JPH03104591A - Robot hand with three rotation axes - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] A. INDUSTRIAL APPLICATION FIELD The present invention relates to a robot hand that is rotatable around three rotation axes, and is particularly aimed at miniaturization. B. Conventional technology and its problems Robot hands having three rotating axes have been known for some time, but each of them has the problem that each rotating axis is supported by a separate member, making it difficult to miniaturize. Ta. A technical problem of the present invention is to miniaturize a robot hand having three rotation axes.

C. The present invention will be explained in conjunction with FIGS. 1 and 4 showing an embodiment of means for solving the problem.
This is applied to a robot hand 230 that can rotate A around three rotation axes A to C.

The above object is achieved with the following configuration.

A double trunnion 233 that rotatably supports the hand portion HA around the first axis C, and this double trunnion 233
an arm portion 203 rotatably supported around a second axis B perpendicular to the first axis; and an arm portion 203 rotatably supported around a third axis A perpendicular to the first and second axes. A fixed part 202 that supports the fixed part 202, a first drive means 242 that is installed inside the double trunnion 233 and outputs a rotational force about the first axis C that is transmitted to the hand part HA, and a double trunnion 233 that is installed in the fixed part 202. a second drive means 224 that outputs a rotational force about the second rotation axis B to be transmitted to the fixed part 202;
A third related means 222 is installed in the arm section 203 and outputs a rotational force about the third axis A to be transmitted to the arm section 203.

D. The working hand portion HA rotates around the first to third axes C, B, and A to obtain a desired posture. Since the first driving means 242 for rotating the hand portion HA around the first axis C is installed inside the double trunnion 233, the robot hand is miniaturized. In the above sections C and D explaining the structure of the present invention, figures of embodiments are used to make the present invention easier to understand, but the present invention is not limited to the embodiments.

E. Embodiment FIGS. 1 to 6 are explanatory diagrams in which the present invention is applied to a robot hand of a Cartesian coordinate robot for can assembly.

FIG. 2 is a schematic diagram showing the degree of freedom of a can assembly Cartesian coordinate robot. The Cartesian coordinate robot 20 is mounted on a traveling frame 10 and is movable in the ．． It is rotatable around the B and C axes. A welding robot 90 is provided integrally with the Cartesian coordinate robot 20, and is rotatable around a-e axes and has a welding gun 9 at its tip.
It is equipped with l.

FIG. 3 is a diagram showing the overall structure of the Cartesian coordinate robot 2o mounted on the traveling frame 10. The traveling frame 10 has six pillars 11
A to 11f (1↓d to 11f are not shown) are erected from the floor surface, and a horizontal rack 1 is provided with a rail 12 for running in the X direction.
5 and a vertical frame 16 are supported by supports 11a to llf. A running body 13 is installed on this horizontal frame 15 so as to be able to run in the X-axis direction along the X-direction running rail 12, and a rail 14 extending in the Y-axis direction is installed on this running body 13. ．． The running body 13 has the above-mentioned Cartesian coordinate robot 2.
0 is installed so that it can run along the rail 14 in the Y-axis direction. Cartesian coordinate robot 2 with reference to the engineering drawing, figure 4, and figure 5.
0 will be explained in detail. FIG. 1 is a perspective view of the hand 230 of the Cartesian coordinate robot 20 seen from below, FIG. 4 is a perspective view of the upper part of the Cartesian coordinate robot 20 seen from diagonally above in the ■ direction of FIG. 3, and FIG. FIG. 3 is a perspective view of the upper part of the Cartesian coordinate robot 20, viewed diagonally from above in the direction ◯ in FIG. 3. As shown in Figures 4 and 5, the Cartesian coordinate robot 2
0 is a robot body 20 shaped as a rectangular frame.
1, and a rectangular tube 20 provided on this main body 201 so that it can be raised and lowered.
2, and a rotary tube 20 inserted into this rectangular tube 202 and rotatably supported via a bearing (not shown).
3. A Z-axis movement drive device 204 is installed in the robot body 201. This Z-axis translation gear M
Reference numeral 204 reduces the output of a motor (not shown) with a worm reducer (not shown), and further reduces the speed with spur gears 204a, 204b to obtain rotational output from a pinion 204c. This pinion 204c meshes with a rack 205 extending in the axial direction on the side surface of the rectangular tube 202, and the rectangular tube 202 is moved up and down in the Z-axis direction by the Z-axis moving drive device 204. As shown in FIG. 4, two linear bearing rails 206 are installed in the square tube 202 to extend in the axial direction.
6 is guided by a linear bearing 207 fixed to the robot body 201.

Furthermore, a pair of pneumatic cylinders 209 are installed on a mounting bracket 208 fixed to the robot body 201. The piston rods of each pneumatic cylinder 209 are connected to each other by a shaft 210, and a sprocket 211 is rotatably provided on the shaft 210. This sprocket 211 has a chain 21 which has one end 213a connected to the bracket 208 and the other end 213b connected to the bracket 212 of the square tube 202.
3 is being passed around. Therefore, when compressed air is introduced into the pair of pneumatic cylinders 209 to extend the piston rod, the weight of the robot arm (also referred to as a Z-axis arm) that is restrained from the square tube 202 can be canceled.

As shown in FIG. 4, a gear 221 is provided at the upper end of the rotary tube 203 rotatably supported by the square tube 202.
This gear 221 meshes with an output gear 222a of an A-axis rotation drive device 222 fixed to the rectangular tube 202. Therefore, the active device 222 for rotating the A-axis rotates the rotary cylinder 20.
3 rotates around the A axis. A B-axis rotating translation device 224 is installed on the gear 221 via a bracket 223. A chain 225 is wound around a sprocket 224a attached to this output shaft, and a robot hand 230, which will be described later, rotates around the B axis in FIG. 1 via this chain 225. chain 2
25 extends downward through an opening 223a formed in the bracket 223 and an opening 221a formed in the gear 221.

As shown in FIG. 1, a pair of vertical walls 231 and 232 are erected at the lower end of the rotary cylinder 203.
A double trunnion 233 is rotatably supported by shafts 233a and 233b. The shafts 233a, 233b are bearings 234A, 23 provided on the vertical walls 231, 232.
4B, and a gear 235 is attached to the tip of the shaft 233a so as to rotate together with the shaft 233a. The gear 235 has
A gear 236 that rotates together with a sprocket 237 meshes with the sprocket 237, and the aforementioned chain 225 is passed around the sprocket 237. Therefore, double trunnion 233
is rotated around shafts 233a and 233b via a chain 225 by a translation device 224 for B-axis rotation. Furthermore, in FIG. 1, 238 is a pair of vertical walls 238a.
, 238b, and the vertical walls 238a, 238b are double trunnions 233.
The double trunnion 233 is rotatably supported by shafts 239A and 239B. Shaft 239A, 2
39B is supported by bearings 240A and 240B mounted on vertical walls 238a and 238b, respectively.

A ring gear 241 cut at an angle of 90 degrees is fixed to the inner surface of the vertical wall 238b, and an output gear 242a of a C-axis rotation drive device 242 meshes with this ring gear 241. This movable device 242 is screwed with its mounting surface 242b in contact with an unillustrated upper plate of the double trunnion 233. Therefore, this C-axis rotation drive device 242
Due to the rotation of the bracket 238, the shafts 239A, 239B
rotate around.

On the lower surface of the bracket 238, a hydraulic cylinder 243 for clamping, which constitutes the hand portion HA, is fixedly installed.
A fixed gripping plate 245 that grips the workpiece with a movable gripping plate 244 attached to the piston rod of the hydraulic cylinder 243.
is fixed.

FIG. 6 shows a pneumatic circuit of a Z-axis balancer device that cancels the weight of a certain robot arm from a square tube 202 or the like. The Z-axis balancer device is composed of the above-mentioned pneumatic cylinders 209, etc., and is connected to a pair of pneumatic cylinders 2 in the pneumatic circuit shown in FIG.
By adjusting the thrust of 09, the workpiece pressing force by the Z-axis arm is controlled. In FIG. 6, low-pressure compressed air is supplied from an air source installed in the factory through an air dryer 61 and a filter 62 to a boosting compressor 63, where it is boosted to a required pressure and stored in an air tank 64.

The air tank 64 has an air regulator 65 and an electromagnetic shut-off valve 6.
6 to the pair of pneumatic cylinders 209 described above. In addition, a mist separator 67 is provided in the air tank 64.
A proportional electromagnetic regulator 68 is connected through the port, and a secondary port of the proportional electromagnetic regulator 68 is connected to a control port of the air regulator 65. Since the secondary pressure of the proportional electromagnetic regulator 68 is proportional to the applied voltage, the III control pressure of the air regulator 65 is controlled by the voltage applied to the proportional electromagnetic regulator 68.

The operation of the can-assembling Cartesian coordinate robot 20 constructed in this way will be explained.

The traveling body 13 is moved in the X-axis direction and the Cartesian coordinate robot 20 is moved in the Y-axis direction to position the robot hand 230 above the workpiece. At this time, the maximum voltage is applied to the proportional electromagnetic regulator 68 of the Z-axis balancer device to maximize the control pressure by the air regulator 65. As a result, the dead weight of the Z-axis arm of the Cartesian coordinate robot 20 is substantially canceled by the thrust of the pneumatic cylinder 209, and the Z-axis arm is held at an arbitrary position by the rotational resistance of the Z-axis moving drive unit W204. In this state, the parking device for Z-axis movement 2
04, the rectangular tube 202 constituting the Z-axis arm is lowered to a predetermined position. Furthermore, the A-axis rotation driving device 222
The robot hand 230 rotates the rotary tube 203 by
The hand portion HA of is controlled to a predetermined posture around A#. Further, the double trunnion 233 is rotated by the B-axis rotation drive device 224 via the chain 225, and the hand portion HAtI of the robot hand 230 is controlled to a predetermined posture around the B-axis. Furthermore, the robot hand mounting bracket 238 is rotated by the C-axis rotation parking device 242 to hold the hand portion HA of the robot hand 230 in an arbitrary posture around the C-axis. In this way, the robot hand 230
are moved around A, B, and C@ to position the workpiece between the movable gripping plate 244 and the fixed gripping plate 245 of the telescopic cylinder 243, and the piston rod of the telescopic cylinder 243 is advanced to grip the workpiece.

Thereafter, the square tube 202 is raised by the Z-axis moving rotation device 204 and moved in the X- and Y-axis directions to transport the workpiece to the welding point.

A workpiece to be welded (hereinafter referred to as the fixed workpiece) is placed in advance at the welding point, and the transported workpiece (hereinafter referred to as the transported workpiece) is positioned at the welding position of the fixed workpiece. This positioning consists of X, Y, Z, A, B, C
This is done by controlling the position of the robot arm 230 about six axes. After the positioning is completed, the voltage applied to the proportional electromagnetic regulator 68 of the Z-axis balancer device is lowered in order to press the conveyed workpiece against the fixed workpiece with a desired pressing force. As a result, the thrust of the pneumatic cylinder 209 decreases, and a force obtained by subtracting the upward force due to the thrust from the weight of the Z-axis arm acts on the fixed workpiece.

This completes the setup for welding the transported workpiece to the fixed workpiece, and then the transported workpiece is welded to the fixed workpiece by the welding gun 91 of the welding robot 90 attached to the rectangular tube 202, which is a biaxial arm. After welding is completed, the maximum voltage is applied to the proportional electromagnetic regulator 68 to maximize the pressure supplied to the pneumatic cylinder 209, and the Z-axis arm is raised to lift the workpiece, and the Cartesian coordinate robot 20 is moved in the X and Y-axis directions. is moved to transport the workpiece to a predetermined location, the Z-axis arm is lowered and the workpiece is placed at the predetermined location, and the series of operations is completed.

The pressing force of the conveyed workpiece against the fixed workpiece can be arbitrarily set by adjusting the secondary pressure of the proportional electromagnetic regulator 68 of the Z-axis balancer device. Furthermore, since the weight of the Z-axis arm is canceled by the thrust of the pneumatic cylinder 209 of the two-axis balancer device, the capacity of the Z-axis moving drive device 204 can be small, resulting in cost reduction and compactness.

In the configuration of the above embodiment, the C axis serves as the first axis, the B axis serves as the second axis, the A axis serves as the third axis, the rotating tube 202 serves as the arm portion, and the square tube 202 serves as the fixed portion. , C-axis rotation drive device 242
is the first heel movement means, and the B-axis rotation drive device 224 is the second heel movement means.
The A-axis rotation drive device 222 constitutes the active means and the third swinging means, respectively.

Note that the robot hand according to the present invention is not limited to the structure of the embodiment. Further, although the case where the present invention is applied to a rectangular coordinate robot for can assembly has been described, the type and use of the robot are not limited in any way.

F. Effects of the Invention According to the present invention, since a double trunnion structure is adopted and the cantering means for rotating the first axis is internally provided therein, it is possible to miniaturize the robot hand capable of rotating three axes. Become.

[Brief explanation of drawings]

Figures 1 to 6 illustrate one embodiment of the present invention.
Fig. 1 is an exploded perspective view of the robot hand seen from below, Fig. 2 is a schematic diagram illustrating the 6-axis motion of the robot hand, and Fig. 3 is a diagram showing the robot hand according to the present invention as a rectangular coordinate robot 20 for can assembly. The overall structure when applied, Figure 4 is Z
Figure 5 is a partially exploded perspective view of the axis arm viewed from above in direction ■ in Figure 3, and Figure 5 is a partially exploded perspective view of the Z-axis arm viewed from above in direction ■ in Figure 3. The perspective view and FIG. 6 are pneumatic circuit diagrams of the Z-axis balancer device. 10: Travel frame 20: Cartesian coordinate robot 65: Air regulator 68: Proportional electromagnetic regulator 90: Welding robot 201: Robot body 202: Square tube 203: Rotating tube 204: Z-axis movement drive device II 205: Rack 206: Linear Bearing guide rail 2o7: Linear bearing 209: Pneumatic cylinder 210: Rotating connecting shaft 21: Sprocket 2l3: Chain 222: Rotating device for A-axis rotation 224: Parking device for B-axis rotation 225: Chain 23o: Robot hand 231 ，
232: Standing wall 233: Double trunnion 233a, . 233b: B-axis rotating shaft 235, 236: Housing 237: Sprocket 238: Robot hand mounting bracket 239A,
239B: C-axis rotating shaft 242: Active device for C-axis rotation

Claims (1)

[Scope of Claim] A robot hand capable of rotating a hand portion that grips a workpiece around three rotation axes, including a double trunnion that supports the hand portion rotatably around a first axis; an arm rotatably supported around a second axis perpendicular to the axis of the first and second axes; a fixed part rotatably supported the arm around a third axis perpendicular to the first and second axes; a first drive means that is installed inside the double trunnion and outputs a rotational force about the first axis that is transmitted to the hand section;
a second drive means that outputs a rotational force about the rotational axis of the arm; and a third drive means that is installed on the fixed part and outputs a rotational force about the third rotational axis that is transmitted to the arm. robot hand.