JPH0224087A - Industrial robot - Google Patents

Abstract

PURPOSE:To permit the operation at high speed and with high precision by reducing the inertia performance of the part which is revolved on a horizontal plane such as the second direct drive motor and a robot arm. CONSTITUTION:The revolution shaft line of the rotor 7 of the first direct drive motor 6, i.e., a vertical axis line 1 and the revolution shaft line of the motor 16 of the second direct drive motor 15, i.e., a vertical axis line 1' are at the perfectly or nearly adjusted positions. Therefore, the second direct drive motor 5 having a relatively large weight is at the position in the perfectly or nearly adjusted position to the first direct drive motor 6, and the members having each relatively small weight such as robot arm 2 are arranged at the positions remarkably separated to the side from the revolution shaft line of the rotor 7. Therefore, the inertia performance of the part which is revolved around the vertical axis line 1, together with the rotor 7 when the first direct drive motor 6 is driven, in other words, each inertia performance of the second direct drive motor 5 and the robot arm 2 is reduced.

Description

[Detailed Description of the Invention] The present invention relates to an industrial robot used for conveying or assembling various articles, and in particular to an industrial robot using a direct drive motor. be.

2. Description of the Related Art A conventional industrial robot having the configuration shown in FIG. 4 is known. In other words, this industrial robot
A direct drive motor 106 whose stator is fixed to a stationary base 109 and whose rotor rotates around a vertical axis 101, and a robot arm 102 which is fixed to the direct drive motor 106 and extends horizontally. , and a motor 105 fixed to one end of the robot arm 102. Inside the robot arm 102 are a threaded rod 103 that extends horizontally and has one end connected to the output shaft of the motor 1o5, and a threaded shaft 103.
A slide 104 is provided having a nut 104a that is threaded into the slide. A tool (not shown) or a chuck for gripping and releasing an article can be attached to the slide 104.

The above industrial robot has a direct drive motor 10
6 to drive the robot arm 1 integrally with the motor 1.05.
02 causes a rotational movement in the horizontal plane of the slide 104, and by driving the motor 105 to rotate the threaded rod 103, the slide 10
4 in the horizontal plane.

Problems to be Solved by the Invention In the above prior art, the motor 105, which is a relatively heavy member, is located at a position separated laterally by a considerable distance from the rotor axis of rotation of the direct drive motor 106, that is, the vertical axis 101. Arranged. Therefore, the inertia of the parts that rotate around the vertical axis 101 (i.e., the robot arm 102, the motor 105, etc.) increases,
The problem is that it is not suitable for high-speed operation. In other words, inertia is an amount proportional to the moment of inertia, which is generally expressed as GD2, but when this inertia increases, the robot arm 102, motor 105, etc.
This makes it difficult to repeat operations such as rotating the object by a predetermined angle around the object and stopping it at high speed and with high accuracy.

An object of the present invention is to provide an industrial robot that solves the problems of the prior art.

In order to solve the above-mentioned problems of the prior art, the industrial robot of the present invention has a stator fixed to a stationary part and a rotor rotating about a vertical axis. 1
a direct drive motor; a support fixed to the rotor and having a motor support part and an arm support part above the first direct drive motor; a robot arm slidably attached to the arm support; a stator fixed to the motor support; and a rotor arranged to rotate about a vertical axis fully or substantially aligned with the vertical axis. a second direct drive motor, and an arm sliding mechanism for producing the linear movement of the robot arm, and the arm sliding mechanism includes a rack fixed to one side of the robot arm and a second direct drive motor. The drive motor has a gear fixed to the outer periphery of the rotor of the drive motor and engaged with the rack.

Embodiment FIGS. 1 to 3 show an industrial robot according to an embodiment of the present invention. This industrial robot consists of a base 9 constituting a stationary part of the industrial robot, and a first base 9 provided on the base 9.
The first direct drive motor 6 has an annular stator 8 and a rotor 7 arranged around a vertical axis 1, the stator 8 being connected to the base by bolts 10 at the bottom. It is fixed to the stand 9 and has an annular excitation coil 8a. The rotor 7 has an annular excitation coil 7a whose inner circumference faces the outer circumference of the excitation coil 8a.
When a is energized, it rotates around a vertical axis 1.

A support body 12 is fixed to the upper end of the rotor 7 with bolts 30, and this support body 12 is a motor support part that supports the second direct drive motor 5 at a position above the first direct drive motor 6. 12a, and an arm support portion 12b that supports the robot arm 2.

The second direct drive motor 5 is connected to the vertical axis 1
The stator 17 has an annular stator 17 and a rotor 16 arranged around a vertical axis 1' completely or substantially aligned with the motor support 12a of the support 12, the stator 17 being fixed at the bottom by bolts 15 to the motor support 12a of the support 12. , has an annular excitation coil 17a. The rotor 16 has an excitation coil 16a whose outer circumference faces the inner circumference of the excitation coil 17a.

17a is adapted to rotate about a vertical axis 1' when energized.

The arm support portion 12b of the support body 12 is located on the side of the second direct drive motor 5 and supports the robot arm 2. The robot arm 2 includes a main body part 2a extending linearly in a horizontal plane, a bent part 2b bent in a 5-shape from the tip of the main body part 2a in the same horizontal plane, and a bent part 2b provided at the tip of the bent part 2b. The main body part 2a is linearly slid in the longitudinal direction of the main body part 2a within a horizontal plane by the arm support part 12b. Supported to make it possible.

A gear 18 is fitted onto the outer periphery of the upper end of the rotor 16 of the second direct drive motor 5, and is fixed with bolts 19. Further, a rack 21 is fixed to the side surface of the main body 2a of the robot arm 2 with bolts 20, and this rack 21 is engaged with the gear 18. These gears 18 and racks 21 are arranged so that when the second direct drive motor 5 is driven and the rotor 16 rotates around the vertical axis 1', the robot arm 2 is moved along the arm support 12b in a straight line. It constitutes an arm sliding mechanism to generate the

In addition, 22 and 23 in the figure are bearings, 24.25.2
6°27 indicates piping for electrical wiring. Above piping 2
4°25 extends through a through hole extending axially through the central portions of the first and second direct drive motors 6.5.

The industrial robot of the illustrated embodiment has the above-described configuration, and when the first direct drive motor 6 is driven to rotate the rotor 7 about the vertical axis 1, the support 12 is rotated.
rotates together with the rotor 7, and thus the second direct drive motor 5 and the robot arm 2 rotate together with the support 12 about the vertical axis 1. In this way,
A rotational movement of the robot arm 2 in the horizontal plane occurs. Also, when the second direct drive motor 5 is driven to rotate the rotor 16 around the vertical axis 1', the gear 1
8 and the rack 21, the robot arm 2 slides along the arm support 12b, thus causing a linear movement of the robot arm in the horizontal plane. Therefore, with the article holding portion 2C of the robot arm 2 holding, for example, a chuck for gripping and releasing an article, the operations of the first and second direct drive motors 6.5 are appropriately controlled. By causing the chuck to grip and release the article in synchronization with the movement of the robot arm 2 according to the control, operations such as transporting and assembling the article can be performed.

However, in this industrial robot, the axis of rotation of the rotor 7 of the first direct drive motor 6, that is, the vertical axis 1, and the axis of rotation of the rotor 16 of the second direct drive motor 5, that is, the vertical axis 1'. in a completely or nearly aligned position. In other words, the second
The direct drive motor 5 of the first direct drive motor 6 is located in a position completely or substantially aligned with the first direct drive motor 6, and a relatively light weight motor such as the robot arm 2 is located at a position considerably laterally separated from the rotor axis of rotation. The members are arranged. Therefore, when the first direct drive motor 6 is driven, the inertia of the parts that rotate together with the rotor 7 around the vertical axis 1, such as the second direct drive motor 5 and the robot arm 2, is reduced. , it becomes possible to perform high-speed operation with high precision.

The industrial robot of the illustrated embodiment rotates the robot arm 2 in a horizontal plane by driving the first direct drive motor 6, and rotates the robot arm 2 through the gear 18 and rack 21 by driving the second direct drive motor 5. This causes the robot arm to move linearly in a horizontal plane. Therefore, its configuration is a low rigidity mechanism or a high compliance mechanism. That is, for example, when the robot arm 2 is rotating in a horizontal plane and a resistance force is applied to the robot arm to prevent its rotation, the robot arm will not try to forcefully rotate beyond a predetermined amount, and will overcome the resistance. The force is absorbed by the first direct drive motor 6. Similarly, when the robot arm 2 is moving linearly in a horizontal plane and a resistive force is applied to the robot arm to prevent the robot arm from moving, the second direct drive motor 5 absorbs the resistive force. Therefore, in this industrial robot, there is a possibility that the above-mentioned resistance force will be applied to the robot arm 2 from the article held in the article holding part 2C of the robot arm 2, and therefore the movement of the robot arm will not be flexible or It can be suitably used for assembly work that requires flexibility.

Effects of the Invention As is clear from the above, the industrial robot of the present invention has a structure in which the inertia of the parts that rotate in a horizontal plane, such as the second direct drive motor and the robot arm, is small, so that it can be operated at high speed and This has the effect of allowing highly accurate operation.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an industrial robot according to an embodiment of the present invention, Fig. 2 is a top view of Fig. 1, Fig. 3 is a left side view of Fig. 1, and Fig. 4 is a conventional industrial robot. FIG. 1. Ding... Vertical axis line, 2... Robot arm, 5.
... Second direct drive motor, 6... First direct drive motor, 7... Rotor, 8...
Stator, 12... Support body, 12a... Motor support part, 12b... Arm support part, 16... Rotor, 1
7... Stator, 18... Gear, 21... Rack.

Claims (1)

[Claims] (1) a first direct drive motor having a stator fixed to a stationary part and a rotor adapted to rotate about a vertical axis; a support body having a motor support part and an arm support part; a robot arm slidably attached to the arm support part so as to be capable of linear movement in a horizontal plane; and a stator attached to the motor support part. a second direct drive motor fixed and arranged to rotate about a vertical axis with a rotor fully or substantially aligned with the vertical axis; and an arm sliding mechanism for producing the linear movement of the robot arm. and the arm sliding mechanism includes a rack fixed to one side of the robot arm, and a gear fixed to the outer periphery of the rotor of the second direct drive motor and engaged with the rack. An industrial robot featuring: