US-12620855-B2 - Rotor manufacturing method, and rotor

US12620855B2US 12620855 B2US12620855 B2US 12620855B2US-12620855-B2

Abstract

A sleeve of a rotor includes a first sleeve layer and a second sleeve layer. The first sleeve layer is arranged on the most radially inward and fitted to an outer peripheral portion of a rotor body. The second sleeve layer is arranged radially outward of the first sleeve layer and fitted thereto. In a fitting step, the outer peripheral portion of the rotor body is pressed and fitted into a first sleeve layer having a first inner diameter that is smaller than an outer diameter of the outer peripheral portion. Then, a first outer peripheral portion of the first sleeve layer fitted to the outer peripheral portion of the rotor body is pressed into a second sleeve layer having a second inner diameter that is smaller than a first outer diameter of the first sleeve layer, and fitted to the second sleeve layer.

Inventors

Yuki Abe
Yuki Hasegawa
Masatoshi NAGASHIMA

Assignees

HONDA MOTOR CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20240220
Priority Date: 20230303

Claims (3)

1 . A method of manufacturing a rotor, the rotor including: a rotor core; a plurality of permanent magnets provided in an outer peripheral portion of the rotor core and arranged in a circumferential direction of the rotor core; and a sleeve having a cylindrical shape and surrounding an outer peripheral portion of a rotor body that includes the rotor core and the plurality of permanent magnets, the sleeve being fitted to the rotor body and configured to apply a pressurizing force directed radially inward to the plurality of permanent magnets, wherein the sleeve includes a plurality of at least two sleeve layers laminated radially, the plurality of sleeve layers includes: a first sleeve layer disposed most radially inward of the sleeve and fitted to the outer peripheral portion of the rotor body; and a second sleeve layer disposed radially outward of the first sleeve layer and fitted to the first sleeve layer, the method comprising: pressing and fitting the outer peripheral portion of the rotor body, into the first sleeve layer having a first inner diameter that is smaller than an outer diameter of the outer peripheral portion of the rotor body; and pressing and fitting a first outer peripheral portion of the first sleeve layer fitted to the outer peripheral portion of the rotor body, into the second sleeve layer having a second inner diameter that is smaller than a first outer diameter of the first sleeve layer.
2 . The method of manufacturing the rotor according to claim 1 , wherein the plurality of sleeve layers include a third sleeve layer disposed radially outward of the second sleeve layer and fitted to a second outer peripheral portion of the second sleeve layer, and the method further comprises pressing and fitting the second outer peripheral portion of the second sleeve layer fitted to the first sleeve layer, into the third sleeve layer having a third inner diameter that is smaller than a second outer diameter of the second sleeve layer.
3 . The method of manufacturing the rotor according to claim 1 , wherein the plurality of sleeve layers are formed of a carbon fiber reinforced material.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2023-032866 filed on Mar. 3, 2023, the contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a rotor manufacturing method and a rotor. Description of the Related Art JP 7049285 B2 discloses a rotor of a rotating electric machine. The rotor is provided with permanent magnets fixed to an outer peripheral surface of a rotor core, and a cylindrical sleeve which applies a pressurizing force to the rotor core by covering an outer peripheral portion of the rotor core. The gaps between the sleeve and the magnets are filled with resin, and the resin is solidified. When the rotor rotates, the sleeve and the resin prevent the permanent magnets from moving radially outward due to centrifugal force. SUMMARY OF THE INVENTION In general, in a rotor as disclosed in JP 7049285 B2, it is required to prevent the movement of the permanent magnets due to the centrifugal force only by the sleeve, and it is also required to make the sleeve thinner. However, it is difficult to achieve both the satisfactory pressurizing force applied to the rotor core by the sleeve and the satisfactory thinness of the sleeve. Further, when the sleeve of the single layer structure is attached to the outer peripheral portion of the rotor core, a circumferential stress acting in the circumferential direction of the sleeve is distributed so as to become smaller from the inner peripheral side toward the outer peripheral side. Therefore, the sleeve cannot efficiently apply the pressurizing force to the outer peripheral portion of the rotor core. According to an aspect of the present invention, a method of manufacturing a rotor is provided. The rotor includes a rotor core, a plurality of permanent magnets provided in an outer peripheral portion of the rotor core and arranged in a circumferential direction of the rotor core, and a sleeve having a cylindrical shape and surrounding an outer peripheral portion of a rotor body that includes the rotor core and the plurality of permanent magnets, the sleeve being fitted to the rotor body and configured to apply a pressurizing force directed radially inward to the plurality of permanent magnets, wherein the sleeve includes a plurality of at least two sleeve layers laminated radially, the plurality of sleeve layers includes a first sleeve layer disposed most radially inward of the sleeve and fitted to the outer peripheral portion of the rotor body, and a second sleeve layer disposed radially outward of the first sleeve layer and fitted to the first sleeve layer. The method includes a first fitting step of pressing and fitting the outer peripheral portion of the rotor body, into the first sleeve layer having a first inner diameter that is smaller than an outer diameter of the outer peripheral portion of the rotor body, and a second fitting step of pressing and fitting a first outer peripheral portion of the first sleeve layer fitted to the outer peripheral portion of the rotor body, into the second sleeve layer having a second inner diameter that is smaller than a first outer diameter of the first sleeve layer. According to the present invention, by pressing and fitting the first sleeve layer fitted to the outer peripheral portion of the rotor body, into the second sleeve layer having the second inner diameter that is smaller than the first outer diameter of the first sleeve layer, the difference between the circumferential stress in the second sleeve layer and the circumferential stress in the first sleeve layer can be suppressed. In this way, as compared with the structure in which the pressurizing force is applied to the rotor body by the sleeve of the single layer structure, the pressurizing force applied radially inward by the second sleeve layer disposed radially outward can be efficiently increased, and therefore the thickness of the sleeve in the radial direction can be reduced. Alternatively, compared with a sleeve of a single layer structure having the same thickness, the allowable number of rotations when the rotor rotates can be improved. The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which a preferred embodiment of the present invention is shown by way of illustrative example. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall plan view of a rotor according to an embodiment of the present invention; FIG. 2 is an enlarged cross-sectional view of a periphery of the sleeve in the rotor of FIG. 1; FIG. 3 is a diagram showing the overall configuration of a manufacturing apparatus for a rotor; FIG. 4A is an explanatory view showing a process up to a liquid introduction step in a first fitting step of attaching a first sleeve layer i