JP5013083B2 - Substrate transfer robot with collision torque buffering mechanism - Google Patents

Description

  The present invention relates to a substrate transfer robot provided with a collision torque buffering mechanism for buffering an impact when a robot arm collides with surrounding equipment.

In semiconductor manufacturing and liquid crystal panel manufacturing, a substrate transfer robot has been conventionally used to transfer a substrate such as a wafer or a liquid crystal glass substrate to a desired position. This substrate transfer robot is composed of a hand portion for mounting a substrate, an arm portion for moving the hand portion, a turning portion for turning the arm portion, and the like, and is moved up and down (up and down) by relative rotation of joint portions connecting the respective portions. Rotation and expansion / contraction operations are possible. For the operation of each part of the substrate transfer robot, a rotary servo motor is usually used.
A reduction gear is attached to the output shaft of the servo motor, and the operation of each part is realized while obtaining high torque from the motor. The substrate transfer robot is taught a substrate transfer position via a teaching device connected to the robot controller, and thereafter, the substrate transfer robot repeatedly operates between the taught transfer positions to transfer the substrate. For example, the substrate is taken out from a cassette in which the substrate is inserted and transferred again to another cassette, or the substrate is transported to the manufacturing apparatus side or a target location.
On the other hand, in manufacturing apparatuses for semiconductor manufacturing and liquid crystal panel manufacturing, it is required to improve throughput and reduce the footprint of the apparatus. Therefore, the substrate transfer robot can transfer the substrate at a high speed within the minimum required operating range. It has been demanded.
A substrate transfer robot placed in such a situation may cause an incorrect transfer position or an operation error when an operator teaches, and the robot's hand may be placed on surrounding equipment (such as a cassette). There were many collisions.
Further, even during the so-called normal operation other than when teaching, a collision may occur without matching the timing of the operation of surrounding equipment, or a similar collision may occur due to a malfunction of the robot itself. When a collision occurs, the collision force is directly transmitted to the robot arm through the hand, and the motor speed reducer is damaged. In the case of replacement, the motor and speed reducer are covered with the arm cover. For this reason, complicated work is required for replacement.
As described above, the hand and the flange of the arm that supports the hand so as to be rotatable are directly connected, and the relative rotation cannot be performed between them. Therefore, the torque generated when the hand collides cannot be buffered.
Therefore, a robot having a collision prevention function that can sufficiently reduce the impact at the time of collision with an obstacle and can minimize mechanical damage to both the robot arm and the obstacle has been developed (for example, , See Patent Document 1).
JP-A-6-278081

  In the robot described in Patent Document 1, a tactile sleeve is elastically coupled to the outside of the robot arm, and a plurality of stress sensors for outputting stress signals by detecting the occurrence of stress at a plurality of support portions of the tactile sleeve with respect to the robot arm are provided. Each is attached and an arm position control device is connected to each stress sensor. Then, the presence / absence of the collision and the direction of the collision are detected based on the stress signal from the stress sensor, and the arm position control device detects the robot arm in the direction opposite to the direction of the stress generated in the tactile sleeve based on the collision detection signal. The position is controlled.

However, the collision prevention function of the robot described in Patent Document 1 has a special purpose of providing a hollow cylindrical tactile sleeve outside the robot arm for collision prevention detection. The surroundings are conversely bulky, and there was a drawback that what was not collided with only the original robot arm would induce a useless collision that would be detected as a collision because of this tactile sleeve .
Therefore, the present invention has a mechanism (collision torque buffering mechanism) that releases the impact force generated when the hand collides without any bulkiness around the robot arm, and can detect that a collision has occurred. It is an object of the present invention to provide a collision prevention device that buffers force transmission to the arm side, protects a robot speed reducer, and reduces damage to peripheral devices and hands.

In order to solve the above problem, the present invention is configured as follows.
The invention of the substrate transfer robot according to claim 1 is a substrate transfer robot comprising: a hand that mounts a substrate; and a horizontal articulated arm that rotatably supports the hand at a tip.
A hand side flange portion fixed between the hand and the tip of the arm and fixed to the hand, and fixed to the tip of the arm, and relative to the hand side flange portion by a constant frictional force during normal operation. It consists of a arm side flange portion for holding the hand-side flange portion so as not to rotate, when the collision torque at the time of collision of the hand exceeds the frictional force, the hand-side flange portion and the arm-side flange portion DOO comprises a collision torque cushioning mechanism slipping,
The hand-side flange portion is formed with a flat plate-shaped flange portion extending in the horizontal direction along the circumferential direction,
The arm-side flange portion generates the frictional force with the flange portion by sandwiching the flange portion from the vertical direction, and a sealing member is provided around the flange portion to surround the flange portion. Fill and seal with lubricant,
The collar portion and the arm-side flange portion are formed of different materials .
According to a second aspect of the present invention, in the substrate transfer robot according to the first aspect, the collar portion is made of brass, and the arm side flange portion is made of a stainless steel member .
According to a third aspect of the present invention, in the substrate transfer robot according to the first or second aspect, the sensor is provided on the outer peripheral side in the horizontal direction of the hand side flange portion, and the optical axis faces the horizontal direction, A detection plate provided on an outer peripheral side in the horizontal direction of the arm side flange portion and provided to face the sensor, and when the hand side flange portion and the arm side flange portion slide out, A sensor detects the detection plate, detects the relative rotation of the hand side flange portion and the arm side flange portion, and sends the detection signal to a robot controller .

According to the first and second aspects of the invention, in the apparatus for transporting a substrate at a high speed in a narrow space such as a substrate transport robot, even if the hand collides with another device, the hand is armed only when a certain impact or more occurs. Therefore, the torque at the time of collision can be buffered, and the speed reducer of the servo motor that drives the arm is not damaged. In addition, damage to the hand itself can be reduced.
Further, it is possible to stabilize a constant torque at which the flanges on the hand side and the arm side slide.
Also, slips against hand arm, the material of the hand-side flange portion and the arm-side flange are different, the so-called and bite (burn) can be prevented. According to the third aspect of the present invention, since the controller can detect that the hand has started sliding on the arm, the robot can be stopped on the controller side, and further damage to the hand can be avoided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a side view of a substrate transfer robot 20 provided with a collision torque buffering mechanism 10 of the present invention. The substrate transfer robot 20 is connected to the robot controller 29 and its operation is controlled. The robot 20 is fixed to a floor or the like via a base 21. One end of the first vertical arm 22 is supported on the base 21 so as to be rotatable about the C1 axis. A servo motor and a speed reducer (not shown) are accommodated on the C1 axis, and the first vertical arm 22 is rotated. On the other end of the first vertical arm 22, one end of the second vertical arm 23 is rotatably supported around the C2 axis. A servo motor and a speed reducer (not shown) are also accommodated in the C2 axis, and the second vertical arm 23 is rotated. On the other end of the second vertical arm 23, a swivel trunk base 34 is supported so as to be rotatable about the C3 axis. A swivel drum 25 is supported on the swivel drum base 34 so as to be rotatable around the θ axis. The swivel drum 25 is swung around the θ axis by a motor (not shown).
On the other hand, a link bar is provided along the second vertical arm 23 and the first vertical arm 22 to form a link mechanism 24. The distal end of the link mechanism 24 is connected to the revolving trunk base 34. As a result, regardless of the postures of the first vertical arm 22 and the second vertical arm 23, the revolving barrel 25 can always maintain a constant posture, and the revolving motion of the first vertical arm 22 and the second vertical arm 23 turns. The body 25 can move up and down (up and down) in the Z direction.

FIG. 2 is a partial view seen from A in FIG.
In FIG. 2, two sets of horizontal articulated arms in total are provided on the upper surface of the revolving drum 25 on the L side and the R side, that is, on the left and right sides in the figure. The configuration of the horizontal articulated arm on the L side (left side) will be described as a representative, but the basic configuration is the same on the R side, so the description of the configuration on the R side is omitted.
In addition, since the subscripts of the numbers L and R in the drawing represent the left side and the right side, respectively, in the following description, it will be assumed that the left and right are not distinguished when not described.
One end of the first horizontal arm 26L is supported on the revolving drum 25 so as to be rotatable in the horizontal direction about the 31L axis. As shown in FIG. 1, one end of the second horizontal arm 27L is supported on the other end of the first horizontal arm 26L so as to be rotatable in the horizontal direction about the 33L axis. A belt (not shown) is stretched inside the first horizontal arm 26L and the second horizontal arm 27L, and the respective arms around the 31L axis and the 33L axis are simultaneously rotated by rotation of a servo motor and a speed reducer (not shown). Rotate. At the other end of the second horizontal arm 27L, the arm tip flange 11 is supported so as to be rotatable about the 32L axis.
Further, one end of the collision torque buffer mechanism 10 of the present invention is fixed to the arm tip flange 11, and a hand 28L is fixed to the other end. A substrate 61a is mounted on the hand 28L. When the first horizontal arm 26 and the second horizontal arm 27 rotate, the arm tip flange 11 rotates relative to each arm and maintains the rotation angle. And the hand 28 expands and contracts in the X direction (left-right direction) in FIG. 1 while maintaining its posture.

The substrate transport robot 20 transports the substrate 61 to a desired position while mounting the substrate 61 on the hand 28 by reproducing the teaching position (transport position) stored in advance in the controller 29 by the configuration and operation described above. To do.
However, as described above, when the teaching operation is performed on the substrate transfer robot 20, the servo motor that drives the first horizontal arm 26 and the second horizontal arm 27 when the hand 28 collides with surrounding devices. In this case, the reduction gear of this type or the reduction gear of the servo motor that drives the swivel drum 25 is forcibly rotated from the output side, so that the reduction gear is damaged at this time.
Therefore, in the present invention, the collision torque buffering mechanism 10 is provided between the arm tip flange 11 and the hand 28. Hereinafter, the collision torque buffer mechanism 10 will be described in detail.

3A and 3B are diagrams for explaining the collision torque buffering mechanism of the present invention. FIG. 3A is a top view, FIG. 3B is a side view, only a portion related to the collision torque buffering mechanism is shown in a sectional view, and FIG. It is the figure which looked at from the sensor side.
In the figure, reference numeral 10 denotes a collision torque buffering mechanism according to the present invention. The collision torque buffering mechanism 10 is generally composed of an arm side flange portion 51, a hand side flange portion 52, and a slip detection mechanism 40.

The arm side flange 51 includes an arm side A flange 12 whose one end is fixed to the arm distal end side flange 11 by a screw 11 a and an arm side which is fixed to the other end of the arm side A flange 12 by a screw 14. B flange 13. Both flanges are ring-shaped flanges.
The hand side flange portion 52 includes a hand side B flange 16 whose one end is fixed to the hand 28 by a screw 19 and a hand side A flange 15 which is fixed to the other end of the hand side B flange 16 by a screw 18. And is composed of. Both flanges are ring-shaped flanges.
The arm side A flange 12 holds the flange portion of the hand side A flange 15 between the arm side A flange 15 and the arm side B flange 13. Specifically, the flange portion protruding to the outer peripheral side of the hand side A flange 15 is formed by the upper surface of the flange protruding to the inner peripheral side of the arm side A flange 12 and the lower surface of the inner peripheral side of the arm side B flange 13. Hold it.
Further, an O-ring 17 a is sandwiched between the contact surfaces of the arm-side A flange 12 and the arm-side B flange 13 and corresponding to the inside of the screw 14. Similarly, an O-ring is sandwiched between the inner peripheral surface of the arm side B flange 13 and the outer peripheral surface of the hand side A flange 15 above the collar portion. Similarly, an O-ring is also sandwiched between the upper surface of the collar protruding to the inner peripheral side of the arm side A flange 12 and the lower surface of the hand side A flange 15. Then, a lubricant (grease) is filled in a space of a minute gap surrounded by the O-rings 17a to 17c.
With the above configuration, the arm-side flange portion 51 and the hand-side flange portion 52 are sandwiched between the arm-side A flange 12 and the arm-side B flange 13 because the arm-side flange 15 holds the flange portion of the hand-side A flange 15. The state which does not rotate relatively by the frictional force of the part is maintained. However, when the arm-side flange portion 51 and the hand-side flange portion 52 receive a relatively rotating force with a certain torque or more, they rotate (slide) by the action of the lubricant.
This slipping torque is less than the torque that the speed reducer of the servo motor that drives the horizontal arm can withstand, and when the horizontal arm operates or the swivel cylinder operates, do not slip with the rotational torque received by the inertial force. Pre-adjust further.
In order to maintain the reproducibility of this constant torque, the surface accuracy of each flange surface holding the frictional force is improved to a constant value, and the amount of lubricant is adjusted. Further, in order to prevent so-called galling when slipping, the material of the flanges of the arm side A flange 12 and the arm side B flange 13 and the material of the flange of the hand side A flange 15 are different. Here, the material of the flanges of the arm side A flange 12 and the arm side B flange 13 is made of stainless steel, and the hand side A flange 15 is made of brass.

The slip detection mechanism 40 includes a sensor support member 41 having one end fixed to the outer peripheral portion of the hand side B flange 16, a sensor 42 fixed to the other end of the sensor support member 41, and an outer periphery side of the arm side A flange 12. The detection plate support member 44 is fixed at one end, and the detection plate 43 is fixed at the other end of the detection plate support member 44.
The sensor 42 is a reflective optical fiber sensor. The output side tip of the sensor 42 and the detection plate 43 face each other so that the optical axis of the sensor 42 hits the detection plate 43. FIG. 3C shows the detection plate 43 viewed from the sensor 42 side. The detection plate 43 is formed with a long hole-shaped through hole 43b, and a bridge 43a having a very small width is formed at the center thereof. The light beam of the sensor 42 is reflected by the bridge 43a, and the sensor 42 is adjusted so as to be always ON. On the other hand, when the light beam of the sensor 42 comes off the bridge 43a, the reflected light does not return to the sensor side by the through hole 43b, and the sensor is turned off. The cable of the sensor 42 is connected to an amplifier (not shown), and the signal is input to the robot controller 29. When the sensor 42 is turned off, the substrate transfer robot 20 is set to decelerate and stop.
The slip detection mechanism 40 is configured so that the optical axis of the sensor 42 faces in the horizontal direction as shown in FIG. 3B, so that even if it is provided between the hand 28 and the arm tip flange 11, it does not collide. The torque buffer mechanism 10 can be made thin.

  The collision torque buffering mechanism 10 configured as described above is configured so that when the hand 28 collides with surrounding equipment during teaching of the substrate transfer robot 20 or the like, the collision torque applied to the collision torque buffering mechanism 10 at the time of the collision is reduced by the arm side flange portion. Since the arm side flange 51 and the hand side flange 52 begin to slide with each other if the holding force is greater than the holding force due to the friction between the hand 51 and the hand side flange 52, in this case, the hand side flange 52 on the hand 28 side It slides with respect to the arm side flange portion 51 together with the hand 28. At this time, in the slip detection mechanism 40, since the optical axis of the sensor 42 is deviated from the bridge 43a of the detection plate 43, the reflected light of the sensor does not return and the sensor is turned off. When the robot controller 29 detects the sensor OFF, the substrate transfer robot 20 is decelerated and stopped.

  As described above, conventionally, the hand 28 and the arm end flange 11 are directly connected, and the relative rotation cannot be performed between them, so that the torque generated at the time of the collision of the hand cannot be buffered, and the collision is prevented. Even if there is a device, the device itself causes the arm itself to be bulky and cause a collision. However, in the present invention, a collision torque buffering mechanism is not provided between the hand 28 and the arm tip flange 11 instead of the type surrounding the arm. 10 is provided, the relative rotation is possible when the hand side and the arm side are rotated at a certain torque or more, and therefore, the collision torque is applied to the motor driving the horizontal arm and its reduction gear when the hand collides. Since it becomes difficult to transmit, these can fully protect. In addition, since the damage of the hand 28 is minimized, after the collision, the hand 28 can be recovered by simply returning the relative positional relationship between the arm side flange portion 51 and the hand side flange portion 52 to the original state. Moreover, it is possible to reliably detect a collision.

It is a side view of the board | substrate conveyance robot provided with the collision torque buffering mechanism of this invention. It is the fragmentary view seen from A in FIG. It is a figure which shows the collision torque buffer mechanism of this invention, (a) is a top view, (b) is a sectional side view, (c) is the figure which looked at the detection plate from the sensor side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Collision torque buffer mechanism 11 Arm tip flange 12 Arm side A flange 13 Arm side B flange 14 Screw 15 Hand side A flange 16 Hand side B flange 17 O ring 18 Screw 19 Screw 20 Substrate transport robot 21 Base 22 First vertical arm 23 Second vertical arm 24 Link mechanism 25 Swivel drum 26 First horizontal arm 27 Second horizontal arm 28 Hand 29 Robot controller 31 First horizontal arm rotary shaft 32 Hand rotary shaft 33 Second horizontal arm rotary shaft 34 Swivel drum base 40 Slip detection mechanism 41 Sensor support member 42 Sensor 43 Detection plate 43a Bridge 43b between through holes Long hole shape through holes (2)
44 Detection plate support member 51 Arm side flange portion 52 Hand side flange portion 61 Substrate

Claims (3)

In a substrate transfer robot comprising a hand for mounting a substrate, and a horizontal articulated arm that rotatably supports the hand at the tip,
A hand side flange portion fixed between the hand and the tip of the arm and fixed to the hand, and fixed to the tip of the arm, and relative to the hand side flange portion by a constant frictional force during normal operation. It consists of a arm side flange portion for holding the hand-side flange portion so as not to rotate, when the collision torque at the time of collision of the hand exceeds the frictional force, the hand-side flange portion and the arm-side flange portion DOO comprises a collision torque cushioning mechanism slipping,
The hand-side flange portion is formed with a flat plate-shaped flange portion extending in the horizontal direction along the circumferential direction,
The arm-side flange portion generates the frictional force with the flange portion by sandwiching the flange portion from the vertical direction, and a sealing member is provided around the flange portion to surround the flange portion. Fill and seal with lubricant,
A substrate transfer robot, wherein the collar portion and the arm side flange portion are made of different materials . The buttocks are made of brass,
The substrate transfer robot according to claim 1, wherein the arm side flange portion is made of a stainless steel member. Provided on the outer peripheral side in the horizontal direction of the hand side flange portion, provided on the outer peripheral side in the horizontal direction of the arm side flange portion, and provided to face the sensor. And the sensor detects the detection plate when the first hand side flange portion and the arm side flange portion slide out, and the hand side flange portion and the arm side flange portion The substrate transfer robot according to claim 1 , wherein occurrence of relative rotation of the substrate is detected and a detection signal is sent to the robot controller .

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