An electric machine rotor

Abstract

The application discloses a motor rotor core and a motor rotor, and relates to the technical field of motors. The motor rotor core is formed by stacking a plurality of rotor core punching sheets. The rotor core punching sheets include first rotor core punching sheets and second rotor core punching sheets. The first rotor core punching sheets are arranged at the end portions of the rotor core, and the inner diameter of the first rotor core punching sheets is larger than that of the second rotor core punching sheets. When the rotor core is sleeved on a motor shaft, the second rotor core punching sheets are in interference fit with the motor shaft, and the first rotor core punching sheets at the end portions are not in interference fit with the motor shaft, so that the adverse effects of the flanging of the inner diameter of the end portion core and the bowl-shaped deformation of the baffle are avoided. The assembly gap of the rotor is improved, and the rigidity of the rotor is improved without increasing the size, weight and cost of the baffle and the interference ring.

Description

Technical Field

[0001] This invention relates to the field of motor technology, specifically to a motor rotor. Background Technology

[0002] Currently, permanent magnet synchronous motors are widely used in the drive motors and generators of new energy vehicles. The rotor of a permanent magnet synchronous motor typically consists of a motor shaft and a rotor core that is fitted onto the motor shaft with an interference fit. Each stack of rotor cores is made up of multiple rotor core laminations.

[0003] During rotor assembly, factors such as unevenness of the rotor core end faces, localized flanging of the core inner diameter caused by interference fit between the rotor core and motor shaft, and bowl-shaped deformation of the rotor baffle under stress can easily lead to assembly gaps between stacked rotor cores and between the rotor core and rotor baffle. The larger the ratio of the rotor core's outer diameter to its inner diameter, the more pronounced these assembly gaps become. These gaps not only reduce the rotor's stiffness and damping, worsening the motor's NVH performance, but also decrease the working strength and service life of the rotor core, and affect the rotor's appearance quality.

[0004] Existing technologies typically reduce the aforementioned assembly gap by increasing the thickness of the rotor baffle or increasing the clamping force between the rotor baffle and the rotor core. However, this increases the size and weight of the rotor baffle and interference ring, thereby increasing the manufacturing cost of the motor rotor. Summary of the Invention

[0005] The purpose of this invention is to provide an electric motor rotor to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a motor rotor core, comprising a rotor core, wherein the rotor core is formed by stacking multiple rotor core laminations, the rotor core laminations including a first type of rotor core lamination and a second type of rotor core lamination, the first type of rotor core lamination being disposed at the end of the rotor core, and the inner diameter of the first type of rotor core lamination being larger than the inner diameter of the second type of rotor core lamination.

[0007] Preferably, the first type of rotor core lamination is disposed at one or both axial ends of the rotor core, and the first type of rotor core lamination at each axial end is one or more laminations.

[0008] Preferably, the number of the first type of rotor core laminations is positively correlated with the ratio of the outer diameter of the motor rotor core to the inner diameter of the second type of rotor core laminations.

[0009] Preferably, the first type of rotor core lamination and the second type of rotor core lamination are provided with a plurality of weight-removing holes.

[0010] Preferably, the first type of rotor core lamination and the second type of rotor core lamination have axial fastening structures, which are located between two adjacent weight-removing holes.

[0011] Preferably, the axial fastening structure is a snap point or a rivet point.

[0012] Preferably, the rotor core laminations of two adjacent stacks are staggered by a preset angle along the circumference.

[0013] The present invention also provides a motor rotor, including a motor shaft and at least one stack of motor rotor cores as described above, which are mounted on the motor shaft. The second type of rotor core laminations are fixedly connected to the motor shaft, while the first type of rotor core laminations are not fixedly connected to the motor shaft.

[0014] Preferably, the motor shaft is provided with a pair of baffles, which are located on both sides of the rotor core.

[0015] Preferably, each baffle has an interference ring on the side away from the rotor core.

[0016] This invention addresses this issue by using a first type of rotor core lamination with a larger inner diameter at the ends of the rotor core and a second type with a smaller inner diameter for the remaining portion. This prevents the first type of rotor core lamination at the ends from having an interference fit with the motor shaft, thus avoiding localized flanging of the inner diameter caused by the interference fit. It also reduces the press-fit stress on the end core and the adverse effects of the rotor baffle's cup-shaped deformation. Therefore, without increasing the size, weight, or manufacturing cost of the rotor baffle and interference ring, this invention improves the assembly clearance between the stacked rotor cores and between the rotor core and the rotor baffle, enhancing the working strength and appearance quality of the rotor core. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a front view of the overall structure of the present invention; Figure 3 This is a front view of the overall structure of the present invention after the baffle is removed; Figure 4 This is a cross-sectional view at point AA of the present invention; Figure 5 This is an enlarged view of point A in the present invention; Figure 6 This is an enlarged view of section B of the present invention.

[0018] In the diagram: 1. Motor shaft; 2. Rotor core; 3. Rotor core lamination; 4. First type of rotor core lamination; 5. Second type of rotor core lamination; 6. Weight removal hole; 7. Axial fastening structure; 8. Baffle; 9. Interference ring. Detailed Implementation

[0019] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that the orientation or positional relationship indicated by terms such as "inner diameter," "end," "axial direction," and "circumferential direction" used in this invention are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as a limitation of the invention.

[0021] Example This invention provides a motor rotor core, including a rotor core 2, which is formed by stacking multiple rotor core laminations 3 axially. The rotor core laminations 3 include a first type of rotor core lamination 4 and a second type of rotor core lamination 5. The first type of rotor core lamination 4 is disposed at the axial end of the rotor core 2, and the second type of rotor core lamination 5 constitutes the remaining part of the rotor core 2. The inner diameter of the first type of rotor core lamination 4 is larger than the inner diameter of the second type of rotor core lamination 5.

[0022] Specifically, the first type of rotor core lamination 4 can be disposed at one axial end of the rotor core 2, or simultaneously at both axial ends of the rotor core 2; each axial end can have one or more first type of rotor core lamination 4. The number of first type of rotor core lamination 4 can be adjusted according to the ratio of the outer diameter of the rotor core 2 to the inner diameter of the second type of rotor core lamination 5. When this ratio increases, the number of first type of rotor core lamination 4 can be appropriately increased. Its inner hole can be a full circle or a non-full circle (e.g., a circle with a partial notch), and there are no special restrictions on the specific shape of the inner hole.

[0023] In some embodiments, the axial thickness of the first rotor core lamination 4 can be about 0.2 mm, or it can be set to about 0.15 mm or other thicknesses depending on the processing technology and structural requirements. The present invention does not limit this.

[0024] It should be noted that the accompanying drawings are only for illustrative purposes to show the structural relationships of the present invention, and the dimensional proportions between the components do not represent the dimensional proportions in the actual product. The thickness of the first type of rotor core lamination 4 in the actual product may be smaller than the thickness shown in the accompanying drawings, and its specific dimensions can be adjusted according to actual needs.

[0025] In this embodiment, the first type of rotor core lamination 4 is located at the axial end of the rotor core 2. By increasing the inner diameter of the first type of rotor core lamination 4, a clearance space is formed between the first type of rotor core lamination 4 and the motor shaft 1, so that the stress generated by the interference fit of the motor shaft 1 is mainly borne by the second type of rotor core lamination 5, reducing the stress concentration at the end of the rotor core 2 and improving the overall structural stability of the rotor.

[0026] In some embodiments, the first type of rotor core lamination 4 and the second type of rotor core lamination 5 are provided with a plurality of weight-reducing holes 6 to reduce the weight of the rotor core 2. The first type of rotor core lamination 4 and the second type of rotor core lamination 5 are also provided with an axial fastening structure 7, through which multiple rotor core laminations 3 are stacked and fixed together axially. The axial fastening structure 7 is used to connect and fix adjacent rotor core laminations 3 together, and can be a snap point or a rivet point, etc.; taking a snap point as an example, a protrusion and a corresponding recess are stamped on the rotor core lamination 3. When stacking, the protrusions of two adjacent rotor core laminations 3 are embedded into the recesses and interlocked, thereby connecting multiple rotor core laminations 3 into one piece.

[0027] The location of the axial fastening structure 7 is not limited. It can be located between two adjacent weight removal holes 6, between the weight removal hole 6 and the inner hole of the rotor core lamination 3, between the weight removal hole 6 and the outer edge of the rotor core lamination 3, or in other physical areas on the rotor core lamination 3. The number and distribution of the axial fastening structure 7 can be determined according to actual needs.

[0028] In some embodiments, the rotor core 2 comprises multiple stacks arranged axially, with adjacent stacks of rotor core laminations 3 staggered circumferentially by a predetermined angle to form a segmented skewed pole structure. This predetermined angle can be determined based on the number of rotor poles and stator slots of the motor, typically such that the total angle of the staggered stacks of rotor cores 2 corresponds to one cogging torque cycle. Through segmented skewed poles, the cogging torque and torque pulsation generated by each stack of rotor cores 2 are staggered axially and cancel each other out, thereby reducing the motor's cogging torque and torque pulsation, lowering the resulting electromagnetic vibration and noise, and improving the motor's NVH performance.

[0029] This invention also provides a motor rotor, including a motor shaft 1 and at least one stack of the aforementioned motor rotor cores mounted on the motor shaft 1. The second type of rotor core lamination 5 is interference-fitted with the motor shaft 1, and the inner diameter of the first type of rotor core lamination 4 is larger than the outer diameter of the corresponding position on the motor shaft 1, creating a gap between the first type of rotor core lamination 4 and the motor shaft 1, i.e., the first type of rotor core lamination 4 is not interference-fitted with the motor shaft 1.

[0030] Since the first type of rotor core lamination 4 located at the end of the rotor core 2 does not have an interference fit with the motor shaft 1, the end core is prevented from having a local flange in the inner diameter during the pressing process, and the pressing stress of the end core is reduced.

[0031] At the same time, it can reduce the adverse effects of the unevenness of the end face of the rotor core 2 and the bowl-shaped deformation of the baffle 8 after being subjected to force on the end core, and improve the assembly clearance between each stack of rotor cores 2 and between the rotor core 2 and the baffle 8.

[0032] Therefore, without increasing the size, weight, and manufacturing cost of the baffle 8 and interference ring 9, the stiffness, damping, and NVH performance of the rotor are improved, and the working strength, service life, and appearance quality of the rotor core 2 are enhanced.

[0033] Furthermore, a pair of baffles 8 are provided on the motor shaft 1. The pair of baffles 8 are respectively set on both sides of the rotor core 2 for axial limiting of the rotor core 2. An interference ring 9 is provided on the side of each baffle 8 away from the rotor core 2. The interference ring 9 is interference connected to the motor shaft 1 for axial pressing and fixing of the baffle 8.

[0034] It should be noted that this invention is applicable not only to motor rotors with baffles 8, but also to motor rotors without baffles 8; not only to motor rotors including multiple stacks of rotor cores 2, but also to motor rotors including only one stack of rotor cores 2; not only to permanent magnet motor rotors, but also to wound-rotor and squirrel-cage motor rotors. The rotor core laminations 3 are not limited to silicon steel sheets, but can also be other soft magnetic materials such as low-carbon steel sheets, and are not limited by specific material types.

[0035] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A motor rotor core, characterized in that: The rotor core includes a rotor core, which is formed by stacking multiple rotor core laminations. The rotor core laminations include a first type of rotor core lamination and a second type of rotor core lamination. The first type of rotor core lamination is disposed at the end of the rotor core, and the inner diameter of the first type of rotor core lamination is larger than the inner diameter of the second type of rotor core lamination.

2. The motor rotor core according to claim 1, characterized in that: The first type of rotor core lamination is disposed at one or both axial ends of the rotor core, and the first type of rotor core lamination at each axial end is one or more laminations.

3. The motor rotor core according to claim 1, characterized in that: The number of the first type of rotor core laminations is positively correlated with the ratio of the outer diameter of the motor rotor core to the inner diameter of the second type of rotor core laminations.

4. The motor rotor core according to claim 1, characterized in that: The first type of rotor core lamination and the second type of rotor core lamination are provided with several weight-removing holes.

5. The motor rotor core according to claim 4, characterized in that: The first type of rotor core lamination and the second type of rotor core lamination have axial fastening structures, which are located between two adjacent weight-removing holes.

6. The motor rotor core according to claim 4, characterized in that: The axial fastening structure is a snap point or a rivet point.

7. The motor rotor core according to claim 1, characterized in that: The rotor core laminations of two adjacent stacks are staggered by a preset angle along the circumference.

8. A motor rotor, characterized in that: It includes a motor shaft and at least one stack of motor rotor cores as described in any one of claims 1-6, wherein the second type of rotor core laminations are fixedly connected to the motor shaft, and the first type of rotor core laminations are not fixedly connected to the motor shaft.

9. The motor rotor according to claim 7, characterized in that: The motor shaft is provided with a pair of baffles, which are located on both sides of the rotor core.

10. The motor rotor according to claim 8, characterized in that: Each baffle has an interference ring on the side away from the rotor core.

Images