WO2019213897A1

WO2019213897A1 - Rotor shaft and machining method therefor

Info

Publication number: WO2019213897A1
Application number: PCT/CN2018/086336
Authority: WO
Inventors: 张晓慧; 杨建文; 徐启喆
Original assignee: 西门子股份公司
Priority date: 2018-05-10
Filing date: 2018-05-10
Publication date: 2019-11-14

Abstract

Provided in the present invention is a rotor shaft, primarily comprising a rotor shaft body and limiting parts, the limiting parts being provided on the outer surface of the rotor shaft body, and protruding from said outer surface in the radial direction of the rotor shaft body. Magnetic steel accommodating spaces are formed between every two neighboring limiting parts. The limiting parts are able to limit displacement of magnetic steel on the surface of the rotor shaft, improving the efficiency and accuracy of magnetic steel installation. Additionally provided in the present invention is a rotor shaft machining method.

Description

Rotor shaft and processing method thereof

Technical field

The present invention relates to a rotor shaft suitable for use in an electric machine and a method of processing the same.

Background technique

At present, the motor rotor shaft magnetic steel generally adopts a surface-mounted structure, usually a layer of glue is first applied on the surface of the rotor shaft, and then the magnetic steel is pasted on the surface of the rotor shaft coated with glue. If there is no limit assisting device, it is difficult to keep the magnetic steel fixed in the correct position. If the rotor with poor precision of the pasting position is applied to the motor, it will seriously affect the motor performance of the motor where the rotor is located. One conventional method is to attach an auxiliary mounting device, such as a plastic cage, to the surface of the rotor shaft. The accuracy and quality of the plastic cage directly affect the positioning accuracy of the magnetic steel. However, there are many technical problems in fixing the magnetic steel by means of plastic cages, for example, the plastic cage mold is very complicated, the manufacturing cost is high, the mold is deformed due to heat, and the precision is lowered, and the mold is only suitable for a rotor shaft of a specific size. The versatility is poor.

Summary of the invention

According to an aspect of the invention, a rotor shaft is provided, wherein the rotor shaft includes: a rotor shaft body; and a limiting portion disposed on an outer surface of the rotor shaft body, and The limiting portion protrudes from the outer surface along a radial direction of the rotor shaft body, and a magnetic steel receiving space is formed between the adjacent two limiting portions. The limiting portion can limit the displacement of the magnetic steel on the surface of the rotor shaft, and improve the installation efficiency and precision of the magnetic steel.

In one embodiment, the limiting portions are evenly distributed around the circumferential direction of the rotor shaft. The magnetic steel can be evenly arranged on the circumference of the rotor shaft, which ensures the accuracy of the magnetic steel installation.

In one embodiment, the rotor shaft body is divided into at least two shaft segments along its axial direction, and each of the shaft segments is circumferentially disposed with a set of the limiting portions, and belongs to different shaft segments. The two adjacent ones of the limiting portions are axially offset from each other such that the rotor shaft forms a slant pole. By means of the limiting portion, the magnetic steel can be positioned on the rotor shaft and the magnetic steel is dislocated, that is, the oblique pole function, and the auxiliary structure is not required, so that the overall structure of the motor is more compact.

In one embodiment, the limit portions in the same group of shaft segments are parallel to each other and have the same distance, and the number of the limit portions is the same for each group. A magnetic steel accommodating space having the same area is left between the adjacent two limiting portions, and the same type of magnetic steel can be used for assembly.

In an embodiment, the limiting portion is a rib extending in an axial direction of the rotor shaft. The length of the ribs corresponds to the length of the magnetic steel, which can completely isolate and fix the adjacent magnetic steel, and limit the displacement of the magnetic steel on the surface of the rotor shaft.

In one embodiment, the ridge includes two snap portions and one base, one end of the base is connected to an outer surface of the rotor shaft body, and the other end is connected to a respective end of the two buckle portions. . The buckle portion of the rib is pressed against the shoulder of the magnetic steel to fix the magnetic steel on the surface of the rotor shaft, so that the magnetic steel is assembled firmly, safe and reliable.

In one embodiment, each of the limiting portions is formed by at least two projections that are arranged along an axial direction of the rotor shaft. The processing material used for manufacturing the stopper can be saved, the cost can be reduced, and the processing time can be shortened.

In one embodiment, the rotor shaft body is the optical axis of the rotor shaft. The invention can realize the positioning of the magnetic steel on the optical axis and can realize the oblique pole function, without setting the iron core outside the rotor shaft to locate the magnetic steel, without using the protrusion on the rotor core to fix the position of the magnetic steel, and without passing through the iron core The process hole realizes the magnetic steel misalignment or the oblique pole during the assembly process. The development and assembly of the rotor core is eliminated, which simplifies the motor structure and assembly, making the entire motor product development and production more efficient.

According to another aspect of the present invention, a rotor shaft machining method is provided, wherein the machining method comprises the steps of: S1: providing a rotor shaft body; and, S2: using an additive manufacturing method according to a preset parameter a limiting portion is added to the rotor shaft body, wherein the limiting portion is disposed on an outer surface of the rotor shaft body, and the limiting portion is from the outer side in a radial direction of the rotor shaft body The surface is convex, and a magnetic steel accommodating space is formed between the adjacent two limiting portions. The rotor shaft is processed by the method of additive manufacturing, the material utilization rate is high, and the high machining precision can be realized; and the structural parameters of the rotor shaft and the limit portion can be adjusted according to actual conditions, for the angle of the magnetic steel misalignment, There is no limit to the number of segments of the rotor shaft shaft segment and the diameter of the rotor shaft.

In one embodiment, the additive manufacturing method is one or more of 3D printing, welding, overlay welding, arc additive manufacturing, and laser additive manufacturing. The processing method is flexible and convenient, the operation is simple, the processing precision is high, the time is short, and the efficiency is high.

DRAWINGS

The accompanying drawings are included to provide a further understanding of the embodiments of the invention In the figure:

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of one embodiment of a rotor shaft and magnetic steel mating in accordance with the present invention.

2 is a schematic illustration of one embodiment of a rotor shaft in accordance with the present invention.

3 is a schematic illustration of another embodiment of a rotor shaft in accordance with the present invention.

4 is a schematic cross-sectional view of yet another embodiment of a rotor shaft in accordance with the present invention.

Description of the reference signs:

10 rotor shaft

12 magnetic steel accommodation space

20 limit department

211,212 buckle

22 base

30 magnetic steel

detailed description

Embodiments of the present invention will now be described in detail with reference to the drawings. Reference will now be made in detail to the preferred embodiments embodiments of the invention Wherever possible, the same reference numerals reference Further, although the terms used in the present invention are selected from well-known public terms, some of the terms mentioned in the specification of the present invention may be selected by the applicant according to his or her judgment, and the detailed meaning thereof is herein. The description of the relevant part of the description. Furthermore, it is intended that the present invention be understood not only by the actual terms used, but also by the meaning of each term.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of one embodiment of a rotor shaft and magnetic steel mating in accordance with the present invention. For example, the magnetic steel 30 has a tile shape, and the radial cross section of the magnetic steel 30 may be surrounded by inner and outer arcs having different curvatures. In this embodiment, the arc of the inner arc of the magnet 30 is the same as the arc of the outer surface of the rotor shaft, so that the magnet 30 is closely attached to the outer surface of the rotor shaft body 10, and is uniformly attached to the circumferential surface of the rotor shaft to Meet the electromagnetic design requirements of the motor.

A specific embodiment of the rotor shaft provided by the present invention will be described below with reference to Figs. 2, 3 and 4. The rotor shaft mainly includes a rotor shaft body 10 and a limiting portion 20, and the limiting portion 20 is disposed on an outer surface of the rotor shaft body 10, and the limiting portion 20 protrudes from the outer surface in a radial direction of the rotor shaft body 10, That is, the outer surface of the rotor shaft body 10 has a plurality of outwardly protruding limiting portions 20, and a magnetic steel receiving space 12 is formed between the adjacent two limiting portions 20, and the magnetic steel 30 can be placed one by one. The magnetic steel accommodates 12 spaces. The limiting portion 20 can fix the magnetic steel 30 in the magnetic steel accommodating space 12, restrict displacement of the magnetic steel 30 on the surface of the rotor shaft, and improve mounting efficiency and accuracy.

As an example, the limiting portions 20 are evenly distributed around the circumferential direction of the rotor shaft, so that the magnetic steel 30 can be evenly arranged on the circumference of the rotor shaft, effectively ensuring the accuracy of the mounting of the magnetic steel 30. In order to reduce the magnetic density harmonics, the motor can be designed with a diagonal pole. For example, the design is a segmented oblique pole. The rotor shaft is first divided into at least two shaft segments along its axial direction, and then each oblique pole angle is determined according to the number of shaft segments, and the magnetic steel 30 is staggered and installed at a certain oblique angle. The rotor shaft can be set as a double-segment oblique pole, as shown in Figure 1. The rotor shaft can also be divided into three-section, four-section or five-section shaft sections and a diagonal pole is set, and a set of limits is circumferentially arranged on each shaft section. The position portion 20 and the adjacent two limit portions 20 belonging to different shaft segments are axially offset from each other by a certain distance so that the rotor shaft forms a slant pole. By means of the staggered positioning portion 20, the magnetic steel can be positioned on the rotor shaft and the magnetic steel misalignment or the oblique pole function can be realized, and the auxiliary structure is not required, so that the overall structure of the motor is more compact. The number of the limiting portions 20 corresponds to the number of magnets 30 to be mounted on the surface of the rotor shaft body 10. For example, in one embodiment, the rotor shaft surface needs to be affixed with 8 pieces of magnetic steel, so that 8 limit portions 20 can be correspondingly distributed uniformly around the center of the rotor shaft; in another embodiment, if the rotor shaft adopts double-section oblique In the design of the pole, two sets of limiting portions 30 can be arranged, and the limiting portions 20 in the same set of axial segments are parallel to each other and have the same distance, and the number of the limiting portions 20 distributed in each axial segment is the same. It can be assembled with the same type of magnetic steel. The number of magnets 30 to be attached to the rotor shaft can be any number, and the rotor shaft provided by the present invention can be satisfied.

The present invention is particularly suitable for miniaturizing motors because the need for a conventional rotor core can be eliminated. In this application, the rotor shaft body 10 described above is an optical axis. Due to the weight reduction of the rotor in the miniaturized motor, the above-mentioned limiting portion 20 directly disposed on the optical axis is sufficient to fix the magnetic steel, thereby eliminating the optical axis. A conventional rotor core (the mounting hole of the rotor core or the projection on the core is usually used to fix the position of the magnetic steel), which simplifies the assembly structure and reduces the cost.

Further, the present invention can realize the oblique pole function without using the rotor core, and does not need to use the protrusion on the rotor core to fix the position of the magnetic steel, and does not need to realize the magnetic steel misalignment during the assembly process through the process hole of the rotor core. Oblique pole. The development and assembly of the rotor core is eliminated, which simplifies the motor structure and assembly, making the entire motor product development and production more efficient.

In one embodiment, as shown in FIG. 2, the limiting portion 20 is a rib extending in the axial direction of the rotor shaft, and the length of the rib can correspond to the length of the magnetic steel to completely adjacent the magnetic steel. Isolation and fixing limit the displacement of the magnetic steel on the surface of the rotor shaft. In order to better fix the magnetic steel, the structure of the ribs can also be optimized. For example, FIG. 4 is a schematic cross-sectional view of a rotor shaft embodiment provided by the present invention, wherein the rib shape is substantially T-shaped, and specifically, the rib includes two

snap portions

211, 212 and a base portion 22, the base portion One end is connected to the outer surface of the rotor shaft body 10, and the other end is connected to the respective ends of the two

fastening portions

211, 212. The locking

portions

211, 212 of the protruding strip can be pressed against the shoulder of the magnetic steel to fix the magnetic steel on the surface of the rotor shaft. The magnetic steel is assembled firmly, safely and reliably. Or in another embodiment, in order to reduce the cost and shorten the processing time, the limiting portion 20 may also be disposed as continuous bumps arranged along the axial direction of the rotor shaft, as shown in FIG. The portion 20 is composed of two protrusions, or may be composed of two or more protrusions distributed in the axial direction, which can save the processing material used for manufacturing the stopper portion 20.

The rotor shaft machining method mainly includes steps S1 and S2. In step S1, a rotor shaft body 10 is provided. In step S2, a limiting portion 20 is added to the rotor shaft body 10 according to a preset parameter, and the limiting portion 20 is disposed on the rotor shaft body 10. On the outer surface, the limiting portion 20 protrudes from the outer surface in the radial direction of the rotor shaft body 10, and a magnetic steel accommodating space 12 is formed between the adjacent two limiting portions 20. The additive manufacturing method may be, for example, one or more of 3D printing, welding, overlay welding, arc additive manufacturing, and laser additive manufacturing. The rotor shaft is processed by the method of additive manufacturing, the processing method is flexible and convenient, the operation is simple, the processing precision is high, the time is short, and the material utilization rate is high; the manufacturing parameters can be adjusted according to the actual situation, and the angle of the limit portion 20 is misaligned, There is no limit to the number of segments of the shaft segment and the diameter of the rotor shaft. The additive manufacturing method is a technique of manufacturing solid parts by gradually adding materials. Compared with the conventional material removal, cutting and other processing techniques, the additive manufacturing method does not require traditional tools and fixtures and multiple processing steps in one device. The parts can be manufactured in any complicated shape quickly and precisely, and the machining process is greatly reduced, and the machining cycle is shortened. In combination with the structural dimensions of different types of rotor shafts, the built-in parameters of the 3D printer can be adjusted, and the limit portion 20 is printed on the rotor shaft body 10 by using a 3D printer, which has high printing precision and can be difficult to be completed in a conventional production process. . In the process of printing production using 3D printer, the utilization rate of printing materials is also very high, no residual materials and wastes are generated, and cost is saved. The 3D printing process is simple, and the prototype of the product can be quickly designed, and the parameters can be quickly verified and completed. Changes. In addition to 3D printing, a raised limit portion 20 may be provided on the surface of the rotor shaft by other additive manufacturing methods. For example, the metal strip may be welded to the surface of the rotor shaft by welding.

It is apparent to those skilled in the art that various modifications and variations can be made in the above-described embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, it is intended that the present invention cover the modifications and modifications of the invention

Claims

A rotor shaft, wherein the rotor shaft comprises:

Rotor shaft body (10);

a limiting portion (20), the limiting portion (20) is disposed on an outer surface of the rotor shaft body (10), and a diameter of the limiting portion (20) along the rotor shaft body (10) A direction is protruded from the outer surface, and a magnetic steel accommodating space (12) is formed between the adjacent two limiting portions (20).
The rotor shaft according to claim 1, wherein said limiting portions (20) are evenly distributed around a circumferential direction of said rotor shaft.
A rotor shaft according to claim 2, wherein said rotor shaft body (10) is divided into at least two shaft segments along its axial direction, each of said shaft segments being circumferentially disposed with a set of said limits The position portion (20), and the adjacent two of the limit portions (20) belonging to different shaft segments are axially offset from each other such that the rotor shaft forms a slant pole.
The rotor shaft according to claim 3, wherein the limiting portions (20) in the same set of shaft segments are parallel to each other and spaced apart from each other, and each of the sets of the limiting portions (20) The number is the same.
A rotor shaft according to claim 1, wherein said limiting portion (20) is a rib extending in the axial direction of the rotor shaft.
A rotor shaft according to claim 5, wherein said rib includes two snap portions (211, 212) and a base portion (22), one end of said base portion being coupled to said rotor shaft body (20) The other end connects the respective ends of the two latching portions (211, 212).
A rotor shaft according to claim 1, wherein each of said limiting portions (20) is constituted by at least two projections which are arranged in the axial direction of said rotor shaft .
A rotor shaft according to claim 1, wherein said rotor shaft body (10) is an optical axis of a rotor shaft.
A rotor shaft machining method, wherein the machining method comprises the following steps:

S1: providing a rotor shaft body (10); and,

S2: adding a limiting portion (20) to the rotor shaft body (10) according to a preset parameter, wherein the limiting portion (20) is disposed on the rotor shaft body (10) On the outer surface, and the limiting portion (20) protrudes from the outer surface in a radial direction of the rotor shaft body (10), between the two adjacent limiting portions (20) A magnetic steel accommodation space (12) is formed.
The rotor shaft machining method according to claim 9, wherein the additive manufacturing method is one or more of 3D printing, welding, surfacing, arc additive manufacturing, and laser additive manufacturing.