JP4372319B2 - Linear motor and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a linear motor that moves a moving body relative to a fixed body and a manufacturing method thereof.
[0002]
[Prior art]
A coil-side linear motor on which three-phase (U-phase, V-phase, and W-phase) coils are wound and arranged at a predetermined pitch is opposed to a coil-side linear motor with a gap (air gap) therebetween. A three-phase AC synchronous linear motor having a magnet-side linear motor in which permanent magnets are arranged at a predetermined pitch is known. In such a three-phase AC synchronous linear motor, cogging and torque ripple are reduced depending on the ratio of the number of coils (magnetic pole cores) to be combined and the number of magnets. There is no need to narrow the portion, and it is not necessary to thicken the tip of the pole tooth.
[0003]
Normally, when a linear motor is employed in a control shaft feeder such as a machine tool, the linear motor is installed in a sealed space so that cutting waste or the like does not enter the air gap of the linear motor. As a result, since the heat generated from the coil is difficult to escape, the component parts of the machine tool are thermally expanded, the control position of the moving shaft is thermally displaced, and the machining accuracy may be lowered. As described above, in the linear motor, it is an important problem to be solved to efficiently cool the heat generated by the coil.
[0004]
Japanese Patent Application Laid-Open No. 63-157463 discloses a linear motor that is provided with a cooling pipe in contact with the coil portion of the driving electromagnet and removes heat generated in the coil portion by a heat transfer medium flowing in the cooling pipe. It is disclosed. Japanese Laid-Open Patent Publication No. 9-238449 discloses a linear motor in which a cooling means for cooling a driving coil is provided for each driving coil. All of these linear motors can improve the cooling efficiency because the heat generated by the coils is cooled by the refrigerant.
[0005]
[Problems to be solved by the invention]
However, the above linear motor is still insufficient when employed in a machine tool or the like. This is because the cooling pipe is between the coils and is not in direct contact with each coil over the entire surface. Therefore, even if the conventional cooling structure is adopted as it is, sufficient cooling efficiency cannot be obtained.
[0006]
An object of the present invention is to provide a linear motor that is easy to manufacture and assemble and that can efficiently suppress the heat generation of a coil, and a method for manufacturing the same.
[0007]
[Means for Solving the Problems]
The present invention solves the above problems by the following means.
In addition, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
According to the first aspect of the present invention, a magnetic core (4a) formed on the substrate (3) at a predetermined interval, an insulating tube (5) fitted in the magnetic core, and the insulating tube are wound around A coil (6) and a cooling pipe (7) through which a coolant for cooling the coil flows. The magnetic pole core has a thickness from the base (4b) side toward the tip end side of the magnetic pole core (4a). The taper surface (4c, 4d) which becomes thin, the insulating tube has a taper surface (5c, 5d) having substantially the same inclination angle as the taper surface of the magnetic core, and the coil is formed of the insulating tube. The cooling pipe is wound around the tapered surface with a substantially uniform thickness, and the cooling pipe is fitted in a state of being in close contact with the gap portion of the adjacent coil, and the cooling pipe is provided at one end of the delivery pipe. A supply pipe (72) for supplying liquid and the other of the transfer pipe A linear motor (1), characterized in that from the end and a recovery pipe (73) for recovering the cooling fluid.
[0008]
A second aspect of the present invention is the linear motor according to the first aspect, wherein a cross-sectional area of the supply pipe and the recovery pipe is larger than a cross-sectional area of the connecting pipe.
[0009]
Invention of Claim 3 is a manufacturing method of the linear motor of any one of Claim 1 to Claim 2, Comprising: The process which forms the said cooling pipe in a cross-beam shape beforehand, and predetermined on the said board | substrate A step of forming the magnetic core with a gap between, a step of winding the coil around the insulating tube, a step of fitting the insulating tube around which the coil is wound into the magnetic core, and a gap between adjacent coils A step of fitting the transfer pipe of the cooling pipe into a part, a step of molding the magnetic core (4a) together with the coil and the cooling pipe incorporated;
Is a manufacturing method of a linear motor (1) including
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view of a linear motor according to an embodiment of the present invention. FIG. 2 is a side view showing a part of the linear motor according to the embodiment of the present invention. 3 is a cross-sectional view showing a state cut along line III-III in FIG. FIG. 4 is an enlarged side view showing a portion IV in FIG. 5A and 5B are views showing an exploded state of the linear motor according to the embodiment of the present invention. FIG. 5A is a perspective view and FIG. 5B is a cross-sectional view.
[0011]
The linear motor 1 is a device that generates a thrust for moving the moving body relative to the fixed body. The linear motor 1 includes a magnet-side linear motor (not shown) in which permanent magnets are arranged at a predetermined pitch, and a coil-side linear motor 2. In this embodiment, a linear motor in which three-phase alternating current is supplied to the coil is exemplified, and the number of coils and the number of permanent magnets are configured to be 9: 8 so as to reduce cogging.
[0012]
The coil side linear motor 2 is a device that generates a thrust for moving the magnet side linear motor relative to each other. The coil side linear motor 2 is disposed to face the magnet side linear motor with a gap. As shown in FIGS. 1 to 5, the coil side linear motor 2 includes a base plate 3, an iron core 4, an insulating cylinder 5, a coil 6, a cooling pipe 7, and a magnetic sensor 8.
[0013]
The base plate 3 is a substrate that fixes the iron core 4. The base plate 3 is a normal steel plate, and counterbore holes 3a for inserting bolts for fixing the coil side linear motor 2 are formed at both edges as shown in FIG.
[0014]
The iron core 4 is a member provided with pole teeth 4a formed on the base plate 3 at a predetermined interval. The iron core 4 is obtained by, for example, punching electromagnetic steel plates such as a thin plate-shaped silicon steel plate into a comb-teeth shape, and laminating and integrating them, and has tapped holes formed on the contact surface with the base plate 3. It is fixed and integrated on the base plate 3 by using. As shown in FIG. 4, the iron core 4 includes pole teeth 4a facing the permanent magnet of the magnet-side linear motor, and a base 4b fixed to the base plate 3, and the pole teeth from the base 4b side are provided on the side surfaces of the pole teeth 4a. Tapered surfaces 4c and 4d are formed with thickness decreasing toward the tip side of 4a. Accordingly, each pole tooth 4a has a substantially trapezoidal cross-sectional shape, and the tip side of the pole tooth 4a is formed into a tapered tooth having a slightly small thickness. In this embodiment, nine pole teeth 4a are arranged on the base 4b, and eight permanent magnets facing these pole teeth 4a are arranged. As a result, since cogging is reduced without narrowing the gap between adjacent coils 6, the pole teeth 4a can be formed in a simple shape with slightly inclined side surfaces. In this embodiment, when symmetrical taper surfaces are formed on both sides of the pole teeth 4a, it is preferable that the gradients of the taper surfaces are about 1/70 to 1/35, respectively, and only one side of the pole teeth 4a. In the case of forming a tapered surface, it is preferable to set the gradient of the tapered surface to about 1/35 to 2/35. The pole teeth 4a preferably have a uniform thickness, and preferably do not form the tapered surfaces 4c and 4d. However, as will be described later, the taper surfaces 4c, 4c, A predetermined inclination angle is formed in 4d. The tapered surfaces 4c and 4d may be formed symmetrically or asymmetrically. In this embodiment, since the tapered surfaces 4c and 4d are formed on the pole teeth 4a, the insulating cylinder 5 described in detail below can be easily inserted into the iron core 4.
[0015]
The insulating cylinder 5 is a cylindrical insulator (insulator) fitted into the iron core 4. As shown in FIGS. 4 and 5, the insulating cylinder 5 includes flange portions (ridges) 5 a and 5 b formed at the open ends, and tapered surfaces 5 c and 5 d having substantially the same inclination angles as the tapered surfaces 4 c and 4 d. It has. The insulating cylinder 5 is a thin molded product having a substantially rectangular cross-sectional shape. The insulating cylinder 5 is preferably formed of a material having a high softening temperature while electrically insulating the iron core 4 and the coil 6 such as a liquid crystal polymer resin. The insulating cylinder 5 may be integrally formed by combining a pair of two molded products (divided products) having a U-shaped cross section.
[0016]
The coil 6 is a member wound around the insulating cylinder 5. As shown in FIGS. 4 and 5, the coil 6 is wound around the tapered surfaces 5c and 5d of the insulating cylinder 5 with a substantially uniform thickness, and the outer dimensions of the coil are tapered surfaces 4c, 4d, 5c and 5d. Similarly, it is wound so as to be tapered. The coil 6 is a single-phase winding coil in which a portion wound around one iron core 4 becomes any one phase. The coil 6 is fitted into the iron core 4 together with the insulating cylinder 5 in a state of being wound around the insulating cylinder 5 with a predetermined number of turns at a high density. In this embodiment, the coil 6 can be easily wound around the tapered surfaces 5c and 5d of the insulating cylinder 5 by an automatic winding machine, and the quality can be accurately controlled to a predetermined number of turns and outer dimensions. In this embodiment, since the insulating tube 5 is fitted from the tip of the pole tooth 4a in a state where the coil 6 is wound around the insulating tube 5 in advance, it is possible to prevent the coil 6 from being damaged. Furthermore, in this embodiment, since the coil 6 is wound with high density, a reduction in thrust can be suppressed as compared with the thrust of a conventional three-phase linear motor that winds every three iron cores.
[0017]
FIG. 6 is a plan view showing a connection state of the linear motor according to the embodiment of the present invention.
For example, in the case of a three-phase AC linear motor, as shown in FIG. 6, coils 6 are wound around nine pole teeth 4a and connected. The three-phase wires U, V, and W are sequentially connected to the respective coils 6, and the U-phase, V-phase, and W-phase coils 6 are arranged in the order of U, V, W, U, V, W,. It arranges in the pole tooth 4a. The other end side of the coil 6 is connected together. The three-phase wire is coupled to the three-phase input line cable 6a and drawn out of the coil side linear motor 2, and a connector 6b connected to a motor driving device (not shown) is attached to the tip of the three-phase input line cable 6a. It has been. Of course, the protective ground line of the cable 6a is also connected to the base 4b.
[0018]
FIG. 7 is a perspective view of the cooling pipe of the linear motor according to the embodiment of the present invention. FIG. 8 is a front view of the cooling pipe of the linear motor according to the embodiment of the present invention. FIG. 9 is a rear view of the cooling pipe of the linear motor according to the embodiment of the present invention. FIG. 10 is a sectional view of the cooling pipe of the linear motor according to the embodiment of the present invention. FIG. 11 is a cross-sectional view of the connecting pipe of the linear motor according to the embodiment of the present invention. FIG. 12 is a cross-sectional view showing a state in which the connecting pipe of the linear motor according to the embodiment of the present invention is disassembled.
[0019]
The cooling pipe 7 is a pipe line through which a cooling liquid for cooling the coil 6 flows. As will be described in detail later with reference to FIGS. 7 to 10, the cooling pipe 7 includes a transfer pipe 71, a supply pipe 72, a recovery pipe 73, manifolds 74 and 75 connected thereto, a supply pipe 72 and a recovery pipe 73. And a delivery pipe 71 that communicates with each other. The material of the cooling pipe 7 may be copper or aluminum. If the cooling pipe 7 is copper, water having a large heat capacity, excellent cooling efficiency, and low cost can be used as it is as the cooling liquid. If the cooling pipe 7 is aluminum, an oily coolant is used to prevent corrosion. However, for example, when the inner peripheral surface of the cooling pipe 7 is plated with nickel or the like, water can be used as the coolant.
[0020]
The transfer pipe 71 is a pipe that is fitted in the gap between adjacent coils 6 in close contact with the coil 6. As shown in FIG. 11, the delivery pipe 71 has a substantially flat cross-sectional shape, and is formed of an aluminum extrusion molding material, or as shown in FIG. Is done. As shown in FIGS. 10 and 11, the delivery pipe 71 includes a first flow path 71a, a second flow path 71b, a partition wall 71c, and tapered surfaces 71d and 71e. As shown in FIG. 4, the first flow path 71 a is a flow path for flowing the coolant along the tip end side of the pole teeth 4 a of the iron core 4, and the second flow path 71 b is along the base 4 b side of the iron core 4. The flow path through which the coolant flows. As shown in FIG. 11, the first flow path 71a and the second flow path 71b are both substantially trapezoidal in cross-sectional shape, and their cross-sectional areas are substantially equal. Since a material having a high thermal conductivity is used, it is only necessary that the coolant flows equally in each flow path. The partition wall 71 c functions as a reinforcing member for the connecting pipe 71. In the case of a small linear motor, since the transfer pipe 71 is small, the partition wall 71c is not always necessary. The tapered surfaces 71d and 71e are portions that are in close contact with the coil 6. The tapered surfaces 71d and 71e are formed so as to increase in thickness from the base portion 4b side toward the distal end side of the pole teeth 4a, and are inclined in a direction opposite to the inclination direction of the tapered surfaces 4c, 4d, 5c, and 5d. . In this embodiment, it is preferable that the gradient of the tapered surfaces 71d and 71e is about 1/70 to 1/35.
[0021]
The supply pipe 72 is a pipe that supplies the coolant to one end of the transfer pipe 71, and the recovery pipe 73 is a pipe that recovers the coolant from the other end of the transfer pipe 71. As shown in FIG. 7, the supply pipe 72 and the recovery pipe 73 are fixedly brazed with a transfer pipe 71 at an interval between which the coil 6 can be brought into close contact therewith. As shown in FIG. 10, the supply pipe 72 and the recovery pipe 73 are formed in a substantially rectangular cross section, and the material thereof is made of aluminum or copper. As shown in FIG. 7, the supply pipe 72 and the recovery pipe 73 are connected to manifolds 74 and 75 at one end and closed at the other end. As shown in FIG. 10, the cross-sectional areas of the supply pipe 72 and the recovery pipe 73 are larger than the cross-sectional area of the transfer pipe 71, and the supply pipe 72 and the recovery pipe 73 are formed to be sufficiently thicker than the transfer pipe 71. ing. By doing so, unevenness in the amount of the coolant supplied to each delivery pipe 71 is prevented as much as possible.
[0022]
The manifold 74 shown in FIG. 7 is a columnar body that supplies the coolant to the supply pipe 72, and the manifold 75 is a columnar body that collects and recovers the coolant from the recovery pipe 73. The manifolds 74 and 75 are formed with a female screw portion (not shown) for mounting the pipe fittings 74a and 75a shown in FIG. 1, and the coolant is supplied to the supply pipe 72 through a pilot hole including the female screw portion. The coolant is recovered from the cooling pipe 73. The manifolds 74 and 75 stop at a height position where the transfer pipe 71 is in close contact between the coils 6 and are fixed by a mold resin described later.
[0023]
In the embodiment described above, it is not necessary to narrow the gap between the tips of adjacent pole teeth 4a, and the ratio of coil to magnet is such that the pole teeth 4a and the coil 6 can be formed in a simple shape. Since it is selected, the cross-sectional shape of the cooling pipe 7 can be made simple. Therefore, as shown in FIG. 7, the cooling pipe 7 is assembled in advance in the form of a cross-beam by the above-mentioned members, and the cooling pipe 7 is inserted from the tip side of the pole tooth 4 a, thereby connecting the cooling pipe 7 to the coil 6. The cooling pipe 7 can be brought into close contact with the coil 6 over the entire surface. When the cooling pipe 7 is in close contact with the coil 6, the cooling pipe 7 is positioned at a predetermined height with respect to the iron core 4, and a gap is formed between the cooling pipe 7 and the base portion 4b so that wiring can be performed. The
[0024]
The magnetic sensor 8 shown in FIG. 1 is a device that detects the relative position of the magnet side linear motor with respect to the coil side linear motor 2. The magnetic sensor 8 normally detects the relative position between the coil side and the permanent magnet array and feeds back a position detection signal when the secondary member is a three-phase linear motor having a permanent magnet array. The magnetic sensor 8 is connected to the connector 8b via the detection line 8a.
[0025]
Next, a method for manufacturing a linear motor according to an embodiment of the present invention will be described.
First, the iron core 4 is integrally fixed on the base plate 3, and the magnetic pole 4a is arranged at a predetermined interval. Next, the insulating cylinder 5 around which the coil 6 is wound is fitted into the magnetic pole core 4a. The electrical wiring of the coil 6 is wired on the base plate 3 along the gaps and side surfaces of the adjacent magnetic poles 4a and coupled to the three-phase input line. The electrical wiring at the other end of the coil 6 is short-circuited for each of the three-phase lines of the U phase, V phase, and W phase. The three-phase input line is accommodated in one three-phase input line cable 6a, drawn out to the outside, and connected to the connector 6b.
[0026]
The cooling pipe 7 in which the transfer pipe 71, the supply pipe 72, the recovery pipe 73 and the like are assembled in advance in the form of a cross-beam is fitted from the front end side of the pole teeth 4 a so that the transfer pipe 71 is fitted into the gap portion of the adjacent coil 6. Inserted. As a result, the cooling pipe 7 is mounted on the base plate 3 in a state where the coil 6 and the tapered surfaces 71d and 71e of the transfer pipe 71 are in close contact with each other. At this time, the electrical wiring is located in the gap between the base plate 3 and the cooling pipe 7, and the three-phase input line cable 6a is drawn out.
[0027]
After the mold is installed on the base plate 3 assembled as described above, and the iron core 4, the coil 6, the cooling pipe 7 and the like are accommodated in the mold, the mold 4 until the tip of the pole tooth 4a of the iron core 4 is buried. Resin is injected. In this embodiment, a thermosetting resin that exhibits excellent adhesion with a metal after reaction curing, has high electrical insulation, high mechanical strength, dimensional stability, and little deterioration of these characteristics at high temperatures. It is preferable to use an epoxy resin or the like. Next, when the iron core 4, the coil 6, the cooling pipe 7, etc. are heated in a state where they are buried in the mold resin, the mold resin increases in fluidity and spreads to every corner, and eventually reacts and hardens. For example, the epoxy resin melts and becomes fluid when it reaches about 50 ° C., penetrates into the gap between the coil 6 and the cooling pipe 7, and cures when heated to about 150 ° C. Bonded to the cooling pipe 7 and integrated. After the mold resin is cured and cooled, the upper surface of the mold resin is cut into a predetermined dimension by a milling machine or the like to be smooth. In this embodiment, in order to assemble the coil side linear motor 2 by such a process, the linear motor 1 capable of efficiently cooling the heat generated by the coil 6 can be easily mass-produced with a certain quality.
[0028]
The linear motor according to the embodiment of the present invention has the following effects.
(1) In this embodiment, the coil 6 is wound with a substantially uniform thickness around the insulating cylinder 5 having the tapered surfaces 5c and 5d having substantially the same inclination angles as the tapered surfaces 4c and 4d of the magnetic pole core 4a. The transfer pipe 71 through which the coolant flows is fitted in a state of being in close contact with the gap between adjacent coils 6. As a result, the coil 6 can be efficiently cooled without reducing the thrust of the linear motor 1. Further, in this embodiment, the cooling pipe 7 has a substantially flat cross-sectional shape and is formed in a tapered shape so that the cooling pipe 7 and the coil 6 can be contacted on substantially the entire surface. The tip of 4a is cooled more effectively, and the cooling efficiency can be improved.
[0029]
(2) In this embodiment, since the cross-sectional areas of the supply pipe 72 and the recovery pipe 73 are larger than the cross-sectional area of the transfer pipe 71, the cooling that flows through the first flow path 71a and the second flow path 71b of each transfer pipe 71 is performed. It is possible to prevent a difference in the liquid flow rate.
[0030]
The present invention is not limited to the embodiments described above, and various modifications or changes are possible, and these are also within the scope of the present invention. For example, in this embodiment, a three-phase AC synchronous linear motor has been described as an example. However, the present invention is not limited to this, and an induction type in which the moving body does not include a permanent magnet and is a mere derivative is also provided on the coil side. A configuration similar to that of the linear motor 2 can be employed. Further, in this embodiment, the case where the inside of the cooling pipe 7 is partitioned by one partition wall 71c has been described as an example, but one partition line may be formed in the cooling pipe 7 by omitting the partition wall 71c. The cooling pipe 7 may be partitioned by two or more partition walls.
[0031]
【The invention's effect】
As described above, according to the present invention, a coil is wound with a substantially uniform thickness around an insulating cylinder having a tapered surface whose inclination angle is substantially the same as that of the pole tooth iron core, so that the coolant flows. Since the pipes are fitted in close contact with the gaps between adjacent coils, heat generation of the coils can be efficiently suppressed.
In addition, since the cooling pipe 7 is formed in a cross-beam shape in advance and inserted between the coils, the cooling pipe can be easily attached.
[Brief description of the drawings]
FIG. 1 is a plan view of a linear motor according to an embodiment of the present invention.
FIG. 2 is a side view showing the linear motor according to an embodiment of the present invention with a part thereof omitted.
3 is a cross-sectional view showing a state cut along line III-III in FIG.
4 is an enlarged side view showing a portion IV in FIG. 2. FIG.
FIGS. 5A and 5B are views showing an exploded state of the linear motor according to the embodiment of the present invention, wherein FIG. 5A is a perspective view and FIG. 5B is a cross-sectional view.
FIG. 6 is a plan view showing a connection state of the linear motor according to the embodiment of the present invention.
FIG. 7 is a perspective view of a cooling pipe of the linear motor according to the embodiment of the present invention.
FIG. 8 is a front view of a cooling pipe of the linear motor according to the embodiment of the present invention.
FIG. 9 is a rear view of the cooling pipe of the linear motor according to the embodiment of the present invention.
FIG. 10 is a cross-sectional view of the cooling pipe of the linear motor according to the embodiment of the present invention.
FIG. 11 is a cross-sectional view of the connecting pipe of the linear motor according to the embodiment of the present invention.
FIG. 12 is a cross-sectional view showing a state in which the connecting pipe of the linear motor according to the embodiment of the present invention is disassembled.
[Explanation of symbols]
1 Linear motor 2 Coil side linear motor 3 Base plate (substrate)
4 Iron core 4a Polar tooth 4b Base 4c, 4d Tapered surface 5 Insulating cylinder 5c, 5d Tapered surface 6 Coil 7 Cooling pipe 71 Delivery pipe 71a First flow path 71b Second flow path 71d, 71e Tapered surface 72 Supply pipe 73 Recovery pipe

Claims (3)

A magnetic core formed at a predetermined interval on the substrate;
An insulating cylinder fitted into the magnetic core;
A coil wound around the insulating tube;
A cooling pipe through which a cooling liquid for cooling the coil flows,
The magnetic core has a tapered surface whose thickness decreases from the base side of the magnetic core toward the tip side of the magnetic core,
The insulating cylinder has a tapered surface having substantially the same inclination angle as the tapered surface of the magnetic core.
The coil is wound around the tapered surface of the insulating cylinder with a substantially uniform thickness,
The cooling pipe is
A transfer pipe fitted in a state of being in close contact with a gap between adjacent coils;
A supply pipe for supplying the coolant to one end of the transfer pipe;
A recovery pipe for recovering the coolant from the other end of the transfer pipe,
A linear motor characterized by The linear motor according to claim 1,
The cross-sectional area of the supply pipe and the recovery pipe is larger than the cross-sectional area of the transfer pipe;
A linear motor characterized by A method for manufacturing a linear motor according to any one of claims 1 to 2,
A step of forming the cooling pipe in a cross-beam shape in advance;
Forming the magnetic pole core with a predetermined interval on the substrate;
Winding the coil around the insulating cylinder;
Fitting the insulating tube around which the coil is wound into the magnetic core;
Inserting the cooling pipe into the gap between adjacent coils; and
Molding the coil and the magnetic pole with the incorporated cooling tube;
A method for manufacturing a linear motor.

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