JP3815415B2 - 2-DOF actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a simple two-degree-of-freedom actuator in which a shaft moves and rotates linearly (linearly).
[0002]
[Prior art]
A conventional two-degree-of-freedom actuator will be described in JP-A-6-303737. The two-degree-of-freedom actuator disclosed in the publication includes a drive mechanism having different linear motion and rotational motion mechanisms, and the rotational motion mechanism has a rotational motor inside the rotational motor frame, Power is transmitted to the shaft via the spline guide bearing, and the shaft is rotated by rotation of the rotation motor.
The linear motion mechanism includes a linear motor, a linear bearing and a shaft through a linear motor moving element inside a linear motor frame having an outer cylinder and an inner cylinder, and the shaft using the linear movement of the moving element. Is in a linear motion.
[0003]
When the rotating motor of the two-degree-of-freedom actuator configured as described above is driven, the shaft is rotated by the rotation of the rotor. Next, when the linear motor is driven, the moving element and the linear motor frame move linearly, and the shaft supported via the bearing moves in the linear direction.
According to such a two-degree-of-freedom actuator, when the rotary motor rotates, the linear motor moving element is not affected by the rotating operation, and when the linear motor moves linearly, the rotating motor rotor is linear. Since it is not affected by the moving operation, a highly responsive one can be obtained by reducing the mass of the shaft as compared with the conventional one.
[0004]
[Problems to be solved by the invention]
However, in the linear motion in the two-degree-of-freedom actuator configured as described above, the linear motor frame and the inner cylinder of the linear motor frame integrally move linearly with the linear motor. Compared to moving the linear motor, the thrust of the linear motor increases by the mass of the inner cylinder of the linear motor frame, the structure becomes complicated, and there are two types of rotary motor and linear motor. Therefore, there was a problem that the types of motors increased.
[0005]
The present invention has been made to solve the above-described problem, and provides a two-degree-of-freedom actuator that is configured simply with a linear motor and that allows the shaft to linearly and rotate without operating the linear motor frame. It is intended.
[0006]
[Means for Solving the Problems]
A two-degree-of-freedom actuator according to the present invention includes a first linear motor having a first stator and a first moving element disposed facing the inner side of the first stator, and the first linear motor. A second linear unit provided on a straight line with the linear motor, and provided with a second stator and a second moving element which is disposed to face the inner side of the second stator and has a hollow portion at the center. A motor, a nut inserted and fixed in the hollow portion of the second moving element, and a screw are provided, and the screw is screwed into the nut, and the central portion of the first moving element And when the shaft is moved linearly, the first and second linear motors are driven, and when the shaft is rotated, the first linear motor is stopped. And a control means for driving the second linear motor. And it is characterized in and.
According to such a two-degree-of-freedom actuator, when the first and second linear motors are driven to cause the first and second moving elements to linearly move, the shaft moves linearly by the first and second moving elements.
When the second linear motor is driven to operate the second moving element while the first linear motor is stopped, the nut screwed to the shaft is rotated by the movement of the second moving element, and the shaft And the first moving element fixed to the shaft rotates.
Therefore, cases other than the first and second moving elements do not move with the linear movement of the shaft, and therefore the thrust of the first and second linear motors can be minimized. In addition, since the two-degree-of-freedom actuator can be configured with only the first and second linear motors, there is an effect that the configuration is simple and the types of motors can be reduced.
[0007]
Further, by providing synchronization means for linearly moving the first and second moving elements in synchronization, driving the first and second linear motors to operate the first and second moving elements, The shaft can be prevented from rotating while moving linearly.
Therefore, when the electronic component is attached to the substrate by a hand connected to the shaft, etc., after the hand is moved linearly, the hand rotates by changing the direction of the electronic component by rotating the shaft to the substrate. Suitable for mounting applications.
[0008]
Furthermore, if the first and second linear motors and the integrated case for housing the shaft are provided, the case of the two-degree-of-freedom linear actuator can be integrated, and there is an effect that the size and weight can be reduced.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view illustrating a two-degree-of-freedom actuator according to an embodiment of the present invention.
In FIG. 1, a two-degree-of-freedom actuator 100 includes first and second linear motors 3 and 10 that drive a shaft 15, and a position detection unit 20 that detects a linear position of the shaft 15 when the shaft 15 is linearly driven. And a control unit 50 that controls the driving of the first and second linear motors 3 and 10 and a cylindrical drum-shaped case (housing) 2 having an upper lid 2a and a lower lid 2c. . A hole is formed in the center of the upper lid 2a and the lower lid 2c.
[0010]
The case 2 includes a first stator 3f having a cylindrical shape and a first mover 3L that is arranged to face the inside of the first stator 3f and moves linearly in a cylindrical shape. The linear motor 3, the ring 5 inserted and fixed in the hollow portion of the first moving element 3L, the first linear motor 3 and a linear second stator 10f and the second linear stator 3 are provided. A second linear motor 10 having a cylindrical second moving element 10L that is arranged to face the inner side of the two stators 10f and linearly moves in a cylindrical shape, and a cylindrical shape of the second moving element 10L. A nut 12 inserted and fixed in the hollow portion, a screw 15n screwed into the nut 12, and a shaft 15 fixed to the ring 5, supporting both ends of the shaft 15, and an upper lid 2a, Bearings 17 respectively fixed to the lower lid 2c And a 19. The range of the screw 15n of the shaft 15 is provided in a portion where the second moving element 10L moves the second stator 10f. However, if the rotation amount of the shaft 15 is small, the range can be shortened.
[0011]
The control unit includes a micro computer 50. The micro computer 50 is connected to an output of the position detection unit 20 and an input interface 52 (hereinafter referred to as “I / F”) to which an operation command is input, and a CPU 54. , ROM 56, RAM 57, voltage generation control unit A58, and output I / F 60 connected to voltage generation control unit B59. The RAM 57 is formed so as to provide a work area to the CPU 54.
[0012]
When a linear operation command for linearly moving the shaft 15 is input to the ROM 56, the first and second linear motors 3 and 10 are driven to linearly move the shaft 15.
When a rotation operation command for rotating the shaft 15 is input to the input I / F 52, the first linear motor 3 is stopped and the second linear motor 10 is driven to rotate the shaft 15. Furthermore, when the synchronization command and the linear operation command are input to the input I / F 52, the above three types of operation programs are performed in which the first and second linear motors 3 and 10 are driven in synchronization to move the shaft 15 linearly. Is stored. The synchronization includes start, stop, speed, and distance.
[0013]
The position detection unit 20 has a scale 15s in which ring-shaped N and S magnetic poles are alternately formed at the upper end of the shaft 15, and is determined in advance by a Hall element 22 facing the scale 15s. The CPU 54 counts the number of N and S magnetic poles from the reference point so that the linear movement amount of the shaft 15 is obtained.
Note that the rotation angle of the shaft 15 is not detected. This is because the shaft 15 is predetermined by applying one pulse to the second stator 10f by generating the voltage value and pulse width of the pulse voltage generated from the voltage generation control unit B59 as predetermined. This is because the CPU 54 can determine the rotation angle θ of the shaft 15 by counting the number of pulses generated by the command from the voltage generation control unit B59.
[0014]
The operation of the two-degree-of-freedom actuator configured as described above will be described with reference to FIGS. 2 is a cross-sectional view showing the linear motion of the shaft of the two-degree-of-freedom actuator, and FIG. 3 is a cross-sectional view showing the rotational motion of the shaft of the two-degree-of-freedom actuator.
Now, a linear operation command for linearly moving the shaft 15 by a predetermined distance while synchronizing the first and second linear motors 3 and 10, and the first and second movers 3L and 10L are moved by the same distance at the same speed. When the synchronization command to be input is input, the CPU 54 takes the linear operation command and the synchronization command in accordance with the procedure stored in the ROM 56, that is, the voltage generation control units A58 and B59 via the output I / F 60 first and first. 2 linear motors 3 and 10 are driven synchronously.
[0015]
By such driving, the first and second movable elements 3L and 10L move downward as shown in FIG. 2, so that the shaft 15 fixed to the first movable element 3L also linearly moves downward. The CPU 54 detects the N and S magnetic poles applied to the scale 15s by the Hall element 22 and calculates the amount of movement of the shaft 15 by integrating the number of the N and S magnetic poles, and when the movement distance of the linear operation command is reached. Then, a stop command is issued, the output I / F 60, and the voltage generation control units A58 and B59 cut off the current flowing through the first and second stators 3f and 10f, thereby causing the first and second linear motors 3 and 10 to Stop. The thrust generated in the shaft 15 during linear movement is the sum of the thrust generated by the first and second moving elements 3L and 10L.
[0016]
Now, when a linear operation command and a synchronization command for rotating the shaft 15 by a predetermined number of revolutions are input, the CPU 54 takes in the linear operation command and the synchronization command and follows the procedure stored in the ROM 56, that is, outputs the I / F 60. Accordingly, the first linear motor 3 is stopped by the voltage generation control units A58 and B59, and the second linear motor 10 is driven.
When the first moving element 3L is stopped by such driving, the second moving element 10L and the nut 15 move downward as shown in FIG. 3, whereby the screw 15n of the shaft 15 screwed into the nut 12 turns. Then, the shaft 15 also rotates. Along with this, the first moving element 3L fixed to the shaft 15 also rotates.
[0017]
The CPU 54 can detect the rotation angle θr of the shaft 15 by counting the pulses generated from the voltage generation control unit B59 as described above. Accordingly, when the predetermined count number is reached, a stop command is issued, and the current that is flowing through the second stator 10f is cut off by the voltage generation control unit B59 via the output I / F 60, so that the second linear motor 10 To stop.
The thrust generated when the shaft 15 rotates is the thrust generated by the second moving element 10L.
[0018]
According to the above two-degree-of-freedom actuator 100, when an electronic component is attached to the substrate by a hand or the like (not shown) connected to the shaft 15, the electronic component is gripped by the hand (not shown) and the shaft 15 This is suitable for the purpose of attaching the electronic component to the substrate by rotating the shaft 15 and rotating the hand (not shown).
[0019]
Embodiment 2. FIG.
When rotating the shaft 15 of the two-degree-of-freedom actuator 100 while performing a linear motion, the first moving element 3L of the linear motor 3 and the second moving element 10L of the linear motor 10 are operated asynchronously. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a two-degree-of-freedom actuator according to an embodiment of the present invention.
2 is a cross-sectional view showing a linear motion (linear motion) of a shaft of the two-degree-of-freedom actuator shown in FIG.
3 is a cross-sectional view showing the rotational movement of the shaft of the two-degree-of-freedom actuator shown in FIG.
[Explanation of symbols]
2 case, 3 first linear motor, 3f first stator, 3L first mover, 10 second linear motor, 10f second stator, 10L second mover, 15 shaft, 20 position Detection unit, 100 2-degree-of-freedom actuator.

Claims (3)

A first linear motor having a first stator and a first moving element disposed facing the inner side of the first stator;
The first linear motor is provided in a straight line, and is provided with a second stator and a second moving element that is disposed to face the inside of the second stator and has a hollow portion in the center. A second linear motor;
A nut inserted and fixed in the hollow portion of the second mover;
A shaft provided with a screw, the screw being screwed onto the nut, and a shaft fixed to a central portion of the first movable element;
When the shaft is moved linearly, the first and second linear motors are driven,
When rotating the shaft, the first linear motor is stopped and the control means for driving the second linear motor;
A two-degree-of-freedom actuator comprising: Synchronizing means for linearly moving the first and second moving elements synchronously,
The two-degree-of-freedom actuator according to claim 1, further comprising: The first and second linear motors, and the case that is integrated with the shaft,
The two-degree-of-freedom actuator according to claim 1, wherein the two-degree-of-freedom actuator is provided.

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