JP3216865B2 - Linear motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor in which a permanent magnet and an armature coil (polyphase coil) are relatively moved.

[0002]

2. Description of the Related Art Conventionally, there have been provided a plurality of permanent magnets fixedly mounted on a yoke via a magnetic gap, and a multi-phase coil provided in the magnetic gap. Linear motors configured to move the permanent magnet and the polyphase coil relative to each other when supplied are well known.

[0003] The polyphase coil in the conventional linear motor is usually fixedly supported by a coil base which is a coil support member. As the material of the coil support member,
Conventionally, a non-magnetic material such as an epoxy resin or an aluminum alloy has been used. As a technique related to this, there is, for example, JP-A-61-288770.

[0004]

In a conventional linear motor, a non-magnetic material such as epoxy resin or aluminum alloy is frequently used for a coil supporting member because a field permanent magnet for forming a magnetic gap and a coil supporting member. This is because the thrust of the linear motor is kept constant by preventing a magnetic attraction force from being generated.

[0005] In particular, in the case of a linear motor using an epoxy resin for the support member of the polyphase coil, the resonance frequency (also called natural frequency) of the linear motor is reduced due to a decrease in Young's modulus which is a measure of the rigidity of the coil support member. There is a problem that the frequency falls to a practical frequency range, and mechanical vibration and noise are generated. In addition, since epoxy resin has low thermal conductivity, the heat generated from the polyphase coil generated by the application of the drive current is efficiently transferred to the coil support member, suppressing the temperature rise of the polyphase coil and reducing the initial thrust. It is difficult to maintain, and therefore, there is a problem that the reliability of the linear motor is reduced. Therefore, when using the epoxy resin for the support member of the multi-phase coil, it is necessary to arrange a cooling pipe through which a refrigerant is circulated to forcibly cool the heat generated from the multi-phase coil, In this case, there are problems that the design becomes complicated and an inexpensive linear motor cannot be provided.

On the other hand, when a non-magnetic metal plate such as an aluminum alloy is used for the coil supporting member, the Young's modulus is increased and the thermal conductivity is improved. There is a problem that an eddy current is generated by traversing the magnetic flux with the relative movement of the coil supporting member made of the body with the field permanent magnet forming the magnetic air gap, thereby reducing the thrust of the linear motor. Further, as disclosed in Japanese Patent Application Laid-Open No. 3-222670, there is a problem that the assembling work of the coil supporting member is complicated and a large number of man-hours are required.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and it is an object of the present invention to provide a support member for a polyphase coil which has a very high resonance frequency, that is, a natural frequency. Another object of the present invention is to provide a linear motor that suppresses a rise in temperature of a polyphase coil and does not cause a reduction in thrust by efficiently transferring heat generated from the polyphase coil to a coil support member. Another object of the present invention is to provide a linear motor that does not generate eddy currents that adversely affect the generation of thrust.

[0008]

In order to achieve the above object, according to a first aspect of the present invention, there are provided a plurality of permanent magnets forming a magnetic gap, and a multi-phase coil provided in a magnetic gap path. In a linear motor configured to move the multi-phase coil and the plurality of permanent magnets relatively by supplying a driving current to the multi-phase coil, the multi-phase coil has heat transfer and insulation properties. Technical means of being fixed to a coil support member made of non-magnetic ceramics, which has excellent characteristics. Further, in the second aspect of the present invention, the magnetic poles adjacent in the longitudinal direction are magnetized so that the polarities thereof are different from each other, and the magnetic poles having different polarities face each other.
A plurality of permanent magnets arranged and fixed to a pair of ferromagnetic yokes via a magnetic gap, and a polyphase coil provided in the magnetic gap path, by supplying a driving current to the polyphase coil In the linear motor configured to relatively move the permanent magnet and the multi-phase coil, the multi-phase coil is fixed to a coil support member made of nonmagnetic ceramics having excellent heat conductivity and insulation properties. The technical means that was adopted. In the first or second invention, the nonmagnetic ceramic has an electric resistivity of 10 ¹ (Ωcm) or more, a thermal conductivity of 1 (W / mK) or more, and a Young's modulus of 0.5 × 10 ^4. (Kg / mm ² ) or more. In the present invention, (the highest surface temperature of the multi-phase coil) − (the lowest surface temperature of the coil support member) ≦ 4
A linear motor having a good temperature distribution at a low temperature of 0 (° C.) can be configured. In the present invention, the non-magnetic ceramic constituting the coil supporting member is
50-97% by weight of aluminum nitride and boron nitride 3
It is preferable that the composite sintered body contains 〜50% by weight and inevitable impurities.

Further, in the third invention of the present invention,
A plurality of magnetic poles that are magnetized so that the polarities of magnetic poles adjacent in the longitudinal direction are different from each other and are fixed to a pair of fixed ferromagnetic yokes via a magnetic gap so that magnetic poles of different polarities face each other. A permanent magnet, and a polyphase coil provided in the magnetic air gap and moving along the longitudinal direction of the permanent magnet, and a drive circuit for supplying a sine wave drive current to the polyphase coil is connected. Moving coil type linear motor, the multi-phase coil has an electric resistivity of 10 ¹ (Ωcm)
A coil made of a non-magnetic ceramic having excellent thermal conductivity and insulation properties having a thermal conductivity of 1 (W / mK) or more and a Young's modulus of 0.5 × 10 ⁴ (kg / mm ² ) or more. The technical means of being fixed to the support member was adopted. In the present invention, it is preferable that the non-magnetic ceramic constituting the coil supporting member is made 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.

Further, in the fourth invention of the present invention,
A plurality of magnetic poles that are magnetized so that the polarities of magnetic poles adjacent in the longitudinal direction are different from each other and are fixed to a pair of movable ferromagnetic yokes via magnetic gaps so that magnetic poles of different polarities face each other. A permanent magnet and a multi-phase coil fixed in the magnetic air gap, and a driving circuit for supplying a sine-wave driving current to the multi-phase coil is connected to a movable magnet type linear motor. The phase coil has an electrical resistivity of 10 ¹ (Ω
cm) or more, and the thermal conductivity is 1 (W / mK) or more,
In addition, a technical means was employed in which the coil was fixed to a coil supporting member made of nonmagnetic ceramics having a Young's modulus of 0.5 × 10 ⁴ (kg / mm ² ) or more and excellent in heat conductivity and insulation. In the present invention, the non-magnetic ceramics constituting the coil supporting member is made of aluminum nitride 50 to 97
It is preferable to use a composite sintered body containing 3% to 50% by weight of boron nitride and unavoidable impurities.

Here, as the permanent magnet used in the present invention, a permanent magnet manufactured by a known manufacturing method (for example, a sintering method, a casting method, a super-quenching method, a bond magnet method, etc.) can be used. The general formula of the basic composition of these known permanent magnets is, for example, R-Fe-B type, SmCo ₅ type, Sm ₂
Co ₁₇ system, Sm-Fe-N system (R is Nd containing D, Dy
One or more of rare earth elements represented by Co, Al, Nb, Ga, Gd, F
e, one or more of known additional elements effective for magnetic properties such as Cu, Zr, Ti, Hf, Ni, and Si and one or two of unavoidable impurity elements such as O, C, H, and N The above can be contained. ) And one or more of a ferrite magnet, an alnico magnet, a Mn-Al-C-based magnet, a Mn-Al-based magnet and the like can be preferably used. Of these, Nd-Fe-B-based anisotropic sintered magnets and bonded magnets (isotropic magnets can be used, but anisotropic magnets capable of obtaining a high energy product are particularly preferred). Incidentally, since the Nd-Fe-B permanent magnet is very easily oxidized, the average film thickness on the surface is 2 to 1
It is necessary to form a known oxidation-resistant film (for example, Ni plating or the like) of about 00 μm.

Next, the ferromagnetic yoke used in the present invention comprises:
It can be manufactured using a known ferromagnetic material. For example, pure iron,
Soft iron, carbon steel (for example, SS41, SS400, S45C
etc. ), Known iron-based castings such as ferritic and martensitic magnetic stainless steels, cast iron and cast steel, known soft ferrites such as Mn-Zn-based ferrites, Fe-Ni-based alloys such as permalloy, and Fe-based alloys such as Kovar. Use one or more of a Ni-Co alloy and a bond type soft magnetic material obtained by pulverizing these known soft magnetic materials and bonding the powder with a thermoplastic resin or a thermosetting resin. it can. And carbon steel which can obtain a high magnetic flux density and is inexpensive is particularly preferable.

Next, the non-magnetic ceramic for the coil support member of the present invention has an electric resistivity at 25 ° C. and DC of 10 ¹ (Ωcm) or more and a thermal conductivity at 25 ° C. of 1 (W / mK). ) And a Young's modulus at 25 ° C. of 0.5 × 10 ⁴ (kg / mm ² ) or more is preferable. Here, these physical property values were specified at 25 ° C., based on the practical use temperature range (0 to 100 ° C.) of the linear motor, considering the temperature distribution, resonance frequency, and eddy current of the linear motor. It can be said that this is an appropriate value that can determine the suppression effect and the like. The electric resistivity, thermal conductivity and Young's modulus in the present invention are all the values at 25 ° C. described above. Examples of the non-magnetic ceramic include BN (preferably hexagonal boron nitride), AlN, T
Known nitrides such as iN, Si ₃ N ₄ , Sialon, and B ₂ O ₃ , MgO, MnO, Al ₂ O ₃ , SiO ₂ , Zn
O, TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , BaO, B
Known oxides such as eO, CaO, K ₂ O, and Si
C, TiC, ZrC, TaC, B 4 C, WC, W 2 known carbides such as C, and 2MgO · SiO _2, MgO · S
_{iO 2, CaO · SiO 3,} ZrO 2 · SiO 2, 3Al 2
_{O 3 · 2SiO 2, 2MgO ·} 2Al 2 O 3 · 5SiO 2,
Known silicates such as Li ₂ O.Al ₂ O ₃ .4SiO ₂ and Al ₂ TiO ₅ , MgAl ₂ O ₄ , Ca ₁₀ (PO ₄ )
₆ (OH) ₂ , BaTiO ₃ , Pb (Zr, Ti) O ₃ ,
One or more of a composite oxide such as (Pb, La) (Zr, Ti) O ₃ and LiNbO ₃ and a composite sintered body of AlN and BN can be used. And of these,
Composite sintered body of AlN and BN, AlN, Al ₂ O ₃ , BN
(Preferably hexagonal boron nitride), and a composite sintered body of AlN and BN is particularly preferred.

The composition of the composite sintered body of AlN and BN used in the present invention is 50 to 97% by weight (preferably 65 to 95% by weight) of aluminum nitride and 3 to 50% by weight of boron nitride.
% By weight (preferably 5 to 35% by weight), and at least one metal compound selected from metals of Group 2a and Group 3a in the periodic table of 0.01 to 10% by weight based on the mixture of aluminum nitride and boron nitride. (Preferably 0.05 to 5% by weight). Periodic Table 2a
Be, Ca, Sr, Ba, and the like are preferable as the metal of the group III. Further, as the metal consisting of group 3a of the periodic table, Y or a lanthanum group metal is preferably used, and more specifically, Y, La, Ce, Pr, Nd, Pm, S
m, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
b, Lu, etc., particularly Y, La, Ce, Nd, etc. are preferred. The metal compound comprising Group 2a or Group 3a of the periodic table is not particularly limited, and aluminum nitride powder and / or
Alternatively, the above-mentioned metal compound known as a sintering aid for boron nitride powder can be used. Generally, for example, compounds such as nitrates, carbonates, chlorides and oxides are suitably used. When a nitrate of the above metal compound is used, it is converted into nitrite by heating in an oxygen-containing gas atmosphere, but carbonate and chloride are converted into oxide. The amount of use of at least one metal compound selected from metals of Groups 2a and 3a of the Periodic Table is 0.01 to 0. It may be selected from the range of 0.05% by weight, preferably 0.05 to 4% by weight. These addition amounts may be appropriately determined in consideration of the oxygen content and the impurity content in the composite sintered body, physical properties required for the composite sintered body, and the like. In the composite sintered body of AlN and BN used in the present invention, when at least one metal compound selected from the above-mentioned Group 2a or 3a metal of the periodic table is included in the unavoidable impurities, Ca becomes 450 (ppm). ), Cr is 6
0 (ppm), Mg 15 ppm, Ni 5 (ppm)
, Fe contains less than 20 (ppm), Si contains less than 15 (ppm), and O contains about 0.5 (% by weight).

The non-magnetic ceramic of the present invention preferably has an electric resistivity of 10 ¹ (Ωcm) or more. This is because if the electric resistivity is less than 10 ¹ (Ωcm), a reduction in the thrust of the linear motor due to the eddy current generated in the coil supporting member becomes a problem. Further, the thermal conductivity is 1 (W
/ MK) or more. Thermal conductivity of 1 (W
/ MK), the heat generated from the multi-phase coil generated by the drive current cannot be efficiently conducted to the coil supporting member. As a result, the multi-phase coil portion is locally heated to a high temperature to increase the Joule heat loss. Therefore, the effective current supplied to the multi-phase coil is reduced, and the thrust is reduced. It is more preferable that the thermal conductivity is 10 (W / mK) or more. The Young's modulus is 0.5 × 10 ⁴ (kg / mm ² )
It is preferable that it is above. Young's modulus is 0.5 × 10 ⁴
If it is less than (kg / mm ² ), the resonance frequency of the coil supporting member will be reduced, which causes a problem that mechanical vibration and noise are generated during continuous operation of the linear motor. The Young's modulus is more preferably at least 1.0 × 10 ⁴ (kg / mm ² ). Next, the dielectric breakdown voltage of the non-magnetic ceramic of the present invention is a value measured under the conditions of 25 (° C.), a sample thickness of 1 (mm) and AC, and this dielectric breakdown voltage is 1 (kV /
mm) or more is preferable in order to ensure insulation.

In the present invention, when the linear motor is operated, (the maximum surface temperature of the polyphase coil)-(the minimum surface temperature of the coil supporting member) ≦ 40 ° C., preferably ≦ 30.
° C, particularly preferably ≦ 20 ° C, and a linear motor having an overall low temperature and uniform temperature distribution can be obtained. If the temperature difference exceeds 40 ° C., the thrust is reduced due to the heat generated from the polyphase coil, and the bonding portion between the polyphase coil and the coil supporting member is slightly softened. Problems such as peeling of the adhesive are likely to occur.

[0017]

According to the present invention, the multi-phase coil is fixed to a coil supporting member made of epoxy resin or an aluminum alloy by fixing the coil to a coil supporting member made of non-magnetic ceramics which is conductive and insulating. Since the Young's modulus is higher than that, the resonance frequency of the linear motor greatly exceeds the practical frequency range, so that the occurrence of mechanical vibration or the like during operation of the linear motor is prevented. Also,
Since the heat conductivity is sufficiently high, the heat generated from the multi-phase coil due to the drive current is efficiently conducted to the coil supporting member, and further, other members connected to the coil supporting member (for example, columns, etc.). Since the heat generated from the multi-phase coil is efficiently transferred to the
In the configuration of the heat-dissipation type linear motor, even if the continuous long-time operation is performed, the local high-temperature portion is not particularly formed in the polyphase coil portion, and a linear motor having a low and narrow temperature distribution can be obtained. As a result, it is possible to prevent the thrust of the linear motor from deteriorating with time. Further, the coil supporting member made of the non-magnetic ceramic of the present invention has a higher electric resistivity than a non-magnetic metal such as an aluminum alloy, and the coil supporting member moves with the relative movement with the field permanent magnet. Since the eddy current generated when crossing the magnetic flux is small, a decrease in thrust can be further suppressed.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
FIG. 1 is a sectional view showing a main part of an embodiment of a movable magnet type linear motor according to the present invention. As shown in FIG. 1, a plurality of permanent magnets 1 are arranged so that the polarities of magnetic poles adjacent in the longitudinal direction are different from each other, and a pair of ferromagnetic yokes 3 (SS
41) with an epoxy adhesive (Araldite AV138)
etc. ). The permanent magnet 1 is used for a magnetic field, and is configured such that a magnetic gap 7 is formed and polarities of different magnetic poles are opposed to each other in the thickness direction of the permanent magnet 1 via the magnetic gap 7. The permanent magnet 1 and the ferromagnetic yoke 3 constitute a mover 10 in the linear motor of FIG. 1. The permanent magnet 1 and the ferromagnetic yoke 3 are provided so as to be movable in a direction parallel to the plane of the drawing. Furthermore, the polyphase coil 2 and the coil support member 4 are arranged in a magnetic gap path 70 where a magnetic gap 7 can be formed by a pair of opposed permanent magnets 1, and the coil support member 4 is a column 5 (for example, SUS304 or the like). ), And is fixed to the base 6 (for example, SUS304 or the like) to constitute the stator 20 side. Here, the permanent magnet 1 is Nd manufactured by Hitachi Metals, Ltd.
-Fe-B based anisotropic sintered magnet: HS-37BH,
On the surface of the permanent magnet 1, a Cu plating having an average thickness of 5 μm is formed, and an average thickness of 50 μm is formed on the Cu plating.
A three-layer oxidation-resistant coating is formed by forming an Ni plating of μm and further forming an electrodeposited epoxy coat having an average thickness of 30 μm on the Ni plating. The coil supporting member 4 is made of a composite sintered body of AlN and BN (trade name: SHAPAL Msoft, manufactured by Tokuyama Corporation), and has a main component of 80% by weight of aluminum nitride and 20% by weight of boron nitride. . At the time of sintering of the composite sintered body, calcium nitrate tetrahydrate is used as at least one metal compound selected from metals of Group 2a and Group 3a of the periodic table based on 100 parts by weight of a mixture of aluminum nitride and boron nitride. 8.4 parts by weight are added as a sintering aid. The composite sintered body contains 450 ppm of Ca,
60 (ppm), Mg 15 ppm, Ni 5 (pp
m), Fe is 20 (ppm), Si is 15 (pp)
m), O (0.5% by weight) is contained as an unavoidable impurity. The coil support member 4 made of a composite sintered body of AlN and BN (Shapal Msoft) having this composition was used in Example 1.

Next, the multi-phase coil 2 is
Is fixed, and by switching the current supplied to each coil of the multi-phase coil 2 (usually using a three-phase sine wave drive current supplied from a drive circuit not shown), the permanent magnet 1 Mover 1 comprising magnetic yoke 3
0 can move in the magnetic air gap 70 along the longitudinal direction of the permanent magnet 1 by obtaining a constant thrust. The switching of the drive current of the polyphase coil 2 is performed based on a detection signal from a magnetic detection element (for example, a Hall element or the like) not shown. Thus, the ferromagnetic yoke 3 to which the permanent magnet 1 is fixed is configured to move.

Next, the multi-phase coil 2 and the coil supporting member 4
Will be described. FIG. 2 is a diagram illustrating a state in which the multi-phase coil 2 is fixed to the coil support member 4. After winding a conductor made of a Cu alloy covered with an insulator to form the multi-phase coil 2, the multi-phase coil 2 is applied to the surface of the coil support member 4 with an epoxy-based adhesive (for example, a mixture of AV138 and HV998). ). Here, Table 1 shows the main physical property values of the epoxy resin, the aluminum alloy, and the non-magnetic ceramic (Shapal Msoft) of the first embodiment, which are conventionally used as the coil supporting member 4.

[0021]

[Table 1]

From Table 1, it can be seen that the use of non-magnetic ceramic shapel Msoft for the coil support member 4 can increase the Young's modulus of the coil support member 4.
Therefore, the resonance frequency of the linear motor can be largely shifted to a higher frequency side than the frequency at the time of operation, so that mechanical vibration and the like at the time of linear motor operation can be suppressed. However, according to Table 1, when epoxy resin is used as the material of the coil support member 4, the Young's modulus becomes less than 1/10 of the shaper Msoft, and mechanical vibration during the operation of the linear motor cannot be suppressed. . In addition, even when an aluminum alloy, which is a nonmagnetic metal, is used, the Young's modulus is about 1/3 of the shaper Msoft, and the resonance frequency is also lowered, which is a problem. As described above, when the coil supporting member made of Shapepal Msoft is used, the resonance frequency is set to 3 times as compared with the case where the epoxy resin is used.
It can be about twice as high. Note that the resonance frequency (natural frequency) is proportional to the square root of the Young's modulus.

As shown in Table 1, the non-magnetic ceramic (Shapal Msoft) of Example 1 has a higher thermal conductivity than that of the epoxy resin (Comparative Example 1), and is almost the same as the aluminum alloy (Comparative Example 2). Since the heat conductivity is the same, the heat generated by the multi-phase coil generated by the drive current is easily conducted to the entire coil supporting member, and the heat generated by the multi-phase coil extends to other members connected to the coil supporting member. As a result, the temperature rise of the polyphase coil can be suppressed to a minimum.

Further, in the present invention, the purpose of using a non-magnetic ceramic such as shapel Msoft for the coil supporting member is also to prevent the generation of thrust ripple. That is, if the coil supporting member 4 is formed of a magnetic material, an imbalance due to the magnetic attraction of the permanent magnet 1 occurs on the coil supporting member 4 side, which causes thrust ripple. As shown in Table 1, the non-magnetic ceramics of Example 1 (Shapal Mso
ft) has a higher electrical resistivity than the aluminum alloy (Comparative Example 2), so that with the relative movement of the field permanent magnet,
There is an advantage that eddy current generated when the coil supporting member 4 crosses the magnetic flux is small. For this reason, a decrease in thrust due to eddy current can be suppressed.

Next, the linear motor shown in FIG. 1 of the present invention (using the coil supporting member 4 made of Shapepal Msoft shown in the first embodiment of Table 1) is driven, and is continuously driven for 10 hours by the polyphase coil 2. To supply a three-phase sine-wave drive current, immediately stop the linear motor, and
The maximum surface temperature (T ₁ ) and the minimum surface temperature (T ₂ ) of the coil supporting member 4 were measured. Here, this measurement is 25
(° C.) ambient temperature. The result is ΔT = T ₁ −T ₂
= 2 (° C) and good temperature distribution of T ₂ = 26 (° C) were obtained. This temperature difference (ΔT) is obtained when the coil supporting member 4 is made of a conventional epoxy resin (Comparative Example 1) and (T ₁ ) and (T ₂ ) are measured under the same conditions as in Example 1.
This temperature difference (ΔT) is significantly smaller than the values of T = T ₁ −T ₂ = 95 (° C.) and T ₂ = 30 (° C.), and the heat generated from the polyphase coil 2 is This proves that heat is efficiently transferred to the member 4 and the member connected to the coil supporting member 4 to achieve a uniform temperature distribution. As described above, it was confirmed that a good temperature distribution was obtained when the coil support of Example 1 was used for a linear motor.
In this case, no abnormality was observed at the bonding interface between the polyphase coil 2 and the coil supporting member 4. On the other hand, when the coil supporting member 4 is made of a conventional epoxy resin (Comparative Example 1), as described above, the non-uniform temperature distribution of ΔT = 95 (° C.) is exhibited, and the heat generated in the multiphase coil 2 is increased. Is not easily diffused into the coil supporting member 4, the bonding interface between the locally heated multi-phase coil 2 and the supporting member 4 is slightly softened, and the multi-phase coil 2 is hardened by hand. When pressed, the multi-phase coil 2 slightly moves and the position shifts easily.

FIG. 3 is a sectional view showing a main part of an embodiment of a moving coil type linear motor according to the present invention. In FIG. 3, components having the same reference numerals as those in FIG. 1 represent the same components as those in FIG. In FIG. 3, a plurality of permanent magnets 1 facing each other via a magnetic gap 7 include a pair of ferromagnetic yokes 3 (for example,
SS400 etc. ) To form the stator 20.
Further, both ends of the ferromagnetic yoke 3 are held by support members 8. A coil support member 4 (a composite sintered body of AlN and BN) in which the multi-phase coil 2 is fixed with an epoxy-based adhesive (for example, a mixture of AV138 and HV998):
Tokuyama Co., Ltd., trade name: SHAPAL MSoft, whose main component is a composition of 65% by weight of aluminum nitride and 35% by weight of boron nitride, and the content of inevitable impurities is the same as that of Example 1. This is Example 2. ) Are movably disposed in the magnetic air gap 70 along the longitudinal direction of the permanent magnet 1 as the mover 10. In the case of Example 2, the density was 2.8 (g / cm ³ ), the thermal conductivity was 75 (W / mK), and the electric resistivity was 2.6 × 10.
¹² (Ωcm), Young's modulus is 18000 (kg / mm ² )
It is.

In the linear motor of FIG. 3 using the coil support member 4 made of Shapepal Msoft of the second embodiment,
The coil supporting member 4 was excellent in rigidity, and no mechanical vibration or the like occurred. In addition, the coil support member 4 efficiently transfers heat generated from the multi-phase coil 2 to suppress a rise in the temperature of the multi-phase coil 2 and generate an eddy current that adversely affects the generation of thrust. Did not.
Then, the linear motor of FIG. 3 using the coil supporting member 4 manufactured in the second embodiment is continuously operated under the same conditions as those of the linear motor of FIG. T ₁ ) and the minimum surface temperature (T
₂ ), ΔT = T ₁ −T ₂ = 3 (° C.), T
A good value of ₂ = 26 (° C.) was obtained. Also, △ T
= 3 (° C.), the bonding interface between the polyphase coil 2 and the support member 4 was normally fixed.

In the above embodiment, the non-magnetic ceramic constituting the coil supporting member is shaped as a shapel M.
Although the case of soft (a composite sintered body of AlN and BN) has been described, the non-magnetic ceramic constituting the coil supporting member has an electrical resistivity of 10 ¹ (Ωcm) or more and a thermal conductivity of 1 (W / mK). ) Or more and the Young's modulus is 0.5 ×
Naturally, if it is 10 ⁴ (kg / mm ² ) or more, it can be effectively used in the present invention. In the present invention, the electric resistivity of the nonmagnetic ceramic is 10 ¹ (Ωcm).
More preferably, the thermal conductivity is 10 (W / mK) or more, and the Young's modulus is 1.0 × 10 ⁴ (kg / mm ² ) or more.

Table 2 shows that of the embodiment 2 and the shapel Msoft (A) which can constitute the coil supporting member of the present invention.
Physical properties of AlN (Example 3) and α-Al ₂ O ₃ (Example 4) are shown as examples of nonmagnetic ceramics other than the 1N and BN composite sintered body).

[0030]

[Table 2]

[0031]

[Table 3]

Example 3 and Comparative Example 1 were replaced with Example 1.
In the same manner as in Example 1, when ΔT (° C.) was evaluated under the same conditions as in Example 1 using the coil support member 4 of the linear motor in FIG. 1, the results shown in Table 3 were obtained. Further, ΔT (° C.) was evaluated under the same conditions as in Example 2 by using those of Example 4 and Comparative Example 2 for the coil support member 4 of the linear motor in FIG. And the results in Table 3 were obtained. According to Table 3, the electric resistivity of the non-magnetic ceramic constituting the coil supporting member 4 is 10 ¹ (Ωcm) or more, the thermal conductivity is 1 (W / mK) or more, and the Young's modulus is 0.1.
If it is 5 × 10 ⁴ (kg / mm ² ) or more, it can be seen that even when the above-described continuous operation is performed, excellent heat conductivity of ΔT (° C.) <20 (° C.) is exhibited. Also, this ΔT (° C)
Immediately before the measurement, that is, in the state where the three-phase sine wave drive current was continuously supplied to the polyphase coil 2 for 10 hours, the thrust of the linear motor was measured.
As shown in Table 3, the thrust of the sample No. 4 did not substantially change as compared with the initial thrust at the start of operation, but the thrust of the samples of Comparative Examples 1 and 2 was significantly reduced. Thus, it can be seen that the use of the coil supporting member of the present invention minimizes the reduction in thrust.

In the above-described embodiment, a pair of magnetic poles are magnetized so that the magnetic poles adjacent to each other in the longitudinal direction have different polarities, and the magnetic poles having different polarities face each other through a magnetic gap. Although an example of a linear motor including a plurality of permanent magnets arranged and fixed to a yoke has been described, the present invention is not limited to this. For example, FIG. 4 shows another embodiment of the movable magnet type linear motor of the present invention. 4, the same reference numerals as those in FIG. 1 denote the same components as those in FIG. In FIG. 4, a plurality of permanent magnets 1 are arranged and fixed to one ferromagnetic yoke 3a (SS41) so that magnetic poles adjacent in the longitudinal direction have mutually different polarities, and a magnetic gap 7 is provided.
The movable element 10 is disposed so as to face the other ferromagnetic yoke 3b (SS41) via the movable element 10. The ferromagnetic yokes 3a and 3b are connected by a holding member (not shown) to form a pair of ferromagnetic yokes. FIG.
1 has the same effect as the coil supporting member 4 of the present invention as in the case of FIG. Also,
For example, FIG. 5 shows another embodiment of the moving coil linear motor of the present invention. 5, components having the same reference numerals as those in FIG. 3 represent the same components as those in FIG. In FIG. 5, a plurality of permanent magnets 1 are disposed and fixed to one ferromagnetic yoke 3a (SS41) so that the magnetic poles adjacent to each other in the longitudinal direction have mutually different polarities, and are further fixed via a magnetic gap 7. The stator 20 is arranged so as to face one ferromagnetic yoke 3b (SS41). The operation of the coil supporting member 4 of the present invention, which is the same as that of FIG.

Next, regarding the longitudinal arrangement of the permanent magnets 1 constituting the linear motor of the present invention, for example, in FIG. 1, the permanent magnets arranged and fixed to the pair of ferromagnetic yokes 3 via the magnetic gap 7 are shown. 1 in the longitudinal direction adjacent to each other h
May be arranged. In this case, it is preferable to set the interval h in the range of 0 <h ≦ W. Here, W is the dimension of the permanent magnet 1 in the longitudinal direction. In this case, a two-phase current or the like can be used as a drive current supplied to the multiphase coil 2 in addition to a three-phase current according to a desired thrust pattern. Also in FIG. 3, each of the permanent magnets 1 arranged and fixed to the pair of ferromagnetic yokes 3 via the magnetic gap 7 may be arranged at an adjacent interval h in the longitudinal direction. In the above embodiment, the permanent magnet 1 fixed to the ferromagnetic yoke 3 is composed of a plurality of magnets. Is also good. In the above embodiment, the ferromagnetic yokes 3, 3a, 3
Although b is used, a nonmagnetic yoke (for example, SUS304 or the like) may be used instead. Further, the coil supporting member 4 in the present invention may be made of a non-magnetic ceramic having an integral structure, or may be formed by joining divided non-magnetic ceramics to a known joining means (for example, an epoxy adhesive AV1).
38 and HV998. ), And may be selected in consideration of the workability of the non-magnetic ceramic used.

[0035]

According to the present invention, the resonance frequency of the coil supporting member can be set very high, so that no mechanical vibration or the like occurs, and the heat generated from the polyphase coil is connected to the coil supporting member and the coil supporting member. Heat can be efficiently transferred to the other members, so that the temperature rise of the polyphase coil can be suppressed, and there is no eddy current that adversely affects the generation of thrust.
A highly reliable linear motor can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of a linear motor according to the present invention.

FIG. 2 is a diagram showing a configuration of a polyphase coil and a coil support member according to the present invention.

FIG. 3 is a sectional view of a main part showing another embodiment of the linear motor according to the present invention.

FIG. 4 is a sectional view of a main part showing another embodiment of the linear motor according to the present invention.

FIG. 5 is a sectional view of a main part showing another embodiment of the linear motor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Permanent magnet 2 Multi-phase coil 3, 3a, 3b Ferromagnetic yoke 4 Coil support member 5 Prop 6 Pedestal 7 Magnetic gap 8 Support member 10 Mover 20 Stator 70 Magnetic gap

Continuation of the front page (56) References JP-A-2-23057 (JP, A) JP-A-4-137383 (JP, A) JP-A-4-128085 (JP, U) JP-A-49-8711 (JP) , U) "Ceramic Engineering Handbook", edited by The Ceramic Society of Japan, published by Gihodo Publishing Co., Ltd., pages 1794-1800. Table 2.15 Table 2.18 "Fine Ceramics Handbook", Kenya Hamano, 3rd edition, June 20, 1987 Published by Asakura Shoten, pages 650-651. Table IV. 5.1 (58) Field surveyed (Int. Cl. ⁷ , DB name) H02K 41/02 H02K 41/03

Claims (1)

(57) [Claims] A plurality of permanent magnets forming a magnetic gap; and a multi-phase coil provided in the magnetic gap path.
In a linear motor configured to move a polyphase coil and a plurality of permanent magnets relatively by supplying a driving current to the polyphase coil, the polyphase coil is made of aluminum nitride.
50-97% by weight of boron and 3-50% by weight of boron nitride
A linear motor fixed to a coil support member formed of a nonmagnetic ceramic made of a composite sintered body containing manganese and unavoidable impurities .