JP2005323467A - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear actuator which can have both a direct-acting function and a rotating function and can surely detect a moving member by a positioning sensor, even if the moving member reciprocates, and can avoid the enlargement in its simple constitution. <P>SOLUTION: A rotating unit 40, which is rotatable around an axis on the same axis as the moving member, is coupled with a moving member 13. For the rotating unit 40, its rotating shaft 42 is coupled via a ball bearing 41 to the side 13b of the head shaft of the moving member 13, within an actuator part 11. For the rotating shaft 42, a bearing retainer 43 reversed-U-shaped in cross section is extended to the head shaft side 13b of the moving member 13, and the head shaft side 13b is press-fitted in the inner ring of the ball bearing 41 retained within the bearing retainer 43 thereby being coupled on the same axis as the moving member 13 and coupled with a rotor 45 for a motor via a direct-acting bearing 44. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a linear actuator.

  Linear actuators are used as compressor motors and the like because they can be driven with little loss by resonating together with a spring. And since the compressor using this linear actuator can exhibit excellent performance such as high efficiency, it is expected to be used in various applications for refrigerators, freezers, and air conditioners.

The linear actuator has a structure in which the movable coil type is driven by the force generated in the coil by passing a current through the coil in the magnetic field created by the permanent magnet, or the movable coil type permanent magnet is replaced with the coil. There is a so-called movable magnet type in which a mover including a permanent magnet moves. For example, an actuator of a type in which a coil is provided in a yoke has been proposed (for example, see Patent Document 1).
JP 2003-339147 A (page 2-3, FIG. 1 to FIG. 6)

The prior art of the linear actuator is shown in FIG.
In FIGS. 1A and 1B, reference numeral 10 denotes a linear actuator 10 and 11 denotes an actuator portion thereof. As shown in FIG. 7A, the actuator unit 11 has a yoke (stator) 12, a mover 13 provided in a reciprocating manner inside the yoke 12, and an axially fixed to the yoke 12. A pair of permanent magnets 14 and 15, a pair of permanent magnets 16 and 17 fixed to the yoke 12 corresponding to the permanent magnets 14 and 15, and two coils (not shown) fixed to the yoke 12. I have.
The pair of permanent magnets 14 and 15 are provided opposite to each other on the circumferential surface of the mover 13 in a state of being adjacent to each other in the axial direction, and magnetic poles are arranged perpendicular to the moving direction of the mover 3. The yoke 12 is provided with the magnetic poles arranged in reverse.

The pair of permanent magnets 16, 17 are aligned with the pair of permanent magnets 14, 15 in the moving direction of the mover 13, and face the circumferential surface of the mover 13 in a state of being adjacent to each other in the moving direction. In addition, the magnetic poles are arranged perpendicular to the moving direction of the mover 13, and the magnetic poles are arranged on the yoke 12 with the arrangement of the magnetic poles reversed.
The pair of permanent magnets 14, 15 and the pair of permanent magnets 16, 17 have opposite magnetic poles that are opposed to the mover 13 by permanent magnets that are aligned in the moving direction of the mover.

The linear actuator 10 applies an alternating current (sine wave current, rectangular wave current) to a coil (not shown) to generate a magnetomotive force in the yoke 12 and generates a magnetic flux in a direction corresponding to the direction of the magnetomotive force. Thus, the movable element 13 moves in the yoke 12 along the axial direction in the right direction or in the left direction.
That is, the direction of the magnetic flux generated between the yoke 12, the pair of permanent magnets 14 and 15, the pair of permanent magnets 16 and 17, and the mover 13 is generated to move the mover 13 to the left. Or the magnetic flux is generated so that the direction of the magnetic flux is opposite to that of the mover 13 in the right direction.

Then, by alternating the direction of the current flow to both coils due to the alternating current, the above operation is repeated, and the mover 3 reciprocates with a predetermined stroke in the through direction of the through hole 21 with respect to the yoke 2. Will do.
As described above, in the conventional linear actuator, since the coil is provided not on the mover but on the yoke, it is not necessary to supply power to the mover side, and the moving mover causes a break in the power supply line to the coil. Nothing will happen.

Further, as shown in FIG. 7A, the actuator shaft 11 has a tip shaft portion 13a extending to one end of the yoke 12 supported by a bearing holding portion 29 via a linear motion bearing 28. A positioning sensor 31 is provided on the distal end surface of the holding portion 29 via a lever 30. The positioning sensor 31 is provided with a detected portion 32 provided on the tip shaft portion 13a extending to one end of the movable element 13, and when the movable element 13 moves in the axial direction, the detected portion 32 that moves together with the movable portion 13 is positioned. The movement position of the mover 13 can be detected by detecting the sensor 31.
Further, the tip shaft portion 13b extending to the other end of the yoke 12 is supported by the bearing holding portion 34 via the linear motion bearing 33, whereby the movable element 13 can reciprocate in the axial direction with respect to the stator 12. It is supported by.

By the way, the linear actuator 10 may be incorporated as a head of equipment that requires both rotation and linear motion including an electronic component mounting machine. Such a head can move straight by the linear actuator 10 but cannot rotate by itself. Therefore, the linear actuator 10 is connected as a whole through a power transmission mechanism such as a timing belt. It is comprised so that it may rotate.
However, when the linear actuator 10 is rotated, the originally set position of the positioning sensor 31 is out of order, so that the detected portion 32 provided on the distal end shaft portion 13a of the mover 13 can be detected. Therefore, there is a problem that position detection cannot be performed.

  In addition, in order for the head incorporating the linear actuator 10 to be rotationally driven via a power transmission mechanism such as a timing belt, a housing for housing the entire linear actuator and a pulley for connecting to the timing belt are of course. Since a mechanism for transmitting the rotational force of the pulley to the movable element 13 is required, there is a problem that not only the mechanism becomes complicated, but also the outer shape of the linear actuator becomes large overall. .

  The present invention has been made in consideration of such circumstances, and can have both a linear motion function and a rotation function. In addition, even if the mover reciprocates, the mover can be reliably secured by a positioning sensor. An object of the present invention is to provide a linear actuator that can be detected and that can be prevented from becoming large in size with a simple configuration.

In order to achieve the above object, the present invention proposes the following means.
The invention according to claim 1 is a linear actuator comprising a stator, a mover provided so as to be capable of reciprocating in the axial direction with respect to the stator, and a positioning sensor for detecting a position of reciprocation of the mover. The movable element includes a rotation unit that is rotatably connected coaxially with the movable element.

  According to the first aspect of the invention, when the rotary unit rotates, the mover and the positioning sensor do not rotate at all, so that the positioning sensor can always detect the detected portion, and as a result, the position of the mover Can be reliably detected, and the control of the mover can be performed satisfactorily.

According to a second aspect of the present invention, in the linear actuator according to the first aspect, the rotary unit is connected to a rotary shaft connected to the mover via a bearing, and connected to the rotary shaft via a linear motion bearing. And a motor rotor.
According to the second aspect of the present invention, when the motor rotor rotates, the rotating shaft rotates. However, the rotating shaft of the rotating unit rotates with respect to the mover, so the mover does not rotate.

  According to a third aspect of the present invention, in the linear actuator according to the first or second aspect of the present invention, the linear actuator is connected to the mover, and has a coupling fitting on which a detected portion detected by a positioning sensor is mounted.

  According to the invention of claim 3, when the mover moves, the detected part of the positioning sensor moves together with the movement of the mover by the connecting metal fitting, so that the positioning sensor can detect the detected part reliably. Good detection can be performed.

According to a fourth aspect of the present invention, in the linear actuator according to the third aspect, the detected portion is slidable on a guide rail provided outside the stator.
According to the fourth aspect of the present invention, when the detected part moves together with the mover, it moves smoothly by being guided by the guide rail, so that the positioning sensor can accurately detect the detected part.

  The invention according to claim 5 comprises a stator, a mover provided so as to be capable of reciprocating in the axial direction with respect to the stator, and a positioning sensor for detecting a position of reciprocation of the mover, The detected portion of the positioning sensor is a linear actuator that can reciprocate with the mover outside the stator when the mover reciprocates, and the mover is axially moved with respect to the stator. And a linear motion rotation unit that is slidable and rotatably supported about an axis.

  According to the fifth aspect of the invention, since the mover is provided with bearing means that is movable in the axial direction within the stator and is rotatable around the axis, the detected portion does not rotate at all. The detected portion that moves together with the mover is detected by the positioning sensor outside the stator, and the movement of the mover can be accurately detected.

According to a sixth aspect of the present invention, in the linear actuator according to the fifth aspect, the detected portion of the positioning sensor is attached to a coupling fitting connected to the movable element via a bearing, and is external to the stator. It is slidable on a guide rail provided in the housing.
According to the invention of claim 6, when the mover moves, the detected part of the positioning sensor moves together with the movement of the mover by the connecting bracket, and the positioning sensor can reliably detect the detected part, Good detection can be performed.

According to a seventh aspect of the present invention, in the linear actuator according to the fifth or sixth aspect, the linear motion rotating unit supports the movable element so as to be movable in the axial direction with respect to the stator and to be rotatable about the axis. It is characterized by comprising a bearing means and a motor rotor connected to one end of the mover via a linear motion bearing.
According to the seventh aspect of the present invention, when the motor rotor is driven, the mover can be rotated about the entire axis, so that both linear motion and rotation are performed with respect to the mover of the linear actuator. Can be granted.

  According to the linear actuator of the present invention, since both the linear motion function and the rotation function are provided, the position of the mover can be reliably detected by the positioning sensor even if the mover rotates and reciprocates. In addition, it is possible to avoid an increase in size with a simple configuration.

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing a linear actuator according to a first embodiment of the present invention. FIG. 1 is a front view showing the linear actuator, and FIG. 2 is a plan view of FIG.
As shown in FIG. 1, the linear actuator 10 of this embodiment includes a yoke 12, a mover 13, a pair of permanent magnets 16 and 17, two coils (not shown), and a response of the mover 13. The actuator unit 11 includes a positioning sensor 31 that detects a position. Further, tip shaft portions 13 a and 13 b at both ends of the mover 13 are supported by bearing holding portions 29 and 34 via linear motion bearings 28 and 33.

  Although not shown in detail, the yoke 12 has a rectangular tube shape as a whole by forming a through hole 21 at the center position thereof, and forms a base member by punching a thin steel plate with a press. A plurality of base members are laminated in the penetration direction of the through-hole 21 and are made of laminated steel plates joined while being laminated while adjusting their positions.

  The outer diameter of the mover 13 is slightly smaller than the inner diameter of permanent magnets 14 to 17 described later. The movable element 13 is provided on the inner diameter side of the permanent magnets 14 to 17 so as to be reciprocally movable in the through direction of the through hole 21 with respect to the yoke 12 by being inserted so as to be coaxial with the permanent magnets 14 to 17. . The mover 13 is made of a laminated steel plate in which a thin steel plate is punched out by a press to form an annular base member, and a plurality of the base members are laminated while being aligned. Thereby, the whole needle | mover 13 consists of an iron member.

  The permanent magnets 14 and 15 are made of ferrite magnets having the same diameter, the same length, and the same width, which are formed by cutting a cylinder in parallel at two places at predetermined intervals. The cylinders are aligned and positioned adjacent to each other in the axial direction, and are bonded and fixed to one cylindrical surface portion 22. These permanent magnets 14 and 15 are of radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of the magnetic poles is reversed.

  The permanent magnets 16 and 17 are made of ferrite magnets having the same diameter, the same length, and the same width, which are formed by cutting the inner peripheral surface of the cylinder at two positions in parallel with the axis thereof, and are coaxial with each other. They are arranged with their circumferential positions aligned and adjacent to each other in the axial direction, spaced apart on the opposite side in the circumferential direction so as to face the permanent magnets 14 and 15, and aligned and fixed in the axial direction of the through holes 21. Has been. These permanent magnets 16 and 17 are of radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of the magnetic poles is reversed.

In this embodiment, a rotary unit 40 is connected to the mover 13 so as to be rotatable about an axis coaxially with the mover.
As shown in FIG. 1, the rotating unit 40 includes a rotating shaft 42 and a motor 60, and the rotating shaft 42 is an end portion of the mover 13 of the linear actuator 10 via a ball bearing (bearing) 41. 13b.

The rotary shaft 42 is provided with a ball bearing (bearing) in which a bearing holding portion 43 having an inverted U shape in cross section is provided to extend toward the distal end shaft portion 13 b of the mover 13 and held in the bearing holding portion 43. ) The distal end shaft portion 13b of the mover 13 is press-fitted into the inner ring 41 and is connected to the same axis as the mover 13.
The motor rotor 45 has a hollow central portion in the axial direction, and a linear motion bearing 44 is fitted into the hollow portion, and a rotary shaft 42 is inserted into an inner ring of the linear motion bearing 44.
The motor rotor 45, the linear motion bearing 44, and the rotary shaft 42 are fixed to each other in the rotational direction. When the motor 60 is turned on, the linear motion bearing 44 and the rotary shaft 42 are used for the motor. It rotates with the rotor 45. The rotary shaft 42 is slidable in the axial direction with respect to the linear motion bearing 44.

Therefore, the rotary unit 40 is connected to the mover 13 so as to be rotatable about the same axis as the rotary unit 42, and supports the rotary shaft 42 so as to be slidable in the axial direction. And a rotor 45 for the motor that rotates at a high speed.
In addition, as the linear motion bearings 28 and 33, the linear motion bearing 44 is constituted by, for example, a ball spline type.

  Since the linear actuator of this embodiment is configured as described above, an AC current (sine wave current, rectangular wave current) is applied to a coil (not shown) to generate a magnetomotive force in the yoke 12, and By generating a magnetic flux in a direction based on the direction of the magnetomotive force, the mover 13 moves along the axial direction through the through hole in the yoke 12, for example, in the right direction, and the alternating current is applied to the yoke 12. Is generated in the opposite direction to the magnetomotive force, and a magnetic flux is generated in the direction opposite to the direction of the magnetic flux based on the direction of the magnetomotive force. Moves in the opposite direction (left direction) along the axial direction.

At the time of the movement, the direction of the current flow to the two coils is alternately changed by the alternating current, whereby the mover 3 reciprocates with a predetermined stroke in the through direction of the through hole with respect to the yoke 2.
At this time, the tip shaft portion 13b of the mover 13 is connected to the rotation shaft 42 via the ball bearing 41, and the rotation shaft 42 is supported by the linear motion bearing 44. Therefore, the tip 13b rotates as the mover 13 moves. The shaft 42 moves in the same manner.
Further, when the mover 13 is moved, if the detected portion 32 provided on the distal end shaft portion 13a is also moved accordingly, the position is detected by the positioning sensor 11, so that the position of the mover 13 is accurately grasped. Thus, the movable element 13 can be controlled well.

On the other hand, when the motor 60 is driven and the motor rotor 45 is rotated, the rotational force is transmitted to the rotating shaft 42 via the linear motion bearing 44, so that the rotating shaft 42 rotates.
However, since the movable element 13 of the rotation unit 40 is coaxially connected to one end of the rotation shaft 42 via the ball bearing 41 as described above, even if the rotation shaft 42 rotates, the mover 13 is rotated. Does not rotate.

Therefore, according to this embodiment, when the motor 60 is driven, the linear motion bearing 44 and the rotary shaft 42 rotate together with the motor rotor 45, and the rotary shaft 42 slides in the axial direction with respect to the linear motion bearing 44. It is possible to move.
For this reason, when the rotary shaft 42 rotates, the movable element 13 and the positioning sensor 31 do not rotate at all, so that the positioning sensor 31 can always detect the detected portion 32, so that the position of the movable element 13 is ensured. Therefore, the movable element 13 can be favorably controlled.

  Further, in the rotating unit 40, the rotating shaft 42 is inserted into the motor rotor 45, and the rotating shaft 42 and the mover 13 are concentrically connected via the ball bearing 41, so that a power transmission mechanism such as a timing belt is provided. Compared to the prior art used, the structure is simpler, the increase in the outer diameter of the linear actuator can be avoided, the configuration can be simplified, and the increase in size can be suppressed.

  When this linear actuator 10 is used in a head mounted on a component mounting machine, the rotary shaft 42 on the same axis as the mover 13 is directly rotated by the motor rotor 45. Compared with the prior art using a power transmission mechanism, there is no loss of power transmission, the tact time can be increased, and a component mounting machine with excellent responsiveness can be realized.

3 and 4 show an actuator according to a second embodiment of the present invention.
In this case, the rotating shaft 42 of the rotating unit 40 is connected to the mover 13 of the actuator unit 11 as in the first embodiment.
This embodiment is different from the first embodiment in that the position of the positioning sensor 31 is changed.

That is, the positioning sensor 31 is fixed to the outside of the yoke 12 of the actuator unit 11 as shown in FIG.
On the other hand, the detected portion 32 detected by the positioning sensor 31 is attached to a connection fitting 47 provided on the distal end shaft portion 13 a of the movable element 13. As shown in FIG. 3, the connecting metal fitting 47 has an L shape, and the tip of the short part 47 a is connected to the tip part shaft part 13 a of the movable element 13, and on the tip side of the long part 47 b. The detected portion 32 is attached by a bolt or the like, so that the positional relationship corresponding to the positioning sensor 31 is provided. Although not shown in detail, the positioning sensor 31 is attached to the actuator unit 11 via an L-shaped bracket 46 as shown in FIG. One end of the bracket 46 is attached to the outside of the actuator portion 11, and the positioning sensor 31 is attached on the sliding locus of the detected portion 32 at the other end.

And when the needle | mover 13a reciprocates, the to-be-detected part 32 moves with it, and the movement can be detected by the positioning sensor 31 now.
Further, the detected part 32 is guided by a guide rail 48 laid outside the stator 12. The guide rail 48 is laid along the moving direction of the mover 13 outside the stator 12, and the detected portion 32 is slidable thereon.
3 and 4, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  Therefore, according to this embodiment, since the rotation unit 40 is provided, it is the same as that of the first embodiment except that the positioning sensor 31 is fixed to the outside of the actuator unit 11. In addition, the detected portion 13 of the positioning sensor 31 is provided outside the stator 12 so as to be able to reciprocate similarly to the mover 13 by the guide rail 48, so that the length of the mover 13 is longer than that of the first embodiment. Therefore, the entire linear actuator can be reduced in size.

5 and 6 show a linear actuator according to a third embodiment of the present invention.
In this case, the tip shaft portion 13b of the movable element 13 of the linear actuator unit 11 is connected to the motor rotor 45 via the linear motion bearing 44, and the movable element 13 includes a linearly movable and rotatable bearing means 49. And are supported by bearing holding portions 29 and 34. The bearing means 49 supports the mover 13 so as to be movable in the axial direction thereof and to be rotatable about the axial line, and constitutes a so-called linear / rotary bearing.

  A short part 47 a of the connecting metal fitting 47 is connected to the tip shaft part 13 a of the movable element 13 through a ball bearing (bearing) 51. In the connection fitting 47, the detected portion 32 of the positioning sensor 31 is attached to the distal end side of the long portion 47 b, and the detected portion 32 slides on the guide rail 48.

That is, in this embodiment, the bearing means 49 that supports the movable element 13 so as to be movable in the axial direction with respect to the stator 12 and rotatable about the axis line, and the linear motion bearing 44 on the distal end shaft portion 13 b of the movable element 13. And the motor rotor 45 connected via the rotary linear motion unit 50.
5 and 6, the same parts as those in FIGS. 1 to 4 are denoted by the same reference numerals.

  In this embodiment, when the movable element 13 moves in the axial direction by driving the linear actuator unit 11, the movable element 13 can reciprocate in the axial direction with respect to the through hole 21 in the stator 12 and can rotate about the axis. Since the positioning means 31 is provided, the positioning sensor 31 itself does not rotate at all, so that the detected part 32 that moves together with the movable element 13 is detected by the positioning sensor 31 outside the stator 12, The movement of the mover 13 can be accurately detected, and therefore the position cannot be detected.

Moreover, the rotary linear motion unit 50 includes the bearing means 49 and the motor rotor 45 described above, and when the motor rotor 45 is driven, the mover 13 can be rotated about the entire axis. Therefore, both the linear motion function and the rotation function can be imparted to the mover 13 of the linear actuator 10.
As a result, similarly to the second embodiment, the length of the movable element 13 can be shortened, and compared to the first embodiment, it is not necessary to provide the rotating shaft 42 and the bearing holding portion 43, and the configuration can be reduced. It can be further simplified.

Then, when the linear actuator 10 of each of the above embodiments is applied to a mounter of a component mounting machine, for example, in a semiconductor manufacturing facility, a small object such as a chip may be moved or rotated in the axial direction. In addition, since positioning during reciprocating operation can be performed accurately, the reliability as a component mounting machine can be increased, which is extremely useful in practice.
Further, in each of the above embodiments, an example in which a rotation unit and a linear motion rotation unit are provided has been described. However, a specific configuration example of each unit is not limited to the illustrated example. What is necessary is just to obtain a function.

It is a front view which shows the linear actuator which concerns on 1st Embodiment of this invention. It is a top view of FIG. It is a front view which shows the linear actuator which concerns on 2nd Embodiment of this invention. FIG. 4 is a plan view of FIG. 3. It is a front view which shows the linear actuator which concerns on 3rd Embodiment of this invention. FIG. 6 is a plan view of FIG. 5. It is a figure which shows the conventional linear actuator, Comprising: (a) is a front view, (b) is a top view of (a).

Explanation of symbols

10 Linear actuator 12 Yoke (stator)
13 Movable element 31 Positioning sensor 32 Detected part 40 Rotating unit 41, 51 Ball bearing (bearing)
42 Bearing holding portion 44 Linear motion bearing 45 Motor rotor 47 Connecting bracket 48 Guide rail 49 Bearing means 50 Linear motion rotating unit

Claims (7)

In a linear actuator comprising a stator, a mover provided so as to be capable of reciprocating in the axial direction with respect to the stator, and a positioning sensor for detecting a position of reciprocation of the mover,
A linear actuator comprising a rotation unit that is connected to the mover so as to be rotatable coaxially with the mover. The linear actuator according to claim 1,
The rotary unit includes a rotary shaft connected to the mover via a bearing, and a motor rotor connected to the rotary shaft via a linear motion bearing. The linear actuator according to claim 1 or 2,
A linear actuator having a coupling fitting coupled to the movable element and mounted with a detected portion detected by a positioning sensor. The linear actuator according to claim 3, wherein
The linear actuator according to claim 1, wherein the detected portion is slidable on a guide rail provided outside the stator. A stator, a mover provided so as to be capable of reciprocating in the axial direction with respect to the stator, and a positioning sensor for detecting a position of the reciprocating movement of the mover; A linear actuator capable of reciprocating with the mover outside the stator during reciprocation of the mover;
A linear actuator comprising: a linear motion rotation unit that supports the mover so as to be slidable in an axial direction and rotatable about an axis with respect to the stator. The linear actuator according to claim 5, wherein
The detected portion of the positioning sensor is mounted on a coupling fitting connected to the mover via a bearing, and is slidable on a guide rail provided outside the stator. Characteristic linear actuator. The linear actuator according to claim 5 or 6,
The linear motion rotation unit is connected to a bearing means for supporting the mover in an axial direction with respect to the stator so as to be rotatable about an axis, and to one end of the mover via a linear motion bearing. A linear actuator comprising a motor rotor.

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