JP2008048556A - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear actuator of a simple configuration for achieving a smaller size. <P>SOLUTION: A linear actuator 1 comprises first and second yokes 6 and 7 facing each other, a magnet array 9 fixed on the first yoke 6, air core coils 8A and 8B that are set movably in a lengthwise direction to face the magnet array 9, and a holder 10 which holds the air core coils 8A and 8B. The holder 10 comprises a pair of first projections 12a and 12b and a pair of second projections 13a and 13b protruding from a body 11 toward the first yoke 6 and the second yoke 7, respectively. The first projections 12a and 12b are dropped into a guide slot 15, and guided in the lengthwise direction of the guide slot 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a small moving coil type linear actuator used for driving an optical disk device.

Conventionally, there is JP-A-5-146135 as a technique in such a field. In the linear actuator described in this publication, the movable coil is sandwiched between upper and lower magnet arrays, and the movable element having the movable coil is connected to two guide rails installed on the left and right sides via a slider. The mover moves smoothly while being guided by the two guide rails.
JP-A-5-146135 JP 2002-95231 A Japanese Utility Model Publication No. 60-51782

  However, in the linear actuator described in the above document, in order to move the mover smoothly, two guide rails are provided on both the left and right sides of the mover, so there is a space for the two guide rails. It was difficult to further reduce the size of the linear actuator.

  An object of the present invention is to provide a linear actuator that has a simple configuration and facilitates further miniaturization.

  The linear actuator according to the present invention is formed in a long shape, and is between the first magnetic body and the second magnetic body, and the first magnetic body and the second magnetic body facing each other in the thickness direction. A plurality of magnets which are arranged and fixed to at least one of the first magnetic body and the second magnetic body and arranged in parallel so that the polarities are alternately changed in the longitudinal direction; the first magnetic body and the second magnetic body; An air-core coil that is opposed to the magnet and is movable in the longitudinal direction, a main body that holds the air-core coil, and the first magnetic body and the second magnetic body. And a holder having a first protrusion and a second protrusion protruding from the main body.

  In the linear actuator according to the present invention, the holder disposed between the first magnetic body and the second magnetic body facing each other is supported by the first protrusion and the second protrusion of the holder while being long. Can move in the direction. As a result, the play of the holder can be prevented in the thickness direction between the first magnetic body and the second magnetic body, and accordingly, two parallel guide rails are required. Therefore, the linear actuator can be easily downsized with a simple configuration.

  In the linear actuator according to the present invention, it is preferable that the first protrusion and the second protrusion are in sliding contact with the surfaces of the first magnetic body and the second magnetic body, respectively, apart from the magnet. is there.

  Since it is sufficient to secure a space between the first magnetic body and the second magnetic body in consideration of the thickness of the magnet and the thickness of the holder (or air core coil), it is possible to promote the thinning of the linear actuator. Can do. Furthermore, since the protrusion does not contact the magnet, the holder can be moved smoothly.

  According to the present invention, it is possible to provide a linear actuator that has a simple configuration and facilitates further miniaturization.

  Hereinafter, preferred embodiments of a linear actuator according to the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 4, the linear actuator 1 is a two-phase moving coil type linear actuator, and includes a long case 2 having an opening H extending in the longitudinal direction and the opening H. And a guide rail 5 extending in the longitudinal direction, brackets 3 and 4 for fixing both ends of the guide rail 5 to the case 2, and a holder 10 that slides along the guide rail 5.

  The case 2 includes a first yoke (first magnetic body) 6 disposed on the bottom and a second yoke (second magnetic body) 7 disposed on the top of the first yoke 6. The first yoke 6 is formed by bending a single flat plate into an L shape, and includes a base portion 6a that forms the bottom surface of the case 2, and a wall portion 6b that is erected on the base portion 6a. (See FIG. 3). In addition, brackets 3 and 4 are provided at both ends of the base portion 6 a of the first yoke 6 so as to protrude from the base portion 6 a toward the installation direction of the guide rail 5. On the other hand, the second yoke 7 is a so-called hat-shaped member formed by bending a single flat plate. The second yoke 7 includes a top plate portion 7c facing the base portion 6a and the top plate. It is comprised from a pair of flange parts 7a and 7b provided in the both ends of the part 7c.

  The first yoke 6 and the second yoke 7 are formed in a long shape with a magnetic material and are installed so as to face each other in the thickness direction. The flange portions 7a and 7b of the second yoke 7 are fixed to both ends of the base portion 6a on the first yoke 6 side by screws B1 and B2, and the first yoke 6 and the second yoke 7 are fastened. Thus, the case 2 is formed.

  Inside the case 2, a magnet row 9 is fixed on the base portion 6 a of the first yoke 6. The magnet row 9 extends in the longitudinal direction of the first yoke 6 and is configured by being arranged in parallel so that the north pole of the magnet 9a and the south pole of the magnet 9b appear alternately. Further, a gap is formed between the magnet array 9 and the second yoke 7 as a gap that allows the holder 10 to slide at a constant interval.

  As shown in FIGS. 5 and 6, the holder 10 made of resin includes a rectangular main body 11 and a slider 14 that connects the main body 11 and the guide rail 5.

  The main body portion 11 is provided with two rectangular coil housing portions 11a and 11b for juxtaposing the two air-core coils 8A and 8B. As shown in FIG. 2, the coil housing portions 11a and 11b have a step 11c in the thickness direction of the main body 11, and the air-core coils 8A and 8B are fitted into the coil housing portions 11a and 11b, and the step 11c. And is fixed to the main body 11 with an adhesive.

  The air-core coils 8A and 8B are juxtaposed in the longitudinal direction of the magnet array 9, and the distance between the center position of the air-core coil 8A and the center position of the air-core coil 8B is π more than the parallel arrangement period 2π of the magnets 9a and 9b. / 2 is arranged to be shorter. Thereby, the linear actuator 1 can operate as a two-phase linear stepping motor.

  In addition, each air-core coil 8A, 8B winds the self-bonding enamel wire flatly so that a substantially rectangular gap K is formed in the center, and the self-bonding enamel wire adheres by applying heat. It is formed. The air-core coils 8A and 8B have a pair of long side portions 8a and a pair of short side portions 8b that face each other with the gap portion K interposed therebetween.

  Further, the holder 10 includes first protrusions 12 a and 12 b and a second protrusion 13 a that protrude from the main body 11 toward the first yoke 6 and the second yoke 7 in the thickness direction of the main body 11. , 13b are integrally formed. The first protrusions 12a and 12b projecting toward the first yoke 6 are substantially rectangular parallelepiped, and are disposed at the corners farther from the slider part 14 among the four corners of the rectangular main body 11. . The first protrusions 12a and 12b are formed to be elongated so as to extend in the longitudinal direction. On the other hand, the second projecting portions 13a and 13b projecting toward the second yoke 7 are formed in a columnar shape, and are integrated with the main body 11 at a position facing the first projecting portions 12a and 12b. Is formed.

  The slider portion 14 protruding from the opening H of the case 2 is a member that connects the main body portion 11 and the guide rail 5, and a through-hole 14 a extending along the longitudinal direction of the slider portion 14 is formed therein. Is formed. Then, the guide rail 5 is inserted into the through hole 14 a of the slider 14, whereby the holder 10 is guided by the guide rail 5.

  As shown in FIGS. 3 and 4, the magnet row 9 fixed on the base portion 6 a of the first yoke 6 and the wall portion 6 b of the first yoke 6 are separated by a certain distance. A guide groove 15 extending in parallel with the guide rail 5 is formed in the case 2 using a space that appears as a result of the separation. The first protrusions 12a and 12b of the holder 10 are dropped into the guide groove 15 and slide. By the cooperation of the first protrusions 12a and 12b and the guide groove 15 and the cooperation of the guide rail 5 and the through hole 14a of the slider part 14, the play in the width direction when the holder 10 is moved is prevented. Is reliably guided in the longitudinal direction. The first protrusions 12a and 12b and the guide groove 15 can be used as auxiliary guides.

  In the thickness direction of the linear actuator 1, the first protrusions 12 a and 12 b are separated from the magnet row 9 and are in sliding contact with the surface of the first yoke 6 along the longitudinal direction of the guide groove 15. The second protrusions 13 a and 13 b are separated from the magnet row 9 and are in sliding contact with the surface of the second yoke 7.

  With such a configuration, the holder 10 disposed between the first yoke 6 and the second yoke 7 facing each other is guided to the guide rail 5 via the slider portion 14 on the side adjacent to the guide rail 5, The linear actuator 1 can move in the longitudinal direction while being supported by the first protrusions 12 a and 12 b and the second protrusions 13 a and 13 b on the side opposite to the guide rail 5. In the thickness direction of the linear actuator 1, the first protrusions 12a and 12b are in sliding contact with the surface of the first yoke 6 and the second protrusions 13a and 13b are in sliding contact with the surface of the second yoke 7, respectively. Therefore, the play of the holder 10 can be prevented and a stable movement of the holder 10 can be obtained. As a result, since two parallel guide rails are not required as in the prior art, the linear actuator 1 can be easily downsized with a simple configuration.

  Further, since the first protrusions 12a and 12b of the holder 10 are dropped into the guide groove 15 and slide along the longitudinal direction of the guide groove 15, the movement of the holder 10 can be further stabilized, Since the space considering the thickness of the magnet array 9 and the thickness of the holder 10 (or the air-core coils 8A and 8B) may be secured between the first yoke 6 and the second yoke 7, the linear actuator 1 Can be made thinner. Further, by using the guide rail 5, the first protrusions 12a and 12b and the second protrusions 13a and 13b do not come into contact with the magnet array 9, so that the holder 10 can be moved smoothly. You can also.

  Here, due to the interaction between the current generated when the air core coils 8A and 8B are energized and the magnetic field generated between the N pole of the magnet 9a and the S pole of the magnet 9b, the air core coils 8A and 8B A driving force is generated in the longitudinal direction of the magnet row 9, and the holder 10 holding the air-core coils 8A and 8B is moved along the longitudinal direction of the magnet row 9 by the guide rail 5 and the projections 12a, 12b, 13a and 13b. Moves stably and smoothly. Further, by using the air-core coils 8A and 8B in the linear actuator 1, the air-core coils 8A and 8B are not subjected to cogging thrust, so that the controllability of the linear actuator 1 is improved. The linear actuator 1 is suitable for microstep driving that enables subdivision of the step distance.

  The present invention is not limited to the above embodiment. For example, the shapes of the first protrusions 12a and 12b and the second protrusions 13a and 13b are substantially rectangular parallelepipeds and cylinders, respectively, but are not limited thereto, and may be spherical or other shapes.

It is a top view of the linear actuator which concerns on this invention. It is sectional drawing along the II-II line of FIG. It is sectional drawing along the III-III line of FIG. It is a top view of a linear actuator in the state where the 2nd yoke was removed. It is a perspective view which shows a holder and an air-core coil. It is a perspective view which shows a holder and an air-core coil. It is sectional drawing along the VII-VII line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Linear actuator, 6 ... 1st yoke (1st magnetic body), 7 ... 2nd yoke (2nd magnetic body), 8A, 8B ... Air-core coil, 9a, 9b ... Magnet, 10 ... Holder , 11 ... body part, 12a, 12b ... first projection part, 13a, 13b ... second projection part.

Claims (2)

A first magnetic body and a second magnetic body which are formed in an elongated shape and face each other in the thickness direction;
It is disposed between the first magnetic body and the second magnetic body, and is fixed to at least one of the first magnetic body and the second magnetic body, and the polarities are alternately different in the longitudinal direction. A plurality of magnets arranged side by side,
An air-core coil that faces the magnet between the first magnetic body and the second magnetic body and is movably installed in the longitudinal direction;
A main body holding the air-core coil, a holder having a first protrusion and a second protrusion protruding from the main body toward the first magnetic body and the second magnetic body;
A linear actuator comprising: The first protrusion and the second protrusion are separated from the magnet and are in sliding contact with the surfaces of the first magnetic body and the second magnetic body, respectively. The linear actuator according to 1.

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