A motor rotor and a permanent magnet brushless motor having the same

Abstract

The application relates to a motor rotor and a permanent magnet brushless motor with the rotor, which comprises a rotor core and a magnetic steel, the rotor core comprises a first rotor lamination and a second rotor lamination, the first rotor lamination is externally provided with a protruding part, the second rotor lamination is externally provided with a groove part, the magnetic steel is fixed between the protruding parts of the first rotor lamination and simultaneously fixed between the groove parts of the second rotor lamination; the first rotor lamination is arranged at the front part, the rear part or the front and rear parts of the second rotor lamination. Compared with the prior art, the application has the advantages of reducing the magnetic flux leakage of the motor as much as possible under the condition of ensuring the unchanged motor output.

Description

Technical Field

[0001] This invention relates to an electric motor, and more particularly to an electric motor rotor and a permanent magnet brushless motor having the rotor. Background Technology

[0002] Traditional permanent magnet brushless motor rotor structures are divided into two types: magnets are glued to the surface of the rotor core and magnets are inserted into the inside of the rotor core. When the magnets are placed on the surface of the rotor core, it is particularly important to fix the magnets in order to prevent them from being thrown out when the rotor rotates. Generally, they are fixed to the outside of the magnets by means of Kevlar wire or steel sleeve.

[0003] In addition, when attaching magnets to the outside of the rotor, the positioning between the magnets is also very important. Inaccurate positioning will affect the cogging torque of the motor, which will lead to abnormal torque fluctuations and increased vibration and noise during operation.

[0004] like Figure 1 As shown, the rotor structure of the existing permanent magnet brushless motor in Scheme 1 includes a first existing rotor core 1 and a magnet 2. There are protrusions 3 on the outside of the rotor core. The magnet 2 is fixed between the protrusions 3 on the outside of the first existing rotor core 1. In this way, the positioning of the magnet on the outside of the rotor is solved. However, the problem is that the protrusions on the outside of the rotor core will cause magnetic leakage of the magnet, which will reduce the torque of the motor. At the same time, the magnet needs to be fixed to the outside of the rotor with glue.

[0005] The existing solution will reduce the motor torque, and bonding the magnets will increase the working time.

[0006] To reduce magnetic leakage caused by the positioning protrusion while maintaining the magnet's positioning and eliminating the need for adhesive, a second solution is adopted, as shown in Figure 2. The original magnet protrusion is hollowed out to form a dovetail groove 5, preventing magnetic leakage and increasing motor torque. Simultaneously, a plastic part 6 (or other non-magnetic material) is inserted into the dovetail groove 5. The plastic part 6 consists of two dovetails; the smaller dovetail mates with the dovetail groove 5 of the second existing rotor core 4, while the larger outer dovetail is used to fix the magnet. The combination of the plastic part 6 and the second existing rotor core 4 can be either as a separate component inserted into the second existing rotor core 4, followed by the insertion of the magnet; or the second existing rotor core 4 can be used as an insert, injection molded to form a single piece of the second existing rotor core 4 and the plastic part 6, before the magnet is inserted.

[0007] The existing option 2 would increase the manufacturing process of the motor by injection molding or inserting plastic parts, thus increasing the cost of the motor. Summary of the Invention

[0008] The purpose of this invention is to overcome the defects of the prior art and provide a motor rotor and a permanent magnet brushless motor having a rotor.

[0009] The objective of this invention can be achieved through the following technical solutions:

[0010] According to one aspect of the present invention, an electric motor rotor is provided, comprising a rotor core and magnets. The rotor core includes a first rotor lamination and a second rotor lamination. The first rotor lamination has a protrusion on its outer surface, and the second rotor lamination has a groove on its outer surface. The magnets are fixed between the protrusions of the first rotor lamination and simultaneously fixed between the grooves of the second rotor lamination. The first rotor lamination is disposed at the front, rear, or front and rear of the second rotor lamination.

[0011] As a preferred technical solution, the first rotor lamination has at least one piece.

[0012] As a preferred technical solution, the first rotor lamination is a lamination made of a non-magnetic material, preferably stainless steel.

[0013] As a preferred technical solution, when the first rotor lamination is made of stainless steel, it is positioned and fixed on the motor shaft by pressing in sections.

[0014] As a preferred technical solution, the first rotor lamination and the second rotor lamination are provided with positioning internal holes.

[0015] As a preferred technical solution, the magnet is fixed with glue.

[0016] As a preferred technical solution, the first rotor lamination has a dovetail portion for fixing the magnet.

[0017] As a preferred technical solution, the dovetail portion includes a first dovetail portion for fitting the arc portion of the magnet and a second dovetail portion for fitting the straight portions on both sides of the magnet.

[0018] As a preferred technical solution, the maximum outer diameter R1 of the magnet after it is installed on the rotor core is greater than or equal to the outer radius R2 of the dovetail.

[0019] According to another aspect of the present invention, a permanent magnet brushless motor with a rotor is provided, comprising a motor stator and the said motor rotor.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1) The rotor structure of this invention ensures that the motor output remains constant while minimizing the leakage flux of the motor. At the same time, it ensures the convenience of rotor manufacturing process and reduces the manufacturing cost of the motor.

[0022] 2) The invention solves the problem of axial positioning of the magnet by setting the first rotor lamination and solves the problem of magnetic leakage of the magnet by setting the second rotor lamination. When the material of the first rotor lamination is non-magnetic stainless steel, the magnetic leakage of the magnet is completely eliminated.

[0023] 3) This invention achieves positioning and fixation on the motor shaft by segmented pressing, which further improves the motor performance. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the existing scheme 1;

[0025] Figure 2(a) is a schematic diagram of the existing scheme 2;

[0026] Figure 2(b) is a schematic diagram of the structure after adding plastic parts to the existing scheme 2;

[0027] Figure 2(c) is a schematic diagram of the three-dimensional structure after assembly of the existing Scheme 2;

[0028] Figure 3 This is a schematic diagram of the structure of the first rotor lamination in Example 1;

[0029] Figure 4 This is a schematic diagram of the structure of the second rotor lamination in Example 1;

[0030] Figure 5 This is a schematic diagram of the three-dimensional structure after assembly in Example 1;

[0031] Figure 6 This is a schematic diagram of the structure of the first rotor lamination in Example 2;

[0032] Figure 7 This is a schematic diagram of the three-dimensional structure after assembly in Example 2;

[0033] Figure 8 This is a schematic diagram of the main structure after assembly in Example 2;

[0034] Wherein 1 is the first existing rotor core, 2 is the magnet, 3 is the protrusion, 4 is the second existing rotor core, 5 is the dovetail groove, 6 is the plastic part, 11 is the first rotor lamination, 12 is the second rotor lamination, 23 is the first dovetail, and 24 is the second dovetail. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0036] Example 1

[0037] like Figure 3 and Figure 4 As shown, an electric motor rotor includes a rotor core and a magnet 2. The rotor core includes a first rotor lamination 11 and a second rotor lamination 12. The first rotor lamination 11 has a protrusion on its exterior, and the second rotor lamination 12 has a groove on its exterior. The magnet 2 is fixed between the protrusions of the first rotor lamination 11 and between the grooves of the second rotor lamination 12. The first rotor lamination 11 is located at the front, rear, or front and rear of the second rotor lamination 12.

[0038] In this approach, the magnet still needs to be fixed to the outside of the rotor with glue.

[0039] like Figure 5 As shown, this embodiment uses two types of rotor laminations. The first rotor lamination 11 is identical in shape to the rotor lamination in the existing scheme 1; however, the material of the first rotor lamination 11 can be stainless steel. Using the first rotor lamination 11 solves the axial positioning problem of the magnet. The second rotor lamination 4 solves the problem of magnetic leakage of the magnet. When the material of the first rotor lamination 11 is the same as that of the second rotor lamination 4, the magnet will have a small amount of magnetic leakage at the front and rear parts of the rotor core, specifically at the first rotor lamination 11. When the material of the second rotor lamination 11 is non-magnetic stainless steel, the magnetic leakage of the magnet is completely eliminated.

[0040] When the rotor laminations at both ends of the rotor core are made of non-magnetic stainless steel, they can be positioned and fixed on the motor shaft by pressing them in sections.

[0041] The specific method is to first position the rotor cores through the built-in holes on the rotor laminations (insert the mandrels into the built-in holes), fix the positions of the front and rear rotor cores and the middle rotor cores in the circumferential direction in sequence, and then press the motor shaft into the front rotor core, the middle rotor core and the rear rotor core in sequence. The mandrels ensure that the three rotor cores are positioned neatly in the circumferential direction, and the motor rotor ensures that the three rotor cores are tightly connected in the axial direction.

[0042] Example 2

[0043] like Figure 6 and 7As shown, an electric motor rotor includes a rotor core and a magnet 2. The rotor core includes a first rotor lamination 11 and a second rotor lamination 12. The first rotor lamination 11 has a protrusion on its exterior, and the second rotor lamination 12 has a groove on its exterior. The magnet 2 is fixed between the protrusions of the first rotor lamination 11 and between the grooves of the second rotor lamination 12. The first rotor lamination 11 is located at the front, rear, or front and rear of the second rotor lamination 12.

[0044] The outer side of the first rotor lamination 11 has a dovetail for fixing the magnet. The first dovetail 23 and the second dovetail 24 respectively match the arc portion and the straight portions on both sides of the magnet; R2 is the outer radius of the dovetail portion where the first rotor lamination 11 is located, and R1 is the maximum outer diameter of the magnet after it is installed on the rotor core. R1 ≥ R2. Figure 8 As shown.

[0045] In this solution, the magnet does not need to be fixed to the outside of the rotor with glue.

[0046] Setting the first rotor lamination 11 solves the problem of axial positioning of the magnet, and setting the second rotor lamination 4 solves the problem of magnetic leakage of the magnet. The first rotor lamination 11 is made of non-magnetic stainless steel, so the magnetic leakage of the magnet is completely eliminated.

[0047] When the rotor laminations at both ends of the rotor core are made of non-magnetic stainless steel, they can be positioned and fixed on the motor shaft by pressing them in sections.

[0048] The specific method is to first position the rotor cores through the built-in holes on the rotor laminations (insert the mandrels into the built-in holes), fix the positions of the front and rear rotor cores and the middle rotor cores in the circumferential direction in sequence, and then press the motor shaft into the front rotor core, the middle rotor core and the rear rotor core in sequence. The mandrels ensure that the three rotor cores are positioned neatly in the circumferential direction, and the motor rotor ensures that the three rotor cores are tightly connected in the axial direction.

[0049] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An electric machine rotor comprising a rotor core and a magnetic steel (2), characterized in that, The rotor core includes a first rotor lamination (11) and a second rotor lamination (12). The first rotor lamination (11) has a protrusion on its outside, and the second rotor lamination (12) has a groove on its outside. The magnet (2) is fixed between the protrusions of the first rotor lamination (11) and between the grooves of the second rotor lamination (12). The first rotor lamination (11) is located at the front, rear, or front and rear of the second rotor lamination (12).

2. An electric machine rotor according to claim 1, characterized in that The first rotor lamination (11) has at least one piece.

3. The motor rotor according to claim 1, characterized in that, The first rotor lamination (11) is a lamination made of a non-magnetic material, preferably stainless steel.

4. The motor rotor according to claim 3, characterized in that, When the first rotor lamination (11) is made of stainless steel, it is positioned and fixed on the motor shaft by pressing it in sections.

5. A motor rotor according to claim 4, characterized in that, The first rotor lamination (11) and the second rotor lamination (12) are provided with positioning internal holes.

6. The motor rotor according to claim 1, characterized in that, The magnet (2) is fixed with glue.

7. The motor rotor according to claim 1, characterized in that, The first rotor lamination (11) has a dovetail portion for fixing the magnet (2) on its outer side.

8. The motor rotor according to claim 7, characterized in that, The dovetail portion includes a first dovetail portion (23) for fitting the arc portion of the magnet (2) and a second dovetail portion (24) for fitting the straight portions on both sides of the magnet (2).

9. A motor rotor according to claim 7, characterized in that, The maximum outer diameter R1 of the magnet (2) after it is installed on the rotor core is greater than or equal to the outer radius R2 of the dovetail.

10. A permanent magnet brushless motor with a rotor, characterized in that, It includes the motor stator and the motor rotor as described in any one of claims 1-9.

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