JP6742210B2 - Positioning method for electric motor and resolver rotor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a technical field of an electric motor provided with a stator, a rotor rotated with respect to the stator, and a resolver having a resolver rotor, and a method of positioning the resolver rotor.

An electric motor mounted on a vehicle such as an electric vehicle is generally provided with a resolver that detects a rotation angle of a rotor. The resolver has a resolver rotor attached to a shaft that is a fulcrum of rotation of a rotor, and a resolver stator that is attached to a housing on the outer peripheral side of the resolver rotor.

The resolver detects the rotation angle of the rotor based on a change in the distance between the resolver rotor and the resolver stator which are rotated together with the rotor when the resolver stator is energized. Therefore, in order to ensure good detection accuracy of the resolver, the resolver rotor and the resolver stator must be properly positioned and attached.

Therefore, regarding the positioning of the resolver rotor, a positioning protrusion protruding inward in the radial direction from the insertion hole of the shaft in the resolver rotor is provided, and the positioning protrusion extends from one end to the other end of the shaft at a predetermined position in the circumferential direction of the shaft. There is an electric motor in which a positioning groove to be inserted is formed (for example, refer to Patent Document 1). When the positioning protrusion is inserted into the positioning groove and attached to the shaft, the resolver rotor is positioned in the circumferential direction with respect to the shaft.

JP, 2009-281762, A

By the way, in the structure in which the positioning groove is formed on the shaft of the rotor, the center of gravity of the rotor becomes more biased as the positioning groove has a larger formation area on the shaft, increasing the deviation (unbalance amount) of the rotation shaft of the rotor. Will end up.

Therefore, an object of the present invention is to suppress the unbalance amount of the rotor while positioning the resolver rotor on the shaft with high accuracy.

An electric motor according to the present invention is an electric motor that includes a stator, a rotor that is rotated with respect to the stator, and a resolver that detects a rotation angle of the rotor, and the rotor is a shaft that serves as a rotation fulcrum. The shaft has a large diameter portion and a small diameter portion that is continuous with the end surface in the axial direction of the large diameter portion and has a smaller diameter than the large diameter portion, and the end surface is formed as an abutting surface, The resolver has a resolver rotor in which an insertion hole into which the small diameter portion is inserted is formed, and a part of the small diameter portion in the axial direction is located at a position continuous with the large diameter portion with respect to the shaft of the resolver rotor. A positioning groove for performing positioning in a direction is formed, the resolver rotor is attached to the shaft in a state of being abutted against the abutting surface by the insertion of the small diameter portion into the insertion hole, and the resolver rotor includes: A positioning protrusion is provided that protrudes from the opening edge of the insertion hole, is bent when the small diameter portion is inserted into the insertion hole, and is at least partially inserted into the positioning groove.

As a result, the positioning projection is refolded and inserted into the positioning groove formed in a part of the small-diameter portion in the axial direction to perform positioning with respect to the shaft of the resolver rotor. Become.

In the above-described electric motor, it is desirable that a guide groove that is continuous with the positioning groove and that guides the positioning protrusion is formed in the large-diameter portion.

As a result, the positioning protrusion is guided by the guide groove and inserted into the positioning groove continuous with the guide groove.

In the above electric motor, it is preferable that the resolver rotor is formed by laminating a plurality of electromagnetic steel plates, and the positioning protrusion is provided on a part of the electromagnetic steel plates.

Thereby, the positioning protrusion is formed without increasing the number of parts.

In the above-mentioned electric motor, it is preferable that the positioning protrusion is provided on a part of the electromagnetic steel plate located closest to the abutting surface side in the resolver rotor.

As a result, the length of the positioning protrusion is shortened, and the formation region of the positioning protrusion is formed to a minimum size.

In the above-described electric motor, it is desirable that the positioning protrusion be formed by bending a part of the electromagnetic steel plate.

As a result, the positioning protrusion is formed by bending the electromagnetic steel plate.

In the above electric motor, it is preferable that the positioning protrusion has a curved surface portion that comes into contact with the large diameter portion when the small diameter portion is inserted into the insertion hole.

As a result, the curved surface portion formed into a curved surface is brought into contact with the large diameter portion, and the positioning protrusion is smoothly inserted into the positioning groove.

In the above-described electric motor, the positioning protrusion has a continuous portion that is continuous with the opening edge and a tip portion that is bent with respect to the continuous portion, and the curved surface is formed in the continuous portion and the continuous portion of the tip portion. It is desirable that the part be formed.

As a result, the curved surface portion of the positioning protrusion is located closest to the large diameter portion and is in contact with the large diameter portion.

A method for positioning a resolver rotor according to the present invention includes a stator, a large diameter portion whose end face in the axial direction is formed as an abutting surface, and a small diameter portion which is continuous with the end face and whose diameter is smaller than the large diameter portion. A rotor provided with a shaft having the shaft and rotated with respect to the stator with the shaft as a rotation fulcrum, and a resolver having a resolver rotor having an insertion hole formed therein and detecting a rotation angle of the rotor, In a motor in which a positioning groove is formed at a position continuous with the large diameter portion in a part of the small diameter portion in the axial direction, and the resolver rotor is provided with a positioning protrusion protruding from an opening edge of the insertion hole. A method of positioning the resolver rotor, wherein the small-diameter portion is inserted into the insertion hole of the resolver rotor, and when the small-diameter portion is inserted into the insertion hole, the positioning protrusion contacts the large-diameter portion. At least a part of the resolver rotor is bent and inserted into the positioning groove, a part of the resolver rotor is abutted against the abutting surface, and the resolver rotor is positioned with respect to the shaft.

As a result, the positioning projection is refolded and inserted into the positioning groove formed in a part of the small diameter portion in the axial direction, and the positioning of the resolver rotor with respect to the shaft is performed.

According to the present invention, while the positioning of the resolver rotor on the shaft is performed with high accuracy, the region where the positioning groove is formed in the rotor is reduced, and the amount of unbalance of the rotor can be suppressed.

2 to 12 show an embodiment of an electric motor of the present invention, which is an exploded perspective view of the electric motor. It is a perspective view which shows a part of shaft. It is an expanded sectional view near a positioning groove in the axial direction of a rotor. It is a sectional view of a resolver rotor and a shaft in a state before positioning is performed. It is an expanded sectional view showing the state where the resolver rotor was inserted in the small diameter part. It is an expanded sectional view showing the state where a curved surface part touched the wall surface which forms a guide groove. FIG. 6 is an enlarged cross-sectional view showing a state where a curved surface portion is slid on a wall surface forming a guide groove and is moved toward a positioning groove. FIG. 6 is an enlarged cross-sectional view showing a state in which a part of a continuous portion and a tip portion are inserted into a positioning groove. It is an expanded sectional view showing the state where the curved surface part touched the butting surface in a modification. FIG. 11 is an enlarged cross-sectional view showing a state in which a part of a continuous portion and a tip portion are inserted into a positioning groove in a modified example. It is an expanded sectional view of the resolver rotor in a modification. FIG. 10 is an enlarged cross-sectional view in the axial direction of a resolver rotor in which a curved surface portion is formed on a positioning protrusion in a modified example.

<Structure of electric motor>
Hereinafter, modes for carrying out the electric motor of the present invention will be described with reference to the accompanying drawings.

The electric motor 100 is mounted on a vehicle driven by electricity, such as an electric vehicle or a hybrid electric vehicle, and is used as a drive motor.

The electric motor 100 includes a housing 1, a stator 2, a rotor 3 rotated with respect to the stator 2, and a resolver 4 that detects a rotation angle of the rotor 3 (see FIG. 1 ).

The housing 1 has a box-shaped case body 5 that is open to one side and a cover body 6 that closes the opening of the case body 5. The internal space of the housing 1 is formed as a storage space 1a in which the stator 2 is stored. Support holes 5a and 6a and a fixing groove (not shown) are formed on a surface of the case body 5 facing the cover body 6 and an inner surface of the cover body 6, respectively.

The stator 2 has a cylindrical stator core 2a and a coil (not shown) wound around the stator core 2a. The stator core 2a is formed by laminating a plurality of electromagnetic steel plates, for example.

The rotor 3 has a shaft 7 serving as a rotation fulcrum and a cylindrical rotor core 8 fitted on the shaft 7. The rotor core 8 is formed by laminating a plurality of electromagnetic steel plates, for example. Inside the rotor core 8, a magnetic body such as a magnet (not shown) is arranged.

The resolver 4 has a cylindrical resolver stator 9 and a resolver rotor 10 arranged inside the resolver stator 9. The resolver stator 9 is fixed to the inner surface of the cover body 6, and the resolver rotor 10 is attached to the rotor 3. The resolver stator 9 has a resolver stator core 9a formed by laminating a plurality of electromagnetic steel plates, and a coil (not shown) wound around the resolver stator core 9a.

Subsequently, the configuration of the shaft 7 will be described in detail with reference to FIGS. 1 to 3.

The shaft 7 is supported by bearings 11 and 11 (see FIG. 1). The bearings 11 and 11 are fitted in fixing grooves formed in the case body 5 and the cover body 6, respectively, and the outer rings are fixed. Portions near both ends of the shaft 7 are inserted into the bearings 11 and 11, and both ends of the shaft 7 are inserted into the support hole 5a of the case body 5 and the support hole 6a of the cover body 6, respectively. The bearings 11, 11 have a function of receiving the load of the shaft 7 and smoothly rotating the shaft 7.

The shaft 7 has a large-diameter portion 12 and small-diameter portions 13, 13 that are continuous with both end surfaces of the large-diameter portion 12 in the axial direction and have a smaller diameter than the large-diameter portion 12. The central axes of the large diameter portion 12 and the small diameter portions 13, 13 are aligned. The rotor core 8 is externally fitted to the large diameter portion 12, and the resolver rotor 10 is attached to the one small diameter portion 13.

The shaft 7 is rotatably supported by the housing 1 by inserting the small diameter portions 13, 13 into the support hole 5a of the case body 5 and the support hole 6a of the cover body 6, respectively.

A positioning groove 13a for positioning the resolver rotor 10 in the circumferential direction is formed at a position in the axial direction of the small-diameter portion 13 to which the resolver rotor 10 is attached, in a position continuous with the large-diameter portion 12 (FIG. 2 and FIG. 2). 3). The positioning groove 13a is formed, for example, by cutting a part of the small diameter portion 13 with a cutting tool or the like. The positioning groove 13a is deepest at a position near the end on the abutting surface 12a side. The wall surface forming the positioning groove 13 a is formed in a concave gently curved surface on the outer peripheral surface side of the small diameter portion 13.

One end surface of the large diameter portion 12 in the axial direction is formed as an abutment surface 12a against which the axial end surface of the resolver rotor 10 abuts.

The large diameter portion 12 is formed with a guide groove 12b continuous with the positioning groove 13a. The guide groove 12b is formed, for example, by cutting a part of the large diameter portion 12 with a cutting tool or the like. The guide groove 12b has the deepest intermediate portion in the radial direction of the large diameter portion 12. The wall surface forming the guide groove 12b is formed in a gentle curved surface shape concave toward the abutting surface 12a.

The guide groove 12b may be formed simultaneously with the positioning groove 13a. That is, the large diameter portion 12 and the small diameter portion 13 may be continuously cut with a cutting tool or the like to form the guide groove 12b and the positioning groove 13a in the large diameter portion 12 and the small diameter portion 13, respectively. Accordingly, the guide groove 12b and the positioning groove 13a can be formed at the same time without increasing the work process for forming the guide groove 12b and the positioning groove 13a, and the working time can be shortened.

Subsequently, the configuration of the resolver rotor 10 will be described in detail with reference to FIGS. 1 and 3.

The resolver rotor 10 is formed by laminating a plurality of annular electromagnetic steel plates 10a. The electromagnetic steel plate 10a has, for example, an elliptical outer shape.

The resolver rotor 10 has a substantially circular insertion hole 10b penetrating in the axial direction. The small diameter portion 13 is inserted into the insertion hole 10b. The inner diameter of the insertion hole 10b is larger than the outer diameter of the small diameter portion 13, and a gap is formed between the insertion hole 10b and the small diameter portion 13.

An annular fixing ring 14 is press-fitted and externally fitted to the small diameter portion 13. The resolver rotor 10 is restricted from moving in the axial direction by the fixed ring 14.

Among the electromagnetic steel plates 10a constituting the resolver rotor 10, the electromagnetic steel plate 10a located closest to the abutting surface 12a is provided with the positioning projection 15 (see FIG. 3). The positioning protrusion 15 is formed by protruding a part of the electromagnetic steel plate 10a inward in the radial direction from the opening edge of the insertion hole 10b. The tip of the positioning protrusion 15 is inserted into the positioning groove 13a.

The positioning protrusion 15 has a continuous portion 15a continuous with the opening edge of the insertion hole 10b and a tip portion 15b continuous with the continuous portion 15a. The continuous portion 15a is in a state of extending in the radial direction of the electromagnetic steel plate 10a. The tip portion 15b is formed by bending the continuous portion 15a. The tip portion 15b is bent with respect to the continuous portion 15a so as to be positioned on the opposite side of the abutting surface 12a with respect to the continuous portion 15a. The leading end and the leading end 15b of the continuous portion 15a are located inside the positioning groove 13a.

A bent outer surface is formed as a curved surface portion 15d in the continuous portion 15c of the continuous portion 15a and the tip portion 15b. The curved surface portion 15d is in contact with the wall surface forming the positioning groove 13a.

<Resolver rotor positioning work>
The operation of positioning the resolver rotor 10 with respect to the shaft 7 will be described below with reference to FIGS. 4 to 8. The resolver rotor 10 is attached to the shaft 7 by inserting the small diameter portion 13 into the insertion hole 10b, and is positioned with respect to the shaft 7.

In the resolver rotor 10, the continuous portion 15a of the positioning projection 15 projects from the opening edge of the insertion hole 10b toward the abutting surface 12a in the state before positioning is performed, and the resolver rotor 10 approaches the central axis P as it approaches the tip. (See FIG. 4). The continuous portion 15a is inclined, for example, at an angle of approximately 75° (angle A shown in the drawing) with respect to the diameter of the resolver rotor 10. At this time, the tip portion 15b is located closer to the central axis P than the continuous portion 15a. The curved surface portion 15d is located closest to the abutting surface 12a of the positioning protrusion 15.

In the state described above, the resolver rotor 10 is fitted onto the small diameter portion 13 and the small diameter portion 13 is relatively inserted into the insertion hole 10b. At this time, the fixed ring 14 is press-fitted into the small-diameter portion 13, and the resolver rotor 10 is pressed by the fixed ring 14 and moved toward the abutting surface 12a (see FIG. 5). At this time, in the resolver rotor 10, the tip of the positioning projection 15 and a portion of the opening edge of the insertion hole 10b located opposite to the positioning projection 15 with respect to the center slide or come close to the outer peripheral surface of the small diameter portion 13. To be done.

The resolver rotor 10 may be moved to the abutting surface 12a side by being pressed by a jig or the like instead of the fixed ring 14. However, even when the resolver rotor 10 is moved using a jig or the like, it is necessary to insert the fixing ring 14 that restricts the axial movement of the resolver rotor 10 after positioning. Therefore, when the resolver rotor 10 is moved by being pressed by the fixing ring 14, the number of working steps is reduced and the working efficiency can be improved.

When the resolver rotor 10 is moved toward the abutting surface 12a, the continuous portion 15c of the positioning projection 15 is inserted into the guide groove 12b, and the curved surface portion 15d contacts the wall surface forming the guide groove 12b (see FIG. 6). reference).

When the resolver rotor 10 continues to move, the curved surface portion 15d slides on the wall surface forming the guide groove 12b and moves to the positioning groove 13a side (see FIG. 7). At this time, with the movement of the curved surface portion 15d toward the positioning groove 13a, the continuous portion 15a is gradually refolded in the direction in which the inclination angle becomes smaller with respect to the opening edge of the insertion hole 10b.

The resolver rotor 10 is further moved until the end face in the axial direction abuts against the abutting face 12a, and the continuous portion 15a is further refolded (see FIG. 8). The resolver rotor 10 is axially positioned with respect to the shaft 7 by having its end face in the axial direction abut against the abutting face 12a.

In a state where the resolver rotor 10 is abutted against the abutting surface 12a, the continuous portion 15a is refolded so as to extend in the radial direction of the resolver rotor 10, and a part of the continuous portion 15a and the tip portion 15b are inserted into the positioning groove 13a. ing. As a result, the resolver rotor 10 is positioned with respect to the shaft 7 in the circumferential direction.

When the resolver rotor 10 is moved in the direction approaching the abutting surface 12a, if at least a part of the positioning protrusion 15 is inserted into the positioning groove 13a, the resolver rotor 10 slides on the small-diameter portion 13 to move. The load applied to the resolver rotor 10 from the small diameter portion 13 is reduced, and the resolver rotor 10 pressed by the fixing ring 14 can be easily moved in the direction of approaching the abutting surface 12a. Therefore, the positioning groove 13a also has a function as a stress relief groove for releasing the stress generated in the fixing ring 14 when the resolver rotor 10 is pressed, and the pressing force of the fixing ring 14 on the resolver rotor 10 is reduced. It is possible to improve the workability in the positioning work for the shaft 7.

<Summary>
In the above-described electric motor 100, a positioning groove 13a for positioning the resolver rotor 10 in the circumferential direction with respect to the shaft 7 is formed in a part of the small diameter portion 13 in the axial direction, and the resolver rotor 10 has a small diameter portion 13 to the insertion hole 10b. A positioning protrusion 15 is provided which is bent at the time of insertion and at least a part of which is inserted into the positioning groove 13a.

As a result, the positioning projection 15 is refolded and inserted into the positioning groove 13a formed in a part of the small diameter portion 13 in the axial direction, and the resolver rotor 10 is positioned with respect to the shaft 7. Since the positioning projection 15 is refolded and inserted into the positioning groove 13a in this manner, it is not necessary to form a groove into which the positioning projection 15 is inserted from one end to the other end in the axial direction of the small diameter portion 13. The area where the positioning groove 13a is formed in the rotor 3 is small. Therefore, the unbalance amount of the rotor 3 can be suppressed while positioning the resolver rotor 10 with respect to the shaft 7 with high accuracy. Further, the strength of the shaft 7 can be improved.

Further, in the above-described electric motor 100, the large diameter portion 12 is formed with the guide groove 12b which is continuous with the positioning groove 13a and guides the positioning protrusion 15. As a result, the positioning protrusion 15 is inserted into the guide groove 12b and then into the positioning groove 13a continuous with the guide groove 12b, so that the positioning protrusion 15 can be reliably inserted into the positioning groove 13a.

In the electric motor 100 described above, the resolver rotor 10 is formed by laminating a plurality of electromagnetic steel plates 10a, and the positioning protrusion 15 is provided on a part of the electromagnetic steel plate 10a. Thus, the positioning protrusion 15 is provided on a part of the electromagnetic steel plate 10a of the resolver rotor 10, so that the positioning protrusion 15 can be formed without increasing the number of parts.

In the above-described electric motor 100, the positioning protrusion 15 is provided on a part of the electromagnetic steel plate 10a located closest to the abutting surface 12a of the resolver rotor 10. As a result, the length of the positioning protrusion 15 is shortened, so that the formation region of the positioning groove 13a can be formed to the minimum size.

In the electric motor 100 described above, the positioning protrusion 15 is formed by bending a part of the electromagnetic steel plate 10a. Thus, the positioning protrusion 15 is formed by bending the electromagnetic steel plate 10a, so that the positioning protrusion 15 can be formed by a simple construction method.

In the above-described electric motor 100, the positioning protrusion 15 has the curved surface portion 15d that comes into contact with the large diameter portion 12 when the small diameter portion 13 is inserted into the insertion hole 10b. As a result, the curved surface portion 15d formed in the curved shape in the positioning protrusion 15 comes into contact with the large diameter portion 13, so that the positioning protrusion 15 can be smoothly inserted into the positioning groove 13a.

In the above-described electric motor 100, the positioning projection 15 has the continuous portion 15a continuous with the opening edge of the resolver rotor 10 and the tip portion 15b bent with respect to the continuous portion 15a. The continuous portion 15a and the tip portion 15b are provided. The curved surface portion 15d is formed on the continuous portion 15c. As a result, the curved surface portion 15d is formed in the continuous portion 15c of the continuous portion 15a and the tip portion 15a bent with respect to the continuous portion 15a, so that the curved surface portion 15d of the positioning projection 15 has the largest diameter portion 12 side. The curved surface portion 15d can be surely brought into contact with the large-diameter portion 12 at the position.

<Modification>
In the above electric motor 100, for example, the following modified examples are possible.

Although the example in which the guide groove 12b is formed in the large diameter portion 12 has been described above, the guide groove 12b may not be formed in the large diameter portion 12 (see FIGS. 9 and 10). In this case, since the guide groove 12b is not formed in the large diameter portion 12, the unbalance amount of the rotor 3 can be further suppressed.

In the configuration in which the guide groove 12b is not formed in the large diameter portion 12, when the resolver rotor 10 is inserted into the small diameter portion 13 and moved in the direction of approaching the abutting surface 12a, the curved surface portion 15d of the abutting protruding portion 15 is It contacts the abutting surface 12a (see FIG. 9). When the resolver rotor 10 is continuously moved, the curved surface portion 15d is slid on the end surface of the large diameter portion 12 and moved to the positioning groove 13a side. At this time, as the curved surface portion 15d moves to the positioning groove 13a side, the continuous portion 15a is gradually re-bent in a direction in which the inclination angle becomes smaller with respect to the opening edge of the insertion hole 10b. When the resolver rotor 10 is moved until the end face in the axial direction is abutted against the abutting face 12a, part of the continuous portion 15a and the tip portion 15b are inserted into the positioning groove 13a (see FIG. 10).

Further, although the example in which the positioning protrusion 15 is provided as a part of the electromagnetic steel plate 10a forming the resolver rotor 10 has been described above, the positioning protrusion 15 is provided on the electromagnetic steel plate 10a as a member different from the electromagnetic steel plate 10a. It may be joined.

Furthermore, in the above, the example in which the positioning protrusion 15 has the continuous portion 15a continuous to the opening edge of the insertion hole 10b and the tip portion 15b bent with respect to the continuous portion 15a has been shown. 15 may be composed of only the continuous portion 15a (see FIG. 11). In this case, the tip surface of the continuous portion 15a may be formed as the curved surface portion 15d (see FIG. 12).

The shapes of the guide groove 12b and the positioning groove 13a are not limited to the above shapes. For example, the wall surface forming the guide groove 12b and the positioning groove 13a may not be formed in a curved shape, but may be formed by a plurality of flat surfaces in different directions. Further, the guide groove 12b and the positioning groove 13a are not limited to the deepest shape in the middle part in the radial direction of the abutting surface 12a and the middle part in the axial direction of the small diameter part 13, but may be formed in other shapes. Good.

1... Housing, 2... Stator, 3... Rotor, 4... Resolver, 7... Shaft, 10... Resolver rotor, 10a... Electromagnetic steel plate, 10b... Insertion hole, 12... Large diameter part, 12a... Abutting surface, 12b ... guide groove, 13... small diameter part, 13a... positioning groove, 14... fixing ring, 15... positioning protrusion, 15a... continuous part, 15b... tip part, 15c... continuous part, 15d... curved surface part, 100... electric motor

Claims (8)

A motor comprising a stator, a rotor rotated with respect to the stator, and a resolver for detecting a rotation angle of the rotor,
The rotor has a shaft serving as a rotation fulcrum,
The shaft has a large-diameter portion and a small-diameter portion that is continuous with the end surface in the axial direction of the large-diameter portion and has a smaller diameter than the large-diameter portion,
The end surface is formed as an abutting surface,
The resolver has a resolver rotor having an insertion hole into which the small diameter portion is inserted,
A positioning groove for positioning in the circumferential direction with respect to the shaft of the resolver rotor is formed at a position in the axial direction of the small diameter portion at a position continuous with the large diameter portion,
The resolver rotor is attached to the shaft in a state of being abutted against the abutting surface by inserting the small diameter portion into the insertion hole,
An electric motor, wherein the resolver rotor is provided with a positioning protrusion protruding from an opening edge of the insertion hole, bent when the small-diameter portion is inserted into the insertion hole, and at least partially inserted into the positioning groove. The electric motor according to claim 1, wherein a guide groove that is continuous with the positioning groove and that guides the positioning protrusion is formed in the large-diameter portion. The resolver rotor is formed by laminating a plurality of electromagnetic steel plates,
The electric motor according to claim 1, wherein the positioning protrusion is provided on a part of the electromagnetic steel plate. The electric motor according to claim 3, wherein the positioning protrusion is provided on a part of the electromagnetic steel plate located closest to the abutting surface side in the resolver rotor. The electric motor according to claim 3 or 4, wherein the positioning protrusion is formed by bending a part of the electromagnetic steel plate. The said positioning protrusion has a curved surface part which contacts the said large diameter part at the time of inserting the said small diameter part in the said insertion hole, The claim|item 1, claim 2, claim 3, claim 4 or claim 5. Electric motor. The positioning protrusion has a continuous portion continuous to the opening edge and a tip portion bent with respect to the continuous portion,
The electric motor according to claim 6, wherein the curved surface portion is formed in a continuous portion between the continuous portion and the tip portion. A shaft having a stator, a large diameter portion whose end face in the axial direction is formed as an abutting surface, and a small diameter portion continuous with the end face and having a diameter smaller than the large diameter portion is provided, and the shaft is used as a fulcrum of rotation. A rotor that rotates with respect to the stator, and a resolver that has a resolver rotor having an insertion hole formed therein and that detects a rotation angle of the rotor are provided, and a part of the small-diameter portion in the axial direction has the above-mentioned structure. A method for positioning the resolver rotor in an electric motor, wherein a positioning groove is formed at a position continuous with a large diameter portion, and the resolver rotor is provided with a positioning protrusion protruding from an opening edge of the insertion hole,
Insert the small diameter portion into the insertion hole of the resolver rotor,
At the time of inserting the small diameter portion into the insertion hole, the positioning protrusion contacts the large diameter portion and is bent so that at least a part is inserted into the positioning groove, and a part of the resolver rotor is the abutting surface. A method for positioning a resolver rotor, which is abutted against a shaft, and in which the resolver rotor is positioned with respect to the shaft.

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