JP2020003230A - Resolver - Google Patents

Abstract

To provide a resolver capable of effectively improving detection accuracy of a rotational position of a rotor and achieving downsizing and lower cost.SOLUTION: A resolver comprises: a resolver stator core 25; a resolver rotor core 42 facing the resolver stator core 25 in a rotational axis direction; a stator transformer coil and an excitation coil provided in the resolver stator core 25; and a rotor transformer coil and a detection coil provided in the resolver rotor core 42. At least a slit 38 or 39 having higher electric resistance than the resolver stator core 25 and the resolver rotor core 42 and blocking a flow of an eddy current is provided in at least the resolver stator core 25 or the resolver rotor core 42 and in a region overlapping a part of the location in which at least the stator transformer coil, the rotor transformer coil, the excitation coil, and the detection coil are arranged.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a resolver.

  For example, a brushless motor detects the rotational position of a rotor and controls the current supplied to the stator based on the detection result. As a means for detecting the rotational position of the rotor, for example, a resolver is used. Among the resolvers, there is a so-called sheet coil type resolver. This includes a plate-shaped stator core fixed to a motor case or the like, and a plate-shaped rotor core fixed to a rotating shaft of a rotor and facing the stator core in the axial direction.

  On the surface of the stator core facing the rotor core, a stator transformer coil disposed at the center in the radial direction and an exciting coil (resolver stator coil portion) disposed concentrically with the stator transformer coil so as to surround the stator transformer coil. ) And are provided. The stator transformer coil and the excitation coil are electrically disconnected.

  On the other hand, on the surface of the rotor core facing the stator core, the rotor transformer coil is disposed at the center in the radial direction, and faces the stator transformer coil in the axial direction. And a detection coil (resolver rotor coil) disposed at the same position. The rotor transformer coil and the detection coil are connected in series.

  In such a configuration, when a high-frequency input signal (voltage) is applied to the exciting coil by external power and an alternating current flows, an alternating magnetic flux is generated in the stator. Due to this alternating magnetic flux, an induced voltage is generated in the detection coil (electromagnetic induction is generated), and an alternating current flows. This alternating current is supplied to the rotor transformer coil, and an alternating magnetic flux is generated at a position where the rotor transformer coil is provided. The alternating magnetic flux generates an induced voltage in the stator transformer coil.

  Here, the rotation of the rotor causes a phase difference between the input signal applied to the excitation coil and the output signal (voltage) of the stator transformer coil. By detecting this phase difference, the rotational position of the rotor can be detected.

  When the exciting coil and the stator transformer coil are formed on the same core, the alternating magnetic flux generated in the exciting coil affects the stator transformer coil. In order to suppress this effect, a conventional technique has been disclosed in which a gap is provided in a core between an excitation coil and a stator transformer coil.

JP 2011-17584 A

  By the way, when an alternating magnetic flux is generated in the exciting coil, an eddy current is generated in the stator core around the exciting coil with the change in the magnetic flux. Further, since the alternating magnetic flux of the excitation coil passes through the opposed detection coil, an eddy current also occurs in the rotor core around the detection coil of the rotor core. Further, an eddy current is generated in the rotor core around the rotor transformer coil and the stator core around the stator transformer coil facing the rotor transformer coil due to the alternating magnetic flux generated in the rotor transformer coil connected in series to the detection coil. These eddy currents generate a magnetic flux in a direction that hinders a current change occurring in the coil. For this reason, the alternating magnetic flux desired to be generated by the excitation coil and the rotor transformer coil and the current generated by the detection coil are reduced. As a result, the output signal obtained from the stator transformer coil is attenuated.

  The above-described prior art is excellent in that a gap is provided between the exciting coil and the stator transformer coil and both are magnetically separated, so that magnetic flux does not interfere via a common core (stator core). However, the influence of the eddy current generated in the core around each coil cannot be suppressed. For this reason, due to the eddy current, the alternating magnetic flux generated in the excitation coil and the rotor transformer coil is reduced, and the signal is weakened, so that the detection accuracy of the rotational position of the rotor may not be improved.

  Further, in the above-described conventional technology, in order to magnetically separate the core provided with the excitation coil and the detection coil from the core provided with each transformer coil, the width of the groove or slit provided in each core is reduced. The size needs to be set to a sufficient size. Accordingly, there is a possibility that the resolver becomes large and the manufacturing cost increases.

  Therefore, the present invention provides a resolver that can effectively improve the accuracy of detecting the rotational position of the rotor, and can reduce the size and cost.

  In order to solve the above problems, a resolver according to the present invention includes a stator core, a rotor core rotatably provided with respect to the stator core, and a rotor core facing the stator core in a rotation axis direction, and a first core provided on the stator core. A transformer coil, a second transformer coil provided on the rotor core and facing the first transformer coil, an exciting coil provided on the stator core and provided concentrically with the first transformer coil, and a second transformer coil provided on the rotor core. And a detection coil facing the excitation coil, and at least one of the stator core and the rotor core, and at least the first transformer coil, the second transformer coil, the excitation coil, and the detection coil. In the area that partially overlaps the place where Stator core, and the higher electrical resistance than the rotor core, the resistance unit that inhibits the flow of eddy currents, characterized in that it is provided at least one.

  As described above, by providing the resistance portion on at least one of the stator core and the rotor core, the magnitude of the eddy current generated in the stator core or the rotor core can be reduced. For this reason, it is possible to suppress a decrease in the alternating magnetic flux formed by at least one of the transformer coil, the exciting coil, and the detection coil due to the eddy current. Therefore, the detection accuracy of the rotational position of the rotor can be effectively improved.

In the resolver according to the present invention, the resistance portion is formed along a radial direction orthogonal to a rotation axis direction of the rotor core.
Further, the resistance portion may be curved so as to be along a rotation direction of the rotor core when viewed from a rotation axis direction.

  With such a configuration, the eddy current generated in any of the cores can be effectively reduced by the resistance portion. For this reason, the detection accuracy of the rotational position of the rotor can be reliably improved.

In the resolver according to the present invention, the stator core and the rotor core are formed in a plate shape, and the resistance portion is a slit formed in at least one of the stator core and the rotor core. .
Further, the resistance portion may be a concave portion formed in at least one of the stator core and the rotor core.

  In this manner, the resistance portion can be formed with a simple structure such as a concave portion or a slit. Therefore, the manufacturing cost of the resolver can be further reduced.

  According to the present invention, the magnitude of the eddy current generated in the stator core or the rotor core can be reduced by providing the resistance portion in at least one of the stator core and the rotor core. For this reason, it is possible to suppress a decrease in the alternating magnetic flux formed by at least one of the transformer coil, the exciting coil, and the detection coil due to the eddy current. Therefore, the detection accuracy of the rotational position of the rotor can be effectively improved.

FIG. 2 is a cross-sectional view along the axial direction of the brushless motor according to the first embodiment of the present invention. It is the A section enlarged view of FIG. FIGS. 3A and 3B are plan views of a formation pattern of an exciting coil according to the first embodiment of the present invention, as viewed in a direction indicated by an arrow Y in FIG. 2, wherein FIG. The back surface of the insulating sheet is shown. It is the top view which looked at the resolver stator core in a 1st embodiment of the present invention from the direction of an axis. It is the figure which projected the stator transformer coil and the sine excitation coil on the resolver stator core in 1st Embodiment of this invention. FIG. 3 is a plan view of a front surface side of a third insulating sheet according to the first embodiment of the present invention when viewed from a direction of an arrow Y in FIG. 2. It is a partial enlarged view of a resolver stator core and a resolver rotor core in the first embodiment of the present invention. It is the top view which looked at the resolver stator core and the resolver rotor core in the modification of a 1st embodiment of the present invention from the direction of an axis. It is the top view which looked at the resolver stator core and the resolver rotor core in the modification of a 1st embodiment of the present invention from the direction of an axis. It is the top view which looked at the resolver stator core and the resolver rotor core in the modification of a 1st embodiment of the present invention from the direction of an axis. It is the figure which projected the stator transformer coil and the sine excitation coil on the resolver stator core in the modification of 1st Embodiment of this invention. It is the top view which looked at the resolver stator core and the resolver rotor core in the modification of a 1st embodiment of the present invention from the direction of an axis. It is the top view which looked at the resolver stator core and the resolver rotor core in the modification of a 1st embodiment of the present invention from the direction of an axis. It is the top view which looked at the resolver stator core and the resolver rotor core in a 2nd embodiment of the present invention from the direction of an axis. It is the top view which looked at the resolver stator core and the resolver rotor core in the modification of a 2nd embodiment of the present invention from the direction of an axis. It is the top view which looked at the resolver stator core and the resolver rotor core in the modification of a 2nd embodiment of the present invention from the direction of an axis. It is the top view which looked at the resolver stator core and the resolver rotor core in the modification of a 2nd embodiment of the present invention from the direction of an axis. It is the top view which looked at the stator transformer coil in the modification of the embodiment of the present invention from arrow Y in FIG. It is the top view which looked at the rotor transformer coil and the detection coil in the modification of embodiment of this invention from arrow Y direction in FIG.

  Next, an embodiment of the present invention will be described with reference to the drawings.

(1st Embodiment)
(Brushless motor)
FIG. 1 is a cross-sectional view along the axial direction of a brushless motor 1 provided with a resolver 6 according to the present invention.
As shown in FIG. 1, the brushless motor 1 includes a substantially bottomed cylindrical motor case 2, a substantially disk-shaped bracket 3 for closing an opening 2 a of the motor case 2, and a brushless motor 1 housed in the motor case 2. A motor stator 4, a motor rotor 5 rotatably provided with respect to the motor stator 4, and a resolver 6 for detecting a rotational position of the motor rotor 5.
In the following description, the rotation axis direction of the motor rotor 5 is simply referred to as an axial direction, the rotation direction of the motor rotor 5 is referred to as a circumferential direction, and the radial direction of the motor rotor 5 orthogonal to the axial direction and the circumferential direction is simply referred to as a radial direction.

  The outer peripheral surface of the motor stator 4 is fitted and fixed to the inner peripheral surface of the peripheral wall 2 b of the motor case 2. A bearing housing 7 projecting toward the motor stator 4 is provided substantially at the center of the bottom wall 2c of the motor case 2 in the radial direction. This bearing housing 7 is provided with a bearing 8 for rotatably supporting the one end 13a side (the lower side in FIG. 1) of the rotating shaft 13 of the motor rotor 5.

  The motor stator 4 has a substantially cylindrical motor stator core 9. The outer peripheral surface of the motor stator core 9 is fitted to the inner peripheral surface of the peripheral wall 2b of the motor case 2. The motor stator core 9 is formed by laminating metal plates (electromagnetic steel plates) punched out in a substantially annular shape by press working in the axial direction. However, it is also possible to form the motor stator core 9 by pressing soft magnetic powder.

  A plurality of teeth 10 projecting radially inward are formed on the inner circumferential surface of the motor stator core 9 so as to be arranged in the circumferential direction. These teeth 10 are wound with coils 10a. The terminal of each coil 10a is electrically connected to an external power supply (both not shown) via a control unit. Then, a current is selectively supplied to each coil 10a by a control unit (not shown). When a current is supplied to each coil 10a, a desired magnetic flux is formed in the motor stator 4.

At a substantially radial center of the bracket 3, a bearing housing 11 protruding toward the motor stator 4 is provided. The bearing housing 11 is provided with a bearing 12 for rotatably supporting the other end 13 b side (upper side in FIG. 1) of the rotating shaft 13 of the motor rotor 5.
The bracket 3 has a recess 3b on one surface 3a opposite to the motor stator 4. A resolver stator 21 (see FIG. 2) that forms one of the resolvers 6 is fixed to the concave portion 3b. The detailed structure of the resolver 6 will be described later.

The motor rotor 5 includes a rotating shaft 13 whose both ends are rotatably supported by the bearings 8 and 12, and a motor rotor core 14 fixed to a position of the rotating shaft 13 corresponding to the motor stator 4.
The motor rotor core 14 is formed in a substantially columnar shape. The motor rotor core 14 is formed by laminating metal plates (electromagnetic steel plates) punched out in a substantially annular shape by press working in the axial direction. However, it is also possible to form the motor rotor core 14 by press-molding soft magnetic powder.

The motor rotor 5 has a magnet (not shown). Magnetic attraction or repulsion is generated between the magnetic flux of the magnet and the magnetic flux formed on the motor stator 4, and the motor rotor 5 rotates. Note that the motor rotor 5 may not include a magnet. In this case, the motor rotor 5 is rotated by magnetic attraction generated between the motor rotor 4 and the magnetic flux of the motor stator 4.
Further, a through hole 14a is formed substantially at the center in the radial direction of the motor rotor core 14 so as to penetrate in the axial direction. The rotating shaft 13 is fixed to the through hole 14a by, for example, press fitting.

  The other end 13 b of the rotating shaft 13 on the bracket 3 side protrudes axially outward via the bearing 12. A resolver rotor 22 (see FIG. 2) that constitutes the other side of the resolver 6 is fixed to the protruding portion.

(Resolver)
FIG. 2 is an enlarged view of a portion A in FIG. In addition, in FIG. 2 and subsequent figures, the scale of each part is appropriately changed and shown for easy understanding.
As shown in FIG. 2, the resolver 6 is a so-called sheet coil type resolver. The resolver 6 has a substantially disk-shaped resolver stator 21 fixed to the bracket 3, and is disposed at a predetermined interval on the opposite side of the resolver stator 21 from the bracket 3, and substantially faces the resolver stator 21 in the axial direction. And a disc-shaped resolver rotor 22.

(Resolver stator)
The resolver stator 21 has a resolver stator portion 23 formed in a substantially disk shape. The resolver stator portion 23 is disposed so as to be in contact with the concave portion 3b of the bracket 3. The resolver stator 21 is fixed to the bracket 3.
At a substantially radial center of the resolver stator portion 23, a cylindrical portion 24 is formed so as to protrude toward a side opposite to the bracket 3. The inner diameter of the cylindrical portion 24 is set to be larger than the shaft diameter of the rotating shaft 13. The other end 13b of the rotating shaft 13 protrudes from the resolver stator 21 toward the resolver rotor 22 via such a cylindrical portion 24.

On the surface 23a of the resolver stator portion 23 facing the resolver rotor 22, a substantially annular concave portion 23b is formed on most of the surface except the cylindrical portion 24 when viewed from the axial direction. The resolver stator core 25 is disposed in the recess 23b. The concave portion 23b is provided for facilitating the positioning of the excitation coil 29 and the like described later, and the resolver stator portion 23 may be a flat plate.
The resolver stator core 25 is made of a magnetic material, and is formed in a substantially annular shape when viewed from the axial direction so as to correspond to the shape of the concave portion 23b. That is, an opening 25 a through which the cylindrical portion 24 can be inserted is formed substantially at the center of the resolver stator core 25 in the radial direction. The resolver stator core 25 is for increasing the efficiency of forming an alternating magnetic flux by the excitation coil 29 described later.

  A first insulating sheet 26 and a second insulating sheet 27 are sequentially laminated on one surface 25b of the resolver stator core 25 opposite to the resolver stator portion 23 and facing the resolver rotor 22. The first insulating sheet 26 and the second insulating sheet 27 are each formed in a substantially annular shape so as to correspond to the shape of the resolver stator core 25. That is, the first insulating sheet 26 and the second insulating sheet 27 have openings 26a and 27a at substantially the center in the radial direction, respectively, through which the cylindrical portion 24 can be inserted. Further, the first insulating sheet 26 and the second insulating sheet 27 are formed in the same shape, and are arranged concentrically with the resolver stator core 25, respectively.

  The excitation coil 29 and the stator transformer coil 30 are formed on the second insulating sheet 27. The first insulating sheet 26 is for securing insulation between the exciting coil 29 formed on the second insulating sheet 27, the crossover of the stator transformer coil 30 and the transformer coil 30 (not shown), and the resolver stator core 25. is there.

  Hereinafter, the configurations of the resolver stator core 25, the exciting coil 29, and the stator transformer coil 30 will be described in detail.

First, the configurations of the excitation coil 29 and the stator transformer coil 30 will be described in detail based on FIGS. 3A and 3B.
3A and 3B are plan views of the formation pattern of the exciting coil 29 viewed from the direction of the arrow Y in FIG. 2. FIG. 3A illustrates a surface 27 b of the second insulating sheet 27 on the resolver rotor 22 side, and FIG. , The back surface 27c of the second insulating sheet 27 on the first insulating sheet 26 side. In addition, in FIG. 3B, when the second insulating sheet 27 is viewed from the resolver rotor 22 side, the back surface 27 c side is originally not visible, but here, it is assumed that the second insulating sheet 27 is transmitted. The same applies to the third insulating sheet 43 shown in FIG. 6 and the second insulating sheet 27 and the third insulating sheet 43 shown in FIGS.

  Here, the excitation coil 29 is composed of two excitation coils 31, 32, a sin excitation coil 31 and a cos excitation coil 32, which are out of phase with each other. The exciting coils 31 and 32 and the stator transformer coil 30 are formed by performing a film forming process or the like on the second insulating sheet 27.

As shown in FIG. 3A, a stator transformer coil 30 and a sine excitation coil 31 are formed on a front surface 27b of the second insulating sheet 27.
The stator transformer coil 30 is formed in a spiral shape so as to surround the periphery of the opening 27a of the second insulating sheet 27. Both end portions 30a and 30b of the stator transformer coil 30 are electrically connected to a control unit (neither is shown) via a lead wire or the like.

The sin excitation coil 31 is formed so as to surround the periphery of the stator transformer coil 30. The sin excitation coil 31 has two poles. That is, the sin excitation coil 31 is composed of two spiral coils 33 and 34 that are substantially semicircular when viewed from the axial direction.
One spiral coil 33 of the two spiral coils 33, 34 is formed such that a small substantially semicircular loop is formed inside a large substantially semicircular loop, and the circumferential angle becomes larger toward the inner loop. It is formed to be small. The other spiral coil 34 of the two spiral coils 33, 34 is line-symmetric or point-symmetric (twice-rotation-symmetric) with one spiral coil 33 with respect to an arbitrary radial line passing through the rotation axis of the rotating shaft 13. ). In addition, if the axial angle of the resolver 6 is N (N is an integer of 2 or more), the resolver 6 may be formed to have 2N rotational symmetry.

  Further, the two spiral coils 33 and 34 are connected in series. That is, the end portions 33a, 33b, 34a, 34b of the two spiral coils 33, 34 are respectively defined as outer end portions 33a, 34a located radially outward and inner end portions 33b, 34b located radially inside. At this time, the inner terminal portion 33b of one spiral coil 33 and the outer terminal portion 34a of the other spiral coil 34 are connected. The coils 33 and 34 are connected such that the directions of the exciting currents flowing in each other are opposite to each other when viewed from the direction of arrow Y in FIG. 2, that is, opposite magnetic poles are generated. An outer terminal portion 33a of one spiral coil 33 and an inner terminal portion 34b of the other spiral coil 34 are electrically connected to a control unit (neither is shown) via a lead wire or the like. The connection lines between the spiral coils 33 and 34 are formed on the same surface on the insulating sheet and pass through a blank portion which does not adversely affect the alternating magnetic flux of the coils, or are formed on the back surface using a through hole or in a multilayer structure. In that case, it is better to pass through the other side. The same applies to the spiral coils 35 and 36 described below.

As shown in FIG. 3B, on the back surface 27c of the second insulating sheet 27 opposite to the front surface 27b, the stator transformer coil 30 is not formed, and the cos exciting coil 32 is formed.
The cos excitation coil 32 has the same basic configuration as the sin excitation coil 31. The cos excitation coil 31 is arranged so as to overlap the sin excitation coil 31 when viewed from the axial direction. However, the cos excitation coil 32 is arranged at a mechanical angle of 90 ° with respect to the sin excitation coil 31 when viewed from the axial direction. In the first embodiment, the resolver 6 has the double shaft angle of 1. However, in the case of the resolver having the double shaft angle N, the resolver 6 is arranged at a position shifted by 90 ° / N.

  The two spiral coils 35 and 36 constituting the cos exciting coil 32 are connected in series. That is, the end portions 35a, 35b, 36a, 36b of the two spiral coils 35, 36 are respectively defined as outer end portions 35a, 36a located radially outward and inner end portions 35b, 36b located radially inward. At this time, the inner terminal portion 35b of one spiral coil 35 and the outer terminal portion 36a of the other spiral coil 36 are connected. The one spiral coil 35 and the other spiral coil 36 are connected so that the directions of the exciting currents flowing in each other are opposite to each other when viewed from the arrow Y direction in FIG. 2, that is, opposite magnetic poles are generated. An outer terminal portion 35a of one spiral coil 35 and an inner terminal portion 36b of the other spiral coil 36 are electrically connected to a control unit (neither is shown) via a lead wire or the like.

Next, the configuration of the resolver stator core 25 will be described in detail with reference to FIG.
FIG. 4 is a plan view of the resolver stator core 25 as viewed from the axial direction.
As shown in FIG. 4, the resolver stator core 25 has a plurality of (for example, nine in the first embodiment) inner slits 38 extending radially outward from the periphery of the opening 25a. Is formed. The resolver stator core 25 is formed with a plurality of (for example, nine in the first embodiment) outer slits 39 extending radially inward from the outer peripheral edge 25c and radially inward. The inner slits 38 and the outer slits 39 are alternately arranged at regular intervals in the circumferential direction.

FIG. 5 is a diagram in which the stator transformer coil 30 and the sin excitation coil 31 shown in FIG. 3A are projected onto the resolver stator core 25. In FIG. 5, the stator transformer coil 30 and the sin excitation coil 31 are indicated by two-dot chain lines for easy understanding.
As shown in FIG. 5, the resolver stator core 25 has an inner peripheral side projected on the axial direction of the stator transformer coil 30 and an outer peripheral side projected on the axial direction of the sin excitation coil 31 (cos excitation coil 32). It is formed in a substantially annular shape so as to face upward. Here, the inner slit 38 and the outer slit 39 formed in the resolver stator core 25 extend so as to straddle the stator transformer coil 30, the sin excitation coil 31, and the cos excitation coil 32 in the radial direction.

(Resolver rotor)
Returning to FIG. 2, the resolver rotor 22 has a resolver rotor section 41 formed in a substantially disk shape. At a substantially radial center of the resolver rotor section 41, a through hole 41a penetrating in the thickness direction is formed. The other end 13b of the rotating shaft 13 is fixed to the through hole 41a by press fitting or the like. Thereby, the rotating shaft 13 and the resolver rotor 22 rotate integrally.

A concave portion 41c is formed at a large portion at the center in the radial direction on a surface 41b of the resolver rotor portion 41 facing the resolver stator 21. The resolver rotor core 42 is arranged in the concave portion 41c.
The resolver rotor core 42 is formed of a magnetic material, and its basic configuration is the same as that of the resolver stator core 25 (see FIG. 4). Therefore, hereinafter, the configuration of the resolver rotor core 42 will be described with the same reference numerals as those of the resolver stator core 25, and the detailed description of the resolver rotor core 42 will be omitted.

A third insulating sheet 43 is disposed on one surface 42 a of the resolver rotor core 42 opposite to the resolver rotor section 41. The third insulating sheet 43 is formed in a substantially disk shape so as to correspond to the shape of the resolver rotor core 42. An opening 43 a through which the rotating shaft 13 can be inserted is also formed at the radial center of the third insulating sheet 43.
A rotor transformer coil 44 and a detection coil 45 are formed on the surface 43b of the third insulating sheet 43 on the resolver stator 21 side by subjecting the third insulating sheet 43 to a film forming process or the like. The third insulating sheet 43 is for securing insulation between the rotor transformer coil 44 and the detection coil 45 and the resolver rotor core 42.

  Hereinafter, the configurations of the rotor transformer coil 44 and the detection coil 45 will be described in detail with reference to FIG.

FIG. 6 is a plan view of the front surface 43b side of the third insulating sheet 43 viewed from the direction of the arrow Y in FIG.
As shown in FIG. 6, the rotor transformer coil 44 is formed in a spiral shape so as to surround the periphery of the opening 43a of the third insulating sheet 43. The detection coil 45 is formed so as to surround the periphery of the rotor transformer coil 44. The detection coil 45 has two poles. That is, the detection coil 45 includes two spiral coils 46 and 47 having a substantially semicircular shape as viewed from the axial direction so as to correspond to the shape of the excitation coil 29. More specifically, the two spiral coils 46 and 47 are formed in a substantially semicircular shape having substantially the same size as the outermost loop shape of each of the exciting coils 31 and 32. Further, the two spiral coils 46 and 47 are formed symmetrically with respect to an arbitrary radial straight line passing through the rotation axis of the rotation shaft 13.

The rotor transformer coil 44 and the detection coil 45 (the spiral coils 46 and 47) formed in this way are connected in series.
That is, the end portions 46a, 46b, 47a, 47b of the two spiral coils 46, 47 are the outer end portions 46a, 47a located radially outward and the inner end portions 46b, 47b located radially inward, respectively. At this time, the inner terminal portion 46b of one spiral coil 46 and the inner terminal portion 47b of the other spiral coil 47 are connected.

The outer terminal portion 47a of the other spiral coil 47 is connected to the radially outer terminal portion 44a of the two terminal portions 44a and 44b of the rotor transformer coil 44.
Further, a radially inner terminal portion 44b of both terminal portions 44a and 44b of the rotor transformer coil 44 is connected to an outer terminal portion 46a of one spiral coil 46. That is, the rotor transformer coil 44 and the detection coil 45 form one closed circuit.

(Action of resolver)
Next, the operation of the resolver 6 will be described.
An excitation signal is previously input to the excitation coil 29 (sin excitation coil 31, cos excitation coil 32) of the resolver 6 via an external power supply (not shown) and a control unit. When an excitation signal is input to the excitation coil 29, a current is generated in the excitation coil 29, and an alternating magnetic flux is generated in the resolver stator 21 accordingly. More specifically, two alternating magnetic fluxes out of phase are generated in the resolver stator 21 by the two exciting coils 31, 32 (sin exciting coil 31, cos exciting coil 32) out of phase. Due to these alternating magnetic fluxes, an induced voltage is generated in the detection coil 45 of the resolver rotor 22, and an alternating current flows through the detection coil 45. This alternating current is generated in a form in which two alternating magnetic fluxes generated by the two exciting coils 31 and 32 are combined.

  Since the detection coil 45 is connected in series with the rotor transformer coil 44, a current also flows through the rotor transformer coil 44. Then, an alternating magnetic flux is generated in the resolver rotor 22. Due to the alternating magnetic flux (by electromagnetic induction), an induced voltage is generated in the stator transformer coil 30 of the resolver stator 21. Since the stator transformer coil 30 is connected to a controller (not shown), the induced voltage generated in the stator transformer coil 30 is output to the controller (not shown) as a signal.

Here, the principle of detecting the rotational position of the motor rotor 5 by the resolver 6 will be described.
As the motor rotor 5 rotates, the resolver rotor 22 rotates with respect to the resolver stator 21. When the resolver rotor 22 rotates and the position of the resolver rotor 22 with respect to the resolver stator 21 changes, an output output from the detection coil 45 via the transformer coils 30 and 44 with respect to a high-frequency input signal input to the excitation coil 29. The signal has a phase difference according to the rotational position. This phase difference is detected by a control unit (not shown), and the rotational position of the motor rotor 5 is detected.

FIG. 7 is a partially enlarged view of the resolver stator core 25 and the resolver rotor core 42, and corresponds to a portion B in FIG.
Here, as shown in FIG. 7, when an alternating current flows through each of the coils 31, 32, 44, and 45, an alternating magnetic flux is generated, and an eddy current U is generated in the resolver stator core 25 and the resolver rotor core. The eddy current U is generated in a vortex along the surface direction at the places where the coils 31, 32, 44, and 45 of the resolver stator core 25 and the resolver rotor core 42 are arranged, and at all positions around the coils. It occurs strongly. That is, the area where the coils 31, 32, 44, and 45 of the resolver stator core 25 and the resolver rotor core 42 are arranged and all surrounding areas, particularly the vicinity of the coil, are the generation region R of the eddy current U. In other words, the generation region R is a region that partially overlaps the portion where the coils 31, 32, 44, and 45 of the resolver stator core 25 and the resolver rotor core 42 are arranged. The eddy current U generates a magnetic flux in a direction that prevents the alternating current flowing through each of the coils 31, 32, 44, and 45, thereby hindering efficient formation of the alternating magnetic flux.

  However, in the resolver stator core 25 and the resolver rotor core 42, the inner slit 38 and the outer slit 39 are formed in the region R where the eddy current U is generated. These slits 38 and 39 obstruct the flow of the eddy current U. Moreover, the inner slit 38 and the outer slit 39 are formed so as to straddle the coils 31, 32, 44, and 45 in the radial direction so as to obstruct the flow of the eddy current U. For this reason, the magnitude of the eddy current U generated in the resolver stator core 25 and the resolver rotor core 42 can be reduced. As a result, the alternating magnetic flux can be efficiently formed by the coils 31, 32, 44, and 45.

  As described above, in the above-described first embodiment, the resolver stator core 25 and the resolver rotor core 42 have the inner slit 38 and the outer slit 39 in the generation region R of the eddy current U, which serve as resistance to the flow of the eddy current U. Is formed. For this reason, the magnitude of the eddy current U generated in the resolver stator core 25 and the resolver rotor core 42 can be reduced. As a result, the alternating magnetic flux can be efficiently formed by the coils 31, 32, 44, and 45. Therefore, as a result, a signal having a sufficient strength against disturbance noise can be obtained, and the detection accuracy of the rotational position of the motor rotor 5 by the resolver 6 can be effectively improved (so-called high S / N ratio can be achieved). ).

Further, an inner slit 38 and an outer slit 39 are formed in the resolver stator core 25 and the resolver rotor core 42 along the radial direction. For this reason, the magnitude of the eddy current U can be reduced, and the detection accuracy of the rotational position of the motor rotor 5 by the resolver 6 can be reliably improved.
Further, the inner slit 38 and the outer slit 39 are resistances of the flow of the eddy current U in the resolver stator core 25 and the resolver rotor core 42. As described above, since the flow of the eddy current U can be inhibited with a simple structure, the manufacturing cost of the resolver 6 can be reduced.

(Modification of First Embodiment)
In the first embodiment described above, the case where the inner slit 38 and the outer slit 39 formed in the resolver stator core 25 and the resolver rotor core 42 are arranged at equal intervals in the circumferential direction has been described. However, the present invention is not limited to this, and the inner slit 38 and the outer slit 39 need not be arranged at equal intervals.
In the above-described first embodiment, the case where the number of each of the slits 38 and 42 is nine has been described. However, the present invention is not limited to this, and the number of the slits 38 and 42 can be set arbitrarily.

  Further, in the first embodiment described above, the case where the inner slit 38 and the outer slit 39 along the radial direction are formed in the resolver stator core 25 and the resolver rotor core 42 as means for inhibiting the flow of the eddy current U is described. However, the present invention is not limited to this, and slits may be formed in the resolver stator core 25 and the resolver rotor core 42 so as to obstruct the flow of the eddy current U. Hereinafter, a specific modification will be described with reference to FIGS. 8 to 11.

  For example, as shown in FIG. 8, the resolver stator core 25 and the resolver rotor core 42 may be provided with a plurality of slits 51 formed over the entire radial direction. Each slit 51 is formed at equal intervals in the circumferential direction. However, the slits 51 need not be formed at equal intervals in the circumferential direction.

  By the way, when the slit 51 is formed in the resolver stator core 25 and the resolver rotor core 42 over the entire radial direction as in the present modification, the resolver stator core 25 and the resolver rotor core 42 are divided in the circumferential direction. In such a case, although not shown, it is desirable to provide a portion for connecting each of the divided resolver stator cores 25 and the resolver rotor core 42 (the same applies to the following embodiments and modified examples). With this configuration, the resolver stator core 25 and the resolver rotor core 42 can be integrated, so that the productivity of the resolver stator core 25 and the resolver rotor core 42 can be improved.

  As shown in FIG. 9, a plurality of (for example, five in FIG. 9) substantially annular slits 52 are formed in the resolver stator core 25 and the resolver rotor core 42 when viewed from the axial direction, and these slits 52 are concentric. May be arranged.

As shown in FIG. 10, a plurality of (for example, two in FIG. 10) substantially annular slits 53 are formed in the resolver stator core 25 and the resolver rotor core 42 when viewed from the axial direction, and a plurality of slits 53 are formed along the radial direction. (For example, four slits in FIG. 10) may be formed. The vertical slit 54 is formed around an arbitrary straight line in the radial direction passing through the rotation axis of the rotation shaft 13.
In this way, by combining the slit 53 and the vertical slit 54, the path through which the eddy current U flows can be effectively cut off, and the eddy current U can be reduced.

  In order to prevent the magnetic resistance of the resolver stator core 25 and the resolver rotor core 42 from increasing, the area of the core, which is reduced by providing the slit, should be minimized, and the slit width is preferably narrow. For example, when the resolver stator core 25 and the resolver rotor core 42 are made of a thin steel plate, the thickness is desirably 1.5 times or less the plate thickness. On the other hand, in consideration of mass-production processing technology, the slit width should be at least half of the plate thickness. Examples of the production method include laser processing, etching, and press processing.

FIG. 11 is a diagram in which the stator transformer coil 30 and the sin excitation coil 31 are projected on the resolver stator core 25 shown in FIG. In FIG. 11, the stator transformer coil 30 and the sin excitation coil 31 are shown by two-dot chain lines for easy understanding.
As shown in FIG. 11, by combining the slit 53 and the vertical slit 54, the flow of the eddy current U can be inhibited in the generation region R of the eddy current U (see FIG. 7) on the resolver stator core 25. In order to more effectively inhibit the flow of the eddy current U, the substantially annular slit 53 is arranged so as to overlap a part of each of the coils 30 and 31. The resolver rotor core 42 has the same effect.

  As shown in FIG. 12, a plurality of inner slits 38 and outer slits 39 formed in the resolver stator core 25 and the resolver rotor core 42 may be arranged so as to become denser toward the magnetic pole center C. That is, the interval between the inner slit 38 and the outer slit 39 may be narrower toward the magnetic pole center C, and may be wider as the distance from the magnetic pole center C increases. At the magnetic pole center C, the number of turns of the spiral coils 33 to 36, 46, and 47 increases, so that the generation of the eddy current U tends to increase. For this reason, by making the slits 38 and 39 denser toward the magnetic pole center C, the path through which the eddy current U flows can be more efficiently cut while ensuring sufficient mechanical strength of the cores 25 and 42. be able to.

Here, the magnetic pole center C will be described in detail.
As shown in FIG. 6, the detection coil 45 has two poles. That is, the detection coil 45 includes two spiral coils 46 and 47 having a substantially semicircular shape when viewed from the axial direction. The circumferential center of these two spiral coils 46 and 47 is the magnetic pole center C of the resolver rotor core 42 (detection coil 45).

  On the other hand, as shown in FIGS. 3A and 3B, the excitation coil 29 includes a sin excitation coil 31 shifted by 90 ° in mechanical angle and a cos excitation coil 32. That is, there are two magnetic pole centers Csin and Ccos, that is, the magnetic pole center Csin of the sin exciting coil 31 and the magnetic pole center Ccos of the cos exciting coil 32, and the two magnetic pole centers Csin and Ccos are shifted by 90 ° in mechanical angle. ing. In such a case, the magnetic pole center C of the resolver stator core 25 (exciting coil 29) is generated between the magnetic pole centers Csin and Ccos of the sin exciting coil 31 and the cos exciting coil 32, respectively. That is, the magnetic pole center C obtained by adding the sin exciting coil 31 and the cos exciting coil 32 becomes the magnetic pole center C of the resolver stator core 25 (the exciting coil 29). In the present embodiment, a position shifted by 45 ° in mechanical angle from the magnetic pole center Csin of the sin exciting coil 31 and the magnetic pole center Ccos of the cos exciting coil 32 becomes the magnetic pole center C of the resolver stator core 25 (the exciting coil 29). (FIGS. 3A and 3B show magnetic pole center lines connecting the magnetic pole centers). The concept of the magnetic pole center C is the same for the following modified examples.

  As shown in FIG. 13, a plurality of slits 51 formed over the entire radial direction of the resolver stator core 25 and the resolver rotor core 42 may be arranged so as to become denser toward the magnetic pole center C. That is, the circumferential interval of the slits 51 may be narrower toward the magnetic pole center C, and may be wider as the distance from the magnetic pole center C increases. With this configuration, it is possible to obtain the same effects as those of the above-described modification.

(2nd Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. Note that the same reference numerals are given to the same aspects as the first embodiment, and description thereof will be omitted.
FIG. 14 is a plan view of the resolver stator core 225 and the resolver rotor core 242 in the second embodiment as viewed from the axial direction.
In the second embodiment, the basic configuration of the brushless motor 1 is the same as that of the first embodiment. The basic configuration of the resolver 206 is the same as that of the first embodiment.

  Here, the difference between the first embodiment and the second embodiment is that the shapes of the resolver stator core 25 and the resolver rotor core 42 in the first embodiment, the resolver stator core 225 in the second embodiment, And the shape of the resolver rotor core 242 is different. Accordingly, the fixing directions of the resolver stator 221 and the resolver rotor 222 are different from those in the first embodiment. The details will be described below.

As shown in FIG. 14, the resolver stator core 225 and the resolver rotor core 242 in the second embodiment are formed in a substantially disc shape. However, an opening 25a (for example, see FIG. 2) through which the rotating shaft 13 (for example, see FIG. 1) can be inserted is not formed at substantially the center in the radial direction of the resolver stator core 225 and the resolver rotor core 242.
Therefore, although not particularly shown, the resolver rotor 222 is fixed to the other end 13 b of the rotating shaft 13. Further, the resolver stator 221 is arranged on the opposite side to the position of the resolver stator 21 in the above-described first embodiment. That is, the resolver stator 221 is disposed on the resolver rotor 222 on the side opposite to the motor stator 4. The resolver stator 221 is attached to a cover or the like (not shown) separately provided on the brushless motor 1.

  At a substantially radial center of the resolver stator core 225 and the resolver rotor core 242, a through-hole 61 penetrating in the thickness direction is formed. The through hole 61 is located radially inward of the stator transformer coil 30 and the rotor transformer coil 44 (see FIGS. 3A and 6, not shown in the second embodiment) when viewed from the axial direction.

  In the resolver stator core 225 and the resolver rotor core 242, a plurality of (for example, four in the second embodiment) inner slits extending radially outward from the inner peripheral edge of the through hole 61 and radially outward. 62 are formed. Further, the resolver stator core 225 and the resolver rotor core 242 have a plurality of (for example, four in the second embodiment) outer slits 63 extending radially inward and radially inward from the outer peripheral edges 225a and 242a. Is formed. The inner slits 62 and the outer slits 63 are alternately arranged at equal intervals in the circumferential direction.

  Even in the case of such a configuration, the same effects as those of the first embodiment can be obtained.

(Modification of the second embodiment)
In the above-described second embodiment, the case where the inner slit 62 and the outer slit 63 formed in the resolver stator core 225 and the resolver rotor core 242 are arranged at equal intervals in the circumferential direction has been described. However, the present invention is not limited to this, and the inner slit 62 and the outer slit 63 do not have to be arranged at equal intervals.
In the above-described first embodiment, the case where the number of each of the slits 62 and 63 is four has been described. However, the present invention is not limited to this, and the number of the slits 62 and 63 can be set arbitrarily.

  In the above-described second embodiment, a case has been described in which the through hole 61, the inner slit 62, and the outer slit 63 are formed in the resolver stator core 225 and the resolver rotor core 242 as means for inhibiting the flow of the eddy current U. However, the present invention is not limited to this, and slits may be formed in the resolver stator core 225 and the resolver rotor core 242 so as to obstruct the flow of the eddy current U. Hereinafter, a specific modification will be described with reference to FIGS. 15 to 17.

  For example, as shown in FIG. 15, a plurality of slits 64 formed over the entire radial direction are provided in the resolver stator core 225 and the resolver rotor core 242 so as to straddle between the through hole 61 and the outer peripheral edges 225a and 242a. You may. Each slit 64 is formed at equal intervals in the circumferential direction. However, the slits 64 need not be formed at equal intervals in the circumferential direction.

  Further, the slits 62, 63, and 64 of the second embodiment and the modified example described above may be arranged so as to be denser toward the magnetic pole center C. That is, the circumferential interval between the slits 62, 63, 64 may be narrower toward the magnetic pole center C, and may be wider as the distance from the magnetic pole center C increases.

  As shown in FIG. 16, a plurality of (for example, six in FIG. 16) substantially annular slits 65 are formed in the resolver stator core 225 and the resolver rotor core 242 when viewed from the axial direction, and these slits 65 are concentric. May be arranged.

As shown in FIG. 17, a plurality of (for example, three in FIG. 17) substantially annular slits 66 are formed in the resolver stator core 225 and the resolver rotor core 242 when viewed from the axial direction, and a plurality of slits 66 are formed along the radial direction. (For example, six slits in FIG. 17) may be formed. The vertical slit 67 is formed around an arbitrary radial line passing through the rotation axis of the rotation shaft 13.
In this way, by combining the slit 66 and the vertical slit 67, the path through which the eddy current U flows can be effectively cut off, and the eddy current U can be reduced. As a result, the slit width of the slit 66 can be increased.
In order to prevent the magnetic resistance of each core 225, 242 from increasing, the area of each core 225, 242, which is reduced by providing each slit 66, 67, should be minimized. A narrow one is desirable. For example, if each of the cores 225 and 242 is a thin steel plate, the thickness is desirably 0.5 to 1.5 times the plate thickness.

Note that the present invention is not limited to the above-described embodiment, and includes various modifications of the above-described embodiment without departing from the spirit of the present invention.
For example, in the above-described embodiment, the case has been described where the resolvers 6 and 206 are provided in the brushless motor 1 and are used to detect the rotational position of the motor rotor 5. However, the present invention is not limited to this, and the resolvers 6 and 206 can be used for various rotating electric machines.

  In the above-described embodiment, the slits 38, 39, 51 to 54, 62 to 67, and the through holes 61 are provided in the resolver stator cores 25 and 225 and the resolver rotor cores 42 and 242 as means for inhibiting the flow of the eddy current U. Has been described. These various slits 38, 39, 51 to 54, 62 to 67 and the through holes 61 may be combined as appropriate. The various slits 38, 39, 51 to 54, 62 to 67 and the through holes 61 are not limited to the above, and the electrical resistance is higher than the resolver stator cores 25 and 225 and the resolver rotor cores 42 and 242. It is only necessary that something that inhibits the flow is formed. The number of the various slits 38, 39, 51 to 54, 62 to 67 and the number of the through holes 61 are not limited to the numbers in the above embodiment.

  That is, for example, instead of the various slits 38, 39, 51 to 54, 62 to 67 and the through hole 61, a concave portion (for example, indicated by reference numeral 70 in FIG. 4) may be provided. By forming the concave portion 70, the thickness of the portion where the concave portion is formed is reduced, so that the electric resistance is higher than that of the portion where the concave portion 70 is formed. For this reason, the flow of the eddy current U can be inhibited by the recess 70. (For example, the slit 39 in FIG. 4 becomes a continuous thin portion, and becomes a recess with respect to the periphery.)

Further, the various slits 38, 39, 51 to 54, 62 to 67 and the through holes 61 may be filled with resin or the like. The mechanical strength of the resolver stator cores 25 and 225 and the resolver rotor cores 42 and 242 can be increased by the amount of resin or the like.
In addition, as long as the eddy current U is generated in the region R where the resolver stator cores 25 and 225 and the resolver rotor cores 42 and 242 are generated, any shape may be used as the resistance. Various shapes such as a U-shape and a V-shape can be adopted as viewed from the axial direction.

Further, in the above-described embodiment, various slits 38, 39 are provided at the positions where the exciting coil 29, the detecting coil 45, and the transformer coils 30, 44 of the resolver stator cores 25, 225 and the resolver rotor cores 42, 242 are formed. , 51 to 54, 62 to 67 and the case where the through holes 61 are formed have been described. However, the present invention is not limited to this. At least at the location where the exciting coils 29 of the resolver stator cores 25 and 225 are formed, the resistance (various slits 38, 39, 51 to 54, 62 to 62) that inhibits the flow of the eddy current U is provided. 67 and through holes 61).
If there is a resistance that inhibits the flow of the eddy current U at least at a position where the exciting coil 29 of the resolver stator cores 25 and 225 is formed, various slits 38 are provided in any one of the resolver stator cores 25 and 225 and the resolver rotor cores 42 and 242. , 39, 51 to 54, 62 to 67 and the through hole 61 may or may not be formed.

  Here, the eddy current U generated by energizing the exciting coil 29 tends to be larger than when energizing the other coils 30, 44, 45. For this reason, by providing a resistor at the position where the exciting coil 29 is arranged, the influence of the eddy current U is most easily reduced. Therefore, the detection accuracy of the rotational position of the motor rotor 5 by the resolvers 6, 206 can be effectively improved.

  In the above-described embodiment, the case has been described in which the excitation coil 29, the detection coil 45, and the transformer coils 30, 44 are formed by performing a film forming process or the like. However, the present invention is not limited to this, and the excitation coil 29, the detection coil 45, and the transformer coils 30, 44 can be formed by various methods. For example, a copper wire may be spirally laid on the second insulating sheet 27 or the third insulating sheet 43 to form the excitation coil 29, the detection coil 45, and the transformer coils 30, 44.

  In the above-described embodiment, the case where the stator transformer coil 30 is not formed on the back surface 27c of the second insulating sheet 27 and the cos exciting coil 31 is formed has been described. However, the present invention is not limited to this, and the stator transformer coil 130 may be formed on the back surface 27c of the second insulating sheet 27 as shown in FIG.

In this case, of the two terminal portions 30a and 30b of the stator transformer coil 30 formed on the surface 27b of the second insulating sheet 27, the radially inner terminal portion 30b (see FIG. 3A) and the second insulating sheet Of the two terminal portions 130a and 130b of the stator transformer coil 130 formed on the back surface 27c of the terminal 27, it is connected to the radially inner terminal portion 130b. Then, the control unit (in each case) connects the radially outer terminal portion 30a of the stator transformer coil 30 (see FIG. 3A) and the radially outer terminal portion 130a of the stator transformer coil 130 via a lead wire or the like. (Not shown).
With this configuration, electromagnetic induction between the stator transformer coils 30, 130 and the rotor transformer coil 44 can be further promoted. As a result, the detection accuracy of the rotational position of the motor rotor 5 by the resolver 6 can be further improved.

  In the above-described embodiment, the case where the rotor transformer coil 44 and the detection coil 45 are formed on the surface 43b of the third insulating sheet 43 has been described. However, the present invention is not limited to this. As shown in FIGS. 19 (a) and 19 (b), the rotor transformer coil 144 and the detector 43 are also provided on the back surface 43c opposite to the front surface 43b of the third insulating sheet 43. The coil 145 may be formed.

  In this case, on the front surface 43b of the third insulating sheet 43, the inner terminal portion 46b of one spiral coil 46 and the inner terminal portion 47b of the other spiral coil 47 are connected. The outer end portion 47a of the other spiral coil 47 is connected to the radially outer end portion 44a of the two end portions 44a and 44b of the rotor transformer coil 44 via a crossover portion 48. The radially inner terminal portion 44b of the rotor transformer coil 44 is connected to the radially outer terminal portion 144a of the two terminal portions 144a and 144b of the rotor transformer coil 144 formed on the back surface 43c of the third insulating sheet 43. ing.

  Also, on the back surface 43c of the third insulating sheet 43, the radially inner terminal portion 144b of both the terminal portions 144a and 144b of the rotor transformer coil 144 is the radially inner terminal portion 44b of the rotor transformer coil 44 on the front surface 43b. It is connected to the. One spiral coil 146 and the other spiral coil 147 are formed in a series. The one spiral coil 146 and the other spiral coil 147 are connected to one spiral coil 46 and the other spiral coil 47 of the corresponding surface 43b. Thereby, the rotor transformer coils 44 and 144 and the detection coils 45 and 145 form one closed circuit.

  With this configuration, electromagnetic induction between the stator transformer coils 30, 130 and the rotor transformer coils 44, 144 can be further promoted. As a result, the detection accuracy of the rotational position of the motor rotor 5 by the resolver 6 can be further improved.

In addition, the shapes of the excitation coil 29, the detection coil 45, and the transformer coils 30, 44 can be variously changed. For example, in the above-described embodiment, a case has been described in which the excitation coil 29 and the detection coil 45 have two poles. That is, the case where the excitation coil 29 and the detection coil 45 are constituted by the spiral coils 33 to 36, 46, and 47 formed in a substantially semicircular shape when viewed from the axial direction has been described. In addition, the case where the spiral coils 33 to 36, 46, and 47 are arranged symmetrically about an arbitrary straight line passing through the rotation axis of the rotation shaft 13 has been described. However, the present invention is not limited to this, and the number of poles of the exciting coil 29 and the detection coil 45 can be arbitrarily set. The excitation coil 29 and the detection coil 45 may be configured by two or more spiral coils.
The coils 29 and 45 are formed by etching a copper foil sheet formed on the insulating sheets 27 and 43, and by directly printing copper or silver on the insulating sheets 27 and 43 to form a pattern. Alternatively, a method of forming a coil with an electric wire may be used.

  In addition, the case where the sin excitation coil 31 and the cos excitation coil 32 are shifted by 90 ° in mechanical angle has been described. However, the present invention is not limited to this, and the deviation of the mechanical angle between the sin excitation coil 31 and the cos excitation coil 32 can be changed as appropriate according to the number of magnetic poles of the motor rotor 5. That is, the axial multiple angle of the resolver 6 is not limited to one, and is applicable to two or more.

  In the above-described embodiment, the excitation coils 29 of the resolver stators 21 and 221 are used for input. However, the present invention is not limited to this, and the stator transformer coils 30, 130 may be used for input. At this time, the input signal has one phase (for example, a sin-phase voltage signal), and the output signal has two phases (for example, a sin-phase and cos-phase voltage signal). For this reason, the excitation coil becomes a detection coil, and the detection coil becomes an excitation coil. Then, the rotation angles of the resolver rotors 22 and 222 with respect to the resolver stators 21 and 221 can be detected from the output two-phase signals.

6, 206 resolver, 21, 221 resolver stator, 22, 222 resolver rotor, 25, 225 resolver stator core (stator core), 25b one surface (first surface), 27 second insulating sheet, 29 excitation coil , 30, 130 ... stator transformer coil (first transformer coil), 31 ... sin excitation coil (excitation coil), 32 ... cos excitation coil (excitation coil), 38, 62 ... inner slit (resistance part), 39, 63 ... Outer slits (resistance portions), 42, 242: resolver rotor core (rotor core), 42a: one surface (second surface), 43: third insulating sheet, 44: rotor transformer coil (second transformer coil), 45: detection coil, 51, 52, 53, 64, 65, 66... Slit (resistor), 54, 67 .. vertical slit (slit), 61. Hole (resistance portion), 70 ... recess (resistance portion), R ... generation region, U ... eddy current

Claims (5)

A stator core,
A rotor core provided rotatably with respect to the stator core, and opposed to the stator core in a rotation axis direction;
A first transformer coil provided on the stator core;
A second transformer coil provided on the rotor core and facing the first transformer coil;
An exciting coil provided on the stator core and provided on a concentric circle with the first transformer coil;
A detection coil provided on the rotor core and facing the excitation coil;
With
At least one of the stator core and the rotor core, and at least a region overlapping a part of a place where the first transformer coil, the second transformer coil, the excitation coil, and the detection coil are arranged, A resolver comprising: a stator core; and at least one resistance portion that has a higher electrical resistance than the rotor core and that inhibits eddy current flow. The resolver according to claim 1, wherein the resistance portion is formed along a radial direction orthogonal to a rotation axis direction of the rotor core. 2. The resolver according to claim 1, wherein the resistance portion is formed so as to be curved along the rotation direction of the rotor core when viewed from a rotation axis direction. 3. The stator core and the rotor core are formed in a plate shape,
4. The resolver according to claim 1, wherein the resistance portion is a slit formed in at least one of the stator core and the rotor core. 5. 4. The resolver according to claim 1, wherein the resistance portion is a concave portion formed in at least one of the stator core and the rotor core. 5.

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