JP2001275334A - Coil unit for linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable positioning of a coil in higher accuracy than that of a conventional coil by reducing the influence of heating of the coil to a machine on the opposite side and a circumferential atmosphere. SOLUTION: A coil unit 32 comprises a shell 4, containing the coil 40 therein and cooling the coil 40 by passing a refrigerant. The unit 32 also comprises an outside cover 64 installed therein, to contain a shell 44 therein and to enable cooling of the shell 44 by passing the refrigerant to a gap 42B. In this case, an outside first main channel 70 is formed near one lateral edge 44A of the shell in the cover 64, to enable introduction of the refrigerant and a discharge of the refrigerant to an outer surface 44C of the shell 44. Furthermore, an outside second main channel 76 is formed near the other lateral edge 44B of the shell 44 in the cover 64, to receive the refrigerant flowing along this outer surface 44C and to enable supplying of the refrigerant into the shell 44. An discharge tube for enabling an external discharge of the refrigerant flowing along the surface of the coil 40 to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor having a coil arranged opposite to a magnet in a linear motor, and a shell for accommodating the coil therein and cooling the coil by passing a coolant through a gap between itself and the shell. The present invention relates to a coil unit for a motor, and more particularly to a technique for cooling a coil with a refrigerant.

[0002]

2. Description of the Related Art Conventionally, for example, in an exposure apparatus or a high-precision processing machine for manufacturing a semiconductor, it is required to accurately and quickly position an object (for example, a wafer or a workpiece to be exposed). I have. As the precision positioning device used at this time, a device that converts the rotation of a rotary motor into a linear motion by a ball screw or the like, a linear motion motor (a so-called linear motor), and the like are widely used.

[0003] Among them, the linear motor has the advantages that the structure is simple, the number of parts is small, and that the linear motion can be directly used, and the object can be positioned quickly. In addition, since the frictional resistance at the time of driving is small, the operation accuracy can be improved. For these reasons, linear motors
It is becoming the mainstream as a linear drive device in any field where precise positioning is required, and is widely used, for example, in a manufacturing process of a liquid crystal display device.

This linear motor generally comprises a magnetic pole unit having a magnet and a coil unit having a coil. One of the magnetic pole unit and the coil unit is connected to a predetermined base and functions as a stator, and the other is connected to a moving table or the like and functions as a mover. A certain gap is provided between the magnetic pole unit and the coil unit so as not to contact each other,
It relatively moves linearly with the gap maintained.

[0005] Incidentally, the coil provided in the above-mentioned coil unit generates heat when an electric current is supplied. This heat is transmitted to the entire coil unit and further to a base, a moving table, and the like connected to the coil unit. As a result, the following two problems occur.

(1) The heat of the coil causes the coil unit itself and the other machine connected to the coil unit to thermally expand, causing an error in the positioning accuracy. Specifically, if the mating machine connected to the coil unit is, for example, a low-thermal-expansion material having a length of 100 mm (coefficient of thermal expansion: 1 × 10 −6), a thermal deformation of 100 nm by a temperature rise of 1 ° C. Occurs. Therefore, when positioning accuracy on the order of nanometers is required, the requirement cannot be sufficiently satisfied due to the thermal expansion.

(2) A laser interferometer or the like for measuring the motion of the linear motor is installed near the linear motor. When the surrounding atmosphere is heated by the coil unit and “fluctuations” occur, the optical path of the laser light is affected, and a measurement error occurs.

Here, as a technique for solving the problem (1), there is known a technique of flowing a refrigerant between a coil unit and a mounting surface of a counterpart machine in a coil unit to prevent heat from being transmitted from the coil. Have been. However, this technique cannot suppress the temperature rise of the atmosphere around the coil unit, and as a result, the problem (2) has not been solved.

To solve both of the problems (1) and (2), a coil unit 10 as shown in FIGS. 10 and 11 has been proposed. The coil unit 10 is used for the linear motor 1 and is disposed to face the magnet 3 of the magnet unit 2.

More specifically, the coil unit 10 is a flat plate-shaped coil 1 which is disposed to face the magnet 3 and is long in the traveling direction X.
2 and a shell 14 for accommodating the coil 12 therein and cooling the coil 12 by passing a coolant through a gap 13 between the coil 12 and itself. On the other hand, the magnet unit 2 includes a base 4 having a U-shaped cross section, and the magnets 3 are mounted on opposed inner walls 4 </ b> A in the base 4.

Outside the one edge 14A of the shell 14 in the width direction Y, a mounting surface 16 for a mating machine is formed. One end of the mounting surface 16 in the longitudinal direction X is Supply hole 18 for supplying refrigerant to gap 13
Is formed at the other end, and a discharge hole 20 for discharging the refrigerant is formed at the other end.
Are formed. When the coil unit 10 is connected to the “fixed side” counterpart machine via the mounting surface 16,
The coil unit 10 serves as a stator, and the magnet unit 2 serves as a mover. Conversely, when the coil unit 10 is connected to a “moving side” partner machine, the coil unit 10 becomes a mover and the magnet unit 2 becomes a stator.

The refrigerant supplied from the supply hole 18 diffuses into the gap 13 between the coil 12 and the shell 14, and transfers heat to and from the coil 12. Therefore, the coil 12 that generates heat by the electric current is cooled, and the refrigerant is heated. Since the heated refrigerant is discharged from the discharge holes 20, heat is not accumulated inside the coil unit 10, and radiation to the surrounding atmosphere is reduced. Therefore, the linear motor 1 can reduce the influence of the heat generated by the coil 12 on the outside, and can perform more accurate positioning.

[0013]

However, even in such a coil unit 10, it cannot be said that a sufficient cooling effect is always obtained. FIG. 12 schematically shows the state of diffusion of the refrigerant in the shell 14.
The refrigerant flows in parallel while gradually spreading as A, B, C,..., And is finally discharged from the discharge holes 20 while converging to F, G, H. Since the refrigerant is heated as it moves downstream, the temperature rises so as to substantially match the order of A, B, C... E, G, and H.

As a result, the temperature of the refrigerant in the vicinity of the downstream side (E, G, H) is significantly higher than that in the upstream side. 14 has a problem that heat is transmitted to the outside and radiated to the outside. Further, heat is transferred to the mounting surface 16 via the refrigerant in the high temperature state on the downstream side, which causes thermal expansion on the partner machine side.

Moreover, this characteristic is inevitably generated even if the pressure (supply pressure) of the refrigerant and the size of the gap are designed to be relatively good. Also, if the design is not good,
This is because a part where the refrigerant hardly flows is likely to occur, and the problem may become more remarkable.

In order to solve these problems, it is necessary to increase the flow rate of the refrigerant to increase the cooling efficiency. However, if the gap 13 is increased to increase the flow rate, the distance between the magnets 3 on the magnet unit 2 side is reduced. There is a problem that S (see FIG. 1) is widened, the magnetic flux density is reduced, and the driving force of the linear motor 1 is reduced. When the flow rate of the refrigerant is increased, the shell 1
It is necessary to increase the wall thickness of the linear motor 1 to increase the pressure resistance, and this increase in wall thickness also affected the reduction in the driving force (thrust) of the linear motor 1.

On the other hand, with the recent sophistication of the manufacturing process, there is an increasing demand for suppressing the temperature rise of the linear motor at a higher level. However, in a situation where certain restrictions are imposed on the thickness of the shell 14, the size of the gap 13, and the like, the coil 1 in the coil unit 10
At present, there is a limit in the cooling capacity of No. 2 and the above requirements cannot be satisfied.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems associated with the non-uniform cooling of a coil by a refrigerant as described above and the problem of insufficient cooling capacity. It is an object of the present invention to drastically reduce a temperature rise of a coil unit as compared with the related art.

[0019]

According to the present invention, there is provided a coil arranged opposite to a magnet of a linear motor, and the coil is accommodated in the gap with a predetermined gap, and the coil can be cooled by passing a coolant through the gap. And an outer cover capable of accommodating the shell with a predetermined gap therebetween and cooling the shell through a coolant through the gap, and a shell in the outer cover. An outer first main flow path formed in the longitudinal direction near one end in the width direction of the shell to introduce a refrigerant supplied from the outside into itself, and to guide the refrigerant to the outer surface of the shell in the width direction; It is formed in the outer cover in the vicinity of the other end in the width direction of the shell in the longitudinal direction so as to extend in the longitudinal direction, and receives the refrigerant flowing in the width direction on the outer surface of the shell through the outer first main flow path. By the provided outer second main channel can be supplied into the shell, and a discharge pipe can be discharged outside the refrigerant flowing the coil surface of the shell is intended to achieve the above object.

In this coil unit, a double cooling structure is employed by further disposing an outer cover around the shell. Further, the refrigerant (in a low temperature state) is first guided in the longitudinal direction of the coil by the outer first main flow path, and the gap between the shell and the outer cover is formed in the width direction (from one end to the other end) through the outer first main flow path. (Toward the side) the refrigerant flows. This refrigerant is supplied to the inside of the shell via the outer second main flow path, flows across the coil surface in the width direction (from the other end to one end), and is discharged from the discharge pipe (at the highest temperature). Is done.

Therefore, in addition to achieving uniform cooling in the longitudinal direction, the structure in which the coil surface and the outer surface of the shell are cooled by a so-called counterflow also achieves uniformity in the width direction, and thus the entire coil unit is achieved. The temperature tends to be uniform over a wide temperature range, and the cooling efficiency has been greatly increased as compared with the conventional case. As a result, a local temperature rise in the surrounding atmosphere is prevented.

Further, the refrigerant having the lowest temperature supplied into the outer cover covers the refrigerant having the highest temperature immediately before being discharged from the shell. Further, in the vicinity of the middle in the width direction, the moderately low-temperature refrigerant flowing in the outer cover covers the moderately high-temperature refrigerant in the shell (by cooling the coil). In this way, the presence of the refrigerant in the outer cover significantly reduces the heat transfer of the coil from the inside to the outside, so that the temperature rise of the coil unit can be significantly reduced as compared with the related art.

[0023] In the above invention, the refrigerant is formed in the shell so as to extend in the longitudinal direction on the outer second main flow path side, and the refrigerant supplied from the outer second main flow path is introduced into the shell itself, and the refrigerant is also discharged. An inner main flow path that can be led out in the width direction may be provided on the surface of the coil in the shell.

According to this structure, even if the flow of the refrigerant becomes uneven (disturbed) due to the flow to the outer second main flow path, the refrigerant is again introduced in the longitudinal direction by the inner main flow path. After that, the coil is guided to the coil surface, so that the coil can be cooled uniformly.

[0025] In the above invention, further, the refrigerant is formed so as to extend in the longitudinal direction on the outer first main flow path side in the shell, and receives the refrigerant flowing in the width direction on the coil surface in the shell.
An internal second main flow path capable of discharging the refrigerant from the discharge pipe may be provided.

The refrigerant which has become high temperature by cooling the coil must be discharged to the outside as soon as possible to suppress the influence of heat on the surroundings. Therefore, according to this structure,
Since the refrigerant in the high-temperature state is quickly discharged to the inner second main flow path and does not stay around the coil, the local high-temperature state on the coil is prevented.

Furthermore, the second inner main flow path in the longitudinal direction into which the (high temperature) refrigerant is introduced can be covered by the first outer main flow path in the longitudinal direction into which the coldest refrigerant is introduced. Heat transfer to the surrounding atmosphere and the machine mounting surface is suppressed. As is clear from the above description, the machine mounting surface for mounting this coil unit to the other machine is
The outer first main channel side on the outer periphery of the outer cover is preferable. This is because heat transfer from the coil is blocked by the outer first main flow path.

Further, in the above invention, a supply hole capable of supplying a coolant to the outer first main flow path is formed near one longitudinal end of the outer cover, and the other end of the outer second main flow path in the longitudinal direction is formed. In the vicinity, a communication hole capable of supplying the refrigerant guided therein to the inside of the shell is formed, and a discharge pipe capable of discharging the refrigerant in the shell is disposed in a position corresponding to the vicinity of the supply hole in the shell. Is preferred.

In this case, the refrigerant moves in the order of the supply hole, the communication hole, and the discharge pipe. Therefore, when viewed as a whole, the refrigerant is supplied from the supply hole and moves on the diagonal line of the coil unit. It becomes a cooling structure that returns to and is discharged from the discharge pipe. Therefore, a more uniform cooling effect can be obtained over the entire coil, and the temperature rise of the surrounding atmosphere can be suppressed at a higher level. In addition, since the supply side and the discharge side are close to each other, external piping design becomes easy.

Further, it is preferable to dispose the discharge pipe so as to penetrate the vicinity of the downstream side of the supply hole in the outer first main flow path, so that the discharge pipe through which the refrigerant in the highest temperature state passes is provided. Since the outer peripheral surface is cooled by the refrigerant flowing through the outer first main flow path, the coil is formed while suppressing the local temperature rise of the coil unit near the discharge pipe, that is, in a state where only the refrigerant in the discharge pipe is warmed. Heat can be recovered. Note that “near the downstream side of the supply hole” is substantially synonymous with being located inside the supply hole in the longitudinal direction and near the supply hole.

The means for guiding the refrigerant to the outer surface of the shell in the width direction by means of the outer first main flow path in all of the above-mentioned inventions includes, for example, a plurality of branch flow paths extending longitudinally to the outer first main flow path. Preferably, the coolant is formed at predetermined intervals in the direction, and the refrigerant introduced into the outer first main flow path is branched by each of the plurality of branch flow paths so as to be able to be led out to the outer surface of the shell in the width direction. Note that the number, shape, length, and the like of the branch flow paths are not limited at all, and the point is that the branch flow path may be any as long as the refrigerant can be guided in the width direction.

Further, at the downstream end of the branch flow path, a longitudinal sub-flow path capable of temporarily storing the refrigerant derived from the branch flow path is formed, and the refrigerant is supplied to the shell through the sub-flow path. It is preferable to be able to be led out to the outer surface. According to this structure,
Refrigerant derived from each branch flow path is diffused in the longitudinal direction by the sub flow path, and pressure and flow rate are led out to the outer surface of the shell while being averaged in the longitudinal direction. Uniformity can be improved. Further, since the pressure of the refrigerant in the first main channel is diffused in the longitudinal direction and flows in the width direction by the branch channel 1 or the sub channel, the thickness of the outer cover and the shell can be reduced. Even with the double cooling structure, the coil unit can be configured to be relatively compact.

By the way, the above-mentioned idea is mainly intended to suppress the thermal effect of the coil unit on the surrounding atmosphere and the partner machine. It will be possible to use it with more improved "heat dissipation".

Specifically, the coil includes a coil disposed opposite to the magnet of the linear motor, and a shell capable of accommodating the coil therein with a predetermined gap therebetween and cooling the coil by passing a coolant through the gap. In a coil unit used for a linear motor, an outer cover capable of accommodating a shell therein with a predetermined gap therebetween and cooling the shell through a refrigerant between the shell and the outer cover is provided near a first end in the width direction of the coil in the shell. A first guide path which is formed to extend in the direction, and which can introduce a refrigerant supplied from the outside into itself and guide the refrigerant to the surface of the coil in the width direction, and near the other end in the width direction of the coil in the shell The first is formed to extend in the longitudinal direction, the first
A second guide path capable of receiving the refrigerant flowing in the width direction on the surface of the coil via the guide path and supplying the refrigerant to a gap between the shell and the outer cover, and supplying the refrigerant flowing through the outer surface of the shell to the outside. And a discharge hole that can be discharged to the outside.

In the present invention, the flow of the refrigerant having the structure described above (upstream and downstream) is considered in reverse.

With this configuration, the refrigerant in the low temperature state first cools the coil surface, and then flows through the gap between the shell and the outer cover, thereby releasing the heat of the refrigerant to the outside. Therefore, since the coil can be actively cooled, it is particularly suitable for a large-capacity linear motor when it is necessary to minimize the temperature rise of the coil itself (rather than suppressing the temperature rise of the surrounding atmosphere). I have. It should be noted that the more detailed structure may be applied to the above-described structure in the opposite manner.

[0037]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 and 2 show a coil unit 32 used in the linear motor 30 according to the first embodiment.

The coil unit 32 includes a magnet unit 34
And a flat plate-shaped coil 40 long in the traveling direction X (see FIG. 2) opposed to the magnets 36, 36. The coil 40 is accommodated in the gap 40 with a predetermined gap 42 therebetween. Shell 44 capable of cooling coil 40
And an outer cover 64 capable of accommodating the shell 44 with a predetermined gap 42B therein and cooling the shell 44 by passing a coolant through the gap 42B. The magnet unit 34 has a base 38 having a U-shaped cross section.
The base 38 has a structure in which the magnets 36 are attached to the inner wall 38A.

The flat coil 40 has an I-shaped (saddle-shaped) cross section perpendicular to the traveling direction X, and more specifically, is constituted by combining a plurality of coil pieces 46 shown in FIG. Is done. The coil piece 46 is formed by winding a copper wire in a ring shape.
6A and bent portions 46B formed at both ends of the straight portion 46A. Therefore, as shown in FIG. 4, if the plurality of coil pieces 46 are alternately combined so that the linear portions 46A overlap, and the U layer, the V layer, the W layer... The above-mentioned coil-shaped coil 40 is formed. In this state, the coils 40 are not connected to each other and are disassembled. Therefore, as shown in FIG. 2, the coil 40 is formed by a resin G together with a longitudinal coil holder 48 disposed on the one end 40A side in the width direction Y. It is integrally molded.

The shell 44 is a member for accommodating the coil 40 therein, and includes a coil holder 48 and a stainless steel plate 50 connected to the coil holder 48.
And. The plate 50 is bent so as to follow the I-shaped cross section of the coil 40, and the coil 40
The predetermined gap 42 is formed in the linear portion 46A of the coil 40 in a state in which is accommodated.

The outer cover 64 is a member for accommodating the shell 44 inside. The outer cover 64 is attached to the outside of the coil holder 48 in the width direction Y and is long in the traveling direction X. An outer plate 68 of
It is comprised including. The outer plate 68 includes the shell 44
Of the coil 40 (the straight portion 4 of the coil 40).
A predetermined gap 42B is formed (at a position corresponding to 6A).

Next, the cooling structure of the coil 40 in the coil unit 32 will be described in detail with reference to FIG. 1 and FIGS.

As shown in FIGS. 5 and 6, near the one end 44A in the width direction of the shell 44 in the outer cover 64, the first outer side extending in the longitudinal direction (same as the traveling direction) X is provided.
A main channel 70 is formed. This outer first main flow path 70
In the vicinity of one end 70A in the longitudinal direction, a supply hole 72 capable of supplying a coolant to the outer first main flow path 70 is formed.
The refrigerant supplied from the supply hole 72 is supplied to the outer first main flow path 7.
0 guides in the longitudinal direction X.

A plurality of branch channels 74 are formed in the outer first main channel 70 at predetermined intervals in the longitudinal direction X. The refrigerant introduced into the outer first main flow path 70 is branched by the branch flow path 74, and flows in the width direction Y along the outer surface (gap 42B) of the shell 44.

An outer second main channel 76 extending in the longitudinal direction X is formed in the outer cover 64 near the other end 44B in the width direction of the shell 44. The outer second main flow path 76 receives the refrigerant flowing in the width direction Y through the outer surface 44 </ b> C (the gap 42 </ b> B) of the shell 44 via the outer first main flow path 70 and the branch flow path 74. 44. In addition, this outer second
The main flow path 76 is formed by expanding the gap between the plate 50 and the outer plate 68 (than the gap 42B near the linear portion 40A of the coil 40).

At the downstream end 74A (see FIG. 1) of the branch flow path 74, there is formed a sub-flow path 78 in the longitudinal direction X which can temporarily store the refrigerant derived therefrom. This sub flow path 7
Numeral 8 stores the refrigerant and guides the refrigerant to the gap 42B, and has a so-called buffer function. The sub flow path 78 is formed by expanding a gap between the plate 50 and the outer plate 68 more than the gap 42B.

The outer first main flow path 70 and the branch flow path 74 are formed with grooves on the inner wall of the outer lid 66 by cutting or the like.
What is necessary is just to comprise this outer cover 66 with the said groove | channel attached to the coil holder 48.

Next, the cooling structure inside the shell 44 will be described.

As shown in FIG. 5, inside the shell 44, an inner main flow path 56 extending in the longitudinal direction X is formed on the outer second main flow path 76 side. That is, the outer second main flow path 76 and the inner main flow path 56 are arranged in parallel. The other end 56 of the outer second main channel 76 and the inner main channel 56 in the longitudinal direction X
B (that is, a side opposite to the supply hole 72 in the longitudinal direction X) is formed with a communication hole 78 that connects these, and the refrigerant guided through the outer second main flow path 76 through the communication hole 78 is formed. It is supplied to the inner main channel 56. The inner main flow path 56 is formed by forming a groove in a flow path forming member 57 in the longitudinal direction X disposed in the shell 44.

A plurality of inner branch passages 56A are formed in the inner main passage 56 at predetermined intervals in the longitudinal direction X, and the refrigerant guided in the inner main passage 56 in the longitudinal direction X is supplied to the inner branch passages 56A. On the surface of the coil 40 via the flow path 56A (the gap 4
2) It is derived in the width direction Y. Specifically, the branch flow paths 56A are formed in three directions at predetermined intervals (see FIG. 1), and the refrigerant derived therefrom flows toward the gap 42 side.

Outer first main flow path 70 in shell 44
On the side, as shown in FIG. 7, an inner second main flow path 52 for receiving the refrigerant flowing in the width direction Y on the surface of the coil 40 is formed. Micropores 54 are formed in the inner second main flow path 52 at predetermined intervals in the longitudinal direction X (see FIG. 1).
The refrigerant flowing on the surface of the coil 40 flows into the inner second main flow channel 52 through the plurality of small holes 54. Further, a discharge pipe 55 capable of discharging the refrigerant collected by the inner second main flow path 52 is formed on one end 52A side of the inner second main flow path 52 in the longitudinal direction X. More specifically, the discharge pipe 55 penetrates the vicinity of the downstream side of the supply hole 72 in the outer first main flow path 70 and opens to the outer lid 66 side. That is, the outer first main flow path 70 surrounds the periphery of the discharge pipe 55 (see FIG. 6).

Incidentally, the inner second main flow path 52 and the fine holes 54 may be formed by cutting or the like in the coil holder 48 before the coil 40 is integrally molded.

Next, the operation of the coil unit 32 will be described.

The refrigerant supplied from the supply hole 72 is guided in the longitudinal direction X by the outer first main flow path 70. When the pressure in the outer first main flow path 70 increases, the refrigerant flows into the branch flow path 74.
Flows out to the sub flow path 78 via the Since the amount of the refrigerant introduced from each branch channel 74 into the sub-channel 78 has already been considerably uniformed in the longitudinal direction X by the function of the outer first main channel 70, the pressure of the refrigerant in the sub-channel 78 is It is made more uniform in the longitudinal direction X. Then, the refrigerant in the sub flow path 78 flows into the gap 42B in the width direction Y.

The coolant that has cooled the outer surface 44C of the shell 44 through the gap 42B flows into the outer second main flow path 76 and is guided in the longitudinal direction X. This refrigerant is supplied from the communication hole 78 to the inner main flow path 56, and is supplied to the outer second main flow path 7.
6 is guided in a direction opposite to the guiding direction. When the pressure of the refrigerant in the inner main flow path 56 increases, the refrigerant flows out of the inner branch flow path 56A and fills the inside of the shell 44. The refrigerant that has flown along the width direction Y and cooled the coil 40 flows into the inner second main flow path 52 through the fine holes 54. The refrigerant flowing into the inner second main flow path 52 is guided in the longitudinal direction X and discharged from the discharge pipe 55.

The coil unit 32 has a double structure in which the coil 40 is covered by the shell 44 and the outer cover 64. Further, the refrigerant is guided (diffused) in the longitudinal direction X by the outer first main flow path 70 and the inner main flow path 56, and thereafter flows out in the width direction Y.
Accordingly, the width direction Y in each of the gaps 42 and 42B is relatively large.
Is formed.

By the diffusion of the refrigerant in the longitudinal direction X and the counterflow in the width direction Y, uniform cooling in both the longitudinal direction X and the width direction Y can be achieved.
2 can be made uniform in temperature. As a result, even if the flow rate of the refrigerant is not increased, the cooling efficiency can be greatly increased as compared with the conventional case.

For example, according to the analysis results by the present inventor, if the heating value of the coil is 200 (W) and the flow rate of the refrigerant is 2 (l / min), the outer surface of the conventional coil unit is While the temperature rises by about 2.5 ° C., the coil unit 32 of the first embodiment is suppressed to a temperature rise of about 0.45 ° C. Although the above analysis results differ depending on the material of the shell and the type of the refrigerant, extremely excellent results can be obtained in any case.

In particular, the refrigerant flowing in the gap 42B between the outer cover 64 and the shell 44 effectively blocks the effect of heat transfer to the outside of the coil 40, and the highest temperature portion of the shell 44 is It is structured to be covered with a refrigerant in a low temperature state. That is, the low-temperature refrigerant that has just flowed into the outer gap 42B covers the high-temperature refrigerant immediately before recovery in the shell 44, so that in addition to improving the cooling efficiency of the coil 40, the amount of heat transferred to the external atmosphere is reduced. It can be significantly reduced.

Even when the flow of the refrigerant is disturbed by flowing in the gap 42B in the width direction Y, the outer second main flow path 7
6 and is guided again in the longitudinal direction X by the inner main flow path 56, so that the gap 42 on the surface of the coil 40
, A uniform flow can be formed in the longitudinal direction X. Further, the refrigerant which has cooled the coil 40 and turned into a high-temperature state is quickly recovered to the inner second main flow path 52 through the fine holes 54, so that refrigerant stagnation on the coil 44 is prevented and local High temperature conditions can be prevented. From this viewpoint, it is preferable to form the pores 54 as many as possible. Alternatively, the pores 54 may be formed in a slit shape to expand the flow path cross-sectional area of the pores 54.

Further, between the mounting surface 60 and the coil 40,
Outer first main flow path 7 (in which the refrigerant in the lowest temperature state is introduced)
Since 0 is interposed, the amount of heat transfer to the mounting surface 60 is suppressed, and the thermal expansion on the mating machine side is greatly reduced.

Further, in the first embodiment, since the refrigerant moves in the order of the supply hole 72 → the communication hole 78 → the discharge pipe 55, a counter flow is also formed in the longitudinal direction X as a whole. . In particular, a counterflow is clearly formed between the outer first main flow path 70 and the inner second main flow path 52, and between the outer second main flow path 76 and the inner main flow path 56. Uniform cooling has been achieved. Further, since the supply hole 72 and the discharge pipe 55 are close to each other, the external piping design becomes very easy.

The refrigerant having the highest temperature passes through the discharge pipe 55, but since the first main flow path 70 surrounds the discharge pipe 54 (see FIG. 6), the discharge pipe 5
5 to the mounting surface 60 can be reduced,
This also reduces the thermal expansion of the other machine.

Next, a coil unit 132 according to a second embodiment of the present invention will be described with reference to FIGS. The parts and members that are not specifically described below are the same as those of the coil unit 32 according to the first embodiment.
Therefore, the same parts are denoted by the same reference numerals in the lower two digits as those of the coil unit 32, and detailed description of the configuration, operation, and the like is omitted.

In the outer second main flow path 176 of the coil unit 132, a plurality of communication holes 178 for supplying a coolant to the inside of the shell 144 are formed at predetermined intervals in the longitudinal direction X. The outer second main flow path 176 can directly supply the coolant to the gap 42 through the communication holes 178. Therefore, the inner main flow path 56 in the coil unit 32 of the first embodiment is not formed (it can be said that the outer second main flow path 176 also functions as the inner main flow path).

Also in this coil unit 132, the refrigerant is guided in the longitudinal direction X by the outer first main flow path 170, and is drawn out in the width direction Y via the branch flow path 174. Further, also in the outer second main channel 176, the refrigerant is led out in the width direction Y via the plurality of communication holes 178. Therefore,
By the diffusion of the refrigerant in the longitudinal direction X and the counterflow in the width direction Y,
Almost the same effects as those of the first embodiment can be obtained, and the internal structure can be simpler than that of the first embodiment.

In the first and second embodiments, the case where the branch flow paths 74 and the communication holes 178 are arranged at equal intervals in the longitudinal direction has been described, but the present invention is not limited to this. There is no particular limitation on the length or shape of the branch flow path 74 or the communication hole 178.

Further, the concept of flowing the refrigerant in the width direction Y in the present invention takes into consideration the case where the coil unit is viewed as a whole. That is, while the conventional method actively flows the refrigerant in the longitudinal direction, the present invention positively flows in the width direction, so that the flow of the refrigerant in the width direction has some deviation or stagnation. Is also within the range assumed by the present invention.

The above-described coil units 32 and 132
Focuses on preventing the effect of heat transfer to the outside of the coil 40. However, in this structure, if the refrigerant flows in the opposite direction (if it flows backward), the heat dissipation structure that minimizes the temperature rise itself of the coil as much as possible Can be obtained.

Specifically, in the coil unit 32 shown in FIG. 5, the discharge pipe 55 is connected to the supply pipe and the inner second main flow path 5
2 may be a first guide path, the inner main flow path 56 may be a second guide path, and the supply hole 72 may be a discharge hole. With this configuration, the refrigerant supplied from the supply pipe (discharge pipe 55) is guided in the longitudinal direction X by the first guide path (the inner second main flow path 52), and the refrigerant is supplied to the surface of the coil 40 through the fine holes 54. It is derived in the width direction Y. The refrigerant that has cooled the coil 40 is received by the second guide path (the inner main flow path 56), and is led out to the gap 42 </ b> B between the shell 44 and the outer cover 64. The heat is effectively released to the outside by the outer cover 64, so that the coil 40
The refrigerant that has actively cooled the air is finally discharged to the discharge holes (the supply holes 7).
2).

[0072]

According to the coil unit of the present invention,
The cooling efficiency of the coil can be greatly increased, and the heat transfer to the surrounding atmosphere and the partner machine can be significantly suppressed. Therefore, the positioning accuracy of the partner machine by the linear motor can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a linear motor to which a coil unit according to a first embodiment of the present invention is applied;

FIG. 2 is a perspective view partially showing the linear motor.

FIG. 3 is a perspective view showing a coil piece used in the coil unit.

FIG. 4 is a perspective view showing a coil configured by combining a plurality of the same coil pieces.

FIG. 5 is a partial sectional view showing a cooling structure of the coil unit.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 5;

FIG. 8 is a sectional view showing a coil unit according to a second embodiment of the present invention.

9 is a sectional view taken along line IX-IX in FIG.

FIG. 10 is a sectional view showing a conventional linear motor.

11 is a sectional view taken along line 11-11 of FIG. 10;

FIG. 12 is a schematic diagram showing a state of diffusion of a refrigerant in a coil unit of the linear motor.

[Explanation of symbols]

 30 Linear motor 32, 132 Coil unit 34 Magnet unit 36 Magnet 42, 42B, 142, 142B Gap 44, 144 Shell 44A, 144A One end 44B, 144B Other end 52, 152 Inside 2 main flow paths 54, 154 ... pores 55, 155 ... discharge pipes 56 ... inner main flow paths 60, 160 ... mounting surfaces 64, 164 ... outer covers 66, 166 ... outer lids 68, 168 ... outer plates 70, 170 ... outer first 1 main flow path 74, 174 ... branch flow path 76, 176 ... outer second main flow path 78, 178 ... sub flow path 74, 174 ... branch flow path

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H02K 41/03 H02K 41/03 A F term (Reference) 3L044 AA04 BA06 CA12 DB02 KA04 5H609 BB08 PP02 PP06 PP07 PP08 PP09 QQ04 QQ05 QQ10 QQ14 QQ16 RR27 RR36 RR37 RR41 5H641 BB03 BB06 BB18 BB19 GG02 GG03 GG05 GG07 HH02 HH03 JB04

Claims (8)

[Claims] A coil disposed to face the magnet of the linear motor, the coil being housed inside the coil with a predetermined gap,
A shell capable of cooling the coil by passing a coolant through the gap;
A coil unit used in a linear motor having: an outer cover capable of accommodating the shell therein with a predetermined gap therebetween and cooling the shell through a coolant through the gap; and An outer first main flow path formed in the vicinity of one end in the width direction to extend in the longitudinal direction, to introduce the refrigerant supplied from the outside into itself, and to guide the refrigerant to the outer surface of the shell in the width direction; Receiving the refrigerant that is formed in the outer cover in the vicinity of the other end in the width direction of the shell in the longitudinal direction and that flows in the width direction on the outer surface of the shell via the outer first main flow path; A second outer main flow path capable of supplying the refrigerant into the shell; and a discharge pipe capable of discharging the refrigerant flowing through a coil surface in the shell to the outside. Coil unit. 2. The method according to claim 1, further comprising: forming a longitudinally extending portion on the side of the outer second main flow path in the shell, and introducing the refrigerant supplied from the outer second main flow path into itself. A coil unit for a linear motor, comprising: an inner main flow path through which the refrigerant can be guided in a width direction on a surface of a coil in the shell. 3. The cooling medium according to claim 1, further comprising: a coolant extending in a longitudinal direction on the outer first main flow path side in the shell and flowing in a width direction on a surface of the coil in the shell. A coil unit for a linear motor, comprising: an inner second main flow path that receives the refrigerant and discharges the refrigerant from the discharge pipe. 4. The outer first cover according to claim 1, 2 or 3, wherein the outer first cover is provided near one end of the outer cover in the longitudinal direction.
A supply hole capable of supplying the refrigerant is formed in the main flow path, and a communication hole capable of supplying the refrigerant guided therein to the inside of the shell is provided near the other longitudinal end of the outer second main flow path. A coil unit for a linear motor, wherein the discharge pipe capable of discharging the refrigerant is disposed at a position corresponding to the vicinity of the supply hole in the shell. 5. The coil for a linear motor according to claim 4, wherein the discharge pipe is provided so as to penetrate the vicinity of the downstream side of the supply hole in the outer first main flow path. unit. 6. The refrigerant according to claim 1, wherein a plurality of branch channels are formed in the outer first main channel at predetermined intervals in a longitudinal direction, and the refrigerant introduced into the outer first main channel. Is branched by each of the plurality of branch flow paths so as to be able to be led out to the outer surface of the shell in the width direction. 7. The branch flow path according to claim 6, wherein a longitudinal sub flow path capable of temporarily storing the refrigerant derived from the branch flow path is formed at a downstream end of the branch flow path. A coil unit for a linear motor, wherein the refrigerant can be led out to the outer surface of the shell in the width direction. 8. A coil disposed to face a magnet of a linear motor, and said coil is housed inside with a predetermined gap therebetween.
A shell capable of cooling the coil by passing a coolant through the gap;
A coil unit used in a linear motor having: an outer cover capable of accommodating the shell therein with a predetermined gap therebetween and cooling the shell through a coolant through the gap; and a width of the coil in the shell. A first guide passage formed in the vicinity of one end edge in the longitudinal direction and capable of introducing the refrigerant supplied from the outside into itself and guiding the refrigerant to the surface of the coil in the width direction; The coil is formed so as to extend in the longitudinal direction in the vicinity of the other end in the width direction of the coil, and receives the refrigerant flowing in the width direction on the surface of the coil through the first guide path. A second guide path that can be supplied to the gap with the outer cover; and a discharge hole that can discharge the refrigerant that has flowed on the outer surface of the shell to the outside. Coil units.