Multi-section staggered strip-shaped hole motor rotor sheath

Abstract

The invention discloses a multi-section staggered strip-shaped hole motor rotor sheath, which is suitable for an inner rotor permanent magnet motor, and has double effects of axial segmentation and radial segmentation in the aspect of inhibiting eddy current loss. The protective sleeve is assembled on the surface of a motor rotor in an interference fit mode, the protective sleeve is divided into m sections at equal intervals in the axial direction, and m is a positive integer; and strip-shaped holes with specific lengths and widths are uniformly distributed in each section. According to the invention, the eddy-current loss of the rotor sheath can be obviously reduced under the condition that the mechanical strength requirement of the sheath is met, so that the efficiency of the permanent magnet motor is improved. Compared with a traditional sheath structure, the motor rotor sheath structure with the multiple sections of staggered strip-shaped holes has the advantages that eddy current loss in the sheath can be remarkably reduced, and the efficiency of a motor is improved.

Description

Technical Field

[0001] The invention belongs to the field of permanent magnet motor design and manufacturing, and in particular relates to a multi-section staggered strip hole motor rotor sleeve. Background Art

[0002] The fractional slot concentrated winding permanent magnet motor is a type of motor that is becoming increasingly popular in modern motor design. It has the advantages of high power density, low torque pulsation, compact winding ends, and strong phase independence. Therefore, it has attracted much attention in the fields of aerospace, military equipment, transportation, and new energy vehicles. However, the fractional slot concentrated winding permanent magnet motor contains abundant magnetomotive force harmonics. These harmonics are not synchronized with the rotor rotation, which will induce large eddy current losses in conductors such as the rotor sleeve and permanent magnets. In addition, the rotor is difficult to dissipate heat, resulting in excessive temperature rise inside the motor, which seriously threatens the safe and reliable operation of the motor system. In addition, the increased loss makes it difficult to effectively improve the efficiency of the motor. The high-speed development of modern permanent magnet motors is a trend, which can further improve the power density of the motor, but also puts higher requirements on the mechanical strength and eddy current loss of the rotor. Therefore, suppressing the rotor eddy current loss of the fractional slot concentrated winding permanent magnet motor is of great practical significance for promoting the application of permanent magnet motors in high-speed occasions.

[0003] Many literature studies have shown that segmentation technology is one of the effective means to suppress eddy current losses. Its principle is to reduce the eddy current flow path by dividing the sheath or permanent magnet into multiple small segments, thereby reducing the eddy current loss. The eddy current loss of each small segment is significantly smaller than the eddy current loss of the entire permanent magnet. On the one hand, segmentation technology is used to reduce the eddy current loss on the permanent magnet or sheath. On the other hand, the sheath plays a role in protecting the permanent magnet, and the segmentation of the sheath will significantly reduce the mechanical strength of the entire rotor, especially at high speeds. The more segments there are, the more obvious the eddy current loss suppression effect is, but at the same time it is inevitable to increase the manufacturing complexity and cost, so it needs to be optimized according to the specific application and performance requirements. Under the premise of meeting the requirements of the mechanical strength of the sheath, it is of great practical significance to reduce the eddy current loss of the rotor sheath and improve the efficiency and power density of the permanent magnet motor. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a multi-segment staggered strip-hole motor rotor sleeve, which has both axial segmentation and radial segmentation effects in suppressing eddy current losses.

[0005] Technical solution: The multi-segment staggered strip-hole motor rotor sleeve of the present invention is suitable for inner rotor permanent magnet motors and is assembled on the surface of the motor rotor by interference fit. The sleeve is equidistantly divided into m sections along the axial direction, where m is a positive integer; each section is evenly distributed with strip holes of specific length and width.

[0006] Furthermore, the central angle of the center lines of two adjacent holes in the same section in the radial direction is θ 0 , the θ 0 The first-order magnetomotive force tooth harmonic order v of the inner rotor permanent magnet motor slot Related, the first-order tooth harmonic order is:

[0007] v slot =|N s -p r |

[0008] Among them, N s and p r are the number of slots in the motor and the number of pole pairs of the rotor permanent magnet, respectively. 0 =360° / v slot .

[0009] Furthermore, the length L of the strip hole m Axial length L of the sheath ef It is related to the number of axially divided sections m, and the relationship is:

[0010]

[0011] The strip hole length L m The range is 8 to 12 mm, so that the number of axially divided sections m is a positive integer.

[0012] Furthermore, the arc θ of the strip hole m Angle θ with the center of the circle 0 The relationship is proportional, that is:

[0013] θ m =k m θ 0

[0014] Among them, the proportionality coefficient k m Take 2% to 5%.

[0015] Furthermore, the strip holes located in the first section and the strip holes located in the second section have an overall misalignment angle θ s The overall misalignment angle between the strip holes in the first section and the strip holes in the third section is 2θ s , and so on, the overall misalignment angle between the strip hole located in the first section and the strip hole located in the mth section is (m-1)θ s .

[0016] Furthermore, the overall misalignment angle θ s :

[0017] θ s =2π / S eq

[0018] Among them, S eq is the equivalent segment number of the sheath, the equivalent segment number S eq The order v of the first-order magnetomotive force tooth harmonic slot Related, the relationship is S eq =2v slot .

[0019] Furthermore, the inner rotor permanent magnet motor comprises permanent magnets, a rotor core and a rotating shaft; the permanent magnets are evenly adhered to the outer surface of the rotor core along the circumference, and the rotor core is sleeved on the rotating shaft.

[0020] Furthermore, the sheath is made of high-strength stainless steel material.

[0021] Furthermore, the permanent magnet includes a surface-mounted structure, a Halbach array structure and a built-in structure.

[0022] Furthermore, the magnetization method of the permanent magnet is determined according to the specific structure, and the magnetization methods include radial magnetization and parallel magnetization.

[0023] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0024] (1) The rotor sleeve proposed in the present invention not only retains its ability to protect the rotor, but also can limit the eddy current path through the strip holes opened, thereby reducing its own eddy current loss. In addition, the strip holes are opened according to the calculation method of the present invention, which can minimize its own eddy current loss. In the process of opening the strip holes of the present invention, the distribution of the strip holes is not random, but according to specific rules and the main harmonic orders of eddy current losses generated in the motor, the equivalent segmentation method is adopted to integrate the axial segmentation and radial segmentation technologies to reduce the eddy current loss on the sleeve, thereby improving the overall efficiency of the motor.

[0025] (2) While meeting the requirements of the mechanical strength of the sheath, the eddy current loss of the rotor sheath can be significantly reduced, thereby improving the efficiency of the permanent magnet motor. Compared with the traditional sheath structure, the multi-stage staggered strip hole motor rotor sheath structure of the present invention can significantly reduce the eddy current loss in the sheath, thereby improving the efficiency of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a multi-section staggered strip hole sheath and a planar development diagram of the present invention;

[0027] Figure 2 This is a schematic diagram of the angle between two adjacent shaped holes in the same section of the present invention;

[0028] Figure 3 It is the dimension marking diagram of the strip-shaped hole of the present invention;

[0029] Figure 4 It is a schematic diagram and annotated diagram of the overall dislocation of strip holes in different sections of the present invention;

[0030] Figure 5 The eddy current loss of the conventional sheath permanent magnet motor and the multi-stage staggered strip hole sheath permanent magnet motor of the present invention;

[0031] Figure 6 It is a schematic diagram of a permanent magnet motor rotor, wherein 1 is the multi-section staggered strip hole sleeve proposed by the present invention, 2 is the strip holes opened on the sleeve, 3 is the permanent magnet, 4 is the rotor core, and 5 is the motor shaft. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0033] Reference Figure 1 and Figure 6 A multi-segment staggered strip hole motor rotor sleeve comprises a sleeve 1 and strip holes 2 on its surface. The thickness of the sleeve is 1 mm and the sleeve is sleeved on the surface of a permanent magnet 3 by interference fit.

[0034] The sheath 1 is provided with strip-shaped holes 2 according to a specific rule, and the specific rule for providing the strip-shaped holes is:

[0035] Reference Figure 1 The sheath 1 is divided into m sections equidistantly along the axial direction, wherein m is a positive integer.

[0036] Reference Figure 1 In this embodiment, m is 6, and the length of the strip hole is L m The axial length of the sheath is L ef It is closely related to the number of axially divided sections m, and the specific relationship between them is m = L ef / L m , characterized in that: the strip hole length L m It is selected within the range of 8 to 12 mm so that the number of axially divided sections m is a positive integer.

[0037] Reference Figure 1 Each section of the sheath 1 is evenly distributed with strip holes 2 of specific length and width.

[0038] Reference Figure 2The central angle of the center lines of the two adjacent holes 2 in the same section in the radial direction is θ 0 , characterized in that: the θ 0 The first-order magnetomotive force tooth harmonic order v of the motor slot It is characterized by: the first-order tooth harmonic order v slot =|N s -p r |, the N s and p r are the number of slots in the motor and the number of pole pairs of the rotor permanent magnet, respectively. 0 =360° / v slot ;

[0039] Reference Figure 3 , the arc angle of the strip hole 2 is θ m With θ 0 is proportional, that is, θ m =k m θ 0 , characterized by: the proportionality coefficient k m Take 2% to 5%.

[0040] Reference Figure 4 The overall misalignment angle between the strip holes in the first section and the strip holes in the second section of the sheath 1 is θ s The overall misalignment angle between the strip holes in the first section and the strip holes in the third section is 2θ s , and so on, the overall misalignment angle between the strip hole located in the first section and the strip hole located in the mth section is (m-1)θ s , characterized in that: the misalignment angle θ s =2π / S eq , S eq is the equivalent segment number of the sheath, characterized in that: the equivalent segment number S eq The order v of the first-order magnetomotive force tooth harmonic slot Related, the relationship is S eq =2v slot .

[0041] The sleeve is suitable for an inner rotor permanent magnet motor and is assembled on the surface of the motor rotor by interference fit to enhance the mechanical strength of the entire rotor.

[0042] The motor rotor comprises a permanent magnet, a rotor core and a rotating shaft; the permanent magnet is evenly adhered to the outer surface of the rotor core along the circumference, and the rotor core is sleeved on the rotating shaft.

[0043] The sheath is made of high-strength stainless steel material.

[0044] The permanent magnet may be a surface mounted structure, a Halbach array structure, or a built-in structure; the magnetization method of the permanent magnet is determined according to the specific structure, and the magnetization methods include radial magnetization and parallel magnetization.

[0045] Reference Figure 5 , which is the eddy current loss of the traditional sheath motor and the multi-stage staggered bar hole motor of the present invention at different speeds. As shown in the figure, the rotor sheath structure of the multi-stage staggered bar hole motor of the present invention can greatly reduce the eddy current loss of the motor.

[0046] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of application of the present invention should still fall within the scope of the present invention.

Claims

1. A multi-stage staggered strip hole motor rotor sleeve, suitable for inner rotor permanent magnet motor, assembled on the motor rotor surface by interference fit, characterized in that: The sheath is divided into m sections equidistantly along the axial direction, where m is a positive integer; strip holes of specific length and width are evenly distributed in each section.

2. The multi-stage staggered strip hole motor rotor sleeve according to claim 1, characterized in that: The radial center angle of the center lines of two adjacent holes in the same section is θ0, which is related to the first-order magnetomotive force tooth harmonic order v of the inner rotor permanent magnet motor. slot Related, the first-order tooth harmonic order is: v slot =|N s -p r | Among them, N s and p r are the number of slots in the motor and the number of pole pairs of the rotor permanent magnet, respectively. The θ0 = 360° / v slot .

3. The multi-stage staggered strip hole motor rotor sleeve according to claim 1, characterized in that: The length L of the strip hole m Axial length L of the sheath ef It is related to the number of axially divided sections m, and the relationship is: The strip hole length L m The range is 8 to 12 mm, so that the number of axially divided sections m is a positive integer.

4. The multi-stage staggered strip-hole motor rotor sleeve according to claim 2, characterized in that: The arc θ of the strip hole m It is proportional to the central angle θ0, that is: i m =k m θ0 Among them, the proportionality coefficient k m Take 2% to 5%.

5. The multi-stage staggered strip-hole motor rotor sleeve according to claim 1, characterized in that: The strip holes located in the first section and the strip holes located in the second section have an overall misalignment angle θ s The overall misalignment angle between the strip holes in the first section and the strip holes in the third section is 2θ s , and so on, the overall misalignment angle between the strip hole located in the first section and the strip hole located in the mth section is (m-1)θ s .

6. The multi-stage staggered strip-hole motor rotor sleeve according to claim 5, characterized in that: The overall misalignment angle θ s : i s =2π / S eq Among them, S eq is the equivalent segment number of the sheath, the equivalent segment number S eq The order v of the first-order magnetomotive force tooth harmonic slot Related, the relationship is S eq =2v slot .

7. The multi-stage staggered strip-hole motor rotor sleeve according to claim 1, characterized in that: The inner rotor permanent magnet motor comprises a permanent magnet, a rotor core and a rotating shaft; the permanent magnet is evenly adhered to the outer surface of the rotor core along the circumference, and the rotor core is sleeved on the rotating shaft.

8. The multi-stage staggered strip-hole motor rotor sleeve according to claim 1, characterized in that: The sheath is made of high-strength stainless steel material.

9. The multi-stage staggered strip-hole motor rotor sleeve according to claim 8, characterized in that: The permanent magnet includes a surface-mounted structure, a Halbach array structure and a built-in structure.

10. The multi-stage staggered strip-hole motor rotor sleeve according to claim 9, characterized in that: The magnetization method of the permanent magnet is determined according to the specific structure, and the magnetization method includes radial magnetization and parallel magnetization.

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