JP2010220393A - Rotary actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary actuator having a function for autonomous return when a ball screw in a ball screw mechanism is rotated and moved in the axial direction to a ball nut. <P>SOLUTION: The rotary actuator rotatably includes a rotor 25 including permanent magnets in a stator 17. In the rotary actuator, a screw 7 for moving a rotating shaft 11 in the axial direction is mounted on the rotating shaft 11 integrally provided with the rotor 25, and the length in the axial direction of the stator 17 and the length in the axial direction of a part including the permanent magnets for the rotor 25 are equalized. In the rotary actuator, a slider 37 relatively rotatable to the rotating shaft 11 and integrally reciprocatable in the axial direction to the rotating shaft 11 is mounted at the front end of the rotating shaft 11, and a pushing piece 39 for pushing a body to be worked is suitable for the slider 37. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotary actuator such as a motor, and more particularly, to a rotary actuator provided with a rotatable rotor so as to be movable in an axial direction.

  2. Description of the Related Art Conventionally, there is a configuration in which a motor and a ball screw are combined as a drive device that moves a ram up and down in a press machine (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-207560

  The configuration of the driving device described in Patent Document 1 is a configuration in which a rotor in a motor is configured in a cylindrical shape, and a ball screw is screwed into a ball nut integrally provided on the inner peripheral surface of the rotor so as to be movable in the axial direction. It is. That is, since the conventional configuration is such that the ball nut in the ball screw mechanism is rotated, there is a problem in that the rotating portion becomes large and inertia increases.

  The present invention has been made in view of the problems as described above, and is a rotary actuator in which a rotor provided with a permanent magnet is rotatably provided in a stator, and a rotary shaft provided integrally with the rotor, A screw portion for moving the rotating shaft in the axial direction is provided, and the axial length of the stator is configured to be equal to the axial length of the portion of the rotor including the permanent magnet. It is a feature.

  In addition, a rotary actuator provided with a rotor provided with a permanent magnet in a stator so as to be rotatable, and a screw part for moving the rotary shaft in the axial direction on a rotary shaft provided integrally with the rotor. And the axial length dimension of the portion of the rotor including the permanent magnet is shorter than the axial length dimension of the stator.

  Further, in the rotary actuator, a rotating body provided on the rotating shaft so as to be relatively movable in the axial direction and rotatable integrally therewith includes a rotation detecting means for detecting the rotation of the rotating shaft. It is characterized by.

  The rotary actuator includes a slider at the tip of the rotary shaft that is rotatable relative to the rotary shaft and reciprocally movable integrally with the rotary shaft in an axial direction. It has a pressing element for pressing the body.

  According to the present invention, since the rotary shaft in the rotary actuator is configured to rotate and move in the axial direction, the diameter of the rotating portion can be reduced and inertia can be suppressed. In addition, by making the axial length of the stator equal to the axial length of the portion of the rotor having the permanent magnet, a self-return function is produced after the rotor has moved in the axial direction. It is possible to improve.

It is a section explanatory view showing the composition of the rotary actuator concerning a 1st embodiment of the present invention. It is explanatory drawing which shows the operation state of a rotary actuator same as the above. It is a section explanatory view showing the composition of the rotary actuator concerning a 2nd embodiment of the present invention.

  Hereinafter, a rotary actuator according to an embodiment of the present invention will be described with reference to the drawings. The rotary actuator can be used by being mounted on various machines such as machine tools and industrial machines. Is illustrated and described for a case where it is applied to a punch press as an example of a press machine.

  Referring to FIG. 1, a rotary actuator 1 according to an embodiment of the present invention is attached to a frame 3 in a press machine. More specifically, a cylindrical support housing 5 is detachably attached to the frame 3 via a fixture (not shown) such as a mounting bolt, and a screw portion is formed in the support housing 5. A ball nut 9 in the ball screw mechanism 7 is inserted and supported. A ball screw 11 is screwed into the ball nut 9 via a ball so as to be rotatable and movable up and down. The ball screw 11 penetrates the ball nut 9 in the vertical direction.

  A motor portion 13 for rotating a ball screw 11 as a rotation shaft is provided on the upper portion of the support housing 5. That is, a stator (laminated steel plate) 17 having an exciting coil 15 is integrally attached to the upper portion of the support housing 5 via upper and lower stator brackets 19 and 21. A rotor (laminated steel plate) 25 is integrally attached by a fixture 27 such as a nut to an upward extending portion 23 that extends upward of the ball screw (rotating shaft) 11. Like a general motor, a plurality of permanent magnets (not shown) are provided. In the motor unit 13, the axial length of the stator 17 and the axial length of the portion of the rotor 25 provided with the permanent magnets, that is, the lamination dimensions of the laminated steel plates are as shown in FIG. They are equally configured.

  The upper end portion of the upward extending portion 23 of the rotating shaft 11 is provided with a spline portion 29 that is long in the upward direction. The spline portion 29 is a rotating body that is rotatably provided on the upper stator bracket 19. The spline nut 31 is penetrated so as to be relatively slidable. That is, the spline nut (rotary body) 31 is configured to rotate integrally with the rotary shaft 11. The spline nut 31 is provided with a rotation detection means 33 such as a rotary encoder for detecting the rotation of the rotary shaft 11. Therefore, when the motor unit 13 is rotationally driven, the rotational speed, rotational position, rotational speed, and the like of the rotating shaft 11 can be detected.

  A plurality of guide posts 35 are vertically provided on the lower surface of the support housing 5, and a slider 37 is provided on the guide post 35 so as to be movable up and down. In order to smoothly move the slider 37 up and down, the weight of the slider 37 and the like is supported by a known appropriate balancer (not shown) such as a spring. The slider 37 is provided with a pressing member 39 such as a ram for striking or pressing a punch (upper die) as an actuated body in a press machine. In this embodiment, the pressing element 39 is attached to the slider 37 via an overload safety device 43 having a shear plate 41. Since the configuration of the overload safety device 43 is a known configuration, a more detailed description of the overload safety device 43 is omitted.

  In order to move the slider 37 up and down along the guide post 35, the rotary shaft 11 and the slider 37 are connected to each other so as to be relatively rotatable and integrally movable up and down. In other words, a semicircular spherical recess 45 is formed on the upper surface of the slider 37, and a spherical portion 47 provided at the lower end of the rotary shaft 11 is relatively rotatably engaged with the recess 45. is there. A ball pressing member 49 for preventing the spherical portion 47 from being detached from the concave portion 45 is attached to the slider 37.

  In the configuration as described above, when the exciting coil 15 in the motor unit 13 is excited and the motor unit 13 is driven to rotate in the forward direction, the ball screw (rotating shaft) 11 is driven to rotate in the forward direction. That is, since the ball screw 11 in the ball screw mechanism 7 is driven to rotate in the forward direction, the diameter of the rotating portion can be suppressed to a smaller diameter compared to the case where the ball nut 9 in the ball screw mechanism 7 is driven to rotate in the forward direction. It can be suppressed. Therefore, the response of acceleration / deceleration of the rotating part can be improved.

  When the rotating shaft (ball screw) 11 is rotated forward as described above, the rotating shaft 11 is moved downward by the action of the ball screw mechanism 7 and the slider 37 is integrally lowered. Therefore, the pressing element 39 provided in the slider 37 is lowered to hit or press the upper die in the press machine.

  When the upper die is pressed or pressed and then the excitation coil 15 in the motor unit 13 is excited to drive the motor unit in reverse rotation, the ball screw mechanism 7 causes the rotary shaft 11 to move upward while being driven in reverse rotation. Then, the slider 37 is raised integrally, and the presser is also lifted to complete the processing. At this time, the rotor 25 is returned to the original raised position.

  As described above, when the rotating shaft 11 is lowered, the rotor 25 is also lowered integrally. Therefore, the positional relationship of the rotor 25 with respect to the stator 17 is lowered by the stroke S as shown in FIG. Deviation occurs in the direction. Therefore, the range where the stator 17 and the rotor 25 face each other is T. Therefore, the attracting action of the permanent magnet provided in the rotor 25 acts on the stator 17, and the rotor 25 receives the attracting force for returning to the original ascending position. The suction force is sufficiently small as compared with the force when the motor unit 13 is driven to rotate and the rotary shaft 11 is moved downward, and does not cause a problem.

  Then, at the time of a power failure or when the power is shut off, the rotary shaft 11 rotates in the reverse direction by the action of the attractive force, and the rotor 25 and the stator 17 are returned to their original ascending positions where they are magnetically balanced. In addition, since the weight of the slider 37 etc. is supported by the balancer, the magnitude | size of the said suction force should just have a magnitude | size which can respond | correspond to the weight of the rotating shaft 11 grade | etc.,. As already understood, in the above-described configuration, when the rotor 25 is lowered with respect to the stator 17, an attractive force that returns the rotor 25 upward by the action of the permanent magnet provided on the rotor 25 acts. It is possible to improve the performance.

  The rotation of the rotary shaft 11 is detected by the rotation detection means 33, and the vertical movement position of the slider 37 from the reference position based on the rotation detection value by the rotation detection means 33 and the pitch of the ball screw mechanism 7. Is detected.

  In the above description, as shown in FIG. 1, the axial length of the stator (laminated steel plate) 17 in the motor unit 13 and the axial length of the rotor (laminated steel plate) 25 are equal to each other. The configuration has been described. However, as shown in FIG. 3, the axial length of the stator 17 can be increased by the length of the stroke S as compared to the axial length of the rotor 25.

  According to the above configuration, the range T in which the stator 17 and the rotor 25 face each other is always equal to the axial length of the rotor 25. Therefore, even when the rotor 25 is lowered by the stroke S, Since the range T facing the rotor 25 is always constant, the rotational force for rotating the rotor 25 is always kept constant.

  In the above configuration, the rotor 25 is normally positioned at a position where the rotor 25 and the stator 17 are magnetically balanced, that is, at an intermediate position in the vertical direction of the stator 17. When the motor unit 13 is rotated forward, the rotor 25 and the rotating shaft 11 are lowered to a position where the lower end portion of the rotor 25 substantially coincides with the lower end portion of the stator 17 by the action of the ball screw mechanism 7. Thereafter, the motor unit 13 is rotated in the reverse direction to return the rotor 25 to the original position, that is, the central portion in the vertical direction of the stator 17, thereby completing one-stroke reciprocation of the rotor 25 and the rotating shaft 11.

  As described above, when the rotor 25 is moved downward from the central portion of the stator 17 in the vertical direction, the magnetic balance between the rotor 25 and the stator 17 is lost, and an attractive force for returning the rotor 25 upward is generated. Compared with the downward thrust of the rotating shaft 11 by the ball screw mechanism 7, it is small and does not cause a problem.

  In the above configuration, at the time of a power failure or power interruption, the rotor 25 and the stator 17 are returned to a magnetically balanced position as in the first embodiment described above, and safety is also improved. It will improve.

  As can be understood from the above description, since the ball screw 11 in the ball screw mechanism 7 is directly driven to rotate by the motor unit 13, compared with the case of rotating the ball nut 9 in the ball screw mechanism 7, It is easy to reduce the diameter, and the response of the rotating part can be improved. In the above configuration, since the ball screw mechanism 7 and the motor unit 13 are stacked in the axial direction, the diameter of the rotor 25 in the motor unit 13 can be reduced, although the length is increased in the axial direction. is there.

  Furthermore, there is a function of returning the rotor 25 to the original position where the stator 17 and the rotor 25 are magnetically balanced, and safety can be improved.

1 Rotary actuator 3 Frame 5 Support housing 7 Ball screw mechanism (screw part)
9 Ball nut 11 Ball screw (Rotating shaft)
13 Motor part 15 Excitation coil 17 Stator 25 Rotor 29 Spline part 31 Spline nut (Rotating body)
33 Rotation detection means 37 Slider 39 Presser 43 Overload safety device

Claims (4)

  A rotary actuator provided with a rotor provided with a permanent magnet in a stator so as to be rotatable, and provided with a screw part for moving the rotary shaft in an axial direction on a rotary shaft provided integrally with the rotor, A rotary actuator characterized in that an axial length dimension of the stator is equal to an axial length dimension of a portion of the rotor having a permanent magnet.   A rotary actuator provided with a rotor provided with a permanent magnet in a stator so as to be rotatable, and provided with a screw part for moving the rotary shaft in the axial direction on a rotary shaft provided integrally with the rotor, A rotary actuator characterized in that an axial length dimension of a portion of the rotor having a permanent magnet is shorter than an axial length dimension of the stator.   3. A rotary actuator according to claim 1, wherein said rotary actuator is configured to detect a rotation of said rotary shaft in a rotary body provided on said rotary shaft so as to be relatively movable in the axial direction and integrally rotatable. A rotary actuator characterized by comprising:   4. The rotary actuator according to claim 1, wherein a slider that is rotatable relative to the rotary shaft and reciprocally integrated with the rotary shaft in an axial direction is provided at a tip of the rotary shaft. A rotary actuator comprising a slider for pressing the actuated body on the slider.

Images