WO2017175609A1

WO2017175609A1 - Motor, in-wheel motor, and wheel device

Info

Publication number: WO2017175609A1
Application number: PCT/JP2017/012108
Authority: WO
Inventors: 薫西口; 中村　学
Original assignee: ミネベアミツミ株式会社
Priority date: 2016-04-08
Filing date: 2017-03-24
Publication date: 2017-10-12
Also published as: JP6842838B2; JP2017185975A

Abstract

A motor (200) according to an embodiment is provided with: a stator (210); a rotor (220) that rotates relative to the stator (210) around a rotation axis; a shaft (211) disposed so as to extend in the axial direction of the rotation axis; and an angular sensor (212) for detecting a rotation angle of the rotor (220) with respect to the stator (210). The shaft (211) is fixed to one of the stator (210) and the rotor (220) and is disposed so as to oppose and be separated from the other of the stator (210) and the rotor (220) by a predetermined distance in the axial direction. The angular sensor (212) is disposed between an end section of the shaft (211) in the axial direction and a portion opposing the end section in the other of the stator (210) and the rotor (220).

Description

Motor, in-wheel motor and wheel device

The present invention relates to a motor, an in-wheel motor, and a wheel device.

Conventionally, an angle sensor for controlling the operation of a motor is generally provided in a motor used for driving various devices and various devices. The angle sensor detects a relative rotation angle between the stator and the rotor included in the motor. For example, an optical encoder, a resolver, or the like is used as the angle sensor. In recent years, devices using motors have been diversified, and therefore, there has been a demand for miniaturized motors with built-in angle sensors.

Japanese Patent Laid-Open No. 2015-89188 Japanese Patent No. 5615033 Japanese Patent No. 5517869

However, it has been difficult to incorporate the above-described conventional angle sensor in a small motor. For example, an optical encoder is difficult to incorporate in a motor due to heat resistance and shape problems. Moreover, it is difficult to reduce the size of the resolver because of the structure using a coil or the like, and it is difficult to incorporate the resolver in a small motor. For this reason, with the conventional technology, it has been difficult to realize a miniaturized motor while incorporating the angle sensor in the motor.

The present invention has been made in view of the above, and an object thereof is to provide a motor, an in-wheel motor, and a wheel device that can be miniaturized while incorporating an angle sensor.

In order to solve the above-described problems and achieve the object, a motor according to one aspect of the present invention includes a stator, a rotor that rotates relative to the stator about a rotation axis, and an axis of the rotation axis. A shaft disposed so as to extend in a direction; and an angle sensor that detects a rotation angle of the rotor with respect to the stator, wherein the shaft is fixed to one of the stator and the rotor, and the stator and the rotor The angle sensor is arranged to face the other end of the shaft in the axial direction with a predetermined distance therebetween, and the angle sensor faces the end in the axial direction of the shaft and the end of the other of the stator and the rotor. It is arranged between the parts to be.

According to one embodiment of the present invention, it is possible to realize a motor and an in-wheel motor that can be miniaturized while incorporating an angle sensor.

FIG. 1 is a perspective view showing an appearance of a wheel device incorporating an in-wheel motor according to the present embodiment. FIG. 2 is an exploded perspective view showing the configuration of the wheel device incorporating the in-wheel motor according to the present embodiment. FIG. 3 is an exploded cross-sectional perspective view showing the configuration of the wheel device incorporating the in-wheel motor according to the present embodiment. FIG. 4 is a cross-sectional perspective view showing a configuration of a stator included in the in-wheel motor according to the present embodiment. FIG. 5 is an exploded perspective view showing a configuration of a rotor included in the in-wheel motor according to the present embodiment. FIG. 6 is a front view showing the wheel device according to the present embodiment. FIG. 7 is a side sectional view showing the wheel device according to the present embodiment.

Hereinafter, the motor, the in-wheel motor, and the wheel device according to the embodiment will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a perspective view showing an appearance of a wheel device incorporating an in-wheel motor according to the present embodiment. The in-wheel motor which concerns on this embodiment is incorporated in the wheel apparatus 100 shown in FIG. 1, for example. The wheel device 100 is used as, for example, a drive wheel of a self-propelled robot or a transport cart.

For example, as shown in FIG. 1, the wheel device 100 includes a wheel 110 and a tire 120. The wheel 110 is a wheel formed in a substantially bottomed cylindrical shape using metal, plastic, or the like. The tire 120 is formed in a substantially annular shape using a material having elasticity such as rubber and is fixed so as to surround the wheel 110. For example, since the tire 110 is a consumable item, the wheel 110 and the tire 120 have a structure that can be exchanged in an integrated state with each as a basic configuration.

For example, the in-wheel motor according to the present embodiment is directly connected to the wheel 110 and rotates the wheel 110 about a predetermined rotation axis R. That is, the in-wheel motor according to the present embodiment is, for example, a direct drive type in-wheel motor.

FIG. 2 is an exploded perspective view showing the configuration of the wheel device 100 incorporating the in-wheel motor according to the present embodiment. For example, as shown in FIG. 2, the in-wheel motor 200 according to the present embodiment is mounted inside the wheel 110 of the wheel device 100 and is fixed to the bottom of the wheel 110 by a nut 111.

For example, the in-wheel motor 200 includes a stator 210, a rotor 220, and a cover 230. The stator 210 is fixed to a device on which the wheel device 100 is mounted via a shaft 211 arranged so as to extend in the axial direction of the rotation axis R.

The rotor 220 rotates relative to the stator 210 around the rotation axis R. Here, the rotor 220 has a casing 221 that accommodates the stator 210, is disposed so as to surround the outer periphery of the stator 210, and rotates along the outer periphery. That is, the in-wheel motor 200 according to the present embodiment is an outer rotor type motor.

The cover 230 has a through hole 231 formed therein, and seals the space in the housing 221 of the rotor 220 with the shaft 211 passing through the through hole 231. For example, the cover 230 is formed in a substantially disc shape, and a through hole 231 is provided in the approximate center. The cover 230 is fixed to the wheel 110 with, for example, screws 232 in a state where the stator 210 is housed in the housing 221 and the shaft 211 is passed through the through hole 231.

Here, the stator 210, the rotor 220, and the in-wheel motor 200 have a waterproof structure that prevents water from entering the casing 221 of the rotor 220. For example, the cover 230 includes an O-ring 233 and a rubber seal bearing 234. The O-ring 233 is disposed between the cover 230 and the casing 221 of the rotor 220, and seals between the two. The rubber seal bearing 234 rotatably supports the shaft 211 inside the through hole 231 of the cover 230 and seals between the through hole 231 and the shaft 211. Further, the screw 232 for fixing the cover 230 to the wheel 110 is waterproofed after being tightened.

FIG. 3 is an exploded cross-sectional perspective view showing the configuration of the wheel device 100 incorporating the in-wheel motor 200 according to the present embodiment. For example, as shown in FIG. 3, the in-wheel motor 200 includes an angle sensor 212 that detects a rotation angle of the rotor 220 with respect to the stator 210. Here, the angle sensor 212 is disposed between the axial end portion of the shaft 211 and the portion of the rotor 220 facing the end portion.

In the present embodiment, the angle sensor 212 is a magnetic sensor and detects the rotation angle of the rotor 220 with respect to the stator 210 by detecting the angular position of the sensor magnet 222 provided on the stator 210. To do. For example, the angle sensor 212 includes an IC (Integrated Circuit), detects an angular position of a magnet placed at a position facing the IC by an absolute angle or a relative angle, and outputs a three-phase control signal for the UVW phase. A high-speed rotation angle sensor capable of outputting is used.

FIG. 4 is a cross-sectional perspective view showing the configuration of the stator 210 provided in the in-wheel motor 200 according to the present embodiment. For example, as shown in FIG. 4, the stator 210 includes a shaft 211, an angle sensor 212, a stator base 213, a bearing 214, a stator core 215, and a substrate 216.

The stator base 213 is a support member disposed substantially at the center of the stator 210, and is formed in a substantially bottomed cylindrical shape. Here, the stator base 213 is disposed such that the central axis of the stator base 213 coincides with the rotation axis R.

The shaft 211 is formed in a hollow, substantially cylindrical shape, and is fixed in a state where one end is inserted into the inner peripheral side of the stator base 213. Here, the shaft 211 is fixed to the stator base 213 so that the central axis of the shaft 211 coincides with the central axis of the stator base 213.

The bearing 214 is fixed at a position separated from the outer bottom surface of the stator base 213 by a predetermined distance. Here, the bearing 214 is fixed to the stator base 213 so that the center axis of the bearing 214 coincides with the center axis of each of the stator base 213 and the shaft 211.

The stator core 215 has a laminated structure in which a plurality of plate-like soft magnetic materials are laminated in the axial direction of the stator base 213, and is fixed to the outer periphery of the stator base 213 and the outer periphery of the bearing 214. Here, a plurality of salient poles (not shown) are provided on the outer peripheral portion of the stator core 215 at substantially equal intervals along the circumferential direction. A coil is wound around each salient pole.

The substrate 216 is formed in a substantially disc shape and is fixed so as to be orthogonal to the central axis of the stator base 213. Here, the substrate 216 is disposed at a predetermined interval in the axial direction along the end surface of the stator core 215 on the side where the shaft 211 protrudes.

In this embodiment, the angle sensor 212 is fixed to the outer bottom surface of the stator base 213 so as to intersect the central axis of the stator base 213. As a result, the angle sensor 212 is disposed at a position facing the bearing hole of the bearing 214.

Further, in the present embodiment, the stator 210 further includes another angle sensor 217 that detects the rotation angle of the rotor 220 with respect to the stator 210, in addition to the angle sensor 212 described above. For example, as the angle sensor 217, an angle sensor using a Hall element or a Hall IC is used.

For example, three angle sensors 217 are provided on the surface of the substrate 216 on the side facing the stator core 215 by shifting the position by 120 ° in the circumferential direction. In FIG. 4, illustration of two of the three angle sensors 217 is omitted.

Thus, it becomes possible to have a redundant configuration in which a plurality of angle sensors are provided.

FIG. 5 is an exploded perspective view showing the configuration of the rotor 220 provided in the in-wheel motor 200 according to the present embodiment. For example, as illustrated in FIG. 5, the rotor 220 includes a housing 221 and a plurality of magnets 223.

The housing 221 is formed in a substantially bottomed cylindrical shape, and includes a rotor frame 221a serving as a peripheral wall and a rotor case 221b serving as a bottom. The rotor frame 221a is formed in a substantially cylindrical shape using a nonmagnetic material. The rotor case 221b is formed in a substantially disk shape using a nonmagnetic material. The rotor case 221b is provided with a plurality of protrusions 221c that are arranged in a comb shape in the circumferential direction along the end portions and protrude toward the side facing the rotor frame 221a.

The plurality of magnets 223 each have a strip shape, and are provided in the circumferential direction along the inner circumference of the rotor frame 221a in a magnetized state. When the rotor case 221b is attached to the rotor frame 221a, the protrusions 221c of the rotor case 221b are fitted in the gaps between the magnets 223, so that the positions of the magnets 223 in the circumferential direction of the rotor frame 221a. Fixed.

Also, these magnets 223 are arranged so as to face the stator core 215 when the stator 210 is incorporated inside the rotor 220. As a result, when a drive current is passed through the coil of the stator core 215, the rotor 220 rotates around the rotation axis R along the outer periphery of the stator 210 by the electromagnetic force generated in the coil.

In this embodiment, the rotor case 221b is provided with a rod-shaped rotor shaft 221d that protrudes along the rotation axis R toward the side facing the rotor frame 221a. Here, the aforementioned sensor magnet 222 is fixed to the tip of the rotor shaft 221d. The rotor shaft 221d is disposed so as to pass through the bearing hole of the bearing 214 provided in the stator 210 when the stator 210 is incorporated inside the rotor 220. As a result, the sensor magnet 222 fixed to the tip portion of the rotor shaft 221d is disposed to face the angle sensor 212.

FIG. 6 is a front view showing the wheel device 100 according to the present embodiment, and FIG. 7 is a side sectional view showing the wheel device 100 according to the present embodiment. FIG. 7 shows a cross-section at the position AA of the wheel device 100 shown in FIG.

For example, as shown in FIG. 7, in this embodiment, the shaft 211 is fixed to the stator 210 and disposed so as to face the rotor 220 with a predetermined distance D in the axial direction. The angle sensor 212 is disposed between the axial end portion of the shaft 211 and the portion of the stator 210 facing the end portion.

Specifically, the stator 210 and the rotor 220 are arranged such that the axial end portion of the shaft 211 on the stator 210 side and the tip end portion of the rotor shaft 221d are spaced apart by a distance D. An angle sensor 212 is provided at the end of the shaft 211 on the stator 210 side in the axial direction, and a sensor magnet 222 is provided at the tip of the rotor shaft 221d.

Here, the distance D is a distance according to the specification of the angle sensor 212. For example, when a magnetic sensor is used as the angle sensor 212 as in the present embodiment, the distance D is set so that the sensor magnet 222 is disposed within a range in which the angle sensor 212 can detect the rotation angle. Is done.

Thus, by arranging the axial end of the shaft 211 and the rotor 220 apart from each other by a predetermined distance D, a space for arranging the angle sensor 212 is secured inside the in-wheel motor 200. be able to. As a result, the in-wheel motor 200 can incorporate the angle sensor 212 without increasing the width of the in-wheel motor 200 in the axial direction (stacking direction of the stator core 215). In the present embodiment, such a configuration relating to the arrangement of the magnetic sensor makes it possible to realize an in-wheel motor that can be downsized while incorporating the angle sensor.

Further, in the present embodiment, the in-wheel motor 200 is connected to the conductor 241 connected to the stator 210 disposed in the space in the housing 221, the conductor 242 connected to the angle sensor 212, and the angle sensor 217. A conductive wire 243.

Here, the conducting wire 241 is a power supply line that supplies a driving current to the coil of the stator 210 from an external power supply device. The conducting wire 242 is a signal line that transmits a control signal output from the angle sensor 212 to an external control device. The conducting wire 243 is a signal line that transmits a control signal output from the angle sensor 217 to an external control device.

Then, the conducting wires 241 to 243 are wired from the space in the housing 221 to the outside of the cover 230 through the inside of the shaft 211. For example, each conducting wire is wired through a through hole 211 a provided in a part of the peripheral wall portion of the shaft 211. Here, the through hole 211 a is disposed between the stator core 215 and the cover 230 when the stator 210 is incorporated in the housing 221 and the cover 230 is attached to the housing 221 in the shaft 211. Provided in position.

In this way, by wiring each lead wire through the inside of the shaft 211, each lead wire is passed from the inside of the in-wheel motor 200 to the outside while the space in the housing 221 is kept sealed by the cover 230. Wiring becomes possible.

As described above, according to this embodiment, it is possible to realize an in-wheel motor that can be downsized while incorporating an angle sensor.

In the above-described embodiment, the example in which the in-wheel motor 200 includes the three angle sensors 217 in addition to the angle sensor 212 has been described, but the embodiment is not limited thereto. For example, when only the angle sensor 212 is sufficient for the angle detection sensor, the substrate 216 and the three angle sensors 217 may be omitted from the components of the in-wheel motor 200. In this case, since the width in the axial direction of the stator 210 can be further reduced by the amount excluding the substrate 216 and the three angle sensors 217, the in-wheel motor 200 can be further reduced in size.

In the above-described embodiment, the in-wheel motor has been described, but the embodiment is not limited thereto. The configuration related to the arrangement of the angle sensor described above can also be applied to other types of motors having a stator and a rotor.

In the above-described embodiment, the outer rotor type motor has been described, but the embodiment is not limited thereto. For example, the configuration related to the arrangement of the angle sensor described above can also be applied to an inner rotor type motor and an axial gap type motor.

For example, an inner rotor type motor includes a stator and a rotor that is disposed on the inner circumference side of the stator and rotates along the inner circumference of the stator. In this case, for example, the shaft is fixed to the rotor and arranged to face the stator with a predetermined distance in the axial direction. The angle sensor is disposed between an axial end portion of the shaft and a portion of the stator facing the end portion.

Further, for example, an axial gap type motor includes a stator and a rotor arranged to face each other in the axial direction of the rotation shaft. In this case, for example, the shaft is fixed to one of the stator and the rotor, and is disposed so as to face the other of the stator and the rotor with a predetermined distance in the axial direction. The angle sensor is disposed between an axial end portion of the shaft and a portion facing the end portion of the other of the stator and the rotor.

Regardless of the type of motor, the angle sensor is arranged inside the motor by placing the end of the shaft in the axial direction and the portion of the stator or rotor facing the end away from each other by a predetermined distance. Space can be secured. As a result, in any type of motor, it is possible to incorporate an angle sensor in the motor without increasing the axial width of the motor. That is, it is possible to realize a motor that can be downsized while incorporating an angle sensor.

Further, the present invention is not limited by the above embodiment. What comprised suitably combining each component mentioned above is also contained in this invention. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

DESCRIPTION OF SYMBOLS 110 Wheel 200 In-wheel motor 210 Stator 211 Shaft 212 Angle sensor 217 Angle sensor 220 Rotor 221 Case 222 Sensor magnet 230 Cover 241 to 243 Conductor

Claims

A stator,
A rotor that rotates relative to the stator about a rotation axis;
A shaft arranged to extend in the axial direction of the rotating shaft;
An angle sensor for detecting a rotation angle of the rotor with respect to the stator,
The shaft is fixed to one of the stator and the rotor, and is arranged to face the other of the stator and the rotor with a predetermined distance apart in the axial direction,
The angle sensor is disposed between the axial end of the shaft and a portion facing the end of the other of the stator and the rotor.
motor.
In addition to the angle sensor, the angle sensor further includes another angle sensor that detects a rotation angle of the rotor with respect to the stator.
The motor according to claim 1.
A housing that houses one of the stator and the rotor;
A cover for sealing a space in the housing in a state where a through hole is formed and the shaft is passed through the through hole;
One of the stator and the rotor, or a conductive wire connected to the angle sensor,
The conducting wire is wired out of the cover through the inside of the shaft from the space in the housing.
The motor according to claim 1 or 2.
The angle sensor is a magnetic sensor that is provided on one of the rotor and the stator and detects the rotation angle by detecting an angular position of a sensor magnet provided on the other of the rotor and the stator.
The motor according to claim 1 or 2.
The rotor is disposed so as to surround the outer periphery of the stator and rotates along the outer periphery.
The motor according to claim 1 or 2.
An in-wheel motor mounted inside the wheel,
A stator,
A rotor that rotates relative to the stator about a rotation axis;
A shaft arranged to extend in the axial direction of the rotating shaft;
An angle sensor for detecting a rotation angle of the rotor with respect to the stator,
The shaft is fixed to the stator and is arranged to face the rotor with a predetermined distance in the axial direction;
The angle sensor is disposed between an end of the shaft in the axial direction and a portion of the rotor facing the end.
In-wheel motor.
A wheel device incorporating the motor according to claim 1 or the in-wheel motor according to claim 6.