JPH0192086A - Joint section for robot - Google Patents

Abstract

PURPOSE: To radiate the generation of heat in a motor so efficiently to the outside by simplifying a structure of each individual articulated part, and further forming a cooling fin in the outside of a motor case side of the articulated part by way of using an element of the motor jointly with a part of the articulated parts of a robot. CONSTITUTION: A tip part of a first arm 2 is of tubular body, using a casing 9 of a direct driving motor 8 jointly, and plural pieces of cooling fins 10 are formed at the outside part, while a central shaft 11 is supported by both up and down bearings 12 free of rotation at a central position on the inside. This central shaft 11 is equipped with a ring magnet 13 on the inside of the casing 9 as a rotor, and its peripheral part is opposed to a stator 14. Since the magnet 13 as the rotor and the stator 14 are installed like that, each individual structure of the articulated parts is simplifiable, and further the fins 10 are installed in a peripheral part at the side of the stator 14, whereby the generation of heat in the motor 8 is efficiently radiable to the outside, thereby eliminating any thermal accumulation in each of the articulated parts.

Description

[Detailed description of the invention] Technical field of invention The present invention relates to joints of robots.

Prior Art For example, the invention disclosed in Japanese Patent Application Laid-Open No. 60-146687 discloses that a direct drive type motor is built into the joints of a robot, and the central axis of the joints is also used as the shaft of the motor. Such a direct drive type motor can achieve the objectives of increasing the movement speed, increasing the precision of positioning, and reducing the weight of the motor part. However, on the other hand, it is unavoidable that the motor generates heat during use, and problems caused by the heat, such as the adverse effects of thermal expansion due to the heat generated by rotating parts such as the encoder, as well as the adverse effects of heat on the internal electrical circuits, are unavoidable.

Therefore, sufficient heat dissipation measures are required for the joints of this type of robot.

OBJECT OF THE INVENTION The object of the present invention is to improve the heat dissipation effect of the joint parts while satisfying the above-mentioned advantages, such as high speed movement, high precision positioning, and light weight of the motor part. .

SUMMARY OF THE INVENTION Therefore, the present invention has a part of the joint part of the robot that also serves as a motor element, a direct drive type motor is built into the joint part, and a heat dissipation motor is installed outside the joint part on the motor case side. forming fins. Further, in the present invention, a cooling fan is provided inside the arm as a measure for heat dissipation inside the joint part, and a measure is taken for the heat dissipation effect by blowing air.

The configuration diagram of the invention shows, as an example, a horizontal multi-joint type robot 1, and the joint portion of the invention is incorporated in the rotational connection portion of the first arm 2 and the second arm 3.

As shown in FIG. 1, the first arm 2 is formed of a hollow body, and its base end portion is attached to a motor shaft 5 of a direct drive motor 4. The motor 4 is housed inside a base 6, and the motor shaft 5 is supported by a bearing 7 on the base 6 side.

The tip of the first arm 2 is a cylindrical body that also serves as the casing 9 of the direct drive motor 8, and has a plurality of cooling fins 10 formed on the outside, and a central axis at the center of the inside. 11 is rotatably supported by upper and lower bearings 12.

Note that this central shaft 11 is hollow to allow wiring, piping, etc. to pass therethrough. This central shaft 11 is provided with an annular magnet 13 as a rotor inside the casing 9, and its outer peripheral portion is connected to a stator 1.
It is facing 4. That is, the stator 14 is connected to the magnet 13 inside the casing 9 together with the field winding 14a.
It is fixed in a state surrounding it while forming a predetermined annular gap.

The upper end of this central shaft 11 is connected to an encoder 15 fixed to the upper surface of the tip of the first arm 2, and the lower end thereof is connected to the upper surface of the second arm 3.
It is connected to its center of gravity. In this way, the first arm 2 on the supporting side moves the second arm 3 on the driven side to the central axis 1.
1, it is rotatably supported. Note that the first arm 2 has a cooling fan 16 directed toward the casing 9 inside.
is arranged, and is provided for cooling the inner surface of the casing 9 by driving it with the motor unit 17.

Furthermore, as shown in FIGS. 2 and 3, the second arm 3 is provided with a vertically moving vertically moving wheel 18 at its distal end. It has two built-in motors 19.20.

That is, one motor 19 is installed inside the second arm 3 in a horizontal state, and the rotation of the motor shaft 21 is transmitted to one side of the endless timing belt 27 via two gears 22 and a transmission shaft 24. The signal is transmitted to the timing boolean 1J25.

In addition, motor shaft 2! is also connected to an electromagnetic brake 23. The timing pulleys 25 and 26 are connected to the second arm 3.
is rotatably supported at its distal end by a vertical support 28 and a horizontal pulley shaft 29,30. The timing belt 27 is wound around these parts, and a part of the timing belt 27 is attached to the housing 31.
is connected to. In this bearing, a housing 31 is attached to the side surface of the support 28 so as to be slidable in the vertical direction, and an internal bearing 32 rotatably supports the upper end portion of the vertical driving wheel 18. This vertical drive wheel 18 has a spline tube 34 at the spline 33 portion.
They are fitted together so that they can move in the axial direction.

The spline cylinder 34 is rotatably supported by a bearing 35 at the tip of the second arm 3, and is integrated with the timing pulley 37 at its outer circumference.

The other motor 20 is mounted facing downward inside the second arm 3, and the rotation of its motor shaft 39 is controlled by a timing belt 42 wrapped around timing pulleys 40 and 41, using a harmonic drive (registered trademark). After being transmitted to the input shaft 44 of the type reducer 43 and decelerated at a predetermined reduction ratio, the timing boot 173 of the output shaft 45 is transmitted.
8. The timing belt 36 finally transmits the signal to the vertical drive wheels 18 via the spline cylinder 34.

As is clear from the figure, the second arm 3 is internally connected to the motor 19, 20, reducer 43, and other transmission shafts 24.
It is constructed in an appropriate shape to accommodate and support such items.

Note that the center of gravity of the second arm 3 can be adjusted by changing the mounting position of, for example, the motor 20 among the motors 19 and 20. Therefore, if a chuck with a different weight or a workpiece held by the chuck is placed at the tip of the vertical drive wheel 18 and the center of gravity of the second arm 3 changes greatly, the central axis 11 becomes the center of gravity of the second arm 3. Considering the unbalanced state of the mounting position of the motor 20, the mounting position can be improved to a balanced state by changing the position of the motor 20.

Operation of the Invention The horizontal articulated robot 1 performs necessary movements by rotating the first arm 2 and rotating the second arm 3 relative to the first arm 2 on a horizontal plane. That is, when the motor 4 rotates, the first arm 2 rotates by a necessary angle about the motor shaft 5 in proportion to the amount of rotation of the motor shaft 5. Similarly, when the motor 8 rotates, the second arm 3 is directly driven by it and changes the angle of intersection with the first arm 2, thereby moving the vertical shaft 18 at the tip to a predetermined position. At this time, motor 4.
Since the rotation of 8 is directly transmitted to the first arm 2 or the second arm 3, the amount of rotation is higher in positioning accuracy than in a system in which rotational force is transmitted through a transmission means in between. will be transmitted below.

On the other hand, if the motor 19 for vertical movement rotates during this period, the rotation is transmitted to the timing belt 27 via the motor shaft 21, gear 22, and transmission shaft 24, so that the vertical driving wheel 18 Moves up and down in proportion to the amount of rotation. Moreover, when the motor 20 for rotational movement rotates,
The rotation is caused by a reduction gear 43 through a timing belt 42-.
Since the speed is further transmitted to the spline cylinder 34 via the timing belt 36, the vertical driving wheels 18 rotate in proportion to the amount of rotation of the motor 20.

When the vertical movement axis 18 moves up and down, even if the acceleration suddenly changes when the motor 19 is started or stopped, or when it accelerates or decelerates, the reaction torque of the motor 19 is at the joint in the direction perpendicular to this, that is, the central axis. 11 and the motor shaft 5, positioning accuracy in the turning direction is not affected by vertical movement and can be maintained at high accuracy. Note that when the motor 19 stops, the electromagnetic brake 23 applies a braking force instead, and in order to fix the rotation transmission system, the vertical driving wheels 18 move in the vertical direction and then stop, and at that position, gravity is applied. It does not move and continues to maintain a predetermined height even under the influence of

Even if heat is generated in the motor 8, that is, in the field winding 14a of the stator 14 during such movement, the heat is transferred to the outer fins 10 of the casing 9, the cooling motor unit 17, and its cooling fan. Under the influence of the airflow caused by 16, efficient cooling is achieved. Therefore, the joint portion does not generate abnormal heat, and does not adversely affect the electric wire inside the central shaft 11, the rotating portion of the encoder 15, or the electronic circuit therein.

Other Embodiments of the Invention In the above embodiment, the joint structure of the present invention is incorporated between the first arm 2 on the support side and the second arm 3 on the driven side. It is also possible to incorporate the stand 6 into the part of the first arm 2 on the driven side as a supporting side.

Further, in the above embodiment, the robot 1 is of a horizontal multi-joint type, but the rotation center of these joint parts may of course be in the horizontal direction, for example, other than the vertical direction.

Further, in the above embodiment, the motor 8 is incorporated in the supporting side portion, but the motor 8 may be incorporated in the driven side, that is, inside the second arm 3.

Effects of the Invention In the present invention, a stator is integrally formed on one part of the joint part, and a ring-shaped magnet is fixed as a rotor to the central axis on the other side, so that it can be directly driven by the component parts of the robot. A part of the motor can be used for the same purpose, so the structure of the joint part can be simplified. Furthermore, fins are formed on the outer periphery of the stator, which efficiently dissipates the heat generated by the motor to the outside, so there is no thermal accumulation in the joints, and therefore there is no adverse thermal effect, especially thermal expansion of the rotating parts. , it is possible to prevent adverse thermal effects on nearby electronic circuits, etc.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of the first arm and second arm of the robot, FIG. 2 is a vertical sectional view of the second arm, and FIG. 3 is a horizontal sectional view of the second arm. 1. Horizontal articulated robot, 2. First arm, 3
...Second arm, 4.Direct drive motor, 5.Motor shaft, 6.Base, 8.Direct drive motor, 9.
・Casing, lO・・Fin, 11・・Center shaft, 13
...Magnet, 14...Stator, 16...Cooling fan,
17...Motor unit for cooling, 18...Vertical movement axis,
19.20...Motor. Patent applicant Sankyo Seiki Seisakusho Co., Ltd.
Patent Attorney Kunio Nakagawa Figure 7 Figure 2 Figure 3

Claims (1)

[Claims] In a joint part of a robot that rotatably supports a driven side relative to a supporting side, a ring-shaped magnet is fixed to a central axis integral with one side, a stator is fixed inside the other side surrounding the magnet, and the other side is fixed to a central axis. A robot joint having cooling fins formed on the outside of the side.