JP3924525B2 - Industrial robot - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an industrial robot. More specifically, the present invention relates to a lifting mechanism for an industrial robot.
[0002]
[Prior art]
As this type of robot, for example, there is an arm drive device having a hand that can be moved up and down to place a workpiece such as a semiconductor wafer or a liquid crystal panel. As the lifting mechanism of such a hand, as shown in FIG. 6, for example, three upper and lower cylindrical frames 101 to 103 that can be raised and lowered in a concentric manner, and an end portion 1 of the middle frame 102 are directly moved up and down. One ball screw driving means 104, a moving pulley 105 provided on the upper part of the middle frame 102, and a belt 106 wound around the moving pulley 105 to connect the lower frame 103 and the upper frame 101 to each other. And a movable pulley drive means 107 (see Japanese Patent No. 2998501). A hand is provided on the upper frame 101. Each of the frames 101 to 103 is supported by a linear guide so as to be movable up and down.
[0003]
In this elevating mechanism, the middle frame 102 is raised and lowered by the operation of the ball screw driving means 104. At this time, the movable pulley 105 raises and lowers the belt 106, and accordingly, the upper frame 101 is raised and lowered. Thereby, the height of the hand can be changed.
[0004]
[Patent Document 1]
Japanese Patent No. 2998501 [0005]
[Problems to be solved by the invention]
However, in the industrial robot described above, since both the ball screw driving means 104 and the moving pulley driving means 107 are provided only at one end portion of the frames 101 to 103, the load for pushing up the frames 101 to 103 from below. A point and the load point applied from the top will shift | deviate, the moment in each frame 101-103 may become large, and smooth raising / lowering may be inhibited. In particular, in recent years, it has been desired to increase the lifting width with an increase in the size of the workpiece. On the other hand, the moment to the lifting mechanism has further increased due to the weight of the workpiece. In order to smoothly move up and down, it is conceivable to increase the rated load of the linear guide or increase the guide span, but this increases the overall height.
[0006]
In addition, it is conceivable to attach the ball screw driving means 104 to the center of the frames 101 to 103 so as to suppress the moment of the frames 101 to 103, but this eliminates the space for wiring and the like, so that other parts can be controlled. It will disappear or become very difficult to maintain.
[0007]
Further, since this industrial robot uses only one moving pulley drive means 107, the upper frame 101 may easily fall if the belt 106 is cut.
[0008]
Accordingly, an object of the present invention is to provide an industrial robot that can suppress the generation of moments in each frame that moves up and down while keeping the overall height low, and can prevent the frame from falling.
[0009]
[Means for Solving the Problems]
In order to achieve such an object, the invention described in claim 1 is composed of a frame that is divided into a plurality of stages from the lower end to the upper end and moves up and down along the lifting guide shaft, and each frame has a lifting means. An extended state in which the frame is continuously connected in the lifting guide axis direction and the upper end extends upward with respect to the lower end; and a contracted state in which the frame overlaps with the lifting guide axis direction and the upper end is contracted downward and approaches the lower end. In the industrial robot that can extend and contract as a whole, the lifting means is composed of two lifting means provided at symmetrical positions with the center line in the lifting direction passing through the center of gravity of the frame as the axis of symmetry. Yes. Here, in this specification, the “symmetrical position” is a concept including not only exact symmetry but also a state close thereto.
[0010]
Accordingly, since the two lifting means are arranged with the center line of the frame as the axis of symmetry, the frame is supported symmetrically with respect to the center of gravity and is lifted up and down with a good balance between the left and right. As a result, it is possible to suppress the moment from being generated in the frame, and it is possible to smoothly move up and down. For this reason, the load of the linear guide that supports the frame is reduced, and the linear guide can be reduced in size and the guide span can be shortened. Therefore, the overall height can be reduced.
[0011]
In addition, since two lifting means are provided, even if one lifting means fails, the other lifting means operates. Therefore, as compared with the case the lifting means there is only one, it is possible to halve the probability of frame dropping due to the failure of the lifting means.
[0012]
According to a second aspect of the present invention, in the industrial robot according to the first aspect, the elevating guide shaft is provided at a position symmetrical to the center line of the frame. Therefore, the left / right balance of the frame is improved.
[0013]
Furthermore, the invention according to claim 3 is the industrial robot according to claim 1 or 2, wherein the two lifting means provided on the lowermost frame use a ball screw driving means using a ball screw and a piston cylinder mechanism. Piston drive means.
[0014]
Therefore, there is no need to synchronize both screws and adjust the timing as in the case of using two ball screw driving means, so that the adjustment work at the initial setting can be easily performed. The piston cylinder mechanism is less expensive than the ball screw driving means, and the piston cylinder mechanism consumes almost no power when stopped, so the running cost is lower than the ball screw driving means. The cost can be reduced as compared with the case of using the means.
[0015]
According to a fourth aspect of the present invention, in the industrial robot according to any one of the first to third aspects, the lifting means provided on the frame excluding the lowermost frame is a moving pulley lifting / lowering means using a moving pulley. It is made to become. Therefore, as a driving force for lifting, all the frames can be lifted / lowered using only the lifting / lowering means provided in the lowermost frame.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings.
[0017]
1 to 5 show an example of an embodiment of the industrial robot 1 of the present invention. This industrial robot 1 is composed of frames 3, 4 and 5 which are divided into a plurality of stages from the lower end to the upper end and which are moved up and down along the lifting guide shaft 2, and are moved up and down in each of the frames 3, 4 and 5. Means 6, 7 and 8 are provided. Further, the industrial robot 1 is in an extended state in which the frames 3, 4 and 5 are continuously connected in the direction of the lifting guide shaft 2 and the upper end extends upward with respect to the lower end (indicated by a two-dot chain line in FIG. 4). And a frame 3, 4, 5 that overlaps in the direction of the lifting guide shaft 2, and can be expanded and contracted as a whole (shown by a solid line in FIG. 4). It is. In such an industrial robot 1, the lifting means 6, 7, 8 are configured by two lifting means provided at symmetrical positions with the center line of the frames 3, 4, 5 as the symmetry axis. . For this reason, since the two elevating means are arranged with the center line of the frames 3, 4, 5 as the axis of symmetry, the frames 3, 4, 5 are raised / lowered with a good balance between left and right. Therefore, it is possible to suppress the moments from being generated in the frames 3, 4, 5, so that the ascending and descending can be performed smoothly. In addition, since two lifting means are provided, even if one lifting means fails, the other lifting means operates. Therefore, the probability that the frames 3, 4 and 5 are dropped due to the lifting means failure is minimized. Can be lowered.
[0018]
The industrial robot 1 is, for example, an arm driving device that transports the workpiece 13 from a cassette to a manufacturing apparatus. That is, the industrial robot 1 includes an arm 11 supported by the lifting mechanism 10 in addition to the lifting mechanism 10 having the frames 3, 4, 5 and the lifting means 6, 7, 8. And a hand 12 attached to the tip. The frames 3, 4, and 5 include a base 14, a lower frame 3, a middle frame 4, and an upper frame 5. The lower frame 3 is supported with respect to the base 14, the middle frame 4 with respect to the lower frame 3, and the upper frame 5 with respect to the middle frame 4 so as to be lifted and lowered by the lifting guide shaft 2. The arm 11 moves up and down together with the upper frame 5. Reference numeral 15 in the figure denotes a cover that hides the frames 3, 4, and 5 from the side. 4 and 5, reference numeral 26 denotes a rail for moving the industrial robot 1.
[0019]
Each lifting guide shaft 2 is provided at a symmetrical position with respect to the center line of the frames 3, 4, 5. For this reason, the right and left balance of the frames 3, 4, 5 is improved. The elevating guide shaft 2 includes a guide rail 16 provided along the vertical direction of the frames 3, 4, and 5, and a slider 17 provided to be slidable with respect to the guide rail 16. A guide rail 16 is attached to one of the two relatively moving frames, and a slider 17 is attached to the other.
[0020]
The lifting means 6, 7, and 8 are a lower lifting means 6 that lifts and lowers the lower frame 3 relative to the base 14, a middle lifting and lowering means 7 that lifts and lowers the middle frame 4 relative to the lower frame 3, and the middle frame 4. And an upper elevating means 8 for elevating and lowering the upper frame 5.
[0021]
The lower elevating / lowering means 6 includes a ball screw driving means 18 using a ball screw and a piston driving means 19 using a piston cylinder mechanism. For this reason, there is no need to synchronize both screws and adjust the timing as in the case of using two ball screw driving means, so that the adjustment work at the initial setting can be easily performed. The ball screw driving means 18 and the piston driving means 19 support the load on the upper side of the lower frame 3 by half.
[0022]
Here, since the ball screw driving means 18 and the piston driving means 19 are arranged as units at the left and right ends of the lower frame 3, maintenance such as replacement at the time of failure is easier than in the case where they are arranged at the center. Can be done.
[0023]
The ball screw driving means 18 includes a motor 20, a ball screw 21 having a longitudinal direction as a longitudinal direction, a slider 22 fixed to the lower portion of the lower frame 3, and a slider 22 that moves up and down with the ball screw 21. A belt 23 and a pulley 24 that transmit the rotation to the ball screw 21 are provided. The rotation of the motor 20 is transmitted to the ball screw 21 via the belt 23 and the pulley 24. As the ball screw 21 rotates, the slider 22 moves up and down to raise and lower the lower frame 3. The piston driving means 19 is called a balancer cylinder and includes an air cylinder 25 and a piston. The tip of the piston rod 27 is fixed to the upper part of the lower frame 3. The piston moves up and down by taking compressed air into and out of the air cylinder 25 from the outside.
[0024]
The middle elevating / lowering means 7 and the upper elevating / lowering means 8 are constituted by a moving pulley elevating means using a moving pulley. For this reason, all the frames 3, 4, and 5 can be lifted / lowered using only the lifting / lowering means 6 provided in the lower frame 3 as a driving force for the lifting / lowering.
[0025]
The middle elevating means 7 includes a pulley 28 attached to the upper and lower portions of the lower frame 3, a timing belt 29 stretched over both pulleys 28, and an upper portion of the belt 29 when the lower frame 3 is at the lowest position. A first connection member 30 that connects the base 14 and a second connection that connects the lower part of the belt 29 opposite to the first connection member 30 and the middle frame 4 when the lower frame 3 is in the lowest position. Member 31. Since the middle elevating means 7 is provided on each of the left and right sides, even if one timing belt 29 is completely removed, the middle frame 4 is supported by the other timing belt 29 and the fall is prevented.
[0026]
The upper lifting / lowering means 8 includes a pulley 32 attached to the upper and lower portions of the middle frame 4, a timing belt 33 stretched over both pulleys 32, and an upper portion of the belt 33 when the middle frame 4 is at the lowest position. A third connection member 34 that connects the lower frame 3 and a fourth connection that connects the lower portion of the belt 33 opposite to the third connection member 34 and the upper frame 5 when the middle frame 4 is in the lowest position. And a member 35. Since the upper elevating means 8 is provided on each of the left and right sides, even if one timing belt 33 is completely removed, the upper frame 5 is supported by the other timing belt 33 and the fall is prevented.
[0027]
The operation of the industrial robot 1 described above will be described below.
[0028]
When the driving of the motor 20 of the ball screw driving means 18 and the feeding of compressed air to the piston driving means 19 are performed in the state where the elevating mechanism 10 is most contracted, the lower frame 3 is raised. As a result, both pulleys 28 of the middle elevating means 7 are raised. Since the upper part of the belt 29 and the base 14 are connected by the first connecting member 30, the member 31 is raised by the lower frame 3 and the pulleys 28 being raised.
[0029]
At this time, the middle frame 4 is raised with respect to the lower frame 3 via the second connecting member 31. Thereby, both the pulleys 32 of the upper raising / lowering means 8 raise. Since the upper part of the belt 33 and the lower frame 3 are connected by the third connecting member 34, the member 35 is raised by raising the middle frame 4 and both pulleys 32.
[0030]
At this time, the upper frame 5 is raised with respect to the middle frame 4 via the fourth connecting member 35. Thus, the arm 11 and the hand 12 provided on the upper frame 5 are raised to a predetermined height.
[0031]
Further, when the height of the arm 11 and the hand 12 is lowered, the motor 20 of the ball screw driving means 18 is rotated in the reverse direction and the compressed air is discharged from the piston driving means 19. At this time, the pressure is controlled by a regulator (not shown) so that the air pressure of the air cylinder 25 is constant. As a result, the lower frame 3 is lowered, and both pulleys 28 of the middle elevating means 7 are lowered. Since the belt 29 and the base 14 are connected by the first connecting member 30, the member 31 is lowered by the lower frame 3 and the pulleys 28 being lowered.
[0032]
At this time, the middle frame 4 is lowered with respect to the lower frame 3 via the second connecting member 31. Thereby, both the pulleys 32 of the upper raising / lowering means 8 descend | fall. Since the belt 33 and the lower frame 3 are connected by the third connecting member 34, the member 35 is lowered by the lowering of the middle frame 4 and both pulleys 32.
[0033]
At this time, the upper frame 5 is lowered with respect to the middle frame 4 via the fourth connecting member 35. Thus, the arm 11 and the hand 12 provided on the upper frame 5 are lowered to a predetermined height.
[0034]
The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the present embodiment, the elevating means 6 provided on the lower frame 3 is composed of a ball screw driving means 18 and a piston driving means 19, but the invention is not limited to this, and both are composed of the ball screw driving means 18. You may do it. Also in this case, the moment can be prevented from being generated in the frame 3, so that the ascending and descending can be performed smoothly.
[0035]
In this embodiment, timing belts are used as the belts 29 and 33 of the movable pulley lifting / lowering means, but the present invention is not limited to this, and steel belts or chains may be used. Alternatively, in the present embodiment, the pulleys 28 and 32 and the belts 29 and 33 are used, but the present invention is not limited to this, and a combination of a rack and a pinion may be used.
[0036]
Furthermore, in this embodiment, a cylinder piston mechanism that is operated by compressed air is used as the piston driving means 19, but the present invention is not limited to this, and hydraulic pressure may be used.
[0037]
In this embodiment, the industrial robot 1 is an arm drive device, but is not limited to this, and may be another device such as a processing machine.
[0038]
【The invention's effect】
As is clear from the above description, according to the industrial robot of the first aspect, since the two lifting means are arranged with the center line of the frame as the axis of symmetry, the frame is supported symmetrically with respect to the center of gravity. It is lifted up and down with a good balance between left and right. As a result, it is possible to suppress the moment from being generated in the frame, and it is possible to smoothly move up and down. Therefore, the linear guide that supports the frame can be reduced in size and the guide span can be shortened, so that the overall height can be reduced. In addition, since the structure can be reduced in size, the weight of the industrial robot can be reduced.
[0039]
In addition, since two lifting means are provided, even if one lifting means fails, the other lifting means operates. Therefore, as compared with the case the lifting means there is only one, it is possible to halve the probability of frame dropping due to the failure of the lifting means.
[0040]
Further, since the elevating means is disposed at both the left and right ends of the frame, maintenance such as replacement can be easily performed as compared with the case where it is disposed at the center.
[0041]
According to the industrial robot of the second aspect, since the lifting guide shaft is provided at a symmetrical position with respect to the center line of the frame, the left and right balance of the frame is improved.
[0042]
Further, according to the industrial robot of the third aspect, since the elevating means provided in the lowermost frame is composed of the ball screw driving means and the piston driving means, as in the case of using two ball screw driving means. There is no need to synchronize both screws and the timing can be adjusted, and adjustment work at the initial setting can be easily performed. The piston cylinder mechanism is less expensive than the ball screw driving means, and the piston cylinder mechanism consumes almost no power when stopped, so the running cost is lower than the ball screw driving means. The cost can be reduced as compared with the case of using the means.
[0043]
According to the industrial robot of claim 4, since the lifting means provided on the frame excluding the lowermost frame is composed of a moving pulley lifting means using a moving pulley, the lowermost frame is used as a driving force for lifting. All the frames can be lifted / lowered using only the lifting / lowering means.
[Brief description of the drawings]
FIG. 1 is a plan view showing a lifting mechanism of an industrial robot according to the present invention.
FIG. 2 is a front view showing a lower raising / lowering means of a lifting mechanism for an industrial robot.
FIG. 3 is a front view showing middle lifting means and upper lifting means for a lifting mechanism of an industrial robot.
FIG. 4 is a front view showing an industrial robot.
FIG. 5 is a plan view showing an industrial robot.
FIG. 6 is a vertical front view showing a lifting mechanism of a conventional industrial robot.
[Explanation of symbols]
1 Industrial robot 2 Lifting guide shaft 3 Lower frame (lowermost frame)
4 Middle frame
5 Upper frame (frame)
6 Lower elevating means (elevating means)
7 Middle lifting / lowering means (lifting / lowering means)
8 Lifting means (lifting means)
18 Ball screw drive means 19 Piston drive means 21 Ball screw

Claims (4)

The frame is divided into a plurality of stages from the lower end to the upper end and is moved up and down along the lifting guide shaft, and each of the frames is provided with lifting means, and the frame is continuously provided in the lifting guide shaft direction. An industry that can expand and contract as a whole between a stretched state in which the upper end extends upward relative to the lower end and a contracted state in which the frame overlaps the lifting guide shaft direction and the upper end contracts downward and approaches the lower end. The industrial robot according to claim 1, wherein the elevating means comprises two elevating means provided at symmetrical positions with a center line in the elevating direction passing through the center of gravity of the frame as an axis of symmetry. Industrial robot according to claim 1, wherein the elevating guide shaft, characterized in that provided in symmetrical positions with respect to the center line of the frame. 3. The industry according to claim 1, wherein the two lifting means provided on the lowermost frame are composed of a ball screw driving means using a ball screw and a piston driving means using a piston cylinder mechanism. Robot. The industrial robot according to any one of claims 1 to 3, wherein the lifting means provided on the frame excluding the lowermost frame comprises a moving pulley lifting means using a moving pulley.

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