JP2023098102A - motor - Google Patents

Abstract

To provide a motor capable of stably rotating a rotor.SOLUTION: A motor comprises a rotor 20 and a stator. The rotor rotates around an axis of rotation. The stator is arranged on a radially outer side of the rotor. The rotor has a shaft 20, rotor cores 22a and 22b, a rotor magnet, a plate-like end plate 24, and a plate-like end ring 25. The shaft extends along the axis of rotation. The plurality of rotor cores surround the shaft from the radially outside and are arranged in an axial direction. The rotor magnet is fixed to the rotor core. The end plate is arranged on at least one of the axially outer sides of the rotor cores, and has a plate through-hole into which the shaft is press-fitted. The end ring is in contact with an axially outer surface of the end plate, and has a ring through-hole 251 into which the shaft is press-fitted. An insertion pressure on the shaft of the end ring is larger than the insertion pressure on the shaft of the end plate.SELECTED DRAWING: Figure 2

Description

The present invention relates to motors.

A conventional motor has a rotor that rotates about an axis of rotation. The rotor surrounds the shaft from the outside in the radial direction, and includes a plurality of rotor cores arranged in the axial direction, and a plate-like end plate arranged axially outside the rotor core and having a shaft through-hole into which the shaft is press-fitted ( For example, see Patent Document 1).

JP 2018-88748 A

However, in conventional motors, there is a possibility that the press force applied to the shaft through-hole of the shaft during rotation of the rotor may decrease, causing the end plate to shift in the axial direction, resulting in unstable rotation of the rotor.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a motor capable of stably rotating a rotor.

An exemplary motor of the present invention comprises a rotor and a stator. The rotor rotates around the axis of rotation. The stator is arranged radially outside the rotor. The rotor has a shaft, a rotor core, rotor magnets, plate-like end plates, and plate-like end rings. The shaft extends along the axis of rotation. A plurality of rotor cores surround the shaft from the outside in the radial direction and are arranged in the axial direction. A rotor magnet is fixed to the rotor core. The end plate is arranged on at least one of the axial outer sides of the rotor core and has a plate through-hole into which the shaft is press-fitted. The end plate has a ring through hole that contacts the axial outer surface of the end plate and into which the shaft is press-fitted. The press force of the end ring on the shaft is greater than the press force of the end plate on the shaft.

According to the exemplary invention, it is possible to provide a motor that can stably rotate the rotor.

FIG. 1 is a longitudinal sectional view of a motor according to an embodiment of the invention. FIG. 2 is a perspective view of the rotor of the motor according to the embodiment of the invention. FIG. 3 is an exploded perspective view of the rotor of the motor according to the embodiment of the invention. FIG. 4 is an exploded perspective view of part of a motor according to an embodiment of the invention. FIG. 5 is a perspective view of the center plate of the motor according to the embodiment of the invention.

Exemplary embodiments of the invention are described in detail below with reference to the drawings. The direction in which the rotation axis J of the motor 1 extends shown in FIG. 1 is simply referred to as the "axial direction", and the radial direction and the circumferential direction about the rotation axis J of the motor 1 are simply referred to as the "radial direction" and the "circumferential direction". call. Note that "axial direction", "radial direction", and "circumferential direction" are names used merely for explanation, and do not limit actual positional relationships and directions.

Hereinafter, motors according to embodiments of the present invention will be described with reference to the drawings. It should be noted that the scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention.

<1. Configuration of Motor>
A motor 1 according to an exemplary embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a motor 1 of one embodiment. 2 is a perspective view of the rotor 20, and FIG. 3 is an exploded perspective view of the rotor 20. FIG.

A motor 1 is mounted on a vehicle as a power source for a hybrid vehicle (HV), a plug-in hybrid vehicle (PHV), an electric vehicle (EV), or the like.

The motor 1 is an inner rotor type motor. The motor 1 is housed inside a housing (not shown) and includes a rotor 20 and a stator 30 . The rotor 20 rotates around the rotation axis J. As shown in FIG.

<2. Configuration of Stator>
The stator 30 is arranged to face the rotor 20 radially outward with a gap therebetween. A stator 30 is fixed to the housing. The stator 30 has a stator core 31 and multiple coils 32 . The stator core 31 surrounds the rotor 20 from the radial outside. The stator core 31 has an axially extending cylindrical core back (not shown) and a plurality of teeth (not shown) extending radially inward from the core back. The core back is formed by laminating a plurality of magnetic bodies such as electromagnetic steel sheets in the axial direction. A plurality of teeth are arranged at equal intervals over one round along the circumferential direction.

A plurality of coils 32 are attached to respective teeth of stator core 31 via insulators (not shown). A plurality of coils 32 are arranged in the circumferential direction.

<3. Configuration of Rotor>
The rotor 20 has a shaft 21 , rotor cores 22 a and 22 b , rotor magnets 23 , two end plates 24 , two end rings 25 and a center plate 26 .

The shaft 21 extends along the rotation axis J and rotates about the rotation axis J. As shown in FIG. The shaft 21 is formed in a cylindrical shape and has a hollow portion 21a, a communication hole 21b, and a concave groove portion 21c. The hollow portion 21a is arranged inside the shaft 21 and extends in the axial direction.

The communication hole 21b radially penetrates the shaft 21 and communicates with the hollow portion 21a. The communication hole 21b allows the hollow portion 21a and the outside of the shaft 21 to communicate with each other. The recessed groove portion 21c is formed on the inner peripheral surface of the shaft 21 so as to be recessed radially outward and extends in the circumferential direction. The communication hole 21b is arranged inside the concave groove portion 21 .

The shaft 21 is rotatably supported by bearings (not shown). The bearings are, for example, ball bearings. The bearings are held in a housing (not shown) that houses the motor 1 .

The rotor cores 22a and 22b surround the shaft 21 from the outside in the radial direction and are arranged in plurality in the axial direction. In this embodiment, two rotor cores 22a and 22b are arranged, and an annular center plate 26 is arranged between the rotor cores 22a and 22b. Although two rotor cores 22a and 22b are provided in this embodiment, two or more may be provided.

The rotor cores 22a and 22b are formed by laminating a plurality of magnetic bodies such as annular magnetic steel sheets in the axial direction. The rotor cores 22a and 22b each have an insertion hole 221, a rotor flow hole 222, and a magnet insertion hole 223.

The insertion hole 221 extends along the rotation axis J and axially penetrates the rotor cores 22a and 22b. Shaft 21 is inserted into insertion hole 221 .

The rotor flow hole 222 is arranged radially outside the insertion hole 221 and axially penetrates the rotor cores 22a and 22b. A plurality of rotor circulation holes 222 are arranged at regular intervals in the circumferential direction. In this embodiment, eight rotor flow holes 222 are provided, but the number may be other than eight.

The magnet insertion hole 223 axially penetrates the rotor cores 22a and 22b. The rotor magnet 23 is inserted inside the magnet insertion hole 223 . Thereby, the rotor magnet 23 is fixed to the rotor cores 22a and 22b. Note that the rotor magnet 23 may be fixed to the outer peripheral surfaces of the rotor cores 22a and 22b.

<4. Configuration of End Plate and End Ring>
4 is an exploded perspective view of the end plate 24 and the end ring 25. FIG. The two end plates 24 are disc-shaped and arranged axially outside the rotor core 22a and axially outside the rotor core 22b. The end plate 24 is arranged on the rotation axis J and has a plate through hole 241 extending therethrough in the axial direction. The shaft 21 is press-fitted into the plate through-hole 241 .

The end plate 24 has projections 242 and recesses 243 . The projecting portion 242 axially protrudes from the outer peripheral portion of the axially outer surface of the end plate 24 . The protrusion 242 is formed in an annular shape surrounding the plate through hole 241 . The recess 243 is axially recessed from the axial end surface of the protrusion 242 . In this embodiment, four recesses 243 are provided at equal intervals in the circumferential direction. A plate flow hole 244 is formed through the bottom surface of the recess 243 in the axial direction.

The two end rings 25 are formed in an annular shape and contact the axial outer surface of each end plate 24 respectively. The end ring 25 has a ring through hole 251 into which the shaft 21 is press-fitted.

The end ring 25 has a protrusion 252 . The convex portion 252 protrudes radially outward from the radial outer peripheral surface of the end ring 25 and is arranged inside the concave portion 243 . In this embodiment, four protrusions 252 are provided at equal intervals in the circumferential direction.

In this embodiment, the end ring 25 on the rotor core 22a side functions to hold (prevent displacement) the rotor cores 22a and 22b in the axial direction and to hold (prevent rotation) the end plate 24 in contact with the end face of the rotor core 22a in the circumferential direction. ing. The end ring 25 on the rotor core 22b side functions as a circumferential retainer (rotation stop) for the end plate 24 in contact with the end face of the rotor core 22b. As shown in FIG. 1, a flange 21d is formed at the lower end of the shaft 21. The flange 21d extends axially from the rotor cores 22a and 22b, the end plate 25 in contact with the rotor core 22b, and the end ring 24. It is held so that it does not shift.

The rotor cores 22 a and 22 b are axially sandwiched between and fixed by two end plates 24 . The end rings 25 press the end plates 24 toward the rotor cores 22a and 22b to prevent the end plates 24 from slipping in the axial direction. Thereby, the rotor 20 can be stably rotated.

At this time, at least the pressure force of the end ring 25 on the rotor core 22 a side to the shaft 21 is greater than the pressure force of the end plate 24 to the shaft 21 . Thereby, the end plate 24 can be fixed more firmly in the axial direction.

For example, the end plate 24 is press-fitted onto the shaft 21 by pressing. The end ring 25 on the rotor core 22a side is press-fitted onto the shaft 21 by shrink fitting. By shrink-fitting the end ring 25 onto the shaft 21, the end ring 25 can be press-fitted onto the shaft 21 with a larger press force. Moreover, by shrink-fitting the end ring 25 onto the shaft 21, the workability of assembling the rotor 20 is improved. Both the end ring 25 on the rotor core 22a side and the end ring 25 on the rotor core 22b side may be press-fitted onto the shaft 21 by shrink fitting.

When the end ring 25 is in contact with the end plate 24 , the projection 252 fits into the recess 243 and the end plate 24 is circumferentially fixed by the end ring 25 . As a result, it is possible to prevent the end plate 24 from shifting in the circumferential direction when the shaft 21 rotates.

A gap may be formed in the circumferential direction between the convex portion 252 and the concave portion 243 . As a result, even if the shape of the projection 252 varies, the projection 252 can be reliably fitted into the recess 243 .

Further, the end plate 24 is formed with a protrusion 242 , and the outer peripheral portion of the end plate 24 is thicker in the axial direction than the inner peripheral portion of the end plate 24 . As a result, the end plate 24 receives a larger pressing force in the axial direction from the end ring 25 to the outer peripheral portion than to the inner peripheral portion. This makes it possible to further prevent the end plate 24 from slipping in the axial direction.

The bottom surface of the concave portion 243 and the convex portion 252 face each other in the axial direction via a gap S, and the gap S is open at its radially outer end (see FIG. 2).

<5. Configuration of Center Plate>
FIG. 5 is a perspective view of the center plate 26. FIG. The center plate 26 is disc-shaped and has a center through hole 261 , a center circulation hole 262 , and a center concave portion 263 . The center through-hole 261 is arranged on the rotation axis J and axially penetrates the center plate 26 . The shaft 21 is inserted through the center through hole 261 .

The center recess 263 is formed by axially recessing one axial end face of the center plate 26 at the peripheral edge of the center through-hole 261. The center circulation hole 262 is arranged on the bottom surface of the center recess and extends in the circumferential direction. Multiple are arranged at intervals. In this embodiment, the center circulation holes 262 are provided at eight locations at regular intervals in the circumferential direction.

The center plate 26 has a center oil channel 265 (see FIG. 1). The center oil flow path 265 is composed of the center circulation hole 262 and the center recess 263 . When the center plate 26 is brought into contact with the rotor core 22a, a gap is formed between the bottom surface of the center recess 263 and the axial end face of the rotor core 22a on the rotor core 22b side. The communication hole 21 b of the shaft 21 is open facing the center concave portion 263 . Thereby, the center oil flow path 265 communicates the communication hole 21b, the rotor flow hole 222 of the rotor core 22a, and the rotor flow hole 222 of the rotor core 22b.

<6. Configuration of oil passage>
The motor 1 has an oil passage 40 through which oil circulates (see FIG. 1). The oil is contained within a housing (not shown) containing the motor 1 . In this specification, the term "oil passage" means a route of oil.

Oil is a cooling medium that cools the motor 1 . In order to function as lubricating oil and cooling oil for the motor 1, it is preferable to use an oil equivalent to automatic transmission fluid (ATF), which has a relatively low viscosity.

The oil passage 40 is composed of the hollow portion 21 a of the shaft 21 , the center oil passage 265 , the rotor circulation hole 222 and the gap S.

Centrifugal force is applied to the oil supplied to the hollow portion 21a as the rotor 20 rotates. As a result, the oil is continuously splashed to the center oil flow path 265 through the communication hole 21b. Further, as the oil scatters, the pressure inside the hollow portion 21a becomes negative, and the oil inside the hollow portion 21a is sucked toward the communication hole 21b. At this time, by providing the recessed groove portion 21c, the oil is accumulated in the recessed groove portion 21c. Therefore, oil can be stably supplied to the outside of the shaft 21 through the communication hole 21b.

The oil that has flowed from the center oil flow path 265 into the rotor circulation holes 222 of the rotor cores 22a and 222 of the rotor cores 22b flows axially outward and scatters axially outwards of the rotor cores 22a and 22b.

The oil scattered axially outward from the rotor cores 22a and 22b flows into the gap S through the plate circulation hole 244 and is jetted from the radially outer end of the gap S toward the stator 30 (see FIG. 2). The oil that reaches the stator 30 takes heat from the stator 30 .

<7. Others>
The embodiments of the present invention have been described above. It should be noted that the scope of the present invention is not limited to the above-described embodiments. The present invention can be implemented with various modifications without departing from the gist of the invention. Further, the above-described embodiments can be combined arbitrarily as appropriate.

In this embodiment, two end plates 24 are provided on both axially outer sides of the rotor cores 22a and 22b, but they may be provided on only one of the axially outer sides of the rotor cores 22a and 22b. In this case, the other axially outer rotor cores 22a, 22b can be axially fixed to the rotor cores 22a, 22b using, for example, nuts and washers.

The motor of the present invention can be used, for example, as a power source for automobiles and the like.

1 Motor 20 Rotor 21 Shaft 21a Hollow Part 21b Communication Hole 21c Groove Part 21d Flange 22a, 22b Rotor Core 23 Rotor Magnet 24 End Plate 25 End Ring 26 Center Plate 30 Stator 31 Stator Core 32 Coil 40 Oil Path 221 Insertion Hole 222 Rotor Flow Hole 223 Magnet insertion hole 241 Plate through hole 242 Projection 243 Recess 244 Plate circulation hole 251 Ring through hole 252 Protrusion 261 Center through hole 262 Center circulation hole 263 Center recess 265 Center oil flow path J Rotation shaft S Clearance

Claims (8)

a rotor that rotates about a rotation axis;
a stator arranged radially outward of the rotor,
The rotor is
a shaft extending along the axis of rotation;
a plurality of rotor cores surrounding the shaft from the outside in the radial direction and arranged in the axial direction;
a rotor magnet fixed to the rotor core;
a plate-shaped end plate disposed on at least one of the axially outer sides of the rotor core and having a plate through hole into which the shaft is press-fitted;
a plate-shaped end ring having a ring through-hole in contact with the axial outer surface of the end plate and into which the shaft is press-fitted;
The motor, wherein the press force of the end ring to the shaft is greater than the press force of the end plate to the shaft. 2. The motor of claim 1, wherein the end rings are shrink-fitted to the shaft. The end plate is
an annular protrusion projecting axially from the outer peripheral portion of the axial outer surface;
a concave portion recessed in the axial direction from the axial end face of the protrusion;
The end ring is
3. The motor according to claim 1, further comprising a convex portion that protrudes radially outward from the radial outer peripheral surface and is arranged inside the concave portion. 4. The motor according to claim 3, wherein a gap is formed in a circumferential direction between said convex portion and said concave portion. 5. The motor according to claim 1, wherein the outer peripheral portion of said end plate is thicker in the axial direction than the inner peripheral portion of said end plate. the bottom surface of the concave portion and the convex portion face each other in the axial direction with a gap therebetween,
6. The motor according to any one of claims 1 to 5, wherein the gap has an open radial outer end. further comprising an annular center plate disposed between the axially adjacent rotor cores;
The shaft is formed in a cylindrical shape having a hollow inside,
having a communication hole penetrating in a radial direction and communicating with the hollow portion;
The rotor core is
an insertion hole extending along the rotation axis and axially penetrating through which the shaft is inserted;
a rotor flow hole arranged radially outside the insertion hole and penetrating in the axial direction;
7. The motor according to claim 1, wherein said center plate has a center oil flow path that communicates said communicating hole and said rotor communicating hole. 8. The motor according to claim 7, wherein said shaft has a circumferentially extending recessed groove on its inner peripheral surface, and said communication hole is arranged in said recessed groove.

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