Patent ID: 12249876

DETAILED DESCRIPTION

Example embodiments will be described with reference to the drawings hereinafter.

It is to be noted that, in the present specification, a direction parallel to a central axis CA is referred to as an “axial direction”. In the axial directions, a direction from a first magnet16to a second magnet17described later is referred to as “one axial direction D1”, and a direction from the second magnet17to the first magnet16is referred to as “the other axial direction D2”. A direction orthogonal to the central axis CA is referred to as a “radial direction”, and a rotational direction about the central axis CA is referred to as a “circumferential direction Dr”. In the radial directions, a direction approaching the central axis CA is referred to as “radially inward”, and a direction away from the central axis CA is referred to as “radially outward”.

In the present specification, an “annular shape” includes not only a shape continuously connected without a cut over the entire region in the circumferential direction around a predetermined axis such as the central axis CA but also a shape having one or more cuts in a part of the entire region around the predetermined axis. In addition, a shape that draws a closed curve around a predetermined axis in a curved surface intersecting with the predetermined axis is also included.

In addition, in a positional relationship between any one of an azimuth, a line, and a plane and another, “parallel” includes not only a state in which both of them do not intersect at all no matter how long they extend, but also a state in which they are substantially parallel. In addition, “perpendicular” and “orthogonal” include not only a state in which both of them intersect each other at 90 degrees, but also a state in which they are substantially perpendicular and a state in which they are substantially orthogonal. In other words, each of “parallel”, “perpendicular”, and “orthogonal” includes a state in which the positional relationship between the two of them permits an angular deviation to a degree not departing from the spirit of the present disclosure.

It is to be noted that the above names are names used merely for description, and are not intended to limit actual positional relationships, directions, names, and the like.

FIG.1is a sectional view illustrating a configuration example of a motor100according to the present example embodiment. Each ofFIGS.2and3illustrates another configuration example of the motor100.FIG.2is a sectional view illustrating the configuration example of the motor100according to a first modification.FIG.3is a sectional view illustrating the configuration example of the motor100according to a second modification.

The motor100includes a rotor1, a stator2, a stator holder3, a substrate4, a magnetic sensor5, and an encoder6.

The rotor1is rotatable about the central axis CA extending in the axial direction. As described above, the motor100includes the rotor1. The rotor1has a shaft10, a rotor hub11, a rotor tube portion12, a flange portion13, a circumferential wall portion14, a yoke15, the first magnet16, the second magnet17, and a spacer18.

The shaft10has a columnar shape extending in the axial direction along the central axis CA.

The rotor hub11is fixed to an end portion on the other axial direction D2side of the shaft10. The rotor hub11has a disk shape surrounding the shaft10, and expands radially outward from a radially outer end portion of the shaft10.

The rotor tube portion12extends in the axial direction and surrounds the central axis CA. As described above, the rotor1includes the rotor tube portion12. In detail, the rotor tube portion12has a tubular shape surrounding the stator2and extends in the one axial direction D1from a radially outer end portion of the rotor hub11.

The flange portion13expands radially outward from an end portion on the one axial direction D1side of the rotor tube portion12and extends in the circumferential direction Dr.

The circumferential wall portion14extends in the one axial direction D1from a radially outer end portion of the flange portion13and extends in the circumferential direction Dr.

In the present example embodiment, the rotor hub11, the rotor tube portion12, the flange portion13, and the circumferential wall portion14are integrated. Materials of the above components are, for example, lightweight metals such as aluminum (Al). It is to be noted that the present disclosure is not limited to the example of the present example embodiment, and at least a portion of the above components may be a member different from the other portion.

The yoke15is disposed on a radially inner side surface of the rotor tube portion12. A magnetic material such as iron is used as a material of the yoke15. In the present example embodiment, the yoke15has a tubular shape extending in the axial direction. In the present example embodiment, a position in the axial direction of an end portion on the one axial direction D1side of the yoke15is the one axial direction D1with respect to an end portion on the one axial direction D1side of the first magnet16. However, the present disclosure is not limited to the above example, and the position in the axial direction of the end portion on the one axial direction D1side of the yoke15may be the same as the position of the end portion on the one axial direction D1side of the first magnet16, or may be the other axial direction D2than the position of the end portion on the one axial direction D1side of the first magnet16. It is to be noted that the present disclosure is not limited to the example of the first example embodiment, and the yoke15may be omitted.

The first magnet16is disposed on a radially inner side surface of the yoke15and faces the stator2in the radial direction. As described above, the rotor1has the first magnet16. In the present example embodiment, the first magnet16of the rotor1is disposed radially outward with respect to a stator core21of the stator2described later. That is, the motor100according to the present example embodiment is an outer rotor type. The yoke15is disposed on an end portion (for example, a radially outer end portion) opposite to the stator core21in the radial direction of the first magnet16. As described above, the rotor1has the yoke15.

In the first magnet16, magnetic poles different from each other (that is, the N pole and the S pole) are alternately arranged in the circumferential direction Dr. In the present example embodiment, the first magnet16has a plurality of magnet pieces160magnetized in the radial direction. The plurality of magnet pieces160are arranged in the circumferential direction Dr and surround the central axis CA. However, the present disclosure is not limited to the above example, and the first magnet16may be a single member surrounding the central axis CA.

The second magnet17is disposed on an end surface (for example, the radially inner side surface) on the stator core21side in the radial direction of the rotor tube portion12. The second magnet17is disposed on the one axial direction D1with respect to the first magnet16and the stator core21. The rotor1has the second magnet17. For example, as illustrated inFIG.1, the second magnet17is disposed with a gap from the first magnet16in the axial direction.

In the second magnet17, magnetic poles different from each other (that is, the N pole and the S pole) are alternately arranged in the circumferential direction Dr. In the present example embodiment, the second magnet17has a plurality of magnet pieces170magnetized in the axial direction. The plurality of magnet pieces170are arranged in the circumferential direction Dr and surround the central axis CA. However, the present disclosure is not limited to the above example, and the second magnet17may be a single member surrounding the central axis CA.

The spacer18is disposed between the first magnet16and the second magnet17in the axial direction. As described above, the rotor1has the spacer18. The spacer18is a non-magnetic material. Although the material of the spacer18is resin in the present example embodiment, the material may be, for example, lightweight non-magnetic metal such as Al. Since the spacer18between the first magnet16and the second magnet17is made of the non-magnetic material, weight of the motor100is further reduced as compared with a configuration in which the spacer18is made of the magnetic material.

In the present example embodiment, the spacer18is a member different from the rotor tube portion12, is disposed on the radially inner side surface of the rotor tube portion12, and extends in the circumferential direction Dr. However, the present disclosure is not limited to the above example, and the spacer18may be integrated with the rotor tube portion12as illustrated inFIG.2. For example, a protruding portion121protruding toward the stator core21side in the radial direction is disposed on an end portion on the stator core21side in the radial direction of the rotor tube portion12. The protruding portion121is used as the spacer18. InFIG.2, the spacer18is the protruding portion121protruding radially inward on a radially inner side portion of the rotor tube portion12and extends in the circumferential direction Dr.

In this way, since the number of components of the motor100is decreased, the number of manufacturing processes and a manufacturing cost of the motor100is reduced. Consequently, productivity of the motor100is improved. In addition, for example, when the second magnet17is directly disposed on the end portion (for example, a radially inner end portion) on the stator core21side in the radial direction of the rotor tube portion12, the radial size of the second magnet17is further increased as compared with a configuration in which the second magnet17is disposed on the rotor tube portion12via a member such as the yoke15. Consequently, a magnetic force of the second magnet17is made to be stronger, and detection accuracy of the magnetic sensor5is improved. Alternatively, the axial size of the second magnet17is further reduced, while the reduction in the magnetic force being suppressed or prevented.

Preferably, an end portion on the stator core21side in the radial direction of the spacer18is at the same radial position as an end portion on the stator core21side in the radial direction of the first magnet16, or at a position opposite to the stator core21in the radial direction with respect to the end portion on the stator core21side in the radial direction of the first magnet16. For example, although the radial position of a radially inner end portion of the spacer18is the same as the radial position of a radially inner end portion of the first magnet16in the present example embodiment, the radial position of the radially inner end portion of the spacer18may be located radially outward with respect to the radially inner end portion of the first magnet16. In this way, interference of the spacer18with the stator2is prevented. For example, when the motor100is assembled, the stator2is prevented from hitting the spacer18, so that the motor100is easily assembled. Consequently, the productivity of the motor100is improved due to an improvement of manufacturing efficiency. However, the above example does not exclude a configuration in which the end portion on the stator core21side in the radial direction of the spacer18is located at a position on the stator core21side in the radial direction with respect to the end portion on the stator core21side in the radial direction of the first magnet16. In this case, it is sufficient that the stator2does not interfere with the spacer18. For example, the configuration in which the radial position of the radially inner end portion of the spacer18is located radially inward with respect to the radially inner end portion of the first magnet16is not excluded.

In the present example embodiment, an end portion on the other axial direction D2side of the spacer18is in contact with the end portion on the one axial direction D1side of the yoke15. As a result, when assembling the rotor1, an axial position of the spacer18is easily determined.

FIGS.4A and4Bare enlarged views of a contact portion between the yoke15and the spacer18as viewed from the radial direction.FIG.4Ais the view illustrating a configuration example of the end portion on the one axial direction D1side of the yoke15and the end portion on the other axial direction D2side of the spacer18.FIG.4Bis the view illustrating another configuration example of the end portion on the one axial direction D1side of the yoke15and the end portion on the other axial direction D2side of the spacer18.

InFIGS.4A and4B, one member of the yoke15and the spacer18preferably has a first recess191. Further, the other member of the yoke15and the spacer18has a first protrusion192. In the configurations illustrated inFIGS.4A and4B, the one member described above is referred to as a “first assembly”, and the other member describe above is referred to as a “second assembly”. The first recess191is recessed from the second assembly toward the first assembly. The first protrusion192protrudes from the second assembly toward the first assembly and is fitted in the first recess191. Each of the first recess191and the first protrusion192may be singular or plural and arranged in the circumferential direction Dr.

For example, inFIG.4A, the spacer18is the first assembly described above, and has the first recess191. The first recess191is disposed on the end portion on the other axial direction D2side of the spacer18and is recessed in the one axial direction D1. The yoke15is the second assembly described above and has the first protrusion192. The first protrusion192is disposed on the end portion on the one axial direction D1side of the yoke15and protrudes in the one axial direction D1.

InFIG.4B, the yoke15is the first assembly described above and has the first recess191. The first recess191is disposed on the end portion on the one axial direction D1side of the yoke15and is recessed in the other axial direction D2. In addition, the spacer18is the second assembly described above and has the first protrusion192. The first protrusion192is disposed on the end portion on the other axial direction D2side of the spacer18and protrudes in the other axial direction D2.

As described above, since the first protrusion192is fitted into the first recess191at the contact portion between the end portion on the one axial direction D1side of the yoke15and the end portion on the other axial direction D2side of the spacer18, positioning of the spacer18in the circumferential direction Dr is easily performed.

It is to be noted that the above-described example does not exclude a configuration in which a fitting structure of the first recess191and the first protrusion192is not disposed at the contact portion with the yoke15and the spacer18. For example, each of the end portion on the one axial direction D1side of the yoke15and the end portion on the other axial direction D2side of the spacer18may be flat.

In addition, the above-described example does not exclude a configuration in which the end portion on the other axial direction D2side of the spacer18does not come into contact with the end portion on the one axial direction D1side of the yoke15.

The present disclosure is not limited to the example of the present example embodiment, and the end portion on the other axial direction D2side of the spacer18may be in contact with the end portion on the one axial direction D1side of the first magnet16. Even in this case, the axial position of the spacer18is easily determined when the rotor1is assembled.

FIGS.5A and5Bare enlarged views of a contact portion between the first magnet16and the spacer18as viewed from the radial direction.FIG.5Ais the view illustrating a configuration example of the end portion on the one axial direction D1side of the first magnet16and the end portion on the other axial direction D2side of the spacer18.FIG.5Bis the view illustrating another configuration example of the end portion on the one axial direction D1side of the first magnet16and the end portion on the other axial direction D2side of the spacer18.

InFIGS.5A and5B, one member of the first magnet16and the spacer18preferably has the first recess191. The other member of the first magnet16and the spacer18has the first protrusion192. In the configurations illustrated inFIGS.5A and5B, the one member described above is referred to as the “first assembly”, and the other member describe above is referred to as the “second assembly”. The first recess191is recessed from the second assembly toward the first assembly. The first protrusion192protrudes from the second assembly toward the first assembly and is fitted in the first recess191. Each of the first recess191and the first protrusion192may be singular or plural and arranged in the circumferential direction Dr.

For example, inFIG.5A, the spacer18is the first assembly described above, and has the first recess191. The first recess191is disposed on the end portion on the other axial direction D2side of the spacer18and is recessed in the one axial direction D1. In addition, the first magnet16is the second assembly described above and has the first protrusion192. The first protrusion192is disposed on the end portion on the one axial direction D1side of the first magnet16and protrudes in the one axial direction D1.

InFIG.5B, the first magnet16is the first assembly described above and has the first recess191. The first recess191is disposed on the end portion on the one axial direction D1side of the first magnet16and is recessed in the other axial direction D2. In addition, the spacer18is the second assembly described above and has the first protrusion192. The first protrusion192is disposed on the end portion on the other axial direction D2side of the spacer18and protrudes in the other axial direction D2.

As described above, since the first protrusion192is fitted into the first recess191at the contact portion between the end portion on the one axial direction D1side of the first magnet16and the end portion on the other axial direction D2side of the spacer18, the positioning of the spacer18in the circumferential direction Dr is easily performed.

In the present example embodiment, as described above, the first magnet16has the plurality of magnet pieces160arranged in the circumferential direction Dr. Consequently, the first recess191or the first protrusion192arranged at the end portion on the one axial direction D1side of the first magnet16may be formed by arrangement in the axial direction of the end portion on the one axial direction D1side of each of the magnet pieces160.

For example, the first magnet16has a first magnet piece161to a third magnet piece163arranged in order in the circumferential direction Dr. The plurality of magnet pieces160include the first magnet piece161to the third magnet piece163. An end portion on the one axial direction D1side of the second magnet piece162is located at the above-described first assembly side in the axial direction with respect to an end portion on the one axial direction D1side of the first magnet piece161and an end portion on the one axial direction D1side of the third magnet piece163. For example, when the first magnet16has the first protrusion192as illustrated inFIG.5A, the end portion on the one axial direction D1side of the second magnet piece162is located at the one axial direction D1with respect to the end portions on the one axial direction D1side of the first magnet piece161and the third magnet piece163. For example, when the first magnet16has the first recess191as illustrated inFIG.5B, the end portion on the one axial direction D1side of the second magnet piece162is located at the other axial direction D2with respect to the end portions on the one axial direction D1side of the first magnet piece161and the third magnet piece163. That is, the first recess191or the first protrusion192is formed by the arrangement of each of the end portions on the one axial direction D1side of the first magnet piece161to the third magnet piece163. Consequently, for example, the first recess191or the first protrusion192is easily formed as compared with a configuration in which the first recess191or the first protrusion192is formed in the single first magnet16.

It is to be noted that the above-described example does not exclude a configuration in which the first recess191or the first protrusion192arranged in the first magnet16is not dependent on the arrangement in the axial direction of the end portions on the one axial direction D1side of the plurality of magnet pieces160arranged in the circumferential direction Dr. For example, the first recess191or the first protrusion192may be disposed on the end portion on the one axial direction D1side of the first magnet16that is the single member.

It is to be noted that the above-described example does not exclude a configuration in which a fitting structure of the first recess191and the first protrusion192is not disposed at the contact portion with the first magnet16and the spacer18. For example, each of the end portion on the one axial direction D1side of the first magnet16and the end portion on the other axial direction D2side of the spacer18may be flat.

In addition, the above-described example does not exclude a configuration in which the end portion on the other axial direction D2side of the spacer18does not come into contact with the end portion on the one axial direction D1side of the first magnet16.

Then, an end portion on the one axial direction D1side of the spacer18is in contact with an end portion on the other axial direction D2side of the second magnet17. As a result, when assembling the rotor1, an axial position of the second magnet17is easily determined.

FIGS.6A and6Bare enlarged views of a contact portion between the second magnet17and the spacer18as viewed from the radial direction.FIG.6Ais the view illustrating a configuration example of the end portion on the other axial direction D2side of the second magnet17and the end portion on the one axial direction D1side of the spacer18.FIG.6Bis the view illustrating another configuration example of the end portion on the other axial direction D2side of the second magnet17and the end portion on the one axial direction D1side of the spacer18.

InFIGS.6A and6B, one member of the second magnet17and the spacer18preferably has a second recess193. In the configurations illustrated inFIGS.6A and6B, the one member described above is referred to as a “third assembly”. The other member of the second magnet17and the spacer18has a second protrusion194. In the configurations illustrated inFIGS.6A and6B, the other member described above is referred to as a “fourth assembly”. The second recess193is recessed from the fourth assembly toward the third assembly. The second protrusion194protrudes from the fourth assembly toward the third assembly and is fitted into the second recess193. Each of the second recess193and the second protrusion194may be singular or plural and arranged in the circumferential direction Dr.

For example, inFIG.6A, the spacer18is the third assembly described above, and has the second recess193. The second recess193is disposed on the end portion on the one axial direction D1side of the spacer18and is recessed in the other axial direction D2. The second magnet17is the fourth assembly described above and has the second protrusion194. The second protrusion194is disposed on the end portion on the other axial direction D2side of the second magnet17and protrudes in the other axial direction D2.

InFIG.6B, the second magnet17is the third assembly described above and has the second recess193. The second recess193is disposed on the end portion on the other axial direction D2side of the second magnet17and is recessed in the one axial direction D1. The spacer18is the fourth assembly described above and has the second protrusion194. The second protrusion194is disposed on the end portion on the one axial direction D1side of the spacer18and protrudes in the one axial direction D1.

As described above, since the second protrusion194is fitted into the second recess193at the contact portion between the end portion on the other axial direction D2side of the second magnet17and the end portion on the one axial direction D1side of the spacer18, positioning of the second magnet17in the circumferential direction Dr is easily performed.

In the present example embodiment, as described above, the second magnet17has the plurality of magnet pieces170arranged in the circumferential direction Dr. Consequently, the second recess193or the second protrusion194arranged at the end portion on the other axial direction D2side of the second magnet17may be formed by arrangement in the axial direction of the end portion on the other axial direction D2side of each of the magnet pieces170.

For example, the second magnet17has a fourth magnet piece171to a sixth magnet piece173arranged in order in the circumferential direction Dr. The plurality of magnet pieces170include the fourth magnet piece171to the sixth magnet piece173. An end portion on the other axial direction D2side of the fifth magnet piece172is located at the above-described third assembly side in the axial direction with respect to an end portion on the other axial direction D2side of the fourth magnet piece171and an end portion on the other axial direction D2side of the sixth magnet piece173. For example, when the second magnet17has the second protrusion194as illustrated inFIG.6A, the above-described third assembly having the second recess193is the spacer18. In this case, the end portion on the other axial direction D2side of the fifth magnet piece172is located at the other axial direction D2with respect to the end portions on the other axial direction D2side of the fourth magnet piece171and the sixth magnet piece173. When the second magnet17has the second recess193as illustrated inFIG.6B, the above-described third assembly having the second recess193is the second magnet17. In this case, the end portion on the other axial direction D2side of the fifth magnet piece172is located at the one axial direction D1with respect to the end portions on the other axial direction D2side of the fourth magnet piece171and the sixth magnet piece173. That is, the second recess193or the second protrusion194is formed by the arrangement of each of the end portions on the other axial direction D2side of the fourth magnet piece171to the sixth magnet piece173. Consequently, the second recess193or the second protrusion194is easily formed as compared with a configuration in which the second recess193or the second protrusion194is formed, for example, in the single second magnet17.

Axial positions of end portions on the one axial direction D1side of the plurality of magnet pieces170are preferably the same. For example, the axial positions of the end portions on the one axial direction D1side of the fourth magnet piece171to the sixth magnet piece173are the same. In this case, in the second magnet17, magnetic poles different from each other (the N pole, the S pole) are preferably arranged in the axial direction. The magnetic sensor5is disposed on the one axial direction D1with respect to the second magnet17. At least a part of the magnetic sensor5is further preferably superimposed on the second magnet17in the axial direction. Since the axial positions of the end portions on the one axial direction D1side of the fourth magnet piece171to the sixth magnet piece173are made to be the same, magnetic flux densities of the fourth magnet piece171to the sixth magnet piece173passing through the magnetic sensor5become stronger. Consequently, the detection accuracy of the magnetic sensor5is improved. However, the above example does not exclude a configuration in which the axial positions of the end portions on the one axial direction D1side of at least one part of the plurality of magnet pieces170are different from the axial positions of the end portions on the one axial direction D1side of another part.

It is to be noted that the above-described example does not exclude a configuration in which the second recess193or the second protrusion194arranged in the second magnet17is not dependent on the arrangement in the axial direction of the end portions on the other axial direction D2side of the plurality of magnet pieces170arranged in the circumferential direction Dr. For example, the second recess193or the second protrusion194may be disposed on the end portion on the other axial direction D2side of the second magnet17that is the single member.

Further, the present disclosure is not limited to the above-described example, and the fitting structure of the second recess193and the second protrusion194may not be disposed at the contact portion with the second magnet17and the spacer18. For example, each of the end portion on the other axial direction D2side of the second magnet17and the end portion on the one axial direction D1side of the spacer18may be flat.

In addition, the above-described example does not exclude a configuration in which the end portion on the one axial direction D1side of the spacer18does not come into contact with the end portion on the other axial direction D2side of the second magnet17.

The stator2rotationally drives the rotor1in accordance with supply of electric power. The stator2has the annual stator core21. The stator core21surrounds the central axis CA extending in the axial direction. The stator core21is a magnetic material, and is a laminated body in which electromagnetic steel plates are laminated in the axial direction in the present example embodiment. The stator2further has coil portions22. Each of the coil portions22is a member in which a coil-shaped conducting wire is disposed on the stator core21. When a driving current is supplied to each of the coil portions22, the stator2is excited and drives the rotor1. The conducting wire is, for example, an enamel-coated copper wire, a metal wire coated with an insulating member, or the like, and is wound around a tooth (not illustrated) of the stator core21via an insulator (not illustrated) to form the coil portion22.

The stator holder3holds the stator2. As described above, the motor100includes the stator holder3. The stator holder3has a holder tube portion31and a base portion32. The holder tube portion31has a tube shape surrounding the central axis CA and extends in the axial direction. The stator core21is fixed to a radially outer side surface of the holder tube portion31. Bearings311are disposed inside the holder tube portion31, and the shaft10is inserted through the bearings311. The holder tube portion31rotatably supports the shaft10via the bearings311. The base portion32is disposed on the one axial direction D1with respect to the rotor1and the stator2, and expands radially outward from an end portion on the one axial direction D1side of the holder tube portion31. A radially outside portion of the base portion32faces the flange portion13and the circumferential wall portion14of the rotor1in the axial direction.

Various electronic components such as a driving device of the stator2are mounted on the substrate4. The substrate4expands radially outward and extends in the circumferential direction Dr. The substrate4is disposed on an end surface on the other axial direction D2side of the base portion32.

The magnetic sensor5detects the magnetic force of the second magnet17. As described above, the motor100includes the magnetic sensor5. The motor100detects a rotation angle of the rotor1and so on based on a detection result of the magnetic sensor5. The magnetic sensor5is a Hall element in the present example embodiment. InFIGS.1and2, the magnetic sensor5is disposed on the one axial direction D1with respect to the second magnet17, and is mounted on the substrate4. At least a part of the magnetic sensor5is superimposed on the second magnet17in the axial direction. The magnetic sensor5may be singular or plural and arranged in the circumferential direction Dr.

It is to be noted that the arrangement of the magnetic sensor5is not limited to the examples inFIGS.1and2. For example, the magnetic sensor5may be disposed on the stator holder3. As an example, as illustrated inFIG.3, the magnetic sensor5may be disposed on the radially outer side surface of the holder tube portion31. The magnetic sensor5preferably faces the second magnet17in the radial direction. For example, at least a part of the magnetic sensor5is superimposed on the second magnet17in the radial direction. In this case, in the second magnet17, magnetic poles different from each other (the N pole, the S pole) are preferably arranged in the radial direction. That is, the second magnet17is magnetized in the radial direction. In this way, the magnetic sensor5is disposed in a vacant space in the one axial direction D1side with respect to the stator2. Consequently, since it is not necessary to secure a space for disposing the magnetic sensor5in the one axial direction D1side with respect to the second magnet17, there is a contribution to miniaturization of the motor100. In particular, the axial size of the motor100is reduced as compared with a configuration in which the magnetic sensor5faces the second magnet17in the axial direction.

The encoder6detects the rotation angle of the rotor1. The encoder6is mounted on the substrate4and is disposed radially outward with respect to the magnetic sensor5. The encoder6faces the flange portion13of the rotor1in the axial direction.

A second example embodiment will be described hereinafter. Configurations of the second example embodiment different from those of the first example embodiment and the modifications of the first example embodiment described above will be described. Constituent elements similar to those in the first example embodiment and the modification of the first example embodiment described above are denoted by the same reference numerals, and descriptions of the similar constituent elements may be omitted.

FIG.7is a sectional view illustrating a configuration example of the motor100according to the second example embodiment. As illustrated inFIG.7, the second magnet17is disposed on the end portion (for example, the radially inner end portion) on the stator core21side in the radial direction of the rotor tube portion12. As a result, the radial size of the second magnet17is further increased as compared with a configuration in which the second magnet17is disposed on the rotor tube portion12via a member such as the yoke15. Consequently, a magnetic force of the second magnet17is made to be stronger, and detection accuracy of the magnetic sensor5is improved. Alternatively, the axial size of the second magnet17is further reduced, while the reduction in the magnetic force being suppressed or prevented.

In addition, in the second example embodiment, as illustrated inFIG.7, the spacer18is not disposed in the rotor1. Instead, the end portion on the one axial direction D1side of the yoke15extends in the one axial direction D1with respect to the end portion on the one axial direction D1side of the first magnet16and is in contact with an end surface on the other axial direction D2side of the second magnet17. In this way, positioning of the second magnet17with respect to first magnet16in the axial direction is performed without disposing the spacer18. Since the spacer18is omitted, the weight of the motor100is further reduced. In addition, since the number of the components of the motor100is decreased, the number of the manufacturing processes and the manufacturing cost of the motor100is reduced. Consequently, productivity of the motor100is improved.

FIGS.8A and8Bare enlarged views of a contact portion between the yoke15and the second magnet17as viewed from the radial direction.FIG.8Ais the view illustrating a configuration example of the end portion on the one axial direction D1side of the yoke15and the end portion on the other axial direction D2side of the second magnet17.FIG.8Bis the view illustrating another configuration example of the end portion on the one axial direction D1side of the yoke15and the end portion on the other axial direction D2side of the second magnet17.

InFIGS.8A and8B, one member of the yoke15and the second magnet17preferably has the second recess193. The other member of the yoke15and the second magnet17has the second protrusion194. In the configuration illustrated inFIGS.8A and8B, the one member described above is referred to as the “third assembly”, and the other member described above is referred to as the “fourth assembly”. The second recess193is recessed from the fourth assembly toward the third assembly. The second protrusion194protrudes from the fourth assembly toward the third assembly and is fitted into the second recess193. Each of the second recess193and the second protrusion194may be singular or plural and arranged in the circumferential direction Dr.

The contact portion between the yoke15and the second magnet17is configured similarly to the contact portion between the second magnet17and the spacer18in the first example embodiment.

For example,FIG.8Ais configured similarly toFIG.6Aof the first example embodiment. In detail, the yoke15is the third assembly described above and has the second recess193. The second recess193is disposed on the end portion on the one axial direction D1side of the yoke15and is recessed in the other axial direction D2. The second magnet17is the fourth assembly described above and has the second protrusion194. The second protrusion194is disposed on the end portion on the other axial direction D2side of the second magnet17and protrudes in the other axial direction D2.

FIG.8Bis configured similarly toFIG.6Bof the first example embodiment. In detail, the second magnet17is the third assembly described above and has the second recess193. The second recess193is disposed on the end portion on the other axial direction D2side of the second magnet17and is recessed in the one axial direction D1. The yoke15is the fourth assembly described above and has the second protrusion194. The second protrusion194is disposed on the end portion on the one axial direction D1side of the yoke15and protrudes in the one axial direction D1.

As described above, since the second protrusion194is fitted into the second recess193at the contact portion between the end portion on the one axial direction D1side of the yoke15and the end portion on the other axial direction D2side of the second magnet17, the positioning of the second magnet17with respect to the yoke15in the circumferential direction Dr is easily performed.

As described above, the second magnet17has the plurality of magnet pieces170arranged in the circumferential direction Dr. Consequently, the second recess193or the second protrusion194arranged at the end portion on the other axial direction D2side of the second magnet17may be formed by arrangement in the axial direction of the end portion on the other axial direction D2side of each of the magnet pieces170.

It is to be noted that the above-described example does not exclude the configuration in which the second recess193or the second protrusion194arranged in the second magnet17is not dependent on the arrangement in the axial direction of the end portions on the other axial direction D2side of the plurality of magnet pieces170arranged in the circumferential direction Dr. For example, the second recess193or the second protrusion194may be disposed on the end portion on the other axial direction D2side of the second magnet17that is the single member.

Further, the present disclosure is not limited to the above-described example, and the fitting structure of the second recess193and the second protrusion194may not be disposed at the contact portion with the yoke15and the second magnet17. For example, each of the end portion on the one axial direction D1side of the yoke15and the end portion on the other axial direction D2side of the second magnet17may be flat.

In addition, the above-described example does not exclude a configuration in which the end portion on the other axial direction D2side of the second magnet17does not come into contact with the end portion on the one axial direction D1side of the yoke15.

The example embodiments of the present disclosure have been described above. It is to be noted that the scope of the present disclosure is not limited to the above-described example embodiments. The present disclosure is implemented by adding various modifications to the above-described example embodiments within a range not departing from the spirit of the disclosure. In addition, the matters described in the above-described example embodiments are arbitrarily combined together as appropriate within a range where no inconsistency occurs.

The present disclosure is useful for a device in which a magnet used in a pair with a magnetic sensor is disposed separately from a magnet for driving a rotor.

Features of the above-described preferred example embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.

While example embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.