JPH05228880A - Robot - Google Patents

Abstract

PURPOSE:To provide a robot that is excellent in positioning accuracy in addition to undusty and nonlubricant, and besides, suitable for use in special surroundings such as a semiconductor manufacturing process or the like where high cleanliness is required. CONSTITUTION:This robot is featured as follows; an arm 2 providing the teeth of a magnetic body is supported by means of noncontact, while it is shifted in the horizontal direction and provided with a horizontal driving part 3 consisting of an electromagnet group arranged in the horizontal direction rocking it in the vertical direction and three means 5, 6 and 7 rotating the horizontal driving part, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot, and more particularly to a robot that can be used in a special environment (in space, in a vacuum, in a clean room, in a liquid) where dusting and lubrication are problems.

[0002]

2. Description of the Related Art For example, in a semiconductor manufacturing process,
The following measures are required for robots used in a clean room to maintain high cleanliness. (1) Uses a low-dust and non-dust generation mechanism. Eliminate or reduce dust generating elements and adopt low dust generating or no dust generating mechanism. (2) Built-in dustproof mechanism. A dustproof mechanism is incorporated to prevent the outflow of internally generated particles and to prevent their diffusion. (3) Improvement of reliability and maintainability. Aiming for maintenance-free by improving reliability and maintainability.

The following methods are available as specific countermeasures. (1) Suction of internal negative pressure A negative pressure is created inside the robot to constantly create a flow of air from the outside to the inside so that dust does not flow out through the portion opened to the outside. (2) Magnetic fluid seal Magnetic fluid completely separates the inside and outside of the robot,
Prevents diffusion of dust from inside. (3) AC Servo Motor Since it has no brush, it produces less dust than the conventional DC servo motor and maintenance is free.

[0004]

Under special environments such as space, vacuum, clean room, and liquid, there are problems such as dust generation from the contact portion of the actuator and lubrication of the bearing portion. For example, in the field of semiconductor manufacturing, high integration of LSI is advanced, and a manufacturing environment and apparatus with higher cleanliness are required. For this reason, currently unmanned manufacturing processes are being promoted, but dust generation from the inside of the robot used, maintenance of parts requiring lubrication, and the like have become problems. At present, in order to deal with these problems, the above-mentioned countermeasures are taken such as providing a dust-proof mechanism to the robot that is a dust source.

The present invention has been made in view of the above circumstances, and the object thereof is to realize a small-sized robot with high positioning accuracy, no dust generation, and no lubrication without taking measures such as providing a dustproof mechanism. However, it is to provide a robot that can be used without problems even in a special environment.

[0006]

A robot according to the present invention is arranged in a horizontal direction in which an arm having teeth of a magnetic material is supported in a non-contact manner, and is horizontally moved and vertically swung. And a means for rotating the horizontal drive section.

[0007]

According to the robot of the present invention, in the horizontal drive unit, the arm having the hand at the tip is supported by the magnetic bearing in a non-contact manner, no dust is generated, no lubrication is required, and the atmosphere is not polluted. Maintenance free. Further, the linear pulse motor enables highly accurate positioning, and provides a robot suitable for use in a special environment.

[0008]

1 is a structural diagram of a robot according to a first embodiment of the present invention. The arm 2 of the robot has a hand 1 at its tip, on which a transported object such as a semiconductor wafer is placed. The arm 2 is provided with a horizontal drive unit 3 having magnetic teeth and composed of electromagnet groups arranged in a horizontal direction, which functions as a magnetic bearing and a linear pulse motor.
It is driven in the horizontal direction without contact and conveys semiconductor wafers and the like. The horizontal drive unit 3 is connected to the arm 2 as shown by a dotted line.
Hand 1 can be vertically swung, and the arm 2
By raising and lowering the hand 1 at the tip of the hand, operations such as handing over the semiconductor wafer or the like placed on the hand 1 to the wafer processing chamber 12 can be performed.

Furthermore, means for rotating the horizontal drive unit 3 is provided. That is, when the servo motor 5 rotates, the pulley 7 rotates via the belt 6, and the horizontal drive unit 3 fixed to the pulley 7 rotates. Here, since the servomotor 5, the belt 6, the pulley 7, and the horizontal drive unit 3 are sealed in the can 9, there arises a problem that the environment is polluted by the gas generated by mechanical contact or electromagnet wiring. Absent.

Therefore, the robot of the present embodiment has the arm 2
Can be oscillated in the vertical direction (moved up and down by a slight distance) and moved in the horizontal direction in a non-contact supported state, and the arm 2 can be rotated about the pulley 7 as an axial center. You can exercise. For example, the wafer processing chamber 1
The semiconductor wafer is placed on the hand 1 by raising the hand 1 by a slight distance 2 and the arm 2 is returned horizontally.
Next, move the arm 2 to the right,
Move horizontally until the position is reached. Next, the servo motor 5 is driven to rotate the horizontal drive unit 3, that is, the arm 2 to move the semiconductor wafer to the front of another wafer processing chamber (not shown). Then, the arm 2 is extended in the horizontal direction by the horizontal drive unit 3, the hand 1 is moved to another wafer processing chamber, and the hand 1 at the tip is swung (lowered by a slight distance), so that the semiconductor wafer is processed by another processing. Can be handed over to the room.

FIG. 2 is a structural view of the arm, (A) is a side view, and (B) is a plan view. The hand 1 is attached to the tip of the arm 2 and is made of a thin aluminum plate, on which an object to be conveyed such as a semiconductor wafer 11 is placed, as shown in FIG. The arm 2 itself is made of a magnetic material having high magnetic permeability, and the teeth 21 of the magnetic material are provided on the front surface and the back surface thereof.
Equipped with. As shown in (A), the horizontal drive unit 3 is
As a magnetic bearing and linear pulse motor, the arm 2 is supported in a non-contact floating state, the arm 2 is moved in the horizontal direction, and the hand 1 at the tip is swung in the vertical direction.

FIG. 3 is a structural diagram of the horizontal drive unit,
(A) is a plan view of an arm having teeth of a magnetic material, and (B) is a plan view of a horizontal drive unit where the surfaces of the arms face each other. As shown in (A), the surface of the arm 2 is provided with a tooth 21 which is an unevenness of a magnetic material in the center and thick plate-like portions 22 on both sides. As shown in (B), the horizontal drive unit 3 is
Electromagnets 31, 32, 33, 34 that serve as horizontal (Y) and vertical (Z) direction magnetic bearings, and electromagnets 36, 3 that serve as linear pulse motors that drive the arm 2 in the horizontal (X) direction.
7, 38 are arranged in the horizontal direction. The Y-direction and Z-direction position sensors 41, 42, 43, 44 detect the positions of the plate-like portions 22 on both sides of the opposing arm 2 to support the arm 2 to float at a predetermined position. , 33, 34 are controlled. The X-direction position sensors 46 and 47 detect the positions of the teeth of the unevenness of the arm 2 and sequentially and selectively enhance the excitation of the electromagnets 36, 37 and 38 to drive the arm 2 in the horizontal (X) direction.

The electromagnets 36, 37 and 38 constitute a three-phase linear pulse motor, and the positions of the yokes of the electromagnets 36, 37 and 38 are displaced by 120 ° with respect to the pitch of the arm teeth 21. ing. Therefore, the electromagnets 36, 3
By selectively increasing the excitation of 7 and 38 sequentially, the convex portions of the teeth 21 of the magnetic body are sequentially attracted to the magnetic poles of the electromagnet by the magnetic attraction force, and the arm 2 moves in the horizontal direction.
The line AA ′ in (B) corresponds to the position of the center line AA ′ of the arm in (A), and the line BB ′ in (B) corresponds to the position B of the end of the arm in (A). Corresponds to the position of the -B 'line.

FIG. 4 is a sectional view of the horizontal drive section,
3A is a cross section taken along the line AA ′ of FIG.
3B is a cross section taken along the line BB ′ of FIG.
As shown in the cross-sectional view of FIG. 4A, the arm 2 is levitated in the vertical (Z) direction, and sequentially magnetizes electromagnets 36, 37, and 38 constituting the linear pulse motor, thereby ) Direction. Electromagnets 36, 37, 3
The magnetic poles of No. 8 are displaced from each other by 120 ° in phase angle with respect to the pitch of the teeth 21 of the arm 2.

Further, as shown in the sectional view of FIG. 4 (B), the plate-like portions 22 at both ends of the arm 2 are floated in the vertical (Z) direction in a non-contact manner by the electromagnets 32 and 34 constituting the magnetic bearings. Will be supported in the condition Z direction position sensor 42,
44 controls the floating position of the plate-shaped portion 22 by detecting the position of the arm from the plate-shaped portions 22 at both ends of the arm 2 and adjusting the excitation of the electromagnets 32 and 34.

The operation in which the horizontal drive unit 3 swings the hand 1 of the arm 2 in the vertical direction (Z direction) (moves a slight distance) also serves as electromagnets 31, 32, 33, 34 constituting the magnetic bearing.
Is performed by controlling the excitation current of the. Since the hand 1 at the tip of the arm 2 is located several times farther than the distance between the electromagnets 32 and 34 from the horizontal drive unit, the swing width (movement width) of the hand 1 in the (Z) direction. Is an electromagnet 32,3
It becomes several times larger than the swing width between four. The swing width is determined by detecting the position of the arm 2 by the Z direction position sensors 42 and 44, and the electromagnets 32U, 32D, 34U and 34 are detected.
It is controlled by adjusting the excitation of D respectively. The electromagnets 31, 33 supporting the other side of the plate-shaped portions 22 on both sides of the arm 2 are also electromagnets 32, 34 so that the axis of the arm 2 in the horizontal (Y) direction is maintained horizontal.
Is excited as in.

FIG. 5 is a sectional view of the horizontal drive section,
3A is a cross section taken along the line CC ′ of FIG. 3, and FIG.
Is a cross section taken along the line D-D 'in FIG. As shown in (A), both ends of the plate-shaped portions 22 on both sides of the arm 2 are positioned immediately below the yokes of the electromagnets 33 and 34, respectively, being displaced in the Y direction. Therefore, the magnetic flux generated from the yokes of the electromagnets 33 and 34 is concentrated on both ends of the plate-like portion 22 on both sides of the arm 2, and a strong magnetic attraction force and a shearing force are generated there, so that the arm 2 is vertically (Z) and horizontal. Support in the (Y) direction. As shown in (B), the magnetic flux of the yoke of the electromagnet 36 is formed in the teeth 21 of the arm 2 via the air gap, and is driven in the horizontal (X) direction by this magnetic attraction force.

FIG. 6 is a structural diagram of a robot according to the second embodiment of the present invention. (A) is a side view of a horizontal drive unit of the robot, and (B) is a plan view of an arm. It is common to the robot according to the first embodiment that the arm 2 having magnetic teeth is supported in a non-contact manner, and that the arm 2 is provided with a horizontal drive unit 3 that moves the arm 2 horizontally and swings the arm vertically. The hand 1 at the tip of the arm 2 conveys the semiconductor wafer 11 and the like with three degrees of freedom of horizontal, swing, and rotation, which is also common to the robot of the first embodiment.

The point different from the robot of the first embodiment is that the means for rotating the horizontal drive unit is concentric to rotate the horizontal drive unit 3 fixed to a disk-shaped magnetic body 15 having radial teeth. The point is that the rotary drive unit 16 including an array of disk-shaped electromagnets is provided. This rotation drive unit 1
6, the disk-shaped magnetic body 15 equipped with the horizontal drive unit 3
Can be rotated as a rotor of a stepping motor.

FIG. 7 is a structural diagram of the rotary drive unit and the horizontal drive unit. The rotation drive unit 16 includes disk-shaped electromagnets 25, 26, 27 and rotation angle sensors 28, 2 arranged concentrically.
9 is a stator of a disk-shaped stepping motor that rotates a disk-shaped magnetic body 15 having radial teeth. The horizontal drive unit 3 composed of electromagnet groups arranged in the horizontal direction is the same as that described in detail in the first embodiment, and FIG. 8A is a structural diagram of the arm and FIG.
Fig. 2 shows the structure of the horizontal drive unit. As shown in FIG. 7, the upper surface and the lower surface of the horizontal drive unit 3 are fixed to a magnetic body 15 having radial teeth on a disk-shaped surface.

FIG. 9 is a plan view of a disk-shaped magnetic body 15 having radial teeth. The disk-shaped magnetic body 15 is provided with radial irregularities (teeth) 23 having a constant pitch, and the electromagnet group constituting the horizontal drive unit 3 is fixed to the opposite surface. The radial teeth 23 are given a rotational torque by the magnetic attraction force of the electromagnet groups 25, 26, 27 that are arranged concentrically and form a rotation drive unit.

FIG. 10 is a plan view of a group of electromagnets that are arranged in a concentric circle and form a rotary drive unit. The concentric electromagnets 25, 26, 27 each include a coil wound in an annular shape, and a yoke provided so as to surround the coil, and the yoke has irregularities (teeth) as shown in FIG. ing. The tooth pitch of the yoke is determined by the electromagnets 25, 26,
27, the phases are shifted by 120 °. Therefore, by sequentially exciting the electromagnets 25, 26, and 27 with pulses, the radial teeth 23 of the magnetic body 15 facing each other.
Are sequentially attracted to the yokes of the electromagnets 25, 26, 27 by the magnetic attraction force, and the disk-shaped magnetic body 15 having the radial teeth 23 rotates. The details of the disk-shaped stepping motor having such a structure are disclosed in Japanese Patent Application No. 3-17619.

[0023]

As is apparent from the above description, according to the robot of the present invention, the horizontal drive unit for horizontally moving and vertically swinging the arm is supported by the magnetic bearings in a non-contact manner. No dust is required and lubrication is not required.
In addition, since the electromagnet, the wiring, and the like are sealed by the can in the rotary drive unit that rotates the arm, contamination in the atmosphere is prevented and the maintenance is free. Further, since the horizontal drive unit can be positioned with high accuracy by a linear pulse motor, a robot suitable for use in a special environment such as a semiconductor manufacturing process with high cleanliness has been realized.

[Brief description of drawings]

FIG. 1 is a structural diagram of a robot according to a first embodiment of the present invention.

FIG. 2 is a structural diagram of an arm of the robot according to the first embodiment of the present invention.

FIG. 3 is a structural diagram of a horizontal drive unit of the robot according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a horizontal drive unit of the robot according to the first embodiment of the present invention.

FIG. 5 is a sectional view of a horizontal drive unit of the robot according to the first embodiment of the present invention.

FIG. 6 is a structural diagram of a robot according to a second embodiment of the present invention.

FIG. 7 is a structural diagram of a rotation drive unit and a horizontal drive unit of a robot according to a second embodiment of the present invention.

FIG. 8 is a structural diagram of a horizontal drive unit of a robot according to a second embodiment of the present invention.

FIG. 9 is a plan view of a magnetic body of the robot according to the second embodiment of the present invention.

FIG. 10 is a plan view of a rotation drive unit of the robot according to the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hand 2 Arm 3 Horizontal drive part 5 Servo motor 6 Belt 7 Pulley 9 Can 11 Semiconductor wafer 12 Wafer processing chamber 15 Magnetic material with radial teeth 16 Rotation drive part 21,23 Magnetic material tooth 22 Plate part 25, 26 , 27 Disc-shaped electromagnet 28, 29 Rotation angle sensor 31, 32, 33, 34 Magnetic bearing electromagnet 36, 37, 38 Linear pulse motor electromagnet 41, 42, 43 Concentric electromagnet

Claims (3)

[Claims] 1. A horizontal drive unit comprising electromagnet groups arranged in a horizontal direction for supporting an arm provided with magnetic teeth in a non-contact manner, moving the arm horizontally, and swinging the arm vertically. And a means for rotating the horizontal drive unit. 2. The robot according to claim 1, wherein the horizontal drive unit and the means for rotating the horizontal drive unit are sealed in a can. 3. A means for rotating the horizontal drive unit, wherein the horizontal drive unit fixed to a disk-shaped magnetic body having radial teeth is formed by a group of disk-shaped electromagnets arranged concentrically to form the radial teeth. The robot according to claim 2, wherein the robot is rotated by applying a magnetic attraction force to the robot.