equally, the cylindrical elastic body 50 can be stretched straight in the axial direction.

In this way, by controlling the pressures in the three pressure chambers using the characteristics of the anisotropic elastic material, the cylindrical elastic body can simultaneously bend and expand/contract.

Therefore, by using this cylindrical elastic body, an actuator with a small diameter and compact structure can be realized, and this actuator enables smooth operation without leakage of working fluid compared to conventional air-hydraulic cylinders. .

(Problem to be solved by the invention) ゛However,
In the above-mentioned actuator, the outer diameter of the cylindrical elastic body and the elastic modulus of the elastic material constituting the cylindrical elastic body are made to be constant throughout, and from one end of the cylindrical elastic body to the other end. It curves with the same curvature throughout. Therefore, there is a problem that the movable range at the tip of the actuator is limited, making it difficult to operate over a wide range.

Furthermore, if the tip of the actuator comes into contact with an object and a load is applied, the deformation of the base becomes large, which may make it difficult to control the attitude of the actuator.

On the other hand, as mentioned above, since this actuator has a small diameter and a compact structure, there is a demand for its application to devices that require minute movements at the tip of the device, such as micromanipulators. To this end, it is necessary to increase the momentum of the actuator's tip for bending and expanding, and to provide an actuator that has a tip that is highly sensitive to operation commands.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an actuator having a structure that eliminates the problems of the above-mentioned conventional techniques and allows the momentum of the bending, expansion and contraction of the tip of the actuator to be increased with the same operation as in the prior art.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention adjusts the pressure in each pressure chamber of a cylindrical elastic body whose interior is divided into a plurality of pressure chambers by an extended partition wall. The actuator is characterized in that the outer diameter of the cylindrical elastic body is gradually changed from one end to the other, and the inside of the cylindrical elastic body is divided into a plurality of pressure chambers by an extended partition wall. In the actuator that operates by adjusting the pressure in each pressure chamber,
It is characterized in that the elastic modulus of the cylindrical elastic body is gradually changed from one end to the other end.

(Function) According to the present invention, since the outer diameter of the cylindrical elastic body of the actuator is gradually changed from one end to the other end, the elastic modulus of the cylindrical elastic body of the actuator is also gradually changed from one end to the other end. Therefore, when the pressure in each pressure chamber of the cylindrical elastic body is adjusted and operated, the curvature and elongation increase from the base to the tip, making it possible to widen the operating range of the actuator tip and also enable fine control of movement. becomes.

(Embodiment) An embodiment of the actuator according to the present invention will be described below with reference to FIGS. 1 to 4.

1st v! J indicates an actuator 1 according to the present invention, and this actuator 1 has a conical elastic body 2 forming an outer peripheral wall and a conical elastic body 2 at both ends, similar to the conventional actuator shown in FIG. 8(a). Fixed tip sealing part 3
, a base sealing part 4, and three operating chinives 5a, 5b, and 5c fitted into the base sealing part 4. As shown in the figure, the conical elastic body 2 has an outer diameter that gradually changes from the base to the tip, and a small cap-shaped tip sealing part 3 is fixed to the tip. .

Further, as shown in FIG. 3, this conical elastic body 2 is composed of three unit elastic bodies 7 whose cross-sectional shape is fan-shaped, which is a circle divided into three equal parts, and whose cross-sectional area gradually decreases from the base to the tip.
a, 7b, and 7c, and an elastic partition wall 9 formed inside. 10° 11 creates 3 pressure chambers 12.1
It is divided into 3.1-4. This pressure chamber 12.13.
14 also has a fan shape with a cross-sectional area divided into three equal parts, and as mentioned above, the cross-sectional area gradually decreases from the base to the tip.

Here, the manufacturing procedure of the conical elastic body 2 will be explained.

First, a core having an outer surface approximately the same shape as the inner surface of the pressure chamber is prepared. Using this core as a core, an elastic member that will become the unit elastic member 7 described above is molded from silicone rubber. Then, reinforcing fibers 15 are spirally wound around the outer circumferential surface of this elastic member made of silicone rubber so as to be closely spaced, thereby producing a unit elastic body 7 having a shape in which a truncated cone is divided into three parts in the axial direction.

Next, a truncated conical elastic body 2 is manufactured using the three unit elastic bodies 7a, 7b, and 7c. First, conical elastic body 2
A female mold having an inner surface shape that is almost the same as the outer shape is prepared. Then, the three unit elastic bodies 7a, 7b, 7c are inserted into the female mold in a truncated cone shape, and silicone rubber is filled between the unit elastic bodies 7a, 7b, 7c.
and form a peripheral coating on the outer peripheral surface to form a unit elastic body 7a.
.

7b and 7c are integrated to form the conical elastic body 2.

Note that the conical elastic body 2 is a unit elastic body 7a.

The reinforcing fibers 15 were wound around 7b and 7c, and then they were integrated and fixed, but three elastic members without the reinforcing fibers wound around them were fixed to form a truncated cone shape, and then the reinforcing fibers were wound around the outer peripheral surface. It may also be manufactured by turning it and covering its surface with a silicone rubber film.

In this case as well, the conical elastic body 2 exhibits anisotropic elastic properties due to the combined action of the reinforcing fibers and silicone rubber, and the direction of the smaller elastic modulus approximately coincides with the axial direction of the conical elastic body 2. On the other hand, since the reinforcing fibers 17 restrain deformation in the radial direction R perpendicular to the axial direction, the elastic modulus increases, making it difficult to stretch.

Further, the root sealing portion 4 has a cylindrical shape with a fan-shaped cross section, and one end thereof is fitted and fixed to the unit elastic bodies 7a, 7b, and 7c. Furthermore, this root sealing part 4 has the above-mentioned operating chinibu 5.
Mounting holes 4a, 4b, 4c for connecting each pressure chamber 1
It is drilled in accordance with 2.13.14. The operation tube 5 is hermetically fixed to the mounting holes 4a, 4b, and 4c with adhesive or the like, and the other end is connected to a control section and a pressure source (not shown). The control section is capable of freely adjusting the pressure of the working fluid, such as air or water, sent to each pressure chamber.

Therefore, since the present actuator 1 has the above-described structure, the weight of the tip can be reduced, and a large movable range can be ensured.

The operation of the conical elastic body 2 of the uni-lever will be explained with reference to FIG.

First, a working fluid is sent from a pressure source (not shown) to the pressure chamber 12 through the operation tube 5a to increase the internal pressure. At this time, as shown in FIG. 2, the pressure chamber 12 extends in the axial direction, and the conical elastic body 2 curves in the direction A, as shown by the broken line.

In this curved state, the radius of curvature decreases from the base to the tip, and in the maximum curved state, the tip can face toward the rear base. In this state, if the pressure in the pressure chamber 14 is further increased via the operation tube 5C, the conical elastic body 2 can be further curved in the B direction. By changing the combination of pressures applied to the three pressure chambers 12, 13, 14 in this way, the conical elastic body 2 can be curved in any direction. Moreover, if the pressures in the three pressure chambers are equally increased, the conical elastic body 2 can be straightened in the axial direction.

In this way, by controlling the pressure in the three pressure chambers using the properties of the anisotropic elastic material, the conical elastic body can simultaneously perform a wide range of bending and expansion/contraction operations at its tip. By applying it to an endoscope, etc., and attaching a camera to the tip, a wide range of inspections can be performed.

It is also possible to grip an object by wrapping the actuator body around the object.

Next, as a modification of the above embodiment, an actuator in which the rigidity of the tip is further reduced and the flexibility is increased will be explained with reference to FIG.

FIG. 4(a) shows a longitudinal section of the conical elastic body 2 of the above embodiment, and the thickness of the outer peripheral wall is constant.

On the other hand, FIG. 6(b) shows an example in which the thickness of the outer peripheral wall is reduced toward the tip. In an actuator with such a structure, the bending rigidity or axial rigidity of the tip can be reduced by 1 more than that shown in Figure (a). Suitable for cases where soft movements are required, such as when wearing a As a method of manufacturing this actuator, the shapes of the core and female mold described above may be set so that the thickness thereof shows a predetermined change.

Same again! 11(c) is a thin wall portion 1 on the inner peripheral wall at a predetermined pitch.
6 was formed. This actuator has annular protrusions formed at a predetermined pitch on the surface of a core, and a conical elastic body 2 formed on the outer periphery of the annular protrusions. According to this actuator, the thin portion 16 of the conical elastic body 2 is curved with a large curvature, and the entire conical elastic body 2 is bent to have a polygonal shape rather than a circular arc shape.

Therefore, a wide range of curvature and expansion/contraction can be realized at the tip without substantially reducing the stiffness of the entire actuator.

Next, as another invention, the fifth invention concerns an actuator in which the elastic modulus of the elastic material constituting the cylindrical elastic body is gradually changed from one end of the actuator to the other end.
This will be explained with reference to FIGS. 7 to 7.

Fig. 5 shows an actuator in which a pressure chamber inside the cylindrical elastic body is fabricated by joining a plurality of short cylindrical elastic bodies 20, 20... in the axial direction. 21 is set so that the elastic modulus decreases from the base to the tip.

That is, the elastic modulus E1 of the base 21a is
Letting the elastic modulus En of 1b be El > En.

FIG. 6 shows an exploded view of this actuator. Its structure is almost the same as the conventional actuator made of a cylindrical elastic body shown in FIG. It is attached.

The cylindrical elastic body 21 according to the present invention may be made of a single elastic material such as silicone rubber, or may be made of a combination of other elastic materials. Its production consists of individual short cylindrical elastic bodies 20.20...
- are joined in the axial direction to produce a cylindrical elastic body 21 of a predetermined length, and then the tip sealing part 52, the root sealing part 53, and the 3
This can be done by attaching the operating tubes 55a, 55b, and 55c.

For example, when the cylindrical elastic body 21 is manufactured from a single material such as silicone rubber, the elastic modulus can be changed by appropriately changing the heating conditions and catalyst conditions during material manufacture.

On the other hand, in order to reduce the deformation occurring at the base, a cylindrical elastic body made of a composite material may be manufactured using different materials with high elastic modulus. For example, if a metal tube made of aluminum or the like is used as the dissimilar material, deformation at that portion can be restrained and the structure of the actuator can be reinforced. Other materials that can be used include engineering plastics and hard rubber. In addition, when these materials are used, it is preferable to have a highly airtight joint structure to prevent leakage of working fluid from the joint, and for this purpose it is also possible to change the cross-sectional shape of each pressure chamber. .

Note that FIG. 7(a) shows an example of joining the cylindrical elastic body 21, but if it is difficult to set the elastic modulus finely, as shown in FIG. 7(b), It is also possible to change the wall thickness of the cylindrical elastic body 21 while changing the elastic modulus. As a result, even when the elastic modulus is constant, the cross-sectional area and the second moment of inertia of the cylindrical elastic body 21 can be made small, and the bending/expanding state of the actuator can be set by delicately changing.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, since the outer diameter of the cylindrical elastic body of the actuator is gradually changed from one end to the other, the elastic modulus of the cylindrical elastic body of the actuator is changed from one end to the other. Since it is gradually changed toward the end, it is possible to widen the operating range of the tip of the actuator, and also to perform fine control of the operation, which has the effect that the actuator can be applied to a wide range of applications.

[Brief explanation of the drawing]

1 and 2 are perspective views showing one embodiment of the actuator according to the present invention, FIG. 3 is a cross-sectional view of the same, and FIGS. 4 and 7 are modifications of the outer circumferential wall of the cylindrical elastic body. longitudinal section,
5 and 6 are perspective views showing one embodiment of an actuator according to another invention, and FIG. 8 is a perspective view showing an example of an actuator made of a conventional cylindrical elastic body. 1...Actuator, 2...Conical elastic body, 12
．． 13.14...pressure chamber, 2o...short cylindrical elastic body,
21...Tubular elastic body. Applicant's agent Sato-Yu #, f a Cram school 2 Iro 3 Figure (a) Figure 7

Claims (1)

[Scope of Claims] 1. In an actuator that operates by adjusting the pressure in each pressure chamber of a cylindrical elastic body whose interior is divided into a plurality of pressure chambers by an extended partition wall, the outside of the cylindrical elastic body is An actuator characterized by having a diameter that gradually changes from one end to the other. 2. In an actuator that operates by adjusting the pressure in each pressure chamber of a cylindrical elastic body whose interior is divided into a plurality of pressure chambers by an extended partition wall, the elastic modulus of the cylindrical elastic body is changed from one end to the other. An actuator characterized in that the actuator is gradually changed over the period of time.