JP3750793B2 - Linear motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is a linear motor that is used in a feed mechanism of a machine tool or a positioning device of a semiconductor manufacturing apparatus, and that relatively moves with one of a field pole and an armature as a stator and the other as a mover. About.
[0002]
[Prior art]
Conventionally, a linear motor that is used in a feed mechanism of a machine tool or a positioning device of a semiconductor manufacturing apparatus and relatively moves with either one of a field pole or an armature as a stator and the other as a mover, It is as shown in FIG. FIG. 6 is a front sectional view of a conventional linear motor. Here, in conjunction with the prior art and the present invention to be described later, an example of a moving coil linear motor having an armature as a mover will be described.
In the figure, 1 is a fixed base, 2 is a linear guide, and is composed of a guide rail 2A provided at both left and right ends on the fixed base 1, and a slider 2B that constitutes a linear guide in pairs with the guide rail 2A. 3 is a linear motor, 4 is a stator, 5 is a mover, 6 is a flat field yoke fixed to the fixed base 1 so as to be opposed to each other, and 7 is along the field yoke 6 (in a direction perpendicular to the paper surface). ) A plurality of permanent magnets arranged so that the magnetic poles are alternately different, and the stator 4 is constituted by a field magnetic pole composed of the field yoke 6 and the permanent magnet 7. 8 is a core formed by facing the permanent magnet 7 through a magnetic gap and is formed by laminating electromagnetic steel plates in the height direction of the permanent magnet 7, and 9 is wound inside the slot 8A of the core 8. The armature composed of the core 8 and the coil 9 constitutes the movable element 5. Reference numeral 10 denotes a table for loading a load. When the core 8 is fixed to the table 10, the fastening bolt 11 is passed through the through hole 8 </ b> B provided in the core 8, and then the female screw portion 10 </ b> C provided in the table 10 is attached. The fastening bolt 11 is screwed to fasten the core 8 and the table 10.
Such a linear motor 3 is provided so that each permanent magnet 7 sandwiches both sides of the coil 9 and has a structure in which the magnetic lines of force of the permanent magnet 7 penetrate the coil 9, that is, a so-called magnetic flux penetrating structure. In the structure, no attractive force is generated between the coil 9 and the table, and no lateral force is applied to the table.
[0003]
[Problems to be solved by the invention]
However, in the conventional technique, in the illustrated moving coil type linear motor 3, if a drive current is continuously supplied from the power source (not shown) to the coil 9 in order to increase the thrust of the motor, the temperature rises due to an increase in the internal resistance of the coil 9. And the calorific value increases. For this reason, the heat generated from the coil 9 is transferred through the core 8 to the table 10 fixed to the upper portion of the core 8, causing a problem that the core 8 and the table 10 are thermally deformed. In particular, at the portion of the core 8 facing the fixing base 1, the warpage due to thermal deformation that occurs in the longitudinal direction increases as the coil temperature rises with time.
In addition to such a moving coil type linear motor, there are the following common problems in the case of a moving magnet type linear motor (not shown) having a field pole as a mover.
(1) When the heat generation of the coil 9 of the linear motor 3 is large, the deformation in the direction facing the magnet row of the permanent magnet 7 of the core 8 also increases, and the magnetic gap between the coil 9 and the permanent magnet 7 fluctuates. As a result, cogging thrust is generated. As a result, when the cogging thrust is increased, the running performance of the linear motor 3 is deteriorated, and particularly the machining accuracy is greatly affected.
(2) Thermal deformation accompanying heat transfer to the other table 10 adversely affects the slider 2B attached to the table 10 or a scale used for a linear encoder (not shown) and causes an error in positioning accuracy. It was difficult to achieve positioning.
(3) In the linear motor 3, thermal deformation occurred in a resin mold (not shown) covering the coil 9 with the influence of the temperature rise of the coil 9, which caused breakage of the resin mold.
(4) For example, when the linear motor 3 is used in a vacuum environment, if the resin mold is damaged, the linear motor 3 increases the amount of dust generated by the gas generated from the surface of the resin mold. It was lacking in reliability.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a highly accurate and highly reliable linear motor that eliminates thermal deformation of the core and the table.
[0004]
[Means for Solving the Problems]
In order to solve the above problem, the present invention according to claim 1 is arranged such that a field pole in which a plurality of permanent magnets having different magnetic poles are alternately arranged along a field yoke, and the field pole and a magnetic gap are arranged. and a armature formed by winding a plurality of coil core having a slot with, on either the stator of the field pole and the armature, the other as the movable element, wherein the movable element fixing In the linear motor that is relatively moved along the longitudinal direction of the child, the mover is provided with a table for loading a load, and an inner portion is provided between the mover and the table. a cooling unit having a coolant passage for circulating a coolant Yes is provided, on the mover, heat dissipating the heat receiving portion in the direction of the plane orthogonal to the opposed faces through the stator and the magnetic air gap And has a substantially L-shape Provided a bent thin sheet-like heat pipe, the heat receiving portion of the sheet-shaped heat pipe to the surface of the movable element is a part of the heat radiating portion which is brought into contact with the cooling unit.
According to a second aspect of the present invention, in the linear motor according to the first aspect, the sheet-like heat pipe has a structure in which a number of hollow thin tubes meandering are arranged.
According to a third aspect of the present invention, in the linear motor according to the first or second aspect, the sheet-like heat pipe is integrally fixed to the surface of the movable element by a resin mold.
According to a fourth aspect of the present invention, in the linear motor according to any one of the first to third aspects, the cooling unit is provided with a fastening bolt so that the cooling unit can be freely detached from the movable element or the table. It is fixed.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a linear motor according to an embodiment of the present invention, and is a front sectional view taken along line AA of FIG. FIG. 2 is an overall perspective view of the linear motor in FIG. 1 and shows a state in which a table, a linear guide, and a fixed base are removed. FIG. 3 is a plan view of the cooling unit and armature of the linear motor shown in FIG. 2 as viewed from above, and the inside thereof is seen through. 4 is a side view of the cooling unit and armature portion of the linear motor shown in FIG. 3 as seen from the direction of arrow B, and the inside thereof is seen through. In addition, in the component of this invention, about the same component as the past, the same code | symbol is attached | subjected and description is abbreviate | omitted and only a different point is demonstrated.
In the figure, 12 is a cooling unit, 13 is a refrigerant passage, 13A is a refrigerant inlet, 13B is a refrigerant outlet, 14 is a sheet-like heat pipe, and 15 is a resin mold.
The present invention is different from the conventional one as follows.
A cooling unit 12 having a refrigerant passage 13 for circulating a refrigerant therein is provided between the armature as the mover 5 and the table 10. The refrigerant passage 13 is provided with a refrigerant inlet 13A at one end of the cooling unit 12 and a refrigerant outlet 13B at the other end so that the refrigerant flows in the longitudinal direction of the cooling unit 12. Further, the cooling unit 12 is inserted into the through hole 10A provided in the table 10 so that the cooling unit 12 can be freely removed from the table 10, and then the fastening bolt 16 is screwed into the female screw portion 12A of the cooling unit 12 to be fixed to the table. 10 recesses 10B are fixed. Further, the cooling unit 12 is passed through the through-hole 8B of the core 8 so that the cooling unit 12 can be freely removed from the mover 5, and then the fastening bolt 11 is screwed into the female screw portion 12A of the cooling unit 12 so that the mover 5 Is fixed.
The mover 5 has a heat receiving portion and a heat radiating portion on a surface orthogonal to a surface facing the magnet row of the permanent magnet 7 as a stator through a magnetic gap, and is thin and foldable. A sheet-like heat pipe 14 is provided. As shown in FIGS. 2 and 4, the sheet-like heat pipe 14 is bent into a substantially L shape, the heat receiving portion of the sheet-like heat pipe 14 is brought into contact with the surface of the armature, and a part of the heat radiating portion is a cooling unit. 12 is contacted. The said heat pipe can be attached to all installation directions, without limiting the installation direction of a heat receiving part and a thermal radiation part.
Next, the internal structure of the sheet-like heat pipe 14 will be specifically described. FIG. 5 is an overall perspective view of the sheet-like heat pipe, and the inside is seen through.
This sheet-like heat pipe 14 has a structure in which a large number of meandering hollow thin tubes 14A are arranged inside a thin metal plate member having good heat conduction, and is a two-phase made of a liquid phase working fluid such as Freon and a gas phase working fluid. The hydraulic fluid is sealed in the thin tube 14A. When fixing the sheet-like heat pipe 14 to the armature, the heat receiving portion 14B of the sheet-like heat pipe 14 shown in FIG. 5 is bent into a substantially L shape, and the surface of the armature shown in FIG. It is arranged so as to cover a portion exposed to the outside of the end 9A, and is fixed integrally with the resin mold 15. At this time, the heat radiating portion 14C of the sheet-like heat pipe 14 is preferably disposed so as to protrude from the tip of the end face of the armature in order to contact the cooling unit 12.
[0006]
Next, the operation of the linear motor will be described.
In the above configuration, when a drive current is supplied from a power source (not shown) to the coil 9, the mover 5 generates a constant thrust and the coil 9 generates heat due to an internal resistance. The heat generated in the coil 9 is transmitted to the heat receiving part 14B of the sheet-like heat pipe 14, and when the heat receiving part 14B absorbs heat, intense nucleate boiling occurs. Pressure waves due to intermittent nucleate boiling become vibration waves, causing vibrations in the working fluid sealed in the narrow tube 14A, and a large amount of heat is transmitted to the heat radiating portion 14C due to the vibrations of the working fluid. The heat transferred to the heat radiating portion 14 </ b> C of the sheet-like heat pipe 14 is transferred to the refrigerant passage 13 provided inside the cooling unit 12. The refrigerant supplied to the refrigerant inlet 13A of the refrigerant passage 13 flows toward the refrigerant outlet 13B as shown in the figure, and the heat generated in the armature part is removed by the refrigerant and heat exchange is performed. As a result, the heat generated in the coil 9 is efficiently radiated by the cooling unit 12 and the temperature rise of the coil 9 is suppressed, so that heat is not transferred to the table 10 side, but is transferred to the table 10 and is thermally deformed. Can be suppressed.
[0007]
Therefore, the present invention has a table 10 for mounting a load on the upper part of the armature that is the movable element 5, and has a refrigerant passage 13 for circulating a refrigerant between the movable element 5 and the table 10. The cooling unit 12 is provided, and the armature is provided with a thin sheet-like heat pipe 14 on a surface orthogonal to the surface facing the magnet row of the permanent magnet 7 that is the stator 4. Since the heat receiving portion 14B is brought into contact with the armature surface and a part of the heat radiating portion 14C is brought into contact with the cooling unit 12, for example, the heat of the armature portion generated when the mover is moved with high thrust is applied to the sheet heat pipe 14 And the refrigerant passage 13 can be efficiently removed. As a result, it is possible to suppress the thermal deformation of the armature part and the table 10 without transferring the heat generated by the armature part to the table 10, and to prevent the core 8 from warping in the longitudinal direction. Further, since the magnetic gap between the coil 9 and the permanent magnet 7 does not fluctuate, it is possible to provide a linear motor capable of positioning with high accuracy while suppressing the generation of cogging thrust.
Further, since there is no thermal deformation associated with heat transfer to the table 10, it does not affect the positioning accuracy error of the linear guide 2 and the linear scale, and a linear motor capable of high accuracy positioning can be provided.
Then, since the temperature rise of the coil 9 can be suppressed, damage due to thermal deformation of the resin mold 15 covering the coil 9 can be prevented. For example, even when the linear motor is used in a vacuum environment, Gas generation from the surface of the resin mold 15 can be prevented, and a highly reliable linear motor can be provided.
In the present invention, since the sheet-like heat pipe 14 has a structure in which a large number of hollow thin tubes 14A meandering inside are arranged, the thermal conductivity is extremely high for a small size, and heat can be transferred quickly. .
Furthermore, since the sheet-like heat pipe 14 is integrally fixed to the surface of the mover 5 by the resin mold 15 in the present invention, the sheet-like heat pipe 14 can be easily fixed to the surface of the mover 5.
Furthermore, in the present invention, the cooling unit 12 is fixed by the fastening bolts 11 and 16 so that the cooling unit 12 can be freely removed from the mover 5 or the table 10. It is easy to disassemble and saves time and money.
In addition, although the present Example demonstrated using the example of the linear motor of the magnetic flux penetration type | mold structure which has arrange | positioned the permanent magnet on both sides of the coil, the linear motor of the so-called gap opposing type structure which arrange | positions a permanent magnet on the one side of a coil. The same applies to the present invention.
[0008]
【The invention's effect】
As described above, the present invention has the following effects.
(1) According to the first aspect of the present invention, there is provided a table for mounting a load on the upper part of the armature that is the mover, and a refrigerant passage for allowing the refrigerant to flow between the mover and the table. The armature is provided with a thin sheet heat pipe on a surface orthogonal to the surface facing the magnet row of the permanent magnet as a stator, and the heat receiving portion of the sheet heat pipe Since the armature is in contact with the surface of the armature and a part of the heat radiating portion is in contact with the refrigerant passage, for example, the heat of the armature portion generated when the mover is moved with high thrust is efficiently generated by the sheet-like heat pipe and the refrigerant passage. Can be removed. As a result, it is possible to suppress thermal deformation of the armature part and the table without transferring heat generated by the armature part to the table, and to prevent warping in the longitudinal direction of the core. Further, since the magnetic gap between the coil and the permanent magnet does not fluctuate, it is possible to provide a linear motor that can suppress cogging thrust and can be positioned with high accuracy.
Further, since there is no thermal deformation associated with heat transfer to the table, there is no effect on positioning accuracy errors such as linear guides and linear scales, and a linear motor capable of high-precision positioning can be provided.
Furthermore, since the temperature rise of the coil can be suppressed, the resin mold covering the coil can be prevented from being damaged by thermal deformation. For example, even when the linear motor is used in a vacuum environment, the resin mold The generation of gas from the surface can be prevented, and a highly reliable linear motor can be provided.
According to the second aspect of the present invention, since the sheet-like heat pipe has a structure in which a large number of hollow thin tubes meandering are arranged inside, the heat conductivity is extremely high for the small size, and the movement of heat is small. It can be done quickly.
According to the third aspect of the present invention, since the sheet-like heat pipe is integrally fixed to the surface of the mover by the resin mold, the sheet-like heat pipe can be easily fixed to the surface of the mover.
According to the fourth aspect of the present invention, since the cooling unit is fixed to the movable element or the table by the fastening bolt so that it can be freely removed, assembly and disassembly with the movable element and the table are easy. Save time and money.
[Brief description of the drawings]
FIG. 1 is a front view of a linear motor according to an embodiment of the present invention, taken along line AA in FIG.
2 is an overall perspective view of the linear motor in FIG. 1, showing a state in which a table, a linear guide, and a fixed base are removed. FIG.
3 is a plan view of the cooling unit and the armature of the linear motor of FIG. 2 as viewed from above, and the inside thereof is seen through. FIG.
4 is a side view of the cooling unit and armature portion of the linear motor of FIG. 3 as seen from the direction of arrow B, and the inside thereof is seen through. FIG.
FIG. 5 is an overall perspective view of a sheet-like heat pipe as seen through the inside.
FIG. 6 is a front sectional view of a conventional linear motor.
[Explanation of symbols]
1: Fixed base 2: Linear guide 2A: Guide rail 2B: Slider 3: Linear motor 4: Stator (field part)
5: Movable element (armature part)
6: Field yoke 7: Permanent magnet 8: Core 8A: Slot 8B: Through hole 9: Coil 9A: Coil end 10: Table 10A: Female thread 10B: Recess 11, 11: Fastening bolt 12: Cooling unit 12A: Female thread 13: Refrigerant passage 13A: Refrigerant inlet 13B: Refrigerant outlet 14: Sheet heat pipe 14A: Thin tube 14B: Heat receiving part 14C: Heat radiating part 15: Resin mold

Claims (4)

A field pole in which a plurality of permanent magnets having different magnetic poles are arranged alternately along a field yoke, and a plurality of coils wound around a core having a slot and the field pole and magnetic gap. includes an armature, a,
One of the field pole and the armature is a stator, the other is a mover, and the mover is relatively moved along the longitudinal direction of the stator,
In linear motors,
The mover is provided with a table for loading a load,
Between the movable element and the table, a cooling unit having a refrigerant passage for circulating a refrigerant therein is provided,
Said movable element has a heat radiating portion and the heat receiving portion in the direction of the plane perpendicular to the opposing surfaces through the stator and the magnetic gap, and a thin sheet-like heat bent in a substantially L-shaped Pipes are provided,
A linear motor characterized in that a heat receiving portion of the sheet-like heat pipe is brought into contact with the surface of the mover and a part of a heat radiating portion is brought into contact with the cooling unit. The linear motor according to claim 1, wherein the sheet-like heat pipe has a structure in which a large number of hollow thin tubes meandering are arranged inside. The linear motor according to claim 1, wherein the sheet-like heat pipe is integrally fixed to a surface of the mover by a resin mold. The linear motor according to any one of claims 1 to 3, wherein the cooling unit is fixed to the movable element or the table by a fastening bolt so that the cooling unit can be freely removed.

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