Permanent magnet motor rotor

Abstract

The utility model discloses a permanent magnet motor rotor, comprising a rotor body, the rotor body forms an iron core base body with a circular outer ring, the iron core base body comprises a plurality of rotor punching sheets formed by pressing, a transmission shaft is arranged on the central axis of the iron core base body, and the iron core base body is provided with a plurality of lightening holes arranged around the axis of the iron core base body. A group of heat dissipation holes are formed between any two adjacent lightening holes, permanent magnet grooves arranged in groups are further formed in the iron core base body, the groove edges, away from each other, of the permanent magnet grooves in each group extend towards the magnetic isolation bridge to form demagnetization-preventing extension grooves, and magnetic steel steps are in transition connection between the permanent magnet grooves and the demagnetization-preventing extension grooves of the permanent magnet grooves. The magnetic steel step is implemented in a manner of limiting and clamping the permanent magnet; according to the utility model, light weight is realized under the condition of reducing the magnetic leakage amount, innovative structural support is provided for the permanent magnets, the fastening performance of the permanent magnets is further improved, the use quality of the motor rotor is ensured, and structural deformation is effectively prevented on the premise that the magnetic isolation bridge is thinned.

Description

Technical Field

[0001] The utility model relates to a motor rotor, in particular to a permanent magnet motor rotor. Background Art

[0002] With the rapid development of new energy vehicles, the three most discussed automotive components have shifted from the traditional engine, transmission, and chassis to batteries, motors, and electronic control systems. Among them, the motor, as the power output device of electric vehicles, is particularly critical for improving the efficiency of the entire powertrain.

[0003] There are many types of motors, including DC motors, permanent magnet motors, AC asynchronous motors, and switched reluctance motors. Permanent magnet motors are a popular choice for high-performance electric vehicles, especially embedded permanent magnet synchronous motors. As electric vehicles significantly surpass traditional fuel vehicles in performance, the performance requirements for rotors and their laminations are also increasing.

[0004] To improve rotor performance and prevent the permanent magnets from being thrown away by high-speed centrifugal forces, the edges of the rotor laminations are designed to have a certain thickness. This thickness is called the magnetic isolation bridge. The thinner the magnetic isolation bridge, the greater the magnetic flux of the motor and the higher the efficiency. Current permanent magnet motor rotor designs have two extremes in terms of magnetic isolation bridge thickness: one is to make the magnetic isolation bridge too thick, which will hinder the motor's magnetic flux; the other is to make the magnetic isolation bridge too thin, which makes the structure prone to deformation.

[0005] For example: a kind of automotive permanent magnet motor rotor punching and its oblique pole structure with the publication (announcement) number CN113489189A, the rotor punching includes an inner punching and an outer punching, the center of the inner punching is provided with a shaft mounting hole for fixing the shaft, the side wall of the shaft mounting hole is provided with a plurality of shaft mating keyways, the outer wall of the inner punching is provided with a plurality of mating keys, the inner wall of the outer punching is provided with corresponding mating keyways, the inner punching and the outer punching are fixedly connected by interference fit between the mating keys and the mating keyways; the outer punching is provided with a circle of first magnetic steel grooves distributed in the inner layer and an equal circle of second magnetic steel grooves distributed in the outer layer, the outer punching is provided with a direct axis groove on the outer wall in the direct axis direction, and the outer punching is provided with a cross axis groove on the outer wall in the cross axis direction. This solution sets two different magnetic steel slots on the same punching plate (pole piece). It can be seen from the attached figure that the thickness of each magnetic steel slot is different, which means that the size of the magnetic flux and the amount of leakage magnetic flux are different, which will lead to poor consistency in the operation of the motor, and too many openings will affect the structural strength against deformation.

[0006] We propose a permanent magnet motor rotor that ensures the consistency of magnetic flux and motor performance while making the magnetic isolation bridge thinner, and effectively prevents structural deformation. Utility Model Content

[0007] In order to solve the deficiencies existing in the above technologies, the utility model provides a permanent magnet motor rotor.

[0008] In order to solve the above technical problems, the technical solution adopted by the utility model is: a permanent magnet motor rotor, including a rotor body, the rotor body forming an iron core base with a circular outer ring, the iron core base including a plurality of pressed rotor punchings, a transmission shaft is set on the central axis of the iron core base, a plurality of weight-reducing holes arranged around its axis are opened on the iron core base, a group of heat dissipation holes are opened between any two adjacent weight-reducing holes, and permanent magnet slots arranged in groups are also opened on the iron core base. The slot edges of each group of permanent magnet slots are away from each other and extend toward the magnetic isolation bridge to form anti-demagnetization extension slots. There is a magnetic steel step in the transition between the permanent magnet slots and their anti-demagnetization extension slots, and the magnetic steel step is implemented in a way of limiting and clamping the permanent magnets.

[0009] Furthermore, the rotor body rotates around the transmission shaft relative to the external stator winding.

[0010] Furthermore, a plurality of weight-reducing holes are opened around the transmission shaft in a circular array, the intervals between any two adjacent weight-reducing holes are the same, the weight-reducing holes are pentagonal, and the corners between any two adjacent sides of the weight-reducing holes are rounded.

[0011] Furthermore, the two permanent magnet slots facing the outer ring of the weight-reducing hole form a group, and magnetic ribs spaced apart from each other are formed between the two permanent magnet slots in each group.

[0012] Furthermore, the angle formed between the two permanent magnet slots in a group is 160°-180°.

[0013] Furthermore, the edge of the anti-demagnetization extension groove is an arc segment.

[0014] Furthermore, each group of heat dissipation holes includes a first heat dissipation hole and a second heat dissipation hole that are spaced apart from each other. The first heat dissipation hole and the second heat dissipation hole are both circular holes, and the second heat dissipation hole is implemented in a manner of being closer to the transmission shaft.

[0015] Furthermore, the outer ring of the first heat dissipation hole is provided with oil circulation holes, and the number of the oil circulation holes corresponds to the number of groups of the heat dissipation holes.

[0016] Furthermore, a support rib is processed in the lightening hole, and the support rib is located at one-half of the lightening hole and overlaps with the radial extension line of the transmission shaft.

[0017] A permanent magnet motor rotor is designed to reduce magnetic leakage while achieving lightweightness through the hole design of the rotor punching sheets. The extended setting of the permanent magnet slots and the transition connection limit provide innovative structural support for the permanent magnets, further improving the tightness of the permanent magnets, ensuring the quality of the motor rotor, and effectively preventing structural deformation while making the magnetic isolation bridge thinner. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a structural diagram of Example 1 of the present utility model.

[0019] Figure 2 This is an excerpt from the rotor punching structure of Example 2 of the present utility model.

[0020] In the figure: 1. Rotor body; 2. Drive shaft; 3. Iron core base; 4. Rotor punching; 5. Permanent magnet slot; 6. Magnetic isolation bridge; 7. Magnetic steel step; 8. Weight reduction hole; 9. Anti-demagnetization extension slot; 10. Arc segment; 11. Oil circulation hole; 12. First heat dissipation hole; 13. Second heat dissipation hole; 14. Support rib. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0022] like Figure 1 As shown, Figure 1-2 As shown in the figure, the present application is about a permanent magnet motor rotor, which belongs to the category of embedded permanent magnet motor.

[0023] The present application includes a rotor body 1, which forms an iron core base 3 with a circular outer ring. The iron core base 3 includes a rotor punching 4 formed by pressing several pieces. The pressing method and structural composition are existing technologies, so the specific pressing does not fall within the scope of protection of this embodiment.

[0024] On this basis, a transmission shaft 2 is set on the central axis of the core base 3, and a number of weight-reducing holes 8 arranged around its axis are opened on the core base 3 to improve the lightweight of the core base 3. A group of heat dissipation holes is opened between any two adjacent weight-reducing holes 8 to improve the heat dissipation capacity of the rotor body 1 when working. The core base 3 is also provided with permanent magnet slots 5 arranged in groups, which are used to install permanent magnets. The slot edges of each group of permanent magnet slots 5 are away from each other and extend toward the magnetic isolation bridge 6 to form anti-demagnetization extension slots 9. The anti-demagnetization extension slots 9 are used to fasten the permanent magnets to prevent the permanent magnets from moving. There is a magnetic steel step 7 in the transition between the permanent magnet slot 5 and its anti-demagnetization extension slot 9. The magnetic steel step 7 is implemented in a way of limiting and clamping the permanent magnet. That is, when the permanent magnet is installed in the permanent magnet slot 5, the magnetic steel step 7 abuts against the permanent magnet, and the permanent magnet is limited and clamped by the physical obstruction of the abutment.

[0025] The rotor body 1 rotates around the transmission shaft 2 relative to the external stator winding, thereby generating kinetic energy.

[0026] The angle formed between the two permanent magnet slots 5 in a group is 160°-180°, that is, the magnetic circuit structure of the present application is a hybrid type.

[0027] The edge of the anti-demagnetization extension slot 9 is an arc segment 10, and the transition is more natural. Compared with the angle transition, the force on the arc segment 10 is more dispersed, and the stress will not be too concentrated at the bending position like the angle transition, which can improve the service life.

[0028] Example 1

[0029] On this common basis, several weight-reducing holes 8 in this embodiment are opened around the transmission shaft 2 in a circular array. The intervals between any two adjacent weight-reducing holes 8 are the same. The weight-reducing holes 8 are pentagonal, and the corners between any two adjacent sides of the weight-reducing holes 8 are rounded, which facilitates the processing of the rotor punching 4.

[0030] The two permanent magnet slots 5 facing the outer circle of the weight-reducing hole 8 form a group, and magnetic ribs spaced apart from each other are formed between the two permanent magnet slots 5 in each group. That is to say, the two permanent magnet slots 5 in each group are not connected to each other, which further improves the tightness of the permanent magnet and prevents the permanent magnet from loosening or detaching.

[0031] In this embodiment, if Figure 1 As shown, the angle formed between the two permanent magnet slots 5 in a group is 160°. By limiting the degree of the angle between the two permanent magnet slots 5, the opening structure of the rotor punching 4 and the entire core matrix 3 is changed. In actual operation, the high-speed rotation of the rotor body 1 will test the strength of the rotor punching 4 and the core matrix 3, especially prone to structural deformation. The 160° angle setting of this embodiment weakens the deflection force on the permanent magnet in the permanent magnet slot 5. Combined with the structural form of the magnetic steel step 7 abutting the permanent magnet, the fastening state of the permanent magnet is further improved.

[0032] In this embodiment, each group of heat dissipation holes includes a first heat dissipation hole 12 and a second heat dissipation hole 13 spaced apart from each other. The first heat dissipation hole 12 and the second heat dissipation hole 13 are both circular holes, and the second heat dissipation hole 13 is implemented in a manner closer to the transmission shaft 2. The performance of the rotor is closely related to its heat dissipation effect. Compared with the traditional heat dissipation design, this embodiment arranges the heat dissipation holes in groups. Each group is provided with two heat dissipation holes, the first heat dissipation hole 12 and the second heat dissipation hole 13, which is twice the number of the traditional ones, and the heat dissipation effect is better. In addition, combined with the above-mentioned optimization of the opening structure of the rotor punching 4 and the iron core matrix 3, the structural stability can meet actual needs, and there is no need to worry about structural collapse caused by multiple heat dissipation holes.

[0033] On this basis, the outer ring of the first heat dissipation hole 12 is provided with an oil circulation hole 11. The number of the oil circulation holes 11 corresponds to the number of groups of heat dissipation holes. The oil circulation holes 11 are used to connect with the oil hole oil circuit of the outer end ring. In addition, in the prior art, the oil circulation holes 11 are as follows. Figure 1The shape shown is a unique setting of this embodiment. The oil flow hole 11 of this embodiment is set to be narrow and long, which on the one hand ensures the flow volume of the oil circuit, and on the other hand avoids structural collapse caused by the opening being too large.

[0034] Example 2

[0035] On the basis of common implementation, this embodiment is the same as Example 1 in that several weight-reducing holes 8 in this embodiment are opened around the transmission shaft 2 in a circular array, the intervals between any two adjacent weight-reducing holes 8 are the same, the weight-reducing holes 8 are pentagonal, and the corners between any two adjacent sides of the weight-reducing holes 8 are rounded, which facilitates the processing of the rotor punching 4.

[0036] The two permanent magnet slots 5 facing the outer circle of the weight-reducing hole 8 form a group, and magnetic ribs spaced apart from each other are formed between the two permanent magnet slots 5 in each group. That is to say, the two permanent magnet slots 5 in each group are not connected to each other, which further improves the tightness of the permanent magnet and prevents the permanent magnet from loosening or detaching.

[0037] Different from Example 1, Figure 2 As shown, the angle formed between the two permanent magnet slots 5 in a group is 180°. By limiting the degree of the angle between the two permanent magnet slots 5, the opening structure of the rotor punching 4 and the entire core matrix 3 is changed. Specifically, different from Example 1, after changing the angle between the two permanent magnet slots 5 to 180°, the distance of the magnetic isolation bridge of a single permanent magnet slot 5 remains unchanged, and the magnetic ribs between the two permanent magnet slots 5 remain unchanged, and then the length of the single permanent magnet slot 5 changes, thereby ensuring the consistency of motor performance as much as possible. In actual work, the motor whistles less with this setting, which is beneficial to the improvement of the NVH engineering of the whole vehicle. It can be understood that NVH is the abbreviation of noise, vibration and harshness.

[0038] However, on this basis, the strength of this embodiment against stress deformation becomes lower, especially the radial stress of the rotor body 1. Therefore, in order to increase the stability of the structure, support ribs 14 are processed in the weight-reducing hole 8 of this embodiment. The support ribs 14 are located at one-half of the weight-reducing hole 8 and overlap with the radial extension line of the transmission shaft 2. The radial stress of the rotor body 1 is resisted by the support ribs 14.

[0039] The present application discloses a permanent magnet motor rotor, which is lightweight while reducing magnetic leakage through the hole design of the rotor punching sheet 4. The permanent magnet slots 5 are extended and the transition connection is limited to provide innovative structural support for the permanent magnets, further improving the tightness of the permanent magnets and ensuring the quality of the motor rotor. On the premise of making the magnetic isolation bridge thin, the structural deformation is effectively prevented, and the magnetic isolation bridges of the permanent magnet slots set at different angles are of consistent thickness, thereby enhancing the consistency of the motor performance.

[0040] The above-mentioned implementation manner is not a limitation of the present invention, and the present invention is not limited to the above-mentioned examples. Any changes, modifications, additions or substitutions made by technicians in this technical field within the scope of the technical solution of the present invention also fall within the scope of protection of the present invention.

Claims

1. A permanent magnet motor rotor, characterized in that: The invention comprises a rotor body (1), wherein the rotor body (1) forms an iron core base (3) with a circular outer ring, the iron core base (3) comprises a plurality of rotor punchings (4) formed by pressing, a transmission shaft (2) is arranged on the central axis of the iron core base (3), a plurality of weight-reducing holes (8) arranged around the axis of the iron core base (3) are provided on the iron core base (3), a group of heat dissipation holes are provided between any two adjacent weight-reducing holes (8), and a group of permanent magnet slots (5) are also provided on the iron core base (3), the slot edges of each group of permanent magnet slots (5) being away from each other extend toward the magnetic isolation bridge (6) to form an anti-demagnetization extension slot (9), a magnetic steel step (7) is provided between the permanent magnet slot (5) and its anti-demagnetization extension slot (9), and the magnetic steel step (7) is implemented in a manner of limiting and clamping the permanent magnet.

2. The permanent magnet motor rotor according to claim 1, characterized in that: The rotor body (1) rotates around a transmission shaft (2) relative to an external stator winding.

3. The permanent magnet motor rotor according to claim 1, characterized in that: A plurality of the weight-reducing holes (8) are opened around the transmission shaft (2) in a circular array, the intervals between any two adjacent weight-reducing holes (8) are the same, the weight-reducing holes (8) are pentagonal, and the corners between any two adjacent sides of the weight-reducing holes (8) are rounded.

4. The permanent magnet motor rotor according to claim 3, characterized in that: The two permanent magnet slots (5) facing the outer ring of the weight-reducing hole (8) form a group, and magnetic ribs spaced apart from each other are formed between the two permanent magnet slots (5) in each group.

5. The permanent magnet motor rotor according to claim 4, characterized in that: The angle formed between the two permanent magnet slots (5) in a group is 160°-180°.

6. The permanent magnet motor rotor according to claim 1, characterized in that: The edge of the anti-demagnetization extension groove (9) is in the form of an arc segment (10).

7. The permanent magnet motor rotor according to claim 1, characterized in that: Each group of heat dissipation holes comprises a first heat dissipation hole (12) and a second heat dissipation hole (13) spaced apart from each other. The first heat dissipation hole (12) and the second heat dissipation hole (13) are both circular holes, and the second heat dissipation hole (13) is implemented in a manner closer to the transmission shaft (2).

8. The permanent magnet motor rotor according to claim 7, characterized in that: The outer ring of the first heat dissipation hole (12) is provided with oil circulation holes (11), and the number of the oil circulation holes (11) corresponds to the number of groups of heat dissipation holes.

9. The permanent magnet motor rotor according to claim 1, characterized in that: A support rib (14) is machined in the lightening hole (8), and the support rib (14) is located at one-half of the lightening hole (8) and overlaps with the radial extension line of the transmission shaft (2).

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