JPS60201894A - Working unit of industrial 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 work unit attached to the tip of a work arm of a highly versatile industrial robot used in assembly work for high-mix, low-volume production.

Recently, this type of versatile industrial robot has been attracting attention, and as the use of industrial robots increases, it is used for tightening screws to be attached to the tip of the work arm, inserting parts, etc. There is a demand for the development of various work tools. With the development of this type of work tool, there is a demand for a work unit that can arbitrarily change the height of the tip of the work tool in accordance with the height of each work position, even if the height is 5 or 4. In response to this demand, a work unit as shown in FIG. 1 has been developed. This working unit 6 has a housing 7 fixed to an arm (not shown) that is driven by a motor (not shown) and moves on a plane, and a screw shaft 12 and a spline shaft 13 are arranged in this housing 7. has been done. Further, a third motor 8 is disposed in the housing 1 with its drive shaft 9 facing downward, and the third motor 8 is configured to rotate the screw shaft 12 at that position. A change nut 11 that moves together with the spline shaft 13 is screwed into the screw shaft 12, and a third change nut 11 is screwed into the screw shaft 12.
Due to the rotation of the motor 8, the change nut 11 moves up and down along the screw shaft 12, and the spline shaft 13
It is constructed so that it can be raised and lowered in one piece. In order to control the height of the tip of this work unit 6, a method is adopted in which the rotation speed of the motor is detected and feedback control is performed by applying voltage to the motor so that the rotation speed becomes the desired rotation speed. There is. However, if the third motor 8 is rotated to obtain a rotation speed corresponding to a predetermined height, the gravity of the working tool 19 fixed to the spline shaft 13 will cause the working tool 19 to move downward and upward. In this case, there is a difference in the moving speed of the work tool, and in order to compensate for this, the third
An extremely complicated and expensive control device that changes the speed characteristics, acceleration and reaction characteristics, etc. of the motor 8 each time is required, and the work unit! - has some drawbacks, such as not being of practical use.

The present invention aims to eliminate the above-mentioned drawbacks, and embodiments will be described below with reference to the drawings. In FIG. 2 and FIG. 3, 1 is an industrial robot, and a first arm 4 and a second arm are rotated by being driven by a first motor 2 and a second motor 3.
It has an arm 5. A housing 7 of a working unit 6 is fixed to one end of the second arm 5. A third motor 8 is attached to the upper part of the housing 1 with its drive shaft 9 facing downward, and the outer periphery of the drive shaft 9 is filled with grease via an oil seal 10. On the other hand, two change nuts 11 are arranged in the housing 7 so as to be rotatable at that position, and a screw shaft 12 is inserted through the change nuts 11 so as to be screwed into the two change nuts 11. Natsuto 11
The screw shaft 12 is inserted between the screw shafts. Further, a connecting tool 14 integrally connected to a spline shaft 13 (described later) is fixed to the tip of the screw shaft 12, and the screw shaft 1
2 is configured so that it does not rotate. The drive shaft 9 is connected to the change nut 11 via a first gear 15 and a second gear 16.
The screw shaft 12 is configured to move up and down as the screw rotates. Further, the second gear 16 is composed of two gears, and the upper large gear is the first gear 1.
5, and the lower small gear is the third gear 21, which will be described later.
It is configured to mesh with the

A spline shirt 1-13 is disposed in the housing 7 together with the screw shaft 12, and can freely slide up and down without moving its axis via an upper bearing 17 and a lower bearing 18 that are rotatably held. are guided by. Further, this spline shaft 13 is provided with the connecting tool 1.
4 are integrally movably or rotatably connected,
The spline shaft 13 is configured to move together with the screw shaft 12. Further, a working tool 19 corresponding to a predetermined work is fixed to the spline shaft 13, and this working tool 19 is configured to be rotatable by a rotation transmission mechanism 20 fixed to the lower bearing 18.

Further, a reversible sub-motor 22 is fixed to the housing 1, and a third gear 21 is fixed to the tip of the sub-drive shaft 23. This third gear 21
A small gear of the second gear 16 meshes with the small gear of the second gear 16, and the second gear 16 is configured so that the rotation of the sub motor 22 is constantly applied to the second gear 16. Further, a predetermined voltage in a certain direction is applied to the sub motor 22, and the sub motor 22 is configured to obtain rotational torque sufficient to support the gravity of the working tool 19 applied to the screw shaft 12.

In the work unit 6 of the industrial robot, the third motor 8 is rotated according to the height of the work tool 19 at each work position. At this time, a voltage necessary to obtain the rotation speed corresponding to the desired height is applied to the third motor 8, and the third motor 8 rotates. Due to the rotation of the third motor 8, the change nut 11 rotates with respect to the housing 1 by a predetermined number of rotations, and the screw shaft 12, which is threaded therewith, moves down inside the change nut 11. At the same time, the connector 14 is lowered, and the spline shaft 13 is also lowered together. At this time, the change nut 11 is constantly receiving rotational torque in the direction of raising the spline shaft 13 by the submotor 22, and the gravity of the work tool 19 is not applied to the spline shaft 13, so the gravity of the work tool 19 is It hardly affects the control of the third motor 8.

Similarly, when the work tool 19 is raised, there is almost no influence of gravity on the work tool 19, so when the third motor 8 is driven, the predetermined rotation speed is reliably obtained, and the work tool 19 is raised to the predetermined height. Positioned.

As explained above, in the present invention, a sub-motor having a rotational torque adjusted to balance the gravity of a working tool that is being raised and lowered is disposed and is configured to hold a worker at all times. There is no need to change control characteristics such as motor speed characteristics and acceleration characteristics when ascending and descending, and no special control device is required. Not only is it possible to provide a work unit driven by an extremely simple control device, but the motor is also extremely small and only rotates the screw shaft and nut relative to each other. It has the advantage of being able to provide a compact work unit with a large capacity. Moreover, since the influence of gravity on the power tool can be ignored, the lead of the screw shaft can be increased, and as a result, not only can the lifting speed of the power tool be increased, but also the screw shaft and nut can rotate relative to each other after the motor has stopped. Therefore, there is no change in the height of the working tool, there is no hunting of the motor, and there are advantages such as instant positioning.

Although this embodiment describes a work unit attached to the tip of the arm of an industrial Kawaguchi bot, it is a work unit that moves in the Z direction of an orthogonal coordinate type industrial robot consisting of an X direction moving table and a Z direction moving table. Similar effects can be obtained by using the work unit of the present invention as a moving table.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing a conventional example, FIG. 2 is an overall explanatory diagram of an industrial robot according to the present invention, and FIG. 3 is a sectional view of a main part of the present invention. 1 industrial robot, 2 first motor, 3 second motor, 4 first arm, 5 second arm, 6 work unit, 1 housing, 8 third motor, 9 drive shaft, 10 oil seal, 11 change nut, 12 Screw shirt]・
, 13 spline shaft, 14 connector, 15 first
Gear, 16 Second gear, 11 Upper bearing, 18
Lower bearing, 19 Work tool, 20 Dn transfer 31 [11°21
3rd gear, 22 Sub-motor, 23 Sub-drive shaft, Patent applicant: Nitto Sei Co., Ltd. Proprietorship (Method) July 18, 1981 1. Indication of the incident 1982 Patent Application No. 55850 2. Invention Name of Industrial R1 Bot Work Unit 3, Person making the amendment Relationship with the case Patent applicant 20-4 Umegahata, Io-cho, Ayabe-shi, Kyoto Prefecture, [1 clause of the amendment order [1st clause 1982] [June 6, 5] , Specification to be amended 6, Reprint of the specification of the contents of the amendment (no change in content)

Claims (1)

[Claims] (1°) A screw shaft and a change nut screwed thereto are disposed in a housing, and the screw shaft and change nut are relatively moved by a motor,
In an industrial robot that is configured to position a work tool that is arranged to move up and down at a predetermined height by this relative movement, a sub-motor that relatively moves the screw shaft and change nut is separately provided, and this sub-motor has a predetermined movement. A work unit characterized by applying voltage to hold a screw shaft or change nut in an upward direction. (2) A housing having a shaft that can be raised and lowered is attached to one end of an arm that moves on a plane, a screw shaft and a change nut screwed thereto are arranged in this housing, and a motor is arranged in this housing,
In an industrial robot configured to move the shaft parallel to the screw shaft by this motor, a sub-motor is separately provided in the housing to move the screw shaft and change nut relative to each other, and a predetermined voltage is applied to this sub-motor to raise the shaft. A work unit characterized by being held in a direction.