JPH01177990A - Direct drive robot - Google Patents

Abstract

PURPOSE:To more lessen fear of cable cutting by providing a limit switch for limiting a working range of a front arm in the space wherein the drive motors of a base arm and the front arm are opposing each other. CONSTITUTION:When the relative angle of a base arm 4 or front arm 15 exceeds the angle within the predetermined working range for any reason, the proximity switch 16a (or 16b) of the connecting plate 7 fixed to the rotor 5a of a direct drive motor for driving the front arm detects the target 17 of the target mounting plate 18 attached to the rotor 2a of a direct drive motor 2 for driving the base arm to cut-off the motive power to the direct motors 2 and 5. This cutting-off serves to protect the members constituting a robot and keep human beings safe. The proximity switches 16a and 16b are provided not to the base arm 4 or front arm 15 but to a position nearer a fixing section resulting in lessened fear of cable cutting.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a direct drive robot using a direct drive motor with a hollow shaft structure.

(Prior art) Conventionally, in an articulated robot using a direct drive motor, the motor for moving the base arm and the motor for moving the tip arm are installed on a fixed member, and the motor for moving the tip arm is installed in the hollow part of the motor for moving the base arm 191j. A power transmission shaft connected to the output shaft is inserted through the power transmission shaft, and a power transmission shaft such as a belt or a link is connected between this power transmission shaft and the tip arm rotating shaft which is pivotally supported at the tip of the base arm which is connected to the output shaft of the base arm drive motor. Japanese Patent Application Laid-open No. 62-25 as an industrial robot that transmits rotating house power using a transmission means.
There is one shown in No. 1090.

According to this industrial robot, the size of the arm, which is the movable part of the robot, can be made small, which has the effect of making it possible to obtain a robot with good dynamic characteristics.

(Problem to be solved by the invention) The wiring and piping required for the robot are: ■ Connection with the end effector, ■ Connection with the actuator, ■ Connection with a rotation detector such as an encoder, and ■ Overrun detection sensor for each arm. A possible connection is possible.

In JP-A No. 62-251090, the above-mentioned ■.

Regarding (2) and (2), the positions of the connection targets are disclosed, so it is possible to connect these and fixed parts with wiring and piping, but regarding (2), the installation location is not disclosed.

Therefore, it is unclear how the wiring should be done, but since most normal overrun detection sensors are installed on arms that move relatively,
Among the overrun detection sensors for industrial robots proposed in No. 2-251090, the overrun detection sensor for detecting the relative angle between link 8 and link 9 is link 8°9.1.
It is presumed that it is provided in one of the 0.11 movable parts. This is because in this case, if the absolute angles of the drive motors of link 8 and link 9 were detected individually, it would not be possible to detect an overrun in the relative angle, so a detection sensor was provided on the link, which is a movable part, so that the relative angle could be detected. Because it has to be done.

By the way, robots driven by direct drive motors have faster arm rotation speeds than conventional robots using reduction gears, and there is a risk of wire breakage if sufficient consideration is not given to the wiring connected to movable parts such as arms.

For this reason, it is common practice to use the hollow part of a direct drive motor for wiring, but when the shaft is passed through the hollow part of the motor as in JP-A-62-251090, wiring Therefore, there was a problem in that there was no available hollow space at all, or there was only a very small amount of available hollow space, making it impossible to use all of the wiring cables.

(Means for Solving the Problems) The present invention aims to solve the above-mentioned problems by attaching a direct drive motor for driving the base arm to the base, and connecting the base arm to the output shaft of the motor for driving the base arm. At the same time, a motor for moving the tip arm is provided on the opposite side of the motor for correcting the base arm so as to be substantially coaxial with the base arm, and one end of the power transmission shaft passes through the hollow part of the motor for moving the base arm. is connected to the output shaft of the tip arm drive motor, and the other end is rotatably connected to the tip arm rotation shaft pivotally supported at the tip of the base arm using a rotation transmission means, in which the base arm polishing motor and the tip arm This device is characterized by a limit switch that limits the working range of the tip arm in the space facing the drive motor.

A detailed explanation will be given below based on an embodiment shown in one figure. In FIG. 1, a direct drive motor 2 for driving a base arm is fixed to a base 1. A base portion 4a of a base arm 4 is connected and fixed to a rotor 2a of the direct drive motor 2 via a base arm rotation shaft 3. On the other hand, a direct drive motor 5 for driving the tip arm is fixed to a fixed base 6 to which the base 1 is fixed so as to be coaxial with the base arm 4 of the direct drive motor 2 on the opposite side. The rotor 58 of the direct drive motor 5 for moving the tip arm is connected to one end 8a of the power transmission shaft 8 via the connecting plate 7. The power transmission shaft 8 passes through the hollow portions of the direct drive motor 2 and the base arm rotating shaft 3, and its other end 8b projects into the base arm 4. At the tip 4b of the base arm 4, a tip arm rotating shaft 9 is supported by a bearing 10, which is parallel to the direct drive motor 2. A pulley 11 is coaxially fixed to the tip arm rotating shaft 9, and is rotationally connected to a pulley 12 fixed to one end 8b of the power transmission shaft 8 by a belt 13. Furthermore, a base 15b of a distal arm 15 having an end effector 14 provided at its distal end 15a is fixed to the distal arm rotating shaft 9.

On the other hand, the connecting plate 7 has a base arm 4 and a distal arm 15.
Proximity switch 16 for detecting overrun relative to
a and 16b are provided.

Further, a target mounting plate is fixed to the rotor 2a of the direct drive motor 2, on which a target 17 for operating the proximity switches 16a and 16b is attached. 19 is a cable connected to the end effector etc. provided on the distal arm, and is connected from the end effector to the distal arm 15, the rotating shaft 9, the pulley 11, and the pulley 12.
゜It is led to the fixed part through the hollow part of the power transmission shaft 8 and the hollow part of the direct drive motor 5.

20 is a cable for the proximity switches 16a and 16b.

21 is a bearing that pivotally supports the upper part of the power transmission shaft 8; 22
is a mechanical stopper for the tip arm 15 provided on the base arm 4.

2b, 2c, 5b, and 5c are the stators and bearings of the direct drive motor 2 and the direct drive motor 5, respectively.

Next, the effect will be explained. When the relative angle of the base arm 4 or the tip arm 15 attempts to exceed the determined working range for some reason, the target 17 provided on the target mounting plate 18 attached to the rotor 28 of the direct drive motor 2 is directly driven. The proximity switch 16a (or 16b) provided on the connecting plate fixed to the rotor 5a of the motor 5 detects this and cuts off the power to the direct drive motors 2 and 5, thereby protecting the components of the robot and protecting the human body. Measure safety against. In this case, the proximity switch 16a
,, 16b is not provided on the base arm 4 or the distal arm 15, but is provided closer to the fixed part, so there is less risk of wire breakage.

(Effect) According to the present invention, a direct drive motor for moving the base arm is attached to the base, the base arm is coupled to the output shaft of the motor for moving the base arm late, and the base arm is connected to the side opposite to the base arm of the motor for moving the base arm forward. A motor for moving the tip arm is provided so as to be substantially coaxial with the motor, and one end of a power transmission shaft passing through the hollow part of the motor for driving the base arm is connected to the output shaft of the motor for rotating the tip arm,
In the case where the other end is rotatably connected to the tip arm pivot shaft supported by the tip of the base arm using a rotation transmission means, the working area of the tip arm is located in the space where the base arm drive motor and the tip arm movement motor face each other. Since a limit switch is provided to limit the diameter of the cable, even if the shaft passes through the hollow part of the direct drive motor, the cable passed through the shaft can be made small in diameter. It becomes easy to store all the cables connected to the robot inside the robot.

In addition, even if the hollow part is small in diameter and only the shaft can penetrate, at least there is no need to connect the cable inside the base arm, and the wiring of the robot only needs to be connected to the tip arm from the outside, which simplifies the wiring. The risk of wire breakage can be further reduced.

Note that if the strength of the target mounting plate 18 and the connecting plate 7 is sufficient, it is also possible to provide the stopper 22 for the tip arm on the target mounting plate 18 and the connecting plate instead of providing it on the base arm 4. In this case, since there is no need for a protruding part caused by a stopper on the movable part of the robot, it has the effect of improving human safety and appearance.In addition, since the stopper is provided at the knocking base, the stopper collides with the power transmission means (here, the belt 13). It also has the great effect of preventing the belt from breaking due to excessive external force.

Further, the arrangement, type, and shape of the center for detecting overrun and the target for operating the center may be any method other than the present embodiment, as long as the relative positions of the direct drive motors 2 and 5 can be detected. Furthermore, in addition to the toothed belt, a metal belt may be used for the belt 13, or a rotation transmission means such as a link other than the belt may be used.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of an embodiment of the present invention. 1...Base 2...Direct drive motor for driving the base arm 3...Base arm rotation shaft 4...Base arm 5...Direct drive motor for tip arm rotation ゛8...Power transmission shaft 9 ...Tip arm rotation axis 15...Tip arm 16a, 16b...Proximity switch

Claims (1)

[Claims] A direct drive motor for driving the base arm is attached to the base, and the base arm is connected to the output shaft of the motor for driving the base arm, and the tip of the motor for driving the base arm is installed so that it is approximately coaxial with the base arm on the opposite side of the motor. A motor for driving the arm is provided, one end of a power transmission shaft passing through the hollow part of the motor for driving the base arm is connected to an output shaft of the motor for driving the tip arm, and the other end is pivotally supported at the tip of the base arm. The tip arm is rotatably connected using the rotation axis and the rotation transmission means, and is characterized by a limit switch that limits the working range of the tip arm in the space where the base arm drive motor and the tip arm drive motor face each other. Direct drive robot.