JP2006149001A - Sensor integrated linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a configuration of a servo drive device, to reduce parts, and to reduce the size by integrating a linear motor composed of a strong magnet and a moving coil and a position detection sensor.
A stator having a pair of opposed surfaces that are opposed to each other via a gap having a predetermined width and that generates a magnetic field in a direction perpendicular to the opposed surface. A hollow movable coil 15 disposed in the gap of the stator and linearly driven in the direction along the gap in the gap by supplying a driving current, and disposed in a hollow portion of the hollow movable coil 15 And a position detection element that detects the magnetic field in the stator and detects the position of the hollow movable coil to constitute a sensor-integrated linear motor.
[Selection] Figure 1

Description

  The present invention relates to a sensor-integrated linear motor, and is used in, for example, a servo drive device for offsetting a small optical component from an optical axis. By integrating a position detection sensor with a linear motor, the component of the servo drive device is used. The present invention relates to a sensor-integrated linear motor that can simultaneously achieve reduction and space saving.

In order to drive a servo such as an optical component using a linear motor including a fixed yoke having a strong magnet and a moving coil, a position detection sensor for detecting the position of the optical component in addition to the linear motor is provided. Separately needed. As a position detection sensor, generally, a combination of a Hall element, a magnetoresistive element and a permanent magnet, a combination of PSD (Position Sensitive Device) and LED (light emitting diode), a linear encoder, etc. are used. A signal indicating position information of the driven member is obtained. A signal indicating the position information is fed back to the drive unit including the linear motor to servo-drive the driven member to a desired position. Therefore, such a servo drive device includes a drive unit such as a linear motor and a detection unit such as a position detection sensor.
JP 05-68364 A

  However, the conventional configuration described above has a disadvantage in that the configuration of the apparatus is complicated and the size of the apparatus is increased because a drive unit composed of a linear motor and a detection unit having, for example, a Hall element and a permanent magnet are provided separately. It was. In addition, since separate permanent magnets are used for the drive unit and the detection unit, the number of parts increases, which is a limitation in reducing the size and cost of the apparatus.

  Accordingly, an object of the present invention is to reduce the size of the entire servo drive device including the drive unit and the detection unit and save space based on the concept of arranging the position detection sensor inside the hollow portion of the movable coil. .

  Another object of the present invention is to reduce the number of parts of the servo drive device and reduce the cost by integrating the drive unit and the detection unit.

  According to one aspect of the present invention, a permanent magnet and an iron core portion are provided, and a pair of opposing surfaces are provided to face each other with a gap having a predetermined width, and a magnetic field is perpendicular to the opposing surfaces in the gap. A stator to be generated, a hollow movable coil disposed in the gap of the stator and linearly driven in the direction along the gap in the gap by supplying a driving current; and a hollow portion of the hollow movable coil And a position detecting element that is fixed to the hollow movable coil and detects the position of the hollow movable coil by detecting the magnetic field in the stator. Is provided.

  In this case, it is advantageous that the magnetic fields in the stator are generated in opposite directions with respect to an intermediate portion of the moving stroke of the movable coil.

  Further, the iron core portion of the stator has a U-shape including a pair of opposing surfaces, and a plate-like permanent magnet can be attached to at least one of the opposing surfaces.

  The plate-like permanent magnets are magnetized in the thickness direction, and it is convenient that the magnetization directions are magnetized in opposite directions with respect to the central portion of the plate-like region.

  The hollow movable coil has a flat shape having parallel opposite sides, and can be configured to move in the direction perpendicular to the parallel opposite sides and along the gap.

  The position detection element may be a Hall element.

  According to another aspect of the present invention, two sensor-integrated linear motors are used, and the hollow movable coils of the two sensor-integrated linear motors are moved to a common plate-shaped movable member so that their moving directions are perpendicular to each other. A linear motor integrated with a two-dimensional drive sensor is provided, wherein the plate-like movable member is two-dimensionally driven.

  According to the present invention, in the servo drive device, not only can the space for the position detection sensor conventionally required be eliminated, but also the sensor magnet is unnecessary, and the entire servo drive device including the drive unit and the detection unit can be obtained. The size can be reduced only to the space of the conventional drive device. Therefore, the number of parts of the servo drive device can be reduced and the price can be reduced, and the configuration of the device can be simplified and the entire servo drive device can be downsized. Further, not only can the entire servo drive device be reduced in size and space can be saved, but also the reliability of the device can be improved by simplifying the configuration of the servo drive device portion.

  Prior to describing preferred embodiments of the present invention, an outline of a conventional linear motor, a position detection sensor, and a servo drive device including these will be described.

  FIG. 3 shows an example of a conventional linear motor. FIG. 3A is a side view of the linear motor, FIG. 3B is a front view, and FIG. 3C is used for the linear motor. The structure of a permanent magnet is shown.

  As shown in these drawings, the conventional linear motor includes a fixed yoke 31 made of a U-shaped iron core, permanent magnets 33 attached to opposing surfaces inside the fixed yoke 31, and a fixed yoke. A hollow movable coil 35 is provided so as to be movable in a gap of a stator composed of 31 and a permanent magnet 33.

  As shown in FIG. 3C, the permanent magnet 33 is configured by a plate-like, for example, square strong magnet. The permanent magnet 33 is magnetized in the thickness direction, and the directions of magnetization are magnetized in opposite directions with respect to the central portion of the plate-like region.

  By sticking such a permanent magnet 33 to the inner facing surface of the fixed yoke 31 in the magnetization direction shown in FIG. 3A, the magnetic field in the stator borders the intermediate part of the moving process of the movable coil 35. Are generated in directions opposite to each other and in a direction perpendicular to the gap in the stator.

  Therefore, when the hollow movable coil 35 is arranged as shown in the stator having such a magnetic field and a current is passed through the hollow movable coil 35, the hollow movable coil 35 is changed in accordance with the direction of the current. Driven in the direction indicated by the arrow 3 (b). As a result, a driven member (not shown) fixed to the hollow movable coil 35 can be linearly driven.

  As shown in FIGS. 4A and 4B, the stator may be attached only to one of the opposing surfaces inside the U-shaped fixed yoke 31a. Even in such a configuration, a desired magnetic field can be generated in the stator in a direction perpendicular to the gap in the stator, and the operation as a linear motor can be performed as in the configuration of FIG.

  FIG. 5 shows an outline of an optical axis correction device that uses two linear motors shown in FIG. 4 to shift the correction lens in order to perform image alignment of the imaging device or camera shake correction, for example. The structure of is shown. The apparatus shown in the figure includes a correction lens 51 that is driven to shift substantially perpendicular to the optical axis to shift the optical axis. The correction lens 51 is attached to the hole of the plate-like driven member 53. The driven member 53 is mechanically fixed to the movable coils 55a and 57a of the two linear motors 55 and 57. The linear motors 55 and 57 are arranged such that the movable coils 55a and 57a drive the driven member 53 in directions perpendicular to each other as indicated by arrows in FIG. As a result, it is possible to drive the driven member 53 in the direction indicated by the arrow in FIG. 5, that is, to drive it in a two-dimensional manner, by passing a necessary current through the movable coils 55a and 57a of the linear motors 55 and 57. it can.

  The driven member 53 is provided with two position detection sensors 59 and 61 for detecting the position of the driven member 53. Each position detection sensor 59 and 61 is arranged to detect a movement position in a direction perpendicular to each other.

  The position detection sensor 59 includes a hall element 59a fixed to the driven member 53, and a permanent magnet 59b arranged to face the hall element via a predetermined gap. The permanent magnet 59b is a plate-like permanent magnet, which is magnetized in the thickness direction, and the magnetizing directions are magnetized in opposite directions with respect to the central portion of the plate-like member.

  Similarly, the other position detection sensor 61 includes a hall element 61a fixed to the driven member 53, and a similar permanent magnet 61b facing the hall element 61a with a predetermined gap. However, the position detection sensors 59 and 61 are arranged so that the arrangement directions of the Hall elements and the attachment directions of the permanent magnets 59b and 61b are perpendicular to each other.

  With such a configuration, in the apparatus of FIG. 5, the correction lens 51 is two-dimensionally driven in the direction perpendicular to the optical axis by the two linear motors 55 and 57. Then, the position detection sensors 59 and 61 detect the deviation of the correction lens 51 from the optical axis, and are fed back to a drive circuit (not shown) so as to have a desired deviation, for example, and are necessary for the movable coils of the linear motors 55 and 57 Supply the correct drive current. As a result, the correction lens 51 can be servo-driven to a desired position in a direction perpendicular to the optical axis.

  In the conventional optical axis correction apparatus as described above, since the position detection sensors 59 and 61 are provided separately from the linear motors 55 and 57 as described above, the apparatus is increased in size and the number of parts is reduced. There was an inconvenience that it was not possible.

  Next, a preferred embodiment of a sensor-integrated linear motor according to a preferred embodiment of the present invention and an optical axis correction device as an example of a device using the same will be described.

  FIG. 1 shows a schematic configuration of a sensor-integrated linear motor according to an embodiment of the present invention. (A) is a side view of the sensor-integrated linear motor, (b) is a front view, and (c) is an explanation showing the configuration of a permanent magnet used in the sensor-integrated linear motor. FIG. 4D is an explanatory diagram showing an example of a Hall element as a position detection element used in the sensor-integrated linear motor.

  As shown in these drawings, a sensor integrated linear motor according to an embodiment of the present invention is attached to one of a fixed yoke 11 made of a U-shaped iron core and an opposing surface inside the fixed yoke 11. And a permanent magnet 13 attached thereto. A hollow movable coil 15 is movably disposed in the gap of the stator formed by the fixed yoke 11 and the permanent magnet 13. A Hall element 17 is fixed to the hollow portion of the hollow movable coil 15. The Hall element 17 and the hollow movable coil 15 are configured to have a thickness smaller than the width of the gap so as to be movable within the gap of the stator. For example, as shown in the drawing, the hollow movable coil 15 is a thin coil wound in a flat rectangular shape, and a thin Hall element 17 is attached to the center of the coil. That is, the hollow movable coil 15 has a flat shape having parallel opposite sides, and is driven in a direction perpendicular to the parallel opposite sides within the gap of the stator.

  As shown in FIG. 1C, the permanent magnet 13 is configured by a plate-shaped, for example, square strong magnet. The permanent magnet 13 is magnetized in the thickness direction, and the magnetizing directions are magnetized in opposite directions with respect to the central portion of the plate-like region.

  By sticking such a permanent magnet 13 to one of the opposed surfaces inside the fixed yoke 11 in the magnetization direction shown in FIG. 1A, the magnetic field in the stator is an intermediate part of the moving process of the movable coil 15. Are generated in directions opposite to each other and perpendicular to a gap in the stator.

  FIG. 1D shows an example of the configuration of the Hall element 17. The Hall element 17 includes, for example, a pair of input terminals for supplying a predetermined direct current and a pair of output terminals for outputting a voltage generated according to a magnetic field applied to the Hall element. These input terminals and output terminals, or the 17 package portions of the Hall elements, are fixed to the hollow movable coil 15. Alternatively, the Hall element 17 and the hollow movable coil 15 may be integrated by resin molding.

  The position detection element in the present invention is not limited to the Hall element, and for example, a magnetoresistive element or any other element that can detect a magnetic field can be used.

  When the hollow movable coil 15 having the Hall element 17 attached is arranged as shown in the stator having the magnetic field as described above and a current is passed through the hollow movable coil 15, the hollow movable coil 15 has a current direction. In response to this, it is driven in the direction indicated by the arrow in FIG. As a result, a driven member (not shown) attached to the hollow movable coil 15 can be linearly driven.

  The Hall element 17 generates an output voltage according to the magnetic field in the stator, and this output voltage varies according to the position of the hollow movable coil 15 in the stator. Therefore, the output voltage of the Hall element 17 can be used as a position detection signal of the hollow movable coil 15, and this signal can be fed back to flow a desired current through the hollow movable coil 15 to perform servo drive.

  In order to drive the hollow movable coil 15, a drive current is passed through the hollow movable coil 15, so that the Hall element 17 may be affected by a magnetic field due to the coil current of the hollow movable coil 15. However, since the magnetic field generated by the permanent magnet 13 is stronger than the magnetic field generated by the hollow movable coil 15, the influence of the coil current is small, and further, since the servo is applied, the influence becomes almost unknown. In fact, the inventor of the present application prototyped this sensor-integrated linear motor to perform servo operation, but no problem occurred.

  FIG. 2 shows an optical axis correction apparatus that uses two sensor-integrated linear motors shown in FIG. 1 to shift a correction lens in order to perform image alignment of an imaging apparatus or camera shake correction, for example. A schematic configuration is shown. The apparatus shown in the figure includes a correction lens 21 that is driven to shift substantially perpendicular to the optical axis to shift the optical axis. The correction lens 21 is attached to the hole of the plate-like driven member 23. The driven member 23 is mechanically fixed to the hollow movable coils 25 a and 27 a of the two sensor integrated linear motors 25 and 27. Each of the sensor-integrated linear motors 25 and 27 is arranged such that the hollow movable coils 25a and 27a drive the driven member 23 in directions perpendicular to each other as indicated by arrows in FIG. As a result, the driven member 23 is driven in the direction indicated by the arrow in FIG. 2 by flowing a necessary current through the hollow movable coils 25a and 27a of the sensor-integrated linear motors 25 and 27, that is, two-dimensionally. Can be driven.

  Further, in each of the sensor-integrated linear motors 25 and 27, position detecting elements, in this embodiment, Hall elements 25b and 27b, are attached to the respective hollow movable coils 25a and 27a. Each position detection element 25b and 27b is arranged to detect a movement position in a direction perpendicular to each other.

  Hall elements constituting the position detection elements 25b and 27b are located in the stators of the sensor-integrated linear motors 25 and 27, and generate magnetic fields generated by plate-like permanent magnets attached to the stators. In response, a voltage is output. Thereby, each position detection element 25b and 27b outputs a position detection signal corresponding to the position in the stator of the hollow movable coils 25a and 27a of the respective sensor integrated linear motors 25 and 27.

  With such a configuration, in the apparatus of FIG. 2, the correction lens 21 is driven two-dimensionally in the direction perpendicular to the optical axis by the two sensor-integrated linear motors 25 and 27. Then, the position detection elements 25b and 27b built in the sensor-integrated linear motors 25 and 27 detect the deviation of the correction lens 21 from the optical axis and feed back to a drive circuit (not shown) so as to obtain a desired deviation, for example. Then, a necessary drive current is supplied to the hollow movable coils 25a and 27a of the sensor-integrated linear motors 25 and 27. As a result, the correction lens 21 can be servo-driven to a desired position in a direction perpendicular to the optical axis.

  The present invention relates to an optical axis correction device that shifts a small correction lens, for example, for image alignment of an image pickup device or camera shake correction, or a device that servo-drives a small member to a desired position, etc. It is applicable to.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows schematic structure of the sensor integrated linear motor concerning one Embodiment of this invention, The figure (a) is a side view, The figure (b) is a front view, The figure (c) is this sensor. An explanatory view of a permanent magnet used in the integrated linear motor, and FIG. 4D is an explanatory view of a Hall element used in the sensor integrated linear motor. It is explanatory drawing which shows the general | schematic structure of the optical axis correction apparatus using the sensor integrated linear motor concerning this invention. It is explanatory drawing which shows an example of the conventional linear motor, The figure (a) is a side view of this linear motor, The figure (b) is a front view, The figure (c) is used for this linear motor. It is explanatory drawing which shows the structure of a permanent magnet. It is explanatory drawing which shows the other example of the conventional linear motor, The figure (a) is a side view, The figure (b) is a front view. It is explanatory drawing which shows the schematic structure of the optical axis correction apparatus using the conventional linear motor.

Explanation of symbols

11, 31 Fixed yoke 13, 33 Permanent magnet 15, 35 Hollow movable coil 17, 25b, 27b Position detecting element 21, 51 Correction lens 23, 53 Driven member 25, 27, 55, 57 Linear motor 25a, 27a, 55a, 57a Hollow movable coil 59, 61 Position detection sensor

Claims (7)

A stator including a permanent magnet and an iron core, and having a pair of opposed surfaces facing each other with a gap having a predetermined width, and generating a magnetic field in the gap in a direction perpendicular to the opposed surface;
A hollow movable coil disposed within the gap of the stator and linearly driven in the direction along the gap in the gap by supplying a driving current;
A position detecting element that is disposed in a hollow portion of the hollow movable coil and is fixed to the hollow movable coil, and detects a magnetic field in the stator to detect a position of the hollow movable coil;
A linear motor with an integrated sensor.   2. The sensor-integrated linear motor according to claim 1, wherein the magnetic field in the stator is generated in opposite directions with respect to an intermediate portion of the moving stroke of the movable coil.   The iron core portion of the stator has a U-shape including a pair of opposing surfaces, and a plate-like permanent magnet is attached to at least one of the opposing surfaces. Sensor-integrated linear motor as described.   4. The sensor according to claim 3, wherein the plate-like permanent magnets are magnetized in the thickness direction, and the magnetization directions are magnetized in opposite directions with respect to a central portion of the plate-like region. Integrated linear motor.   The hollow movable coil has a flat shape having parallel opposite sides, and moves in the direction perpendicular to the parallel opposite sides and along the gap in the gap. Sensor integrated linear motor.   The sensor-integrated linear motor according to claim 1, wherein the position detection element is a Hall element. Two sensor-integrated linear motors according to any one of claims 1 to 6 are used, and the hollow movable coils of the two sensor-integrated linear motors are moved to a common plate-shaped movable member so that their moving directions are perpendicular to each other. A linear motor integrated with a two-dimensional drive sensor, wherein the plate-shaped movable member is two-dimensionally driven.

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