JPH11122904A - Linear motor and manufacture of coil supporting member thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obviate machining, by kneading ceramic powder and water, injecting the kneaded material into a mold for coil supporting member molding, and, after the injected kneaded material is hardened, releasing it form the mold. SOLUTION: A model of a coil base 1 of metal or synthetic resin is made by machining prior to molding of the coil base 1. Silicone rubber is applied to the model for the purpose of making up a mold, and thus the mold for coil base manufacture is made. Then, water is added to ceramic powder in a ratio of 13:100, and the mixture is well kneaded. The kneaded material is injected into the mold for coil base manufacture and solidified. After the injected kneaded material is hardened, the hardened molding is taken out of the mold. As a result, the coil base 1 having a partition between recesses 3a, 3b is formed. A linear motor using the coil base 1 is of so-called moving-magnet type, wherein a multilayered coil is placed on the stator side, and permanent magnets are placed on the mover side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil supporting member for a linear motor, and more particularly to a technique effective when applied to a coil supporting member formed of ceramic.

[0002]

2. Description of the Related Art Conventionally, a linear motor in which a permanent magnet and an armature coil (polyphase coil) are relatively linearly movable is a type of electric motor, such as a head drive device such as a magnetic disk or an X-ray motor. It is widely used as a linear drive device such as a Y plotter.

[0003] Here, the polyphase coil of the linear motor is usually fixedly supported by a coil base, which is a coil support member, as in a linear motor disclosed in Japanese Patent Application Laid-Open No. 1-185157, for example. FIG. 5 is an explanatory diagram showing an example of a state of disposition of polyphase coils in such a conventional linear motor. In this case, the multi-phase coils 51 are fitted and fixed to coil mounting holes 53 formed in the coil base 52, respectively, as shown in FIG. Also,
A magnetic gap is provided between the permanent magnets 54a and 54b, and a magnetic circuit is formed together with the yoke 55. The multi-phase coil 51 fixed to the coil base 52 is provided in the magnetic gap.

On the other hand, a non-magnetic material such as an epoxy resin or an aluminum alloy is used for the coil base 52 in order to prevent magnetic attraction between the permanent magnets 54a and 54b. However, the coil base using epoxy resin has a low Young's modulus, so that the resonance frequency is lowered to a practical frequency range, and mechanical vibration and noise may occur. Moreover, since the epoxy resin has a low thermal conductivity, the heat generated in the multi-phase coil cannot be efficiently dissipated.

On the other hand, the coil base using an aluminum alloy does not have the above problems in Young's modulus and thermal conductivity. However, since the coil base is a conductor, there is a problem that an eddy current is generated in the coil base when crossing the magnetic flux and the thrust of the linear motor is reduced.

In order to solve these problems, in recent years, a coil base has been formed by sintering a non-magnetic ceramic having excellent heat conductivity and insulation, such as a linear motor disclosed in JP-A-8-107665. Has also been proposed. That is, the electric resistance of the coil base is 10 ^1.
(Ωcm) or higher, a thermal conductivity of 1 (W / mk) or higher, and a Young's modulus of 0.5 × 10 ⁴ (KG / mm ² ) or higher are formed of ceramic.

FIG. 6 is an explanatory diagram showing an example of a linear motor having such a configuration. In FIG. 6, the multi-phase coil 61 is fixed to a coil base 62 made of ceramic and disposed in a magnetic gap formed between the permanent magnets 63, 63b. In this case, the coil base 62 is formed of a composite sintered body containing 50 to 97% by weight of aluminum nitride, 3 to 50% by weight of boron nitride, and unavoidable impurities in order to satisfy the above conditions.

[0008]

Here, in a linear motor, the smaller the magnetic gap, the greater the thrust.
That is, if the magnetic gap can be reduced, the leakage of the magnetic flux between the magnets can be reduced, and the magnetic flux density therebetween can be increased. Accordingly, the thrust of the motor can be increased accordingly, and even when the same thrust is obtained, the amount of current and the amount of heat generated by the motor can be reduced.

Therefore, when the multi-phase coil is fixed to the coil base, it is preferable to provide the coil mounting hole 53 in the coil base 52 as shown in FIG. 5 and fix the multi-phase coil 51 there. However, in the linear motor of FIG. 6, when the concave portion for the polyphase coil 61 is to be molded in the coil base 62, there is a problem that the remaining wall thickness becomes thin and the formability is not good. Therefore, in order to form the concave portion, machining such as cutting and grinding is required for the coil base 52, and there is a problem that the manufacturing cost is increased.

An object of the present invention is to provide a method of manufacturing a coil support member for a linear motor, which can easily form a coil base having a complicated shape.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0012]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, in the method of manufacturing a coil supporting member for a linear motor according to the present invention, the permanent magnet and the polyphase coil are disposed so as to be relatively movable, and the polyphase coil is fixedly supported by the coil supporting member. A method for manufacturing a coil supporting member of a linear motor, comprising kneading ceramic powder and water, injecting the kneaded material into a mold for forming a coil supporting member, and releasing the kneaded material from the mold after curing. Thus, the coil support member is formed. As a result, a ceramic coil base having a complicated shape can be manufactured easily and at low cost.

On the other hand, a linear motor according to the present invention includes a plurality of permanent magnets forming a magnetic gap and a polyphase coil provided in the magnetic gap path, and supplies a drive current to the polyphase coil. In the linear motor configured to relatively move the polyphase coil and the plurality of permanent magnets, the polyphase coil is fixed to a coil support member formed by molding and hardening a kneaded product of ceramic powder and water. It is characterized by that.

The magnetic poles adjacent to each other in the longitudinal direction are magnetized so that the polarities thereof are different from each other, and the magnetic poles having different polarities are arranged and fixed to a pair of ferromagnetic yokes via a magnetic gap so as to face each other. A plurality of permanent magnets, and a polyphase coil provided in the magnetic air gap, and supplying a driving current to the polyphase coil so that the permanent magnet and the polyphase coil are relatively moved. Is characterized in that the multi-phase coil is fixed to a coil support member formed by molding and hardening a kneaded material of ceramic powder and water.

In the linear motor having such a configuration, the coil base can be easily formed by molding without machining, and the coil base itself is non-magnetic and excellent in insulation. Also, its thermal conductivity and rigidity are superior to conventional coil bases made of epoxy resin. Therefore, by using such a coil base, a linear motor that does not generate mechanical vibration or eddy current and can efficiently dissipate the heat generated from the multi-phase coil can be provided at low cost.

[0017]

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

(Embodiment 1) FIG. 1 is a perspective view showing an example of a coil base (coil support member) for a linear motor formed by a method according to the present invention, and FIG. AA in the case of attaching
It is sectional drawing along the line.

As shown in FIGS. 1 and 2, a coil base 1 for a linear motor according to the present invention is a coil supporting member formed in a flat rectangular parallelepiped shape, and a concave portion 3a is formed on both surfaces thereof while leaving a frame portion 2. , 3b are formed. A partition 4 is provided between the recesses 3a and 3b.
a and 3b form independent spaces in the coil base 1 respectively. Further, as shown by the broken lines in FIG. 1, the polyphase coil 5 can be fitted and fixed in the concave portions 3a and 3b. In the case of the coil base 1 shown in FIG. 1, four polyphase coils 5 can be attached.

Here, the coil base 1 is made of a non-magnetic ceramic having excellent heat conductivity and insulation as in the case of FIG. However, the coil base 1 according to the present invention is molded using ceramic powder unlike the one shown in FIG. 6, and the recesses 3a and 3b do not need to be formed by machining. That is, in the coil base 1, a castable ceramic powder (manufactured by ODEC Co., Ltd., trade name: MSZ · 15) is used.
The coil base 1 including the recesses 3a and 3b is integrally formed.

The physical properties of "MSZ-15" are as follows (catalog values). Density: 2.56 g / c
m ³ , thermal conductivity: about 4 × 10 ⁻³ cal-cm / (cm ²
-Sec- ° C), Dielectric strength: 75-100V / at 20 ° C
mil, volume resistivity: about 10 ¹¹ Ω · cm at 20 ° C.
Tensile strength: about 250 psi.

Therefore, a method of manufacturing the coil base 1 according to the present invention will be described. Here, before forming the coil base 1, first, a metal or synthetic resin model of the coil base 1 is manufactured by machining. And
Silicone rubber is applied to this model to form a mold, and a mold for manufacturing a coil base is manufactured. Next, water is added to the above-mentioned ceramic powder and kneaded well. Note that the “MS
When using “Z · 15”, water is added at a ratio of water 13 to powder 100. At the time of this kneading, it is preferable to use a vacuum degassing apparatus in order to suppress the generation of pores.

After sufficiently kneading the ceramic powder and water in this way, the kneaded material is poured into the previously manufactured mold to solidify the kneaded material. In this case, although it depends on the size and shape of the coil base 1, in the case of “MSZ · 15”, the kneaded material in the mold hardens in about 12 hours. And
After the injected kneaded material is cured, the cured molded product is removed from the mold. Thereby, the coil base 1 having the concave portions 3a and 3b is formed.

In the above-described manufacturing method, a simple method of forming a coil base by molding silicon rubber from a metal model has been described. It is a matter of course that the kneaded material may be injected into the mixture. However, when using a mold, it is desirable to use a wax type release material.

Next, a linear motor using the coil base 1 will be described. FIG. 3 is an explanatory diagram showing a configuration of a linear motor to which the coil base 1 of FIG. 1 is applied.
The linear motor of FIG. 3 is a so-called movable magnet type linear motor, and a multi-phase coil 5 is mounted on the stator A side.
Are disposed, and the permanent magnet 6 is disposed on the mover B side.

As shown in FIG. 1, in the linear motor, a plurality of permanent magnets 6 are arranged so that the magnetic poles adjacent in the longitudinal direction have mutually different polarities. The permanent magnet 6 is fixed to the ferromagnetic yoke 7 (SS41) using an epoxy-based adhesive (such as Araldite AV138). The permanent magnet 6 is for a magnetic field, and is configured such that a magnetic gap 8 is formed and magnetic poles of different magnetism face each other in the thickness direction of the permanent magnet 6 via the magnetic gap 8. The movable element B is configured to be movable in the direction of arrow X in FIG. 1 by the permanent magnet 6 and the yoke 7.

The permanent magnet 6 is made of Nd-Fe-B anisotropic sintered magnet: HS-37BH manufactured by Hitachi Metals, Ltd.
Is used. The surface of the permanent magnet 6 is provided with three oxidation-resistant films. That is, a Cu plating with an average thickness of 5 μm is formed, a Ni plating with an average thickness of 50 μm is formed on the Cu plating, and an electrodeposition epoxy coat with an average thickness of 30 μm is formed on the Ni plating. Have been.

On the other hand, a polyphase coil 5 and a coil base 1 are disposed in a magnetic gap 9 in which a magnetic gap 8 can be formed by a pair of opposed permanent magnets 6. In this case, the coil base 1 is fixed to the pedestal 11 (for example, SUS304 or the like) via the column 10 (for example, SUS304 or the like). The stator A is constituted by the coil base 1, the support 10 and the pedestal 11.

Next, a polyphase coil 5 formed by winding a conductor made of a Cu alloy covered with an insulator is formed on the coil base 1 using an epoxy adhesive (for example, a mixture of AV138 and HV998). It is fixed. That is, the polyphase coil 5 is housed and fixed in the concave portions 3a and 3b of the coil base 1 in a state shown by a broken line in FIG. In this way, the linear motor of FIG. 3 can effectively use the thickness of the coil base 1, so that the magnetic gap can be set smaller than that of FIG.

The multi-phase coil 5 constructed as described above
Each coil has a current (normally,
(A three-phase sinusoidal drive current is used). Then, by appropriately switching the current, the mover B including the permanent magnet 6 and the yoke 7 obtains a thrust and moves in the magnetic gap 9 along the arrow X direction. The switching of the drive current of the multi-phase coil 5 is performed based on a detection signal from a magnetic detection element (for example, a Hall element or the like) not shown.

As described above, according to the present invention, a ceramic coil base having a complicated shape can be manufactured easily and at low cost. That is, a coil base that is non-magnetic, has excellent insulation properties, and has better thermal conductivity and rigidity than conventional coil bases made of epoxy resin can be manufactured at low cost. Further, by using such a coil base, it is possible to provide at low cost a linear motor that does not generate mechanical vibration or eddy current and that can efficiently radiate heat generated from the multi-phase coil.

(Embodiment 2) Next, as Embodiment 2 of the present invention, a case where the coil base formed by the method according to the present invention is applied to a moving coil type linear motor will be described. FIG. 4 is an explanatory diagram showing a configuration of a moving coil type linear motor according to Embodiment 2 of the present invention. The same members as those of the linear motor in FIG. 3 are denoted by the same reference numerals, and the details are omitted.

In the linear motor of FIG. 4, the permanent magnet 6 is disposed on the stator A side, and the multi-phase coil 5 is disposed on the mover B side, contrary to the linear motor of FIG. In this case, the plurality of permanent magnets 6 facing each other via the magnetic gap 8 are fixed to the pair of ferromagnetic yokes 7 to form the stator A. Note that both ends of the yoke 7 are held by support members 21.

On the other hand, the multi-phase coil 5 is fixed to the coil base 1 with an epoxy-based adhesive to form the mover B. In the example of FIG. 4, three polyphase coils 5 are fixed to the coil base 1. The mover B is provided with a magnetic air gap 9.
The permanent magnet 6 is disposed so as to be movable along the longitudinal direction (direction of the arrow Y). Then, by appropriately switching the current supplied to the multi-phase coil 5, the mover B
Moves in the magnetic air gap 9 along the direction of the arrow Y with a thrust.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment and can be variously modified without departing from the gist of the invention. Needless to say,

For example, the size of the coil base and the number of polyphase coils fixed thereto are merely examples, and it is needless to say that the present invention is not limited to the above example. The same applies to the number of permanent magnets. Furthermore, the various materials described in the embodiments are merely examples, and ceramic powders that can be cast and satisfy predetermined physical properties may be appropriately applied to materials other than the above examples.

In the above description, the case where the invention made by the inventor is mainly applied to a coil base for a linear motor, which is a field of application, has been described. However, the present invention is not limited to this. The present invention can also be applied to a member for fixing an armature coil of a motor.

[0038]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1) A ceramic coil base having a complicated shape is machined by injecting a kneaded mixture of ceramic powder and water into a mold and removing the kneaded product from the mold after the mixture has hardened. It can be manufactured easily and at low cost. Therefore, a coil base that is non-magnetic, has excellent insulation properties, and has better thermal conductivity and rigidity than conventional coil bases made of epoxy resin can be manufactured at low cost.

(2) By using the coil base, a linear motor that does not generate mechanical vibration or eddy current and that can efficiently dissipate the heat generated from the multi-phase coil can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a coil base for a linear motor formed by a method according to the present invention.

FIG. 2 is a cross-sectional view taken along line AA when a polyphase coil is attached to the coil base of FIG.

FIG. 3 is an explanatory view showing a configuration of a movable magnet type linear motor to which the coil base of FIG. 1 is applied.

FIG. 4 is an explanatory diagram showing a configuration of a moving coil type linear motor according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing an example of an arrangement state of polyphase coils in a conventional linear motor.

FIG. 6 is an explanatory view showing an example of a conventional linear motor using a ceramic coil base.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coil base (coil support member) 2 Frame part 3a recess 3b recess 4 Partition wall 5 Multi-phase coil 6 Permanent magnet 7 Yoke 8 Magnetic gap 9 Magnetic gap path 10 Support 11 Base 21 Support member 51 Multi-phase coil 52 Coil base 53 Coil mounting Hole 54a Permanent magnet 54b Permanent magnet 55 Yoke 61 Polyphase coil 62 Coil base 63 Permanent magnet A Stator B Mover

Claims (3)

[Claims] 1. A method for manufacturing a coil supporting member of a linear motor, comprising a permanent magnet and a multi-phase coil disposed relatively movably, and the multi-phase coil fixedly supported by a coil supporting member. A kneaded ceramic powder and water, the kneaded material is poured into a mold for forming a coil support member, and after the injected kneaded material is cured, it is released from the mold. Manufacturing method of the member. 2. A system comprising: a plurality of permanent magnets forming a magnetic air gap; and a multi-phase coil provided in the magnetic air gap path.
In a linear motor configured to relatively move the multi-phase coil and the plurality of permanent magnets by supplying a driving current to the multi-phase coil, the multi-phase coil includes a ceramic powder and water. A linear motor fixed to a coil support member formed by molding and curing a kneaded material. 3. The magnetic poles adjacent to each other in the longitudinal direction are magnetized so that the polarities thereof are different from each other, and are fixed to a pair of ferromagnetic yokes via a magnetic gap so that magnetic poles having different polarities face each other. A plurality of permanent magnets, and a multi-phase coil provided in a magnetic air gap, and by supplying a drive current to the multi-phase coil, the permanent magnet and the multi-phase coil are relatively positioned. A linear motor configured to move, wherein the multi-phase coil is fixed to a coil support member formed by molding and hardening a kneaded material of ceramic powder and water.