Rotor

Abstract

A rotor comprises a rotor main body and a rotating shaft, and the rotor main body comprises magnetic steel grooves; the radial outer side of each magnetic steel groove is correspondingly provided with an arc part, and the arc parts are located on the outer peripheral surface of the rotor body. At least one concave part is arranged between every two adjacent arc parts, and at least one transition structure is arranged between every two adjacent concave parts. The concave part is positioned on the outer peripheral surface of the rotor main body and is connected to the arc part; the transition structure is positioned on the outer peripheral surface of the rotor main body and is connected to the concave part; the distance from the transition structure to the vertical line of the center line of the rotor body is not larger than the radius of the arc portion, and the minimum distance from the concave portion to the vertical line of the center line of the rotor body is not larger than the minimum distance from the transition structure to the vertical line of the center line of the rotor body. According to the arrangement, the concave part is connected with the positioning part through the transition structure, so that the structural strength of the rotor main body can be improved, and certain manufacturing cost can be reduced.

Description

[TECHNICAL FIELD]

[0001] The present application relates to the technical field of electric machines, in particular to a rotor. [BACKGROUND]

[0002] A brushless motor mainly comprises a rotor, a stator and an electronic commutator (a brushless motor controller), which replaces the original brush for commutation, has the advantages of high efficiency, long service life, easy control, etc., and is widely used in many fields such as electric tools, portable electronic devices, etc.

[0003] The rotor core of the brushless motor is provided with a magnetic steel, and after the installation of the magnetic steel is completed, the magnetic steel needs to be magnetized, so a positioning groove is formed on the outer circumferential surface of the rotor core to position the position of the magnetic steel. However, the position of the positioning groove will affect the performance of the brushless motor, especially the arc extinction of the rotor core will reduce the back electromotive force of the brushless motor, and increase the cogging torque of the brushless motor, which affects the output of the brushless motor; in addition, the brushless motor controlled by a square wave is also prone to electromagnetic noise problems, which affects the user experience. Therefore, in the prior art, a groove is formed on the outer circumferential surface of the rotor core and adjacent to the end of the magnetic steel to improve the above problems.

[0004] After the positioning groove and the groove are formed on the outer circumferential surface of the rotor core, in order to improve the performance of the brushless motor, the length of the magnetic steel needs to be increased as much as possible, at this time the structural strength between the magnetic steel slot and the rotor core is affected, and the rotor core may fail during operation.

[0005] Therefore, it is necessary to provide an improved rotor to overcome the defects in the prior art. [SUMMARY]

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a rotor with higher structural strength.

[0007] The technical scheme adopted by the present application to solve the problems of the prior art is: a rotor, comprising a rotor body and a rotating shaft fixed to the center of the rotor body, the rotor body comprising a magnetic steel slot penetrating through the two axial ends, and a magnetic steel being installed in the magnetic steel slot; a circular arc part is provided on the radial outer side of each magnetic steel slot, and the circular arc part is located on the outer circumferential surface of the rotor body; at least one recess is included between two adjacent circular arc parts, and the recess is located on the outer circumferential surface of the rotor body and connected to the circular arc part; at least one transition structure is included between two adjacent recesses, and the transition structure is located on the outer circumferential surface of the rotor body and connected to the recess, the distance from the transition structure to the perpendicular line of the center line of the rotor body is not greater than the radius of the circular arc part, and the minimum distance from the recess to the perpendicular line of the center line of the rotor body is not greater than the minimum distance from the transition structure to the perpendicular line of the center line of the rotor body.

[0008] Further improvement scheme is that the outer circumferential surface of the rotor body further comprises a positioning portion between two adjacent transition structures, and the minimum distance from the positioning portion to the vertical line of the center line of the rotor body is not greater than the minimum distance from the recess to the vertical line of the center line of the rotor body.

[0009] Further improvement scheme is that, in the radial direction of the rotor body, the recess, the transition structure and the positioning portion are recessed towards the center line of the rotor body, and the recessing degree of the transition structure in the circumferential direction is smaller than that of the recess and the positioning portion.

[0010] Further improvement scheme is that the magnetic steel slot comprises a mounting portion and a special-shaped portion at both ends of the mounting portion, the magnetic steel is inserted into the mounting portion, the shape and size of the magnetic steel are matched with the shape and size of the mounting portion, and the chord of the circular arc portion is parallel to the long side of the mounting portion.

[0011] Further improvement scheme is that the special-shaped portion comprises a connecting arc connected to the mounting portion, the curvature of the connecting arc is the same as that of the transition structure, the connecting arc and the transition structure are arranged in parallel and are spaced apart, and the distance between the connecting arc and the transition structure is not less than 0.3 mm.

[0012] Further improvement scheme is that the contour line of the recess is a first arc line, the contour line of the transition structure is a second arc line, and the contour line of the positioning portion is a third arc line; the first arc line, the second arc line and the third arc line are all circular arcs, and the connecting line between the center of the third arc line and the center line of the rotor body does not pass through the magnetic steel slot.

[0013] Further improvement scheme is that the positioning portion is at least partially located between the gaps of two adjacent magnetic steel slots in the circumferential direction, and the end portion of the magnetic steel slot extends to the position of the transition structure.

[0014] Another technical solution adopted by the present application to solve the problems of the prior art is: 8. A rotor comprising a rotor body and a rotating shaft fixed at the center of the rotor body, the rotor body comprising a magnetic steel slot penetrating through the two axial ends, and a magnetic steel being installed in the magnetic steel slot; a circular arc portion is arranged on the outer circumferential surface of the rotor body corresponding to the radial outer side of each magnetic steel slot; at least one recess is arranged between two adjacent circular arc portions, the recess is located on the outer circumferential surface of the rotor body and connected to the circular arc portion; the outer circumferential surface of the rotor body further comprises at least one positioning portion between two adjacent circular arc portions, and a transition structure is arranged between the recess and the positioning portion, the transition structure connects the recess and the positioning portion in the circumferential direction.

[0015] Further improvement scheme is that each of the two ends of the arc part includes the concave part, and the positioning part is arranged between the two adjacent transition structures.

[0016] Further improvement scheme is that the magnetic steel slot includes a mounting part and a special-shaped part arranged at the two ends of the mounting part, the magnetic steel is inserted into the mounting part, and the shape and size of the magnetic steel are matched with the shape and size of the mounting part; and the chord of the arc part is parallel to the long side of the mounting part.

[0017] Further improvement scheme is that the special-shaped part includes a connecting arc connected to the mounting part, the connecting arc has the same shape as the transition structure, and the connecting arc and the transition structure are arranged in parallel and at intervals.

[0018] Further improvement scheme is that, in the radial direction of the rotor body, the concave part, the transition structure and the positioning part are arranged in a recessed manner towards the center line of the rotor body, the distance from the concave part, the transition structure and the positioning part to the vertical line of the center line of the rotor body is not greater than the radius of the arc part, and the recessed degree of the transition structure in the circumferential direction is smaller than that of the positioning part and the concave part.

[0019] Compared with the prior art, the present application has the following beneficial effects: at least one concave part is arranged between two adjacent arc parts, and at least one transition structure is arranged between two adjacent concave parts; the concave part is arranged on the outer circumferential surface of the rotor body and connected to the arc part, and the transition structure is arranged on the outer circumferential surface of the rotor body and connected to the concave part; the distance from the transition structure to the vertical line of the center line of the rotor body is not greater than the radius of the arc part, and the minimum distance from the concave part to the vertical line of the center line of the rotor body is not greater than the minimum distance from the transition structure to the vertical line of the center line of the rotor body; the curvature of the connecting arc is the same as that of the transition structure, and the connecting arc and the transition structure are arranged in parallel and at intervals. In this way, the concave part is arranged on the outer circumferential surface of the rotor body to optimize the counter electromotive force of the rotor, reduce the cogging torque of the rotor and reduce the electromagnetic noise during the operation of the rotor; the concave part and the positioning part are connected through the transition structure, which can improve the structural strength of the rotor body and reduce the manufacturing cost. [BRIEF DESCRIPTION OF DRAWINGS]

[0020] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings:

[0021] Figure 1 is a perspective view of the rotor of the preferred embodiment of the present application;

[0022] Figure 2 is Figure 1 a sectional view of the rotor shown in the figure;

[0023] Figure 3 is Figure 1 another sectional view of a partial structure of the rotor shown in FIG. 1;

[0024] Figure 4 is Figure 1 a schematic view of the rotor lamination shown in FIG. 1;

[0025] Figure 5 is Figure 4 a partial enlarged view of the rotor lamination shown in FIG. 1;

[0026] Figure 6 is Figure 1 a back-EMF curve graph of the rotor shown in FIG. 1;

[0027] Figure 7 is Figure 1 a back-EMF Fourier transform graph of the rotor shown in FIG. 1;

[0028] Figure 8 is Figure 1 a cogging torque graph of the rotor shown in FIG. 1. [DETAILED DESCRIPTION]

[0029] The terms used in the present application are merely for the purpose of describing particular embodiments and are not intended to limit the present application. For example, the words "upper", "lower", "front", "rear", and the like, which indicate spatial or positional relationships based on the orientation or position shown in the drawings, are used only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device / element referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the present application.

[0030] Referring to Figures 1 to 5 A rotor 100 according to the present application is shown in FIG. 1. The rotor 100 is installed to a brushless motor (not shown) and rotates by electromagnetic induction, and in turn transmits power to an output shaft (not shown) to drive a tool to operate. The rotor 100 according to the present application is a rotor of a brushless motor, and does not need to be commutated by a brush, but is commutated by a controller electrically connected to a stator (not shown).

[0031] Referring to Figure 1 with Figure 2As shown, the rotor 100 comprises a rotor body 1, a rotating shaft 2 fixed at the center of the rotor body 1, a magnetic steel 3 inserted into the rotor body 1, a balancing member 4 located at the axial ends of the rotor body 1, an injection body 5 spacing the rotating shaft 2 and the rotor body 1, and a fan 6 fixed at the axial end of the rotating shaft 2; the rotor 100 is used for a high-voltage brushless motor, and thus the rotating shaft 2 and the rotor body 1 need to be insulated. After the rotor body 1 is sleeved on the rotating shaft 2, the two are placed in a tool jig, the gap between the two is BMC injection molded to form the injection body 5; at the same time, the two balancing members 4 are placed at the axial ends of the rotor body 1 during injection molding, and are integrally injection molded, so that the injection body 5 connects the rotor body 1, the rotating shaft 2 and the balancing member 4 into one whole.

[0032] Further, milling or drilling can be performed on the end face or the peripheral surface of the balancing member 4 to improve the balance of the rotor 100 during rotation.

[0033] The rotor body 1 comprises a magnetic steel groove 11 penetrating through the axial ends, the magnetic steel 3 is inserted and fixed into the magnetic steel groove 11, and the balancing member 4 is tightly attached to the two ends of the rotor body 1, so that the magnetic steel 3 can be reliably retained in the magnetic steel groove 11 and will not be separated from the magnetic steel groove 11 due to the rotation of the rotor 100. In the present embodiment, the shape of the magnetic steel 3 is square, the magnetic steel groove 11 comprises a mounting portion 111 matched with the shape of the magnetic steel 3 and a special-shaped portion 112 at the two ends of the mounting portion, and the magnetic steel 11 is inserted into the mounting portion 111.

[0034] Please refer to Figure 3 The rotor body 1 is formed by stacking a plurality of rotor laminations 10 along the central axis of the rotor 100, and each rotor lamination 10 has the same shape and size.

[0035] The rotor body 1 comprises a circular arc portion 12 located radially outside the magnetic steel groove 11, the circular arc portion 12 is located on the outer peripheral surface of the rotor body 1, the number of the circular arc portions 12 is equal to the number of the magnetic steels 3, and the chord L of the circular arc portion 12 is parallel to the long side of the mounting portion 111; in the present embodiment, the number of the magnetic steels 3 and the circular arc portions 12 is four, and alternatively, the number of the two can be set to six, eight, ten, twelve or the like according to the design requirements of the rotor.

[0036] Further, the rotor body 1 further comprises a recess 13, a transition structure 14 and a positioning portion 15 between two adjacent circular arc portions 12 in the circumferential direction. The recess 13 is located at the end of the circular arc portion 12 and connected with the circular arc portion 12, and the number of the recess 13 is twice the number of the magnetic steel 3; the positioning portion 15 is at least partially located between the gap of two adjacent magnetic steel slots 11 in the circumferential direction, and the number of the positioning portion 15 is equal to the number of the magnetic steel 3; the recess 13 and the positioning portion 15 are connected by the transition structure 14, and the number of the transition structure 14 is equal to the number of the recess 13. A pair of recesses 13, a pair of transition structures 14 and a positioning portion 15 are arranged between two adjacent circular arc portions 12; the pair of transition structures 14 and the positioning portion 15 are located between the pair of recesses 13, and the positioning portion 15 is located between the pair of transition structures 14.

[0037] In the present embodiment, the positioning portion 15 is recessed, and the positioning portion 15 is used for positioning by a tool jig when the rotor 100 is magnetized.

[0038] Please refer to Figure 4 and Figure 5 , wherein Figure 5 is a partial enlarged view of a quarter structure of the rotor lamination 10; each rotor lamination 10 comprises the circular arc portion 12, the recess 13, the transition structure 14, the positioning portion 15 and the magnetic steel slot 11 described above, and the structure will be further described below by the rotor lamination 10.

[0039] The shape of the rotor lamination 10 is approximately circular, the center of the rotor lamination 10 is the center O of the circular arc portion 12, the distance from the recess 13 to the center O is not greater than the radius of the circular arc portion 12, the distance from the transition structure 14 to the center O is not greater than the radius of the circular arc portion 12, and the distance from the positioning portion 15 to the center O is not greater than the radius of the circular arc portion 12; in the present embodiment, the maximum radial dimension of the rotor lamination 10 is the radius of the circular arc portion 12, the recess 13, the transition structure 14 and the positioning portion 15 are recessed, and the contour line of the recess 13 is a first arc line, the contour line of the transition structure 14 is a second arc line, and the contour line of the positioning portion 15 is a third arc line; the centers of the first arc line, the second arc line and the third arc line are located on the radial outside of the rotor lamination 10.

[0040] In the radial direction of the rotor lamination 10, the recess 13, the transition structure 14 and the positioning portion 15 are recessed towards the center O, the recessing degree of the transition structure 14 in the circumferential direction is less than that of the positioning portion 15 and the recess 13; the radius range of the recess 13 is 2mm-20mm, the radius range of the transition structure 14 is 3mm-30mm, and the radius range of the positioning portion 15 is 0.5-2mm.

[0041] The positioning part 15 is located between two adjacent profiled parts 112 in the circumferential direction, and the line connecting the center of the positioning part 15 and the center O of the rotor lamination 10 does not pass through the magnetic steel slot 11. The positioning part 15 is used to position the magnetic steel 3 after the rotor body 1 is installed with the magnetic steel 3.

[0042] In the embodiment, one circular arc part 12, one pair of recessed parts 13 and one pair of transition structures 14 are arranged on the radially outer side of each magnetic steel 3. The pair of recessed parts 13 are arranged near the two ends of the magnetic steel 3, and the pair of transition structures 14 are arranged near the profiled part 112. Compared with the rotor lamination with a whole circular shape, the arrangement of the recessed parts 13 on the radially outer side of the two ends of the magnetic steel 3 can optimize the back electromotive force waveform of the brushless motor, improve the proportion of the fundamental wave and reduce the harmonic component without reducing the back electromotive force increase value. At the same time, the arrangement can reduce the cogging torque of the brushless motor and reduce the electromagnetic noise in the operation process of the brushless motor.

[0043] The profiled part 112 of the magnetic steel slot 11 includes a connecting arc 113 connected with the mounting part 111. The connecting arc 113 is a fourth arc line, the curvature of the connecting arc 113 is equal to the curvature of the transition structure 14 (i.e. the radii of the two are equal), the arc length of the connecting arc 113 is not equal to the arc length of the transition structure 14, and the connecting arc 113 and the transition structure 14 are arranged in parallel (i.e. one can be obtained by translating the other along a certain line), and the distance between the two is not less than 0.3 mm (the part where the two are parallel to each other). In the embodiment, the arrangement of the profiled part 112 can improve the magnetic saturation of the brushless motor, thereby improving the performance of the brushless motor. At the same time, the equal curvature and parallel arrangement of the connecting arc 113 of the transition structure 14 and the profiled part 112 make the structural strength of the rotor lamination 10 at this position higher. Secondly, the gap between the transition structure 14 and the magnetic steel slot 11 at this position is made smaller (the minimum value is 0.3 mm), which improves the length of the magnetic steel 3 that can be placed, and further improves the performance of the brushless motor.

[0044] Please refer to Figure 4 and Figure 5 As shown in the figures, the rotor lamination 10 is defined by a first radial line R1, a second radial line R2 and a third radial line R3. The first radial line R1 is collinear with the radius of the upper circular arc part 12 in the vertical direction, i.e. the ray between the center O and the bisector point of the upper circular arc part 12 is the first radial line R1; the second radial line R2 is the line connecting the center O and the center of the recessed part 13, and the third radial line R3 is the line connecting the center O and the center of the transition structure 14. The smaller angle between the second radial line R2 and the first radial line R1 is in the range of 25°-30°, and the smaller angle between the third radial line R3 and the first radial line R1 is in the range of 36°-39°. The four positioning parts 15 are evenly distributed on the outer circumferential surface of the rotor lamination 10 with an interval of 90°.

[0045] The distance between the recess 13 closest to the center O and the circular arc part 12 is a first distance D1, and the distance between the positioning part 15 closest to the center O and the circular arc part 12 is a second distance D2; the first distance D1 ranges from 0.2mm to 0.5mm, and the second distance D2 ranges from 0.2mm to 1mm.

[0046] Please refer to Figures 6 to 8 As shown in the figure, Figure 6 The figure is a comparison of the back electromotive force curve of the rotor 100 in the present scheme and the back electromotive force curve of the rotor without the recess (original scheme) in operation, wherein the black solid line is the back electromotive force curve of the rotor 100 in the present scheme, and the black dashed line is the back electromotive force curve of the rotor in the original scheme. Figure 7 The figure is a comparison of the back electromotive force Fourier transform of the rotor 100 in the present scheme and the Fourier transform of the rotor without the recess (original scheme) in operation, wherein the black filled box is the back electromotive force Fourier transform of the rotor 100 in the present scheme, and the box without color filling in the black line frame is the back electromotive force Fourier transform of the rotor in the original scheme. Figure 8 The figure is a comparison of the cogging torque of the rotor 100 in the present scheme and the cogging torque of the rotor without the recess (original scheme) in operation, wherein the black solid line is the cogging torque of the rotor 100 in the present scheme, and the black dashed line is the cogging torque of the rotor in the original scheme. Figure 6 And Figure 7 It can be known that, in the present scheme, the rotor 100 is optimized in the waveform of the back electromotive force without reducing the back electromotive force value, and the proportion of the fundamental wave is improved on the basis of the original back electromotive force, the harmonic cost is reduced, and the performance of the motor is improved. Figure 8 It can be known that, in the present scheme, the rotor 100 is obviously reduced in the cogging torque, and the electromagnetic noise in the operation process of the brushless motor is reduced.

[0047] The present application is not limited to the above-mentioned specific embodiments. Those skilled in the art can easily understand that the rotor of the present application has many alternative schemes without departing from the principles and categories of the present application. The protection scope of the present application is subject to the contents of the claims.

Claims

1. A rotor comprising a rotor body and a rotating shaft fixed in the center of the rotor body, the rotor body comprising a magnetic steel slot through the axial two ends, and a magnetic steel is installed in the magnetic steel slot; the radial outer side of each magnetic steel slot is provided with a circular arc part corresponding to the magnetic steel slot, and the circular arc part is located on the outer circumferential surface of the rotor body; at least one recess is included between the two adjacent circular arc parts, the recess is located on the outer circumferential surface of the rotor body, and the recess is connected to the circular arc part; characterized in that: At least one transition structure is included between two adjacent recesses, the transition structure is located on the outer circumferential surface of the rotor body and connected to the recess, the distance from the transition structure to the vertical line of the center line of the rotor body is not greater than the radius of the circular arc portion, and the minimum distance from the recess to the vertical line of the center line of the rotor body is not greater than the minimum distance from the transition structure to the vertical line of the center line of the rotor body.

2. The rotor of claim 1, wherein: The outer circumferential surface of the rotor body further includes a positioning portion located between two adjacent transition structures, and the minimum distance from the positioning portion to the vertical line of the center line of the rotor body is not greater than the minimum distance from the recess to the vertical line of the center line of the rotor body.

3. The rotor of claim 2, wherein: In the radial direction of the rotor body, the recess, the transition structure and the positioning portion are recessed towards the center line of the rotor body, and the recessing degree of the transition structure in the circumferential direction is smaller than that of the recess and the positioning portion.

4. The rotor of claim 1, wherein: The magnetic steel slot includes a mounting portion and a special-shaped portion located at both ends of the mounting portion, the magnetic steel is inserted into the mounting portion, and the shape and size of the magnetic steel are matched with the shape and size of the mounting portion, and the chord of the circular arc portion is parallel to the long side of the mounting portion.

5. The rotor of claim 4, wherein: The special-shaped portion includes a connecting arc connected to the mounting portion, the curvature of the connecting arc is the same as that of the transition structure, the connecting arc and the transition structure are arranged in parallel and at intervals, and the distance between the connecting arc and the transition structure is not less than 0.3 mm.

6. The rotor of claim 5, wherein: The profile line of the recess is a first arc line, the profile line of the transition structure is a second arc line, and the profile line of the positioning portion is a third arc line; the first arc line, the second arc line and the third arc line are all circular arcs, and the line connecting the center of the third arc line and the center line of the rotor body does not pass through the magnetic steel slot.

7. The rotor of claim 2, wherein: The positioning portion is at least partially located between the gaps of two adjacent magnetic steel slots in the circumferential direction, and the end portion of the magnetic steel slot extends to the position of the transition structure.

8. A rotor comprising a rotor body and a rotating shaft fixed in the center of the rotor body, the rotor body comprising a magnetic steel slot through the axial two ends, and a magnetic steel is installed in the magnetic steel slot; the radial outer side of each magnetic steel slot is provided with a circular arc part corresponding to the magnetic steel slot, and the circular arc part is located on the outer circumferential surface of the rotor body; characterized in that: At least one recess is included between two adjacent circular arc portions, the recess is located on the outer circumferential surface of the rotor body and connected to the circular arc portion; the outer circumferential surface of the rotor body further includes at least one positioning portion, the positioning portion is located between two adjacent circular arc portions, and a transition structure is further arranged between the positioning portion and the recess, the transition structure connects the recess and the positioning portion in the circumferential direction.

9. The rotor of claim 8, wherein: Both ends of each circular arc portion include the recess, and the positioning portion is included between two adjacent circular arc portions, and the positioning portion is located between two adjacent transition structures.

10. The rotor of claim 8, wherein: The magnetic steel slot includes a mounting portion and a special-shaped portion located at both ends of the mounting portion, the magnetic steel is inserted into the mounting portion, and the shape and size of the magnetic steel are matched with the shape and size of the mounting portion; the chord of the circular arc portion is parallel to the long side of the mounting portion.

11. The rotor of claim 10, wherein: The special-shaped portion includes a connecting arc connected to the mounting portion, the connecting arc and the transition structure have the same shape, and the connecting arc and the transition structure are arranged in parallel and at intervals.

12. The rotor of claim 8, wherein: In the radial direction of the rotor body, the recess, the transition structure, and the positioning portion are recessed toward the center line of the rotor body, the perpendicular distance from the recess, the transition structure, and the positioning portion to the center line of the rotor body is not greater than the radius of the circular-arc portion, and the recessed degree of the transition structure in the circumferential direction is less than the recessed degree of the positioning portion and the recess.

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