WO2017169908A1 - Linear motor, voice coil motor, and stage device - Google Patents

Abstract

Disclosed is a linear motor wherein a mover 10 includes a coil unit 18, and a coil holder 11 that houses and supports a part of the coil unit 18. The coil unit 18 includes a plurality of coils 15, a resin layer 16, and a film section 14. The resin layer 16 covers the coils 15. The film section 14 covers at least a part of the resin layer 16. The film section 14 has a portion in contact with the coil holder 11.

Description

Linear motor, voice coil motor, stage device

The present invention relates to a linear motor and a voice coil motor.

A linear motor is used to convert electrical energy into linear motion. For example, Patent Document 1 describes a linear motor including a stator composed of a permanent magnet and a field yoke, and a movable coil type armature having a coil unit including a plurality of coils in the movable element.

The linear motor described in Patent Document 1 is particularly equipped with a cooling unit. This cooling unit is formed of a block-like high heat conductive member, and is provided detachably with respect to a mounting plate to which an armature is attached. A plurality of heat pipes are provided inside the cooling unit, and a heat sink with fins is in contact with the heat radiating side of the heat pipe. That is, this linear motor improves the cooling performance of the armature coil by devising its arrangement using a heat pipe and a heat sink with fins.

JP 2002-238238 A

There is a method to increase the thrust of the linear motor by increasing the coil unit current in order to drive the linear motor at a higher speed. However, when the current of the coil unit is increased, the amount of generated heat increases and the temperature of the coil unit rises. When the temperature of the coil unit rises, it is also transmitted to peripheral devices by radiation, and there is a concern that the accuracy of the coil unit may be reduced by changing the temperature of these devices. Further, when the temperature of the coil unit rises, the electrical resistance of the coil unit itself increases, and the magnetic flux of the field magnet decreases due to its temperature characteristics, so that the thrust characteristics of the linear motor also deteriorate. Therefore, it is desirable to suppress the temperature rise of the coil unit in order to suppress the accuracy of the device on which the linear motor is mounted and the deterioration of the characteristics of the linear motor itself.

In order to suppress the temperature rise of the coil unit, it may be considered to attach a heat radiation fin to the coil unit. However, in this case, there is a problem that the ambient temperature of the heat dissipating fins rises and the accuracy of surrounding members is lowered. Further, in the case of air cooling, almost no effect is produced under a reduced vacuum environment. In addition, it is conceivable to provide a cooling pipe in an empty space by reducing the size of the coil. In this case, however, there is a problem that the thrust characteristics of the linear motor are reduced due to the size reduction of the coil. It is also conceivable to cover the coil unit with a jacket and circulate the refrigerant in the gap between them to recover the heat. In this case, however, the number of parts of the coil unit including the jacket increases and the number of assembly steps increases. There is a problem that productivity decreases.
Thus, the conventional linear motor technology has room for improvement from the viewpoint of suppressing the temperature rise of the coil unit while maintaining the productivity of the coil unit.
Such a problem is not limited to a linear motor, but may also occur for a voice coil motor.

One of the objects of the present invention is to provide a linear motor or a voice coil motor capable of suppressing the temperature rise of the coil unit.

In order to solve the above problems, a linear motor according to an aspect of the present invention includes a mover including a coil unit and a coil holder that accommodates and supports a part of the coil unit. The coil unit includes a plurality of coils, a resin layer that covers the plurality of coils, and a coating portion that covers at least a part of the resin layer.

According to this aspect, the heat generated in the coil unit can be recovered to the coil holder through the resin layer and the coating portion covering at least a part of the resin layer.

Another aspect of the present invention is a voice coil motor. The voice coil motor includes a coil unit and a coil holder that supports the coil unit. The coil unit includes a coil, a resin layer that covers the coil, and a coating portion that covers at least a part of the resin layer.

A stage apparatus according to another aspect of the present invention includes the linear motor described above.

According to the present invention, it is possible to provide a linear motor or a voice coil motor that can suppress the temperature rise of the coil unit.

It is a perspective view of the linear motor which concerns on 1st Embodiment. It is a side view of the linear motor which concerns on 1st Embodiment. It is a top view of the stator concerning a 1st embodiment. It is a perspective view of the needle | mover which concerns on 1st Embodiment. It is a sectional side view of the needle | mover which concerns on 1st Embodiment. It is sectional drawing of the front view of the needle | mover which concerns on 1st Embodiment. It is a schematic diagram which shows the path | route of the refrigerant | coolant of the needle | mover which concerns on 1st Embodiment. It is sectional drawing of the front view of the needle | mover which concerns on a modification. It is a top view of the stage apparatus using the linear motor which concerns on 1st Embodiment. It is a side view which shows typically the voice coil motor which concerns on 2nd Embodiment. It is a top view which shows typically the stator of the voice coil motor which concerns on 2nd Embodiment. FIG. 12 is a sectional view showing a longitudinal section along the line AA of the stator of FIG. 11. It is a top view which shows the state which remove | excluded the film | membrane part from the stator of FIG. It is a top view which shows typically the stator of the voice coil motor which concerns on a modification. FIG. 15 is a sectional view showing a longitudinal section along the line BB of the stator of FIG. 14. It is a top view which shows typically the stator of the voice coil motor which concerns on another modification. FIG. 17 is a sectional view showing a longitudinal section along the line CC of the stator in FIG. 16.

Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. In addition, in the drawings, some of the members that are not important in describing each embodiment are omitted. In addition, each embodiment does not limit the invention but is an exemplification, and all features and combinations described in each embodiment are not necessarily essential to the invention.

[First Embodiment]
FIG. 1 is a perspective view of a linear motor 2 according to the first embodiment. FIG. 2 is a side view of the linear motor 2 according to the first embodiment. The linear motor 2 includes a stator 20 and a mover 10. The stator 20 mainly includes a yoke 22, a field magnet 24, and an auxiliary pole magnet 26 that is a magnet different from the field magnet 24, and forms a field magnetic field in the magnetic gap 34. The mover 10 is provided in the magnetic gap 34 of the stator 20 so as to be movable in the movable direction. Hereinafter, description will be made based on the XYZ orthogonal coordinate system. The X-axis corresponds to the horizontal left-right direction, the Y-axis corresponds to the horizontal front-rear direction, and the Z-axis corresponds to the vertical up-down direction. The Y-axis direction and the Z-axis direction are each orthogonal to the X-axis direction. The X-axis direction may be referred to as the left direction or the right direction, the Y-axis direction may be referred to as the forward direction or the rear direction, and the Z-axis direction may be referred to as the upward direction or the downward direction. In FIG. 1, the movable direction of the mover 10 is set to the horizontal direction (X-axis direction). Such notation of the direction does not limit the use posture of the linear motor 2, and the linear motor 2 can be used in an arbitrary posture.

(stator)
FIG. 3 is a plan view of the stator 20 according to the first embodiment. The yoke 22 supports the field magnet 24 and the auxiliary pole magnet 26 and constitutes a magnetic circuit as a back yoke for the field magnet 24 and the auxiliary pole magnet 26.

The yoke 22 may be formed in, for example, a long and substantially rectangular shape. The field magnet 24 forms a field magnetic field in the magnetic gap 34. The auxiliary pole magnet 26 forms a Halbach array structure together with the field magnet 24 to reinforce the field magnetic field of the magnetic gap 34. A plurality of field magnets 24 are bonded and fixed inside the yoke 22 (on the magnetic gap 34 side) in a plurality of straight lines in the moving direction (X-axis direction) of the mover 10. The auxiliary pole magnet 26 is fixed between two adjacent field magnets 24. The field magnet 24 and the auxiliary pole magnet 26 are formed of, for example, a magnetic material containing a rare earth element by a sintering method. The field magnet 24 and the auxiliary pole magnet 26 may have a surface layer such as a plating layer. The field magnet 24 and the auxiliary pole magnet 26 are formed in a rectangular plate shape, for example. In the present invention, it is not essential to provide the supplementary magnet 26.

The field magnet 24 has a thin rectangular parallelepiped shape in the Y-axis direction, has a front surface and a back surface on which magnetic pole surfaces are respectively formed, and the back surface is fixed to the inner side surface of the yoke 22. That is, the magnetization direction 24m of the field magnet 24 is formed parallel to the Y axis. As shown in FIG. 3, magnetic poles having opposite polarities are provided in front of the two field magnets 24 facing each other across the magnetic gap 34. For this reason, these field magnets 24 generate a magnetic attractive force attracting each other. Due to this magnetic attractive force, a load in the inward direction is input to the opposing yokes 22 via the magnetic gap 34.

The auxiliary pole magnet 26 has a thin rectangular parallelepiped shape in the Y-axis direction, has a front surface and a back surface parallel to the X-axis, and the back surface is fixed to the inner side surface of the yoke 22. Magnetic pole surfaces are formed on both side surfaces of the auxiliary magnet 26, respectively. That is, the magnetization direction 26m of the auxiliary pole magnet 26 is formed parallel to the X axis.

It is desirable that the magnetic circuit of the linear motor has a configuration in which the magnetic field of the auxiliary pole magnet 26 can be concentrated on the magnetic gap 34 side in order to improve the motor characteristics while suppressing the saturation of the yoke 22. Therefore, the magnetization direction 26m of the auxiliary pole magnet 26 of the first embodiment is formed in a direction 90 ° different from the magnetization direction 22m of the field magnet 24. With this configuration, the field magnet 24 and the auxiliary magnet 26 form a Halbach array structure, and the magnetic field of the field magnet 24 can be collected on the magnetic gap 34 side.

(Movable element)
Next, the mover 10 according to the first embodiment will be described. FIG. 4 is a perspective view of the mover 10. FIG. 5 is a side sectional view of the mover 10 taken along a vertical plane along the line AA. The mover 10 mainly includes a coil unit 18 and a coil holder 11. The coil unit 18 includes a plurality of (for example, three) coils 15. The coil holder 11 accommodates and supports the upper part (end part in the Z-axis direction) of the coil unit 18.

The coil holder 11 has a rectangular parallelepiped shape elongated in the X-axis direction, and is formed of a metal material such as an aluminum alloy having excellent thermal conductivity. The coil holder 11 is provided with an accommodation recess 11 g for accommodating a part of the coil unit 18. The housing recess 11 g extends in the X-axis direction on the lower surface of the coil holder 11. The housing recess 11 g houses the upper part of the coil unit 18. A portion of the housing recess 11 g facing the coil unit 18 has a shape corresponding to the shape of the coil unit 18. In particular, the portion of the housing recess 11 g that faces the coil unit 18 has a shape along the undulation of the surface of the coil unit 18. As an example, a protrusion 11j corresponding to the recess 18j of the coil unit 18 is formed at a portion of the housing recess 11g facing the coil unit 18. In this case, the gap between the coil unit 18 and the housing recess 11g is reduced, and the heat generated in the coil unit 18 can be effectively recovered in the coil holder 11.

As shown in FIG. 5, the coil holder 11 is provided with a cooling passage that extends in the vicinity of the coil unit 18 and allows the refrigerant to pass therethrough. The cooling passage includes a plurality of (for example, two) cooling passages 11e and 11f extending in the X-axis direction. The cooling passages 11e and 11f penetrate the coil holder 11 in the X-axis direction. The cooling passages 11e and 11f may be horizontal holes drilled in the coil holder 11 or pipes embedded in the coil holder 11. The cooling passages 11e and 11f are passages for passing a cooling liquid. As shown in FIG. 5, the cooling passages 11 e and 11 f are provided in the vicinity of the coil unit 18. The range of the cooling passages 11e and 11f in the Y-axis direction has a portion that overlaps the range of the coil unit 18 in the Y-axis direction.

As shown in FIG. 4, both end surfaces of the coil holder 11 in the X-axis direction are covered with holder covers 12a and 12b, respectively. The holder cover 12a covers the left end surface of the coil holder 11, and is provided with tubular end portions 12h and 12j communicating with the cooling passages 11e and 11f. The tubular ends 12h and 12j may be connected to a radiator (not shown). The holder cover 12b covers the right end surface of the coil holder 11 and connects the cooling passages 11e and 11f. The holder cover 12b is provided with a folded passage 12g. One opening 12f of the passage 12g is connected to the cooling passage 11f, and the other opening 12e is connected to the cooling passage 11e. The refrigerant sent out from the passage 12g is sent out to the cooling passage 11f through the passage 12g.

The coil unit 18 mainly includes a plurality of coils 15, a resin layer 16, and a coating part 14. The coil unit 18 is provided at an extension end of a fixing portion 18h that is received and fixed in the receiving recess 11g of the coil holder 11, and an intermediate portion 18m that extends from the fixing portion 18h in a direction away from the coil holder 11 (Z direction). And a non-fixed portion 18d provided. The intermediate part 18m is a thin plate-like part in the Y-axis direction. The intermediate portion 18m has a substantially rectangular shape when viewed from the front and a substantially I shape when viewed from the side. The intermediate portion 18m mainly includes a first side 15p and a second side 15q, which will be described later, of the coil 15. The fixing portion 18h is a block-shaped portion that is larger in the Y-axis direction than the intermediate portion 18m and is long in the X-axis direction. The fixing portion 18h has a substantially rectangular shape when viewed from the front and a substantially V shape when viewed from the side. The fixing portion 18h may be substantially T-shaped, substantially Y-shaped or substantially I-shaped in side view. The fixing portion 18h mainly includes a third side 15h to be described later of the coil 15. The non-fixed portion 18d is a block-shaped portion that is larger in the Y-axis direction than the intermediate portion 18m and is long in the X-axis direction. The non-fixed portion 18d has a substantially rectangular shape when viewed from the front and a substantially rectangular shape or an inverted V shape when viewed from the side. The non-fixed portion 18d mainly includes a later-described fourth side 15d of the coil 15.

(coil)
FIG. 6 is a cross-sectional view of the mover 10 as viewed from the front. FIG. 6 shows a longitudinal section cut through a longitudinal plane parallel to the X-axis direction through the front side of the coil closest to the front surface among the plurality of coils 15, and a longitudinal section of a cooling passage 11f and a longitudinal section of an end passage 11d described later. It is schematically shown with the surface overlapped. Each of the plurality of coils 15 is disposed so as to partially overlap along the movable direction (X-axis direction) of the mover 10. The coil 15 is an air-core coil formed by winding a conductive wire (for example, a copper wire) whose surface is insulated a predetermined number of times. The coil 15 extends in the X-axis direction and the Z-axis direction and is thinly formed in the Y-axis direction. The coil 15 has a substantially rectangular shape when viewed from the front. The coil 15 includes a first side 15p and a second side 15q that are spaced apart in the movable direction (X-axis direction) of the mover 10, and a third side 15h and a fourth side 15d that are spaced apart in the Z-axis direction. And having. The first side 15p and the second side 15q mainly face the field magnet 24 and the auxiliary pole magnet 26 in the Y-axis direction and extend substantially linearly along the Z-axis direction. The third side 15h and the fourth side 15d extend substantially linearly along the X-axis direction. The first side 15p and the second side 15q are working sides that generate a thrust when a current flows, and the third side 15h and the fourth side 15d are non-working sides that generate substantially no thrust. As shown in FIG. 5, the third side 15h and the fourth side 15d may be bent in the Y-axis direction.

(Resin layer)
The resin layer 16 is a resin layer that covers the plurality of coils 15. The resin layer 16 is configured to support the coil 15, collect heat generated in the coil 15, and transmit it to the coating portion 14. The resin layer 16 may be a resin film formed by outsert molding so as to cover the entire plurality of coils 15. Such a resin film can be formed by, for example, pouring resin into a mold in which a plurality of coils 15 are arranged and then solidifying the resin film. As such a molding process, for example, means such as an injection mold and a transfer mold can be used. The resin layer 16 includes a first resin layer 16h, a second resin layer 16m, and a third resin layer 16d, and is integrally formed. The first resin layer 16h mainly includes the third side 15h of the coil 15 corresponding to the fixing portion 18h. The second resin layer 16m mainly includes the first side 15p and the second side 15q of the coil 15 corresponding to the intermediate portion 18m. The third resin layer 16d mainly includes the fourth side 15d of the coil 15 corresponding to the non-fixed portion 18d.

In order to efficiently recover the heat generated in the coil, the resin layer 16 is preferably formed of a material having high thermal conductivity. Therefore, the resin layer 16 of the coil unit 18 of the first embodiment is desirably formed of a material having a higher thermal conductivity than a general-purpose epoxy resin having a thermal conductivity of about 0.2 W / (m · K). More preferably, the resin layer 16 is made of a material having a thermal conductivity of 0.5 W / (m · K) or more, more preferably 1 W / (m · K) or more, and even more preferably 5 W / (m · K) or more. It is desirable to be formed. As such a material, a high thermal conductivity resin (for example, a high thermal conductivity PPS resin) can be used.

(Coating part)
The film part 14 is a film that covers at least a part of the resin layer 16. The film part 14 is configured to recover the heat of the resin layer 16 and transmit it to the coil holder 11. The film part 14 may be formed from a material having a higher thermal conductivity than the resin layer 16, for example. The film part 14 may be formed from metal materials, such as aluminum alloy and stainless steel, for example. The film part 14 may be formed from nonmetallic materials, such as a graphite sheet, for example. The film | membrane part 14 may be formed from the board | plate material and foil material which were formed from these materials. The coating portion 14 is preferably formed from a nonmagnetic material. When the film part 14 is excessively thick, it is conceivable that the magnetic air gap 34 becomes wider and the magnetic resistance increases accordingly. For this reason, as for the thickness of the membrane | film | coat part 14, 1 mm or less is desirable. More preferably, the thickness of the film part 14 is 0.2 mm or less, and more preferably 0.1 mm or less. The film part 14 of the first embodiment is formed from nonmagnetic stainless steel having a thickness of 0.03 mm.

As an example, the coating portion 14 may be formed by winding a material around the resin layer 16. As another example, the film part 14 may be formed by attaching a material pre-formed into a predetermined shape to the resin layer 16. In this case, the film part 14 may be preformed into a shape that encloses the resin layer 16. An adhesive may be interposed between the film portion 14 and the resin layer 16, and these may be bonded and fixed. This adhesive desirably has a high thermal conductivity similar to that of the resin layer 16. The film part 14 includes a first film part 14m and a second film part 14h. The first coating portion 14m is a cylindrical portion that mainly covers the second resin layer 16m corresponding to the intermediate portion 18m. The first film part 14m recovers the heat of the intermediate part 18m. The second coating portion 14h is a bowl-shaped portion that projects in the Y-axis direction from the coil holder 11 side of the first coating portion 14m. The second coating portion 14 h may be formed so as to contact the coil holder 11. The second coating part 14 h transfers heat to the coil holder 11. The second film portion 14 h may be fixed to the coil holder 11 by the fixing tool 13. In the second coating portion 14h of the first embodiment, the fixing tool 13 that is a screw passes through the second coating portion 14h and is screwed into a hole provided in the coil holder 11 to be fixed. An adhesive may be interposed between the second film part 14 h and the coil holder 11. It is desirable that the second coating portion 14h is in close contact with the coil holder 11.

(End passage)
The linear motor 2 of the first embodiment is further provided with an end passage 11d that is a cooling passage for allowing the refrigerant to pass therethrough and is a cooling passage different from the cooling passage. The end passage 11 d extends in the vicinity of the plurality of coils 15 at a position away from the coil holder 11. The end passage 11d may be a passage extending in the X-axis direction at the non-fixed portion 18d of the coil unit 18, for example. The end passage 11d may be a horizontal hole bored in the non-fixed portion 18d, or a pipe embedded in the non-fixed portion 18d. The end passage 11d is configured so that the refrigerant collects and discharges the heat in the non-fixed portion 18d by allowing the refrigerant to pass therethrough. From the viewpoint of efficiently recovering heat generated in the coil 15, the end passage 11 d is desirably provided in the vicinity of the fourth side 15 d of the coil 15. More preferably, it is desirable that the Z-axis range of the end passage 11 d at least partially overlaps the Z-axis range of the plurality of coils 15. It is not essential that the connection passages 11h and 11m are provided in the coil unit 18.

(Connection passage)
Connection passages 11h and 11m that connect the cooling passages 11e and 11f and the end passage 11d may be provided. The connection passages 11h and 11m are provided in the coil unit 18, for example. As shown in FIG. 6, the connection passages 11 h and 11 m extend in the Z-axis direction at the intermediate portion 18 m of the coil unit 18. The connection passages 11h and 11m are passages for allowing the refrigerant to pass through the cooling passages 11e and 11f and the end passage 11d. The connection passages 11h and 11m may be vertical holes formed in the intermediate portion 18m of the coil unit 18, or may be pipes embedded in the intermediate portion 18m of the coil unit 18. The connection passages 11h and 11m are configured such that the refrigerant collects and discharges the heat of the intermediate portion 18m of the coil unit 18 by allowing the refrigerant to pass therethrough.

From the viewpoint of efficiently recovering the heat of the coil, it is desirable that the connection passage extends closer to the coil. Therefore, the connection passages 11h and 11m include a portion extending between the first side 15p and the second side 15q. That is, the connection passages 11h and 11m are provided in the space between the first side 15p and the second side 15q. The third side 15h and the fourth side 15d of the coil 15 are bent outward from the center of the coil 15 in the Y-axis direction, so that the central portion of the coil 15 is vacant and can be connected with little interference with the coil 15. Passages 11h and 11m can be arranged. It is not essential that the connection passages 11h and 11m are provided in the coil unit 18.

(Refrigerant path)
FIG. 7 is a schematic diagram illustrating an example of a refrigerant path of the mover 10. The left end sides of the cooling passages 11e and 11f are connected to the tubular ends 12h and 12j of the holder cover 12a. The right end sides of the cooling passages 11e and 11f are connected through the passage 12g of the holder cover 12b. The tubular ends 12h and 12j are each connected to a radiator (not shown). The refrigerant whose temperature has been recovered by collecting heat is sent from the tubular end portion 12h to the radiator, and the refrigerant cooled by the radiator is sent to the tubular end portion 12j. The refrigerant enters the tubular end 12j as indicated by the arrow A and passes through the cooling passage 11f as indicated by the arrow B. Subsequently, the refrigerant passes through the passage 12g as indicated by an arrow C and passes through the cooling passage 11e as indicated by an arrow D. Subsequently, the refrigerant is sent out from the tubular end portion 12h to the radiator as indicated by an arrow E. As described above, the refrigerant circulates in the cooling passages 11e and 11f, whereby the heat of the coil holder 11 is recovered by the radiator and discharged.

Further, a part of the refrigerant sent to the tubular end portion 12j passes downward through the connection passage 11h as indicated by an arrow F and flows in the X-axis direction through the end passage 11d as indicated by an arrow G. As indicated by an arrow H, the refrigerant that has flowed into the end passage 11d flows upward through the connection passage 11m and reaches the cooling passage 11f. As described above, the refrigerant circulates through the connection passage 11h, the end passage 11d, and the connection passage 11m, whereby the heat of the coil unit 18 is recovered by the radiator and discharged. From the viewpoint of recovering heat more efficiently, the radiator may be provided with a pump that promotes circulation of the refrigerant. Further, as the refrigerant, for example, a liquid having a fluorine-based hydrofluoroether structure may be used. This liquid is excellent in thermal and chemical stability, has a substantially zero ozone depletion coefficient, and is easy to handle.

(Vacuum environment)
The linear motor 2 of the first embodiment may be used in a vacuum environment. The linear motor 2 can be suitably used, for example, in a vacuum environment in a decompression chamber. Here, the vacuum environment refers to an environment where the pressure is reduced from atmospheric pressure including ultra-high vacuum to low vacuum.

¡When a linear motor is used in a vacuum environment, the material constituting the resin layer of the coil unit may volatilize and generate gas. Such gassing can cause contamination of the vacuum chamber and the product being manufactured. Therefore, in the mover 10 of the first embodiment, at least a part of the resin layer 16 of the coil unit 18 is covered with the coating part 14. With this configuration, gas generation from the resin layer 16 can be suppressed.

When the linear motor is used in a vacuum environment, the heat dissipation generated by the coil due to convection is greatly reduced and the temperature rise of the coil is larger than when the linear motor is used under atmospheric pressure. Therefore, in the mover 10 of the first embodiment, the coating unit 14 is provided on the outer surface of the coil unit 18, and the coating unit 14 comes into contact with the coil holder 11, so that the heat generated in the coil unit 18 is generated by the coil holder 11. The temperature rise of the coil unit 18 is suppressed.

Next, features of the linear motor 2 according to the first embodiment configured as described above will be described.
In the linear motor 2 of the first embodiment, the coil unit 18 includes a plurality of coils 15, a resin layer 16 that covers the plurality of coils 15, and a coating portion 14 that covers at least a part of the resin layer 16. The film part 14 has a part that contacts the coil holder 11. According to this configuration, the heat generated in the coil 15 can be recovered in the coil holder 11 through the resin layer 16 and the coating portion 14.

In the linear motor 2 of the first embodiment, the coil holder 11 is provided with cooling passages 11e and 11f that extend in the vicinity of the coil unit 18 and allow the refrigerant to pass therethrough. According to this configuration, the heat of the coil holder 11 can be discharged through the cooling passages 11e and 11f.

The linear motor 2 according to the first embodiment further includes an end passage 11d that is a cooling passage for allowing the refrigerant to pass therethrough and is a cooling passage different from the cooling passages 11e and 11f. It extends in the vicinity of the plurality of coils 15 at a position away from the holder 11. According to this configuration, the end passage 11 d can recover the radiant heat in the vicinity of the plurality of coils 15.

In the linear motor 2 of the first embodiment, the coil unit 18 is provided with connection passages 11h and 11m that connect the cooling passages 11e and 11f and the end passage 11d that is another cooling passage. According to this configuration, the refrigerant can go around the connection passages 11h and 11m and the end passage 11d.

In the linear motor 2 according to the first embodiment, the coil 15 has a first side 15p and a second side 15q that are spaced apart from each other in the movable direction, and the connection passages 11h and 11m have a first side 15p and a second side. A portion extending between the sides 15q is included. According to this configuration, the connection passages 11h and 11m can efficiently recover heat in the vicinity of the first side 15p and the second side 15q.

In the linear motor 2 of the first embodiment, the coil holder 11 is provided with a housing recess 11g for housing a part of the coil unit 18, and the portion of the housing recess 11g that faces the coil unit 18 is the portion of the coil unit 18. It has a shape corresponding to the shape. According to this configuration, the gap between them becomes small, and the heat generated in the coil unit 18 can be effectively recovered in the coil holder 11.

The linear motor 2 of the first embodiment may be used in a vacuum environment. According to this structure, the gas generation to the said vacuum environment and the temperature rise of the coil unit 18 can be suppressed.

Next, the use of the linear motor 2 will be described. FIG. 9 is a plan view of the stage apparatus 100 using the linear motor 2 according to the first embodiment. This stage apparatus 100 is called an XY stage, and positions an object in the X direction and the Y direction.

The stage apparatus 100 mainly includes a Y stage 120, an X stage 130, and a surface plate 140. The Y stage 120 includes a pair of sliders 124 and a horizontal member 122 that extends horizontally between the pair of sliders 124. An X linear motor 2X that moves the X stage 130 in the X direction is provided on the horizontal member 122. The X linear motor 2 </ b> X includes a stator 20 that is fixed to the horizontal member 122 and extends in the X direction, and a mover (coil) 10 that is coupled to the lower surface of the X stage 130. Thus, by controlling the mover 10 of the X linear motor 2X, the X stage 130 is positioned in the X direction.

A pair of Y linear motors 2Y are provided at both ends of the surface plate 140. Each of the Y linear motors 2Y includes a mover 10 and a stator 20. The slider 124 is fixed to the stator 20 of the Y linear motor 2Y. The Y stage 120 is positioned in the Y direction by controlling the mover 10 of the Y linear motor 2Y.

The above is the configuration of the stage apparatus 100. The linear motor 2 according to the first embodiment can be suitably used for the X linear motor 2X or the Y linear motor 2Y of the stage apparatus 100. The stage apparatus 100 can be used for positioning a wafer or a glass substrate in an exposure apparatus, or can be used for an actuator used in a scanning electron microscope (SEM).

The description has been given based on the first embodiment of the present invention. Those skilled in the art will appreciate that these first embodiments are examples, and that various modifications and changes are possible within the scope of the claims of the present invention, and that such modifications and changes are also within the scope of the claims of the present invention. Is understood. Accordingly, the description and drawings herein are to be regarded as illustrative rather than restrictive.

Hereinafter, modified examples of the linear motor 2 according to the first embodiment will be described. In the drawings and description of the modified example, the same reference numerals are given to the same or equivalent components and members as those in the first embodiment. The description which overlaps with 1st Embodiment is abbreviate | omitted suitably, and demonstrates the structure different from 1st Embodiment mainly.

(Modification 1)
Next, the needle | mover 210 which concerns on the modification 1 is demonstrated. FIG. 8 is a front sectional view of the mover 210 corresponding to FIG. 6. The mover 210 is different from the mover 10 in the arrangement of the connection passages 11h and 11m, and the other configurations are the same. Therefore, the overlapping description is omitted and the differences are mainly described. In the mover 10, the connection passages 11 h and 11 m are disposed inside the coil unit 18, whereas in the mover 210, the connection passages 11 h and 11 m are disposed outside the coil unit 18. As shown in FIG. 8, both ends of the end passage 11d protrude from both end surfaces of the coil unit 18 in the X-axis direction. The upper end of the connection passage 11 h connected to the left protruding end of the end passage 11 d is connected to the cooling passages 11 e and 11 f outside the coil unit 18. The upper end of the connection passage 11h may be connected to the cooling passages 11e and 11f, for example, by a holder cover 12a. The upper end of the connection passage 11m connected to the right protruding end of the end passage 11d is connected to the cooling passages 11e and 11f outside the coil unit 18. The upper end of the connection passage 11m may be connected to the cooling passages 11e and 11f by a holder cover 12b, for example. According to the configuration of the first modification, since the connection passages 11h and 11m are disposed outside the coil unit 18, the coil unit 18 can be easily manufactured.

(Modification 2)
In 1st Embodiment, although the film | membrane part 14 demonstrated the example formed from the board | plate material and foil material which are formed from a predetermined material, it is not restricted to this. The film part 14 may be a film part formed by known film forming means such as a vapor deposition film, a sputtered film, and a plating film.

(Modification 3)
In 1st Embodiment, although the coil unit 18 demonstrated the example containing the three coils 15, it is not restricted to this. The coil unit may include four or more coils.

(Modification 4)
In the first embodiment, the example in which the cooling passage extends in the X-axis direction has been described, but the present invention is not limited to this. The cooling passage may include a portion extending in the Y-axis direction other than the X-axis direction, for example.

(Modification 5)
In the first embodiment, an example in which two cooling passages are provided has been described, but the present invention is not limited to this. One or three or more cooling passages may be provided.

(Modification 6)
In the first embodiment, the example in which the end passage 11d is provided inside the coil unit 18 has been described. However, the present invention is not limited to this. The end passage may be provided outside the coil unit. The end passage may be provided in the yoke 22, for example. As an example, the end passage may be provided at the bottom 28 of the yoke 22 (see FIG. 2). By providing the bottom portion 28 close to the Z-axis direction side of the non-fixed portion 18d, the heat generated in the coil unit 18 can be efficiently recovered in the end passage. Such an end passage may be a hole drilled in the yoke 22 or a pipe embedded in the yoke 22.

(Modification 7)
In the first embodiment, the example in which the end passage 11d communicates with the cooling passages 11e and 11f has been described, but the present invention is not limited thereto. The end passage may be connected to a refrigerant circulation means different from the cooling passages 11e and 11f.

[Second Embodiment]
The second embodiment of the present invention relates to a voice coil motor. FIG. 10 is a side view schematically showing a voice coil motor 300 according to the second embodiment. The voice coil motor 300 according to the second embodiment includes a stator 320 and a mover 310 provided so as to be movable along a linear or arcuate track with respect to the stator 320. The stator 320 and the mover 310 face each other in the Z-axis direction with the magnetic gap 318 interposed therebetween. Stator 320 includes a coil unit 328. The mover 310 mainly includes a field magnet 312 and a back yoke 314 provided on the opposite side of the field magnet 312 from the stator 320. A surface of the field magnet 312 facing the stator 320 is provided with a plurality of magnetic poles (for example, two poles) arranged in the moving direction of the mover 310. By energizing the coil unit 328, the coil unit 328 forms a coil magnetic flux. Due to the interaction between the coil magnetic flux and the field magnetic flux of the field magnet 312, a thrust in the Y-axis direction is generated in the field magnet 312.

The field magnet 312 extends in the X-axis direction and the Y-axis direction and is thinly formed in the Z-axis direction, and has a substantially rectangular shape or a substantially trapezoidal shape in plan view. The field magnet 312 can be formed of various magnet materials such as an NdFeB magnet material. The back yoke 314 extends in the X-axis direction and the Y-axis direction, is formed thin in the Z-axis direction, and has a substantially rectangular shape or a substantially trapezoidal shape in plan view. The back yoke 314 can be formed of a metal material having soft magnetism such as a steel plate.

FIG. 11 is a plan view schematically showing the stator 320 of the voice coil motor 300. FIG. FIG. 12 is a cross-sectional view showing a longitudinal section of the stator 320 along the line AA. FIG. 13 is a plan view showing a state in which a later-described film portion 326 is removed from the stator 320. The stator 320 mainly includes a coil unit 328 and a coil holder 322. The coil unit 328 mainly includes a coil 330, a resin layer 332, and a coating portion 326.

The coil 330 is an air-core coil formed by winding a conductive wire (for example, copper wire) whose surface is insulated a predetermined number of times. The coil 330 extends in the X-axis direction and the Y-axis direction, is formed thin in the Z-axis direction, and has a substantially oval shape in plan view. The coil 330 forms a magnetic flux directed in the Z-axis direction according to the drive current. The coil unit 328 includes one coil 330. The coil unit 328 may include a plurality of coils.

The coil holder 322 is a member for holding the coil unit 328 in a chassis (not shown). The coil holder 322 includes a base portion 322b and a frame portion 322c. The base 322b is a part fixed to the chassis. The base 322b extends in the X-axis direction and the Y-axis direction and is formed thin in the Z-axis direction, and has a substantially rectangular shape in plan view. The long side of the base 322b extends in the Y-axis direction, and the short side extends in the X-axis direction.

The frame part 322c is a frame-shaped part surrounding the coil 330, and one side is fixed to the base part 322b. The frame portion 322c is formed to be slightly larger than the outer shape of the coil 330, and a resin is interposed between the coil 330 and the frame portion 322c. The coil holder 322 can integrally form the base portion 322b and the frame portion 322c with a metal material such as aluminum. The base portion 322b and the frame portion 322c may be separately formed and combined.

The resin layer 332 is a resin layer provided so as to cover the coil 330. The resin layer 332 includes a film-shaped portion that covers both end surfaces of the coil 330 in the Z-axis direction, and a portion that is filled between the coil 330 and the frame portion 322c. The resin layer 332 is configured to support the coil 330 and collect and diffuse the heat generated in the coil 330 to make the temperature distribution uniform. The resin layer 332 can be formed, for example, by pouring resin into a mold in which the coil holder 322 and the coil 330 are set. As such a molding process, for example, a molding process such as injection molding or transfer molding can be used.

In order to efficiently recover the heat generated in the coil 330, the resin layer 332 is desirably formed of a material having high thermal conductivity. The resin layer 332 is preferably formed of a material having a higher thermal conductivity than a general-purpose epoxy resin having a thermal conductivity of about 0.2 W / (m · K). More preferably, the resin layer 332 is made of a material having a thermal conductivity of 0.5 W / (m · K) or more, more preferably 1 W / (m · K) or more, and even more preferably 5 W / (m · K) or more. It is desirable to be formed. As such a material, a high thermal conductivity resin (for example, a high thermal conductivity PPS resin) can be used. The thickness in the Z-axis direction between the coil 330 and the coating portion 326 is desirably small, and can be set to 3 mm or less, preferably 0.1 mm or less, for example.

The coating portion 326 is a coating provided so as to cover at least a part of the resin layer 332. The film part 326 extends in the X-axis direction and the Y-axis direction and has a thin sheet shape in the Z-axis direction. As an example, the film portion 326 has an oval shape that is long in the Y-axis direction in plan view. The film part 326 has a shape that substantially covers the coil 330 of the coil unit 328. The film part 326 may be formed so as to cover the coil 330 in a planar shape, and the entire edge of the film part 326 may protrude outward beyond the outer edge of the coil 330. The film portion 326 may be provided integrally when the resin layer 332 is formed on the coil 330. The film portion 326 may be provided on the surface of the resin layer 332 by a method such as adhesion after the resin layer 332 is provided on the coil 330.

As shown in FIG. 12, the film portion 326 may include a heat transfer layer 326b, an adhesive layer 326c, and a protective layer 326d. In FIG. 12, for easy understanding, the ratio of the thickness of each layer is shown as a ratio different from the actual one. The adhesive layer 326 c is a layer made of an adhesive for adhering the heat transfer layer 326 b to the resin layer 332. The adhesive desirably has a thermal conductivity equal to or higher than that of the resin layer 332. The protective layer 326d is a layer for protecting the surface side of the heat transfer layer 326b. The protective layer 326d is desirably thin as long as the surface side of the heat transfer layer 326b can be protected. The protective layer 326d can be formed using an organic material such as a resin or an inorganic material such as a metal. For the protective layer 326d, for example, a fluorine resin such as Teflon (registered trademark) or a polyimide resin film material such as Kapton (registered trademark) can be used. Note that the adhesive layer 326c and the protective layer 326d are not necessarily provided. For example, by providing the heat transfer layer 326b integrally when the resin layer 332 is provided, the heat transfer layer 326b can be fixed to the resin layer 332 without an adhesive layer. For example, when the heat transfer layer 326b is formed from aluminum or stainless steel, or when there is no physical contact with the heat transfer layer 326b, a configuration without a protective layer is also possible.

The heat transfer layer 326b may be formed of a material having a higher thermal conductivity than the resin layer 332, for example. The heat transfer layer 326b can be formed of a metal material such as an aluminum alloy or stainless steel. The heat transfer layer 326b can be formed of a nonmetallic material such as a graphite sheet. The heat transfer layer 326b may be formed of a plate material or a foil material formed of these materials. The heat transfer layer 326b may be formed of, for example, an anisotropic material having a different thermal conductivity depending on the direction, or may be formed of an isotropic material having a uniform thermal conductivity depending on the direction. The heat transfer layer 326b is preferably formed from a material that does not generate eddy current or a material that does not easily generate eddy current. From this point of view, the heat transfer layer 326b can be, for example, a thin film such as copper, silver, or gold, a foil-like sheet, or a thin sheet formed of artificial or natural graphite.

The heat transfer layer 326b is preferably formed of a nonmagnetic material. If the heat transfer layer 326b is too thick, it is conceivable that the magnetic gap becomes wider and the magnetic resistance increases accordingly. For this reason, the thickness of the heat transfer layer 326b is desirably 1 mm or less. More preferably, the thickness of the heat transfer layer 326b may be 0.2 mm or less, more preferably 0.1 mm or less. The heat transfer layer 326b of the second embodiment is made of an aluminum alloy having a thickness of 0.03 mm.

In the configuration in which the coating part 326 is not provided, the heat generated in the peripheral part of the coil 330 is recovered in the base part 322b and the frame part 322c of the coil holder 322, and thus the temperature rise in the peripheral part is suppressed. However, the heat generated in the central portion of the coil 330 is difficult to be recovered because the distance to the coil holder 322 is long, and the temperature rise in the central portion is increased. For this reason, the electric current which can be sent through the coil 330 is restrict | limited to the range in which the temperature of the center part of the coil 330 does not exceed the allowable temperature of a wire.

The voice coil motor 300 according to the second embodiment includes a coil unit 328 and a coil holder 322 that supports the coil unit 328. The coil unit 328 includes a coil 330, a resin layer 332 that covers the coil 330, and a coating portion 326 that covers at least a part of the resin layer 332. According to this configuration, by providing the coating portion 326, the heat of the resin layer 332 can be recovered on the surface to facilitate its diffusion, and the temperature distribution of the resin layer 332 can be made uniform. In addition, by providing the coating portion 326, the heat of the resin layer 332 can be easily transmitted to the coil holder 322. By these actions, the temperature of the high temperature portion of the coil 330 is lowered, and the current that can be passed through the coil 330 can be increased.

In the voice coil motor 300 according to the second embodiment, the coating portion 326 includes a heat transfer layer 326b formed of a material having a higher thermal conductivity than the resin layer 332, and protection for protecting the surface of the heat transfer layer 326b. Layer 326d. According to this configuration, the temperature distribution is further uniformed by forming the heat transfer layer 326b from a material having high thermal conductivity. By providing the protective layer 326d, even when the heat transfer layer 326b is formed from a soft material such as graphite, it is possible to suppress scratching and to suppress a decrease in the thermal diffusion effect due to the scratch.

The description has been given based on the second embodiment of the present invention. Hereinafter, modified examples of the voice coil motor 300 according to the second embodiment will be described. In the drawings and description of the modified example, the same or equivalent components and members as those in the second embodiment are denoted by the same reference numerals. The description overlapping with the second embodiment will be omitted as appropriate, and the configuration different from the second embodiment will be described mainly.

(Modification 1)
In 2nd Embodiment, although the film | membrane part 326 demonstrated the example which is not contacting the coil holder 322, it is not restricted to this. For example, the film part 326 may be provided so as to contact the coil holder 322. FIG. 14 is a plan view schematically showing the stator 340 of the voice coil motor 302 according to the second modification. FIG. 15 is a cross-sectional view showing a vertical cross section of the stator 340 along the line BB. The stator 340 according to Modification 1 is different from the stator 320 according to the second embodiment in the planar shape of the coating portion 346, and the other configurations are the same. Therefore, the overlapping description will be omitted and the coating portion 346 will be described. As shown in FIG. 14, the coating portion 346 has a portion 346 b that contacts the frame portion 322 c of the coil holder 322. The film part 346 has a shape that covers at least a part of the frame part 322 c beyond the outer edge of the resin layer 332 in plan view. An adhesive may be provided between the portion 346b and the frame portion 322c. The film part 346 may include a part that contacts the base part 322b in addition to the frame part 322c.

In the voice coil motor 302 according to the first modification, the film portion 346 has a portion 346 b that contacts the coil holder 322. According to this configuration, the heat recovered from the resin layer 332 by the film portion 346 can be radiated to the coil holder 322 by the portion 346b. By dissipating heat to the coil holder 322, the temperature of the film part 346 can be lowered. Therefore, heat dissipation of the coil 330 can be facilitated, and the current that can flow through the coil 330 can be increased.

(Modification 2)
In 2nd Embodiment, although the film | membrane part 326 demonstrated the example provided in the surface layer of the coil 330, it is not restricted to this. For example, when a plurality of coils are stacked in the Z-axis direction, the coating portion may be provided on the surface layer of the coil, and a sheet having high heat conductivity may be provided between the coils of each layer. FIG. 16 is a plan view schematically showing the stator 350 of the voice coil motor 304 according to the second modification. FIG. 17 is a cross-sectional view showing a vertical cross section of the stator 350 along the line CC. The stator 350 according to the modified example 2 is different from the stator 320 according to the second embodiment in that a multilayer coil 360 and a heat transfer unit 356 provided between the layers of the coil 360 are provided. The configuration of is the same. Therefore, the description which overlaps is abbreviate | omitted and the coil 360 and the heat-transfer part 356 are demonstrated. As shown in FIG. 16, the stator 350 according to Modification 2 is the same as the stator 320 according to the second embodiment in a planar shape.

The coil unit 358 of Modification 2 includes a multilayer coil 360 instead of the coil 330 of the second embodiment. The coil 360 includes a plurality of thin coils 360b stacked in the Z-axis direction. In the example of FIG. 17, the coil 360 includes two thin coils 360 b stacked in the Z-axis direction. The thin coil 360b has a thickness dimension in the Z-axis direction that is substantially half that of the coil 330 of the second embodiment. For other configurations and characteristics of the thin coil 360b, the configuration and characteristics of the coil 330 described above can be referred to.

The heat transfer section 356 is provided between the two layers of thin coils 360b. The heat transfer part 356 extends in the X-axis direction and the Y-axis direction and has a thin sheet shape in the Z-axis direction. The heat transfer part 356 has a planar shape substantially equal to the film part 326. For the configuration and characteristics of the heat transfer section 356, the configuration and characteristics of the heat transfer layer 326b described above can be referred to.

In the voice coil motor 304 according to the second modification, the coil 360 includes a plurality of laminated thin coils 360b, and is formed of a material having higher thermal conductivity than the resin layer 332 between the plurality of thin coils 360b. A heat transfer section 356 is provided. According to this configuration, by providing the heat transfer part 356, the heat of the resin layer 332 can be recovered not only at the surface part but also between the layers to facilitate its diffusion, and the temperature distribution can be made more uniform. By this action, the temperature of the high temperature portion is lowered between the layers of the coil 360, and the current that can be passed through the coil 360 can be further increased.

(Other variations)
In 2nd Embodiment, although each membrane | film | coat part 326 demonstrated the example containing 1 layer of heat-transfer layers 326b, it is not restricted to this. The film part 326 may include a plurality of heat transfer layers.
In 2nd Embodiment, although the film | membrane part 326 demonstrated the example provided in both surfaces of the Z-axis direction of the resin layer 332, it is not restricted to this. The film part 326 may be provided only on one surface of the resin layer 332.
In the second embodiment, the example in which the respective film portions 326 are integrated has been described. However, the present invention is not limited to this. The film part 326 may include a plurality of parts divided into two or more.
These modified examples have the same operations and effects as those of the second embodiment.

In the drawings used for the description, in order to clarify the relationship between the members, the cross sections of some of the members are hatched, but the hatching does not limit the materials and materials of these members.

2. Linear motor, 10. Movable element, 11. Coil holder, 11d ... End passage, 11e ... Cooling passage, 11f ... Cooling passage, 11g ... Containing recess, 11h ... Connection passage, 11m・ ・ Connection passage, 14 ・ ・ Coating part, 15 ・ Coil, 15p ・ ・ First side, 15q ・ ・ Second side, 16 ・ ・ Resin layer, 18 ・ ・ Coil unit, 20 ・ ・ Stator, 24 ・・ Field magnet, 26 ・ ・ Supplementary magnet, 34 ・ ・ Magnetic air gap, 100 ・ ・ Stage device, 300 ・ ・ Voice coil motor, 310 ・ ・ Motor, 312 ・ ・ Field magnet, 320 ・ ・ Stator 322 ·· Coil holder 326 ·· Coating part · 326b · · Heat transfer layer · 328 · · Coil unit · 330 · Coil · 332 · · Resin layer · 360b · · · Shape coil.

The present invention can be used for a linear motor or a voice coil motor.

Claims (13)

1. A mover including a coil unit and a coil holder that accommodates and supports a part of the coil unit;
   The coil unit is
   A plurality of coils;
   A resin layer covering the plurality of coils;
   A coating covering at least part of the resin layer;
   A linear motor comprising:
2. The linear motor according to claim 1, wherein the coating portion has a portion that contacts the coil holder.
3. The linear motor according to claim 1 or 2, wherein the coil holder is provided with a cooling passage extending in the vicinity of the coil unit and allowing the refrigerant to pass therethrough.
4. A cooling passage for allowing the refrigerant to pass therethrough, further comprising a cooling passage different from the cooling passage;
   The linear motor according to claim 3, wherein the another cooling passage extends in the vicinity of the plurality of coils at a position away from the coil holder.
5. The linear motor according to claim 4, wherein the coil unit is provided with a connection passage that communicates the cooling passage with the another cooling passage.
6. The coil has a first side and a second side that are spaced apart in the moving direction of the mover,
   The linear motor according to claim 5, wherein the connection passage includes a portion extending between the first side and the second side.
7. The coil holder is provided with an accommodating recess for accommodating a part of the coil unit,
   The linear motor according to claim 1, wherein a portion of the housing recess facing the coil unit has a shape corresponding to the shape of the coil unit.
8. A linear motor according to any one of claims 1 to 7,
   A linear motor characterized by being used in a vacuum environment.
9. A stage apparatus comprising the linear motor according to any one of claims 1 to 8.
10. A coil unit;
    A coil holder for supporting the coil unit;
    With
    The coil unit is
    Coils,
    A resin layer covering the coil;
    A coating covering at least part of the resin layer;
    A voice coil motor comprising:
11. The voice coil motor according to claim 10, wherein the coating portion has a portion that contacts the coil holder.
12. The said coating | coated part contains the heat-transfer layer formed with the material whose heat conductivity is higher than the said resin layer, and the protective layer which protects the surface of the said heat-transfer layer, The Claim 10 or 11 characterized by the above-mentioned. The voice coil motor described.
13. The coil includes a plurality of laminated thin coils,
    The voice coil motor according to any one of claims 10 to 12, wherein a heat transfer portion formed of a material having a higher thermal conductivity than the resin layer is provided between the plurality of thin coils.

Images