JP2635896B2 - Variable shape actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber actuator capable of performing a flexible movement, and more particularly, a plate-like member can be held flexibly from the surroundings by connecting a plurality of rubber actuators having both ends held in a ring. Related to rubber actuators.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, when a mechanical shock is applied to a wafer, an internal defect is generated, which may affect its electrical characteristics. Further, particles necessarily generated by such mechanical shock may be larger than the fine circuit elements to be formed on the wafer, and thus hinder necessary fine circuit processing. For these reasons, mechanical shock should be eliminated as much as possible in semiconductor manufacturing. However, conventionally, a mechanical movement element in an actuator such as a motor or a piston mechanism generally has a rigid structure, and is configured to have a movement on the order of microns and positioning accuracy by the rigidity. If such a rigid motion element hits another member or the like while performing a predetermined motion, a mechanical impact will be generated. Hereinafter, this is called a hard movement. Therefore, when such a hard movement is used for the wafer transfer or the like in the semiconductor manufacturing process, extremely precise position control and speed control need to be performed to suppress the occurrence of mechanical shock.

On the other hand, as seen in current robot driving, an actuator used under the integrated control by a microprocessor using a developed visual and tactile sensor is not necessarily a rigid structure and has a high machining accuracy. Not only those having Rather, it is expected that the use of a flexible actuator capable of flexible movement under such general control will lead to the development of artificial fingers that can replace human fingers. Therefore, it is considered that such a flexible-moving actuator can realize a shock-free transport mechanism applicable to a semiconductor manufacturing process under much simpler control than a hard-moving actuator. Therefore, the following four types of flexible actuators to be applied to such applications are known.

[0004] First, a rubber tube 30 is covered with a reinforcing fiber 31 in a direction inclined with respect to the tube axis (FIG. 5 (a)). When the compressed air is sent into the rubber tube 30, the compressed air has a volume (πD2L) inside the tube.
/ 4, D is the tube inner diameter and L is the tube length). However, the reinforcing fibers 31 covering the tube 30 try to keep the tube surface area (πDL) constant. Therefore, if the tube diameter D increases and the tube length L decreases in inverse proportion thereto, the tube internal volume is a quadratic function of the tube diameter D, so that the tube internal volume increases while keeping the tube surface area constant. Will be.

Therefore, the rubber tube 30 contracts in the axial direction when it is pressurized (FIG. 5B). In the contracted state, the ratio between D and L is deviated from the ratio in the free state, so that the wall material of the rubber tube 30 is subjected to the ballistic stress. Therefore, when the pressure is released, the rubber tube 30 extends and returns to the free length. By fixing one end of the rubber tube 30, the other end is used as an actuator that changes its position. (See Fukuda and Hosame, Robotics and Mechatronics Lecture '89 (1-6), 138-139)

The second actuator divides the inside of the rubber tube into three chambers in the circumferential direction to form an aggregate of three pressure chambers that are long in the axial direction. By applying different pressures to the respective pressure chambers, It enables various flexible deformations such as bending, axial extension, and torsion around the axis. (Suzumori,
Transactions of the Japan Society of Mechanical Engineers, C Edition (Hei 1-10), 2547-2
(See 552)

The third actuator is a rubber tube 3
A reinforcing fiber (peripheral reinforcing fiber) 33 is densely wound around 2 and another reinforcing fiber (axial reinforcing fiber) 34 is joined along the axial direction (FIG. 6A). When the circumferential reinforcing fibers 33 are pressurized in the rubber tube, they have an effect of preventing the diameter of the rubber winding from expanding and expanding only in the axial direction. Since the expansion in the axial direction is also prevented at the portion where the shaft reinforcing fibers 34 are joined, when the actuator is pressurized, the portion without the shaft reinforcing fibers 34 expands, and as a result, the actuator is curved as a whole. (FIG. 6 (b)). When an actuator (FIG. 6C) in which the shaft reinforcing fibers 34 are joined with an inclination angle with respect to the axial direction is used, this actuator shows a twisting motion around the axis by pressurization. Further, if the inclination angle is changed depending on the location, an actuator that performs combined movement of bending and torsion is realized. (See Tanaka, Mechanical Design 36, 8 (1992-7), 32-39)

The fourth actuator is a double tube formed by joining a rubber tube as an outer tube and a hard inner tube which is not deformed by pressurization. The inner tube has a shape shown in FIG. In this example, two portions of the outer tube are formed in a V shape as shown in FIG. 7B. This actuator is
Due to the pressurization, only the central V-shaped portion expands, so that it exhibits an articulated movement. (See Tanaka, Mechanical Design 36, 8 (1992-7), 32-39)

[0009] These flexible actuators are
When applied to a wafer transfer device of a semiconductor manufacturing apparatus, it is expected that an excellent wafer transfer mechanism that does not cause the occurrence of internal defects or particles due to mechanical shock is realized.

[0010]

However, each of the above-mentioned flexible actuators has various problems. Since the first actuator can only perform the expansion and contraction operation by itself, a special device is required to perform minute and various deformation operations in the device. Second
Can perform various operations by itself, but it is not easy to manufacture a rubber tube divided into three in the circumferential direction, which is disadvantageous in cost. In particular, it is difficult to realize a small-diameter long one. Further, there is a drawback that compressed air of three types of pressure is required for use. Furthermore, an extremely complicated three-dimensional analysis is required to analyze the actual deformation behavior of the tube based on the shape of the three chambers and the supply pressure. Therefore,
For pipe design and drive pressure design, advanced analysis techniques using, for example, a finite element method are required.

The third and fourth actuators have been conceived to solve these problems. However, each of them has only one end fixed and uses the non-fixed end as an output end. Is considered. However, when this type of flexible actuator is used to drive a heavy object by cantilever support, it swings due to the inertia of the load and bends due to gravity, and as a result, required positional accuracy cannot be obtained. Further, since the third actuator has the cantilever, for example, in the third actuator, if the joining position of the shaft reinforcing fibers 34 is slightly displaced, the movement as the actuator faithfully reflects the displacement. The joining position of the fiber 34 must be strictly controlled.

If the both ends are fixed, it is considered that the swing due to the inertia of the load is almost eliminated, and the joining position of the shaft reinforcing fiber 34 in the third actuator is not necessarily required to be strict. Since there is a portion where the total length cannot be changed, the operation cannot be performed when both ends are fixed. Therefore, it is difficult to apply it to a field requiring high positional accuracy, such as a wafer transfer / positioning mechanism of a semiconductor manufacturing apparatus.

The present invention has been made to solve the above-mentioned problems of the prior art, and does not cause unnecessary vibration, and therefore can achieve high positional accuracy by flexible movement, and requires a complicated control mechanism. It is another object of the present invention to provide a flexible actuator suitable for application to a semiconductor manufacturing field.

[0014]

In order to solve the above-mentioned problems, a deformable actuator according to the present invention comprises a flexible tube, a circumferential reinforcing fiber tightly wound around the tube, and the tube. In a rubber actuator comprising an axial reinforcing fiber joined in a part of the axial length in the axial direction, both ends of the tube are fixed, and the tube has a plurality of locations where the axial reinforcing fiber is joined. The configuration is characterized in that there are locations. Alternatively, the configuration is such that a plurality of the variable shape actuators are arranged in a ring shape.

[0015]

In the variable shape actuator according to the present invention having the above-described structure, when air pressure is applied to the inside of the tube having both ends fixed, the tube is curved because it is partially restricted by the reinforcing fibers bonded to the tube. . When the applied pressure is released, the tube returns to a linear state. When such actuators are arranged in a ring shape and the pressure is transmitted to each unitary actuator when air pressure is applied from a common pressurizing port, each actuator bends and deforms in response to the pressure, and the central portion of the actuator is curved. Move towards the center. When the applied pressure is released, each single actuator returns to a linear state. With the above movement,
The holding and opening of the plate member placed in the ring can be made flexible.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a variable shape actuator embodying the present invention will be described below with reference to the drawings. FIG. 1 (a)
FIG. 2 is a configuration diagram of the variable shape actuator of the present embodiment.
The actuator 1 shown in FIG. 1A is obtained by joining reinforcing fibers to a flexible tube 2 with an adhesive. There are two types of such reinforcing fibers, those that are perpendicular to the axial direction of the tube 2 and those that are parallel to the axial direction. The circumferential reinforcing fibers 3 perpendicular to the axial direction are tightly wound around the entire length of the tube 2 and have a function of restricting the radial expansion and contraction of the tube 2.

An axial reinforcing fiber 4 and an axial reinforcing fiber 5 are joined along the axial direction of the tube 2 at positions near both ends of the tube 2 and on an extension of each other. The shaft-reinforcing fibers 4 and the shaft-reinforcing fibers 5 have a function of restricting the elongation and shrinkage of the tube 2 in the axial direction at the position where they are joined. It has a function of restricting bending in a direction perpendicular to the direction.

The actuator 1 has both ends fixedly attached to a tube holder 6 and a tube holder 7, and is connected to a compressed air cylinder 9 via a pressure hose 8. The shutoff valve 10 interrupts the supply of the compressed air from the compressed air cylinder 9 to the actuator 1, and the release valve 11 releases the compressed air supplied to the actuator 1 to the atmosphere to return the actuator 1 to a natural state. Things. The actuator 1 having the above configuration has a linear shape as shown in FIG. 1A when in a natural state, that is, when the inside of the tube 2 is at atmospheric pressure. Then, the opening valve 11 is closed and the shutoff valve 1 is closed.
When 0 is opened, compressed air is supplied from the compressed air cylinder 9 and the inside of the tube 2 becomes high pressure.

At this time, the flexible tube 2 tends to expand as a whole. However, since the expansion is regulated by the reinforcing fibers connected to each other and the both ends are fixed, a unique movement is caused. Show. That is, since the elongation in the radial direction is regulated by the circumferential reinforcing fibers 3 wound over the entire length, the tube 2 mainly tends to elongate in the axial direction. However, the axial reinforcement is partially restricted by the axial reinforcing fibers 4 and the axial reinforcing fibers 5.

Here, the tube 2 will be considered by dividing into sections depending on whether the shaft reinforcing fiber 4 or the shaft reinforcing fiber 5 is joined. That is, in FIG. 1A, a section where the shaft reinforcing fiber 4 is bonded is referred to as section A, a section where neither the center shaft reinforcing fiber 4 and the shaft reinforcing fiber 5 are bonded is referred to as section B, The section where the reinforcing fibers 5 are joined is referred to as section C. In the section A and the section C, the side where the shaft reinforcing fiber 4 or the shaft reinforcing fiber 5 is bonded (FIG.
Only in (a) the middle upper part, the extension in the axial direction is restricted, and in the opposite side (the lower part in the middle in FIG. 1A), the extension in the axial direction is not restricted. Therefore, in these sections, the tube 2 tends to bend with the upper side in the figure inside. Since both ends are fixed, the vicinity of the center of the tube 2 moves upward in the figure. In the section B, the extension in the axial direction is not restricted on any side, so that the section B is deformed in accordance with the curvature of the section A and the section C. As a result, the actuator 1 when a high voltage is applied is in a state shown in FIG.

When the shut-off valve 10 is closed and the open valve 11 is opened, the high pressure inside the tube 2 is released to atmospheric pressure, so that the actuator 1 returns to the linear shape in FIG. The movement of the actuator 1 described here is due to the expansion and contraction of the flexible tube 2 by air pressure.
It is not rigid and does not give any impact if it hits another object during the movement. From the above, it can be understood that in the present embodiment, an actuator whose central portion shows a soft movement in the vertical direction is realized by pressurization and release to the atmosphere.

The present embodiment has various advantages because the both ends of the actuator are fixed. First, it is mentioned that excessive vibration does not occur, and then, even if the joining position of the shaft reinforcing fiber is slightly shifted, the movement as an actuator is not greatly affected. Further, another actuator 1 can be arranged at the end of the tube holder 6 in FIG. 1 and can be operated simultaneously. At this time, it can be said that the actuator 1 has both the function as an actuator and the function as a pipe.

In the above actuator 1,
The material of the tube 2 may be, for example, silicone rubber, raw rubber, or the like, but is not limited thereto, and may be any material having appropriate flexibility and elasticity. The material of the circumferential reinforcing fiber 3, the shaft reinforcing fiber 4, and the shaft reinforcing fiber 5 is as follows.
In addition to metal and carbon fiber, silk thread may be used.
A material having good compatibility with the adhesive and having high flexibility only in the operation direction and low flexibility in the non-operation direction should be selected. It is preferable to use the same adhesive as the tube 2 as an adhesive for joining them.

Next, a wafer holding apparatus according to a second embodiment of the present invention will be described with reference to FIG.
The wafer holding device 12 shown in a top view in FIG. 2A includes the actuator 1 according to the above-described first embodiment mounted on the tube holders 15 arranged at the four corners of the frame plate 13 having the hole 14 formed in the center. Are arranged in a square shape. In this wafer holding device 12, 4
Each of the tube holders 15
The pressure is supplied from a common pressure supply port 16 formed in the tube holder 15 at the upper right in the figure.

At the end of the common pressure supply port 16, as in the above-described example,
A compressed air cylinder, a shut-off valve, and an opening valve (not shown) are connected so that compressed air can be supplied and released to the atmospheric pressure. Each actuator 1 in the wafer holding device 12 is arranged such that the side to which the axis reinforcing fibers (4 and 5) are joined is located inside the square, and the center of each actuator 1 is
A wafer clip 17 is attached. FIG. 2B is a side view of the wafer holding device 12. The entire wafer holding device 12 is moved between a wafer take-out portion of a semiconductor manufacturing device and a wafer receiving portion of another semiconductor manufacturing device by an inter-device transfer device (not shown).

In the wafer holding device 12, when no compressed air is supplied, all the actuators 1 are at the atmospheric pressure, so that the wafer holding device 12 is in a linear state as described above. FIG.
(A) shows this state. Therefore, in this state, the wafer holding device 12 does not hold the wafer 18 because the wafer clips 17 do not contact the wafer 18.
FIG. 3A shows a cross-sectional view taken along the line EF in this state.

When the compressed air is supplied, each actuator 1 is brought into a high pressure state and deformed as shown in FIG. In the wafer holding device 12, since the axial reinforcing fibers (4 and 5) are disposed so as to be located inside the square as described above, each actuator 1
Curves inward. FIG. 4 shows a top view at this time. Therefore, at this time, each wafer clip 17 comes into contact with the wafer 18 and the wafer holding device 12 holds the wafer 18. FIG. 3 is a GH sectional view in this state.
(B).

The movement of each actuator 1 at this time is a flexible movement as described above. Therefore, the initial position of the wafer 18 is slightly shifted from the correct position,
Even if one of the two wafer clips 17 hits the wafer 18 earlier than the other, the wafer 1
No mechanical shock is applied to 8, and no internal defects or particles are generated. Moreover, the wafer 18 is naturally held in a correct position by the cooperation of the four actuators 1.

While holding the wafer 18 in this state, the entire wafer holding device 12 is moved to the wafer receiving section of another semiconductor manufacturing apparatus by the inter-apparatus transfer device. Even during this movement, each actuator 1 is fixed at both ends to the frame plate 13 so that the wafer 18
Vibration due to the inertia of the vehicle is minimized. When the air pressure is released at the destination, the actuators 1 return to the linear state, so that the wafer 18 is no longer held and is accepted by the semiconductor manufacturing apparatus. And the wafer holding device 12
Returns to the original place by the inter-apparatus transfer device to move the next wafer. From the above description, it can be understood that in this embodiment, an excellent wafer holding device 12 without impact is realized by combining an actuator that performs soft movement by applying air pressure and releasing pressure. Moreover, complicated air pressure control and the like are not required.

As described above in detail, the variable shape actuator according to this embodiment can perform a flexible movement without complicated air pressure control. Therefore, it is possible to provide an excellent flexible actuator which can be applied to a wafer transfer of a semiconductor manufacturing apparatus which dislikes an impact. The embodiments do not limit the present invention, and various modifications and improvements can be made without departing from the spirit of the present invention. For example, in the above embodiment, a cylinder was used as the compressed air source, but a compressor may be used. Further, the present invention may be applied to fields other than the semiconductor manufacturing apparatus.

[0031]

As is apparent from the above description, according to the present invention, unnecessary vibration does not occur, and therefore, high positional accuracy can be realized by flexible movement, and an excellent control mechanism is not required. Flexible actuator can be provided, and its effect is great. If such a flexible actuator is applied to, for example, the semiconductor manufacturing field, an excellent wafer transfer device that does not give a mechanical impact to a wafer can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a flexible actuator according to the present invention.

FIG. 2 is a plan view and a side view of a wafer holding device to which a flexible actuator according to the present invention is applied.

FIG. 3 is a sectional view of the wafer holding device shown in FIG. 2;

FIG. 4 is a plan view of the wafer holding device shown in FIG. 2 when pressurized.

FIG. 5 is an explanatory diagram showing an example of a flexible actuator according to the related art.

FIG. 6 is an explanatory diagram showing an example of a flexible actuator according to the related art.

FIG. 7 is an explanatory diagram showing an example of a flexible actuator according to the related art.

[Explanation of symbols]

 2 Tube 3 Peripheral reinforcing fiber 4, 5-axis reinforcing fiber 6, 7, 15 Tube holder

Claims (2)

(57) [Claims] 1. A flexible tube, a circumferential reinforcing fiber tightly wound around the entire length of the tube , and an axial reinforcing fiber joined in an axial direction of the tube.
In luer actuator, fixing a pair of opposite ends of the tubes face in parallel with each other
And the axial reinforcing fiber is on one side of the tube.
A pair of axial strength ends joined near the fixed part of the tube
He reduction made fibers, the central portion of the tube is the axial reinforcing fibers are bonded
Without expansion and contraction are free, by being pressed into the tube, the shaft strong chemical fiber
A shape-variable actuator, wherein a tube portion free of fibers is curved toward the one side surface. 2. The curved tube according to claim 1, wherein a plurality of variable shape actuators according to claim 1 are annularly arranged.
A variable-shape actuator characterized by gripping a conveyed object with a valve section.