JPH03285595A - Rotation driving device - Google Patents

Abstract

PURPOSE:To obtain a high torque with an inexpensive constitution without employing an expensive rare earth magnet by providing a field generating coil on rotor side to connect it to a power supply through wires and generating a field by conducting current through the coil. CONSTITUTION:A rotor 5 is provided with a plurality of field generating coils 6 on the outer peripheral surface in the direction of the circumference thereof. A plurality of stator coils 7 of phases U, V, W are arranged sequentially around the rotor 5. The field generating coils 6 on the rotor 5 side are connected directly to a power supply through wires. The wires are arranged with enough margin so as to allow the rotor 5 to be turned within the rotating range of 360 deg. while the wires are guided properly by guides if necessary. The field generating coil 6 and the stator coil 7 are controlled by a driver unit 9 so as to generate a rotary field in accordance with the rotating position of the rotor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a servo-type rotary drive device using a DC power supply, and particularly to a rotary drive device suitably applicable to direct drive type robots and indexing devices.

BACKGROUND OF THE INVENTION Conventionally, brushless DC servo motors are often used to drive robot arms and indexing devices using a direct drive method.

In this brushless DC servo motor, as shown in FIG. 4, permanent magnets 22 made of rare earth are arranged around the outer periphery of the rotor 21 so as to alternately have different polarities.
A plurality of stator coils 23 are arranged around the outer periphery of the rotor 21, and a rotating magnetic field is generated by passing three-phase alternating current of U phase, ■ phase, and W phase through each stator coil 23.
is configured to rotate.

In this way, by using the rare earth magnets 22 in the rotor 21, a large torque can be obtained with a compact configuration.

Problems to be Solved by the Invention However, there are problems in that rare earth magnets are expensive, resulting in high costs, and that a sufficiently large torque cannot be obtained.

SUMMARY OF THE INVENTION In view of the above conventional problems, it is an object of the present invention to provide an inexpensive rotary drive device for direct drive in robots and indexing devices.

Means for Solving the Problems In order to achieve the above object, the rotary drive device of the present invention includes a rotor having a plurality of magnetic field generating coils arranged in the circumferential direction, and a plurality of stator coils arranged around the rotor. , a fixed power supply connection part connected to each magnetic field generating coil of the rotor by an electric wire, a driver part that supplies current to each stator coil so as to generate a rotating magnetic field, and a rotational position detection means of the rotor; The present invention is characterized by comprising a control section that controls the driver section based on a rotational position signal and a position command signal.

Function The rotary drive device of the present invention has a rotation range of 3 for direct drive motors in robots and indexing devices.
Focusing on the fact that it is limited to about 60 @, current is supplied from a fixed power supply connection to the rotor's magnetic field generation coil through an electric wire to generate a magnetic field on the rotor side. The rotor can be rotationally driven by passing a predetermined current from a driver section to each stator coil while generating a magnetic field in the coil to generate a rotating magnetic field corresponding to the rotational position of the rotor. (Since the rotor side also generates a magnetic field with a coil, there is no need to use expensive rare earth magnets, and it is possible to construct the rotor at low cost and obtain high torque.

EXAMPLE Hereinafter, an example in which the present invention is applied to a motor for swinging the arm of a robot using a direct drive method will be described with reference to FIGS. 1 to 3.

As shown in FIG. 3, the motor 1 of this embodiment is arranged at a joint 3 of a robot 2, and rotates the arm 4 so as to directly swing the corresponding arm 4 within a rotation range of 360° or less. The rotor shaft is directly connected to the shaft.

In this motor 1, as shown in FIG. 1, a plurality of magnetic field generating coils 6 are provided on the outer peripheral surface of a rotor 5 in the circumferential direction. Further, around this rotor 5, a plurality of stator coils 7 of U-phase, ■-phase, and W-phase are arranged in sequence. The magnetic field generating coil 6 on the rotor 5 side is directly connected to a power supply connection part (not shown) provided at an appropriate location on the outer shell of the motor 1 by an electric wire (not shown) without using a brush. The electric wires are routed with a margin to allow the rotor 5 to rotate within a rotation range of 360 degrees, and are guided by appropriate guides as necessary. Also,
The lead wires of each stator coil 7 are also connected to power supply connections (not shown) provided at appropriate locations on the outer shell.

Current is supplied to the magnetic field generating coil 6 and the stator coil 7 by a drive circuit as shown in FIG. In FIG. 2, 8 is a DC power supply, and 9 is a driver section. This driver section 9 includes a power transistor 10 that controls the drive current value, and power transistors lla to llf that flow a predetermined alternating current to each stator coil 7 so as to generate a rotating magnetic field corresponding to the rotational position of the rotor 5. established,
It is configured to control the energization of each stator coil 7. On the other hand, each magnetic field generating coil 6 is directly connected in parallel or in series to a DC power source 8, and by alternately reversing the winding direction of adjacent magnetic field generating coils 60, magnetic fields of opposite polarity are alternately generated. It is configured as follows. 12 is an encoder for detecting the rotational position of the rotor 5;
3 is a Hall element, and each detection signal is sent to the control unit 1.
4 is entered. Further, a position command signal is input to the control section 14. In the control unit 14, the Hall element 13
The power transistors lla to llf are controlled according to the rotational position of the rotor 5 based on the detection signal from the encoder 12, and the power transistor 10 is controlled based on the detection signal and the position command signal from the encoder 12, so that the rotation of the motor 1 is controlled. Configured to control position.

According to the above configuration, a current is supplied to the magnetic field generating coil 6 provided on the rotor 5 through the electric wire from the power supply connecting portion connected to the DC power source 8, and a magnetic field on the rotor 5 side is generated.

In this state, the power transistor 10 of the driver section 9 is controlled by the control section 14 based on the position detection signal and the position command signal from the encoder 12, and the power transistor 10 of the driver section 9 is controlled according to the rotational position of the rotor 5 detected by the Hall element 13. In the control section 4, each power transistor 11a of the driver section 9 is
~llf is controlled, a predetermined current flows through each stator coil 7, a rotating magnetic field corresponding to the rotational position of the rotor 5 is generated, the rotor 5 rotates, and the rotational position of the rotor 5 matches the commanded position. The rotor 5 is driven to rotate as shown in FIG.

In this way, by using the magnetic field generating coil 6 in the rotor 5, there is no need to use expensive rare earth magnets, the motor 1 can be constructed at low cost, and the output can be easily increased by about three times. .

Effects of the Invention According to the rotary drive device of the present invention, as is clear from the above explanation, a magnetic field generating coil is also provided on the rotor side, and a magnetic field is generated by passing an electric wire through the coil, so that the rotary drive device is brushless. In addition, there is no need to use expensive rare earth magnets in the rotor, and as a result, the rotor can be constructed at a lower cost and even higher torque can be obtained.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention. Figure 1 is a conceptual diagram of the rotor and stator of a brushless DC servo motor, Figure 2 is a drive circuit diagram of the motor, and Figure 3 is a diagram of the motor. FIG. 4 is a conceptual diagram of the rotor and stator of a conventional brushless DC servo motor. ■・・・Motor 5・・・Rotor 6・・・Magnetic field generating coil 7・・・Stator coil 8・・・DC power supply 9-・・・・・・・Driver section 12... Encoder 13... Hall element 14... Control section

Claims (1)

[Claims] A rotor with a plurality of magnetic field generating coils arranged in the circumferential direction, a plurality of stator coils arranged around the rotor, a fixed power supply connection part connected to each magnetic field generating coil of the rotor with an electric wire, and each A driver unit that supplies current to the stator coil to generate a rotating magnetic field, a rotor rotational position detection means, and a control unit that controls the driver unit based on a rotational position signal and a position command signal. A rotary drive device featuring: