JP7492231B2 - Rotating electric machine and manufacturing method thereof - Google Patents

Description

The present invention relates to a rotating electric machine and a manufacturing method for a rotating electric machine.

For example, a rotating electric machine (motor) for a power steering system or the like includes a rotating shaft, a rotor, and a stator. An opening is formed in the rotor, into which the rotating shaft is inserted, and the rotor is fixed to the rotating shaft. For example, Patent Document 1 describes a rotating electric machine in which multiple rotor cores are arranged in the axial direction of the rotating shaft. Patent Document 1 describes that the rotor cores are attached offset from each other in the rotational direction of the rotating shaft, thereby forming a step skew.

JP 2014-236592 A

In such rotating electric machines, multiple rotor cores are fixed to the rotating shaft, but if the fixing force of the rotor cores to the rotating shaft is insufficient, the rotor will not be able to follow the rotation of the rotating shaft, which may cause the motor to malfunction. Therefore, in rotating electric machines in which multiple rotor cores are attached to the rotating shaft, there is a need to prevent the rotor cores from spinning freely.

The present invention has been made in consideration of the above, and aims to provide a rotating electric machine in which multiple rotor cores are attached to a rotating shaft, a method for manufacturing the rotating electric machine, and a rotor unit that can prevent the rotor cores from spinning freely.

In order to solve the above-mentioned problems and achieve the object, a rotating electric machine according to the present disclosure comprises a rotating shaft, and a rotor including a first rotor core and a second rotor core attached to the rotating shaft and aligned in the axial direction of the rotating shaft, wherein the first rotor core has a recess formed on its surface facing the second rotor core, and the second rotor core has a convex portion formed on its back surface facing the first rotor core that fits into the recess of the first rotor core, the first rotor core has a plurality of recesses formed lined up in the circumferential direction on its surface facing the second rotor core, and three or more of the recesses are formed so as to include a plurality of pairs of the recesses adjacent in the circumferential direction, the recesses are formed so that the angle between any pair of the recesses is different from the angle between any other pair of the recesses, the first rotor core and the second rotor core are the same rotor core, and the angle between the recesses is set by a skew angle .

The first rotor core has a plurality of recesses formed in a circumferential line on the surface facing the second rotor core, and preferably has three or more recesses formed so as to include a plurality of pairs of recesses adjacent to each other in the circumferential direction, and the recesses are preferably formed so that the angle between any pair of the recesses is different from the angle between any other pair of the recesses.

It is preferable that some of the recesses of the first rotor core are through holes that penetrate from the surface on the second rotor core side to the back surface on the opposite side, and that the recesses other than the through holes are depressions that do not penetrate to the back surface.

It is preferable that the second rotor core has a recess formed on the surface opposite to the back surface of the first rotor core at a position that overlaps with the protrusion in the axial direction.

The rotor further includes a third rotor core provided on the opposite side of the second rotor core from the first rotor core side in the axial direction, and it is preferable that the third rotor core has a convex portion formed on the back surface facing the second rotor core, into which the concave portion of the second rotor core is fitted.

In order to solve the above-mentioned problems and achieve the object, a manufacturing method for a rotating electric machine according to the present disclosure is a manufacturing method for a rotating electric machine including a first rotor core having a recess formed on a front surface, a second rotor core having a protrusion formed on a back surface, and a rotating shaft, wherein the first rotor core has a plurality of recesses formed side by side in a circumferential direction on a surface facing the second rotor core, three or more of the recesses are formed so as to include a plurality of pairs of the recesses adjacent in the circumferential direction, the recesses are formed so that an angle between one pair of the recesses is different from an angle between another pair of the recesses, and the plurality of first rotor cores Some of the recesses are through holes that penetrate from the surface on the second rotor core side to the back surface on the opposite side, and the method includes a first step of pressing and attaching the first rotor core to the rotating shaft while inserting a pin into the through hole to position the first rotor core, and a second step of pressing and attaching the second rotor core to the rotating shaft from the same direction as the first rotor core was attached in the first step, while fitting the protrusions of the second rotor core into the recesses of the first rotor core so that the first rotor core and the second rotor core form a step skew.

According to the present invention, in a rotating electric machine in which multiple rotor cores are attached to a rotating shaft, it is possible to prevent the rotor cores from spinning freely.

FIG. 1 is a cross-sectional view of a rotating electrical machine according to this embodiment. FIG. 2 is a schematic cross-sectional view of the rotor unit according to the present embodiment. FIG. 3 is a schematic diagram of a rotating shaft according to the present embodiment. FIG. 4 is a schematic diagram of a rotor core according to the present embodiment. FIG. 5 is a schematic diagram of a rotor core according to the present embodiment. FIG. 6 is a schematic diagram of a rotor core according to the present embodiment. FIG. 7 is a schematic diagram of a plate member according to the present embodiment. FIG. 8 is a schematic diagram showing the positional relationship of each rotor core. FIG. 9 is a schematic diagram showing the positional relationship of each rotor core. FIG. 10 is a diagram for explaining a method of assembling the rotor core.

Below, a preferred embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment described below.

(Overall configuration of rotating electric machine)
1 is a cross-sectional view of a rotating electric machine according to the present embodiment. The rotating electric machine 100 according to the present embodiment is a motor, more specifically, a brushless motor. The rotating electric machine 100 is used, for example, in an electric steering device of a vehicle, and applies a steering assist force to a steering shaft of the vehicle. However, the use of the rotating electric machine 100 is not limited thereto.

As shown in FIG. 1, the rotating electric machine 100 includes a casing 10, a stator 20, a rotor unit 30, a busbar unit 40, a holding member 50, a substrate 60, a cover member 70, and bearings B1 and B2. Hereinafter, the direction along the axial direction of the rotating shaft 32 described below is referred to as the Z direction. One of the directions along the Z direction is referred to as the Z1 direction, and the other direction along the Z direction, i.e., the direction opposite to the Z1 direction, is referred to as the Z2 direction.

As shown in FIG. 1, the casing 10 is a housing that houses the stator 20, the rotor unit 30, the busbar unit 40, the holding member 50, and the substrate 60. The casing 10 is a hollow member that opens on the Z1 side, and in this embodiment, is a cylindrical member that is circular when viewed from the Z direction. The casing 10 includes a bottom 12 and a side 14. The bottom 12 constitutes the bottom surface of the casing 10 on the Z2 side. The bottom 12 has an opening 12A through which the rotating shaft 32 described below is inserted. In addition, a bearing B1, which is a bearing, is provided on the surface of the bottom 12. The bearing B1 is provided so as to surround the opening 12A when viewed from the Z direction, and is fixed to the bottom 12. The side 14 constitutes the side surface of the casing 10. The side 14 is provided so as to surround the outer edge of the bottom 12, and extends from the outer edge of the bottom 12 in the Z1 direction. The casing 10 houses the stator 20, rotor unit 30, busbar unit 40, holding member 50, and substrate 60 in a space SP surrounded by the bottom 12 and side 14.

The casing 10 is made of an aluminum alloy material. More specifically, the casing 10 is made of ADC12 material, which is specified by JIS.

The stator 20 is a stator of the rotating electric machine 100. The stator 20 is provided in the casing 10, i.e., in the space SP of the casing 10. The stator 20 includes a stator core 22 and a stator coil 24. The stator core 22 is the core of the stator 20, and a through hole 22A penetrating in the Z direction is formed at the center position when viewed from the Z direction. The stator core 22 is made of a magnetic material, and more specifically, is made of an iron-based member. An iron-based member is a member whose main component is iron. More specifically, the stator core 22 according to this embodiment is made of an electromagnetic steel plate. The stator core 22 is made by stacking members made of electromagnetic steel plate in the Z direction. However, the stator core 22 is not limited to being made of electromagnetic steel plate, and is not limited to being configured by stacking members in the Z direction.

The stator coil 24 is a coil of the stator 20. The stator coil 24 includes U-phase, V-phase, and W-phase electromagnetic coils. The stator coil 24 is wound around the stator core 22.

The stator 20 is fixed to the casing 10 by contacting the outer peripheral surface 20A with the inner peripheral surface 10A of the casing 10. In other words, the stator 20 is fitted into the casing 10 by being press-fitted (pressed) into the casing 10.

The rotor unit 30 is a rotor of the rotating electric machine 100. The rotor unit 30 is provided in the space SP of the casing 10. The rotor unit 30 includes a rotating shaft 32 and a rotor 34. The rotor 34 has a through hole penetrating in the Z direction at the center position when viewed from the Z direction. The rotating shaft 32 is a shaft, and is inserted into an opening of the rotor 34 (opening 91 of the rotor core 80 described later) and fixed to the rotor 34. The rotor unit 30 is provided such that the outer peripheral surface of the rotor 34 is provided in the through hole 22A of the stator core 22. The rotor unit 30 is provided in the through hole 22A so that the axial direction of the rotating shaft 32 is along the Z direction. The rotor unit 30 is also provided in the through hole 22A so as to be rotatable with respect to the stator 20. Since the rotor unit 30 is inserted into the through hole 22A in this way, it can be said that the stator 20 is provided on the outer periphery of the rotor 34. The rotor unit 30 rotates around the central axis of the rotating shaft 32 along the Z direction due to electromagnetic interaction with the stator 20. The detailed configuration of the rotating shaft 32 and the rotor 34 will be described later.

A gear portion 36 is attached to the end of the rotating shaft 32 on the Z2 side. The gear portion 36 meshes with a mating gear (not shown) that is connected to the steering shaft, and transmits the rotation of the rotating shaft 32 to the steering shaft. A detector 38 is attached to the end of the rotating shaft 32 on the Z1 side. The detector 38 is a member for detecting the rotation speed of the rotor unit 30, and is, for example, a magnet or a magnetic sensor.

The busbar unit 40 is provided on the Z1 side of the stator coil 24 within the space SP of the casing 10. The busbar unit 40 is a plate-shaped (disk-shaped in this case) member that includes multiple busbars and a busbar holder. The busbars are conductive members and are connected to the U-phase, V-phase, and W-phase of the stator coil 24. The busbar holder is an insulating member that covers the busbars.

The holding member 50 is provided on the Z1 direction side of the busbar unit 40 in the space SP of the casing 10. The holding member 50 is a plate-shaped (disk-shaped here) member that holds the bearing B2. The holding member 50 is fixed to the casing 10, for example, with its outer peripheral surface in contact with the inner peripheral surface 10A of the casing 10. That is, the holding member 50 is press-fitted (pressed) into the casing 10. However, the holding member 50 is not limited to being press-fitted into the casing 10. The holding member 50 has a through hole 50A formed at its center position when viewed from the Z direction. The through hole 50A is provided with the bearing B2, which is a bearing. Since the bearing B2 is fixed to the holding member 50, it can also be said that the bearing B2 is fixed to the casing 10 via the holding member 50.

The rotating shaft 32 of the rotor unit 30 is rotatably supported by bearings B1 and B2. That is, the portion of the rotating shaft 32 on the Z2 side is rotatably inserted into bearing B1, and the portion on the Z1 side of the portion inserted into bearing B1 is rotatably inserted into bearing B2.

The substrate 60 is provided on the Z1 direction side of the holding member 50 within the space SP of the casing 10. The substrate 60 is a circuit board on which the circuit of the ECU (Electronic Control Unit) of the rotating electric machine 100 is provided. The substrate 60 is electrically connected to the busbar of the busbar unit 40 via a connection portion 52 provided between the substrate 60 and the busbar unit 40.

The cover member 70 is provided at the end of the casing 10 on the Z1 direction side. The cover member 70 includes a cover 72 and a terminal portion 74. The cover 72 is a cover that closes the opening on the Z1 direction side of the space SP of the casing 10. The cover 72 is attached to the casing 10 so as to cover the opening at the end of the casing 10 on the Z1 direction side. The terminal portion 74 is attached to the cover 72. The terminal portion 74 includes wiring (not shown) that is electrically connected to the circuit of the board 60, and a terminal that is connected to the wiring.

(Configuration of rotor unit)
Next, a detailed configuration of the rotor unit 30 will be described. Fig. 2 is a schematic cross-sectional view of the rotor unit according to this embodiment. As shown in Fig. 2, the rotor unit 30 includes a rotor cover part 35 in addition to a rotating shaft 32 and a rotor 34. The rotor cover part 35 covers the rotor 34.

The rotor 34 has a plurality of rotor cores 80 arranged in the Z direction. The rotor cores 80 are members that constitute the core of the rotor unit 30. The rotor cores 80 are made of a magnetic material (paramagnetic material), and more specifically, are made of iron-based materials. The iron-based materials are materials whose main component is iron. The rotor core 80 is made of plate members P stacked in the Z direction. In this embodiment, the plate members P are electromagnetic steel plates. However , the rotor core 80 is not limited to being made of plate members P stacked, and may be, for example, an integral member. The rotor core 80 has an opening 91 formed in the center when viewed from the Z direction, penetrating from one surface 80a in the Z direction to the back surface 80b, which is the other surface in the Z direction.

In the example of FIG. 2, the rotor 34 has three rotor cores 80A, 80B, and 80C aligned in the Z direction. However, the number of rotor cores 80 is not limited to three as long as there is more than one, and may be, for example, two or four or more.

A magnet M is attached to the rotor core 80. The magnet M is a permanent magnet (ferromagnetic material). The magnets M are attached to the outer periphery of the rotor core 80, and are arranged in a line in the circumferential direction. The circumferential direction here refers to the circumferential direction when the Z direction is the axial direction. The magnets M are arranged in a line in the circumferential direction, so that they are arranged over the entire circumferential section of the rotor core 80, but there may be a gap between adjacent magnets M in the circumferential direction where no magnet M is provided. Note that the magnets M are not limited to being attached to the outer periphery of the rotor core 80, and may be arranged, for example, in an opening formed in the rotor core 80.

3 is a schematic diagram of the rotating shaft according to this embodiment. As shown in FIG. 3, the rotating shaft 32 has a protrusion N formed on the outer circumferential surface 32a, which protrudes radially outward from the outer circumferential surface 32a. The radial direction here refers to the radial direction when the Z direction is the axial direction. In this embodiment, the protrusion N is streaked extending in the Z direction, and is formed in a circumferential direction on the outer circumferential surface 32a. The protrusion N in this embodiment can also be said to be knurling (knurling). As shown in FIG. 2, the rotating shaft 32 is fixed to the rotor core 80 by being inserted into the opening 91 of each rotor core 80 to which the magnet M is attached. Specifically, the inner diameter of the opening 91 of the rotor core 80 is smaller than the longest part of the outer diameter of the rotating shaft 32 (the part where the protrusion N is formed). Therefore, when the rotating shaft 32 is inserted into the opening 91 of the rotor core 80, the protrusion N comes into contact with the inner peripheral surface of the opening 91 of the rotor core 80, receives a load from the inner peripheral surface of the opening 91 of the rotor core 80, and undergoes elastic deformation and plastic deformation. The protrusion N deforms in this manner, thereby fixing the rotating shaft 32 to the rotor core 80. However, the fixing method of the rotating shaft 32 to the rotor core 80 is not limited to this. For example, the number of protrusions N does not need to be multiple, and the shape of the protrusion N does not need to be a stripe extending in the Z direction. In addition, the protrusion N does not need to be provided on the rotating shaft 32. In this case, for example, the entire outer diameter of the rotating shaft 32 may be made larger than the inner diameter of the opening 91 of the rotor core 80, and the rotating shaft 32 may be press-fitted into the opening 91 of the rotor core 80. By pressing the rotating shaft 32 into the rotor core 80, the outer peripheral surface of the rotating shaft 32 and the inner peripheral surface of the opening 91 of the rotor core come into contact over the entire circumferential area and are tightly fitted. That is, the rotating shaft 32 is fixed to the rotor core 80 (rotor 34) because at least a portion of the outer circumferential surface 32a contacts the inner circumferential surface of the opening 91 of the rotor core 80 (rotor 34).

In this way, the rotor core 80 is fixed to the rotating shaft 32 by inserting the rotating shaft 32 into the opening 91, and rotates together with the rotating shaft 32 as the rotating shaft 32 rotates. However, if the rotor core 80 is not fixed to the rotating shaft 32 sufficiently, it may not rotate together with the rotating shaft 32 and may not be able to follow the rotation of the rotating shaft 32, resulting in idling. An example of a case where the fixing to the rotating shaft 32 is insufficient is, for example, a case where a rotating shaft 32 having a protrusion N is inserted into three or more rotor cores 80. In this case, for example, the rotating shaft 32 is inserted into the rotor core 80A from the end on the Z2 direction side, and is inserted into the rotor core 80B from the end on the opposite side, the Z1 direction side, and then the rotating shaft 32 is inserted into the rotor core 80C from the end on the Z1 direction side. In this case, the last inserted rotor core 80C is inserted from the same side as the rotor core 80B, so that it is located in the part of the rotating shaft 32 where the rotor core 80B has already been inserted and the protrusion N has been crushed. Therefore, the fixing force of the rotor core 80C to the rotating shaft 32 may be insufficient, and the rotor core 80C may spin freely without being able to follow the rotation of the rotating shaft 32. Note that cases where the fixing to the rotating shaft 32 is insufficient are not limited to the above example, and may also occur, for example, when there are two rotor cores 80 or when the protrusion N is not formed on the rotating shaft 32.

In contrast, the rotor core 80 according to this embodiment is formed with the recessed portion 92 and the protruding portion 94 described below, so that the rotor core 80 can be prevented from spinning freely even if the fixing force of the rotor core 80C to the rotating shaft 32 is insufficient. The detailed shape of the rotor core 80 will be described below.

(Rotor core shape)
4 to 6 are schematic diagrams of the rotor core according to this embodiment. FIG. 4 is a perspective view of the rotor core 80A, FIG. 5 is a top view of the rotor core 80A, and FIG. 6 is a cross-sectional view taken along line A-A in FIG. 5. In the following, the shape of the rotor core 80A will be described as a representative of each rotor core 80, but in the example of this embodiment, since all the rotor cores 80 have the same shape, the rotor cores 80B and 80C also have the same shape as the rotor core 80A. As shown in FIGS. 4 and 5, the rotor core 80A has a protrusion 90 formed on its outer peripheral surface (side surface) 80c. The protrusion 90 is a portion that protrudes radially outward from the outer peripheral surface 80c, and is formed on the outer peripheral surface 80c from the front surface 80a side to the back surface 80b side. A plurality of protrusions 90 are provided in the circumferential direction on the outer peripheral surface 80c. The protrusions 90 are formed to attach magnets M, and the magnets M are attached to positions between the protrusions 90 adjacent to each other in the circumferential direction of the outer peripheral surface 80c.

As shown in FIG. 5, recesses 92 are formed on the surface 80a of the rotor core 80A. The recesses 92 here may refer to either a hole that penetrates from the surface 80a to the opposite back surface 80b, or a depression that does not penetrate to the back surface 80b. A plurality of recesses 92 are formed in the surface 80a in a line in the circumferential direction. Each recess 92 is located on the circumference of an imaginary circle C centered on the center O of the rotor core 80A as viewed from the Z direction. Furthermore, if the center of the recess 92 as viewed from the Z direction is the center Oa, the length from the center O to the center Oa as viewed from the Z direction is equal for each recess 92. In this specification, "equal" and "same" also include differences of a general tolerance.

In this embodiment, three recesses 92A, 92B, and 92C are formed as the recess 92, and the recesses 92A, 92B, and 92C are arranged in this order in the circumferential direction. Here, the angle between the recess 92A and the recess 92B, that is, the angle between the straight line connecting the center O and the center Oa of the recess 92A and the straight line connecting the center O and the center Oa of the recess 92B, as viewed from the Z direction, is defined as angle θ1. The angle between the recess 92B and the recess 92C, that is, the angle between the straight line connecting the center O and the center Oa of the recess 92B and the straight line connecting the center O and the center Oa of the recess 92C, as viewed from the Z direction, is defined as angle θ2. The angle between the recess 92C and the recess 92A, that is, the angle between the straight line connecting the center O and the center Oa of the recess 92C and the straight line connecting the center O and the center Oa of the recess 92A, as viewed from the Z direction, is defined as angle θ3. In this case, angles θ1, θ2, and θ3 are not all the same angle, and at least some of the angles are different from the other angles. In the example of FIG. 5, angles θ1 and θ3 are the same angle, but angle θ2 is a different angle from angles θ1 and θ3. In the example of FIG. 5, angle θ2 is larger than angles θ1 and θ3. Angles θ1, θ2, and θ3 are set according to the number of recesses 92 and the skew angle. For example, when the number of recesses 92 is three and the skew angle is 6 degrees, angles θ1 and θ3 are 114 degrees, and angle θ2 is 132 degrees.

In this way, the recesses 92A, 92B, and 92C are provided at positions where the angles θ1, θ2, and θ3 are not all the same depending on the skew angle, and thus function as positioning of the step skew. The rotor core 80A is formed with three or more recesses 92 so as to include a plurality of pairs of recesses 92 adjacent to each other in the circumferential direction (three recesses 92A and 92B, recesses 92B and 92C, and recesses 92C and 92A in the example of FIG. 5), and each recess 92 is formed so that the angle between the pair of recesses 92 (angle θ2 in the example of FIG. 5) is different from the angle between the other pairs of recesses 92. By forming the recesses 92 in this way, it can function appropriately as positioning of the step skew. The number of recesses 92 is not limited to three and may be any number, and may be two or four or more. The number of recesses 92 may be one.

In the example of FIG. 5, the recesses 92 are circular when viewed from the Z direction, but the shape may be arbitrary. The size of the recesses 92 may also be arbitrary. It is preferable that the size and shape of each recess 92 are the same.

6, some of the recesses 92 are through holes that penetrate from the front surface 80a to the back surface 80b, and the remaining recesses 92 are recesses that do not penetrate to the back surface 80b. In the example of this embodiment, the recess 92C is a through hole that penetrates to the back surface 80b, and the recesses 92A and 92B are recesses that do not penetrate to the back surface 80b. It is preferable that the recess 92C penetrates from the front surface 80a to the back surface 80b along the Z direction. Thus, in this embodiment, the recesses 92A and 92B are recesses and the recess 92C is a through hole, but this is not limited thereto, and the positional relationship between the through holes and the recesses in the multiple recesses 92 is arbitrary, and for example, the recess 92C may be a recess and either the recess 92A or 92B may be a through hole. In addition, the number of through holes and recesses in the multiple recesses 92 may also be arbitrary, and for example, all of them may be recesses.

As shown in FIG. 6, the rotor core 80A has a convex portion 94 formed on the back surface 80b. The convex portion 94 is formed at a position that overlaps with a concave portion 92 (a concave portion 92 other than a through hole) that is a recess formed on the front surface 80a in the Z direction. In the example of FIG. 6, the concave portions 92A and 92B are concaves, and the concave portion 92C is a through hole. Therefore, the convex portion 94A is formed at a position on the back surface 80b that overlaps with the concave portion 92A of the front surface 80a in the Z direction, and the convex portion 94B is formed at a position that overlaps with the concave portion 92B of the front surface 80a in the Z direction. In other words, the center line AXA of the concave portion 92A along the Z direction passes through the center of the convex portion 94A, and the center line AXB of the concave portion 92B along the Z direction passes through the center of the convex portion 94B. The positional relationship between the convex portion 94A, the convex portion 94B, and the concave portion 92C on the back surface 80b is the same as the positional relationship between the concave portion 92A, the concave portion 92B, and the concave portion 92C on the front surface 80a.

The shape and size of the protrusions 94 may also be arbitrary, but the protrusions 94 are of a size and shape that can fit into the recesses 92. It is preferable that the size and shape of each protrusion 94 are the same.

As described above, the rotor core 80 has a recess 92 formed on the front surface 80a and a protrusion 94 formed on the back surface 80b. FIG. 7 is a schematic diagram of a plate member according to this embodiment. As described above, the rotor core 80 is formed by stacking a plurality of plate members P. In this case, for example, as shown in FIG. 7, plate members P having a recess 92 formed on one surface and a protrusion 94 formed on the other surface may be stacked in the Z direction to form a rotor core 80 having a recess 92 formed on the front surface 80a and a protrusion 94 formed on the back surface 80b. However, this is not limited to this, and the plate members P without the recess 92 or protrusion 94 may be stacked to form a rotor core, and then the recess 92 and the protrusion 94 may be formed in the rotor core.

(Positional relationship between rotor cores)
Next, the positional relationship of each rotor core 80 in the rotor unit 30 will be described. Figures 8 and 9 are schematic diagrams showing the positional relationship of each rotor core. Figure 8 shows a state in which the rotor cores 80 are lined up in the Z direction, and Figure 9 shows the fitting relationship between the recessed portions 92 and the protruding portions 94 of each rotor core 80. Note that while the rotor cores 80 are separated from each other in Figure 8, when actually assembled into the rotor unit 30, it is preferable that the surfaces of the rotor cores 80 contact each other as shown in Figure 2.

In the rotor unit 30, adjacent rotor cores 80 in the Z direction are fitted together with recesses 92 and protrusions 94 formed on the opposing surfaces. That is, the recesses 92 formed on the surface 80a of one rotor core 80 are fitted together with the protrusions 94 formed on the back surface 80b of the other rotor core 80. The fitting method between the recesses 92 and the protrusions 94 is arbitrary, and may be any of a tight fit, intermediate fit, and clearance fit. A detailed description is given below.

As shown in FIG. 8, in the rotor unit 30, the rotor cores 80A and 80B are attached so that the surface 80a of the rotor core 80A as the first rotor core faces the back surface 80b of the rotor core 80B as the second rotor core. More specifically, the rotor core 80B is attached offset in the circumferential direction R with respect to the rotor core 80A so as to form a step skew. As a result, the recess 92C on the surface 80a of the rotor core 80A and the protrusion 94A on the back surface 80b of the rotor core 80B are coaxial, and the protrusion 94A of the rotor core 80B is disposed within the recess 92C of the rotor core 80A, so that the recess 92C and the protrusion 94A fit together. In addition, the recess 92A on the front surface 80a of the rotor core 80A and the protrusion 94B on the back surface 80b of the rotor core 80B are coaxial, and the protrusion 94B of the rotor core 80B is disposed within the recess 92A of the rotor core 80A, so that the recess 92A and the protrusion 94B fit together. Note that the recess 92B on the front surface 80a of the rotor core 80A and the recess 92C on the back surface 80b of the rotor core 80B are not coaxial but are misaligned.

In addition, in the rotor unit 30, the rotor cores 80B and 80C are attached so that the surface 80a of the rotor core 80B as the second rotor core faces the back surface 80b of the rotor core 80C as the third rotor core. More specifically, the rotor core 80C is attached offset in the circumferential direction R with respect to the rotor core 80B so as to form a step skew. As a result, the recess 92A on the surface 80a of the rotor core 80B and the protrusion 94B on the back surface 80b of the rotor core 80C are coaxial, and the protrusion 94B of the rotor core 80C is disposed within the recess 92A of the rotor core 80B, so that the recess 92A and the protrusion 94B fit together. In addition, the recess 92C on the front surface 80a of the rotor core 80B and the protrusion 94A on the back surface 80b of the rotor core 80C are coaxial, and the protrusion 94A of the rotor core 80C is disposed within the recess 92C of the rotor core 80B, so that the recess 92C and the protrusion 94A fit together. Note that the recess 92B on the front surface 80a of the rotor core 80B and the recess 92C on the back surface 80b of the rotor core 80C are not coaxial but are misaligned.

Because the rotor cores 80A and 80B are fitted with the recesses 92 and protrusions 94, even if the rotor cores 80A and 80B are not sufficiently fixed to the rotating shaft 32, the rotor cores 80 can follow the rotation of the rotating shaft 32 through the portion that is fitted with the other rotor core 80, preventing the rotor cores 80 from spinning freely. Similarly, because the rotor cores 80B and 80C are fitted with the recesses 92 and protrusions 94, even if the rotor cores 80B and 80C are not sufficiently fixed to the rotating shaft 32, the rotor cores 80 can follow the rotation of the rotating shaft 32 through the portion that is fitted with the other rotor core 80, preventing the rotor cores 80 from spinning freely. In addition, because the rotor cores 80A, 80B, and 80C are attached in the above-mentioned positional relationship, they form a step skew that is shifted by the skew angle.

As shown in FIG. 9, in this embodiment, of the pair of recesses 92 (recesses 92B, 92C) that form an angle θ2 different from angles θ1 and θ3, the recess 92C on the opposite side to the direction R in which the rotor core 80 is shifted is a through hole. As a result, when the rotor core 80B is attached to the rotor core 80A by shifting it in the direction R, the recess 92C, not the protrusion 94 of the rotor core 80A, is positioned at a position shifted from the recess 92B of the rotor core 80A, so that the rotor cores 80 can be properly assembled by suppressing interference between the protrusion 94 and the surface of the rotor core 80A.

(Rotor core assembly method)
Next, a method for assembling the rotor core 80 will be described. Fig. 10 is a diagram for explaining the method for assembling the rotor core. As shown in step S10 of Fig. 10, in this assembling method, the end 32t1 of the rotating shaft 32 is inserted into the opening 91 of the rotor core 80A from the front surface 80a side of the rotor core 80A, and the rotating shaft 32 is fixed to the rotor core 80A. At this time, a positioning pin PN is inserted into a recess 92C, which is a through hole of the rotor core 80A, and the rotating shaft 32 is inserted into the rotor core 80A while positioning the rotor core 80A.

Next, as shown in step S12, the end 32t2 of the rotating shaft 32 opposite to the end 32t1 of the rotor core 80A is inserted into the opening 91 of the rotor core 80B from the rear surface 80b side of the rotor core 80B, and the rotating shaft 32 is fixed to the rotor core 80B. At this time, a positioning pin PN is inserted into the recess 92C of the rotor core 80B, and the rotor core 80B is positioned relative to the rotor core 80A so that the rotor core 80B is shifted by a skew angle relative to the rotor core 80A, while the rotating shaft 32 is inserted into the rotor core 80B. This allows the recess 92C of the rotor core 80A to be properly fitted with the protrusion 94A of the rotor core 80B, and the recess 92A of the rotor core 80A to be properly fitted with the protrusion 94B of the rotor core 80B, coaxially. In this way, the recess 92C, which is a through hole, has a function of fitting with the protrusion 94, as well as a function of positioning during assembly.

Next, as shown in step S14, the end 32t2 of the rotating shaft 32 to which the rotor cores 80A and 80B are fixed is inserted into the opening 91 of the rotor core 80C from the rear surface 80b side of the rotor core 80C, and the rotating shaft 32 is fixed to the rotor core 80C. At this time, a positioning pin PN is inserted into the recess 92C of the rotor core 80C, and the rotating shaft 32 is inserted into the rotor core 80B while positioning the rotor core 80C relative to the rotor core 80B so that the rotor core 80C is shifted by the skew angle relative to the rotor core 80B. This allows the recess 92A of the rotor core 80B to be properly fitted to the protrusion 94B of the rotor core 80C, and the recess 92C of the rotor core 80B to be properly fitted to the protrusion 94A of the rotor core 80C, coaxially.

By inserting the rotating shaft 32 into the rotor cores 80A, 80B, and 80C in this manner, the rotor cores 80A, 80B, and 80C are aligned in the Z direction while inserted into the rotating shaft 32, and the rotor unit 30 is manufactured as shown in step S16. The rotating electric machine 100 is manufactured by assembling the rotor unit 30 and the casing 10 and stator 20 shown in FIG. 1. In the example of FIG. 10, the rotor core 80A is inserted from the end 32t1 side, and the rotor cores 80B and 80C are inserted from the end 32t2 side, but this is not limited thereto. For example, the rotating shaft 32 may be inserted into all of the rotor cores 80A, 80B, and 80C from the end 32t1 side or the end 32t2 side.

As described above, the rotating electric machine 100 (rotor unit 30) according to this embodiment includes a rotating shaft 32 and a rotor 34 including a first rotor core (rotor core 80A in this embodiment) and a second rotor core (rotor core 80B in this embodiment) attached to the rotating shaft 32 and aligned in the axial direction (Z direction) of the rotating shaft 32. The rotor core 80A has a recess 92 formed on the surface 80a on the rotor core 80B side, and the rotor core 80B has a protrusion 94 formed on the back surface 80b on the rotor core 80A side, which fits into the recess 92 of the rotor core 80A. In the rotating electric machine 100 according to this embodiment, the rotor core 80A and the rotor core 80B are fitted together at the recess 92 and the protrusion 94, so that even if one of the rotor cores is not sufficiently fixed to the rotating shaft 32, for example, the rotor core can follow the rotation of the rotating shaft 32 via the other rotor core. Therefore, the rotating electric machine 100 according to this embodiment can prevent the rotor core 80 from spinning freely.

The first rotor core (rotor core 80A) has a number of recesses 92 arranged in a circumferential direction on its surface 80a facing the second rotor core (rotor core 80B). In the rotating electric machine 100 according to this embodiment, the recesses 92 formed in the circumferential direction allow the recesses 92 to be fitted with the protrusions 94 of the mating rotor core 80B, so that free rotation of the rotor core 80 can be more appropriately suppressed.

At least one of the multiple recesses 92 of the first rotor core (rotor core 80A) is a through hole penetrating from the surface 80a on the second rotor core (rotor core 80B) side to the back surface 80b on the opposite side. A protrusion 94 is formed on the back surface 80b of the rotor core 80A at a position overlapping with the recess 92 (depression) other than the through hole in the Z direction (axial direction). The rotor core 80A has a through hole and a non-penetrating depression, and the protrusion 94 is formed on the opposite side of the depression. Therefore, according to the rotating electric machine 100 according to this embodiment, in addition to fitting with the protrusion 94, the through hole can appropriately position the rotor core 80 when assembling it. Furthermore, by forming the protrusion 94 on the opposite side of the depression, rotor cores 80 of the same shape can be used as rotor cores 80A and 80B, and an increase in the number of parts can be suppressed. Furthermore, for example, when there are three or more rotor cores 80, even if a skew is added, the presence of the through hole makes it possible to assemble the rotor cores without interference between the protrusions and the recesses. Additionally, each rotor core 80 can be made to have the same shape, reducing design costs.

The first rotor core (rotor core 80A) has three or more recesses 92 formed so as to include a plurality of pairs of recesses 92 adjacent to each other in the circumferential direction. The recesses 92 are formed in rotor core 80A so that the angle between a pair of recesses 92 (angle θ2 in this embodiment) is different from the angles between other pairs of recesses 92 (angles θ1 and θ3 in this embodiment). In the rotating electric machine 100 according to this embodiment, the recesses 92 are formed in this manner, so that the recesses 92 can function not only to fit with the protrusions 94, but also as a positioning device when forming a step skew.

In addition, the second rotor core ( rotor core 80B) has a recess 92 formed on the front surface 80a opposite to the back surface 80b of the first rotor core (rotor core 80A) at a position that overlaps with the protrusion 94 in the Z direction (axial direction). Therefore, rotor cores 80 of the same shape can be used as rotor cores 80A and 80B, and an increase in the number of component types can be suppressed.

The rotor 34 further includes a third rotor core (rotor core 80C) that is provided on the opposite side of the second rotor core (rotor core 80B) from the first rotor core (rotor core 80A) in the Z direction (axial direction). The rotor core 80C has a protrusion 94 formed on the back surface 80b on the rotor core 80B side, into which the recess 92 of the rotor core 80B is fitted. According to the rotating electric machine 100 of this embodiment, the rotor cores 80B and 80C are also fitted together, so that even when there are three or more rotor cores 80, the free rotation of the rotor core 80 can be more appropriately suppressed.

The rotating shaft 32 is fixed to the rotor 34 by contacting at least a portion of the outer peripheral surface 32a with the inner peripheral surface of the rotor 34 (the inner peripheral surface of the opening 91 of the rotor core 80). According to the rotating electric machine 100 of this embodiment, even if the fixing between the rotating shaft 32 and the rotor core 80 is insufficient, the rotor cores 80 are fitted together, so that the free rotation of the rotor core 80 can be appropriately suppressed.

In addition, the manufacturing method of the rotating electric machine 100 according to this embodiment manufactures a rotating electric machine 100 including a first rotor core (rotor core 80A) having a recess 92 formed on the front surface 80a, a second rotor core having a protrusion formed on the back surface 80b, and a rotating shaft 32. This manufacturing method includes a first step of press-fitting the rotor core 80A to the rotating shaft 32 and a second step of press-fitting the rotor core 80B to the rotating shaft 32 from the same direction as the rotor core 80A was attached in the first step while fitting the protrusion 94 of the rotor core 80B into the recess 92 of the rotor core 80A. According to this manufacturing method, the idling of the rotor core 80 can be appropriately suppressed. More specifically, if the rotor core 80 is inserted multiple times so as to pass through the same place on the rotating shaft 32, the inserted part of the rotating shaft 32 may be deformed, and the idling retention force of the rotor core 80 may be reduced. In contrast, with this manufacturing method, rotor cores 80 are fitted together with their protruding and recessed portions, preventing the rotor cores 80 from spinning freely.

Although the embodiments and examples of the present invention have been described above, the embodiments are not limited to the contents of these embodiments. The above-mentioned components include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-mentioned components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-mentioned embodiments.

30 rotor unit 32 rotating shaft 34 rotor 80, 80A, 80B, 80C rotor core 80a front surface 80b rear surface 92, 92A, 92B, 92C recess 94, 94A, 94B protrusion 100 rotating electric machine

Claims (5)

A rotation axis;
a rotor attached to the rotating shaft and including a first rotor core and a second rotor core aligned in an axial direction of the rotating shaft;
The first rotor core has a recess formed on a surface thereof facing the second rotor core,
The second rotor core has a convex portion formed on a back surface thereof on the side of the first rotor core, the convex portion being fitted into a concave portion of the first rotor core,
the first rotor core has a surface facing the second rotor core, the surface being provided with a plurality of recesses arranged in a circumferential direction, three or more recesses being formed so as to include a plurality of pairs of the recesses adjacent to each other in the circumferential direction, and the recesses are formed so that an angle between any pair of the recesses is different from an angle between any other pair of the recesses;
the first rotor core and the second rotor core are the same rotor core,
The angle between the recesses is set by a skew angle.
Rotating electric motor. 2. The rotating electric machine according to claim 1, wherein some of the multiple recesses of the first rotor core are through holes that penetrate from the surface on the second rotor core side to the back surface on the opposite side, and the recesses other than the through holes are depressions that do not penetrate to the back surface. 3 . The rotating electric machine according to claim 1 , wherein the second rotor core has a recess formed on a front surface opposite to a back surface on the first rotor core side at a position overlapping with the protrusion in the axial direction. 4 . The rotor further includes a third rotor core provided on an opposite side of the second rotor core from the first rotor core in the axial direction,
The rotating electric machine according to claim 3 , wherein the third rotor core is formed on a back surface thereof facing the second rotor core with a protrusion into which the recess of the second rotor core is fitted. A method for manufacturing a rotating electric machine including a first rotor core having a recess formed on a front surface, a second rotor core having a protrusion formed on a rear surface, and a rotating shaft, the method comprising the steps of:
the first rotor core has a surface facing the second rotor core, the surface being provided with a plurality of recesses arranged in a circumferential direction, three or more recesses being formed so as to include a plurality of pairs of the recesses adjacent to each other in the circumferential direction, and the recesses are formed so that an angle between any pair of the recesses is different from an angle between any other pair of the recesses;
Some of the recesses of the first rotor core are through holes that penetrate from a surface on the second rotor core side to a back surface on the opposite side,
a first step of inserting a pin into the through hole to position the first rotor core and press-fitting the first rotor core onto the rotating shaft;
a second step of press-fitting and attaching the second rotor core to the rotating shaft from the same direction as the first rotor core was attached in the first step, while fitting the protrusion of the second rotor core into the recess of the first rotor core so that the first rotor core and the second rotor core form a step skew;
A method for manufacturing a rotating electric machine, comprising:

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