JP2013192354A - Linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a relatively great thrust in slender structure.SOLUTION: A linear actuator comprises a permanent magnet section 20 supported to linearly move by a predetermined amount, a guide tube part 40 comprised of a non-magnetic substance and covering the permanent magnet section 20 for a full length of a moving range in a tubular shape, a first electromagnet section 50 attracting and repulsing the permanent magnet section 20 from one end side in an axial direction, a second electromagnet section 60 attracting and repulsing the permanent magnet section 20 from another end side in the axial direction, and an output section 30 interlocked with the movement of the permanent magnet section 20.

Description

  The present invention relates to a linear actuator that is used in, for example, a zoom lens function of an endoscope, an ablation cutter, and the like and linearly drives a movable part.

In recent years, as a linear actuator for an endoscope in particular, a thinner mechanism has been demanded from the viewpoint of reducing the burden on the patient when inserted into the body.
As this type of prior art, for example, a configuration in which a moving lens for changing the depth of field is moved back and forth using a motor and a ball screw mechanism as described in Patent Document 1 is known. However, in such a configuration, in order to obtain a large driving force with a slimmer device, it is necessary to combine a gear head or the like to increase the motor output, and there is a high possibility that the cost will increase.

Further, as another prior art, as described in Patent Document 2, a first center yoke and a second center yoke provided opposite to each other inside a combination of the first yoke and the second yoke, A first coil wound and fixed on the first center yoke, a second coil wound and fixed on the second center yoke, and a first permanent magnet fixed on the tip of the second center yoke , A second permanent magnet which is displaceable between the first permanent magnet and the first center yoke and is provided so that the same polarity as the first permanent magnet faces magnetically, and one end fixed to the second permanent magnet The other end penetrates through the first center yoke or the second center yoke, and the current flowing through the first coil and the second coil is controlled, so that the second permanent magnet and the second permanent magnet are controlled. Permanent magnet and first sensor The interaction of magnetic force generated between York, there is a solenoid controlled linear actuator and an output shaft for transmitting the displacement and the thrust generated in the second permanent magnet.
However, the latter prior art has a complicated structure such as using a plurality of permanent magnets and having a yoke inside and outside each coil, and is difficult to use in a thin configuration.

JP 2003-98570 A JP 2004-15997 A

  This invention makes it an example of a subject to cope with the said conventional situation. That is, it is an object of the present invention that it is easy to make a slender structure, that a relatively large driving force can be obtained, that the structure is simple and excellent in productivity, and that the cost is low.

  One means for solving the above problems is a permanent magnet part supported so as to move in a straight line by a predetermined amount, and a guide cylinder part made of a non-magnetic material and covering the permanent magnet part in a cylindrical shape over the entire length of the moving range. A first electromagnet part that attracts and repels the permanent magnet part from one end side in the axial direction; a second electromagnet part that attracts and repels the permanent magnet part from the other end side in the axial direction; and And an output unit interlocking with movement.

Since the present invention is configured as described above, the following effects can be obtained.
Since the structure is simple, it is easy to obtain a slim and cost-effective structure. In addition, since the structure uses a plurality of electromagnet portions, a relatively large propulsive force can be obtained.

It is a section perspective view showing an example of the linear actuator concerning the present invention. It is a perspective view which shows an example of the linear actuator which concerns on this invention.

  In order to carry out the present invention, in the first embodiment, a permanent magnet portion supported so as to move linearly by a predetermined amount, and a guide that is made of a non-magnetic material and covers the permanent magnet portion in a cylindrical shape over the entire length of the moving range. A cylindrical portion; a first electromagnet portion that attracts and repels the permanent magnet portion from one end side in the axial direction; a second electromagnet portion that attracts and repels the permanent magnet portion from the other end side in the axial direction; and the permanent magnet And an output unit that interlocks with the movement of the unit.

  In the second embodiment, in order to obtain a particularly large propulsive force, the permanent magnet part is attracted by one of the first electromagnet part and the second electromagnet part, and at the same time the permanent magnet part is repelled by the other. Then, the permanent magnet part and the output part are moved.

  In the third embodiment, as a specific structure for outputting the driving force to the outside, the output portion is formed in a long shaft shape, and the permanent magnet portion is fixed to the center side thereof, and both end sides thereof are Each is inserted through the first electromagnet part and the second electromagnet part, and at least one end side in the axial direction is exposed to the outside.

  In the fourth embodiment, in order to obtain a larger propulsive force, each of the first electromagnet part and the second electromagnet part has a coil part that generates a magnetic field when energized, and a magnet inserted through the coil part. A body core is provided, and the output part is inserted through the magnetic core so as to move linearly.

  In the fifth embodiment, in order to obtain a larger driving force, the magnetic core is fixed to one end side of the cylindrical portion so as to face the cylindrical portion fixed to the coil portion and the permanent magnet portion. The suction repulsion part is formed in an annular shape having an outer diameter larger than that of the cylindrical part.

  In the sixth embodiment, in order to obtain a slender structure with good productivity, a long cylindrical case part is provided, and in the case part, the permanent magnet part, the guide cylinder part, the first electromagnet part, A second electromagnet part and the output part were accommodated.

  In the seventh embodiment, in order to facilitate power supply to the electromagnet portion, the inner surface of the case portion and the first and second inner surfaces of the case portion are arranged between the inner surface of the case portion and the outer surface of the guide tube portion. A gap was provided between the electromagnet portion and the lead wires of the first and second electromagnet portions were inserted into the gap.

  In the eighth embodiment, a sensor unit for detecting the movement of the permanent magnet unit or the output unit is provided so that a signal when the output unit moves can be externally output.

  Hereinafter, a particularly preferred embodiment of the above embodiment will be described in detail with reference to the drawings.

1 and 2 show an example of a linear actuator according to the present invention. FIG. 2 is a perspective view of the linear actuator 1. FIG. 1 is a cross-sectional perspective view seen from the direction indicated by AA ′ in FIG. 2 and shows the internal structure of the linear actuator 1.
The linear actuator 1 includes a permanent magnet portion 20 supported so as to move in a predetermined amount in a linear shape in a long cylindrical case portion 10, and an output portion 30 interlocking with the movement of the permanent magnet portion 20. A guide tube portion 40 made of a non-magnetic material and covering the permanent magnet portion 20 in a cylindrical shape over the entire length of the moving range; a first electromagnet portion 50 that attracts and repels the permanent magnet portion 20 from one end side in the axial direction; The first electromagnet unit 40 and the second electromagnet include a second electromagnet unit 60 that attracts and repels the permanent magnet unit 20 from the other end side in the axial direction, and a sensor unit 70 that detects the movement of the output unit 60. The permanent magnet part 20 is attracted by one of the parts 50 and the permanent magnet part 20 is repelled by the other, and the permanent magnet part 20 and the output part 30 are moved linearly.

The case portion 10 is a long cylindrical member having both ends opened, and has a single or plural (two in the illustrated example) cut-out portion on the peripheral wall on the rear end side (the right end side in the illustrated example). 11 and 12. The notches 11 and 12 are used, for example, to expose a sensor unit 70 and wiring members 71a and 84 which will be described later.
The case portion 10 is formed of a non-magnetic material so as not to magnetically affect the permanent magnet portion 20, the first electromagnet portion 50, and the second electromagnet portion 60. Specific examples of the material of the case portion 10 include SUS303, other nonmagnetic metal materials, synthetic resin materials, ceramics, and the like.

The permanent magnet portion 20 is a cylindrical permanent magnet formed so as to move in the front-rear direction in a guide tube portion 40 to be described later, and the output portion 30 is inserted and fixed at the center thereof.
In the present embodiment, the permanent magnet portion 20 uses a neodymium magnet (for example, N48). However, as another example, a mode using other permanent magnets such as a ferrite magnet and an alnico magnet, It is also possible to adopt an embodiment in which other materials (for example, rubber or the like) are combined.

The output part 30 is formed in a long shaft shape, is inserted into the case part 10 over substantially the entire length of the case part 10, fixes the permanent magnet part 20 to the center side in the axial direction, The first electromagnet part 50 and the second electromagnet part 60 are inserted, and the front end side protrudes forward and is exposed to the outside of the case part 10.
The output unit 30 is made of a nonmagnetic material, specifically, a nonmagnetic metal material (for example, SUS402J2 or the like). However, as another example, the output unit 30 can be made of a synthetic resin material or the like. is there. Furthermore, as another example, the output unit 30 can be formed of a magnetic material.
A movable member (not shown) according to the use of the linear actuator, such as a zoom lens, a cutter, or a mirror, is attached to the front end portion of the output unit 30.

The guide cylinder part 40 is formed in a cylindrical shape having a length that covers at least the moving range of the permanent magnet part 20. The guide cylinder portion 40 is formed to have an inner diameter slightly larger than the outer diameter of the permanent magnet portion 20 so as to accommodate the permanent magnet portion 20 so as to be linearly movable in the front-rear direction. The guide tube portion 40 is formed of a nonmagnetic material so as to prevent the permanent magnet portion 20 from being magnetically affected from the radially outer side. In this embodiment, the guide tube portion 40 is made of a nonmagnetic metal material (for example, SUS303). ) Is used. As another example of the material of the guide tube portion 40, a synthetic resin material, ceramic, or the like can be used.
And the guide cylinder part 40 of the said structure is hold | maintained so that it may be eccentric with respect to the center of the case part 10 by being supported by the magnetic body core before and behind mentioned later. Accordingly, a gap s <b> 1 is formed between the outer peripheral surface of the guide tube portion 40 and the inner peripheral surface of the case portion 10. The gap s1 is used to insert a lead wire 51a of the first electromagnet unit 50 described later.

  The first electromagnet part 50 includes a coil part 51 that is disposed on an extension line of the central axis of the permanent magnet part 20 and generates a magnetic field when energized, and a magnetic core 52 that is inserted through the coil part 51. The output portion 30 is inserted through the magnetic core 52 so as to move linearly.

The coil portion 51 is formed by winding an insulated conductive wire in a coil shape, and has a power supply lead wire 51a on the outer peripheral side thereof.
The coil portion 51 is supported so as to be eccentric with respect to the center of the case portion 10 in the same manner as the guide tube portion 40 by being supported on the outer periphery of a magnetic core 52 described later. Therefore, a gap s2 communicating with the gap s1 is formed between the outer peripheral surface of the coil portion 51 and the inner peripheral surface of the case portion 10. The gap s2 is used to guide the lead wire 51a backward. (Refer to the enlarged view of part B in Fig. 1)

The magnetic core 52 is integrally formed from a cylindrical portion 52a inserted into the coil portion 51 and a suction repulsion portion 52b fixed to the rear end side of the cylindrical portion 52a so as to face the front end portion of the permanent magnet portion 20. Configured.
The cylindrical portion 52a and the suction repulsion portion 52b are formed of a magnetic metal material such as iron so as to enhance the magnetic force generated by the coil portion 51. In this embodiment, carbon tool steel (for example, SK4) is used. .

The cylindrical portion 52 a has an inner diameter slightly larger than the outer diameter of the output portion 30 so as to be slidably inserted through the output portion 30 and protrude from the front and rear end portions of the coil portion 51, and from the coil portion 51. Is also formed in a long cylindrical shape that is long in the axial direction.
A portion of the cylindrical portion 52 a that is in front of the coil portion 51 (left side according to FIG. 1) is fixed to the case portion 10 via a spacer 81. The spacer 81 is a substantially cylindrical member fitted to the front end side of the inner peripheral surface of the case portion 10, and the front end portion of the cylindrical portion 52 a is inserted and fixed at a position eccentric from the center portion. The spacer 81 is made of a nonmagnetic material such as a synthetic resin material (for example, PEEK: polyetherketone).
Further, a suction repulsion portion 52b is annularly attached and fixed to a portion of the cylindrical portion 52a on the rear side (right side according to FIG. 1) from the coil portion 51.

The suction repulsion part 52b is formed in an annular shape having an outer diameter larger than that of the cylinder part 52a, and is inserted into and fitted to the inner peripheral surface on the front end side of the guide cylinder part 40, so that the guide cylinder part 40 moves at an eccentric position. It is fixed impossible.
In addition, according to the example of illustration, although the magnetic body core 52 was comprised combining the cylindrical part 52a and the attraction | suction repulsion part 52b of another body, as another example of this magnetic body core 52, the magnetic material of one member is processed. It may be what you did.

The second electromagnet part 60 is arranged symmetrically with the first electromagnet part 50 so as to sandwich the permanent magnet part 20, and substantially the same as the first electromagnet part 50, the coil part 61, the lead wire 61 a, and the like. And a magnetic core 62 comprising a cylindrical portion 62a and a suction repulsion portion 62b.
The second electromagnet part 60 is located on an extension line of the center line of the permanent magnet part 20 and is arranged eccentrically with respect to the case part 10 so that the outer peripheral surface of the coil part 61 and the inner peripheral surface of the case part 10 A gap s3 is formed through which the lead wires 51a and 61a of the coil portions 51 and 61 are inserted. (See the enlarged view of part C in Fig. 1)

  The portion on the rear side (right side according to FIG. 1) of the cylindrical portion 62 a of the magnetic core 62 is fixed to the case portion 10 via the spacer 82. The spacer 82 is a substantially cylindrical member fitted to the front end side of the inner peripheral surface of the case portion 10, and the rear end portion of the cylindrical portion 62a is inserted and fixed at a position eccentric from the center thereof. The spacer 82 is made of a nonmagnetic material such as a synthetic resin material (for example, PEEK: polyetherketone). And the outer peripheral part of this spacer 82 is notched partially, The clearance | interval s4 which allows the lead wires 51a and 61a to be inserted between the inner peripheral surfaces of the case part 10 is ensured.

Further, a suction repulsion portion 62b is annularly attached and fixed to a portion of the cylindrical portion 62a of the magnetic core 62 that is in front of the coil portion 51 (left side according to FIG. 1). The suction repelling part 62b is inserted and fitted into the inner peripheral surface on the rear end side of the guide cylinder part 40, thereby fixing the guide cylinder part 40 so as not to move at an eccentric position.
And the dimension of the front-back direction between the attraction repulsion part 62b of the 2nd electromagnet part 60 and the above-mentioned attraction repulsion part 52b of the 1st electromagnet part 50 is the movement space of the permanent magnet part 20 between these. It is set appropriately to ensure.

The sensor unit 70 includes a detection unit 71 that is fixedly fixed to the case unit 10 via a support member 83, and a cover that is fixed to the outer peripheral part of the output unit 30 so as to advance and retreat integrally with the output unit 30. It comprises a detection unit 72.
The sensor unit 70 is a Hall sensor that detects a magnetic field using the Hall effect, and outputs the detection signal via a wiring member 71a (for example, a flexible printed circuit board).

  The detected portion 72 is a permanent magnet whose position can be detected by the detecting portion 71. According to the illustrated example, the detected portion 72 has an annular shape on the outer periphery of the output portion 30 so as to move in the front-rear direction between the spacer 82 and the support member 83. It is fixed.

The support member 83 is a member fitted and fixed to the inner surface on the rear end side of the case portion 10. The output unit 30 is inserted into the support member 83 so as to freely advance and retract. The support member 83 is made of a nonmagnetic material such as a synthetic resin material (for example, PEEK: polyetherketone).
In addition, the detection unit 71 and the wiring member 71a are supported outside the support member 83 so as to be exposed from one cutout portion 11 of the case portion 10, and further from the other cutout portion 12 of the case portion 10. The wiring member 84 is supported so as to be exposed. The wiring member 84 is made of, for example, a flexible printed circuit board, and guides the lead wires 51a and 61a of the first and second electromagnet portions 50 and 60 to the outside.

Next, the characteristic operation and effect of the linear actuator having the above configuration will be described.
For example, when the output unit 30 is moved forward from the position shown in FIG. 1, the permanent magnet unit 20 is attracted by the first electromagnet unit 50 and simultaneously repelled by the second electromagnet unit 60. As described above, DC power is supplied to the first electromagnet unit 50 and the second electromagnet unit 60.
Then, the permanent magnet unit 20 and the output unit 30 move forward by receiving both the attractive force of the first electromagnet unit 50 and the repulsive force of the second electromagnet unit 60, and the front end of the permanent magnet unit 20 is magnetized. It stops at the forward movement position that is in contact with the rear end of the body core 52.
Moreover, if the positive / negative of direct-current power supplied to the 1st electromagnet part 50 and the 2nd electromagnet part 60 is switched from this state, the permanent magnet part 20 and the output part 30 will be the repulsive force of the 1st electromagnet part 50. And the second electromagnet part 60 are moved backward by the attractive force of the second electromagnet part 60 and stopped at the retracted position where the rear end of the permanent magnet part 20 is brought into contact with the front end of the magnetic core 62.
Whether the output unit 30 is in the forward position or the backward position is detected by the sensor unit 70, and the detection signal is externally output via the wiring member 71a.

  Moreover, if the electric power supplied to the 1st electromagnet part 50 and the 2nd electromagnet part 60 is adjusted suitably, the permanent magnet part 20 and the output part 30 will be in the middle position between the advance position and the retreat position. It is also possible to hold it.

Therefore, according to the linear actuator 1 of the present embodiment, a relatively large propulsive force can be obtained by the repulsive force and the attractive force of the two electromagnets, and the propulsion direction can be changed, or the output unit 30 can be placed at an intermediate position. Further, the position of the output unit 30 can be detected by the sensor unit 70.
Further, the lead wire 51a is formed by gaps s1, s2, s3, and s4 formed between the inner peripheral surface of the case portion 10 and the first electromagnet portion 50, the guide tube portion 40, the second electromagnet portion 60, and the spacer 82. 61a is guided rearward, so that it is not necessary to provide a protruding portion on the outer periphery of the case portion 10, so that the linear actuator 1 can be effectively used as a thin actuator such as an endoscope. .

In addition, according to the said Example, although comprised so that the position of the output part 30 might be detected by the sensor part 70, as a structure, it may be set as the structure which detects the position of the permanent magnet part 20 by the sensor part 70 as another example. Is possible.
Further, according to the above embodiment, a Hall sensor is used as the sensor unit 70. However, as another example of the sensor unit 70, a contact sensor (for example, a limit sensor) that senses the position of the permanent magnet unit 20 or the output unit 30 is used. Switch) and other non-contact sensors (for example, proximity switches).

  Moreover, in the said Example, although the case part 10 was comprised with the nonmagnetic body so that the permanent magnet part 20 might not receive the magnetic influence from a radial direction, the material and thickness of the guide cylinder part 40 which are nonmagnetic bodies In the case where it is possible to reduce the magnetic influence that the permanent magnet portion 20 receives from the radially outward direction by adjusting the above, the case portion 10 can be made of a magnetic material.

  In the above-described embodiment, as a particularly preferable control method, the permanent magnet unit 20 is attracted by one of the first electromagnet unit 50 and the second electromagnet unit 60, and at the same time the permanent magnet unit 20 is repelled by the other. Then, the permanent magnet unit 20 and the output unit 30 are moved. As another example, the permanent magnet unit 20 and the output unit 30 are made permanent by the attractive force or the repulsive force of either the first electromagnet unit 50 or the second electromagnet unit 60. It is also possible to move the magnet unit 20 and the output unit 30.

  Further, in the above embodiment, the spacer 81 and the spacer 82 having different shapes are used on the front end side and the rear end side in the case portion 10. However, as another example, the same spacers 82 and 82 are used for both, and the front end side is used. By closing the gap between the spacer 82 and the case portion 10 with another member such as an adhesive, the two spacers can be made into a common part.

  Moreover, according to the said Example, although it was set as the structure which protrudes the front-end side of the output part 30 to the front of the case part 10, as another example, the rear-end side of the output part 30 protrudes to the back of the case part 10. The aspect which made it a structure, the case part 10 and the guide cylinder part 40 are provided with the long hole of the front-back direction penetrated to radial direction, and the output part (not shown) provided out of the case part 10 through this long hole ) May be connected to the permanent magnet unit 20.

  Moreover, according to the example of illustration, although the output part 30 becomes a structure which can rotate centering on the axis line, it is also possible to set it as the structure which the output part 30 cannot rotate. This configuration includes, for example, the output unit 30 or the permanent magnet unit 20 and a non-rotatable member around the output unit 30 or the permanent magnet unit 20 (specifically, the magnetic cores 52 and 62, the guide tube unit 40 or the support). One of the members 83) is provided with a groove in the front-rear direction, and the other is provided with a convex portion that is immovable in the circumferential direction with respect to the groove and fits so as to be movable in the front-rear direction. .

DESCRIPTION OF SYMBOLS 1: Linear actuator 10: Case part 20: Permanent magnet part 30: Output part 40: Guide cylinder part 50: 1st electromagnet part 60: 2nd electromagnet part 51, 61: Coil part 52, 62: Magnetic body core 51a , 61a: Lead wires 52a, 62a: Tube portions 52b, 62b: Suction repulsion portions 70: Sensor portions s1, s2, s3, s4: gaps

Claims (8)

  A permanent magnet portion that is supported so as to move linearly by a predetermined amount, a guide cylinder portion that is made of a non-magnetic material and covers the permanent magnet portion in a cylindrical shape over the entire length of the movement range, and one end in the axial direction of the permanent magnet portion A first electromagnet part that attracts and repels from the side, a second electromagnet part that attracts and repels the permanent magnet part from the other end side in the axial direction, and an output unit that interlocks with the movement of the permanent magnet part A linear actuator characterized by   Of the first electromagnet part and the second electromagnet part, the permanent magnet part is attracted by one of the first electromagnet part and the permanent magnet part is repelled by the other to move the permanent magnet part and the output part. The linear actuator according to claim 1, which is configured as described above.   The output portion is formed in a long shaft shape, and the permanent magnet portion is fixed to the center side of the output portion, and both end sides thereof are inserted into the first electromagnet portion and the second electromagnet portion, respectively. The linear actuator according to claim 1, wherein at least one end side in the direction is exposed to the outside.   Each of the first electromagnet part and the second electromagnet part includes a coil part that generates a magnetic field when energized, and a magnetic core inserted through the coil part. The linear actuator according to claim 3, wherein the output unit is inserted so as to move linearly.   The magnetic core has a cylindrical portion fixed in the coil portion, and a suction repulsion portion fixed to one end side of the cylindrical portion so as to face the permanent magnet portion. The linear actuator according to claim 4, wherein the linear actuator is formed in an annular shape having an outer diameter larger than that of the cylindrical portion.   A long cylindrical case part is provided, and the permanent magnet part, the guide cylinder part, the first electromagnet part, the second electromagnet part, and the output part are housed in the case part. The linear actuator according to any one of claims 1 to 5.   A gap is provided between the inner surface of the case portion and the outer surface of the guide tube portion, and between the inner surface of the case portion and the first electromagnet portion and the second electromagnet portion, and the first electromagnet portion is formed in the gap. The linear actuator according to claim 6, wherein lead wires of the electromagnet part and the second electromagnet part are inserted.   The linear actuator according to any one of claims 1 to 7, further comprising a sensor unit that detects movement of the permanent magnet unit or the output unit.

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