JPS5810487A - Hand for robot - 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 The present invention relates to a hand for grasping a workpiece in an industrial robot or the like, and particularly to a gripping hand having a function of accurately holding the grasping position even for workpieces of different dimensions.

Conventionally, with a node that grasps a workpiece with a circular cross section of M, a machine tool that can grasp workpieces of different dimensions and keep the workpiece spindle always at a constant position with respect to the hand has been used, especially for machine tools such as lathes. Important in /S link robots for loading and unloading workpieces.

Many of these hands generally have about three fingers, and these fingers move concentrically with each other to grasp the workpiece as described above. As a means for moving the fingers concentrically, a mechanism constituted by mechanical elements such as a gear train and a pole screw is used.

The mechanism described above is used not only because it can be constructed at a lower cost than when each phase is equipped with its own drive mechanism, but also because the amount of movement of each phase can be controlled mechanically. This is because it can be done centrally. However, in the mechanism described in #, (1) the elements that make up the mechanism are crystal forces! (2) Due to the use of gears, accuracy is inevitably reduced due to effects such as backlash; (3) There are mechanical constraints on the positional relationship of the fingers. There were problems with receiving the test.

The present invention solves the above-mentioned drawbacks, and provides a hand that can grip workpieces of different sizes without changing the gripping center point, and that can perform stable operations over a long period of time. The purpose is to use the pressure of a fluid sealed in a closed space as a means of power transmission between at least one of multiple fingers simultaneously driven by the same drive source and the drive source. It is characterized by being configured as follows.

Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, 1 is a robot body connected to a control device 11, 2 is an arm attached to the robot body 1, and 3 is a hand body attached to the arm 2 and having three fingers 4 to 6. . The guides 41, 51, 61 are arranged at equal intervals on a circumference centered on the curvature fingers 4 to 6 (referred to as center points) and are engaged to move linearly along guides 41.51.61 fixed to the hand body 3. There is. The guides 41, 51, 61 are arranged in the same plane radially with respect to the center point 7 and angularly shifted by 120@ from each other.

In other words, fingers 4 to 6 always form a straight line 40.50 passing through center point 7.
．． 60, and one claw 42, 52, 62 is formed at the tip thereof. These claws 42° 52.62 are respectively the actual straight line 4
It has flat parts in a direction perpendicular to 0, 50, and 60, and these flat parts are provided with anti-slip grooves for holding a workpiece (not shown). Further, one ends of bellows 44, 54, 64 are respectively attached to the base of the front cover, and the other ends of these bellows 44, 54, 64 are fixed to the hand main body 3, respectively. Furthermore, the bellows 44, 54.64 are connected to the other bellows 46, 56.66 via conduits 45, 55.65, respectively.The latter bellows 46.56.66 has one end connected to the hand body 3. , the other end is fixed to the plate 84, respectively.

The plate 84 is a motor 8 fixed to the hand body 3.
It is integrally coupled with a nut 82 that is screwed into a screw 81 provided on an output shaft 80 of the output shaft 80, and is fixed to the node body 3,
and a guide bar 83 provided parallel to the output shaft 80.
is slidably engaged.

llJ bellows 44, 54.64 have the same cedar shape, bellows 46. The bellows 44, 46 and the conduit 45 form a closed space A in which an incompressible fluid 9 such as pressure oil is sealed.

Similarly, the bellows 54, 56 and the pipe 55 form a sealed space B in which the incompressible fluid 9 is enclosed, and the bellows 64, 66 and the pipe 63 form a sealed space C in which the incompressible fluid 9 is enclosed.

Next, the operation of this embodiment configured as described above will be explained.

First, the bellows 44, 54.64 on the finger side are in a contracted state, and the bellows 46, 56.66 on the motor side are in an extended state.
Assume that the workpiece gripping surfaces of the claws 42, 52, and 62 are located farthest from the center point 7 and equidistant from the center point 7 due to the retreat of the fingers 4 to 6, and the nut 82 is located at the right end of the screw 81.

In such a state, when the control device 11 outputs a command to grasp the workpiece to the hand, the electric motor 8 rotates and the output shaft 80 is rotated by the action of the ball screw formed by the screw 81 and the nut 82. The nut 82 moves to the left. For this purpose, the plate 84 connected to the nut 82
Similarly, in the leftward direction, the bellows 46, 56, and 66 contract uniformly. Due to this contraction, the pressure oil 9 discharged from the bellows 46°56.66 is transferred to the pipe 45°55.
65 and into the bellows 44, 54.64, respectively, so that the bellows 44, 54.64 are equally expanded.

Therefore, the fingers 4 to 6 move forward in equal amounts to each other along the guides 41, 51, 61, so that the workpiece gripping surfaces of the claws 42, 52, 62 are mutually related to each other so that they are equidistant from the middle 6 point 7. The robot moves forward while maintaining the cylindrical workpiece 10 as shown in FIG. In order to hold the workpiece 10 in this way, the above operation can be performed until the load acting on the electric motor 8 reaches a constant value.
By changing this value, the holding force can be controlled. In this case, it is clear from the explanation in part 1 that the main axis of the workpiece 10 passes through the center point 7 regardless of the outer diameter of the workpiece.

In this embodiment, the bellows 44, 54, and 64 are each elastically deformed and act as springs to match the pressure hydraulic force, so that
The fingers can perform concentric movements regardless of the posture of the hand both when gripping and releasing the workpiece IO.

FIG. 4 shows an embodiment in which a cylinder and a spring are used in place of the bellows in the embodiment shown in FIG. 2, and hydraulic pressure is used as the driving source. That is, fingers 4 to 6 are cylinders 440
, 540, 640, and springs 441, 541, 641 are attached to them, respectively.These springs 441, 541, 64
1 is fixed at both ends to a cylinder 440 and a claw 42, a cylinder 540 and a claw 52, and a cylinder 640 and a claw 62, respectively, and acts in the direction of moving the fingers 4 to 6 closer to the center point 7, respectively. The finger temperature cylinders 440, 540, 640 are each connected to a drive cylinder 460, 560, 660 via a conduit 450, 550, 650, and the pistons of these cylinders 460, 560, 660 are connected to a piston 820 of integral construction. It is formed. This piston 820
are the piston 810 and rod 81 of the driving cylinder 800.
1, and driving pressure oil is supplied and discharged to the cylinder 800 through conduits 801 and 802.

Now, when pressure oil is supplied from the pipe line 802 to the drive cylinder 800, the piston 810 moves to the right, so the piston 820 also moves to the right via the rod 811, so that Pressure oil 9 is pipe 450
, 550, 650 to drive side cylinders 460, 560.
, 660, respectively. In this case, the finger temperature cylinders 440, 540, 640 and the driving cylinder 4
If the comrades 60, 560, and 669 are formed in the same shape, and the springs 441, 541, and 641 are formed in the same manner, the fingers 4 to 6 can be moved uniformly toward the center point 7 to grip the workpiece 10. can do. Conversely, in order to release the grip on the workpiece 10, pressure oil may be supplied to the right chamber of the driving cylinder 800 through the conduit 801, and the operation opposite to the above may be performed.

In this embodiment, one end of the pipe lines 450, 550, and 650 is connected to the work side of the finger temperature cylinders 440, 540, and 640, respectively, but they may be connected to the opposite side of the workpiece. According to this embodiment, even if the pressure of drive pressure oil decreases due to a power outage while handling a workpiece, the spring 4
Since the workpiece 10 is gripped with a force of 41,451°461, there is no danger of it falling.

Another embodiment shown in FIG. 5 eliminates the spring in the embodiment shown in FIG.
640 and the drive side cylinder 830 through a pair of oil supply and drain pipes 45.
0, 470, 550, 570, and an electric motor 8 in place of the driving cylinder.
, a reduction gear 812 and gear mechanisms 803 and 804 are used.

To explain the structure in further detail, the output shaft 80 of the electric motor 8 is connected to a binion 804 that meshes with a rank 803 via a reducer 812, and the rack 803 is connected to a cylinder 830.
is fixed to a rod 811 directly connected to a piston 820. The piston 820 includes a sub cylinder 460,
The 560°660 piston part is integrally machined, and its sub cylinders 460, 560, 660 are made of 450°5 pipes.
50, 650 and 470, 570, 670 to both ends of the cylinders 440, 540, 640, respectively.

The above cylinders 460, 560, 660 comrades and 440
, 540, and 640 are formed in the same shape, and the former cylinder has a head pressure receiving area of 8hH, the latter cylinder has a head side pressure receiving area of 5o11, and a rod side pressure receiving area of 801. Rod 81 of % drive cylinder 830
Assuming that the first side pressure receiving area is SAL, each cylinder is designed so that the relationship shown in the following equation (1) is established between the pressure receiving areas.

To explain the operation of this embodiment (FIG. 5) having such a table configuration, first, when the electric motor 8 is driven, the reduction gear 8
Since the pinion 804 rotates through the rack 80
3 moves. If the direction of movement of the rank 803 is to the left in the figure, the piston 820 moves to the left via the rod 811. By moving the piston 820 to the left, the pressure oil 9 in the sub cylinders 460, 560, 660 is transferred to the pipe 4.
50.550,650 then finger temperature cylinder 440.54
0.640, piston 442.542,64
2 to push out each of the fingers 4 to 6 toward the center point 7. In this case, each finger temperature cylinder 440, 540, 64
The pressure oil sealed on the Rondo side in 0 is connected to pipes 470 and 570.
, 670, and is discharged to the driving side sub-cylinder 460, 560°660. Since the relationship of equation (1) above is established between the pressure receiving areas of the respective cylinders, the balance of the pressure receiving pressure of each cylinder due to the pressure oil 9 is maintained. Even if the fingers 4 to 6 are removed, it is possible to position the fingers 4 to 6 at arbitrary positions.

Another embodiment shown in FIG.
The difference is that the bellows 54, 56 and the conduit 55 for operating the motor are eliminated, and the finger 5 is directly connected to a plate 84 that is linked to the electric motor 8, and the other structures are the same, so a description thereof will be omitted. In this case, the bellows 44, 46, 64, 66 are all formed in the same shape. According to this embodiment, it is possible to use a small number of mechanical parts to provide the desired function.

Other embodiments shown in FIGS. 7 and 8 are functionally similar to the embodiment shown in FIG. The difference is that the plane is spatially arranged on the upper side where it does not contact the driving portion and the driving side bellows 46.degree. This embodiment is suitable for gripping a flat disk-shaped workpiece at its end.

In each of the above embodiments, if precision is required to the extent that the compressibility of the pressure oil 9 becomes a problem, the pipes 45, 55, 65
or 450,550,650 and 470,570
, 670 are formed to have the same length, it is possible to operate the fingers while maintaining concentricity with high precision. In addition, in each implementation row, we have explained the case where there are three indexes and they are attached at angles shifted by 120 degrees, but this is not limited to this, and the application also applies when the fingers are not on the same plane. It is possible.

As explained above, according to the present invention, in addition to using hydraulic pressure, fingers can be placed in any positional relationship without mechanical constraints, and moreover, it is possible to use a small number of mechanical parts. However, accuracy and reliability can be improved. Furthermore, it is possible to grip workpieces of different sizes without changing the gripping center point.

Furthermore, in the present invention, the workpiece gripping fingers are driven by hydraulic pressure, and all the reaction force from the workpiece is received in the direction of the main axis of the fingers, so that no unreasonable force is applied to the mechanism of the fingers themselves, resulting in stable operation over a long period of time. can be made to do so.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an outline of a general industrial robot equipped with the node of the present invention, and FIGS. 2 and 3 are configurations showing one embodiment of the robot node of the present invention. 7 and 8 are plan views and side views showing still other embodiments of the present invention. 4 to 6...Fingers, 42, 52. 62...nail, 44,5
4゜64...Bellows, 45,55.65...Pipeline, 46゜56.66...Bellows.

Claims (1)

[Claims] 1. In a robot hand in which a plurality of fingers are simultaneously driven by the same drive source, as a power transmission means between at least one of the fingers and a driving IJJ taku. A robot hand characterized in that it is configured to use the pressure of a fluid sealed in a closed space. 2. The robot hand according to claim 1, wherein the closed space of the assistance transmitting means is constituted by a bellows or a cylinder and a conduit. 3. The robot hand according to claim 1, wherein the closed space of the power transmission means is constituted by at least one of a cylinder, a bellows, and a conduit.