JPS5810488A - 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 gripping a workpiece used in an industrial robot or the like, and particularly to a hand for gripping a workpiece having a circular cross section.

Robotic hands, which are primarily used to load and unload workpieces onto machine tools, are generally used to grip workpieces with circular cross sections. Therefore, there is a need for a robot hand that can cut pieces into pieces without changing the position of the central axis of the workpiece even if the shape and dimensions of the workpiece change.

In order to satisfy this demand, a plurality of fingers provided on the robot hand may be moved concentrically. In this case, in order to reduce production costs, a method is generally adopted in which a single drive source is used, and power is transmitted to each phase through a mechanism such as a gear train to perform the gripping operation. There is.

In the conventional hand as described above, since the drive source and the power transmission mechanism are housed in the frame of the hand, the mechanism of the power transmission system becomes complicated, and the hand itself inevitably becomes larger. If an attempt was made to make the hand smaller, the power transmission system would be strained, so the payload would have to be reduced, and there was a risk that reliability would drop.

Furthermore, since the drive source or power transmission system must be placed on the exterior of the frame of the hand, there are problems such as interference between the hand and the workpiece or peripheral equipment.

Furthermore, since power is sequentially transmitted to the power transmission system for driving each phase, fingers placed far from the drive source may be affected by backlash caused by the gear train of the power transmission system. , this may lead to a decrease in sheath strength or an increase in katas.

In view of the above, an object of the present invention is to provide a robot hand which has a simple structure, is small in size, and has high reliability. A spiral groove is provided in the frame of
At least three guide holes are provided radially in the other frame, and fingers are fitted into these kite holes so as to be movable in the radial direction, and the protrusions provided on the fingers are engaged with the spiral grooves. It is characterized by:

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

No. 11 shows a sedentary robot to which the present invention is applied, in which 1 is a robot, 2 is an arm of 1, 3 is a robot hand of this embodiment attached to arm 2, and 9
is a control device connected to the robot 1.

The hand 3 has a structure as shown in FIGS. 2 and 3. That is, 4 is at least three kite holes 6A~
6C is a fixed frame provided radially at intervals of 120°, 5 is a movable frame that is layered on the fixed frame 4 so as to rotate around the center point 8 of the fixed frame 4, and this movable frame 5 A spiral $7 is provided on the surface where the fixing frame 4 is joined. 10 is an electric motor attached to the center of the fixed frame 4, and its output @
ioa is connected to the movable frame 5.

11A to IIC are respectively fitted into guide holes 6A to 6C provided in the fixed frame 4, and
It is a finger provided so as to move along A to 6C, and its protruding portions 11AJI to 110a are provided in a spiral #l! on the movable frame 5. It is inserted in 7.

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

When the electric jl&10 is driven, the movable IIh frame 5 rotates relative to the fixed frame 4, so the spiral groove 7 provided in the movable frame 5 also rotates about 80 turns around the rotation center. For this reason, the position of @wound #lI7 provided in the fixed frame 4 at the positions of the nine-kite holes 6A to 6C moves in the radial direction, so that the finger protrusion 11A that fits into the groove 7! 1 to 110a are moved in the radial direction corresponding to the movement of spiral #I#7. That is, the fingers 11A to IIC move along the guide holes 6A to 6C, respectively, and also move in the radial direction toward or away from the rotation center 8.

The shape of the spiral #$7 and the projections 1 of fingers 11A to IIC
If the shapes of fingers 18 to IIC are processed to satisfy a certain relationship, the fingers 11A to II can be used to drive the electric motor 1o.
C can be operated concentrically with respect to the center of rotation 8. Therefore, even when the workpieces have different outer diameters, it is possible to grip the workpieces so that the center axis of the workpieces always coincides with the rotation center 8.

As a specific example, the shape of spiral #117 is processed so that it becomes the following equation (1) in polar coordinate system representation with rotation center 8 as the origin, r = k # -10
, (1) where r: m diameter length (W), θ: 1IdJ diameter angle (radian), k: constant finger protrusion 11Aa ~ 11Ca (7) position fkllA
If the distances from the workpiece gripping surface of ~11C are processed as shown in the following equations (2) to (4), the above-mentioned concentric operation can be easily realized.

t, =L...
・(2) However, L: constant, π: pi If the above k is set to = -, then every time the movable frame 5π rotates with respect to the fixed frame 4, the finger 11A
~11C will move in the radial direction by 2 m.

In this embodiment, the movable frame 5 is provided with a circular groove 7, and the finger 1
The protrusion ItS11 that fits into the #117 above in 1A to IIC
A spiral protrusion is provided on the movable frame 5, and fingers 11A to 11 are provided respectively.
c may be provided with a groove in which the spiral protrusion fits.

4 and 5 show another embodiment, in which a fixed frame 4 is provided with a spiral groove 7, a movable frame 5 is provided with a plurality of guide holes 6A to 6c, and these guide holes 6A are provided with a plurality of guide holes 6A to 6c. It has a structure in which fingers 11A to 11C are respectively fitted into fingers 11A to 6c so as to move in the radial direction.

Electric again! ! Fix I6 close to arm 2 7 frame 4
A circular guide portion 4a centered on the rotation center 8 is projected onto this fixed frame 4, and this guide portion 4a
By supporting the movable frame 5 and providing rkJK teeth 5a on the outer circumference of the movable frame 5, and meshing the teeth 5a with the gear 12 attached to the motor shaft 6m,
The movable frame 5 is configured to be rotated via an electric motor 6. The embodiment constructed in this way operates in the same manner as the embodiment shown in FIGS. 2 and 3, and exhibits the same effects.

In the above embodiment, a case is explained in which a plurality of fingers are driven while maintaining a concentric positional relationship. It is also applicable to the case where the device is configured and driven so as to be arranged.

As described above, according to the present invention, it is possible to achieve miniaturization with a simple structure, and to stably grip a workpiece and improve reliability by moving a plurality of fingers concentrically.

Further, according to the present invention, since all the mechanisms of the power transmission system from the drive source to each phase are configured in the same manner, it is possible to make the operating characteristics of each phase completely four-dimensional. Consequently, it is possible to perform a good gripping operation by minimizing variations in gripping accuracy and backlash caused by backlash in the power transmission system.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an industrial robot to which the present invention is applied, FIGS. 2 and 3 are front and side views showing an embodiment of the robot hand of the present invention, and FIGS.
The figures are a front view and a side view showing another embodiment of the present invention. 4...Fixed frame, 5...-Movable frame, 6A~
6C... Guide hole, 7... Spiral groove, IIA-II
C...Finger, 11A1-11CJI...Protrusion. Figure 1 Punishment 2nd AA ¥13 Figure! f35 diagram

Claims (1)

[Claims] It has a fixed frame and a movable frame that are concentrically combined, one frame is provided with a spiral hook, the other frame is provided with at least three guide holes radially, and the fingers are inserted into these guide holes. 1. A robot hand, characterized in that the hand is inserted into the hand so as to be movable in a radial direction, and a protrusion provided on the finger engages with the spiral groove.