Motor

Abstract

To provide a technique for efficiently performing rotor balance adjustment without using additional parts.SOLUTION: A motor 2 comprises a rotor shaft 8 having a flange 12 at one end and a nut 16, which can be fastened, at the other end, and a rotor 4 attached to the rotor shaft 8 by the flange 12 and the nut 16. The outer peripheral edge of at least one of the flange 12 and the nut 16 has balance adjustment work-pieces 13, 19 and balance adjustment holes 13a, 19a that extend a predetermined length in the axial direction of the rotor shaft 8 and protrude radially outward from the rotor shaft 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a motor. [Background technology]

[0002] The motor comprises a rotor and a stator. The rotor rotates around the rotor shaft. To balance the rotor along the axial direction of the rotor shaft, balance adjustment is performed by cutting or drilling end rings or balance correction plates attached to the rotor shaft at the axial ends of the rotor (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-118308 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the contact state between the rotor and shaft can change due to shocks and vibrations such as cutting the end plate for balance adjustment, as well as the fastening operation, and in some cases it may be necessary to repeat the balance adjustment process.

[0005] The present specification provides a technique that allows rotor balancing to be performed efficiently without additional parts. [Means for solving the problem]

[0006] The technology disclosed in this specification is embodied in a motor. The motor includes a rotor shaft having a flange at one end and a nut at the other end, and a rotor attached to the rotor shaft by the flange and the nut. At least one of the flange and the nut has a balance adjustment processing portion and a balance adjustment hole on the outer peripheral edge thereof, which extend a predetermined length along the axial direction of the rotor shaft and protrude radially outward from the rotor shaft.

[0007] This motor has a machined portion of at least one of the flange and the nut and a balance adjustment hole. The balance adjustment hole allows the balance of the rotor to be corrected or adjusted. Therefore, the rotor does not require any additional parts for balance adjustment other than the parts necessary to attach the rotor to the rotor shaft.

[0008] Furthermore, since no additional parts for balancing are attached to the rotor shaft of this motor, the axial length of the entire motor is prevented from being increased by these parts. [Brief explanation of the drawings]

[0009] [Figure 1] 4 is a cross-sectional view showing a portion to be machined for balance adjustment and a balance adjustment hole in a rotor and a rotor shaft. FIG. [Figure 2] FIG. 4 is an enlarged cross-sectional view showing a balance adjustment hole formed in a processed portion. [Figure 3] FIG. 10 is a cross-sectional view showing another embodiment of the balance adjustment hole. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a motor according to the present disclosure will be described with reference to the accompanying drawings. In this specification, the term "axial direction" refers to the axial direction of the rotor shaft, and the term "radial direction" refers to the radial direction of the rotor shaft.

[0011] In this specification, the application of the motor is not particularly limited, but examples include an in-vehicle motor that drives the wheels of an electric vehicle such as an HEV or BEV. The in-vehicle motor can also be used together with an inverter, a gear set, etc. to form an e-axle, thereby forming a drive device for the electric vehicle.

[0012] 1 shows a cross section of a motor 2 including a rotor 4 and a rotor shaft 8. The motor 2 also includes a stator (not shown) and is housed in a motor case (not shown).

[0013] The rotor 4 is formed into a cylindrical body with a shaft hole 6 at its center that extends in the axial direction along the axis x of the rotation shaft of the rotor 4. The rotor 4 is not particularly limited, but may be formed, for example, by laminating electromagnetic steel sheets. The rotor 4 has a plurality of holes that extend in the axial direction around the shaft hole 6, and a magnet is inserted into each hole (not shown). The rotor 4 also has a refrigerant flow path 7 that takes in the refrigerant circulating inside the rotor shaft 8 and circulates it in the axial direction.

[0014] A rotor shaft 8 is attached to the shaft hole 6 of the rotor 4. The rotor shaft 8 is not particularly limited, but may be, for example, a hollow shaft extending along the axial direction of the rotor 4. The rotor shaft 8 includes a main body 10 housed within the rotor 4, and a flange 12 extending axially from one end face 4a of the rotor 4 and protruding radially outward from the rotor shaft 8. The rotor 4 also includes a fastening portion 14 protruding axially from the other end face 4b of the rotor 4, to which a nut 16 is fastened.

[0015] The flange 12 protrudes a predetermined amount from the main body 10 of the rotor shaft 8 radially outward of the rotor shaft 8 and has a flange base 12a that abuts against the end face 4a of the rotor 4. The flange base 12a extends a predetermined length in the axial direction from the end face 4a and has a substantially constant outer diameter. The amount of protrusion of the flange 12 decreases with increasing distance from the flange base 12a in the axial direction.

[0016] As shown in Figure 1, the outer peripheral edge of the flange base 12a that protrudes radially outward from the shaft hole 6 and protrudes outward most from the flange 12 forms a machined portion 13 for adjusting imbalance of the rotor 4. One or more balance adjustment holes 13a are formed in the machined portion 13 from its outer peripheral end surface toward the inside in the radial direction of the rotor shaft 8. The balance adjustment holes 13a are formed by drilling holes in the machined portion 13 as needed during a balance adjustment process in the manufacture of the motor 2.

[0017] 1 and 2, the fastening portion 14 protrudes in the axial direction from the end face 4b side of the rotor 4 of the rotor shaft 8. The fastening portion 14 has a base portion 14a extending a predetermined length in the axial direction from the end face 4b, and an externally threaded portion 14b extending a predetermined length from the base portion 14a along the axial direction away from the end face 4b. The externally threaded portion 14b has an external thread 15 on its outer circumferential surface that screws into a nut 16. The base portion 14a is formed with a larger diameter than the externally threaded portion 14b.

[0018] The nut 16 is fastened to the male thread portion 14b of the fastening portion 14 to secure the rotor 4 to the rotor shaft 8. The nut 16 includes a nut base portion 16a that corresponds to the base portion 14a, extends a predetermined length along the axial direction, and is close to the end face 4b, and a female thread portion 16b that corresponds to the male thread portion 14b. The nut 16 is attached, for example, between the nut base portion 16a and the end face 4b of the rotor 4 via a washer (not shown).

[0019] 1 and 2, the nut base 16a is formed to protrude radially outward from the shaft hole 6 by a predetermined amount and has a larger diameter than the female thread portion 16b. The inner peripheral surface of the nut base 16a is close enough to the outer peripheral surface of the base portion 14a of the fastening portion 14 so as not to come into contact with it. The inner peripheral surface of the female thread portion 16b has a female thread 17 that screws into the male thread 15 of the male thread portion 14b.

[0020] 1 and 2, the outer peripheral edge portion of the nut 16 that protrudes radially outward from the shaft hole 6 of the nut base 16a and protrudes outward most from the nut 16 forms a machined portion 19 for adjusting imbalance of the rotor 4. One or more balance adjustment holes 19a are formed in the machined portion 19 from its outer peripheral end surface toward the inside in the radial direction of the rotor shaft 8. The balance adjustment holes 19a are formed by drilling as necessary in the balance adjustment process during the manufacture of the motor 2.

[0021] Motor 2 has workpieces 13 and 19, which are provided with balance adjustment holes 13a and 19a, making it possible to correct imbalance in rotor 4 and adjust balance. Furthermore, workpiece 13 and workpiece 19 do not axially overlap with the engagement portion of male thread 15 and female thread 17, so drilling holes in workpieces 13 and 19 does not have a significant effect on the contact state between rotor 4 and rotor shaft 8. Furthermore, since there is no need to attach a separate part to rotor shaft 8 for balance adjustment, extension of the axial length of rotor shaft 8 is suppressed.

[0022] Furthermore, the processed portions 13, 19 are formed by the rotor shaft 8 and the fastening portion 14, and do not shield most of the surface area of ​​the end faces 4a, 4b of the rotor 4. This allows the coolant to be smoothly discharged from the rotor shaft 8 through the coolant flow path 7 and the end faces 4b, 4b of the rotor 4. As a result, cooling of the rotor 4 and the coil ends of the stator is not hindered. Furthermore, the processed portions 13, 19 have a predetermined length along the axial direction to allow for hole processing, and protrude a predetermined amount radially outward. This improves the rigidity and strength of the rotor shaft 8.

[0023] It is noted that only one of the workpiece portions 13, 19 and the balance adjustment holes 13a, 19a may be provided. Alternatively, only the workpiece portions 13, 19 may be provided without the balance adjustment holes 13a, 19a. Furthermore, the manner in which the holes are formed in the workpiece portions 13, 19 is not limited to the manner shown in Figures 1 and 2, and various other manners are possible. The balance adjustment holes 13a, 19a may be formed from the axially outer side toward the axially inner side.

[0024] For example, as shown in Fig. 3(a), at least a part of the nut base 16a of the nut 16 may be formed as a flange-like base 20 that protrudes significantly radially outward, and the outer peripheral edge of the flange-like base 20 may be used as the processed portion 21. In the processed portion 21, an adjustment hole 21a may be formed from the axially outer side toward the inside, as shown in Fig. 3(a), or an adjustment hole 21b may be formed from the radially outer side toward the inside, as shown in Fig. 3(b).

[0025] 3(a) and 3(b), the outer peripheral edge of the flange-shaped base 20, which is spaced far outward in the radial direction from the rotor shaft 8, is the processed portion 21. This makes it possible to suppress the effect of the balancing process on the fastening state between the rotor 4 and the rotor shaft 8, thereby enabling balance adjustment. Also, as shown in FIGS. 3(a) and 3(b), the portion of the flange-shaped base 20 extending from the outer edge of the female thread portion 16b to the processed portion 21 may be thin-walled as needed to reduce the mass of the flange-shaped base 20. [Explanation of symbols]

[0026] 2 motor, 4 rotor, 6 shaft hole, 7 refrigerant flow path, 8 rotor shaft, 10 main body, 12 flange, 12a flange base, 13 processed part, 13a balance adjustment hole, 14 fastening part, 14a base, 14b male thread part, 15 male thread, 16 nut, 16a nut base, 16b female thread part, 17 female thread, 19 processed part, 19a balance adjustment hole, 20 flange-shaped base, 21 processed part, 21a balance adjustment hole

Claims

[Claim 1] A motor, a rotor shaft having a flange at one end and a nut at the other end; a rotor attached to the rotor shaft by the flange and the nut; Equipped with a motor having a balance adjustment processing portion and a balance adjustment hole on the outer peripheral edge portion of at least one of the flange and the nut, the processing portion extending a predetermined length along the axial direction of the rotor shaft and projecting radially outward from the rotor shaft.

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