JPH05296308A - Rectilinearly advancing/rotating actuator - Google Patents

Abstract

PURPOSE:To realize a rectilinear/rotary movement with simple structure composed of one set of ball/nut and two motors, in a rectilinear/rotary actuator to drive a machine such as a theta-Z table or robot needed to make a rectilinear and rotary movement. CONSTITUTION:A rectilinear/rotary actuator composed of two motors, and a ball screw and a nut, comprises the nut 3 fixed to a rotor 8 of a first one of the motors provided on the output shaft, the ball screw 2 fitted to the nut 3, and a spline 11 provided on an end portion of the ball screw 2 located on a side opposite to the other end thereof where an output shaft 1 is located. The actuator further comprises a hollow shaft 13 formed, at its inside diameter surface, with a groove 12 fitted to that spline 11, a rotor 14 of a second motor thereof fixed to the hollow shaft 13, and a bracket 16 for integrating a stator 7 of the first motor and 5 stator 17 of the second motor with each other. Retention and drive of the first motor and the second motor of the rectilinearly advancing/rotating actuator are selectively controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear / rotary actuator for driving a machine such as a .theta.-Z table or a robot which requires linear and rotary motions.

[0002]

2. Description of the Related Art Conventionally, as a device that selectively or simultaneously performs linear motion and rotary motion, first and second rotary members are arranged in series so as to be rotatable about the same central axis, and a controlled shaft is provided on both rotary members. Support, and an X-shaped ball groove is provided on the controlled shaft, and a first rotating member having a ball nut cut into a right-hand thread, for example, is rotatably fitted in this groove, and the second rotation is performed. The threaded groove of the ball nut installed in the member is cut with the ball nut installed in the first rotating member in the direction opposite to the groove cutting direction (for example, left-hand thread), and is fitted to the gear device and two sets. There is one in which a first motor and / or a second rotary member are mutually rotated by an electric motor to generate a linear motion and a rotary motion (for example, Japanese Patent Publication No. 2-47620).

[0003]

However, in the prior art, since the gear device and the two-type electric motor are mounted outside this mechanism, the mechanism is complicated and large in size. Therefore, an object of the present invention is to provide a rectilinear / rotary actuator that can realize linear / rotational motion with a simple configuration using one ball / nut and two motors.

[0004]

In order to solve the above-mentioned problems, in a linear movement / rotation actuator consisting of two motors, a ball screw and a nut, the first one provided on the output side.
Nut 3 fixed to the rotor 8 of the motor, a ball screw 2 fitted to the nut 3, a spline 11 provided at an end of the ball screw 2 opposite to the output shaft 1, and a spline 11 fitted to the spline 11. Hollow shaft 1 with a groove 12 formed on the inner diameter side
3 and a rotor 14 of the second motor fixed to the hollow shaft 13, and a bracket 16 that integrates the stator 7 of the first motor and the stator 17 of the second motor together to form a rectilinear / rotary actuator. Constitute. The holding and driving of the first motor and the second motor of the linear movement / rotation actuator having the above configuration are selectively controlled.

[0005]

(A) When the rotor 14 of the second motor is held and the rotor 8 of the first motor is rotated, the ball screw 2 becomes
The hollow shaft 13 is guided by the groove 12 and goes straight. (B) When the rotor 8 of the first motor is held and the rotor 14 of the second motor is rotated, the hollow shaft 13 is rotated, and the ball screw 2 forms a groove 12 provided in the inner diameter of the hollow shaft 13. The spline 11 goes straight while rotating while keeping the mesh.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A concrete embodiment of the present invention will be described below with reference to FIG. The output shaft 1 is formed at the end of a very standard single lead ball screw 2. The nut 3 of the ball screw 2 is fitted into the ball screw 2. The outer periphery of the nut 3 is supported with high rigidity by a double-row angular bearing 5 and the like via a housing 4. A linear guide mechanism such as a spline 11 is provided at the end of the ball screw 2 opposite to the output shaft 1. The bearing 5 is fixed to the stator 7 of the first motor via the bracket 6. A rotor 8 of the first motor 7 is arranged on the inner diameter side of the stator of the first motor 7 with a gap therebetween. Further, the inner diameter side of the rotor 8 of the first motor 7 is fixed to the cup-shaped hub 9. The nut 3 is fixed to the rim portion 10 of the cup-shaped hub 9, and the nut 3 is rotated. The spline 11 provided at the end of the ball screw 2 that is fitted with the nut 3 on the side opposite to the output shaft 1 is fitted with the groove 12 provided on the inner surface of the hollow shaft 13 having a length corresponding to the stroke of the ball screw 2. To do. The ball screw 2 slides in the hollow shaft 13 in the axial direction. The rotor 14 of the second motor is fixed to the outer diameter side of the hollow shaft 13. Both ends of the hollow shaft 13 are rotatably supported by bearings 15. The bearings 15 and 15 are fixed to the stator 17 of the second motor via the brackets 16 and 18. The outer diameter side of the bracket 16 is fixed to the stator 7 of the first motor, and the stator 7 of the first motor and the stator 17 of the second motor are integrated. The first motor and the second motor may be any one of an induction motor, a DC motor, and a synchronous motor, but a pulse motor that can easily hold itself is desirable. Below, the operation | movement in the case of performing only straight advance of the ball screw 2 and performing a straight advance and rotation simultaneously is demonstrated. (A) In the case of performing only the straight-ahead operation: The winding of the stator 17 of the second motor is energized to hold the rotor 14 of the second motor. As for the holding method, in the case of an induction motor and a DC motor, dynamic stop control may be performed, and in the case of a synchronous motor and a pulse motor, self-holding may be performed. Next, the winding of the stator 7 of the first motor is energized, the rotor 8 of the first motor is rotated, and the nut 3 fixed to the rotor 8 is rotated. Then, the ball screw 2 is restrained from rotating by the groove 12 provided in the hollow shaft 13 of the second motor, so that the hollow shaft 13
Sliding inside in the axial direction. Ball screw 2 travels in the first direction
It is controlled by the rotation direction of the motor. (B) In the case of simultaneously traveling straight and rotating When the winding of the stator 7 of the first motor is energized and the rotor 8 of the first motor is held, the nut 3 fixed to the rotor 8 is held. .. The method of holding the rotor 8 is the same as in the case of (a). Next, the winding of the stator 17 of the second motor is energized to rotate the rotor 14 of the second motor.
Then, the hollow shaft 13 rotates and the hollow shaft 13
The ball screw 2 is rotated while the groove 12 provided in the inner diameter of the and the spline 11 are engaged with each other. Since the rotation of the nut 3 is restricted, the ball screw 2 follows the lead of the nut 3 and simultaneously rotates and goes straight. Therefore, (a),
By selectively controlling (b), it is possible to realize an actuator that performs only straight movement and simultaneously performs straight movement and rotation.

[0007]

Since the two types of drive motors are integrally and serially arranged and the ball screw having a single lead is housed in the rotor of the drive motor, the structure can be simplified. Further, by selecting holding and driving of the two types of drive motors, it is possible to easily realize an actuator that performs only straight movement and simultaneously performs straight movement and rotation.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 1 Output Shaft 2 Ball Screw 3 Nut 4 Housing 5, 15 Bearing 6, 16, 18 Bracket 7 First Motor Stator 8 First Motor Rotor 9 Hub 10 Rim Part 11 Spline 12 Groove 13 Hollow Shaft 14th Second motor rotor 17 Second motor stator

Claims (3)

[Claims] 1. A nut 3 fixed to a rotor 8 of a first motor provided on an output side in a rectilinear / rotary actuator composed of two motors and a ball screw and a nut,
A ball screw 2 fitted with the nut 3, a spline 11 provided at an end of the ball screw 2 opposite to the output shaft 1, and a hollow shaft 13 having a groove 12 fitted with the spline 11 cut on the inner diameter side. , The second fixed to this hollow shaft 13
A straight-moving / rotating actuator comprising a rotor 14 of the motor, a bracket 16 that integrates the stator 7 of the first motor and the stator 17 of the second motor. 2. The rectilinear / rotary actuator according to claim 1, wherein the ball screw 2 is moved straight by holding the rotor 14 of the second motor and rotating the rotor 8 of the first motor. 3. Holding the rotor 8 of the first motor,
By rotating the rotor 14 of the second motor,
The ball screw 2 is allowed to move straight and rotate simultaneously.
The linear / rotation actuators described.