JP5419478B2 - motor - Google Patents

Description

  The present invention relates to a motor having an axial gap structure in which a rotor and a stator are arranged to face each other in the axial direction of a motor shaft, and more particularly to a reduction in size and weight of the motor.

  When a conventional motor having an axial gap structure is provided with one rotor and one stator, each of the rotor magnetic pole and the stator magnetic pole is disposed in the circumferential direction on the end face side where the rotor and the stator face each other. At this time, the rotor magnetic poles are formed by salient poles or permanent magnets provided in the circumferential direction on the yoke of the rotor. The stator magnetic poles are formed by teeth (saliency poles) of each phase arranged in the circumferential direction on the yoke of the stator. It is excited to the N pole and S pole while moving in the direction. Then, due to the magnetic action of the stator magnetic pole and the rotor magnetic pole, the rotor rotates and the motor shaft rotates (see, for example, Patent Documents 1 and 2).

JP 2005-151725 A JP 2008-245363 A

  In the case of a conventional axial gap structure motor, the stator facing the rotor is formed as shown in FIG. 19, for example, and a plurality of circumferentially arranged surfaces 101 a facing the rotor of the soft magnetic disk-shaped yoke 101 of the stator 100. (12 pieces in the case of 12 poles in the figure) teeth 102 are arranged.

  When a coil (not shown) wound around each tooth 102 is energized in phase order, in the case of three-phase driving of A, B, and C, the same phase (as shown in FIG. In this case, four teeth 102 (phase A) form N, S, N, and S stator poles in the counterclockwise direction of the figure. The coil energization of each tooth 102 is switched to A phase energization, B phase energization, and C phase energization every 120 degrees of electrical angle. For example, when switching from the A phase energization to the B phase energization, The coils of the four B-phase teeth 102 adjacent to each of the four A-phase teeth 102 that have been energized are energized, and the four B-phase teeth 102 are N-pole, S-pole, N-pole, S A pole stator pole is formed.

  In this case, the magnetic flux emitted from the N pole of the stator 100 returns to the S pole of the stator 100 through the S and N poles of the opposing rotor, and the magnetic flux is shown in FIG. In addition, since the yoke 101 is turned from the south pole tooth 102 to the in-phase north pole tooth 102 by turning around the yoke 101 in the circumferential direction, the magnetic flux passing through the yoke 101 is large, in other words, the thickness of the yoke 101, in other words, the stator 100 The thickness of the motor in the axial direction of the motor must be made considerably thick so as not to cause magnetic saturation, and the motor becomes thicker in the axial direction, and the motor becomes larger and its mass increases.

  When this type of axial gap structure motor is used for a drive motor of an electric vehicle or the like, two sets of a rotor and a stator are prepared and arranged in the motor axial direction in order to increase motor output (torque increase, etc.). As shown in FIG. 20, between the two rotors, two stators 100 may be arranged so-called back-to-back, and equivalently, a single stator may be disposed between the two rotors. In this case, the magnetic flux generated from the N poles of the two rotors is rotated about 1/4 in the circumferential direction from the teeth 102 of the S poles of the two stators 100 to the yoke 101 as indicated by broken arrows in the figure. Thus, the magnetic flux passes through the yokes 101 of the two stators 100 because the magnetic flux passes through the teeth 102 of the N poles and returns to the S poles of the two rotors. Not thin, the motor is large in size and become thicker in the axial direction, there is a mass also increases the problem. It should be noted that by adding such a combined structure of the rotor and the stator 100 in series, it is possible to make a 4-stage series, a 6-stage series,... The influence of the axial thickness on the size and weight of the is increased.

  The present invention provides a motor having an axial gap structure in which the axial thickness of the motor is dramatically reduced by reducing the thickness of the motor in the axial direction, thereby reducing the size (thinning) and weight of the motor. It is an object to provide a motor that is not present.

In order to achieve the above-described object, the motor of the present invention is an axial gap structure motor in which two motors arranged in the axial direction of the motor shaft and a central hole arranged between the two rotors are arranged on the motor shaft. One stator that penetrates, and a magnetic path forming member that is connected to the two rotors through the central hole and forms a magnetic path between the two rotors, the rotors having end faces facing the stator A plurality of rotor magnetic poles are arranged in the circumferential direction, and the stator has a plurality of stator magnetic poles in the circumferential direction that are excited by one magnetic pole property on one end face side facing either one of the rotors. A plurality of stator magnetic poles arranged on the other end face opposite to the other of the rotors and excited by the other magnetic pole are shifted from each stator pole on the one end face in the circumferential direction. Has been It is, magnetic flux from the rotor magnetic pole of one of said rotor, said one end face of the stator poles the other end face of the stator magnetic poles then shifted in the circumferential direction, of the stator, the rotor poles of the other of said rotor And returning to the rotor magnetic pole of the one rotor through the magnetic path forming member (claim 1).

  The motor according to the present invention further includes a field coil that generates a field in a direction for exciting the stator magnetic poles on both end surfaces of the stator in a gap between the stator in the center hole and the magnetic path forming member. It is characterized by being arranged (Claim 2).

  Furthermore, the motor of the present invention is characterized in that the magnetic pole surfaces of the rotor magnetic poles of the two rotors and the stator magnetic poles of the stator are formed on an uneven surface.

  In the case of the motor according to the first aspect of the present invention, since the stator magnetic poles are formed on both end faces of one stator, the configuration corresponding to the back-to-back of the two stators is covered by one stator. Further, all the stator magnetic poles on one end face side of the stator are excited to, for example, the S pole, and all the stator magnetic poles on the other end face side of the stator are excited to the N pole. In addition, the stator magnetic poles on both end surfaces of the stator are displaced in the circumferential direction, and when viewed from the motor shaft, the stator has an N-pole stator magnetic pole on the other end surface located between the S-pole stator magnetic poles on the other end surface side. This is equivalent to a case where the number of magnetic poles of the entire stator is doubled. For example, the magnetic flux generated from the N-pole rotor magnetic pole of one rotor is composed of the S-pole on one end face side of the stator, the N-pole on the other end face side shifted in the circumferential direction, the S-pole of the other rotor, It passes through a three-dimensional magnetic path that returns to the north pole of one rotor through the path forming member. In this case, the magnetic flux passes through the stator yoke in one direction, and the circumferential magnetic path becomes shorter as the number of magnetic poles increases, and in other words, the number of magnetic fluxes passing through the stator yoke, in other words, the magnetic path cross-sectional area of the yoke. The axial thickness of the stator can be drastically reduced, and the axial gap structure motor can be made smaller (thinner) and lighter than before. A motor having an axial gap structure can be provided.

  In the case of the motor according to the second aspect of the present invention, the stator magnetic poles on both end surfaces of the stator are also excited by the field of the field coil, so that the motor torque increases. And since a field coil is provided using the clearance gap between the stator of the center hole of a stator, and a magnetic path formation member, a motor does not enlarge by a field coil. Therefore, the output of the motor can be further increased without increasing the size.

  In the case of the motor according to the third aspect of the present invention, since the magnetic pole surfaces of the rotor magnetic poles of both rotors and the stator magnetic poles of the stator are formed on the concavo-convex surface, the opposing magnetic pole surfaces of the rotor and the stator are further widened, The motor torque can be further increased, and the motor output can be further increased.

It is an exploded perspective view which omitted a part of motor of a 1st embodiment. It is the front view and side view of the assembled state of the motor of FIG. It is a perspective view of the stator of FIG. It is explanatory drawing of the magnetic pole of the stator of FIG. It is explanatory drawing of each teeth of FIG. It is explanatory drawing of the magnetic path of the stator of FIG. It is explanatory drawing of the dimension relationship of the yoke and magnetic pole of the stator of FIG. It is explanatory drawing of the coil winding of each teeth of the stator of FIG. It is a perspective view of the rotor of FIG. It is explanatory drawing of the dimension relationship of the yoke and magnetic pole of the rotor of FIG. It is a side view of the state which assembled the motor of 2nd Embodiment. It is explanatory drawing of the magnetization characteristic by the field of the motor of FIG. It is explanatory drawing of the current-off characteristic by the field of the motor of FIG. It is a side view of the assembled state of an example of the motor of a 3rd embodiment. It is a side view of the assembled state of the other example of the motor of 3rd Embodiment. It is a perspective view of the other example of the stator of this invention. It is a perspective view of the other example of the rotor of this invention. It is sectional drawing of the multistage structure of the motor of this invention. It is a perspective view of the stator of a prior art example. It is a perspective view of the modification of the stator of a prior art example.

  Next, in order to describe the present invention in more detail, embodiments will be described in detail with reference to FIGS. In these drawings, the motor shaft and the like are omitted as appropriate.

(First embodiment)
A first embodiment will be described with reference to FIGS.

  1 is an exploded perspective view showing a schematic configuration of a motor 1A of the present embodiment, FIG. 2 shows an assembled state of the motor 1A, (a) is an end view seen from the direction of the motor shaft 2, b) is a side view along the motor shaft 2. The motor shaft 2 extends to the left side of FIGS. 1 and 2 (b), and an output (rotational power) is taken out.

  FIG. 3 is an enlarged perspective view of the stator 4 between the rotors 3a and 3b. 4A and 4B show the magnetic poles of the stator. FIG. 4A shows the magnetic poles seen from the DD line in FIG. 2B, and FIG. 4B shows the magnetic poles seen from the EE line in FIG. . FIG. 5 is an explanatory view of the teeth 71 of the stator 4, (a) is a sectional view in the circumferential direction, and (b) is a plan view of the teeth 71 as viewed from above. FIG. 6 is an explanatory diagram of the magnetic path of the stator 4. FIG. 7 is an explanatory diagram of the dimensional relationship between the yoke 41 of the stator 4 and the stator magnetic poles 7a and 7b. FIG. 8 is an explanatory diagram of coil winding of each tooth of the stator 4. FIG. 9 is an exploded perspective view of the rotors 3a and 3b. 10A and 10B are explanatory views of the dimensional relationship between the yoke 31 of the rotors 3a and 3b and the rotor magnetic pole 6. FIG. 10A shows a case where the rotor magnetic pole 6 is short, and FIG. 10B shows a case where the rotor magnetic pole 6 is long.

[overall structure]
A motor 1A having an axial gap structure according to the present embodiment is generally configured as shown in FIGS. 1 and 2, and a disk-shaped yoke 31 of two rotors (rotor cores) 3a and 3b is formed on the motor shaft 2 in FIG. Axis is attached in order from the output side. The motor shaft 2 has small, large, and medium diameters in consideration of the diameter of the tip portion ahead of the rotor 3b, the portion between the rotors 3b and 3a, and the portion after the rotor 3a. One stator (stator core) 4 is disposed between the rotors 3a and 3b. The stator 4 has a disk-shaped yoke 41, and the motor shaft 2 passes through a large diameter central hole 42 of the yoke 41 in a loosely inserted state. The cylindrical magnetic path forming member 5 passes through the center hole 42 while being mounted on the motor shaft 2, and both end surfaces of the magnetic path forming member 5 abut against the opposing end surfaces 31 a and 31 b of the yoke 31 of the rotors 3 a and 3 b. In contact with each other, the magnetic path forming member 5 is connected to the rotors 3a and 3b to form a magnetic path between the rotors 3a and 3b. The yokes 31 and 41 are made of a soft magnetic material. In addition, a solid line m in FIG. 1 indicates a motor shaft, and a broken line arrow indicates a magnetic path through which a magnetic flux passes.

  Further, in the rotors 3a and 3b, for example, eight rotor magnetic poles 6 are arranged on the end surfaces 31a and 31b facing the stator 4 at equal intervals in the circumferential direction. As shown in FIG. 4B, the stator 4 has twelve stator magnetic poles 7a excited at, for example, the S pole (one magnetic polarity) on one end face 41a facing the rotor 3a at equal intervals in the circumferential direction. As shown in FIG. 4 (a), twelve stator magnetic poles 7b that are excited, for example, to the N pole (the other magnetic pole) on the side of the other end face 41b facing the rotor 3b, surround the stator magnetic poles 7a. They are arranged at equal intervals by shifting in the direction.

  The motor 1A is driven by three-phase driving so that the coils 8 in FIGS. 4A and 4B, which are concentratedly wound around the stator magnetic poles 7a and 7b of the stator 4, are A phase, B phase, C Excited and driven in phase order.

  In this case, the stator 4 has a configuration in which the stator magnetic poles 7a and 7b on both end surfaces 41a and 41b are connected by the yoke 41, and the motor 1A includes the stator 4 and two rotors 3a disposed on both end surfaces in the axial direction. 3b and the magnetic path forming member 5 that forms the magnetic path in the axial direction of the rotors 3a and 3b form a three-dimensional magnetic path in which the magnetic flux advances in the axial direction and the circumferential direction, as indicated by the dashed arrows in FIG. . In this case, since the stator magnetic pole 7a on the end face 41a side of the stator 4 and the stator magnetic pole 7b on the end face 41b side are arranged shifted in the circumferential direction, the thickness of the yoke 41 can be reduced by dispersing the magnetic flux. .

  Next, the stator 4 and the rotors 3a and 3b will be described in further detail.

[Configuration of Stator 4]
(1) As shown in the enlarged perspective view of FIG. 3, the stator 4 has twelve stator magnetic poles 7a arranged at equal intervals of 30 degrees in the circumferential direction on one end face 41a facing the rotor 3a. Twelve stator magnetic poles 7b are disposed on the side of the other end face 41b facing 3b at an equal interval of 30 degrees, shifted by 45 degrees in the circumferential direction from each stator magnetic pole 7a. The stator magnetic poles 7 a and 7 b are magnetically connected by a yoke 41. In this case, when the stator 4 is viewed from the motor axial direction, the stator magnetic pole 7b is located between the stator magnetic poles 7a, and the motor 1A is equivalent to the state in which the number of magnetic poles of the stator 4 is doubled to 24.

  (2) Each stator magnetic pole 7a, 7b is formed by concentrating the coil 8 around the teeth 71 as shown in FIGS. The excitation directions of the respective coils 8 are directions in which all of the stator magnetic poles 7a are excited to, for example, the S pole of FIG. 4A, and all of the stator magnetic poles 7b are excited to, for example, the opposite N pole of FIG. Direction. In FIG. 4B, θ represents the amount of displacement of the positions of the stator magnetic poles 7a and 7b.

  When the four A-phase stator magnetic poles 7a and 7b arranged at intervals of 90 degrees are energized and excited in the period of the first electrical angle of 120 degrees by the three-phase drive, the next electrical angle of 120 degrees During this period, the four B-phase stator magnetic poles 7a and 7b, which are arranged adjacent to the A-phase stator magnetic poles 7a and 7b and are spaced at 90 ° intervals, are energized and excited, and the next electric angle of 120 ° is obtained. During the period, the four C-phase stator magnetic poles 7a and 7b, which are arranged next to the B-phase stator magnetic poles 7a and 7b and are spaced 90 degrees apart, are energized and excited. At this time, the magnetic flux exits from the N-pole stator magnetic pole 7b and passes through the rotor magnetic pole 6 of the rotor 3b, the magnetic path forming member 5, and the rotor magnetic pole 6 of the rotor 3a as shown by the broken line arrow in FIG. The stator 4 enters the magnetic pole 7a. In the stator 4, as shown by the broken line arrow in FIG. 3, the end face 41a side of the yoke 41 is turned from the S pole stator magnetic pole 7a by 1/8 turn (45 degrees), and the corresponding on the end face 41b side. To the N-pole stator pole 7b.

  (3) In order to improve the holding state of the coil 8, each stator magnetic pole 7a, 7b is formed with a flange 72 at the head that is wider in the circumferential direction than the teeth 71 as shown in FIG. 5 (a). In this case, there is also an advantage that the circumferential width Wg of each of the stator magnetic poles 7a and 7b is wider than the width Wt of the teeth 71 as shown in FIG.

  (4) Further, since the stator magnetic poles 7a and 7b are connected by the yoke 41, in order to make the stator 4 as light as possible, the yoke 41 and the overlapping portions of the stator magnetic poles 7a and 7b are arranged as shown in FIG. It is preferable to form a recess 9 having a shape penetrating through 41 and having a portion of the stator magnetic poles 7a and 7b dug thinly. Even if the concave portion 9 is formed, the magnetic flux advances alternately in the circumferential direction and the axial direction through the yoke 41 and the non-excited stator magnetic poles 7a and 7b as shown by the broken line arrows in the partially enlarged view of FIG. Does not occur.

  (5) The yoke 41 has a larger outer diameter and a smaller inner diameter than the protruding portions of the stator magnetic poles 7a and 7b. Specifically, as shown in FIG. 7, the yoke 41 and the stator magnetic poles 7 a and 7 b have an inner diameter Ysi and an outer diameter Yse of the yoke 41 and an inner diameter Msi and an outer diameter Mse of the stator magnetic poles 7 a and 7 b. > Mse> Msi> Ysi, and the end surface of the yoke 41 is formed wider than the stator magnetic poles 7a and 7b.

  (6) The yoke 41 may have a circular disk shape in plan view. However, in order to reduce the weight of the motor 1A, as shown in FIG. 8, a portion on the extension line at the center of each of the stator magnetic poles 7a and 7b on the outer periphery. The recess 10 may be formed by notching the outer periphery of the yoke 41 and the outer periphery of the yoke 41 may be formed in a gear shape. Further, a portion on the extension line at the center of each stator magnetic pole 7a, 7b on the inner peripheral edge side of the yoke 41 may be cut out to form a similar recess, and the inner peripheral side of the yoke 41 may be formed in a gear shape. Furthermore, both the outer peripheral side and the inner peripheral side of the yoke 41 may be formed in a gear shape.

  (7) The coils 8 of the stator magnetic poles 7a and 7b are practically composed of a U-shaped coil bobbin or a combination of a plurality of square-shaped coil bobbins mounted on the stator magnetic poles 7a and 7b as shown in FIG. 11 is wound. At that time, the coil bobbins 11 are coupled to each other by the coupling means so that the coil bobbins 11 on both end surfaces of the stator 4 are not detached from the stator 4. Specifically, the coupling means includes resin-made clips 12 inserted into the respective recesses 11, and the clips 12 sandwich the flange portions of the coil bobbins 11 on both end surfaces of the stator 4 and are engaged with the yoke 41. .

[Configuration of Rotors 3a and 3b]
(8) As shown in the enlarged perspective view of the rotors 3a and 3b and the magnetic path forming member 5 in FIG. The end face or outer peripheral surface of the magnetic path forming member 5 is joined, and the magnetic path forming member 5 forms an axial magnetic path from the rotor 3b to the rotor 3a of the magnetic flux of the stator 4.

  (9) Since the rotor magnetic poles 6 of the rotors 3a and 3b are displaced in the circumferential direction from the stator magnetic poles 7a and 7b, the arrangement positions are set in accordance with the opposing stator magnetic poles 7a and 7b. The arrangement positions of the rotor magnetic poles 6 of the rotors 3a and 3b may be further shifted from the circumferential shift of the stator magnetic poles 7a and 7b.

  (10) The rotor magnetic poles 6 of the rotors 3a and 3b having the same shape have a structure protruding in the axial direction from the yoke 31, for example, as shown in FIG. When the magnetic field is generated, it is formed using a permanent magnet and has a magnetic polarity opposite to that of the opposing stator magnetic poles 7a and 7b. Each rotor magnetic pole 6 may not protrude from the yoke 31 in the axial direction.

  (11) As shown in the rotor 3b of FIG. 10A, the yoke 31 of the rotors 3a and 3b has, for example, an inner diameter Yri and an outer diameter Yre of the yoke 31, and an inner diameter Mri and an outer diameter Mre of the rotor magnetic pole 6. The yoke 31 may be formed wider than the rotor magnetic pole 6 so as to satisfy the relationship of Yre> Mre> Mri> Yri. However, as shown in FIG. 10B, the rotor magnetic pole 6 is elongated in the motor axis direction. More preferably, Mri = Yri, and the inner peripheral surface of the rotor magnetic pole 6 and the inner peripheral surface of the yoke 31 are directly connected to the outer peripheral surface of the magnetic path forming member 5.

  (12) As for the rotors 3a and 3b, in order to further reduce the weight of the motor 1A, etc., as shown in FIGS. 8 and 9, portions corresponding to the back side of the rotor magnetic poles 6 of the yoke 31 are cut out (punched). The recess 13 is preferably formed. Even when the recess 13 is formed, the magnetic flux alternately passes through the yoke 31 and the rotor magnetic pole 6 and advances in the circumferential direction and the radial direction, and the magnetic path of the magnetic flux is formed in the rotors 3a and 3b without any problem.

  (13) In order to further reduce the weight of the motor 1A, the yoke 31 of the rotors 3a and 3b is also formed by cutting out portions on the extension lines of the rotor magnetic poles 6 on the outer peripheral edge as shown in FIGS. 14 may be formed, and the outer peripheral side of the yoke 31 may be formed in a gear shape. Further, a portion on the central extension line of each rotor magnetic pole 6 on the inner peripheral side of the yoke 31 may be cut out to form a similar recess, and the inner peripheral side of the yoke 31 may be formed in a gear shape, or Yre = Mre may be used. Further, both the outer peripheral side and the inner peripheral side of the yoke 31 may be formed in a gear shape. Furthermore, a portion where the outer diameter of the yoke 31 is smaller than the magnetic pole outer diameter Mre may be provided between the magnetic poles.

  Since the motor 1A of the present embodiment has the above-described configuration, the following effects can be obtained.

[Effects regarding stator 4]
<1> The stator 4 is formed by providing the stator magnetic poles 7a, 7b on the both end facets 41a, 41b side of one yoke 41. At that time, all the stator magnetic poles 7a on the one end face 41a side are excited to the S pole, All the stator magnetic poles 7b on the other end face 41b side are excited to N poles. Further, by shifting the arrangement positions of the stator magnetic pole 7a and the stator magnetic pole 7b in the circumferential direction, when the motor 1A is viewed from the axial direction, the stator 4 is placed between the other S pole of the S pole on the one end face 41a side and between the other stator poles 7a An N-pole stator magnetic pole 7b on the side of the end face 41b is located, and this is equivalent to a state in which the total number of magnetic poles of the stator 4 is doubled. For example, the magnetic flux generated from the N-pole rotor magnetic pole 6 of one rotor 3a is the S pole on the one end face 41a side of the stator 4, the N pole on the other end face 41b side shifted in the circumferential direction, and the other rotor It passes through a three-dimensional magnetic path that passes through the S pole of 3b and the magnetic path forming member 5 and returns to the N pole of one rotor 3a. In this case, the magnetic flux passes through the yoke 41 of the stator 4 in one direction, and the circumferential magnetic path of the yoke 41 becomes shorter as the number of magnetic poles increases, in other words, the number of magnetic fluxes passing through the yoke of the stator 4, in other words, Since the magnetic path cross-sectional area of the yoke 41 is reduced, the axial thickness of the stator 4 can be drastically reduced. Therefore, the motor 1A having an axial gap structure can be formed in an unprecedented small (thin) and light weight, and a novel motor 1A having an axial gap structure having a small output and a large output can be provided.

  <2> In the stator 4, the N pole and the S pole of the same phase (A phase, B phase, C phase) can be separated, so that there is also an advantage that the leakage magnetic flux that short-circuits between these magnetic poles can be reduced. . As a result, the leakage inductance of the motor 1A can be reduced, and the output can be increased particularly in the middle and high speed rotation regions.

  <3> By utilizing the stator magnetic poles 7a and 7b of the other phases that are not excited as magnetic paths in the circumferential direction of the yoke 41, the configurations of (4) to (7) in [Configuration of the stator 4] are formed. The stator 4 can be further reduced in size and weight, and the motor 1A can be further reduced in thickness and weight. In addition, the yoke 41 has a larger outer diameter than the magnetic pole portion of the stator 4 and a smaller inner diameter, so that the yoke thickness for satisfying the necessary magnetic path cross-sectional area in the circumferential direction can be reduced, and the stator 4 can be made thinner. .

[Effects on rotors 3a and 3b]
For the rotors 3a and 3b, similarly to the stator 4, the rotor magnetic poles 6 corresponding to the non-excited other-phase stator magnetic poles 7a and 7b are utilized as magnetic paths in the circumferential direction and radial direction of the yoke 31, and the [rotor 3a 3b], the rotors 3a and 3b can be further reduced in size and weight, and the motor 1A can be further reduced in thickness and weight.

  Therefore, the rotors 3a and 3b and the stator 4 are made small (thin) and light, and the axial gap structure motor 1A is made smaller (thin) and lighter than before. A novel motor 1A having an axial gap structure can be provided.

(Second Embodiment)
A second embodiment will be described with reference to FIGS. In these drawings, the same reference numerals as those in FIGS. 1 to 10 denote the same or corresponding parts, FIG. 11 is a sectional view along the motor shaft of the motor 1B of the present embodiment, and FIGS. It is explanatory drawing of a field.

  The motor 1B of the present embodiment is different from the motor 1A of the first embodiment in that a gap between the stator 4 and the magnetic path forming member 5 in the center hole 42 of the stator 4 is on the both end surfaces 41a and 41b side of the stator 4. An axial annular field coil 15 for generating a field in the direction of exciting the stator magnetic poles 7a and 7b, that is, a field in the direction of exciting the stator magnetic pole 7a to the S pole and the stator magnetic pole 7b to the N pole is provided. It is a point that is arranged. In addition, since the field coil 15 is arrange | positioned, in the case of this embodiment, a permanent magnet is not used for each rotor magnetic pole 6 of rotor 3a, 3b.

  The field generated by the field coil 15 can improve torque and current off characteristics as will be described below.

[Explanation of torque increase by application of field]
When the field of the field coil 15 is not applied, the magnetization curve shown in FIG. 12A starts from the state where the current i and the magnetic flux Ψ are 0 between the start of energization of each coil 8 of the stator 4 and the end of energization. The output of the motor 1B is proportional to the area Sa of conversion energy surrounded by the magnetization curve. The area Sb in the figure indicates the energy returned to the power supply side.

  When the field of the field coil 15 is applied, by applying the field, the magnetization curve is as shown in FIG. 12B, and the starting point where the current i and the magnetic flux Ψ is 0 is indicated by the arrow line as shown in FIG. Move to the left (advance direction). As a result, the area Saa of the conversion energy surrounded by the magnetization curve becomes larger than the area Sa, and the torque output of the motor 1B increases. Note that a region Sbb in FIG. 12B indicates energy returned to the power supply side.

[Improvement of current off characteristics of motor 1A by application of field]
The time Δt required to turn off the current of the coil 8 at the end of energization of each coil 8 of the stator 4 is obtained from Δt = Ψ / V, where Ψ is a magnetic flux and V is an electromotive force.

  When the field of the field coil 15 is applied, the magnetization curve moves leftward from the broken line to the solid line as shown in FIG. Therefore, the time required to turn off the energization current of the coil 8 from the maximum current imax to 0 is the time Δt0 when the magnetic flux change ΔΨ0 = V × Δt0 from Ψmax0 to 0 occurs when the field coil 15 is not applied. Whereas (= ΔΨ0 / V), when the field of the field coil 15 is applied, the magnetic flux change ΔΨ1 = V × Δt1 from Ψmax1 to Ψ0 is reduced to time Δt1 (= ΔΨ1 / V). . Since Δψ0> Δψ1, Δt0> Δt1.

  Therefore, in the case of the present embodiment, by applying the field of the field coil 15, the motor 1 </ b> B further increases the torque and the output is increased as compared with the motor 1 </ b> A. And since the field coil 15 is arrange | positioned so that the center hole 42 of the stator 4 may pass like the magnetic path structure member 5, the motor 1B is not enlarged by the field coil 15. Therefore, it is possible to provide the motor 1B having a further increased output without increasing the size.

  Further, by applying the field of the field coil 15, there is an advantage that the current of the motor 1B can be easily turned off particularly when the rotors 3a, 3b and the stator 4 are opposed to the magnetic poles. Can be reduced in a short time, so that the copper loss is reduced and the efficiency of the motor 1B is improved. In addition, the generation of negative torque (regenerative torque) due to the continued flow of current even after the end of energization can be reduced, and the effect of increasing the average torque particularly during high-speed rotation also occurs.

(Third embodiment)
A third embodiment will be described with reference to FIGS. 14 and 15. In these drawings, the same reference numerals as those in FIGS. 1 to 13 denote the same or corresponding parts, FIG. 14 is a sectional view taken along the motor shaft of the motor 1C as an example of this embodiment, and FIG. It is sectional drawing along the motor shaft of motor 1D of the example of.

  First, the motor 1C of FIG. 14 is different from the motor 1A of the first embodiment in that the rotor magnetic poles 6 of both the rotors 3a and 3b are formed with end surface portions 61 that form a magnetic pole surface as an uneven surface, and the stator 4 Each of the stator magnetic poles 7a and 7b is also provided with end face portions 71a and 71b for forming the magnetic pole surface as an uneven surface.

  When the magnetic pole surfaces of the rotor magnetic poles 6 and the magnetic pole surfaces of the stator magnetic poles 7 a and 7 b are formed on the concave and convex surfaces, the magnetic pole surfaces of the rotors 3 a and 3 b and the stator 4 are formed on the concave and convex surfaces that are concentric with the motor shaft 2. . The convex portion of the uneven surface is made thicker on the root side than on the tip side. (3) The convex portion of the stator 4 is arranged on the outermost peripheral side. There are a plurality of convex portions of the rotors 3a and 3b, and the height of the convex portions in the motor axial direction is preferably lower on the outer peripheral side than on the inner peripheral side in consideration of centrifugal force and the like. In addition, the uneven | corrugated space | interval is set to the magnitude | size beyond the gap of rotor 3a, 3b and the stator 4. FIG.

  In the motor 1 </ b> C, the rotor magnetic poles 6 of the rotors 3 a and 3 b and the magnetic pole surfaces of the stator magnetic poles 7 a and 7 b of the stator 4 are formed on the uneven surface, so that the rotors 3 a and 3 b and the stator 4 face each other. The magnetic pole surface becomes wider, the torque can be further increased, and the motor output can be further increased.

  Next, the motor 1D shown in FIG. 15 is a further improvement of the motor 1C. The motor 1D is different from the motor 1C in that the end face 61 serving as the magnetic pole face of each rotor magnetic pole 6 of both the rotors 3a and 3b and the stator 4 The concave and convex surfaces of the end surfaces 71a and 71b, which are the magnetic pole surfaces of the stator magnetic poles 7a and 7b, are rounded by “R removing” the root and tip portions of the convex portions, and are rounded. Has the same effect as the motor 1C.

  The present invention is not limited to the above-described embodiments, and various modifications other than those described above can be made without departing from the spirit thereof. For example, in each of the motors 1A to 1D, Instead of the stator 4 of each embodiment, a stator 4 * shown in FIG. 16 may be arranged. The stator 4 * in FIG. 16 is a yoke piece 41 * in which each stator magnetic pole 7a, 7b is extended in the axial direction from both circumferential ends of the stator magnetic poles 7a, 7b toward the adjacent stator magnetic poles 7b, 7a. Connected to form. At this time, each yoke piece 41 * forms an angle of, for example, 120 ° with respect to the motor shaft direction as shown in the enlarged view of the circled portion in FIG. The magnetic flux travels in the circumferential direction and the radial direction through the stator 4 * by magnetic paths that alternately pass through the non-excited stator magnetic poles 7a and 7b. Therefore, the stator 4 * acts in the same manner as the stator 4. Further, in the stator 4 *, the yoke piece 41 * does not exist at all between the back surfaces of the stator magnetic poles 7a and 7b on both end faces, and does not serve as a partition wall for the stator magnetic poles 7a and 7b. The coil can be made closer to the axial direction, can be made thinner than the stator 4, and the motors 1A to 1D can be further reduced in size and weight. Further, as described above, since each yoke piece 41 * forms an angle of, for example, 120 ° with respect to the motor shaft direction, as shown by the broken line in the enlarged view of FIG. When the coil 8 * is concentratedly wound, the round enameled wire can be ideally stacked to form the coil 8 *, and there is an advantage that the space factor of the coil 8 * can be improved.

  Next, in the rotors 3a and 3b of the motors 1A to 1D, instead of the recesses 13 in FIG. 9, as shown in FIG. 17, a V-shaped recess 13 * that is symmetrical at the center of each rotor magnetic pole 6 is provided. It may be formed.

  Next, it is possible to combine a plurality of combinations of the rotors 3a and 3b and the stator 4 (or the stator 4 *) of each of the above embodiments by reversing the arrangement for each set. The rotor 3b (or 3a) in between may be formed using the yoke 31 in common. Specifically, for example, in the case of a two-stage configuration, it may be formed as shown in FIG.

  18, the same reference numerals as those in FIGS. 1 to 17 denote the same or corresponding elements. A motor 1 </ b> E in FIG. 18 includes a rotor 3 a, a stator 4, a rotor 3 b, a rotor 3 b, a stator 4 (direction of an end surface). On the other hand, the other set of rotors 3b is arranged in series with the motor shaft 2, and the number of rotors 3b between the stages sandwiched between the stators 4 is one. 6 is formed. In this case, the stator coil 8 is excited so that the rotor magnetic poles 6 on both end faces of the rotor 3b sandwiched between the two stators 4 are excited to the same polarity. The multi-stage motor 1E configured as described above can make a large number of multi-stage rotor magnetic poles 6 and stator magnetic poles 7a and 7b close to each other with a short shaft length, and can obtain a large output with an extremely small and lightweight structure. it can.

In the case of the motor 1E shown in FIG. 18, a stepped portion α for positioning the rotors 3a and 3b is formed on the motor shaft 2, and a stepped portion β for positioning the stator 4 is formed on the inner surface side of the outer case 16. It is formed. Therefore, when the motor 1E is assembled, the rotors 3a and 3b can be easily positioned in the axial direction by the stepped portion α, and the stator 4 can be easily positioned in the axial direction by the stepped portion β. it can. Therefore, the positioning using the stepped portions α and β can ensure the axial interval (gap length) and the parallelism of the rotor magnetic pole 6 and the stator magnetic poles 7a and 7b. It is possible to improve motor frequency by accurately managing motor output and the like.

  Note that the third, fourth,. . . Of course, the multi-stage configuration is the same as the two-stage case of FIG. 18, and the same effect can be obtained.

  Next, it is needless to say that the motor according to the present invention may be driven by multiple phases of four or more phases. Further, the number of rotor magnetic poles 6 and stator magnetic poles 7a and 7b are not limited to those of the above-described embodiments. Furthermore, the magnetic poles of the stator magnetic poles 7a and 7b may be opposite to those of the embodiments.

  The present invention can be applied to an axial gap structure motor for various uses such as a drive motor for an electric vehicle.

1A to 1E Motor 2 Motor shaft 3a, 3b Rotor 4 Stator 5 Magnetic path forming member 6 Rotor magnetic pole 7a, 7b Stator magnetic pole 8 Stator coil

Claims (3)

In motors with an axial gap structure,
Two rotors arranged in the axial direction of the motor shaft;
One stator disposed between the rotors and having a motor shaft passing through a central hole;
A magnetic path forming member that is connected to the rotors via the center hole and forms a magnetic path between the rotors;
The two rotors have a plurality of rotor magnetic poles arranged in a circumferential direction on an end surface facing the stator,
In the stator, a plurality of stator magnetic poles that are excited by one magnetic pole property are arranged in the circumferential direction on one end face side that faces either one of the rotors, and faces the other of the rotors. by the other end face side and the other magnetic pole plurality of stator magnetic poles to be excited in the resistance are disposed offset from the circumferential direction each stator pole of said one end surface, from the rotor poles of one of the rotor The emitted magnetic flux passes through the stator magnetic pole on the one end face side of the stator, the stator magnetic pole on the other end face side shifted in the circumferential direction, the rotor magnetic pole of the other rotor, and the magnetic path forming member. Returning to the rotor magnetic poles of the rotor of the motor. The motor according to claim 1,
A field coil that generates a field in a direction to excite each stator magnetic pole on both end surfaces of the stator is disposed in a gap between the stator in the center hole and the magnetic path forming member. motor. The motor according to claim 1 or 2,
Each of the rotor magnetic poles of the two rotors and each stator magnetic pole of the stator has a magnetic pole surface formed in an uneven surface.

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