JP2001275337A - Coil unit for linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of a heat of a coil unit on a circumference by uniformly cooling the unit coil, in the longitudinal direction. SOLUTION: The coil unit 32 for a linear motor comprises a flat plate-like coil 40 long in an advancing direction of the motor 30, and a shell 44 for containing the coil 40 via a prescribed gap 42 therein and enabling cooling of the coil via a refrigerant. The unit 32 further comprises a main channel 52, formed by extending in the longitudinal direction X of the coil 44 in the shell 44, to enable an introduction of the refrigerant supplied from an exterior into itself, and a plurality of branch channels 54 formed at a prescribed interval in the direction X at the channel 52, to enable a discharge of the refrigerant introduced into the channel 52 in the lateral direction Y of the coil 44. In this case, the refrigerant, discharged from the channel 54 via the channel 52, flows to the gap 42 between the shell 44 and the coil 40, to cool the coil 40 along the direction Y.

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 by 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 major 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), coil units as shown in FIGS. 7 and 8 have 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 magnets 3 attached to opposed inner walls 4 </ b> A in the base 24.

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, radiation to the surrounding atmosphere is reduced, and heat transfer of the coil 12 to the mounting surface 16 is reduced. It is suppressed, and the thermal expansion on the partner machine side is also reduced.
Therefore, in the linear motor 1, the influence of the heat generated by the coil 12 on the outside is reduced, and more accurate positioning is possible.

[0013]

However, even in such a coil unit 10, it cannot be said that a sufficient cooling effect is always obtained. Specifically, the state of diffusion of the refrigerant in the shell 14 is schematically shown in FIG. 9, and the refrigerant gradually spreads to A, B, C,..., Becomes a parallel flow, and finally converges to F, G, H. While being discharged from the discharge hole 20. 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. In particular, when the design is not good, there is a high possibility that a portion where the refrigerant hardly flows actually occurs, and the problem may become more remarkable.

In order to solve this, it is necessary to increase the cooling efficiency by increasing the flow rate of the refrigerant.
There are problems that the pressure of the refrigerant inside increases and the shell 14 curves outward, and that the capacity of the circulation pump for the refrigerant must be increased.

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 uniformly cools the entire coil without increasing the flow rate of the refrigerant. It is another object of the present invention to provide a linear motor coil unit that minimizes the external influence due to the temperature rise of the coil.

[0018]

According to the present invention, there is provided a coil which is disposed opposite to a magnet of a linear motor, the coil is accommodated in a predetermined gap, and the coil can be cooled by passing a coolant through the gap. A main flow path formed inside the shell in the longitudinal direction of the coil and capable of introducing a refrigerant supplied from the outside into the coil unit used in the linear motor including the shell; A plurality of branch flow paths formed in the main flow path at predetermined intervals in the longitudinal direction and capable of deriving the refrigerant introduced into the main flow path in the width direction of the coil, and the refrigerant drawn out of the branch flow path through the main flow path. The above object is achieved by allowing the coil to be cooled by flowing in a gap between the shell and the coil.

In this coil unit, the refrigerant is introduced and stored in the longitudinal direction of the coil, and the stored refrigerant is branched in the width direction. Specifically, first, the refrigerant is introduced in the longitudinal direction of the coil by the main flow path, and the refrigerant is led out from the plurality of branch flow paths in a state where the pressure in the main flow path is increased substantially uniformly in the coil longitudinal direction. Has become. Therefore, since the coil can be cooled along the width direction at each position in the longitudinal direction, the coil is more uniformly cooled unlike the conventional structure in which the refrigerant flows mainly in the longitudinal direction over the entire coil surface. Thus, a local temperature rise can be prevented.

Further, even when the flow rate of the refrigerant is increased, only the pressure resistance around the main flow path needs to be increased, and the branch flow path serves as a cushioning material, and the pressure is substantially uniform over the longitudinal direction of the shell. A distribution can be obtained. Therefore, it is possible to prevent the upstream side from being locally high pressure as in the related art, and it is possible to make the shell thinner, and as a result, it is possible to further reduce the weight.

In the above invention, the main flow path in the longitudinal direction is arranged near one end of the coil in the width direction, and flows along the surface of the coil in the width direction near the other end of the coil in the width direction. It is preferable to form a second main flow path in the longitudinal direction for receiving the cooled refrigerant.

With this arrangement, the refrigerant flowing through the gap between the coil and the shell (at a certain high pressure) positively flows into the second main flow path to release its own pressure. As a result, a pressure gradient is formed in the width direction from the main flow path side to the second main flow path side, so that the refrigerant flows uniformly in the width direction, and the coil is further cooled evenly over the entirety. This can be said to be particularly suitable for cooling a coil having a somewhat large dimension in the width direction.

Further, in the above-described invention, a longitudinal sub-flow path capable of temporarily storing the refrigerant led out through the branch flow path is formed at the downstream end of the branch flow path, and the sub-flow path is formed through the sub-flow path. Preferably, the refrigerant can be released to the coil surface.

With this arrangement, the refrigerant flowing into each branch flow path with the pressure equalized from the main flow path flows into the sub flow path, and the pressure distribution of the refrigerant is again diffused in the longitudinal direction in the sub flow path. You. Therefore, even if a slight pressure deviation remains between the branch flow paths, the refrigerant can flow in the width direction from the entire sub flow path at a pressure more averaged over the entire longitudinal direction of the coil. In other words, the sub-flow path serves as a so-called buffer, and further uniformity of the refrigerant independently drawn from each branch flow path is achieved.

Still further, in the above invention, the main channel in the longitudinal direction is arranged near one end in the width direction of the coil, and the coil unit is mounted on the outer peripheral surface of the shell opposite to the coil via the main channel. It is preferable to form a mounting surface that can be connected to the mating member, and to suppress transmission of heat of the coil to the mounting surface by a main flow path interposed between the mounting surface and the coil.

This coil unit (including a movable member) can be either a stator or a mover.
Must be connected to the mating member. According to the above configuration, since the main flow path through which the refrigerant in the coldest state (before cooling the coil) passes is interposed between the coil and the mounting surface, the heat of the coil is transmitted to the mounting surface. Can be suppressed very effectively. Further, since the direction of heat transfer from the coil to the mounting surface and the direction of flow of the refrigerant toward the coil surface via the main flow path and the branch flow path are opposed to each other, it is difficult for the heat of the coil to move to the mounting surface side. As a result, the uniform cooling effect over the entire longitudinal direction of the coil, the prevention of heat transfer to the mounting surface, and the like can be extremely reasonably compatible.

Further, in the above invention, it is preferable that the predetermined interval in the longitudinal direction at which the plurality of branch flow paths are formed is set so as to narrow from the upstream side to the downstream side of the refrigerant flowing in the main flow path. This is based on the following idea.

In any of the above-described inventions, since the cold refrigerant is first actively guided in the longitudinal direction of the coil by the main flow path, even in a portion distant from the refrigerant supply hole, the cold refrigerant is kept in the cold state. The coil can be cooled using a refrigerant. However, since the pressure of the refrigerant supplied from the supply hole to the main flow path tends to decrease as the distance from the supply hole increases, depending on the inflow resistance into each branch flow path (although it is in a cold state). The flow rate may decrease. In such a case, according to the above configuration, the interval at which the branch flow path is formed from the upstream side to the downstream side of the refrigerant flowing in the main flow path (that is, as the distance from the supply location of the refrigerant) increases becomes smaller. Thus, it is possible to prevent a decrease in the flow rate of the refrigerant on the downstream side, and to obtain a more uniform cooling effect.

The interval may be set so that a plurality of branch channels are set as one set, and each set is gradually narrowed. Further, there is a case where the branch flow paths cannot be arranged evenly over the entire longitudinal direction due to design reasons, but even in such a case, a plurality of branch flow paths formed in the main flow path are captured as a whole and The present invention also includes a concept of setting the width narrower from the side toward the downstream side. Furthermore, while being set narrower toward the downstream as a whole,
Since the pressure tends to increase due to the reaction force in the vicinity of the downstream end of the main flow path in the longitudinal direction, the present invention includes a concept of setting the interval slightly wider only in the vicinity of the downstream end.

Further, as a similar idea as described above, at least one of the gap between the coil and the shell or the cross-sectional area of the branch passage is increased from the upstream side to the downstream side of the refrigerant flowing in the main passage. Is preferred. Also in this case, the decrease in the flow rate due to the pressure loss on the downstream side can be compensated for by the increase in the gap and the increase in the cross-sectional area, so that a more uniform cooling effect can be obtained.

In the above invention, in the case where the second main flow path in the longitudinal direction is formed near the other end in the width direction of the coil, one end is further opened on the outer peripheral surface of the shell on the main flow path side, and the other end is further opened. A widthwise discharge pipe communicating with the second main flow path in the shell is provided so that the refrigerant guided to the second main flow path is discharged through the discharge pipe, and the outer peripheral surface of the discharge pipe is removed. Preferably, the refrigerant flows from the main flow path toward the second main flow path to suppress the heat of the discharge pipe from being transmitted to the shell.

Generally, in such a cooling structure using a refrigerant, the temperature of the refrigerant rises further downstream, so that the temperature near the discharge port becomes the highest. In any of the above-mentioned inventions, the coil is cooled uniformly, but in the portion where the cooled refrigerant is recovered, the heat eventually gathers, so that the surroundings are likely to become high in temperature. Even in this case, according to the configuration described above, the vicinity of the opening of the discharge pipe is directly covered by the refrigerant (in a cold state) guided by the main flow path, and the refrigerant flowing in the width direction around the discharge pipe is used to cover the vicinity. Since the discharge pipe itself is cooled, the heat of the discharge pipe is prevented from being transmitted to the shell and the surrounding atmosphere, and even when the high-temperature refrigerant is discharged, the influence on the outside can be suppressed to a very small level. That is, even when the high-temperature refrigerant is discharged by the discharge pipe arranged in the width direction, the refrigerant flows around the discharge pipe so as to face the discharge direction. The effect of heat can be kept small.

In addition, since the structure is such that the refrigerant can be supplied from the main flow path side and discharged from the main flow path side, assembly to the partner machine and piping design for the refrigerant become easy.

[0034]

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. The magnet unit 34 includes a base 38 having a U-shaped cross section. The magnets 36 are attached to an inner wall 38A of the base 38.

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 is provided. The plate 50 includes the coil 40
Is bent so as to follow the I-shaped cross section of the coil 40, and the linear portion 46 of the coil 40 is
A predetermined gap 42 is formed in A.

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

A main flow path 52 is formed near one end 40A of the coil 40 in the width direction. This main channel 52
Inside the shell 44 (specifically, inside the coil holder 48)
The cooling medium supplied from the liquid supply port 55 which opens in the outer peripheral surface of the shell 44 can be introduced and stored in itself. In the main flow path 52, a branch flow path 54 that can guide the refrigerant introduced into the main flow path 52 in the width direction Y is formed in a longitudinal direction X.
Are formed at predetermined intervals. As a result, the refrigerant derived from the branch flow path 54 via the main flow path 52 is
4 flows in the width direction Y in the gap 42 between the coil 4 and the coil 40, and the coil 40 is cooled along the width direction Y. In addition, the main flow path 52 and the branch flow path 54
May be formed in a groove shape in the coil holder 48 before being integrally molded, and may be configured when the resin G is filled.

In the vicinity of the other end 40B in the width direction Y of the coil 40, a second main flow path 56 in the longitudinal direction X capable of receiving the refrigerant flowing in the width direction Y on the surface (gap 42) of the coil 40 is provided. Is formed. More specifically, the other end edge 40 is smaller than the gap 42 formed in the linear portion 46A of the coil 40.
The plate 50 is bent so that the space around the B-side bent portion 46B is expanded, and the space between the plate 50 and the bent portion 46B forms the second main flow path 56.

As shown in FIG. 1, a plurality of branch passages 54
At the downstream end 54A, a sub-flow path 58 in the longitudinal direction X capable of storing the refrigerant drawn out from the branch flow path 54 is formed. In particular, in the present embodiment, the downstream ends 5 of the plurality of branch passages 54
4A is made continuous by the sub flow path 58. This is also similar to the second main flow path 56 described above, and the coil 40
The auxiliary flow path 58 is configured such that the space defined by the bent portion 46B on the one end edge 40A side and the plate 50 is expanded. The sub flow path 58 stores the refrigerant discharged from the branch flow path 54 again, and thereafter discharges the refrigerant to the gap 42.

As shown in FIG. 1, the shell 44 on the opposite side of (the one edge 40A of) the coil 40 through the main flow path 52
The coil unit 3 is provided on the outer peripheral surface of the (coil holder 48).
An attachment surface 60 capable of connecting the second member 2 to a mating member is formed. Therefore, the heat of the coil 40 is prevented from being transmitted to the mounting surface 60 by the main flow path 52 interposed between the mounting surface 60 and the coil 40.

As shown in FIG. 5, the liquid supply port 55 is open at one end in the longitudinal direction X of the mounting surface 60, and the liquid discharge port 62 is open at the other end. Inside the shell 44 near the drain port 62, two drain pipes 64 are arranged in the width direction Y, one end of which is open to the mounting surface 60 side continuously with the drain port 62, and the other end is a shell. It communicates with a second main flow path 56 in 44. As a result, the refrigerant guided to the second main flow path 56 is discharged from the liquid discharge port 62 via the discharge pipe 64.

Since the discharge pipe 64 is disposed inside the shell 44, the refrigerant discharged through the main flow path 52, the branch flow path 54, and the sub flow path 58 passes through the outer peripheral surface of the discharge pipe 64. It will flow toward the second main channel 56 side.
Therefore, since the discharge pipe 64 is covered with the refrigerant (which always flows), the heat of the warmed refrigerant in the discharge pipe 64 is prevented from being transmitted to the outside of the shell 44.

Next, the operation of the coil unit 32 according to the first embodiment will be described in detail.

The refrigerant supplied from the liquid supply port 55 is first introduced and stored in the longitudinal direction X along the main flow path 52.
When the pressure in the main channel 52 increases due to the continuously supplied refrigerant, the refrigerant is led out of each of the branch channels 54. Therefore, if the pressure in the main flow path 52 is uniform, the refrigerant having substantially the same flow rate is drawn from each branch flow path 54. The refrigerant drawn out from the downstream end 50A via the branch flow path 54 is temporarily stored in the sub flow path 58 and spreads at a stretch in the longitudinal direction X of the coil 40. Since the amount of the refrigerant introduced from each branch channel 54 into the sub-channel 58 has already been considerably uniformed in the longitudinal direction by the function of the main channel 52, the pressure of the refrigerant in the sub-channel 58 is increased in the longitudinal direction X. Is further uniformized. Then, the refrigerant in the sub flow path flows into the gap 42 between the coil 40 and the shell 44, and flows in the width direction Y. The coolant that has cooled the coil 40 (obtained heat from the coil 40) through the gap 42 flows into the second main flow path 56, and further,
When the pressure in the second main flow path 56 increases, the discharge pipe 6
4 and is discharged from the drain port 62.

According to the coil unit 32, the refrigerant is first introduced in the longitudinal direction X of the coil 40, and then the refrigerant is branched in the width direction Y. Can be cooled.
As a result, it is prevented that one end side (downstream side) in the longitudinal direction X is locally brought to a high temperature state as in the conventional structure.

Even when the flow rate of the refrigerant is increased in order to increase the cooling capacity, since the main flow path 52 and the branch flow path 54 are formed by the coil holder 48, they can sufficiently withstand the pressure of the refrigerant. . On the other hand, the main flow path 5
Since the refrigerant in 2 flows into the sub flow path 58 “in a state where the pressure is dispersed” via the branch flow path 54, the thickness of the plate 50 in the shell 44 does not need to be unnecessarily thick. In other words, the branch passages 54 have both a role of dispersing the flow of the refrigerant and a role of dispersing the pressure, and provide both efficient (uniform) cooling of the coil 40 and thinning of the shell 44. Will be compatible. As a result, as shown in FIG. 1, since the distance S between the opposed magnets 36, 36 can be shortened, a large driving force can be obtained with a small amount of electric power. When the coil unit 32 is a mover, its mass can be reduced, so that drive responsiveness and controllability can be improved.

Further, since the second main flow path 56 is formed in the coil unit 32, the pressure of the refrigerant is uniformly released in the second main flow path 56. As a result, a uniform pressure gradient is formed at each position in the longitudinal direction from the high pressure side main flow path 52 to the low pressure side second main flow path 56, and the refrigerant positively and uniformly flows in the width direction Y. Therefore, the coil 40 can be cooled in a more uniform state in the longitudinal direction X, and this structure is particularly suitable for a coil having a large flat plate area (dimensions in the longitudinal direction X and / or the width direction Y).

The presence of the sub flow path 58 causes the branch flow path 5
The pressure of the refrigerant derived from 4 is diffused in the longitudinal direction X,
Further, since the refrigerant flows into the gap 42 "from the whole" of the sub flow path 58, even if the arrangement interval of the branch flow paths 54 is slightly uneven, the coil 40 is cooled unevenly. Can be prevented. That is, the sub flow path 58 plays a so-called buffer role, and achieves more uniform cooling of the coil 40.

The main flow path 5 between the mounting surface 60 and the coil 40 through which the refrigerant before cooling the coil 40 is guided.
Since the cooling medium 2 is interposed, the heat of the coil 40 is cut off by the refrigerant in the low temperature state, so that heat transfer to the mating machine connected to the mounting surface 60 can be suppressed. Further, since the outer peripheral surface of the discharge pipe 64 from which the refrigerant “cooled” after cooling the coil 40 is discharged is covered with the refrigerant guided from the sub flow path 58, the heat of the discharge pipe 64 is transmitted to the outside of the shell 44. And the temperature rise of the surrounding atmosphere can be reduced. Further, since both the liquid supply port 55 and the liquid discharge port 62 are arranged on the mounting surface 60 side, the assembly of the linear motor 30 on the partner machine side and the piping design for the refrigerant are facilitated.

Next, a coil unit 132 according to a second embodiment will be described with reference to FIG. Note that parts and members not specifically described below are substantially the same as those of the coil unit 32 according to the first embodiment. Therefore, redundant description of the configuration, operation, and the like is omitted.

In the coil unit 132, the predetermined interval P in the longitudinal direction X where the plurality of branch flow paths 154 are formed is directed from the upstream side to the downstream side of the refrigerant flowing in the main flow path 152 (that is, the liquid supply port). (From 155 toward the drain port 162).

According to the coil unit 132, even if the pressure of the refrigerant guided in the main flow path 152 in the longitudinal direction X decreases as it moves away from the liquid supply port 155, the amount of the decrease in the pressure is reduced. Since the arrangement interval of the branch flow passages 154 is set to be small so as to compensate for the above, the flow rate of the refrigerant flowing on the surface of the coil 140 can be made uniform in the longitudinal direction X. Therefore, a large amount of refrigerant flows only on the upstream side in the longitudinal direction X, thereby preventing uneven cooling.

It is preferable that the arrangement interval P be appropriately set in consideration of the relationship between the sectional area of the branch passage 54 and the sectional area of the main passage 152.

Although not particularly shown, in addition to setting the arrangement interval P of the branch flow passages 154 to be gradually narrowed as in the second embodiment, the cross-sectional area of the branch flow passages 154 May be set to increase from the upstream side to the downstream side.
42 may be set to gradually increase. With this configuration, even when the pressure of the refrigerant decreases from the liquid supply port 155 to the downstream side, the flow rate reduction due to the pressure decrease can be compensated for by increasing the cross-sectional area or increasing the gap interval. A uniform flow rate in the longitudinal direction X can be obtained.

Further, in order to supplement the flow rate on the downstream side of the main flow path, the cross-sectional area of the main flow path may be set to increase from the upstream side to the downstream side.

Although all of the above-described embodiments of the present invention have been described as including the second main flow path, the sub flow path, and the return pipe, the present invention is limited to the case including the second main flow path, the sub flow path, and the return pipe. Instead, what is essential is that the coil has a structure including the main flow path and the branch flow path so as to uniformly cool the coil as a whole.
There is no particular limitation on the number and length shape of the branch channels, and the branch channels may be formed in a slit state in the longitudinal direction.

In addition, the sub flow path may be any as long as it can diffuse the refrigerant derived from the branch flow path in the longitudinal direction.
At the downstream end of each branch flow path, a sub-flow path having a predetermined length in the longitudinal direction X is independently formed, or a predetermined number of sub-flow paths are connected by connecting the downstream ends of a predetermined number of branch flow paths. A channel may be provided.

Further, the concept of flowing the refrigerant in the width direction Y of the coil takes into consideration the case where the coil is viewed as a whole. That is, while the conventional method actively flows the refrigerant in the longitudinal direction of the coil, the present invention actively attempts to flow the refrigerant in the width direction, and as a result, the refrigerant flows in the width direction. Even if there is some deviation or stagnation, or if there is a slight flow in the longitudinal direction, it is within the range assumed by the present invention.

[0062]

According to the coil unit of the present invention,
The coil can be cooled uniformly in the longitudinal direction and the width direction, and the external influence due to a local temperature rise can be reduced. Further, since the thickness of the shell is reduced, the driving efficiency and controllability of 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 perspective view showing a cooling structure of the coil unit.

FIG. 6 is a perspective view showing a coil unit according to a second embodiment of the present invention.

FIG. 7 is a sectional view showing a conventional linear motor.

8 is a sectional view taken along line VIII-VIII of FIG. 7;

FIG. 9 is a schematic view showing a state of diffusion of the refrigerant in the coil unit.

[Explanation of symbols]

 30, linear motors 32, 132, coil units 34, magnet units 36, magnets 42, 142, gaps 44, 144, shells 52, 152, main flow paths 54, 154, branch flow paths 56, 156, second main flow paths 60, 160: mounting surface 64, 164: discharge pipe

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuro Kato 2-1-1, Yatocho, Tanashi-shi, Tokyo Sumitomo Heavy Industries, Ltd. Inside Tanashi Works (72) Inventor Masanobu Suginamine 63-30 Yuyugaoka, Hiratsuka-shi, Kanagawa Prefecture No. Sumitomo Heavy Industries Machinery Co., Ltd. Hiratsuka Works (72) Inventor Daisuke Shinodaira 2-1-1 Tanidocho, Tanashi-shi, Tokyo Sumitomo Heavy Industries, Ltd. Tanashi Works F-term (reference) 5H609 BB08 BB11 BB19 PP09 QQ01 QQ09 QQ16 QQ18 QQ21 RR37 5H641 BB03 BB06 BB18 BB19 GG02 GG03 GG05 GG07 GG12 HH02 HH03 JB04 JB05

Claims (7)

[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: a main flow path formed inside the shell in a longitudinal direction of the coil and capable of introducing the refrigerant supplied from the outside into the main flow path; A plurality of branch passages formed at predetermined intervals in the longitudinal direction and capable of leading the refrigerant introduced into the main passage in the width direction of the coil, and being led out of the branch passage through the main passage. Said refrigerant,
A coil unit for a linear motor, characterized in that the coil can be cooled by flowing through the gap between the shell and the coil. 2. The coil according to claim 1, wherein the main flow path in the longitudinal direction is disposed near one end of the coil in the width direction, and flows along the surface of the coil in the width direction near the other end of the coil in the width direction. A coil unit for a linear motor, wherein a second main flow path in the longitudinal direction for receiving the refrigerant is formed. 3. The sub-flow passage according to claim 1, wherein a longitudinal sub-flow passage capable of temporarily storing the refrigerant derived from the branch flow passage is formed at a downstream end of the branch flow passage. A coil unit for a linear motor, wherein the refrigerant can be led out to the coil surface via a coil. 4. The shell according to claim 1, 2 or 3, wherein the main flow path in the longitudinal direction is arranged near one end in the width direction of the coil, and the outer periphery of the shell opposite to the coil via the main flow path. A surface on which a mounting surface capable of connecting the coil unit to a mating member is formed, and the main flow path interposed between the mounting surface and the coil suppresses transfer of heat of the coil to the mounting surface. A coil unit for a linear motor. 5. The cooling medium according to claim 1, wherein the predetermined interval in the longitudinal direction in which the plurality of branch flow paths are formed narrows from an upstream side to a downstream side of the refrigerant flowing in the main flow path. A coil unit for a linear motor, wherein the coil unit is set to be: 6. The cross-sectional area of the gap between the coil and the shell or the cross-sectional area of the branch flow path from the upstream side to the downstream side of the refrigerant flowing in the main flow path, according to any one of claims 1 to 5, At least one of the coil units is set to be large. 7. The discharge pipe according to claim 2, wherein one end is opened on the outer peripheral surface of the shell on the main flow path side, and the other end is provided with a discharge pipe in a width direction communicating with the second main flow path in the shell. So that the refrigerant guided to the second main flow path is discharged through the discharge pipe,
A linear motor, wherein the refrigerant flows on the outer peripheral surface of the discharge pipe from the main flow path side to the second main flow path side, so that heat of the discharge pipe is prevented from being transmitted to the shell. Coil unit.