Motors and Rotating Equipment

Abstract

To improve the accuracy of detecting a rotation angle.SOLUTION: A motor according to an embodiment includes a shaft, a rotor supported by the shaft, a stator provided inside the rotor, a member opposed to the rotor in an axial direction of the shaft, and a sensor provided on the member. Further, the sensor has a light source for radially emitting light, and a light reception part for receiving the light from the light source. The rotor includes a light shielding part projected in the axial direction, a magnetic member having a tubular section and a top surface section, and a magnet fixed to the tubular section of the magnetic member. The sensor is disposed in a position sandwiching the light shielding part in a radial direction. In the axial direction, the magnet is opposed to the sensor. In a rotating state of the rotor, light going from the light source toward the light reception part is shielded by the light shielding part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a motor and a rotating device. [Background technology]

[0002] Conventionally, magnetic sensors such as Hall elements have been used to detect the rotation state of motors for control. The magnetic sensor detects the magnetic flux of a magnet attached to the rotor of the motor and outputs a signal corresponding to the rotation state of the motor.

[0003] On the other hand, an electric motor has been disclosed in which a reflecting plate is attached to the concentric circles of a multi-pole magnet or multiple reflective surfaces are created by deposition or the like, and the light emitting element and the light receiving element are arranged on the side of the multi-pole magnet having the reflective surface so that the light output from the light emitting element is reflected and enters the light receiving element (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 62-2845 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a magnetic sensor is used, for example, when the temperature of the rotor magnet becomes high, the magnetic flux density decreases, and it may be difficult for the magnetic sensor to detect the magnetic flux of the rotor magnet. Also, when a Hall element is used for the magnetic sensor, a high ambient temperature may change the performance of the Hall element, making it difficult to obtain a desired signal from the Hall element and making it difficult to detect the position of the rotor magnet.

[0006] In addition, the distance between the rotor magnet and the magnetic sensor must be kept to a certain degree because if they are too close, they may come into contact, and if the distance is long, the magnetic sensor may have difficulty detecting the magnetic flux of the rotor magnet. This can cause a discrepancy between the rotor rotation angle detected by the magnetic sensor and the actual rotor rotation angle.

[0007] The present invention addresses the above-mentioned problem as an example, and has an object to provide a motor that can improve the detection accuracy of a rotation angle. [Means for solving the problem]

[0008] A motor according to one aspect of the present invention includes a shaft and a rotor fixed to an outer circumferential surface of the shaft. Has an inner circumferential surface The rotor includes a magnetic body, a magnet fixed to an outer peripheral surface of the magnetic body, a stator surrounding the rotor, a member facing the rotor in the axial direction of the shaft, and a sensor provided on the member. The sensor has a light source that emits light in a radial direction, and a light receiving portion that receives light from the light source in the radial direction. The above The end of the magnetic body has one or more light-shielding parts protruding in the axial direction, the one or more light-shielding parts being formed of the magnetic body. The one or more light-shielding portions include, in the axial direction, a portion of the outer circumferential surface to which the magnet is fixed, and another portion of the outer circumferential surface. The sensor is disposed at a position on either side of the light blocking portion in the radial direction. When the rotor is rotating, the light from the light source to the light receiving portion is blocked by the light blocking portion.

[0009] A motor according to an aspect of the present invention can improve the detection accuracy of a rotation angle. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an external perspective view of a motor according to a first embodiment. [Diagram 2] FIG. 2 is a vertical sectional view of the motor according to the first embodiment. [Diagram 3] FIG. 3 is a perspective view of peripheral elements of the sensor in the first embodiment. [Figure 4]FIG. 4 is a diagram showing a state in which the rotor yoke is attached in the first embodiment. [Diagram 5] FIG. 5 is a view of the rotor yoke in the first embodiment as seen from another angle. [Figure 6] FIG. 6 is an external perspective view of the motor according to the second embodiment. [Figure 7] FIG. 7 is a vertical sectional view of the motor according to the second embodiment. [Figure 8] FIG. 8 is a diagram showing how the rotor yoke is attached in the second embodiment. [Figure 9] FIG. 9 is a view of the rotor yoke in the second embodiment as seen from another angle. [Figure 10] FIG. 10 is an external perspective view of a rotating device according to a third embodiment. [Figure 11] FIG. 11 is an exploded perspective view showing elements of a rotating device according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, motors according to embodiments will be described with reference to the drawings. Note that the present invention is not limited to these embodiments. Furthermore, the dimensional relationships and ratios of elements in the drawings may differ from the reality. The drawings may also include parts with different dimensional relationships and ratios. Furthermore, the contents described in one embodiment or modified example are, in principle, applicable to other embodiments or modified examples in the same manner.

[0012] (First embodiment) FIG. 1 is an external perspective view of a motor 100 according to a first embodiment, which is an example of an inner rotor type motor in which a rotor is provided inside the motor. In FIG. 1, the motor 100 includes a housing 118 and a shaft 104. The housing 118 is composed of a cylindrical tube portion 101 having a bottom portion on the upper side in the figure (one end side of the shaft 104), and a cover portion (102) that is not visible in FIG. 1 and covers an opening on the lower side in the figure of the tube portion 101 (the other end side of the shaft 104). The shaft 104 is rod-shaped and is exposed from the center of a protrusion portion 101a provided in the center of the upper end face in the figure of the tube portion 101. A power line (not shown) is connected to a wiring portion 101c provided on the outer circumferential surface (side surface) of the tube portion 101.

[0013] Fig. 2 is a vertical cross-sectional view of the motor 100 in the first embodiment. In Fig. 2, a lid portion 102 is fixed to cover a lower opening of the cylinder portion 101 in the figure. The lid portion 102 is an example of a base.

[0014] A cylindrical rotor yoke 105 made of a magnetic material is fixed (fitted) to the outer circumferential surface of the shaft 104. A ring-shaped magnet 106 is fixed (fitted) to the outer circumferential surface of the rotor yoke 105. The shaft 104, rotor yoke 105, and magnet 106 form the rotor 103. The rotor yoke 105 is an example of a magnetic member.

[0015] The shaft 104 is rotatably supported by an inner ring of a bearing 107, the outer ring of which is fitted to the inner surface (inner wall) of the protruding portion 101a of the cylindrical portion 101, and an inner ring of a bearing 108, the outer ring of which is fixed (fitted) to the inner surface (inner wall) of the protruding portion 102a of the cover portion 102. A hole 101b through which the shaft 104 passes is formed in the center of the protruding portion 101a in the radial direction. Also, a hole 102b is formed in the center of the protruding portion 102a in the radial direction.

[0016] Further, on the inner surface (inner wall) of the cylindrical portion 101, a core 112, a first insulator 113, a second insulator 114, and a coil 115 are provided. The core 112 is formed by laminating electromagnetic steel sheets. The first insulator 113 and the second insulator 114 sandwich the core 112 from both sides in the axial direction. The coil 115 is wound around the outer peripheral surfaces of the first insulator 113 and the second insulator 114. The inner peripheral surface side of the core 112 faces the outer peripheral surface of the magnet 106 of the rotor 103 via a gap. The core 112, the first insulator 113, the second insulator 114, and the coil 115 form a stator 111.

[0017] In addition, between the cover 102 and the rotor 103 in the axial direction of the shaft 104, a substrate 116 on which electronic components such as resistors and capacitors and a circuit composed of these electronic components are provided is fixed. A sensor 117 is provided on the substrate 116. The sensor 117 is disposed at a position that radially sandwiches a light shielding portion (light shielding piece) 105a provided at the end of the rotor yoke 105. The sensor 117 includes a light source that emits light in the radial direction of the rotor 103 and a light receiving portion that receives light from the light source. That is, the sensor 117 has a cross-sectional shape that is approximately U-shaped when laid down on its side, and one of the inner surfaces 117a and 117b of the two pieces that stand upright in the figure is the light source side, and the other is the light receiving portion side. Either of the inner surfaces 117a and 117b may be the light source side. The light shielding portion 105a can be integrally formed with the rotor yoke 105, which is a magnetic member, making the manufacture easier. The sensor 117 is provided on the substrate 116 between the cover portion 102 and the rotor 103, so that the motor does not become large in size. The substrate 116 is an example of a member. The light shielding portion 105a is an example of a light shielding portion or a convex portion.

[0018] Fig. 3 is a perspective view of peripheral elements of sensor 117 in the first embodiment. In Fig. 3, light-shielding portions 105a extending in the axial direction are provided at equal intervals at the end of rotor yoke 105 on the substrate 116 side, which is fitted to shaft 104. Wiring pins (not shown) are attached to a plurality of holes 116a on substrate 116.

[0019] FIG. 4 is a diagram showing how rotor yoke 105 is attached in the first embodiment. In FIG. 4, rotor yoke 105 is shown in a state before being fixed (fitted) to shaft 104. FIG. 5 is a diagram showing rotor yoke 105 in the first embodiment as seen from another perspective. In the illustrated example, a total of four light shielding portions 105a are provided at the end of rotor yoke 105, but the number of light shielding portions 105a is not limited to this and may be one. Furthermore, when there are multiple light shielding portions 105a, the circumferential lengths of the light shielding portions 105a do not have to be equal, and the circumferential intervals between adjacent light shielding portions 105a do not have to be equal.

[0020] In place of light-shielding portion 105a, a tube (cylinder) made of a transparent material may be provided at the end of rotor yoke 105, and a light-shielding portion made of a light-shielding surface may be provided by coloring this transparent tube or forming a light-shielding film on it, etc. The number of light-shielding portions made of light-shielding surfaces is arbitrary, and the circumferential lengths between the light-shielding portions made of light-shielding surfaces need not be equal, and the circumferential intervals between adjacent light-shielding portions need not be equal.

[0021] With the configuration shown in Figs. 1 to 5, the light shielding portion 105a passes between the light source and the light receiving portion of the sensor 117 as the rotor 103 rotates, intermittently blocking the light, and a signal indicating the rotation state of the rotor 103 is obtained from the sensor 117 and used for speed control, etc. In other words, the signal indicating the rotation state is used in a circuit provided on the substrate 116 and is output to the outside as necessary. In this way, the detection accuracy of the rotation angle can be improved with a simple configuration. In addition, compared to the case of a conventional magnetic sensor using a Hall element, etc., there is an advantage that detection can be performed stably because it is not affected by the temperature of the magnet or the distance between the magnet and the sensor. In addition, compared to the case using a reflecting surface on the magnet and a light emitting element and a light receiving element, there is an advantage that detection can be performed stably because it is not affected by the vibration of the magnet.

[0022] In order to avoid erroneous detection due to dirt or the like adhering to sensor 117, light-shielding portion 105a, or the light-shielding surface, it is desirable to detect the rotation state from a change in the signal from sensor 117 from a state in which light from the light source is blocked to a state in which the light is released. This is because the state in which light from the light source is blocked includes cases in which the light is not actually blocked by light-shielding portion 105a but is blocked by dirt or the like, whereas the state in which the light is released is not affected by dirt or the like.

[0023] Second Embodiment FIG. 6 is an external perspective view of a motor 200 according to a second embodiment, which is an example of an outer rotor type motor in which a rotor is provided on the outside of the motor. In FIG. 6, the motor 200 includes a rotor yoke 204, a substrate 207, and a plate 206. The rotor yoke 204 is cup-shaped and is fixed to a shaft 202 via a hub 203. A circuit is provided on the substrate 207, and a sensor 216 is also provided. The sensor 216 is disposed at a position sandwiching a light-shielding portion (light-shielding piece) 204a provided at an end of the rotor yoke 204. The sensor 216 includes a light source that emits light in a radial direction, and a light-receiving portion that receives light from the light source. The plate 206 is fixed to a sleeve (208) (described later) that rotatably supports the rotor yoke 204.

[0024] Fig. 7 is a vertical cross-sectional view of a motor 200 in the second embodiment. In Fig. 7, a hub 203 is fitted onto a rod-shaped shaft 202, and a cup-shaped rotor yoke 204 made of a magnetic material is fixed to the hub 203. The rotor yoke 204 has a cylindrical portion and a top surface portion (annular flat plate portion) that faces the stator 211 in the axial direction. A ring-shaped magnet 205 is fixed to the inner wall surface (inner surface) of the outer periphery of the rotor yoke 204. The shaft 202, the hub 203, the rotor yoke 204, and the magnet 205 form a rotor 201.

[0025] In addition, shaft 202 is rotatably supported by bearings 209 and 210 fixed (fitted) to the inner surface of sleeve 208 (also referred to as bearing housing). Sleeve 208 is cylindrical, and one end is fixed to plate 206. A small-diameter end of tapered spring 217 is provided on bearing 209 between the axial end of hub 203 and the inner ring of bearing 209. With this configuration, pressure or preload is applied to bearings 209 and 210, and the position of the end of light-shielding portion 204a on the sensor 216 side is stabilized, improving detection accuracy.

[0026] Further, on the outer peripheral surface of the sleeve 208, a core 212, a first insulator 213, a second insulator 214, and a coil 215 are provided. The core 212 is formed by laminating electromagnetic steel sheets. The first insulator 213 and the second insulator 214 sandwich the core 212 from both sides in the axial direction. The coil 215 is wound around the outer peripheral surfaces of the first insulator 213 and the second insulator 214. The outer peripheral surface side of the core 212 faces the inner peripheral surface of the magnet 205 of the rotor 201 via a gap. The core 212, the first insulator 213, the second insulator 214, and the coil 215 form a stator 211.

[0027] In addition, a substrate 207 having a circuit is fixed between the plate 206 and the rotor 201 in the axial direction of the shaft 202. A sensor 216 is provided on the substrate 207. The sensor 216 is disposed at a position that radially sandwiches a light shielding portion (light shielding piece) 204a provided at the end of the rotor yoke 204. The sensor 216 includes a light source that emits light in the radial direction of the rotor 201 and a light receiving portion that receives light from the light source. That is, the sensor 216 has a cross-sectional shape that is approximately U-shaped when laid down on its side, and one of the inner surfaces 216a and 216b of the two pieces that stand upright in the figure is the light source side, and the other is the light receiving portion side. Either of the inner surfaces 216a and 216b may be the light source side. The light shielding portion 204a can be integrally formed with the rotor yoke 204, which is a magnetic member, and this facilitates manufacturing. The sensor 216 is provided on the substrate 207 between the plate 206 and the rotor 201, so that the motor does not become large in size. The substrate 207 is an example of a member. The light shielding portion 204a is an example of a light shielding portion or a convex portion.

[0028] FIG. 8 is a diagram showing how rotor yoke 204 is attached in the second embodiment. In FIG. 8, rotor yoke 204 is shown in a state before being fixed (fitted) to hub 203. Sensor 216 is provided on substrate 207. Shading parts 204a extending in the axial direction are provided at equal intervals at the end of rotor yoke 204 on the substrate 207 side. FIG. 9 is a diagram showing rotor yoke 204 in the second embodiment as seen from another viewpoint. In the illustrated example, a total of four shades 204a are provided at the end of rotor yoke 204, but the number of shades 204a is not limited to this and may be one. In addition, when there are multiple shades 204a, the circumferential lengths of shades 204a do not have to be equal, and the circumferential intervals between adjacent shades 204a do not have to be equal.

[0029] In place of light-shielding portion 204a, a tube (cylinder) made of a transparent material may be provided at the end of rotor yoke 204, and a light-shielding portion made of a light-shielding surface may be provided by coloring this transparent tube, etc. The number of light-shielding portions made of light-shielding surfaces is arbitrary, and the circumferential lengths of the light-shielding portions made of light-shielding surfaces need not be equal, and the circumferential intervals between adjacent light-shielding portions need not be equal.

[0030] With the configuration shown in Figs. 6 to 9, the light shielding portion 204a passes between the light source and the light receiving portion of the sensor 216 as the rotor 201 rotates, intermittently blocking the light, and a signal indicating the rotation state of the rotor 201 is obtained from the sensor 216 and used for speed control, etc. In other words, the signal indicating the rotation state is used in a circuit provided on the substrate 207 and is output to the outside as necessary. In this way, the detection accuracy of the rotation angle can be improved with a simple configuration. In addition, compared to the case of a conventional magnetic sensor using a Hall element or the like, there is an advantage that detection can be performed stably because it is not affected by the temperature of the magnet or the distance between the magnet and the sensor. In addition, compared to the case using a reflecting surface on the magnet and a light emitting element and a light receiving element, there is an advantage that detection can be performed stably because it is not affected by the vibration of the magnet.

[0031] In order to avoid erroneous detection due to dirt or the like adhering to the sensor 216, the light-shielding portion 204a, or the light-shielding surface, it is desirable to detect the rotation state from a change in the signal of the sensor 216 from a state in which the light from the light source is blocked to a state in which the light is released. This is because the state in which the light from the light source is blocked includes cases in which the light is not actually blocked by the light-shielding portion 204a but is blocked by dirt or the like, whereas the state in which the light is released is not affected by dirt or the like.

[0032] (Third embodiment) Fig. 10 is an external perspective view of a rotating device 300 according to a third embodiment, showing an example in which the rotating device 300 is a blower fan. In Fig. 10, the rotating device 300 includes, as parts visible from the outside, a cover 304, an air outlet frame 305, and an impeller 303. That is, the impeller 303 is provided inside the cover 304, and air is blown from inside the air outlet frame 305.

[0033] Fig. 11 is an exploded perspective view of elements of a rotating device 300 according to the third embodiment. In Fig. 11, the rotating device 300 includes a plate 301, a motor 200, an impeller 303, a cover 304, and an air outlet frame 305. That is, the motor 200 is fixed to a hole 301a of a plate-shaped plate 301, and the impeller 303 is fixed to a rotor yoke 204 of the motor 200. The air outlet frame 305 is fixed to the cover 304, and the cover 304 is fixed to the plate 301 by a plurality of screws 302. The motor 200 is an outer type motor shown in Figs. 6 to 9.

[0034] As shown in FIG. 7 etc., the motor 200 has a function of easily detecting the rotation state using the light-shielding portion 204a and the sensor 216, so that the rotation state of the motor 200 in the rotating device 300 can be accurately detected and the air blowing state can be appropriately controlled.

[0035] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0036] As described above, the motor according to the embodiment includes a shaft, a rotor journaled on the shaft, a member facing the rotor in the axial direction of the shaft, and a sensor provided on the member, the sensor having a light source that radiates light in a radial direction and a light receiving unit that receives the light from the light source, and the rotor has a light blocking unit formed at an end in the axial direction, and when the rotor is rotating, the light traveling from the light source to the light receiving unit is blocked by the light blocking unit. This makes it possible to provide a motor that can improve the detection accuracy of the rotation angle.

[0037] In addition, the light blocking portion is a protrusion that protrudes in the axial direction from the end portion of the rotor, thereby improving the detection accuracy of the rotation angle with a simple configuration.

[0038] In addition, the light blocking portion is a light blocking surface formed on a transparent member at the end of the rotor, thereby making it possible to improve the detection accuracy of the rotation angle with a simple configuration.

[0039] Further, a light-shielding portion and a light-collecting portion may be provided in the circumferential direction at the end portion of the rotor yoke 105. In the above-described embodiment, the light-collecting portion corresponds to a gap formed between a plurality of light-shielding portions in the circumferential direction.

[0040] In addition, in the circumferential direction, the light-blocking portion may be longer than the light-collecting portion, or the light-collecting portion may be longer than the light-blocking portion. In addition, in the circumferential direction, the sum of the lengths of the light-collecting portions may be greater than the sum of the lengths of the light-collecting portions, or the sum of the lengths of the light-collecting portions may be greater than the sum of the lengths of the light-blocking portions.

[0041] In addition, the rotor has a cylindrical magnetic member, and the light blocking portion is formed on the magnetic member, whereby the light blocking portion can be formed integrally with the magnetic member of the rotor, facilitating manufacture.

[0042] Furthermore, the rotor yoke is not limited to being made of a magnetic material, but may be made of a non-magnetic material such as a resin material.

[0043] The motor further includes a base and a bearing that rotatably supports the shaft, the shaft being supported by the base via the bearing, and the member being formed between the base and the rotor in the axial direction, thereby preventing the motor from becoming large in size.

[0044] Also, a ring-shaped seat (spring seat) 109 may be fixed (fitted) to the shaft 104 in contact with the inner ring of the bearing 108. A spring 110 may be provided between the seat 109 and the end face of the rotor yoke 105. By providing these configurations as necessary, it is possible to apply a pre-pressure or pre-load to the bearings 107 and 108, thereby stabilizing the position of the end of the light blocking portion 105a on the sensor 117 side and improving the detection accuracy. The spring 110 is an example of an elastic member.

[0045] The rotor may be provided with a base, a bearing that rotatably supports the shaft, and an elastic member that is arranged between the bearing and the rotor or between the bearing and the base and is elastically compressible in the axial direction. This allows an appropriate pressure or preload to be applied to the bearing, and the position of the end of the light blocking part on the sensor side is stabilized, improving detection accuracy.

[0046] In addition, the rotation state is detected from the change in the sensor signal from a state in which the light from the light source is blocked to a state in which the light is released, thereby making it possible to avoid false detections caused by the adhesion of dirt, etc.

[0047] In addition, the present invention is also applicable to motors of the inner rotor type, since the stator surrounds the rotor and the light shielding portion is provided on the outer periphery of the rotor.

[0048] In addition, a stator is provided inside the rotor, and a light-shielding portion is provided on the outer periphery of the rotor, which makes it easy to apply the present invention to an outer rotor type motor.

[0049] Also, instead of the tapered spring provided between the axial end of the hub and the inner ring of the bearing, a cylindrical spring may be provided.

[0050] The rotating device includes the motor and an impeller fixed to the shaft, whereby the rotation state of the motor of the rotating device can be accurately detected and appropriately controlled.

[0051] Furthermore, the present invention is not limited to the above-described embodiment. The present invention also includes configurations in which the above-described components are appropriately combined. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-described embodiment, and various modifications are possible. [Explanation of symbols]

[0052] 100,200 motor, 103,201 rotor, 104,202 shaft, 105,204 rotor yoke, 105a,204a light shielding portion, 106,205 magnet, 107,108,209,210 bearing, 110,217 spring, 111,211 stator, 116,207 board, 117,216 sensor

Claims

1. A shaft, a rotor having a magnetic body having an inner peripheral surface fixed to an outer peripheral surface of the shaft, and a magnet fixed to the outer peripheral surface of the magnetic body; A stator surrounding the rotor; a member facing the rotor in an axial direction of the shaft; A sensor provided on the member; Equipped with The sensor includes: a light source that radiates light in a radial direction; a light receiving portion that receives light from the light source in a radial direction; having The end of the magnetic body includes one or more light-shielding portions protruding in the axial direction, the one or more light-shielding portions are formed of the magnetic material, the one or more light-shielding portions include, in the axial direction, a portion of the outer circumferential surface to which the magnet is fixed, and another portion of the outer circumferential surface; The sensor is disposed at a position on either side of the light blocking portion in a radial direction, When the rotor is rotating, light traveling from the light source to the light receiving unit is blocked by the light blocking unit. Motor.

2. With the base, A bearing that rotatably supports the shaft; Equipped with The shaft is supported by the base via the bearing, The member is formed between the base and the rotor in the axial direction.

2. The motor according to claim 1.

3. With the base, A bearing that rotatably supports the shaft; an elastic member that is arranged between the bearing and the rotor or between the bearing and the base and is elastically compressible in an axial direction; Equipped with 3. The motor according to claim 1 or 2.

4. a rotation state is detected based on a change in the signal from the sensor from a state in which the light from the light source is blocked to a state in which the light is released; The motor according to any one of claims 1 to 3.

5. The motor according to any one of claims 1 to 4, an impeller fixed to the shaft; A rotating device comprising:

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