JP2003103488A - Motor hand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor hand capable of preventing seizure of a motor caused by a load applied to a rotary shaft in a damaged or stopped state due to impact of stopping by simple control, and gripping a body to be gripped without dropping it even when supply of a power source is cut off. SOLUTION: In the motor hand, a pair of master jaws 2 is arranged so that it is constantly energized toward a body center by a spring 7, and a cam receiving part 11 is provided on the master jaw. The cam receiving part provided on the master jaw 2 abuts on a tapered cam part 10 formed on a pressing member 9 attached so that it can be reciprocated by a screw shaft 4 and the motor 3 with a torque limiter 13, and the cam receiving part is composed so that the master jaw moves in an opening direction during advance of the pressing member and the master jaw is moved in a closing direction by the spring during retreat of the pressing member.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor hand which is attached to an industrial robot, a transfer device or the like to hold and transfer an object to be grasped.

2. Description of the Related Art As a motor hand, a system in which a rotary motion of a rotary shaft is converted into an opening / closing motion of a master jaw by a motion direction converting mechanism such as a rack and pinion or a cam mechanism is generally used. In the case of a motor hand that uses a motor as a drive source as described above, there is a problem that the gear of the reducer is damaged by the impact when the master jaw stops at the opening / closing end or the work gripping position, and rotation stops at the operating end. There is a problem that the load of the motor is applied to the rotating shaft that is causing seizure, and as a method to solve these problems,
The method of using a motor with a torque limiting function and the method of controlling the rotation of the motor by using a numerically controllable motor are generally used, but the method requires expensive equipment for the motor and control equipment. Therefore, the chuck becomes expensive. In addition, the motor hand has a problem that if the power supply is cut off for some reason while the work is being conveyed, the master jaw moves due to the load applied to the small claws and the work is dropped.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is possible to prevent motor seizure caused by damage due to impact at the time of stopping or load on the rotating shaft in a stopped state by simple control. An object of the present invention is to provide at low cost a motor hand that can be prevented and that can hold a grasped body without dropping it even when power supply is cut off.

As a means for solving the above-mentioned problems, the present invention provides a motor hand according to the present invention, wherein a pair of masters are provided so that a motor hand is constantly urged toward the center of the main body by a spring. A jaw is provided, and a cam receiving portion is provided on the master jaw. The cam receiving portion provided on the master jaw comes into contact with a tapered cam portion formed on a pressing member that is reciprocally attached by a motor with a torque limiter and a screw shaft,
When the pressing member moves forward, the master jaw moves in the opening direction,
The feature is that the pressing member is configured to move in the closing direction by the spring when retracting. A structure in which the master jaw is constantly biased toward the center of the main body by a spring, and the taper angle of the tapered cam part formed on the pressing member that reciprocates with the screw shaft and the nut is an acute angle with respect to the operating shaft of the pressing member. Since it is set, even if the power supply is cut off for some reason, the gripped body is not gripped and dropped. Further, by using a motor with a torque limiter as a motor that is a drive source for reciprocating the pressing member, it is possible to prevent the motor from being damaged by an impact or a load generated during the operation.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a motor hand composed of a drive unit and a motion direction conversion mechanism for converting the operation of the drive unit into the opening / closing motion of the master jaw 2 and the master jaw 2 which is guided by the guide unit to perform the opening / closing operation The part is composed of a motor 3 with a torque limiter, and the motor 3 with a torque limiter is fixed to the body 1 and covered by a motor cover 6. A screw shaft 4 is attached to a rotary shaft protruding from the main body of the motor 3, a nut 5 is engaged with the screw shaft 4, and a motion direction converting mechanism for converting the rotary motion of the rotary shaft and the screw shaft 4 into a linear motion is provided. Is forming. A pair of pressing members 9 each having a tapered cam portion 10 and a stopper 14 attached to an upper end surface thereof are attached to a nut 5 that performs a linear movement at positions symmetrical with respect to the center line of the screw shaft 4. The tapered cam portion 10 formed on the pressing member 9 is disposed so as to be guided by the guide groove 15 formed in the body 1 so as to be able to come into contact with the cam receiving portion 11 of the master jaw 2 performing the opening / closing operation. . A recess is provided in the upper part of the master jaw 2, and a spring pin 8 is press-fitted into the bottom surface of the recess in a protruding state, and a spring 7 is urged into the spring pin 8 so as to constantly urge the master jaw 2 toward the center of the main body. It is installed. Next, the operation of the chuck of the present invention will be described. When electricity is supplied to the motor 3 from the state where the master jaw 2 is stopped at the open end and the rotary shaft and the screw shaft 4 attached to the rotary shaft start to rotate, they are screwed to the nut 5 engaged with the screw shaft 4. The pair of pressing members 9 starts moving upward in the drawing. When the pressing member 9 moves, the master jaw 2 is closed by the spring force while the cam receiving portion 11 provided on the master jaw 2 is kept in line with the tapered cam portion 10 formed on the pressing member 9. When the object to be grasped is grasped by the small claws or the stopper 14 attached to the pressing member 9 contacts the body 1 and the pressing member 9 stops moving, the operation of the master jaw 2 is completed. To do. After completion of the movement in the closing direction, when the motor 3 is rotated in the reverse direction, the nut 5 and the pressing member 9 attached to the nut 5 are moved downward in the drawing by the screw shaft 4. When the pressing member 9 moves downward in the drawing, the tapered cam portion 10 moves the master jaw 2 in the opening direction via the cam receiving portion 11 provided on the master jaw 2 and is attached to the upper end surface of the pressing member 9. The stopper 14 comes into contact with the master jaw 2 to complete the operation.

The motor hand of the present invention employs a motor having a torque limiter as the motor which is the drive unit, so that damage and rotation of parts due to impact when the master jaw is stopped without using an expensive control device. It became possible to prevent the seizure of the motor due to the load generated while the shaft was stopped. Further, the motor hand of the present invention, when gripping the outer diameter of the object to be gripped, has a device structure for gripping the object to be gripped by the spring provided between the pair of master jaws, so that the motor hand is always stable with a constant gripping force. Even if the object to be grasped can be grasped and even if the power supply to the apparatus is cut off for some reason, the object to be grasped can be grasped without dropping. Furthermore, when clamping the object to be grasped by the inner diameter clamp, a drive mechanism consisting of a screw shaft attached to the rotating shaft and a nut can be used to generate a large grasping force with a small motor and In order to convert the rotational movement of the pressing member into the reciprocating motion of the pressing member, a mechanism for changing the moving direction by the screw shaft and the nut is used, and further, the reciprocating motion of the pressing member is converted into the opening / closing motion of the master jaw. Since the angle is an acute angle with respect to the movement direction of the pressing member, the gripping position can be maintained even if the power supply to the motor is cut off, and the gripped object does not drop.

[Brief description of drawings]

FIG. 1 is a front view of this embodiment.

FIG. 2 is a side view of this embodiment.

FIG. 3 is a sectional view taken along line AA of the present embodiment.

FIG. 4 is a front view showing a state in which a master jaw is opened.

[Explanation of symbols]

1 body 2 Master Joe 3 motors 4 screw shaft 5 nuts 6 motor cover 7 springs 8 spring pins 9 pressing member 10 cam section 11 Cam receiving part 12 springs 13 torque limiter 14 stoppers 15 guide groove

Claims (2)

[Claims] 1. A motor for rotationally driving, a screw shaft attached to a rotary shaft of the motor, a nut for engaging the screw shaft to convert rotational motion into linear motion, and a taper shape for linear motion by the nut. In a motor hand composed of a pair of master jaws having a pressing member having a cam portion and a cam receiving portion which is guided by a guide portion and is constantly urged toward the center of the main body by a spring, a torque limiter for a rotating shaft is provided. A motor hand that is characterized by being attached. 2. The taper-shaped cam portion formed on the pressing member and the cam receiving portion pressed by the cam portion provided on the master jaw have an acute angle with respect to the operation axis of the pressing member. The motor hand according to claim 1, characterized in that