JP2001327152A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized and highly reliable linear motor which can transmit the heat of an armature coil to a frame efficiently thereby preventing the drop of thrust of a needle accompanying the temperature rise of an armature coil. SOLUTION: In a linear motor 1 which is equipped with a field yoke 13 where a plurality of permanent magnets 12 alternately different in polarity are arranged linearly, an armature which has armature coils 4 being opposed through magnetic space to the row of the permanent magnets 12 and being constituted by molding a plurality of coil groups in plate form, and a frame 9 to which the armature is fixed and also which possesses a metallic block 11, a plate-shaped heat pipe 5 is provided between the two coil rows constituted of a plurality of coil groups, and it is fixed by resin mold 10, and also the heat absorptive section of the heat pipe 5 is arranged in the section opposed to the armature coil 4, and the heat radiating section is inserted into the metallic block 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor suitable for applications requiring ultraprecision positioning and high thrust, such as a transport system for FA equipment.

[0002]

2. Description of the Related Art Conventionally, a linear motor suitable for applications requiring ultra-precision positioning and high thrust, such as a transport system for FA equipment, is shown in FIG. The overall configuration of a conventional linear motor will be described with reference to FIG. FIG. 8 is a perspective view of a conventional linear motor mover, in which an armature coil is seen through. This example shows an example of a linear motor having a magnetic flux penetration structure in which permanent magnet arrays are arranged on both sides of an armature via magnetic gaps. In the figure, 1 is a linear motor, 2 is a mover, 3 is a stator, 4 is an armature coil, 9 is a metal frame, 10 is a resin mold, 12 is a permanent magnet, 13 is a field yoke, and 14 is a yoke. A base, 17 is a fixed winding frame, and 18 is a refrigerant passage. The linear motor 1
A plurality of permanent magnets 12 constituting a field pole are arranged in a straight line on the side surfaces of two rows of field yokes 13 so that the polarities of the N pole and the S pole are alternately different. The stator 3 is configured by disposing the yoke base 14.
Further, the linear motor 1 faces the row of the permanent magnets 12 via a magnetic gap, and forms a plurality of coil groups into a flat plate shape to form an armature coil 4 having two rows of coil rows.
Are arranged linearly on both surfaces of a winding fixing frame 17 made of metal such as stainless steel or resin, and the armature is fixed by a resin mold 10 to form the mover 2. . Further, a frame 9 for fixing the armature held by the winding fixing frame 17 is provided on the upper part of the armature along the longitudinal direction thereof,
A refrigerant passage 18 is provided inside the frame 9, and a refrigerant is supplied to the refrigerant passage 18 in the frame 9 from a refrigerant supply device (not shown). A linear guide composed of a slider and a guide rail (not shown) is attached to the mover 2 and the stator 3 of the linear motor so that the mover 2 moves linearly with respect to the stator 3. In such a configuration, when a current is applied to the armature coil 4 of each phase from a power supply (not shown), the electromagnetic force between the armature coil 4 and the permanent magnet 12 is applied to the armature coil 4 by the electromagnetic action of the permanent magnet 12. Electromagnetic force acts in the longitudinal direction of the armature coil 4 from the magnetic field formed in the gap to generate a thrust, thereby performing a smooth linear movement. At this time, when a drive current for propelling the mover 2 flows through the armature coil 4,
The armature coil 4 generates heat due to the internal resistance, and the heat generated by the armature coil 4 is transferred to the frame 9 through the resin mold 10 and the winding fixing frame 17 and then to the refrigerant passage 1.
The heat is exchanged by the refrigerant circulating in the inside of 8, and the entire armature is cooled.

[0003]

However, the prior art has the following problems. (1) The periphery of the armature coil 4 constituting the mover 2 is covered with a resin mold 10 having a very low thermal conductivity compared to the metal such as the armature coil 4 and the frame 9. The heat conduction between the armature coil 4 and the frame 9 is very poor, the distance from the end of the armature coil 4 to the frame 9 is long, and the winding fixing frame 1 holding the armature coil 4
Since the contact area between 7 and frame 9 is small, the thermal resistance of the path from armature coil 4 to the refrigerant passage of frame 9 is large. That is, the cooling capacity of the linear motor is
Since it is determined by the thermal resistance between the armature coil 4 and the frame 9, there is a limit only to a method of flowing the refrigerant to the frame 9 side, and the heat generated by the temperature rise of the armature coil 4 is efficiently radiated to the frame 9. I couldn't. (2) When the temperature of the armature coil 4 increases, the internal resistance of the armature coil 4 also increases, and the drive current decreases. However, since the thrust of the mover 2 of the linear motor 1 is proportional to the drive current, The decrease in the drive current has greatly reduced the thrust of the mover 2 of the linear motor 1. (3) If the temperature rise of the armature coil 4 is large as described above, the resin mold 1 that generally covers the armature coil 4
Although 0 causes thermal deformation due to the temperature rise due to the heat generated by the armature coil 4, the temperature rise is small in the frame 9 through which the refrigerant flows, and no thermal deformation occurs. For this reason, distortion occurs between the resin mold 10 and the frame 9, and the resin mold 10 having low strength may be damaged. Further, when the linear motor is used as a stepper drive mechanism of a semiconductor manufacturing apparatus or the like that operates in a vacuum environment, when the temperature of the resin mold 10 rises due to heat generated by the armature coil 4, gas is generated from the surface of the resin mold 10. However, it contaminates the vacuum environment required for the manufacturing process, and thus lacks reliability as a cooling device for a linear motor. (4) As another conventional technique, although not shown, a linear motor having a structure in which a plurality of heat sinks for flowing a coolant are arranged between adjacent coils formed between the same armature coil rows. However, since a heat sink is externally attached to the outside of the winding fixing frame that fixes the armature coil, covering them with resin mold increases the size of the entire armature and increases the number of assembly steps. , Could not be miniaturized. The present invention has been made in order to solve the above-described problems, and can efficiently transfer heat of an armature coil to a frame, and prevent a decrease in thrust of a mover due to a rise in temperature of an armature coil. An object is to provide a small and highly reliable linear motor.

[0004]

In order to solve the above-mentioned problems, a first aspect of the present invention is directed to a field device in which a plurality of permanent magnets constituting a field pole are arranged in a straight line so as to alternately have different polarities. A yoke, an armature disposed in parallel and opposed to the permanent magnet row via a magnetic gap, and a frame fixing the armature, and having a heat sink, wherein the armature has a longitudinal direction. An armature coil formed by arranging a plurality of coil groups toward each other to form a flat plate shape, one of the field pole and the armature as a stator, the other as a mover, and the field pole and In the linear motor configured to relatively move the armature, the armature coil is provided with a flat heat pipe along a longitudinal direction of a coil row formed by a plurality of coil groups, and a resin is provided. Solid with mold Yes and the heat absorbing portion of the heat pipe is disposed in a portion opposed to the armature coil, in which the heat radiating portion of the heat pipe is inserted into the interior of the heat sink. According to a second aspect of the present invention, in the linear motor according to the first aspect, the permanent magnet array is disposed on both sides of the armature via a magnetic gap, and the armature coil is connected to the permanent magnet array. And at least two coil arrays facing each other, and the heat pipe is inserted between the opposed coil arrays. According to a third aspect of the present invention, in the linear motor according to the first or second aspect, the heat sink is a metal block having high thermal conductivity. Claim 4 of the present invention provides claim 1
Alternatively, in the linear motor described in 2, the heat sink is formed of a hollow cooling jacket for flowing a coolant so that the inside of the frame can exchange heat with the coolant. Claim 5 of the present invention provides Claims 1 and 2,
Or in the linear motor according to any one of the above items 4,
The heat sink has a heat radiating fin provided on a heat radiating portion of the heat pipe. According to a sixth aspect of the present invention, in the linear motor according to any one of the first to fifth aspects, the heat pipe includes a meandering hollow thin tube for enclosing a working fluid inside a thin plate member. Things. According to a seventh aspect of the present invention, in the linear motor according to any one of the first to sixth aspects, the heat pipe is made of stainless steel.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall perspective view of a linear motor common to the present invention and the prior art, and FIG. 2 is a perspective view of a linear motor mover according to a first embodiment of the present invention, in which an armature coil is seen through. . FIG. 3 is a front sectional view of the linear motor of FIG. 1 taken along the line AA when viewed from the thrust direction, and FIG. 4 is an enlarged perspective view of the heat pipe, which is seen through.
FIG. 5 is a perspective view in which an armature coil is disposed on the heat pipe of FIG. Note that the same reference numerals are given to the same components as those of the present invention, and the description thereof will be omitted, and only different points will be described. Further, this embodiment shows an example of a linear motor having a magnetic flux penetration structure as in the conventional example. In the figure, 5 is a heat pipe, 6 is a thin tube, 6A is a heat absorbing section, 6B is a heat radiating section, 9A is a hole, and 11 is a metal block. The difference between the present invention and the conventional one is as follows. A thin, flat heat pipe having a heat absorbing portion 6A and a heat radiating portion 6B is arranged opposite to the armature coil 4 along a longitudinal direction of a coil array formed by forming a plurality of coil groups into a flat plate shape. . Specifically, this heat pipe 5 is inserted between two coil arrays, the heat absorbing portion of the heat pipe 5 is arranged and fixed at a portion facing the armature coil 4, and the heat radiating portion is provided inside the heat sink. Has been inserted. The heat sink has a metal block 11 having high thermal conductivity fitted into a hole 9A provided inside the frame 9 shown in FIG. Further, as shown in FIG. 4, the heat pipe 5 has a structure in which a number of meandering hollow thin tubes 6 are arranged inside a thin metal plate member having good heat conductivity. A two-phase working fluid composed of a phase working fluid is sealed in the thin tube 6. When fixing between the heat pipe 5 and the armature coil 4, as shown in FIG.
Is adhered with a thin resin or the like (not shown), and then the heat pipe 5, the armature coil 4, and the frame 9 are joined with a resin mold 10
It is more firmly fixed.

Next, the operation of the linear motor will be described. When a drive current flows through the armature coil 4 of the mover 2 of the linear motor, the armature coil 4 generates heat due to internal resistance.
The heat generated by the armature coil 4 is transmitted to the heat absorbing portion 6A of the heat pipe 5, and when the heat is absorbed by the heat absorbing portion 6A, intense nucleate boiling is generated. The pressure wave due to the intermittent nucleate boiling becomes a vibration wave, causing vibration in the working fluid sealed in the meandering thin tube 6, and a large amount of heat is transmitted to the heat radiation portion 6B by the vibration of the working fluid. Then, the heat transferred to the heat radiating portion 6 of the heat pipe 5 is transferred to the metal block 11, and as a result, the heat generated in the armature coil is efficiently transferred to the frame side, and the temperature rise is suppressed. Next, when the cooling capacity of the linear motor according to the present embodiment is calculated, the heat conductivity of the heat pipe 5 in the heat transfer direction is about 2000 W / m · ° C. or more. For example, the material of the conventional winding fixing frame is aluminum ( Thermal conductivity = about 2
(00 W / m · ° C.), and has a heat transfer capacity of 1000 times or more of the thermal conductivity (about 2 W / m · ° C.) of the resin mold 10. Therefore, conventionally, it is possible to efficiently remove heat to the vicinity of the end portion where the heat resistance of the armature coil 4 is high, and the temperature rise of the armature coil 4 and the resin mold 10 is reduced to at least 1/10 or less of the conventional case. can do. Therefore, the heat absorbing portion 6A and the heat radiating portion 6B are located between the two coil rows constituting the armature coil 4.
The heat pipe 5 has a thin and flat shape, and the heat absorbing portion of the heat pipe 5 is arranged and fixed so as to face the armature coil, and the heat radiating portion is inserted into the metal block 11. Armature coil 4 and resin mold 10
Temperature rise is greatly reduced, and cooling can be performed efficiently. Further, since the heat generated by the armature coil 4 can be efficiently dissipated, the drive current can be reduced without decreasing the drive current.
The thrust of the mover 2 can be increased. As a result, it is possible to prevent the resin mold 10 covering the armature coil 4 from being damaged due to thermal deformation, which is caused by the effect of the temperature rise of the armature coil 4. Further, even when the present linear motor is used in a vacuum environment, generation of gas from the surface of the resin mold 10 can be prevented, and a highly reliable linear motor can be provided. Further, since the heat pipe 5 has a structure in which a number of meandering hollow thin tubes 6 having a heat absorbing portion and a heat radiating portion are arranged in a thin metal member having good heat conductivity, the weight can be reduced without reducing the strength. It is possible to provide a small-sized linear motor that can reduce the number of assembling steps while maintaining the shape and size of the conventional winding fixed frame.

Next, a second embodiment of the present invention will be described.
FIG. 6 is a front sectional view of the linear motor in the second embodiment, and is a sectional view of the linear motor of FIG.
This corresponds to a front sectional view along the line. The second embodiment is different from the first embodiment in that a hole 9A is provided in the frame 9 and a coolant (for example, cooling) is provided in the hole 9A so that the heat sink can exchange heat inside the frame 9 with the coolant. The point is that a hollow cooling jacket 15 for flowing water W) is provided. Note that the operation is basically the same as that of the first embodiment, so that the description is omitted. In the present embodiment, since such a configuration is used, heat generated by the armature coil 4 can be efficiently radiated, and the thrust of the mover 2 can be increased without reducing the drive current.

Next, a third embodiment of the present invention will be described. FIG. 7 is a front sectional view of the linear motor according to the third embodiment, and corresponds to a front sectional view taken along line AA of the linear motor of FIG. 1 when viewed from the thrust direction. The third embodiment differs from the second embodiment in that a heat radiating fin 16 is provided in the heat radiating portion of the heat pipe 5. Here, the illustration of the cooling jacket is omitted, and only the hole 9A is illustrated.
(For example, air A) is passed through the fins 16 to exchange heat transferred to the radiating fins 16. Note that the operation is basically the same as that of the first embodiment, and a description thereof will be omitted. In the present embodiment, since such a configuration is used, heat generated by the armature coil 4 can be efficiently radiated, and the thrust of the mover 2 can be increased without reducing the drive current. In the present embodiment, a configuration in which the armature of the linear motor is the mover and the field pole is the stator has been described as an example, but the configuration in which the armature of the linear motor is the stator and the field pole is the mover is described. It does not matter. Further, in this embodiment, the example of the linear motor having the magnetic flux penetration structure is shown, but the permanent magnet array is formed on a horizontal plane, and the armature is opposed to the upper side of the permanent magnet array via a magnetic gap. A linear motor having a gap-facing structure may be used. Further, in the present embodiment, the description has been made using an example in which the coil rows of the armature coils are two rows. However, the coil rows may have a three-row structure, in which case the combination of the number of coil rows and the number of phases is limited. Not something. The material of the heat pipe 5 may be a metal such as stainless steel or aluminum. When the heat pipe 5 is made of stainless steel, the eddy current of the metal portion of the heat pipe generated when the armature of the linear motor moves in the thrust direction along the row of the permanent magnets 12 is reduced, and the eddy current is generated. Accordingly, the viscous resistance of the mover can be reduced. Heat pipe 5
Has shown an example in which a liquid-phase working liquid and a gas-phase working liquid are sealed in a meandering thin tube 6 to have a cooling property utilizing a nucleate boiling phenomenon. However, if such a cooling property is not satisfied, Other heat pipes may be used.

[0009]

As described above, the present invention has the following effects. (1) A thin, flat heat pipe having a heat absorbing portion and a heat radiating portion is provided between two coil rows constituting an armature coil, and the heat absorbing portion of the heat pipe is arranged so as to face the armature coil. Since the heat sink is fixed and the heat radiating portion is inserted into the metal block, the temperature rise of the armature coil and the resin mold is greatly reduced, and the cooling can be performed efficiently. (2) Further, since the heat generated by the armature coil can be efficiently radiated, the thrust of the mover 2 can be increased without reducing the drive current. (3) Further, it is possible to prevent the resin mold covering the armature coil from being damaged by thermal deformation, which is caused by the effect of the temperature rise of the armature coil. Further, even when the present linear motor is used in a vacuum environment, gas generation from the surface of the resin mold can be prevented, and a highly reliable linear motor can be provided. (4) Further, the heat pipe has a structure in which a number of meandering hollow thin tubes having a heat absorbing portion and a heat radiating portion are arranged in a thin metal member having good heat conductivity, so that the weight is reduced without lowering the strength. It is possible to provide a small linear motor capable of reducing the number of assembly steps while maintaining the shape and size of the conventional winding fixed frame.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a linear motor common to the present invention and the prior art.

FIG. 2 is a perspective view of a mover of the linear motor according to the first embodiment of the present invention, which is seen through an armature coil.

FIG. 3 is a view of the linear motor shown in FIG.
It is a front sectional view along a line.

FIG. 4 is an enlarged perspective view of the heat pipe of FIG. 3, as seen through the inside;

FIG. 5 is an enlarged perspective view in which an armature coil is provided on the heat pipe of FIG. 4;

FIG. 6 is a front sectional view of the linear motor according to the second embodiment, which is a view of the linear motor of FIG.
This corresponds to a front sectional view along the line A.

FIG. 7 is a front sectional view of a linear motor according to a third embodiment, showing the linear motor of FIG.
This corresponds to a front sectional view along the line A.

FIG. 8 is a perspective view of a conventional linear motor mover,
This is a perspective view of the armature coil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Linear motor 2 Mover 3 Stator 4 Armature coil 5 Heat pipe 6 Thin tube 6A Heat absorption part 6B Heat dissipation part 9 Frame 9A Hole 10 Resin mold 11 Metal block (heat sink) 12 Permanent magnet 13 Field yoke 14 Yoke base 15 Cooling Jacket (heat sink) 16 Radiation fin (heat sink) 17 Winding fixing frame 18 Refrigerant passage

Continued on the front page F term (reference) 5H609 BB08 PP02 PP06 PP07 PP09 QQ02 QQ04 QQ23 RR37 RR61 RR63 5H641 BB06 BB18 BB19 GG02 GG03 GG05 GG07 GG11 GG12 HH02 HH03 HH06 JB03 JB05 JB10

Claims (7)

[Claims] 1. A field yoke in which a plurality of permanent magnets constituting a field pole are alternately arranged in a line so as to have alternately different polarities, and an electric machine which is arranged in parallel with the row of permanent magnets via a magnetic gap. Armature, and a frame to which the armature is fixed, and provided with a heat sink, wherein the armature is an armature coil formed by arranging a plurality of coil groups in the longitudinal direction and forming a flat plate shape. A linear motor, wherein one of the field pole and the armature is a stator and the other is a movable element, and the field pole and the armature run relatively to each other. A flat heat pipe is provided along a longitudinal direction of a coil row formed by a plurality of coil groups, and is fixed with a resin mold. The heat absorbing portion of the heat pipe faces the armature coil. Linear motor, characterized in that that disposed in the portion, are inserted a heat radiating portion of the heat pipe in the interior of the heat sink. 2. The permanent magnet array is disposed on both sides of the armature via a magnetic gap, and the armature coils are formed by at least two coil arrays so as to face each other along the permanent magnet array. 2. The linear motor according to claim 1, wherein the heat pipe is inserted between the opposed coil arrays. 3. 3. The linear motor according to claim 1, wherein the heat sink is a metal block having high thermal conductivity. 4. The linear motor according to claim 1, wherein the heat sink is constituted by a hollow cooling jacket for flowing the refrigerant so that the inside of the frame can exchange heat with the refrigerant. . 5. The linear motor according to claim 1, wherein the heat sink is provided with a heat radiation fin at a heat radiation portion of the heat pipe. 6. The linear motor according to claim 1, wherein the heat pipe includes a meandering hollow thin tube for enclosing a working fluid inside a thin plate member. . 7. The linear motor according to claim 1, wherein the heat pipe is made of stainless steel.