WO2022244471A1

WO2022244471A1 - Rotary electric machine

Info

Publication number: WO2022244471A1
Application number: PCT/JP2022/014504
Authority: WO
Inventors: 清隆古賀; 裕章柴田; 智矢枡谷
Original assignee: 株式会社アイシン
Priority date: 2021-05-19
Filing date: 2022-03-25
Publication date: 2022-11-24

Abstract

Disclosed is a rotary electric machine comprising a rotor, a non-rotating section rotatably supporting the rotor, a sensor rotor which rotates together with the rotor, and a sensing unit having a coil opposite the sensor rotor in the axial direction. The outer circumferential section of the sensor rotor has a radial protruding section and a radial recessed section at each of predetermined angles, the rotor has a sensor-adjacent section adjacent in the axial direction to the sensor rotor from the opposite side from the sensing unit with respect to the sensor rotor, the sensor-adjacent section has base parts and specific parts having an uneven shape in the axial direction with respect to the base parts, the sensor rotor has magnetic shielding properties in which magnetic flux capable of passing through to the side opposite the sensor-adjacent section in the axial direction is blocked from the side opposite the sensing unit in the axial direction, and the base parts or the specific parts of the sensor-adjacent section are arranged in a periodic manner in the circumferential direction so as to overlap with the recessed sections at each of the predetermined angles or with the recessed sections at each of integral multiples of the predetermined angles in the circumferential direction among the recessed sections at each of the predetermined angles in the sensor rotor when viewed in the axial direction from the coil of the sensing unit.

Description

Rotating electric machine

The present disclosure relates to rotating electric machines.

A rotation detector that uses eddy currents generated in the sensor rotor by the magnetic field generated by the coil of the sensing unit to generate an electric signal in the sensing unit that corresponds to the value of a parameter (e.g., rotation angle) related to the rotation of the rotor. It has been known.

Japanese Unexamined Patent Application Publication No. 2012-231648

In a rotating electric machine, various components are arranged in a limited space inside the case, so there are many cases where metal members other than the sensor rotor are located around the sensing part. Therefore, the detection result of a sensor that uses eddy currents is likely to be affected by such surrounding metal members. In this regard, the rotor, which is one of the peripheral metal members, is likely to affect the detection result of the sensor because the portion adjacent to the sensor rotor in the axial direction extends radially outward.

Therefore, in one aspect, an object of the present disclosure is to reduce the influence of a rotor on the detection result of a sensor that uses eddy currents in a rotating electric machine.

According to one aspect of the present disclosure, a rotor;
a non-rotating portion that rotatably supports the rotor;
a sensor rotor that rotates integrally with the rotor;
a sensing unit having a coil axially facing the sensor rotor;
The sensor rotor has radial protrusions and radial recesses at predetermined angles on an outer peripheral portion,
The rotor has a sensor adjacent portion axially adjacent to the sensor rotor from a side opposite to the sensing portion,
The sensor-adjacent portion includes a base portion and a specific portion that is axially uneven with respect to the base portion,
The sensor rotor has a magnetic shielding property that blocks magnetic flux that can pass from the side facing the sensing portion in the axial direction to the side facing the sensor adjacent portion in the axial direction,
When viewed in the axial direction from the coil of the sensing unit, among the recesses of the sensor rotor at the predetermined angles, the recesses overlap the recesses at the predetermined angle or at integral multiples of the predetermined angle in the circumferential direction. Thus, a rotating electric machine is provided in which the base portion or the specific portion of the sensor adjacent portion is periodically arranged in the circumferential direction.

According to the present disclosure, in a rotating electric machine, it is possible to reduce the influence of the rotor on the detection results of sensors that use eddy currents.

It is a sectional view showing roughly a section structure of a motor by a present Example. 1B is an enlarged view of the Q1 portion of FIG. 1A; FIG. FIG. 4 is a perspective view showing a sensor rotor and a sensing section in the rotation sensor according to the embodiment; It is a figure which shows the relationship between the sensing part of a rotation sensor by a present Example, and a sensor rotor. FIG. 4 is a diagram showing a portion of the sensor rotor according to the present embodiment, which is axially opposed to the sensing section, viewed in the axial direction; FIG. 4 is a schematic diagram illustrating waveforms of sensor outputs generated by the sensing unit according to the embodiment; FIG. 2 is an explanatory diagram conceptually explaining the features of the configuration of the present embodiment, and is a perspective view of a sensor rotor and a part of its periphery (a part of the rotor) viewed from the X1 side. FIG. 7 is a perspective view of FIG. 6 with the sensor rotor removed; FIG. 7 is a plan view of FIG. 6 with the sensor rotor removed; FIG. 7 is a plan view of FIG. 6 viewed in the axial direction, showing only a half above the rotation axis; FIG. 10 is an explanatory diagram of the influence of the sensor adjacent portion of the rotor on the sensor output; FIG. 4 is a waveform of a sensor output generated by a sensing section, showing a waveform of a sensor output affected by a sensor adjacent section; FIG. 6 is an axial plan view schematically showing a sensor adjacent portion and a sensor rotor according to a comparative example; FIG. 10 is a waveform of a sensor output generated by a sensing unit, showing a waveform of a sensor output affected by a sensor adjacent portion according to a comparative example; It is explanatory drawing of the further effect of a present Example. FIG. 11 is an axial plan view schematically showing a sensor adjacent portion and a sensor rotor in the motor according to Example 2; FIG. 11 is an axial plan view schematically showing a sensor adjacent portion and a sensor rotor in a motor according to Example 3; FIG. 11 is a perspective view of a sensor rotor according to Example 3; FIG. 10 is a waveform of the sensor output generated by the sensing unit in Example 3, and shows the waveform of the sensor output affected by the sensor adjacent portion.

Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples, and the present invention is not limited to these, and shapes and the like in the drawings may be partially exaggerated for convenience of explanation.

[Example 1]
FIG. 1A is a cross-sectional view schematically showing the cross-sectional structure of the motor 1 according to this embodiment. FIG. 1B is an enlarged view of the Q1 portion of FIG. 1A.

The rotating shaft 12 of the motor 1 is illustrated in FIG. 1A. In the following description, the axial direction refers to the direction in which the rotation shaft (rotation center) 12 of the motor 1 extends, and the radial direction refers to the radial direction around the rotation shaft 12 . Therefore, the radially outer side refers to the side away from the rotating shaft 12 , and the radially inner side refers to the side toward the rotating shaft 12 . Also, the circumferential direction corresponds to the direction of rotation about the rotating shaft 12 .

Also, in FIG. 1A, the X1 side and the X2 side along the X direction parallel to the direction of the rotating shaft 12 (that is, the axial direction) are defined. In the following description, the terms X1 side and X2 side may be used to express relative positional relationships.

The motor 1 may be a vehicle drive motor used in, for example, a hybrid vehicle or an electric vehicle. However, the motor 1 may be used for any other purpose.

The motor 1 is of the inner rotor type, and the stator 21 is provided so as to surround the radially outer side of the rotor 30 . The radially outer side of the stator 21 is fixed to the motor housing 10 . The stator 21 includes a stator core 211 made of, for example, an annular laminated magnetic steel plate, and a plurality of slots (not shown) around which the coils 22 are wound are formed radially inside the stator core 211 .

The rotor 30 is arranged radially inside the stator 21 . The rotor 30 has a rotor core 32 and a rotor shaft 34 . The rotor core 32 is fixed to the radially outer surface of the rotor shaft 34 and rotates together with the rotor shaft 34 . Rotor core 32 may be secured to rotor shaft 34 by shrink fitting or the like. The rotor shaft 34 is rotatably supported by the motor housing 10 via

bearings

14a and 14b. It should be noted that the rotor shaft 34 defines the rotating shaft 12 of the motor 1 .

The rotor core 32 is made of, for example, an annular magnetic layered steel plate. Permanent magnets 321 are embedded in the magnet holes 324 of the rotor core 32 . Alternatively, a permanent magnet such as permanent magnet 321 may be embedded in the outer peripheral surface of rotor core 32 . Note that the arrangement of the permanent magnets 321 and the like are arbitrary.

End plates

35A and 35B are attached to both sides of the rotor core 32 in the axial direction.

End plates

35A and 35B cover axial end faces of rotor core 32 . The

end plates

35A and 35B have a detachment prevention function to prevent the permanent magnets 321 from detaching from the rotor core 32, as well as a function to adjust the imbalance of the rotor 30 (a function to eliminate the imbalance by cutting or the like). good.

The

end plates

35A, 35B are made of a non-magnetic material. The

end plates

35A, 35B are preferably made of aluminum. In this case, cutting becomes easier, and the function of adjusting the imbalance of the rotor 30 by the

end plates

35A, 35B can be effectively realized. However, in a modified example, the

end plates

35A and 35B may be made of stainless steel or the like.

The rotor shaft 34 has a hollow portion 34A as shown in FIG. 1A. The hollow portion 34A extends over the entire length of the rotor shaft 34 in the axial direction. The hollow portion 34A may be axially open on both sides in the axial direction. The hollow portion 34A may function as an oil passage 801 through which cooling oil passes.

In this embodiment, the magnetic pole configuration of the rotor core 32 is arbitrary. For example, the number of magnetic poles may be 8 or other than 8, and instead of or in addition to the permanent magnet 321, the pair of permanent magnets forming each magnetic pole may be arranged so that the distance in the circumferential direction increases toward the outer side in the radial direction. It may be arranged in a spreading manner. Also, the rotor core 32 may be formed with a flux barrier, an oil passage, and the like.

Also, although the rotor shaft 34 has a hollow portion 34A in this embodiment, it may be solid. Alternatively, the rotor shaft 34 may be formed by joining two or more parts. Also, the motor 1 may be cooled by cooling water (for example, lifelong coolant) instead of or in addition to oil. Further, although the motor 1 is of the inner rotor type in this embodiment, it may be of the outer rotor type.

In this embodiment, the motor 1 has a rotation sensor 80 that detects parameter values relating to the rotation of the rotor 30 . The parameters related to the rotation of the rotor 30 are arbitrary, and may be, for example, the presence or absence of rotation of the rotor 30, the rotation angle of the rotor 30 from a predetermined reference angle, the rotation speed, the magnetic pole position, and the like. As an example, the rotation sensor 80 detects the rotation angle of the rotor 30 below.

The rotation sensor 80 is provided on one end side of the rotor shaft 34 . In this embodiment, the rotation sensor 80 is provided at the X1 side end of the rotor shaft 34 as shown in FIG. 1A, but may be provided at the X2 side end.

FIG. 2 is a perspective view showing the sensor rotor 81 and the sensing section 82 of the rotation sensor 80 as viewed from the X1 side. It should be noted that illustration of the sensor support portion 84 is omitted in FIG. 2 (as well as FIG. 3 described later).

The rotation sensor 80 includes a sensor rotor 81 , a sensing section 82 and a sensor support section 84 .

The sensor rotor 81 is made of a conductor, for example, and rotates integrally with the rotor 30 . The sensor rotor 81 has an annular shape with a circular central hole 811 centered on the rotating shaft 12 . The sensor rotor 81 may be attached so as to rotate together with the rotor shaft 34 by passing the rotor shaft 34 through the center hole 811 thereof. For example, the sensor rotor 81 has a radial concave portion or convex portion formed in the rotor shaft 34 , and a diameter that fits into the radial concave portion or convex portion of the rotor shaft 34 on the inner peripheral edge of the center hole 811 of the sensor rotor 81 . Directional protrusions or recesses may be formed.

The sensor rotor 81 has an outer diameter that changes periodically. As a result, the outer diameter of the sensor rotor 81 at the circumferential position facing the sensing portion 82 in the axial direction changes periodically each time the rotation angle of the rotor 30 changes by a predetermined angle. The predetermined angle may be appropriately determined according to the number of magnetic poles and the like at the time of design. In this embodiment, the sensor rotor 81 has eight radial protrusions and recesses alternately per turn. In this case, the outer diameter of the sensor rotor 81 at the circumferential position facing the sensing portion 82 in the axial direction changes periodically every time the rotation angle of the rotor 30 changes by 45 degrees.

The sensor rotor 81 is preferably permeable from the side (X1 side) facing the sensing section 82 in the axial direction to the side (X2 side) facing the rotor core 32 (or the sensor adjacent section 300 described later) in the axial direction. It has a magnetic shielding property that blocks magnetic flux. For example, the sensor rotor 81 may achieve such a magnetic shielding property by having a relatively large thickness, or by having a layer of shielding material on the surface on the X2 side.

Note that, in a modified example, the sensor rotor 81 may have a periodically changing thickness (axial thickness) instead of or in addition to the periodically changing outer diameter. In this case, the thickness of the sensor rotor 81 at the circumferential position facing the sensing portion 82 in the axial direction changes periodically every time the rotation angle of the rotor 30 changes by a predetermined angle.

The sensing part 82 is in the form of a substrate 820 and is arranged so as to face the sensor rotor 81 in the axial direction and be close to it. As shown in FIG. 2, the substrate 820 may have an arcuate shape when viewed in the axial direction, and may extend only along a partial circumferential section of the entire circumference. Moreover, the substrate 820 may extend not only in an arc shape but also in the entire circumference. The sensing portion 82 is supported by a non-rotating portion (motor housing 10 in this embodiment) of the motor 1 by a sensor support portion 84 (see FIG. 1B).

The sensing section 82 detects the rotation angle of the rotor 30 using eddy currents. 3 to 5 are explanatory diagrams of the principle of detection by the sensing section 82. FIG. 3 shows the relationship between the sensing portion 82 of the rotation sensor 80 and the sensor rotor 81, and FIG. 4 shows a portion of the sensor rotor 81 axially facing the sensing portion 82 as viewed in the axial direction. It is a diagram. FIG. 5 is a schematic diagram illustrating the waveform of the sensor output (electrical signal) generated by the sensing section 82. As shown in FIG. In FIG. 5, the horizontal axis represents the rotation angle of the rotor 30 and the vertical axis represents the magnitude of the sensor output, and the time-series waveform of the sensor output (electrical signal) generated by the sensing unit 82 is schematically shown. there is Note that FIG. 5 schematically shows time-series waveforms for a predetermined angle (45 degrees in this embodiment) in the rotation angle of the rotor 30 .

The sensing section 82 may be in the form of a substrate 820 on which a sensor coil 821 and a processing circuit section 822 are mounted, as shown in FIG. Some or all of the functions of the processing circuit section 822 may be realized by an external control device (not shown).

The sensor coils 821 may be formed on both surfaces of the substrate 820 as shown in FIG. 3, for example. Note that, in a modification, the sensor coils 821 may be formed in the inner layer of the substrate 820 instead of or in addition to the surfaces on both sides of the substrate 820 . The sensor coil 821 may be formed by printed conductors, for example. The sensor coil 821 is wound around a central axis O parallel to the X direction.

The processing circuit unit 822 causes the sensor rotor 81 to generate an eddy current by energizing the sensor coil 821 . Specifically, as schematically shown in FIG. 3, when the sensor coil 821 is energized, a magnetic flux B1 passing through the sensor coil 821 is generated. When the magnetic flux B1 penetrating the sensor coil 821 contacts the surface of the sensor rotor 81 facing the sensor coil 821 in the axial direction, an eddy current is generated on the surface of the sensor rotor 81 . In FIG. 4, the manner in which eddy currents are generated is schematically indicated by an arrow Ie. Although FIG. 4 schematically shows eddy currents in specific directions, the direction of the eddy currents is determined according to the direction of the current flowing through the sensor coil 821 . The eddy currents are oriented to generate a magnetic flux that reduces the magnetic flux B1. Therefore, due to the eddy currents, a magnetic flux B2 (not shown) is generated which reduces the magnetic flux B1. The magnitude of the magnetic flux B2 is proportional to the magnitude of the eddy current. The magnitude of the eddy current increases as the surface area of the portion of the sensor rotor 81 facing the sensor coil 821 in the axial direction increases. In this embodiment, as described above, the sensor rotor 81 has an outer diameter that changes periodically. Then it changes. More specifically, the surface area of the portion of the sensor rotor 81 axially facing the sensor coil 821 changes sinusoidally as the rotation angle of the rotor 30 changes. Therefore, in the present embodiment, the time-series waveform of the sensor output (electrical signal) generated by the sensing unit 82 has one cycle of Draw a sine wave. Therefore, the rotation angle of the rotor 30 can be detected based on such sensor output (electrical signal).

The sensor support portion 84 is fixed to the non-rotating portion (motor housing 10 in this embodiment) of the motor 1 (schematically shown in FIGS. 1A and 1B) and supports the sensing portion 82 . The sensor support portion 84 may support the sensing portion 82 by any means such as adhesives, fasteners, or fitting. In this embodiment, as an example, the sensor support section 84 supports the sensing section 82 via a potting resin section 86 for sealing, for example. In this case, the potting resin portion 86 is joined to the sensing portion 82 and the sensor support portion 84 to integrate the sensing portion 82 and the sensor support portion 84 . In this case, the number of parts can be reduced compared to the case where the sensing section 82 and the sensor support section 84 are separate parts. In addition, since the sensing portion 82 is assembled by assembling the sensor support portion 84 to the motor housing 10, the assembly is easier than when the sensing portion 82 and the sensor support portion 84 are separate components. is. The potting resin portion 86 may be filled from the opening of the sensor support portion 84 on the X2 side.

The sensor support portion 84 preferably supports the sensing portion 82 so that the sensing portion 82 is axially close to the sensor rotor 81 . In this case, the sensor support portion 84 is such that the axial positional relationship between the sensor rotor 81 and the sensing portion 82 is such that the axial gap between the sensor rotor 81 and the sensing portion 82 is between the movable portion and the fixed portion. A positional relationship may be achieved that corresponds to the minimum clearance required between.

Here, the features of the configuration of this embodiment will be conceptually described with reference to FIGS. 6 to 11. FIG.

6 to 9 are explanatory diagrams for conceptually explaining the features of the configuration of this embodiment. FIG. 6 shows the sensor rotor 81 and a portion of its periphery (a portion of the rotor 30) viewed from the X1 side. 7 is a perspective view with the sensor rotor 81 removed from FIG. 6, and FIG. 8 is a plan view (plan view viewed in the axial direction) with the sensor rotor 81 removed from FIG. . 9 is a plan view of FIG. 6 viewed in the axial direction, showing only the upper half of the rotating shaft 12. As shown in FIG. 6 to 9 are conceptual diagrams, and in particular the configuration of the rotor 30 is shown very schematically. FIG. 10 is an explanatory diagram of the influence of the sensor adjacent portion 300 of the rotor 30 on the sensor output, and is a diagram schematically showing the flow of magnetic flux. Note that the flow of magnetic flux shown in FIG. 10 is schematically shown in a state before being affected by the sensor adjacent portion 300 and the sensor rotor 81 . FIG. 11 is a diagram showing the waveform of the sensor output (electrical signal) generated by the sensing section 82 in this embodiment, and showing the waveform of the sensor output affected by the sensor adjacent section 300. As shown in FIG. In FIG. 11, the horizontal axis represents the rotation angle of the rotor 30 and the vertical axis represents the magnitude of the sensor output, and the time-series waveform of the sensor output (electrical signal) generated by the sensing unit 82 is schematically shown. there is In FIG. 11 (the same applies to FIGS. 12B and 17 described later), time-series waveforms for twice (for two cycles) a predetermined angle (45 degrees in this embodiment) in the rotation angle of the rotor 30 are shown schematically. are shown.

The rotor 30 has a sensor adjacent portion 300 axially adjacent to the sensor rotor 81 from the side opposite to the sensing portion 82 (the X2 side in this embodiment). The sensor adjacent portion 300 may be realized by any one or more components of the rotor 30 (components that rotate together with the rotor shaft 34), for example, in the example shown in FIG. It may be the X1 side end of the rotor core 32, the end plate 35A, the washer 39, or the like. The washer 39 is provided between the flange portion 346 (a portion of the rotor shaft 34 on the X1 side) and the rotor core 32 in the axial direction. 32) may have the function of reducing the stress that may occur in the rotor core 32 due to the axial force applied to the rotor core 32).

By the way, the sensor adjoining portion 300 is arranged on the opposite side of the sensor rotor 81 from the sensing portion 82 (the X2 side in this embodiment), but is arranged near the sensor rotor 81 and has a larger diameter than the sensor rotor 81. Since it extends in the outward direction, it may affect the magnetic flux B1 passing through the sensor coil 821 (see magnetic flux B1-1 in FIG. 10). That is, there is a possibility that an eddy current is generated in the sensor adjacent portion 300 due to the magnetic flux B1 penetrating the sensor coil 821 . Such eddy currents, like the eddy currents in the sensor rotor 81, generate a magnetic flux B3 (not shown) in a direction that reduces the magnetic flux B1.

In this regard, in this embodiment, the sensor adjacent portion 300 is such that the magnitude of the eddy current generated by the magnetic flux B1 in the sensor adjacent portion 300 changes every time the rotation angle of the rotor 30 changes by a predetermined angle (45 degrees in this embodiment). is configured to periodically change to

Specifically, as shown in FIGS. 6 to 9, the sensor adjacent portion 300 includes a first portion 301 having a constant outer diameter and a second portion 302 having a significantly larger outer diameter than the first portion 301. It has periodically along the circumferential direction. That is, the sensor adjacent portion 300 has the same phase and period as the sensor rotor 81 and has an outer diameter that changes periodically. In other words, the sensor rotor 81 has a small diameter portion 810 at a circumferential position corresponding to the first portion 301 , and a large diameter portion 812 at a circumferential position corresponding to the second portion 302 . have. In this case, the outer diameter of the large diameter portion 812 is significantly smaller than the outer diameter of the second portion 302 (see FIG. 9). In this way, in this embodiment, the outer diameter of the sensor adjacent portion 300 at the circumferential position facing the sensing portion 82 in the axial direction changes the rotation angle of the rotor 30 by a predetermined angle (45 degrees in this embodiment). It changes periodically each time. In this specification, "the outer diameter of one of the two parts is significantly larger or smaller than that of the other" means that when one part faces the sensor coil 821 in the axial direction and when the other part faces the sensor coil 821 It refers to a mode that produces a significant difference in sensor output (for example, a difference that exceeds the minimum resolution of the sensor output) between when it is axially opposed to .

By the way, the magnitude of the eddy current in the sensor adjacent portion 300 increases as the surface area of the portion of the sensor adjacent portion 300 that directly faces the sensor coil 821 in the axial direction increases, as in the case of the sensor rotor 81 described above. . The expression that the sensor adjacent portion 300 directly faces the sensor coil 821 in the axial direction indicates a positional relationship in which the magnetic flux B1 from the sensor coil 821 can reach without being blocked by the sensor rotor 81 . In this embodiment, as described above, the sensor adjacent portion 300 has an outer diameter that changes periodically. It changes when the rotation angle changes. More specifically, the surface area of the portion of the sensor adjacent portion 300 that axially faces the sensor coil 821 is changed by one cycle of a sine wave, rectangular wave, triangular wave, Or it changes in a change mode corresponding to the class.

Therefore, in this embodiment, the eddy current generated in the sensor-adjacent portion 300 due to the magnetic flux B1 draws one cycle of a sine wave, a square wave, or a triangular wave every time the rotation angle of the rotor 30 changes by 45 degrees. cyclically change in mode. Therefore, the magnetic flux B3 generated due to the eddy currents generated in the sensor adjacent portion 300 also has one cycle of a sine wave, rectangular wave, triangular wave, or the like every time the rotation angle of the rotor 30 changes by 45 degrees. changes periodically in the manner of drawing

Further, in this embodiment, the sensor rotor 81 has a portion ( It has a small diameter portion 810 and a large diameter portion 812). As a result, in this embodiment, the time-series waveform of the sensor output (electrical signal) generated by the sensing section 82 is different from the basic waveform caused by the small-diameter portion 810 and the large-diameter portion 812 of the sensor rotor 81. The waveform has a substantially constant offset due to the portion 300 (the portion extending radially outward from the sensor rotor 81 when viewed in the axial direction). Specifically, in this embodiment, as shown in FIG. 11, the time-series waveform of the sensor output (electrical signal) generated by the sensing unit 82 is different from the ideal waveform 500 shown in FIG. The waveform 501 is offset by a constant offset amount (see Δ1 in FIG. 11) corresponding to the magnetic flux B3. In this embodiment, as described above, the magnetic flux B3 changes periodically each time the rotation angle of the rotor 30 changes by a predetermined angle (45 degrees in this embodiment). Every time the angle changes by 45 degrees, it changes periodically (in FIG. 11, it changes periodically in a manner that draws a sine wave). Therefore, the rotation angle of the rotor 30 can be accurately detected based on such sensor output (electrical signal).

In addition, in the examples shown in FIGS. 6 to 9, the second portion 302 is a radial protrusion with respect to the first portion 301, and the first portion 301 is a radial recess with respect to the second portion 302. In this case, one of the first part 301 and the second part 302 is an example of the "base part" in the claims, and the other is an example of the "specific part" in the claims. be. In addition, in the examples shown in FIGS. 6 to 9, the second portion 302 is a radial projection with respect to the first portion 301, and the first portion 301 is a radial recess with respect to the second portion 302. , alternatively or additionally, may be axial unevenness. For example, the first portion 301 is a flat portion that does not have unevenness in the axial direction as a base, and the second portion 302 is a portion that is uneven in the axial direction with respect to the flat portion. be. This also applies to the second and third embodiments, which will be described later.

When the sensor adjacent portion 300 includes the end plate 35A, the protrusions and recesses related to the sensor adjacent portion 300 include oil grooves (including forms such as oil holes and oil passages) formed in the end plate 35A. ) or a balance adjustment hole (a hole for adjusting the imbalance of the rotor 30). Moreover, in the case of a configuration in which the end plate 35A is not provided, the sensor adjacent portion 300 may include the end portion of the rotor core 32 on the X1 side. In this case, the protrusions and recesses may be realized by an oil groove, a flux barrier, a crimped portion, or the like that may be formed at the X1-side end of the rotor core 32 . In this case, the crimping portion may be a crimping portion for fixing the rotor shaft 34 to the rotor shaft 34 . Further, when the sensor adjacent portion 300 includes the rotor shaft 34 (motor hub), the protrusions and recesses may be realized by oil grooves, welded portions, or the like that may be formed in the rotor shaft 34 .

Here, the effects of this embodiment will be described in comparison with the comparative example with reference to FIGS. 12A and 12B. FIG. 12A is an axial plan view schematically showing a sensor adjacent portion 300 ′ and a sensor rotor 81 according to a comparative example, showing only the upper half of the rotating shaft 12 as in FIG. 9 . FIG. 12B is a waveform of the sensor output (electrical signal) generated by the sensing unit 82 in the comparative example, showing the waveform of the sensor output influenced by the sensor adjacent portion 300' according to the comparative example. In FIG. 12B, the horizontal axis represents the rotation angle of the rotor 30, and the vertical axis represents the sensor output magnitude. there is

As schematically shown in FIG. 12A, the sensor adjacent portion 300' according to the comparative example includes a first portion 301' having a constant outer diameter and a second portion 302' having a significantly larger outer diameter than the first portion 301'. and irregularly along the circumferential direction. For example, the second portion 302'-1 has a wider circumferential extension range than the second portion 302'-2 and continuously extends over an angle of 45 degrees or more. In such an irregular configuration, as shown in FIG. 12B, the time-series waveform of the sensor output (electrical signal) generated by the sensing section 82 becomes irregular. That is, in the comparative example, the sensor output does not have the regularity of drawing a sine wave of one cycle each time the rotation angle of the rotor 30 changes by 45 degrees. In the example shown in FIG. 12B, in the angular range A1 for one cycle, the center value of the sensor output is the ideal median value indicated by the dotted line 1300 in FIG. 12B (for example, the ideal waveform 500 shown in FIG. The central value of the sensor output is offset upward (see arrow R1301) with respect to the central value of the amplitude), while the central value of the sensor output is lower than the ideal central value in the angle range A2 for one subsequent cycle. (see arrow R1302), the amount of offset is not constant. In such a case, the rotation angle of the rotor 30 cannot be accurately detected based on such sensor output (electrical signal). For example, it is difficult to correct the offset of the sensor output, and the reliability of the sensor information from the rotation sensor 80 may decrease.

On the other hand, according to the present embodiment, as described above, it is possible to obtain the sensor output of the waveform 501 (see FIG. 11) offset by a constant offset amount corresponding to the magnetic flux B3. Therefore, according to this embodiment, it is possible to effectively reduce the possibility that the reliability of the sensor information from the rotation sensor 80 is lowered due to the sensor adjacent portion 300 .

In this embodiment, as described above, in the sensor adjacent portion 300, the magnitude of the eddy current generated by the magnetic flux B1 in the sensor adjacent portion 300 is such that the rotation angle of the rotor 30 is a predetermined angle (45 degrees in this embodiment). ) is configured to change periodically each time it changes, but is not limited to this. For example, in the modified example, the sensor adjacent portion 300 is configured so that the magnitude of the eddy current generated by the magnetic flux B1 in the sensor adjacent portion 300 changes every time the rotation angle of the rotor 30 changes by an integral multiple of a predetermined angle (for example, 90 degrees). may be configured to change periodically to . In this case, although the offset amount (see Δ1 in FIG. 11) is not constant, it changes periodically with a period that is an integral multiple of two or more times the change period of the outer diameter of the sensor rotor 81 (the period corresponding to the predetermined angle). . Therefore, also in this case, it is possible to obtain a sensor output capable of detecting the rotation angle of the rotor 30 with higher accuracy than in the comparative example.

FIG. 13 is an explanatory diagram of further effects of this embodiment, and is a plan view showing the same portion as in FIG. FIG. 13 shows a projection area R130 of the sensor coil 821 of the sensing unit 82 and a trajectory area R131 (a trajectory area viewed in the axial direction) when the projection area R13 is rotated 360 degrees around the rotation axis 12. there is In this case, the portion of the sensor adjacent portion 300 that overlaps the trajectory region R131 when viewed in the axial direction substantially affects the sensor information from the rotation sensor 80 . Therefore, according to the present embodiment, it is possible to increase the degree of design freedom in the area of the sensor adjacent portion 300 other than the portion overlapping the trajectory area R131 when viewed in the axial direction.

[Example 2]
In the following description of the second embodiment, constituent elements that may be the same as those of the first embodiment described above may be given the same reference numerals, and the description thereof may be omitted.

FIG. 14 is an axial plan view schematically showing the sensor adjacent portion 300 and the sensor rotor 81A in the motor 1A according to the second embodiment. be.

A motor 1A according to the second embodiment differs from the motor 1 according to the first embodiment described above in that the sensor rotor 81 is replaced with a sensor rotor 81A.

In the first embodiment described above, the magnitude of the eddy current generated in the sensor adjacent portion 300 due to the magnetic flux B1 from the sensing portion 82 is defined as the magnitude of the eddy current generated in the sensor rotor 81 due to the magnetic flux B1 from the sensing portion 82. Along with the size, it is periodically changed each time the rotation angle of the rotor 30 changes by a predetermined angle.

On the other hand, in the present embodiment, the magnitude of the eddy current that may occur in the sensor adjacent portion 300 due to the magnetic flux B1 from the sensing portion 82 is controlled by the structure of the sensor rotor 81A regardless of the rotation angle of the rotor 30. A similar effect can be obtained by maintaining a substantially constant value.

Specifically, in this embodiment, the sensor rotor 81A is arranged so as to overlap the first portion 301 and the second portion 302 of the sensor adjacent portion 300 when viewed in the axial direction, as shown in FIG. The sensor rotor 81A has a small diameter portion 810A at a circumferential position corresponding to the first portion 301, and a large diameter portion 812A at a circumferential position corresponding to the second portion 302. The outer diameter of the portion 810A may be equal to or greater than the outer diameter of the first portion 301, and the outer diameter of the large diameter portion 812A may be equal to or greater than the outer diameter of the second portion 302. Note that a portion 304 radially outward of the second portion 302 in the sensor adjacent portion 300 is a portion that does not have unevenness or holes, and an eddy current that may be caused by the magnetic flux B1 from the sensing portion 82 is substantially reduced. This is a constant part.

In this case, since the first portion 301 and the second portion 302 of the sensor adjacent portion 300 do not directly face the sensor coil 821 in the axial direction, the magnetic flux B1 from the sensing portion 82 causes the sensor adjacent portion 300 to The magnitude of the eddy current generated in the sensor-adjacent portion 300 has a substantially constant value due to the portion 304 (the portion having no irregularities, holes, etc.) radially outside the second portion 302 . As a result, the magnitude of the eddy current that may occur in the sensor adjacent portion 300 due to the magnetic flux B1 from the sensing portion 82 can be maintained at a substantially constant value regardless of the rotation angle of the rotor 30. FIG. It should be noted that the substantially constant value is a concept that includes a mode in which the amount of variation is within about 10%.

Also in this embodiment, the sensor rotor 81A has a portion ( It has a small diameter portion 810A and a large diameter portion 812B). As a result, in this embodiment, the time-series waveform of the sensor output (electrical signal) generated by the sensing section 82 is the second The waveform has a substantially constant amount of offset due to a portion 304 (a portion having no irregularities or holes) located radially outside the portion 302 . Specifically, in this embodiment, the time-series waveform of the sensor output (electrical signal) generated by the sensing section 82 is similar to the waveform 501 shown in FIG. Therefore, the rotation angle of the rotor 30 can be accurately detected based on such sensor output (electrical signal).

Note that the sensor rotor 81A according to this embodiment covers the second portion 302, which has a larger outer diameter than the first portion 301, in the axial direction. It extends radially outward beyond the sensor rotor 81 that is not axially covered. That is, the small-diameter portion 810A and the large-diameter portion 812A of the sensor rotor 81A according to this embodiment have larger outer diameters than the small-diameter portion 810 and the large-diameter portion 812 of the sensor rotor 81 according to the first embodiment, respectively. Correspondingly, in this embodiment, the sensing unit 82 may be arranged radially outside the mounting position (see FIGS. 1A and 1B) of the first embodiment described above.

In addition, since the sensor rotor 81A according to this embodiment covers the second portion 302 in the axial direction, the sensor output of the sensing portion 82 is not substantially affected by the second portion 302. Therefore, the sensor rotor 81A according to this embodiment may be applied to a sensor adjacent portion that does not periodically have the second portion 302 instead of the sensor adjacent portion 300. FIG. That is, in the case of this embodiment, one or more second portions 302 in the sensor adjacent portion 300 may be arranged at a radial position corresponding to one of the large diameter portions 812A of the sensor rotor 81A. It is not necessary to arrange the second part 302 in a one-to-one correspondence with each of the large diameter portions 812A. For example, the sensor adjacent portion may have seven second portions 302 instead of eight, in which case each of the seven second portions 302 corresponds to the large diameter portion 812A of the sensor rotor 81A. may be arranged at one radial position where Also, at least one of the one or more second parts 302 may have a shape different from the others, increasing the degree of freedom in shape. For example, each of the one or more second portions 302 may have a different axial relief configuration than the others.

[Example 3]
In the following description of the third embodiment, constituent elements that may be the same as those of the first embodiment described above may be given the same reference numerals, and description thereof may be omitted.

FIG. 15 is an axial plan view schematically showing the sensor adjacent portion 300 and the sensor rotor 81B in the motor 1B according to the third embodiment, showing only the upper half of the rotating shaft 12 as in FIG. be. FIG. 16 is a perspective view of the sensor rotor 81B according to this embodiment, and FIG. 17 shows the waveform of the sensor output (electrical signal) generated by the sensing section 82 in this embodiment, which is affected by the sensor adjacent section 300. FIG. 10 is a diagram showing waveforms of sensor outputs subjected to . In FIG. 17, the horizontal axis represents the rotation angle of the rotor 30 and the vertical axis represents the magnitude of the sensor output, and the time-series waveform of the sensor output (electrical signal) generated by the sensing unit 82 is schematically shown. there is

The motor 1B according to the third embodiment differs from the motor 1 according to the first embodiment described above in that the sensor rotor 81 is replaced with a sensor rotor 81B.

On the other hand, in the present embodiment, the magnitude of the eddy current that can be generated in the sensor adjacent portion 300 due to the magnetic flux B1 from the sensing portion 82 is controlled by the structure of the sensor rotor 81B regardless of the rotation angle of the rotor 30. A similar effect can be obtained by maintaining a substantially constant value.

Specifically, in this embodiment, the sensor rotor 81B has a cover portion 813B on the radially outer side of each of the small diameter portion 810 and the large diameter portion 812, as shown in FIGS. The cover portion 813B may be formed thinner than each of the small diameter portion 810 and the large diameter portion 812 . The cover portion 813B is made of the same material as the small-diameter portion 810 and the large-diameter portion 812, but in a modification, it may be made of a material different from that of the small-diameter portion 810 and the large-diameter portion 812 (for example, a high magnetic permeability material). good. The cover portion 813B is continuous from the radially outer edge portions of the small diameter portion 810 and the large diameter portion 812, and extends radially across the entire sensor rotor 81B so as to have a constant outer diameter. In this case, the outer diameter of the sensor rotor 81B is determined by the radial outer edge of the cover portion 813B. The cover portion 813B extends radially so as to overlap the second portion 302 of the sensor adjacent portion 300 (not visible due to the cover portion 813B in FIG. 15) when viewed in the axial direction. The outer diameter of the sensor rotor 81B may be greater than or equal to the outer diameter of the second portion 302 (see FIG. 8) of the sensor adjacent portion 300. As shown in FIG.

In this case, since the first portion 301 and the second portion 302 of the sensor adjacent portion 300 do not directly face the sensor coil 821 in the axial direction, the magnetic flux B1 from the sensing portion 82 causes the sensor adjacent portion 300 to The magnitude of the eddy current that can occur in the sensor adjoining portion 300 has a substantially constant value due to the portion 304 (the portion having no irregularities or holes) radially outside the cover portion 813B. As a result, the magnitude of the eddy current that may occur in the sensor adjacent portion 300 due to the magnetic flux B1 from the sensing portion 82 can be maintained at a substantially constant value regardless of the rotation angle of the rotor 30. FIG.

Also in this embodiment, the sensor rotor 81B has a portion ( It has a small diameter portion 810 and a large diameter portion 812). In this embodiment, the cover portion 813B of the sensor rotor 81B directly faces the sensor coil 821 in the axial direction. The magnitude of the current becomes a substantially constant value. This is because the outer diameter of the cover portion 813B is constant as described above. As a result, in this embodiment, the time-series waveform of the sensor output (electrical signal) generated by the sensing unit 82 is different from the waveform caused by the small diameter portion 810 and the large diameter portion 812 in the cover portion 813B and the portion 304. The resulting waveform has a substantially constant amount of offset. Specifically, in this embodiment, as shown in FIG. 17, a waveform 502 having a substantially constant offset amount (see Δ2 in FIG. 17) with respect to the ideal waveform 500 shown in FIG. 5 is obtained. Therefore, the rotation angle of the rotor 30 can be accurately detected based on such sensor output (electrical signal).

Since the sensor rotor 81B according to this embodiment covers the second portion 302 in the axial direction with the cover portion 813B, the sensor output of the sensing portion 82 is not substantially affected by the second portion 302. . Therefore, instead of the sensor-adjacent portion 300, it may be applied to the sensor-adjacent portion that does not have the second portion 302 periodically. In particular, in the case of this embodiment, since the cover portion 813B is formed over the entire circumference, the second portion 302 may be formed at any position in the circumferential direction. Therefore, according to this embodiment, the degree of freedom in designing the sensor adjoining portion 300 can be effectively increased.

Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope described in the claims. It is also possible to combine all or more of the constituent elements of the above-described embodiments. Further, among the effects of each embodiment, the effects related to dependent claims are additional effects distinguished from generic concepts (independent claims).

For example, in the first embodiment described above (the same applies to the second and third embodiments), the sensor rotor 81 has an outer diameter that changes periodically along the cycle. Instead of or in addition to the diameter, it may have a periodically varying thickness (axial thickness). In this case, the thickness of the sensor rotor 81 at the circumferential position facing the sensing portion 82 in the axial direction changes periodically every time the rotation angle of the rotor 30 changes by a predetermined angle.

Reference Signs List 1 motor (rotary electric machine), 10 motor housing (non-rotating portion), 30 rotor, 300 sensor adjacent portion, 301 first portion (base portion or specific portion, concave portion), 302 second portion (base portion or specific portion, convex portion), 81 sensor rotor, 810, 810A small diameter portion (part), 812, 812A large diameter portion ( part), 82 ... sensing part, 821 ... sensor coil (coil)

Claims

a rotor;
a non-rotating portion that rotatably supports the rotor;
a sensor rotor that rotates integrally with the rotor;
a sensing unit having a coil axially facing the sensor rotor;
The sensor rotor has radial protrusions and radial recesses at predetermined angles on an outer peripheral portion,
The rotor has a sensor adjacent portion axially adjacent to the sensor rotor from a side opposite to the sensing portion,
The sensor-adjacent portion includes a base portion and a specific portion that is axially uneven with respect to the base portion,
The sensor rotor has a magnetic shielding property that blocks magnetic flux that can pass from the side facing the sensing portion in the axial direction to the side facing the sensor adjacent portion in the axial direction,
When viewed in the axial direction from the coil of the sensing unit, among the recesses of the sensor rotor at the predetermined angles, the recesses overlap the recesses at the predetermined angle or at integral multiples of the predetermined angle in the circumferential direction. , the rotating electrical machine, wherein the base portion or the specific portion of the sensor adjacent portion is periodically arranged in the circumferential direction.
When the rotor rotates 360 degrees, the base portion and the specific portion of the sensor adjacent portion are aligned with the predetermined The rotary electric machine according to claim 1, arranged periodically for each angle or for each integral multiple of the predetermined angle in the circumferential direction.
A plurality of the specific parts are provided at different positions in the circumferential direction,
2. The rotating electric machine according to claim 1, wherein each of said specific portions overlaps a convex portion of said sensor rotor when viewed in the axial direction from said coil of said sensing portion.
4. The electric rotating machine according to claim 3, wherein at least one of the plurality of specific parts differs from the other specific parts in the form of unevenness in the axial direction.