JP2006136049A - Linear motor, stator holding structure of linear motor, and radiation image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor in which a stator can be attached removably by work from one end, and to provide the stator holding structure of the linear motor, and a radiation image reader. <P>SOLUTION: The linear motor 10 comprises a stator 20 having a plurality of magnets 24 contained in a pipe-like member 21 and held by holding structures at both ends thereof, and a moving element 30 inserted with the stator 20 in the center. Since one end 22 of the stator 20 is formed into a screw shape, the stator 20 can be fixed to the holding structure by inserting the stator 20 from one holding structure toward the other holding structure and then screwing the screw-shaped end to either of the holding structure while rotating the stator 20 in the radial direction, and the stator 20 can be removed from the holding structure by rotating the stator 20 reversely. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a linear motor, a stator holding structure of the linear motor, and a radiation image reading apparatus.

  It has been proposed to use a linear motor for parts that require conveyance accuracy, such as print heads and exposure operation heads in OA equipment, and exposure operation means in medical equipment. One example of a device that uses a linear motor is a radiation image reading apparatus.

  Radiation images such as X-ray images are often used for disease diagnosis and the like. Conventionally, in order to obtain such a radiographic image, X-rays that have passed through a subject are irradiated onto a phosphor layer (fluorescent screen), thereby generating visible light and taking a normal picture of this visible light. Similarly, so-called radiographs in which a film using a silver salt was irradiated and developed were used. However, in recent years, a technique has been devised for extracting an image directly from a phosphor layer without using a film coated with silver salt.

  As an example of this method, radiation that has passed through a subject such as a patient is absorbed by the phosphor, and then the phosphor is accumulated by the above absorption by exciting the phosphor with, for example, light or thermal energy. Some radiation energy is emitted as fluorescence, and this fluorescence is detected and imaged. A stimulable phosphor plate having a photostimulable phosphor layer formed on a support is used. The stimulable phosphor layer of this stimulable phosphor plate is irradiated with radiation transmitted through the subject, Radiation energy corresponding to the radiation transmittance of each part is accumulated to form a latent image, and then the stimulable phosphor layer is scanned with stimulated excitation light to radiate the accumulated radiation energy of each part. Then, this is converted into light, and the intensity of this light is converted into an image signal via a photoelectric conversion means such as a photomultiplier to obtain a radiation image as digital image data.

  Based on such digital image data, an image is formed on a silver salt film, or an image is output to a CRT or the like for visualization. The digital image data is stored in an image storage device such as a semiconductor storage device, a magnetic storage device, or an optical disk storage device, and then taken out from the image storage device as necessary, via a silver salt film, a CRT, or the like. Can be visualized.

  By the way, when the photostimulable phosphor plate is scanned with the photostimulable excitation light, the image reading unit (optical unit) must be precisely moved relative to the photostimulable phosphor plate at a constant speed. That is, constant speed is required in the conveyance body, and it is necessary to perform high-performance speed control.

  For this reason, in the prior art, there is a linear motor as a driving source for the conveyance body, and an image reading apparatus that moves the stimulable phosphor plate relative to the image reading unit while guiding the stimulable phosphor plate by the guide member. It is known, and thereby the carrier is moved smoothly (see, for example, Patent Document 1).

  As a linear motor, for example, as described in Patent Document 2 and the like, a cylindrical magnet having a through hole at the center is used, and the central axis is passed through the through holes of a plurality of cylindrical magnets. There is a shaft type linear motor in which a stator (shaft) is created by insertion, and a mover including a coil is movably disposed along the stator. Such a shaft-type linear motor is suitable for precision conveyance in OA equipment and the like in terms of speed performance and space saving, compared to a linear motor using a conventional flat magnet.

When holding a round bar-shaped member such as a stator, the member is generally sandwiched in a radial direction using a V block or the like and held so as to be tightened. For example, as shown in Patent Document 3, a mounting member is provided at both ends of the stator, and a flange that supports the mounting member is provided in the apparatus, and the flange holds the mounting member at an arbitrary position in the axial direction of the stator. Some are able to do this and fix the stator to the device like a stick.
JP 2003-248276 A Japanese Patent Laid-Open No. 10-313566 JP-A-10-136175

  However, in the method of holding the stator in a radial direction by using a V-block or the like and holding the stator in place, or the method of fixing the stator to the device like a tension rod, a force that causes bending or warping of the stator is applied. . In the linear motor, the clearance (gap) between the stator and the mover is made small in order to obtain thrust efficiently, but if the stator bends or warps, the contact between the stator and the mover is caused. There is a risk of deteriorating the conveyance performance. For this reason, management of fine tightening torque is required, and workability is not good.

  In addition, in a radiation image reading apparatus or the like, a conveyance object such as an optical unit or a linear encoder that measures the displacement of the linear motor is disposed around the linear motor, and the stator is inserted through the movable element. Therefore, when performing the attaching / detaching operation of only the stator, the stator will be moved in the axial direction, but in the method of holding the stator to be tightened or fixing the stator to the device like a tension rod, Work at both ends of the stator is necessary, and the configuration of parts becomes complicated, so that workability and productivity are not good.

  An object of the present invention is to provide a linear motor in which the stator is not subjected to a force that causes bending or warping, and the stator can be easily attached and detached by work from one end, and a stator holding structure of the linear motor And a radiation image reading apparatus including a linear motor.

  In order to solve the above problems, the invention according to claim 1 is configured such that, for example, as shown in FIGS. 1 to 3, a plurality of magnets 24 are housed in a pipe-like member 21 and held by holding structures at both ends. In the linear motor 10 including the stator 20 and the movable element 30 through which the stator 20 is inserted in the center, one end portion (screw portion 22) of the stator 20 is formed in a screw shape. It is characterized by that.

  According to the first aspect of the present invention, since one end of the stator 20 is formed in a screw shape, the stator 20 is inserted from one of the holding structures toward the other, and the stator 20 While rotating the screw in the radial direction, the screw-shaped end portion (screw portion 22) is screwed into one of the holding structures (screw hole 43) to attach the stator 20 to the holding structure, and the stator 20 is reversed. By rotating in the direction, the stator 20 can be removed from the holding structure. Therefore, the stator 20 can be attached to and detached from the holding structure without applying a force that causes bending or warping to the stator 20.

  Invention of Claim 2 is the linear motor 10 of Claim 1, Comprising: The outer diameter of the said screw shape (screw part 22) is larger than the outer diameter of the other part of the stator 20. And

  According to the second aspect of the present invention, since the outer diameter of the screw shape (screw part 22) is larger than the outer diameter of the other part of the stator 20, the stator 20 is removed from the other end (cap 23). It is inserted into one of the holding structures (screw hole 43) and engaged with the other of the holding structure (engagement hole 44), and the screw shape (screw portion 22) is screwed into one of the holding structures (screw hole 43). Thus, the stator 20 can be held.

  Invention of Claim 3 is the linear motor 10 of Claim 1, Comprising: The outer diameter of the said screw shape (screw part 22) is smaller than the outer diameter of the other part of the stator 20. And

  According to the invention described in claim 3, since the outer diameter of the screw shape (screw portion 22) is smaller than the outer diameter of the other portion of the stator 20, the stator 20 is held from the screw shape (screw portion 22). Insert into one of the structures (engagement hole 44) and screw into the other (screw hole 43) of the holding structure, and engage the other end (cap 23) with one (engagement hole 44) of the holding structure Thus, the stator 20 can be held.

  Invention of Claim 4 is the linear motor 10 as described in any one of Claims 1-3, Comprising: With the tool which rotates the stator 20 to radial direction at least one end of the said stator 20 Engagement parts (slots 25 and 26) are provided.

  According to the fourth aspect of the present invention, the stator can be rotated in the radial direction by engaging the tool with the engaging portion.

  A fifth aspect of the present invention is the linear motor 10 according to any one of the first to fourth aspects, wherein the outer shape of the magnet 24 is a cylindrical shape.

  Here, the outer shape of the magnet having a columnar shape includes, for example, a cylindrical magnet having a through hole in the center. According to the fifth aspect of the present invention, since the outer shape of the magnet 24 is a columnar shape, the magnet 24 can be efficiently accommodated inside the cylindrical pipe-shaped member 21.

  A sixth aspect of the present invention is the linear motor 10 according to any one of the first to fifth aspects, wherein the magnet 24 is a rare earth magnet.

  According to the sixth aspect of the present invention, by using a rare earth magnet having a strong magnetic force, it is possible to obtain a high thrust as compared with other magnets. The motor 10 can be reduced in size.

  The invention according to claim 7 is the stator holding structure for the linear motor 10 according to any one of claims 1 to 6, wherein one end portion (screw) of the stator 20 formed in a screw shape is provided. A first holding portion (screw holding portion 41) provided with a screw hole 43 to be engaged with the portion 22), and an engagement hole 44 to be engaged with the other end portion (cap 23) of the stator 20. And a second holding part (cap holding part 42).

  According to the invention described in claim 7, the first holding portion (screw holding portion 41) provided with the screw hole 43 and the engagement hole 44 engaged with the other end portion of the stator 20 are provided. The stator 20 is inserted from one of the second holding portions (cap holding portion 42) toward the other, and the screw shape is changed to the screw hole of the first holding portion while rotating the stator 20 in the radial direction. The stator 20 can be attached to the holding structure by being screwed to 43 and engaging the other end with the engaging hole 44 of the second holding portion. Moreover, the stator 20 can be removed from the holding structure by rotating the stator 20 in the opposite direction.

  The invention described in claim 8 is the stator holding structure of the linear motor 10 described in claim 7, characterized in that the inner diameter of the screw hole 43 is smaller than the inner diameter of the engagement hole 44.

  According to the invention described in claim 8, since the inner diameter of the screw hole 43 is smaller than the inner diameter of the engagement hole 44, the stator 20 is engaged from one end portion (screw portion 22) formed in a screw shape. The stator 20 can be attached to the holding structure by inserting into the hole 44 and screwing the screw shape with the screw hole 43 and engaging the other end (cap 23) with the engagement hole 44.

  A ninth aspect of the present invention is the stator holding structure for the linear motor 10 according to the seventh aspect, wherein the inner diameter of the screw hole 43 is larger than the inner diameter of the engagement hole 44.

  According to the ninth aspect of the present invention, since the inner diameter of the screw hole 43 is larger than the inner diameter of the engagement hole 44, the end of the stator 20 opposite to the end portion (screw portion 22) formed in a screw shape. The stator 20 can be attached to the holding structure by inserting into the screw hole 43 from the portion (cap 23), engaging the end with the engagement hole 44, and screwing the screw shape with the screw hole 43.

  According to a tenth aspect of the present invention, in the radiation image reading apparatus 1 that scans the photostimulable phosphor panel with the optical unit 5, the drive source that conveys the optical unit 5 or the photostimulable phosphor panel is used in the first to sixth aspects. The linear motor 10 described in any one of the above is used.

  According to the invention described in claim 10, since the radiation image reading apparatus 1 drives the optical unit 5 by the linear motor 10 according to any one of claims 1 to 6, the stator 20 of the linear motor 10 is used. It is possible to provide the radiation image reading apparatus 1 that can be easily attached and detached by work from one end.

  According to the present invention, the linear motor stator can be easily attached and detached by rotating the linear motor stator in the radial direction with a simple configuration in which one end of the stator is formed in a screw shape. This eliminates the need for fine tightening torque management and improves workability. For this reason, the stator does not bend or warp when the stator is attached or detached. Therefore, there is no possibility that the stator and the movable element come into contact with each other and the conveyance performance is not impaired.

  Hereinafter, although an embodiment of the present invention is described, the present invention is not limited to this embodiment.

  FIG. 1 shows a radiation image reading apparatus 1 to which the present invention is applied. The radiation image reading apparatus 1 includes an optical unit 5, a carriage 3, a linear motor 10, a linear motion guide 4, a linear encoder 7, and a plate support portion 6 as main components, a base 2 that supports them, and these. The outer cover 8 is generally configured. In the present embodiment, the radiation image reading apparatus 1 configured to transport the optical unit 5 by the linear motor 10 will be described. However, the present invention is not limited to this, and the stimulable phosphor plate 9 described later is transported. It is good also as a structure.

  A linear motor 10, a transport table 3, a linear motion guide 4, a linear encoder 7, an optical unit 5, a plate support portion 6, and the like are provided on the base 2.

  The linear motor 10 includes a rod-shaped stator 20 and a mover 30. The stator 20 houses a plurality of magnets 24 inside a pipe-shaped member 21 so that adjacent magnets 24 are repelled from each other, and both ends are held by a stator holding part 40 and parallel to the base 2. It is fixed. The stator 20 is inserted through the center of the mover 30. A structure for attaching the stator 20 to the stator holding portion 40 will be described later.

  The mover 30 is fixed to the lower surface of the transport table 3. A coil is housed inside the mover 30. As the coil, a coil group composed of a plurality of phases, for example, three phases can be used, but is not limited thereto. Further, the mover 30 is provided with an insertion hole through which the stator 20 is inserted. When a current is passed through the coil, the mover 30 obtains a magnetic force repelling the magnet 24 housed in the stator 20 and moves in the axial direction of the stator 20.

  The carriage 3 supports the optical unit 5 and moves in the axial direction of the stator 20 together with the mover 30 fixed to the lower surface. The linear motion guide 4 is disposed on the base 2 in parallel with the stator 20 and assists the movement of the transport table 3. The linear encoder 7 includes a scale 71 disposed on the base 2 in parallel with the stator 20, and a head 72 that is provided on the transport table 3 and moves along the scale 71 while maintaining a constant interval. The linear encoder 7 measures the position of the transport table 3.

  The optical unit 5 includes a laser light irradiation device (not shown) that irradiates the stimulable phosphor plate 9 while scanning the laser light in a direction orthogonal to the moving direction of the optical unit 5, and a laser light irradiation device. A light guide plate 51 that guides the stimulated emission light excited by irradiating the photostimulable phosphor plate 9 with laser light, and a condenser tube 52 that collects the stimulated emission light guided by the light guide plate 51, And a photoelectric converter 53 that converts the photostimulated luminescent light collected by the condenser tube 52 into an electrical signal.

  In the image reading apparatus of the present invention, although not shown, the photostimulable phosphor is used to release the radiation energy remaining on the photostimulable phosphor plate 9 after the radiation energy is read by the optical unit 5. An erasing device for irradiating the plate 9 with erasing light is provided.

  The plate support 6 supports the photostimulable phosphor plate 9 obtained by X-ray photography in parallel with the direction in which the optical unit 5 moves. The photostimulable phosphor plate 9 records a latent image transmitted by X-ray imaging, and emits stimulated emission light corresponding to the dose when irradiated with laser light from a laser beam irradiation device. The photostimulated emission light is photoelectrically converted by the photoelectric converter 53 to obtain digital image data. The obtained digital image data can be visualized as a radiation image by appropriate means.

The exterior cover 8 is provided so as to cover these devices. The exterior cover 8 is provided with a loading / discharging port 81 for loading or discharging the stimulable phosphor plate 9 into the apparatus.
Further, the outer cover 8 is provided with a stator attaching / detaching port 82 for taking out the stator 20 for inspection and inserting it again.

  Next, the stator 20 of the linear motor 10 and the stator holder 40 that fixes the stator 20 will be described in more detail. As shown in FIG. 2A, the stator 20 includes a plurality of magnets 24 and a pipe-like member 21 that houses the plurality of magnets 24.

  The magnet 24 is preferably cylindrical so that it can be efficiently accommodated in the pipe-shaped member 21. However, if the outer shape is cylindrical, a cylindrical magnet having a through hole in the center may be used. . The material of the magnet 24 is preferably a rare earth magnet having a high magnetic flux density. In particular, the rare earth magnet is preferably a neodymium-based magnet, such as a neodymium-iron-boron magnet (Nd-Fe-B magnet), and can provide a higher thrust than other magnets.

  As a material of the pipe-like member 21, it is preferable to use a nonmagnetic material such as an aluminum alloy, a copper alloy, or nonmagnetic stainless steel. Moreover, it is preferable that the pipe-shaped member 21 is as thin as possible so as not to reduce the magnetic field applied to the mover 30 disposed on the outside thereof. For example, the pipe-shaped member 21 having a thickness of about 1 mm can be formed using stainless steel.

  One end of the pipe-shaped member 21 is closed, and a screw portion 22 is provided integrally. Further, the other end of the pipe-shaped member 21 is opened to accommodate the magnet 24 in the pipe-shaped member 21, and a cap 23 for closing the opening is provided. The cap 23 can be formed using a nonmagnetic material similar to that of the pipe-shaped member 21.

Inside the pipe-shaped member 21, a plurality of magnets 24 are accommodated with the same magnetic poles facing each other so as to repel each other. In FIG. 2A, the adjacent magnets 24 are stored inside the pipe-shaped member 21 so that the adjacent magnets 24 are in close contact with each other. You may accommodate so that a clearance gap may be provided between the magnets 24 which fit.
The cap 23 restricts the magnet 24 from coming out of both ends of the pipe-like member 21 due to the repulsive force.

  The stator holding part 40 includes a screw holding part 41 and a cap holding part 42, and each is fixed to the base 2. The screw holding portion 41 has a screw hole 43 to be screwed with the screw portion 22. The cap holding part 42 has an engagement hole 44 that engages with the cap 23. The inner diameter of the screw hole 43 is equal to the outer diameter of the screw portion 22, and the inner diameter of the engagement hole 44 is equal to the outer diameter of the cap 23.

  As described below, the screw portion 22 and the screw holding portion 41 are (1) when the outer diameter of the screw portion 22 is larger than other portions of the pipe-shaped member 21 (FIG. 2), and (2) the screw portion 22. When the outer diameter is smaller than the other part of the pipe-shaped member 21 (FIG. 3), two types of forms can be taken. Depending on this form, the method of attaching the stator 20 to the apparatus and removing it from the apparatus are different. FIG. 1 shows the case (1).

(1) When the outer diameter of the screw part 22 is larger than the other part of the pipe-like member 21 The screw holding part 41 is arranged on the side closer to the stator attaching / detaching port 82 in FIG. 1, and the cap holding part 42 is arranged on the far side. Is done. The inner diameter of the screw hole 43 is larger than the other part of the pipe-shaped member 21 as shown in FIG. The engaging hole 44 does not penetrate the cap holding portion 42, and the position of the stator 20 is determined by the tip of the cap 23 coming into contact with the inner surface of the engaging hole 44.

  The screw portion 22 is provided with an engaging portion that engages with a tool (driver, wrench, etc.) that rotates the stator 20. In FIG. 2A, a slot 25 that engages with a flat-blade screwdriver is shown as an engaging portion, but the shape of the engaging portion can maintain a firm engaging relationship with the tool to be used. If so, it may be arbitrarily changed depending on usability. For example, a hexagonal hole that engages with a hexagon wrench may be provided. Alternatively, a cross-shaped groove that engages with a Phillips screwdriver may be provided, or, for example, a star-shaped hole that engages with a star-shaped engaging tool may be provided.

  The outer diameter of the cap 23 is arbitrary as long as it is smaller than the inner diameter of the screw hole 43 and the insertion hole. When the outer diameter of the cap 23 is smaller than the outer diameter of the other part of the pipe-shaped member 21, the position of the stator 20 can also be obtained by bringing the end of the pipe-shaped member 21 into contact with the cap holding part 42. Can be determined. At this time, the engagement hole 44 may be a through hole.

As shown in FIG. 2B, the tip of the cap 23 has a two-step shape, the tip of the cap 23 is engaged with the engagement hole 44, and the step is in contact with the cap holding portion 42. The position of the stator 20 may be determined. In this case, the engagement hole 44 may penetrate the cap holding part 42.
Further, as shown in FIG. 2B, the corner of the tip of the cap 23 may be chamfered or curved so that the cap 23 can be easily engaged with the engagement hole 44, thereby improving attachment.

  When attaching the stator 20, as shown in FIG. 2A, first, the stator 20 is inserted into the screw hole 43 from the cap 23 side from the outer side (outside of the stator attachment / detachment opening 82) than the screw holding portion 41. insert. Next, the cap 23 is passed through the insertion hole of the mover 30 and inserted into the engagement hole 44 of the cap holding portion 42. At the same time, the tool is engaged with the engaging portion, the stator 20 is rotated in the radial direction, and the screw portion 22 is screwed into the screw hole 43. When the tip of the cap 23 comes into contact with the inner surface of the engagement hole 44, the rotation of the stator 20 is stopped.

  Thus, the attachment of the stator 20 is completed. When the stator 20 is removed, it can be removed by rotating the stator 20 in the opposite direction, releasing the screwing of the screw portion 22 into the screw hole 43 and then pulling it out.

(2) When the outer diameter of the screw part 22 is smaller than the other part of the pipe-like member 21 The cap holding part 42 is disposed on the side closer to the stator attaching / detaching port 82 in FIG. 1, and the screw holding part 41 is disposed on the far side. Is done. The inner diameter of the screw hole 43 is smaller than the other part of the pipe-like member 21 as shown in FIG. The position of the stator 20 is determined when the boundary portion between the pipe-shaped member 21 and the screw portion 22 contacts the screw holding portion 41. The inner diameter of the engagement hole 44 is larger than the outer diameter of the other part of the pipe-shaped member 21. Further, the engagement hole 44 penetrates the cap holding part 42.

  The cap 23 is provided with an engaging portion that engages with a tool (driver, wrench, etc.) that rotates the stator 20. In FIG. 3, a slot 26 that engages with a flat-blade screwdriver is shown as an engaging portion, but the shape of the engaging portion can be any one that can maintain a firm engagement relationship with the tool to be used. For example, a hexagonal hole that engages with a hexagon wrench may be provided. Alternatively, a cross-shaped groove that engages with a Phillips screwdriver may be provided, or, for example, a star-shaped hole that engages with a star-shaped engaging tool may be provided. The outer diameter of the cap 23 is uniquely determined by the inner diameter of the engagement hole 44.

  When attaching the stator 20, first, as shown in FIG. 3, the stator 20 is first inserted into the engagement hole 44 from the screw portion 22 side from the outer side of the cap holding portion 42 (outside the stator attachment / detachment opening 82). To do. Next, the screw portion 22 is passed through the insertion hole of the mover 30, and a tool is engaged with the engaging portion to rotate the stator 20 in the radial direction so that the screw portion 22 is screwed into the screw hole 43. When the boundary portion of the pipe-like member 21 with the screw portion 22 contacts the screw holding portion 41, the rotation of the stator 20 is stopped.

  Thus, the attachment of the stator 20 is completed. When the stator 20 is removed, it can be removed by rotating the stator 20 in the opposite direction, releasing the screwing of the screw portion 22 into the screw hole 43 and then pulling it out.

  In both the structures (1) and (2), the stator 20 can be easily attached and detached from the stator attaching / detaching port 82 only by the operation of rotating the stator 20 in the radial direction.

In the above embodiment, the stator 20 is arranged in parallel with the base 2 of the radiation image reading apparatus 1. However, the stator 20 may be arranged vertically, for example, and a specific detailed structure can be changed as appropriate. .
In the above-described embodiment, the radiation image reading apparatus 1 has been described. However, the present invention is not limited to this, and it is needless to say that the present invention may be applied to a precision conveying apparatus in other OA equipment and medical equipment.

It is a schematic perspective view which shows the radiographic image reading apparatus 1 of this invention. (A), (b) is sectional drawing which shows the linear motor 10 used for the radiographic image reading apparatus 1 of FIG. It is sectional drawing which shows the linear motor 10 used for the radiographic image reading apparatus 1 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radiation image reading apparatus 5 Optical unit 10 Linear motor 20 Stator 21 Pipe-shaped member 22 Screw part 24 Magnet 30 Movable element 43 Screw hole 44 Engagement hole

Claims (10)

A plurality of magnets housed in a pipe-like member, and a stator formed by holding structures at both ends;
In a linear motor consisting of a mover through which the stator is inserted in the center,
The linear motor according to claim 1, wherein one end of the stator is formed in a screw shape.   The linear motor according to claim 1, wherein an outer diameter of the screw shape is larger than an outer diameter of another portion of the stator.   The linear motor according to claim 1, wherein an outer diameter of the screw shape is smaller than an outer diameter of another portion of the stator.   The linear motor according to any one of claims 1 to 3, wherein an engagement portion with a tool that rotates the stator in a radial direction is provided at at least one end of the stator.   The linear motor according to claim 1, wherein an outer shape of the magnet is a cylindrical shape.   The linear motor according to claim 1, wherein the magnet is a rare earth magnet. A stator holding structure for a linear motor according to any one of claims 1 to 6,
A first holding portion provided with a screw hole screwed with one end portion formed in a screw shape of the stator, and a second holding hole provided with an engagement hole engaged with the other end portion of the stator. The stator holding structure of the linear motor, characterized by comprising:   The stator holding structure for a linear motor according to claim 7, wherein an inner diameter of the screw hole is smaller than an inner diameter of the engagement hole.   The linear motor stator holding structure according to claim 7, wherein an inner diameter of the screw hole is larger than an inner diameter of the engagement hole.   In the radiographic image reading apparatus which scans a photostimulable phosphor panel with an optical unit, the linear motor according to any one of claims 1 to 6 is used as a drive source for transporting the optical unit or the photostimulable phosphor panel. A radiographic image reading apparatus characterized by comprising:

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