JP2006262656A - Electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coreless type or a slotless type electric motor, with which the cost reduction is attained by decreasing to the utmost a quantity of expensive permanent magnets to be used, while maintaining the desired output characteristics. <P>SOLUTION: The length of a linear straight portion 5a at both sides of an armature coil 5 is L<SB>S</SB>, wherein the straight line portion is along Y direction intersecting perpendicularly to X direction in which the armature coil 5 and a permanent magnet 9 move relatively; the radius at an outer peripheral side of the coil at a substantially arc shaped coil end 5b is R<SB>2</SB>, wherein the coil end connects between each straight portion 5a; and a length of the permanent magnet 9 extended along the Y direction is W<SB>MAG</SB>. In these cases, the length W<SB>MAG</SB>of the permanent magnet 9 is set so that it satisfies the relation L<SB>S</SB>≤W<SB>MAG</SB>≤L<SB>S</SB>+7R<SB>2</SB>/4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coreless type or slotless type electric motor.

  A conventional linear motor includes a stator composed of a coreless armature armature coil group in which a plurality of annular armature coils are successively arranged along the traveling direction so as not to overlap each other, and a plurality of rectangular armature coils. A movable element in which magnetic poles adjacent to each other are arranged in different polarities, and the armature coil and the permanent magnet are connected to each other via a magnetic gap. The armatures are arranged so as to face each other and the armature coils of the stator are controlled to be energized sequentially so that there is a time difference, so that the mover moves linearly along the arrangement direction of the armature coils and permanent magnets. There is a thing of the structure.

In this case, in the prior art, the length W _MAG of the permanent magnet and the length L of the armature coil in the direction orthogonal to the direction in which the mover moves are equal to each other, that is, W _MAG = L. (For example, refer to Patent Document 1).

Japanese Unexamined Patent Publication No. 7-322595 (FIG. 2)

Thus, in the prior art, the length W _MAG of the permanent magnet and the length L of the armature coil in the direction orthogonal to the direction in which the mover moves are set to be the same length (W _MAG = L). Therefore, the effective linkage ratio indicating the linkage ratio between the armature coil and the magnetic flux, and the conversion efficiency to the torque or thrust due to the armature current flowing through the armature coil are not sufficiently considered. Therefore, from the viewpoint of the effective linkage rate and the efficiency of conversion to torque or thrust, permanent magnets are disposed wastefully even in a low efficiency range. For this reason, a lot of expensive permanent magnets are used. However, there is a problem that the desired motor output cannot be obtained, and conversely, when the same motor output is obtained, the cost increases.

  The present invention has been made to solve the above-described problems, and is a coreless type capable of reducing cost by reducing unnecessary use of expensive permanent magnets while maintaining a desired motor output. Another object is to provide a slotless type electric motor.

  In order to achieve the above object, the present invention includes an armature unit and a field unit, and the armature unit includes a plurality of annular armature coils arranged in sequence. The field side unit is formed by arranging a plurality of rectangular permanent magnets on a field iron core so that adjacent magnetic poles are different from each other, and the armature side unit and the field side unit Is arranged so that the armature coil and the permanent magnet face each other with a magnetic gap therebetween, and either the armature side unit or the field side unit is arranged in the arrangement direction of the armature coil and the permanent magnet. The following configuration is adopted in the motor configured to move relative to the motor.

That is, in the electric motor according to the present invention, the length of the straight straight portion on both sides of the armature coil along the direction orthogonal to the direction in which the armature coil and the permanent magnet move relative to each other is expressed as L _S. The radius of the coil outer periphery side of the substantially arc-shaped coil end portion connecting the straight portions is R ₂ , and the length of the permanent magnet extending along the direction perpendicular to the direction in which the permanent magnet and the armature coil move relative to each other. If the set to _{W MAG,} the length _{W MAG} of the permanent magnet,
_{L S ≦ W MAG ≦ L S} + 7R 2/4
It is characterized by being set to satisfy the relationship.

  According to the present invention, since the permanent magnet is disposed only in the region where the magnetic flux based on the permanent magnet is substantially effectively linked to the armature coil, the useless use of the permanent magnet is reduced compared to the conventional case. The cost can be reduced by the amount of expensive permanent magnets reduced. In addition, since the number of magnetic fluxes linked to the armature coil is almost the same as the conventional one, the same motor output as the conventional one can be maintained.

  In particular, when the present invention is applied to a direct acting motor, the attractive force between the permanent magnets facing each other is reduced by the amount of use of the permanent magnets, so even if a thin field core is used, the field side The predetermined rigidity of the unit can be obtained, and the size can be reduced.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of a rotary electric motor according to Embodiment 1 of the present invention, and FIG. 2 is a plan view showing an armature coil and a permanent magnet constituting the rotary electric motor.

  The rotary electric motor according to the first embodiment includes an armature side unit 1 and a field side unit 3 disposed inside the armature side unit 1 via a magnetic gap 2. In the first embodiment, the armature unit 1 is configured as a stator and the field unit 3 is configured as a rotor. On the contrary, the armature unit 1 may be a rotor and the field unit 3 may be a stator.

  The armature side unit 1 is integrated with a cylindrical armature fixing base 4 made of a weak magnetic material such as aluminum or plastic, and a mold resin along the circumferential direction of the inner peripheral surface of the armature fixing base 4. And a plurality of armature coils 5 that are jointly arranged. And each armature coil 5 in this Embodiment 1 is what is called a coreless type comprised by winding on the core which consists of an air core or a weak magnetic material, without using an armature core.

  The field side unit 3 includes a field iron core 8 supported by the shaft 7 and a permanent magnet 9 attached along the circumferential direction on the outer peripheral surface of the field iron core 8. In this case, the permanent magnet 9 is magnetized so that adjacent magnetic poles are different from each other. Therefore, the armature coil 5 of the armature side unit 1 and the permanent magnet 9 of the field side unit 3 are opposed to each other with the magnetic gap 2 therebetween.

  Here, when the direction in which the armature coil 5 and the permanent magnet 9 move relative to each other is designated as the X direction, and the direction perpendicular to the X direction is designated as the Y direction, the armature coil 5 has both left and right sides along the Y direction. The straight portion 5a having a linear shape and the coil end portion 5b having an upper and lower circular arc shape connecting the straight portions 5a are formed in a track shape in plan view by these 5a and 5b. .

Now, let L _{S be} the length of the straight portion 5a, R _{2 be} the radius of the coil outer periphery side of the coil end portion 5b, and W _{MAG be} the length of the permanent magnet 9 extending along the Y direction. 1, the length W _MAG of the permanent magnet 9 is
_{L S ≦ W MAG ≦ L S} + 7R 2/4 (1)
It is set to satisfy the relationship.

In particular, the length W _MAG of the permanent magnet 9 is
_{L S ≦ W MAG ≦ L S} + 3R 2/2 (2)
It is more desirable to set so as to satisfy this relationship.

  Note that the width W0 in the X direction of the permanent magnet 9 is naturally defined by the number of armature coils and the number of magnetic poles according to the required characteristics of the electric motor, and is not the subject of the present invention.

Next, the reason for setting the conditions of the expressions (1) and (2) will be described below.
In the first embodiment, paying attention to the effective linkage ratio indicating the substantial linkage ratio between the armature coil 5 and the magnetic flux, the Y direction of the permanent magnet 9 satisfying the conditions (1) and (2) is appropriate. The length W _MAG is set. For this purpose, first, as shown in FIG. 3, the coordinate system is determined by paying attention to the coil end portion 5 b on one end side of the armature coil 5. That is, when the coil end portion 5b is formed in a substantially circular arc shape, the center of the circle is placed at the origin O, the X-direction axis passing through the origin O passes through the origin O, and the track shape of the armature coil 5 An axis in the Y direction on the same plane as this plane is defined as the y axis. Then, with x = 0 as a base point, the radius on the inner peripheral side of the coil end portion 5b is R ₁ and the radius on the outer peripheral side is R ₂ . Further, the x coordinate on the inner peripheral side of the coil end portion 5b corresponding to a certain position y on the y axis is x ₁ , and the x coordinate on the outer peripheral side is x ₂ .

Local flux linkage at position y of the x ₁ and x coil end portion 5b by the _second value changes. Effective chain交率when flux armature coil 5 interlinked by the permanent magnet 9 is generally referred to as short-pitch winding factor k _P. Now, assume coreless or slotless type electric motor, and, if the respective electrical angle at the position of the inner peripheral side of the position and the outer peripheral side of the coil end portion 5b and the theta ₁ and theta _2, short-pitch winding factor k _p is given by the following equation (3).
k _P = (cos θ ₁ −cos θ ₂ ) / (θ ₂ −θ ₁ ) (3)
The expression (3) is not applicable to a so-called cored motor in which an iron core exists at the center of the armature coil 5, and can be applied only to a coreless type or slotless type electric motor.

Assuming that a function for converting the position coordinate x into an electrical angle is ξ (x), the short-pitch coefficient k _P (y) at a certain position y is expressed by the following equation (4).
k _P (y) = {cos (ξ (x ₁ )) − cos (ξ (x ₂ ))} / {ξ (x ₂ ) −ξ (x ₁ )}
(4)

FIG. 4 is a characteristic diagram showing the value of k _P (y) / k _P (0) normalized by the short-pitch coefficient k _P (0) in the case of y = 0 in relation to the position coordinate y. is there. Incidentally, in the _figure, shows a graph of two types of cases when the _R 1 ₌ R 2/4, and that the _R 1 = _2R 2/4. In either graph, in the region of _{y ≧ 3R 2/4 k P} (y) / k P (0) is decreased sharply. This indicates that the y ≧ 3R 2 _/ in ₄ regions by arranging the permanent magnets 9 flux is not interlinked almost the armature coil 5.

Thus, even if omitted permanent magnet 9 in the region of y ≧ 3R _2/4, the armature coil 5 and the number of crossing magnetic fluxes in comparison with the case where the permanent magnet 9 up to y = R ₂ is present There is no big difference. In particular, when attention is paid to the coil end portion 5b of one side of the armature coil 5, even when the permanent magnet 9 is provided only in a region from the origin O up to y = 3R _2/4, as in the prior art armature coil 5 and magnetic fluxes interlinked number as compared with the case of providing the permanent magnet 9 from the origin O up to y = R ₂ is substantially unchanged.

Therefore, considering the case where the permanent magnet 9 and the armature coil 5 are relatively displaced in the Y direction when assembling the coreless type rotary motor, the magnetic flux interlinking with the armature coil 5 is considered. limit required to reduce the length of the permanent magnet 9 without several changes substantially from the conventional case, one end side in the Y direction of the permanent magnet 9 in the y = 3R _2/4 of the coil end portion 5b until long Satoshi lead is when the length of the other side to the y = R ₂ of the coil end portion 5b. The total length W _MAG of the permanent magnet 9 at this time is
_{W MAG = L S + 3R 2} /4 + R 2 = L S + 7R 2/4
It becomes. Moreover, since it is necessary for the permanent magnet 9 to secure the length L _S of the straight portion 5a of the armature coil 5 as a minimum, this becomes the lower limit of the length W _MAG . Therefore, the length W _MAG of the permanent magnet 9 is
_{L S ≦ W MAG ≦ L S} + 7R 2/4
In other words, it is necessary to satisfy the above condition, that is, the condition of the above-described expression (1).

Further, there is no need to consider the relative displacement between the permanent magnet 9 and the armature coil 5 along the Y direction, and the permanent magnet 9 does not substantially change the number of magnetic fluxes linked to the armature coil 5. the length of the further shortened than in the case of formula (1) is a case where the Y direction of both ends of the permanent magnet 9, respectively, and a length of up to y = 3R _2/4 of the coil end portion 5b . At this time, the total length W _MAG of the permanent magnet 9 is
_{W MAG = L S + (3R} 2/4) × 2 = L S + 3R 2/2
It becomes. In addition, since the permanent magnet 9 needs to secure a minimum length L _S of the straight portion 5a of the armature coil 5, eventually, the permanent magnet 9 is in a region where the flux is interlinked with the armature coil 5. The length W _MAG of the permanent magnet 9 necessary to arrange the permanent magnet 9 only is
_{L S ≦ W MAG ≦ L S} + 3R 2/2
That is, it is necessary to satisfy the above condition, that is, the condition of the above-described formula (2).

Thus, in the first embodiment, the number of magnetic fluxes equivalent to the case where the permanent magnets 9 are arranged up to y = R ₂ as in the prior art can be secured with a smaller amount of permanent magnets 9 used. For this reason, since the usage-amount of especially expensive permanent magnet 9 can be reduced among the materials which comprise a coreless type rotary electric motor, the cost reduction of a coreless type rotary electric motor can be aimed at. In particular, if the condition of the formula (2) is satisfied, the length W _MAG of the permanent magnet 9 is made to be larger than that in the condition (1) without substantially changing the number of magnetic fluxes linked to the armature coil 5. Since it can be further shortened, the usage amount of the permanent magnet 9 can be further reduced.

Embodiment 2. FIG.
FIG. 5 is a plan view showing an armature coil and a permanent magnet constituting the rotary electric motor according to Embodiment 2 of the present invention.

Also in the second embodiment, the basic configuration of the rotary motor is the same as that of the first embodiment shown in FIG. 1, but the dimensional relationship between the armature coil 5 and the permanent magnet 9 is the same as in the first embodiment. Is different. That is, in the first embodiment, the length W _MAG of the permanent magnet 9 is set by paying attention to the effective linkage rate. In the second embodiment, the armature current flowing through the armature coil 5 and The length W _MAG of the permanent magnet 9 is set by paying attention to the conversion efficiency into torque by the field magnetic flux of the permanent magnet 9.

Now, if the radius of the inner circumference side of the coil of the coil end portion 5b and the R _1, the length W _MAG of the permanent magnet 9,
_{L S ≦ W MAG ≦ L S} + αR 1 + 3R 2/4 (5)
(However, α = 1.1 to 1.2)
It is set to satisfy the relationship.

in particular,
L _S ≦ W _MAG ≦ L _S + 2αR ₁ (6)
(However, α = 1.1 to 1.2)
It is more desirable to set so as to satisfy this relationship.

Next, the reason for setting the conditions of equations (5) and (6) will be described below.
In the second embodiment, an appropriate length W _MAG of the permanent magnet 9 satisfying the conditions (5) and (6) is set by paying attention to the torque conversion efficiency by the armature current and the field magnetic flux. . The torque T of the coreless rotary motor is given by the following equation (7).
T = P _N · φ _MAG · k _P · k _D · k _S · Γ (7)
Here, P _N is the number of pole pairs, φ _MAG is the number of magnetic fluxes based on the permanent magnet 9, k _D is the distributed winding coefficient, k _S is the skew coefficient, and Γ is the armature magnetomotive force.
In the present invention, it does not depend on the values of k _D , k _S , and φ _MAG . Therefore, Γ in the coil end portion 5b is derived thereafter.

  As is apparent from Fleming's left-hand rule, only the component in the Y direction which is vector-decomposed among the current flowing through the armature coil 5 is converted into torque. When the armature current flowing through the armature coil 5 is I, the absolute value Iy of the Y-direction component of the armature current at the coordinates (x, y) is given by the following equation (8).

  Therefore, the average value of Iy at the position y is obtained by the following equation (9).

  On the other hand, the number of turns n (y) of the armature coil 5 at the position y is expressed by the following equation (10).

That is, assuming that the current number of turns of each armature coil 5 is N, N in the region of 0 ≦ y ≦ R ₁ . Position y is as shown in equation (10) is larger region R _1, y is the number of turns N is reduced closer to the outer periphery of the coil end portion 5b increases. Naturally, when y = R ₂ , the number of turns N is zero.

  Therefore, the magnetomotive force Γ (y) of the armature coil 5 is expressed by the following equation (11).

FIG. 6 is a characteristic diagram showing the value of Γ (y) / Γ (0) normalized by the magnetomotive force Γ (0) when y = 0 in relation to the position coordinate y. Incidentally, in the _figure, shows a graph of two types of cases when the _R 1 ₌ R 2/4, and that the _R 1 = _2R 2/4.

As can be seen from FIG. 6, when the alpha = 1.1 to _1.2, the region of _{R 1 = R 2/4 y} ≧ α · if the the graphs _{R 2/4 (= αR 1} ), R in the region of ₁ = _2R 2/4 and when the graph is _{y ≧ α · 2R 2/4} (= αR 1), Γ (y) / Γ (0) is decreased sharply. That is, in any graph, Γ (y) / Γ (0) sharply decreases in the region of y ≧ αR ₁ . This indicates that even if the permanent magnet 9 is disposed in the region of y ≧ αR ₁ , the current flowing through the armature coil 5 is hardly converted into torque. That is, by placing the permanent magnet 9 in the region of y ≧ [alpha] R _1, the torque conversion efficiency means that extremely bad.

Therefore, even if the permanent magnet 9 is arranged in the region of y ≧ αR ₁ , the torque is not much different from the case where the permanent magnet 9 is provided until y = R ₂ . In particular, when attention is paid to one side of the coil end portion 5b of the armature coil 5, even in the case where the permanent magnet 9 only in the region of up to y = [alpha] R _1, as in the prior art, leading from the origin o to y = R ₂ Compared with the case where the permanent magnet 9 is provided, the torque is not substantially changed.

Therefore, considering the case where the permanent magnet 9 and the armature coil 5 are relatively displaced in the Y direction when assembling the coreless type rotary electric motor, the generated torque is substantially the same as in the conventional case. The upper limit necessary for shortening the length of the permanent magnet 9 without changing to is that one end side of the permanent magnet 9 in the Y direction is the length until y = αR ₁ of the coil end portion 5b, and the other end side is up to y = 3R _2/4 of the coil end portion 5b is when the length. The total length W _MAG of the permanent magnet 9 at this time is
_{W MAG = L S + αR 1} + 3R 2/4
It becomes. Moreover, since it is necessary for the permanent magnet 9 to secure the length L _S of the straight portion 5a of the armature coil 5 as a minimum, this becomes the lower limit of the length W _MAG . Therefore, the length W _MAG of the permanent magnet 9 is
_{L S ≦ W MAG ≦ L S} + αR 1 + 3R 2/4
In other words, it is necessary to satisfy the above condition, that is, the condition of the above-described expression (5).

Further, it is not necessary to consider the relative displacement between the permanent magnet 9 and the armature coil 5 along the Y direction, and the length of the permanent magnet 9 is expressed by the equation (5) without substantially changing the generated torque. The upper limit for further shortening the length of the permanent magnet 9 is that when both ends of the permanent magnet 9 in the Y direction reach the length y = αR ₁ of the coil end portion 5b. At this time, the total length W _MAG of the permanent magnet 9 is
W _MAG = L _S + αR ₁ × 2 = L _S + 2αR ₁
It becomes. Further, since the permanent magnet 9 needs to secure the minimum length L _S of the straight portion 5a of the armature coil 5, the permanent magnet 9 is disposed only in a region where it can be efficiently converted into torque. The length W _MAG of the permanent magnet 9 required for
L _S ≦ W _MAG ≦ L _S + 3αR ₁
That is, it is necessary to satisfy the above condition, that is, the condition of the above-described formula (6).

FIG. 7 is a characteristic diagram showing the results of examining the effective utilization rate for the torque conversion per volume of the permanent magnet 9 by changing the length W _MAG of the permanent magnet 9 in the Y direction. In this case, the horizontal axis represents the value of _W MAG -L _S, also as an effective utilization of the vertical axis, if you place the permanent magnet 9 only the straight portion 5a of the armature coil 5, namely _{(W MAG} - The effective utilization rate in the case of L _S = 0) is set to the reference value = 1.0. In addition, since the effective utilization factor is somewhat different depending on the length L _S of the straight portion 5a, three armature coils 5 having different values of L _S are shown.

As can be seen from Figure 7, in any of the _{L S, W} MAG -L _S is _(3R 2 _{/4+1.1R 1)} effective utilization rate smaller area than has become 0.9 or more. That is, the effective utilization rate is high under the condition shown by the equation (5). _{Conversely, W} MAG -L _S is _(3R 2 _{/4+1.1R 1)} is larger than the reduced deviates from the condition when the effective utilization rate of the formula (5), the length _{W MAG} of the permanent magnet 9 is an armature When the length of the coil 5 coincides with the length in the Y direction (W _MAG −L _S = 2R ₂ ), the effective utilization rate becomes the lowest.

  Thus, in this Embodiment 2, since the permanent magnet 9 is arrange | positioned only to the area | region which can be efficiently converted into a torque, the effective utilization rate for the torque conversion per volume of the permanent magnet 9 is large. In other words, this means that the volume of the permanent magnet 9 required to generate the same torque can be reduced. Therefore, the amount of the permanent magnet 9 used can be further reduced as compared with the case of the first embodiment. Thus, the cost of the coreless rotary motor can be reduced. In particular, if the condition of the expression (6) is satisfied, the length of the permanent magnet 9 can be made shorter than that of the condition of the expression (5) without substantially changing the generated torque. The amount used can be further reduced.

Embodiment 3 FIG.
FIG. 8 is a plan view showing an armature coil and a permanent magnet constituting the rotary electric motor according to the third embodiment.

  In the first and second embodiments, the coil end portions 5b at both ends in the Y direction of the armature coil 5 are formed in a semicircular arc shape. In the third embodiment, a straight line is formed at the center of the coil end portion 5b. A shaped portion 5c is formed.

In such a configuration, the linear portion 5c of the coil end portion 5b does not generate torque according to Fleming's left-hand rule. Therefore, it is preferable that the linear portion 5c of the coil end portion 5b is as short as possible. However, even if the linear portion 5c of the coil end portion 5b exists, the conditions of the expressions (1) and (2) or the expressions (5) and (6) are satisfied as in the first and second embodiments. If the length W _MAG of the permanent magnet 9 is set as described above, the permanent magnet 9 can be disposed only in an area where the permanent magnet 9 can be effectively used. Therefore, a coreless rotary electric motor can be configured at a low cost.

Embodiment 4 FIG.
The basic configuration of the rotary motor in the fourth embodiment is the same as that of the first embodiment shown in FIG. However, in the first embodiment, the armature coils 5 are integrally joined and arranged along the inner peripheral surface of the cylindrical armature fixing base 4 made of a weak magnetic material such as aluminum or plastic using a mold resin or the like. In contrast to the coreless type, the fourth embodiment uses a cylindrical armature core made of a ferromagnetic material instead of using the armature fixing base 4 made of a weak magnetic material. A slotless rotary electric motor is constructed by joining and arranging armature coils 5 wound around a hollow core made of an air core or a weak magnetic material along the inner peripheral surface.

Even in the slotless type rotary electric motor having such a configuration, the expression of the short-pitch winding coefficient shown in the above-described expression (3) can be applied. Therefore, in the case of the fourth embodiment, as in the first to third embodiments, the Y of the permanent magnet 9 is set so as to satisfy the conditions of the expressions (1) and (2) or the expressions (5) and (6). By setting the length W _{MAG in the} direction, the permanent magnet 9 can be arranged only in an area where it can be used effectively. For this reason, a slotless type rotary electric motor can be obtained at low cost.

Embodiment 5. FIG.
FIG. 9 is a perspective view showing a direct acting motor according to Embodiment 5 of the present invention, and FIG. 10 is a cross-sectional view taken along the line AA in FIG.

  The direct acting motor according to the fifth embodiment includes an armature side unit 1 and a field side unit 3 arranged via a magnetic gap 2 so as to sandwich the armature side unit 1 vertically. In the fifth embodiment, the armature side unit 1 is formed so that the field side unit 3 is longer in the traveling direction (X direction) than the armature side unit 1. The mover and field side unit 3 are configured as a stator. In contrast, the armature unit 1 is formed so that the length in the traveling direction is longer than that of the field unit 3, so that the armature unit 1 is fixed to the stator and field. The side unit 3 may be configured as a mover.

  The armature side unit 1 is integrally formed by using an armature fixing base 4 made of a weak magnetic material such as aluminum or plastic, and a mold resin 11 along the traveling direction (X direction) of the armature fixing base 4. The armature coils 5 are joined to each other, and the armature coils 5 are connected to each other by lead wires 12.

  And each armature coil 5 of this Embodiment 5 is what is called a coreless type wound around the core which consists of an air core or a weak magnetic material, without using an armature core, Comprising: As shown in the figure, the entire straight portion 5a formed on the left and right sides along the Y direction and the upper and lower substantially arc-shaped coil end portions 5b connecting the straight portions 5a are formed in a track shape in plan view. Has been.

  The field side unit 3 includes a field iron core 8 having a U-shaped cross section and a large number of permanent magnets 9 arranged and fixed along the X direction on the upper and lower opposing surfaces of the field core 8. In this case, the permanent magnet 9 is magnetized so that adjacent magnetic poles are different from each other. Therefore, the armature coil 5 of the armature side unit 1 and the permanent magnet 9 of the field side unit 3 are opposed to each other with the magnetic gap 2 therebetween.

In the case of the rotary electric motors shown in the first to fourth embodiments, the torque equation shown in the equation (7) can be applied. However, since the fifth embodiment is a direct acting motor, the following thrust equation ( 12).
T = (π / τ) · φ _MAG · k _P · k _D · k _S · Γ (12)
Here, π is the circumference ratio, and τ is the distance between adjacent permanent magnets 9.

However, even in the case of the fifth embodiment, there is no change in the equations shown in the equations (8) to (11). Therefore, as in the first to fourth embodiments, the length W _MAG in the Y direction of the permanent magnet 9 is set so as to satisfy the conditions of the expressions (1) and (2) or the expressions (5) and (6). Thus, the permanent magnet 9 can be disposed only in an area where the permanent magnet 9 can be effectively used as a thrust. For this reason, a coreless type direct acting motor can be obtained at low cost.

  Further, in the case of the direct acting motor according to the fifth embodiment, since the permanent magnets 9 are fixed to the upper and lower opposing surfaces of the U-shaped field core 8 constituting the field side unit 3, The permanent magnets 9 facing each other generate a force that attracts each other. For this reason, conventionally, in order to withstand this attractive force and maintain the shape, the field core 8 is thickened to obtain a predetermined rigidity.

  On the other hand, in the fifth embodiment, the amount of the permanent magnet 9 used can be reduced, and accordingly, the attractive force of the permanent magnet 9 is also reduced. As a result, the field iron core 8 that supports the permanent magnet 9 is reduced. Even if the thickness is reduced, a predetermined rigidity can be obtained. For this reason, a coreless type direct acting motor can be reduced in size.

  Further, when the armature unit 1 is a mover and the field unit 3 is a stator as in the fifth embodiment, the armature unit 1 moves a predetermined distance to the field unit 3. Since it is necessary to arrange as many permanent magnets 9 as possible, the effect of reducing the amount of permanent magnets 9 used is particularly great.

Embodiment 6 FIG.
FIG. 11 is a cross-sectional view showing a direct acting motor according to Embodiment 6 of the present invention.

  The direct acting motor of the fifth embodiment is a coreless direct acting motor in which the armature coil 5 of the armature side unit 1 does not have an armature core, but in the sixth embodiment, the armature coil 5 is used. Is divided into a plurality of stages (two stages in this example) in the thickness direction, and an armature core 13 is inserted between the armature coils 5 to constitute a slotless type direct acting motor.

Even in the slotless type rotary electric motor having such a configuration, the expression of the short-pitch winding coefficient shown in the above-described expression (3) can be applied. Therefore, in the case of the sixth embodiment, similarly to the fifth embodiment, the permanent magnet 9 is arranged in the Y direction so as to satisfy the conditions of the expressions (1) and (2) or the expressions (5) and (6). By setting the length W _MAG , the permanent magnet 9 can be arranged only in an area where it can be effectively used as a thrust. Therefore, it is possible to obtain a slotless direct acting motor at a low cost. Moreover, since the predetermined rigidity can be obtained even if the thickness of the field core 8 that supports the permanent magnet 9 is reduced, the slotless type direct acting motor can be reduced in size.

  When the armature side unit 1 is a mover and the field side unit 3 is a stator, the field side unit 3 is provided with a large number of permanent magnets 9 that only move the armature side unit 1 by a predetermined distance. Since it is necessary to arrange them, the effect of reducing the usage amount of the permanent magnet 9 is particularly great.

  The following modifications and application examples can be further considered for the first to sixth embodiments.

  In said Embodiment 1-6, although the armature coil 5 which comprises the armature side unit 1, and the permanent magnet 9 which comprises the field side unit 3 are arrange | positioned along the Y direction, armature side One of the armature coil 5 constituting the unit 1 and the permanent magnet 9 constituting the field side unit 3 or both of them may be inclined at a predetermined angle with respect to the Y direction. With such a configuration, there is an advantage that torque pulsation can be reduced in the rotary electric motor, and thrust pulsation can be reduced in the direct acting electric motor.

  In the above first to sixth embodiments, the permanent magnet 9 is in contact with the magnetic gap 2, but the permanent magnet 9 may be covered with a nonmagnetic material such as a mold resin or a SUS material. According to this configuration, there is an advantage that the expensive permanent magnet 9 can be protected.

  In the first to sixth embodiments, the permanent magnet 9 is exposed on the field core 8. However, the permanent magnet 9 may be embedded in the field core 8. According to this configuration, the expensive permanent magnet 9 can be protected, and the reluctance torque or the reluctance thrust can be obtained by performing the field weakening control, so that the torque can be increased or increased.

  In the above-described first to fourth embodiments, the case where the field side unit 3 is inside the armature side unit 1 has been described. However, the present invention is also applicable to the case where the field side unit 3 is outside the armature side unit 11. The invention can be applied. In the first to sixth embodiments, the case of a three-phase motor has been described. However, the present invention is not limited to this and can be applied to any number of phases of motor. Furthermore, the present invention can be applied regardless of the ratio between the number of magnetic poles of the permanent magnet 9 and the number of armature coils 5.

It is sectional drawing of the rotary electric motor in Embodiment 1 of this invention. It is a top view which shows the armature coil and permanent magnet which comprise the rotary electric motor. It is the figure which defined the coordinate system for demonstrating this invention. The value of the normalized short-pitch winding factor was _{k P (y) / k P} (0), it is a characteristic diagram showing the relationship between the position coordinates y. It is a top view which shows the armature coil and permanent magnet which comprise the rotary electric motor in Embodiment 2 of this invention. It is the characteristic view which showed the value of (GAMMA) (y) / (GAMMA) (0) which normalized the magnetomotive force in relation to the position coordinate y. It is a characteristic figure which shows the result of having investigated the effective utilization factor for the torque conversion per volume of a permanent magnet with the change of the length of a permanent magnet. It is a top view which shows the armature coil and permanent magnet which comprise the rotary electric motor in Embodiment 3 of this invention. It is a perspective view which shows the linear motor in Embodiment 5 of this invention. It is sectional drawing which follows the AA line in FIG. It is sectional drawing which shows the direct acting motor in Embodiment 6 of this invention.

Explanation of symbols

1 armature side unit, 2 magnetic gap, 3 field side unit, 4 armature fixing base,
5 armature coil, 5a straight part, 5b coil end part, 8 field iron core,
9 Permanent magnet.

Claims (6)

An armature side unit and a field side unit, wherein the armature side unit is formed by sequentially arranging a plurality of annular armature coils, and the field side unit is disposed on the field iron core. A plurality of rectangular permanent magnets are arranged so that adjacent magnetic poles are different from each other, and the armature side unit and the field side unit are connected to the armature coil via a magnetic gap. The permanent magnets are arranged so as to face each other, and one of the armature side unit and the field side unit is configured to relatively move along the arrangement direction of the armature coils and the permanent magnets. In the electric motor,
The length of the straight straight portion on both sides of the armature coil along the direction orthogonal to the direction in which the armature coil and the permanent magnet move relative to each other is L _S , and a substantially arc shape connecting the straight portions. In the case where the radius of the armature coil outer peripheral side in the coil end portion that is made R ₂ , and the length of the permanent magnet extending along the direction orthogonal to the direction in which the permanent magnet and the armature coil move relative to each other is W _MAG , The length W _{MAG of the} permanent magnet is
_{L S ≦ W MAG ≦ L S} + 7R 2/4
An electric motor characterized by being set so as to satisfy the relationship. The length W _{MAG of the} permanent magnet is
_{L S ≦ W MAG ≦ L S} + 3R 2/2
The electric motor according to claim 1, wherein the electric motor is set so as to satisfy the relationship. The radius of the inner circumference side of the coil of the coil end portion when the R _1, the length W _MAG of the permanent magnet,
_{L S ≦ W MAG ≦ L S} + αR 1 + 3R 2/4
(However, α = 1.1 to 1.2)
The electric motor according to claim 1, wherein the electric motor is set so as to satisfy the relationship. The radius of the inner circumference side of the coil of the coil end portion when the R _1, the length W _MAG of the permanent magnet,
L _S ≦ W _MAG ≦ L _S + 2αR ₁
(However, α = 1.1 to 1.2)
The electric motor according to claim 1, wherein the electric motor is set so as to satisfy the relationship. Either one of the armature side unit and the field side unit is configured to rotate along the arrangement direction of the armature coil and the permanent magnet. The electric motor according to item 1. 5. The armature-side unit or the field-side unit is configured to move linearly along the arrangement direction of the armature coil and permanent magnet. The electric motor according to any one of the above.

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