JP4258851B1 - Articulated robot - Google Patents

Abstract

The present invention provides an articulated robot that is easy to maintain.
SOLUTION: A hand unit 8 on which a conveyed product is placed, and is connected to the hand unit 8, and includes at least two or more rotary joints 3, 4, and 5, so that the hand unit 8 moves in one direction. The articulated arms 21 and 22 arranged to expand and contract and face each other in the vertical direction, the moving mechanism 11 attached to the column 12 to move up and down, and the articulated arms 21 and 22 In a multi-joint robot comprising a support member 10 for connecting the two and a pedestal 13 connected to the lower end of the column 12 and turning the multi-joint arms 21 and 22 attached to the column 12, the pedestal 13 is turned. The fixed surface of the output shaft 39 of the reduction gear 37 to be moved is located at the approximate center of the thickness of the bearing 42 that supports the pedestal 13.
[Selection] Figure 4

Description

  The present invention relates to an articulated robot that takes a thin plate-like work such as a liquid crystal glass substrate or a semiconductor wafer into and out of a stocker.

Conventional articulated robots have been proposed that reduce the turning radius of the articulated robot when the pedestal is rotated by offsetting the rotational center of the shoulder joint and the rotational center of the pedestal (for example, , See Patent Document 1).
As shown in FIG. 6, the conventional articulated robot 1 includes two sets of arms 2 that are rotatably connected by joint portions 3, 4, and 5 to transmit a rotational force from a rotational drive source and perform a desired operation. Therefore, the rotation center axis of the joint portion 3 at the base end provided on the two sets of arms 2 is arranged vertically (or axially).
The articulated robot 1 is provided with two sets of arms 2, one arm drive type device 2 is used for supplying and the other is used for taking out, and the supply operation of the workpiece 9 and the extraction operation of another workpiece 9 are performed simultaneously. It is possible.
Further, the conventional articulated robot 1 is configured such that the hand portion 8 that holds the workpiece 9 by the arm 2 can be linearly moved in the direction of taking out and supplying the workpiece 9 indicated by an arrow X in the drawing.
Further, the conventional articulated robot 1 includes a moving member 11 (hereinafter, referred to as a vertical movement mechanism 11) that moves the support member 10 provided with the arm 2 up and down, and can adjust the vertical position of the arm 2. It is said. The pedestal 13 of the vertical movement mechanism 11 is provided so as to be rotatable so that the articulated robot 1 can be turned to change its direction.
Further, in the conventional articulated robot 1, the pedestal 13 is placed with respect to the base 14 in the direction indicated by the arrow Y in the figure, that is, in the direction orthogonal to the moving direction of the hand portion 8 and the vertical moving direction of the support member 10. The position of the vertical movement mechanism 11 can be adjusted.
Further, the two sets of arms 2 provided in the conventional articulated robot 1 have, for example, a plurality of joint portions, that is, the articulated robot 1 is configured as a horizontal articulated robot. The arm 2 in this embodiment includes a first arm 6 (hereinafter referred to as the upper arm 6), a second arm 7 (hereinafter referred to as the forearm 7) connected to the upper arm 6, and a work 9 connected to the forearm 7. And a hand portion 8 for holding the.
The base end of the upper arm 6 is connected to the support member 10 via a drive shaft, and constitutes a rotatable joint 3 (hereinafter referred to as a shoulder joint 3). This shoulder joint 3 becomes the joint 3 at the base end of the arm 2. Further, the distal end of the upper arm 6 and the proximal end of the forearm 7 are connected via a drive shaft to constitute a rotatable joint 4 (hereinafter referred to as an elbow joint 4). Further, the tip of the forearm 7 and the hand portion 8 are connected via a drive shaft to constitute a rotatable joint portion 5 (hereinafter referred to as a hand joint portion 5). It arrange | positions so that it may face in the up-down direction so that the rotation center axis | shaft of the shoulder joint part 3 may be coaxial.
The arm 2 rotates the shoulder joint 3, the elbow joint 4, and the hand joint 5 by a rotation drive source (not shown), and moves the hand 8 in the workpiece take-out / supply direction. At this time, in the arm 2, due to the mechanism, the hand portion 8 faces in one direction, the extended position where the upper arm 6 and the forearm 7 are fully extended, and the contracted position where the upper arm 6 and the forearm 7 are folded. The telescopic movement is performed so as to move in a straight line.
Here, the conventional articulated robot 1 is designed so that the center of the work 9 held by the hand unit 8 coincides with the rotation center of the pedestal 13 at the contracted position of the arm 2 shown in FIG. ing. Further, when the pedestal 13 is rotated by offsetting the rotation center of the shoulder joint portion 4 and the rotation center of the pedestal 13 in a direction orthogonal to the moving direction of the hand portion 8, it is necessary around the multi-joint robot 1. The turning radius of the articulated robot 1 can be reduced by preventing the elbow joint 4 and the hand 8 from projecting from the minimum region circle 15.
Further, a conventional articulated robot has been proposed in which the rotation of the electric motor is transmitted to the differential reduction gear by a belt and the rotation of the differential reduction gear is supported by a bearing (for example, see Patent Document 2).
In the conventional articulated robot turning structure, as shown in FIG. 8, the motor 102 is mounted upside down in the vicinity of the outer peripheral portion of the substantially cylindrical rotating member 104. The toothed pulleys 191 and 192 and the toothed belt 109 mounted on the coupled drive input shaft 193 serve to supply a rotational driving force. The speed reduction mechanism 103 is attached to a fixed member 105, and the top of the rotating member 104 is attached by a robot base 117 and a bolt 116, and is rotatably held with respect to the fixed member 105 by a bearing 112 at the bottom.
JP-A-2001-274218 (pages 4 to 5, FIGS. 1 and 2) JP-A-2-160485 (pages 2 to 3, FIG. 1)

Articulated robots for loading and unloading thin plate-like workpieces such as glass substrates for liquid crystals and semiconductor wafers into the stocker are required to be processed in a short time as the number of substrates to be processed increases and the number of substrates to be processed increases. For this reason, it is necessary for the robot to keep the path line for loading and unloading workpieces low, even though the equipment itself becomes large until the stocker for placing the substrate reaches the ceiling. . In other words, it is possible to place more boards on the stocker by making the path line so high that it reaches the ceiling from the high path line, and the height direction can be used effectively for articulated robots. It is requested.
In addition, realization of high speed and high accuracy is a major issue. On the other hand, large-scale equipment requires a large amount of capital investment in order to keep the cleanliness of the surroundings clean. For this reason, it is desirable to arrange and process more substrates in the stocker. . For this purpose as well, it is desired to be able to move in the vertical direction from the high pass line to the low pass line described above.
Further, regarding the cleanliness, the robot used to ensure the cleanness needs to be configured so that the inside of the robot is not exposed. For this reason, the drive mechanism of the robot to be used is required to be disposed inside the robot.
In addition, the number of liquid crystal substrates and semiconductor wafers produced is increasing year by year, and robots are required to have a transfer throughput in order to increase productivity. However, since the robot includes mechanical parts, maintenance is required, and the maintenance time is a large factor related to the throughput, and it is desired that the robot can be easily maintained. As for maintenance, it is a matter of course that the work for exchanging the power is generated. Most of the replacement work is replacement of the reduction gear. The problem was how to easily replace this reduction gear. In particular, when the pedestal turns, the column, arm and hand moments act on the driven reducer, so the pedestal turning shaft reducer is likely to be damaged.
In response to such problems, conventional articulated robots maintain the column, the arm attached to the column, and the pedestal turning mechanism that turns the hand because the reduction gear is directly connected to the pedestal. In order to replace the built-in speed reducer, it is necessary to work separately supporting the column, and since it cannot be easily maintained, it takes time to replace the speed reducer, which reduces productivity. There was a problem.
Further, the conventional articulated robot has a structure in which the arm base ends are arranged coaxially in the vertical direction. For this reason, in order to replace the motor or pulley, which is a mechanical component arranged at the base end of the arm, it is necessary to take a method such as replacing it after removing one arm, so the maintenance time is enormous. However, there has been a problem that productivity is lowered.
Further, in the structure of the conventional articulated robot turning mechanism, if the arm is arranged on the turning mechanism like a general vertical articulated robot, the upper moment can be obtained even in the configuration in which the bearing is arranged at the bottom. There is no problem because the load does not act greatly, but a large moment load acts when the side column is swung through the pedestal. Then, since the output plane of the reducer and the support plane of the bearing do not match, the moment load during turning will act greatly, and not only the reducer but also the bearing will be damaged, making maintenance difficult. There was a problem.
Also, it is necessary to lower the work pass line, but the turning mechanism shown in FIG. 8 has an unnecessary space inside, and even if this is combined with a conventional articulated robot, a low pass line can be formed. Because it was not possible, there was a problem that the work could not be taken in and out of the lower part of the stocker.
The present invention has been made in view of such problems, and an object thereof is to provide an articulated robot that can be easily maintained and can realize a low pass line.

In order to solve the above problems, the present invention is configured as follows.
Invention of Claim 1 is connected with the hand part which mounts a conveyed product, and the hand part, is provided with at least two or more rotary joints, and expands and contracts to move the hand part in one direction, A multi-joint arm arranged to oppose the vertical direction; a movement mechanism attached to the column to move up and down; a support member for connecting the movement mechanism and the multi-joint arm; and a lower end of the column In a multi-joint robot configured such that the pivot axis of the pedestal is offset and connected to the column so as to be orthogonal to the moving direction of the hand and the direction in which the articulated arm moves up and down having a first fixing member for fixing said pedestal with the output shaft of reduction gear which, fixed surface of the output shaft of said reduction gear and said first fixing member, about said pivot axis of said seat Deceleration Located between the thickness of the cross roller bearing for supporting the pedestal disposed outside with respect to the radial direction of the fixed to the second fixing member outer race of the cross roller bearing is arranged in a base fixed to the base It has been done .
According to a second aspect of the present invention, the speed reducer is disposed on the inner side of the inner diameter of the cross roller bearing, and the articulated arm, the column, the moving mechanism, and the pedestal are swung and supported by the cross roller bearing. The base above the speed reducer is provided with a speed reducer cover so that the speed reducer is removed.

According to the first and second aspects of the present invention, the maintenance of the column, the arm attached to the column, and the pedestal for turning the hand is performed separately from the reduction gear when the built-in reduction gear is replaced. Since the pedestal is supported by the arranged bearings, it is not necessary to work by separately supporting the column, and maintenance can be easily performed.
In addition, useless space in the height direction of the pedestal can be removed. That is, the bottom surface of the hand part can be arranged as low as the pedestal, and the workpiece can be conveyed on the low pass line. That is, the bottom surface of the hand part can be arranged as low as the pedestal, and the workpiece can be conveyed on the low pass line.
In addition, even when a large moment is applied to the column, arm, or hand due to the pivoting of the pedestal, it is supported with a large turning radius using a bearing that can accurately hold loads from all directions, such as a cross roller bearing. As a result, it can be supported with high accuracy, and it is not necessary to support the column separately when taking out the reduction gear, and maintenance can be easily performed.

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

FIG. 1 is a perspective view of an articulated robot according to the present invention. FIG. 2 is a top view of the articulated robot of the present invention. FIG. 3 is a front view of the articulated robot of the present invention.
The articulated robot 1 of the present invention has a structure in which columns 12 divided into a plurality of blocks are connected to cope with an increase in the height of a stocker (not shown). In this way, the articulated robot 1 having a height corresponding to a high layer is formed by sequentially connecting the column blocks 16. In this embodiment, four column blocks 16 are connected. Both end surfaces of each column block 16 have a fitting structure so that the column blocks 16 are connected to each other, and further have positioning holes (not shown) for accurately arranging a guide mechanism including a linear guide, It is assembled by adjusting using a positioning jig.
Further, the articulated robot 1 of the present invention includes two sets of arms 2 that are rotatably connected by the joint portions 3, 4, and 5 and transmit a rotational force from a rotational drive source to perform a desired operation. Further, the hand portion 8 that holds the workpiece 9 by the arm 2 is configured to be linearly movable in the direction of taking out and supplying the workpiece 9 indicated by an arrow X in the drawing. Further, as shown in FIG. 2, the relationship between the rotation center axes of the proximal joint portions 3 provided in the two sets of arms 2 is the movement direction of the hand portion 8 with respect to the proximal joint portion 3 of the upper arm 21. The joint portion 3 at the base end of the lower arm 22 is arranged so as to be displaced.
Moreover, the vertical movement member 11 which moves the support member 10 with which the arm 2 is provided up and down is provided, and the vertical position of the arm 2 can be adjusted. The pedestal 13 of the vertical movement mechanism 11 is provided so as to be rotatable so that the articulated robot 1 can be turned to change its direction. Here, the vertical movement mechanism 11 is arranged in the same direction as the movement direction of the hand unit 8, and the support member 10 protrudes from the vertical drive mechanism 11 in a direction orthogonal to the movement direction of the hand unit 8, It is connected to the joint portion 3 at the end. Further, the support member 10 connected to the lower arm 22 is offset in the moving direction of the hand portion 8 as shown in FIG. 2 so as not to interfere with the pedestal 13 when the arm 2 is moved downward by the vertical movement mechanism 11. Form a shape. Further, the vertical movement mechanism 11 is covered with a protective cover having a shield function (not shown) to suppress dust generation from the inside of the column 12.
Next, the structure of the base 13 will be described with reference to FIG. A motor 31 that drives the pedestal 13 and a speed reduction mechanism 36 are included inside the pedestal 13. In order to reduce the thickness of the pedestal 13, ribs 51 are formed inside, and the structure is highly rigid so that the weight of the arm body attached to the column 12 can be held. The detailed structure of the base 13 will be described. The motor 31 is fixed to the pedestal 13 with bolts or the like, the output shaft 32 of the motor 31 is rotatably supported by a motor bearing 33, and one end of a belt 34 is attached to the output shaft 32. The other end of the belt 34 is attached to an input gear 36 that is rotatably supported by an input gear bearing 35 disposed immediately below the speed reducer cover 45, and the power of the motor 31 is applied to the input gear 36 via the belt 34. Communicated. The outer ring of the input gear bearing 35 is fixed to a bearing holding member 49, and the bearing holding component 49 is fastened to the output shaft 39 of the differential reduction gear 37. In this way, the bearing holding member 49 is fastened to the output shaft 39, and the output shaft 39 is also used as a mounting base for the bearing holding member 49, so that a useless space in the height direction of the pedestal can be removed. That is, the bottom surface of the hand part can be arranged as low as the pedestal, and the workpiece can be conveyed on the low pass line. The height from the differential reduction gear 37 to the reduction gear cover 45 is determined by the bearing thickness of the input gear bearing 35 and the width of the belt 34, and is the minimum dimension. Further, the input gear 36 is input to the differential reduction gear 37. The fixed portion 38 of the differential reducer 37 is fixed to the base 17, and the output shaft 39 of the differential reducer 37 is fixed to a fixing member 41 fixed to the base 13 by an output shaft fixing bolt 40. The height of the differential reduction gear 37 is determined by the bearing thickness of the differential reduction gear 37 and the input gear bearing 35 and the width of the belt 34, and is the minimum dimension.
Further, in order to reduce the thickness of the pedestal 13, it is not necessary to provide a multi-stage bearing for supporting the turning motion of the pedestal 13, and the cross roller bearing 42 is capable of holding loads from all directions. The inner ring of the cross roller bearing 42 is held by a fixing member 43 that is fixed to the pedestal 13 and supports the pedestal 13 in a freely rotatable manner. Further, the outer ring of the cross roller bearing 42 is held so as not to move by a fixing member 44 fixed to the base 17. In order to prevent vibration and falling of the column 12 during turning, the axial clearance of the cross roller bearing 42 is configured with a negative tolerance of about 0 to 15 μm, for example. By doing so, the axial clearance of the cross roller bearing becomes zero, so that the column 12 does not vibrate or fall.
The relationship between the cross roller bearing 42 and the differential reduction gear 37 will be described. When the rotation center of the input gear 36 of the differential reduction gear 37 is set as the turning center, the output shaft 39 of the differential reduction gear 37 has a rotation radius outside the rotation radius of the input gear 36 around the turning center. As shown, the output shaft 39 of the differential reduction gear 37 rotates. Further, the inner ring of the cross roller bearing 42 rotates so that the cross roller bearing 42 has a rotation radius outside the rotation radius of the output shaft 39 of the differential reduction gear 37 around the turning center. As described above, the cross roller bearing 42 and the differential reduction gear 37 have the same rotation center, and the cross roller bearing 42 is disposed so as to have a rotation radius outside the differential reduction gear 37. Further, the height direction is arranged such that the height of the fixing surface between the output shaft 39 of the differential reduction gear 37 and the fixing member 41 for fixing the base 13 is substantially the center of the height of the cross roller bearing 42. ing. In other words, by doing this, the moment load of the column, vertical movement mechanism, and vertical arm can be supported by a large cross roller bearing, and the height is approximately the height of the fixed surface of the output shaft and the cross roller bearing. By aligning the centers, twisting when the pedestal is driven is suppressed.
With such a configuration, the rotation support of the pedestal 13 is performed by the cross roller bearing 42, and the rotation of the pedestal 13 is performed by the output of the differential reduction gear 37, even when the reduction gear 37 is replaced, Since the base 13 is supported by the cross roller bearing 42, only the speed reducer 37 can be freely removed.
The present invention is different from Patent Document 1 in that the base end joint portion of the lower arm is arranged so as to be displaced in the movement direction of the hand portion with respect to the base end joint portion of the upper arm, and the pedestal The rotation support is performed by a cross roller bearing, and the pedestal is rotated by the output of the differential reducer.
In the present embodiment, the speed reducer has been described using a differential speed reducer. However, for example, a planetary speed reducer may be used.

Next, the operation will be described with reference to FIG. The two sets of arms 2 provided in the articulated robot 1 of the present invention have, for example, a plurality of joints, that is, the articulated robot 1 is configured as a horizontal articulated robot. The arm 2 in the present embodiment has a structure similar to that of the conventional arm 2.
The base end of the upper arm 6 is connected to the support member 10 via a drive shaft, and constitutes a rotatable shoulder joint 3. This shoulder joint 3 becomes the joint 3 at the base end of the arm 2. Further, the distal end of the upper arm 6 and the proximal end of the forearm 7 are connected via a drive shaft to constitute a rotatable elbow joint 4. Moreover, the front-end | tip of the forearm 7 and the hand part 8 are connected via the drive shaft, and the rotatable hand joint part 5 is comprised.
The arm 2 rotates the shoulder joint 3, the elbow joint 4, and the hand joint 5 by a rotation drive source (not shown), and moves the hand 8 in the workpiece take-out / supply direction. At this time, in the arm 2, due to the mechanism, the hand portion 8 faces in one direction, the extended position where the upper arm 6 and the forearm 7 are fully extended, and the contracted position where the upper arm 6 and the forearm 7 are folded. The telescopic movement is performed so as to move in a straight line.

Here, the turning radius of the articulated robot 1 of the present embodiment will be described using the lower arm 22. In the contracted position of the arm 22 shown in FIG. 5, the center of the work 9 held by the hand unit 8 is designed to coincide with the rotation center of the base 13. Further, the pedestal 13 is rotated by offsetting the rotation center of the shoulder joint portion 3, the rotation center of the hand joint portion 5, and the rotation center of the pedestal 13 so as to coincide with the axis of the movement direction of the hand portion 8. The turning radius of the articulated robot 1 can be reduced by preventing the elbow joint part 4 and the hand part 8 from protruding from the minimum area circle 15 required around the articulated robot 1 when performing the operation.
Here, in order to avoid complication of the drawing, the lower arm is used for explanation. Similarly, the upper arm 21 is designed so that the center of the workpiece 9 coincides with the rotation center of the base 13. The positional relationship of the rotation center of the shoulder joint part 3, the hand joint part 5, and the base 13 is also the same as that of the lower arm.
Next, the operation in the vertical direction will be described. The arm 2 is attached to the support member 10 and moves to the vertical movement mechanism 11 in the vertical direction according to a command from a controller (not shown). As shown in FIG. 3, since the support member 10 is offset in the moving direction of the hand 8 so that the support member 10 does not collide with the pedestal 13, the support member 10 is moved up and down 11. It is possible to descend to the lowermost point movement position.

Next, an example of the reduction gear replacement operation will be described with reference to FIG. First, the reduction gear cover 45 is removed by removing the cover bolt 46. If it does so, the fixing member 41 fixed to the bearing 35 for input gears and the base 13 can be confirmed. Next, the fixing bolt 47 of the input gear 36 is pulled out, and the input gear 36 and the belt portion are separated. The belt 34 is removed by doing so. Next, the output shaft fixing bolt 40 is removed, and the fixing member 41 fixed to the base 13 is removed. By doing so, the output shaft 39 of the differential gear machine 37 can be freely taken out. Next, the fixing portion bolt 48 that fastens the fixing portion 38 of the differential gear reducer 37 is removed, and the fixing portion 38 of the differential gear reducer 37 is removed from the base 17. In this way, the differential gear reducer 37 can be taken out from the base 13 freely.
As described above, the differential gear reducer can be taken out. At this time, since the pedestal is supported by the cross roller bearing, the column and the vertical movement mechanism attached to the pedestal can be operated without providing a special instrument.
In addition, the motor can be easily replaced by removing the cover arranged on the upper part of the motor.

The perspective view of the articulated robot which shows the Example of this invention Top view of an articulated robot showing an embodiment of the present invention Front view of an articulated robot showing an embodiment of the present invention Side sectional view of a pedestal showing an embodiment of the present invention The figure which shows the turning radius of the articulated robot which shows the Example of this invention Perspective view of a conventional articulated robot The figure which shows the turning radius of the conventional articulated robot Front view showing the turning structure of a conventional articulated robot

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Articulated robot 2 Arm 21 Upper arm 22 Lower arm 3 Shoulder joint part 4 Elbow joint part 5 Hand joint part 6 Upper arm 7 Forearm 8 Hand part 9 Work 10 Support member 11 Vertical movement mechanism 12 Column 13 Base 14 Base 15 Minimum area Circle 16 Column block 17 Base 31 Motor 32 Output shaft 33 Motor bearing 34 Belt 35 Input gear bearing 36 Input gear 37 Differential reduction gear 38 Fixed portion 39 Output shaft 40 Output shaft fixing bolt 41 Fixing member 42 Cross roller bearing 43 Fixed Member 44 fixing member 45 speed reducer cover 46 cover bolt 47 fixing bolt 48 fixing portion bolt 49 bearing holding member 50 opening 51 rib

Claims (2)

A hand unit for placing a transported object, and a hand unit connected to the hand unit, including at least two or more rotary joints, arranged to expand and contract so as to move the hand unit in one direction, and to face each other in the vertical direction. An articulated arm, a moving mechanism attached to the column so as to move up and down, a support member for connecting the moving mechanism and the articulated arm, and a pedestal at the lower end of the column with respect to the column. In a multi-joint robot configured such that a swivel axis is connected to be offset so as to be orthogonal to the moving direction of the hand and the direction in which the multi-joint arm moves up and down,
Having a first fixing member for fixing the said output shaft of the reduction gear for pivoting said pedestal pedestal, fixing surface of the output shaft of the reduction gear and the first securing member, the pivoting of the seat It is located between the thicknesses of the cross roller bearings that support the pedestal arranged on the outer side with respect to the radial direction of the speed reducer with the shaft as the center, and the outer ring of the cross roller bearing is arranged on the base fixed to the base An articulated robot characterized by being fixed to a second fixing member. The speed reducer is disposed inside the inner diameter of the cross roller bearing, and the speed reducer is removed with the articulated arm, the column, the moving mechanism, and the pedestal supported by the cross roller bearing. The articulated robot according to claim 1, wherein a reducer cover is provided on the base above the reducer.