Motor rotor and motor

Abstract

The present application provides a motor rotor, comprising: a rotor lamination (1) provided with a magnet mounting hole group (12), wherein the magnet mounting hole group (12) comprises a plurality of magnet mounting holes (13); and magnets (2) mounted in the magnet mounting holes (13), wherein magnetic isolation holes (14) are formed in two ends of each magnet mounting hole (13), respectively, at least some of the magnetic isolation holes (14) are provided with cantilevers (16), each cantilever (16) extends out of a lamination body of the rotor lamination (1) into the corresponding magnetic isolation hole (14), one end of the cantilever (16) is connected to the lamination body, the other end of the cantilever (16) is spaced apart from the inner wall of the magnetic isolation hole (14), and when the motor rotor rotates, the cantilever (16) is deformed by centrifugal force, so that the other end of the cantilever (16) gets close to or is in contact with the inner wall of the magnetic isolation hole (14), so as to form an auxiliary magnetic flux leakage path (F3). Also provided is a motor comprising the motor rotor.

Description

Motor rotor and motor Technical Field

[0001] The present application relates to a power system of an electric vehicle, and in particular to a motor rotor and a motor. Background Art

[0002] In electric vehicles, permanent magnet synchronous motors (PMSMs) are key power components. The magnets in their rotors provide lossless excitation flux, making the motor rotor crucial to its design.

[0003] Patent CN104659996A discloses a magnetic flux leakage type mechanical variable flux permanent magnet synchronous motor, which uses the force change of the cam to make the magnetic adjustment block rotate a certain angle relative to the motor rotor, thereby changing the air gap length between the magnetic adjustment block and the stator and adjusting the magnetic flux leakage resistance of the motor.

[0004] However, the above technical solution has the following disadvantages.

[0005] (1) In order to adjust the leakage magnetic reluctance, an additional mechanical adjustment structure is required, which not only takes up space and makes the motor larger, but also increases the complexity and cost of the motor structure.

[0006] (2) This structure is only applicable to permanent magnet synchronous motors with outer rotor and inner stator, and cannot be used for permanent magnet synchronous motors with inner rotor and outer stator.

[0007] Summary of the Invention

[0008] The purpose of this application is to overcome or at least alleviate the above-mentioned deficiencies in the prior art and to provide a motor rotor whose magnetic bridge width can vary with the speed of the motor. The embodiments of this application also provide a motor including the motor rotor.

[0009] An embodiment of the present application provides a motor rotor, comprising:

[0010] The rotor laminations are provided with a magnet mounting hole group, wherein the magnet mounting hole group includes a plurality of magnet mounting holes,

[0011] A magnet is mounted in the magnet mounting hole, and magnetic isolation holes are formed at both ends of the magnet mounting hole. At least part of the magnetic isolation holes is provided with a cantilever, and the cantilever extends from the lamination body of the rotor lamination into the magnetic isolation hole. One end of the cantilever is connected to the lamination body, and the other end of the cantilever is spaced apart from the inner wall of the magnetic isolation hole.

[0012] When the motor rotor rotates, the cantilever is deformed by the centrifugal force, so that the other end of the cantilever can approach or contact the inner wall of the magnetic isolation hole, thereby forming an auxiliary magnetic leakage path.

[0013] In at least one possible embodiment, the cantilever is arc-shaped, and the arc is convex toward the radial inner side of the rotor lamination.

[0014] In at least one possible embodiment, the cantilever and the rotor lamination body are formed integrally.

[0015] In at least one possible embodiment, the magnet mounting hole group includes one or more V-shaped holes, and the cantilever extends from two circumferential ends of the V-shaped hole to a circumferential middle position.

[0016] In at least one possible implementation manner, the one end of the cantilever is located radially inward of the other end of the cantilever.

[0017] In at least one possible embodiment, the contour shape of the other end of the cantilever is the same as the contour shape of the inner wall of the area of ​​the magnetic isolation hole corresponding to the other end of the cantilever, so that the cantilever can fit the inner wall of the magnetic isolation hole after deformation.

[0018] In at least one possible implementation manner, at least part of the two magnetic isolation holes at both ends of the magnet are both provided with the cantilever.

[0019] In at least one possible embodiment, the magnet mounting hole group includes one or more V-shaped holes.

[0020] A first magnetic bridge is formed between the magnetic isolation holes at both ends of the V-shaped hole and the outer edge of the rotor lamination, and the path of the leakage magnetic flux passes through the first magnetic bridge.

[0021] A second magnetic bridge is formed between the two magnetic isolation holes at the turning point of the V-shaped hole, and the leakage magnetic flux path passes through the second magnetic bridge.

[0022] For the cantilever near the first magnetic bridge, the cantilever at least includes a portion extending along the circumference of the rotor lamination.

[0023] Regarding the cantilever near the second magnetic bridge, the cantilever at least includes a portion extending in the radial direction of the rotor lamination.

[0024] In at least one possible implementation manner, the magnetic isolation hole and the magnet mounting hole are integrally formed and communicated with each other.

[0025] An embodiment of the present application further provides a motor, which includes the motor rotor described in any one of the above technical solutions.

[0026] Through the above embodiments, the present application can obtain at least one of the following beneficial effects.

[0027] (1) The width of the rotor laminations' magnetic bridge can vary with the motor's speed. At low speeds, the bridge width is narrower, the main magnetic flux is larger, and a higher torque can be output. At high speeds, the bridge width is wider, the main magnetic flux is smaller, and the motor can run at high speeds under limited DC voltage. By adjusting the motor speed, the main magnetic flux can be easily adjusted, thereby optimizing the motor's performance.

[0028] (2) The shape of the other end of the cantilever enables the cantilever to fit as closely as possible to the magnetic isolation hole after deformation, and the air gap can be smaller.

[0029] (3) The cantilever and the laminated body are formed in one piece, which neither adds additional equipment or manufacturing costs nor increases the complexity of motor control and manufacturing. It is easy to manufacture and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 shows a schematic structural diagram of a possible motor rotor.

[0031] FIG2 shows a partially enlarged view of FIG1 .

[0032] FIG3 shows a partially enlarged view of a motor rotor according to an embodiment of the present application.

[0033] FIG4 shows a schematic structural diagram of a cantilever of a motor rotor in an undeformed state according to an embodiment of the present application.

[0034] FIG5 is a schematic structural diagram showing a cantilever deformation state of a motor rotor according to an embodiment of the present application.

[0035] FIG. 6 shows a partially enlarged view of FIG. 3 .

[0036] 7A is a color diagram showing a partially enlarged schematic diagram of a magnetic flux simulation of a cantilever of a motor rotor in an undeformed state according to an embodiment of the present application.

[0037] FIG7B is a color diagram showing a partially enlarged schematic diagram of a magnetic flux simulation of a cantilever deformation state of a motor rotor according to an embodiment of the present application.

[0038] FIG8A is a partially enlarged schematic black-and-white diagram illustrating a magnetic flux simulation of a cantilever of a motor rotor in an undeformed state according to an embodiment of the present application.

[0039] FIG8B is a black and white diagram showing a partially enlarged schematic diagram of a magnetic flux simulation of a cantilever deformation state of a motor rotor according to an embodiment of the present application. DETAILED DESCRIPTION

[0040] As shown in Figures 1 and 2 , the magnets 2 in a possible motor rotor 100 can be arranged in a "V" shape, a common design. One or more layers of magnets 2 can be radially arranged. Two magnets 2 can form a V-shape, with magnetic isolation holes 14 formed at each end of each magnet 2. A first magnetic bridge 15A can be formed between the magnetic isolation holes 14 and the outer edge of the rotor lamination 1, and a second magnetic bridge 15B can be formed between the two magnetic isolation holes 14.

[0041] Magnet 2 provides the main magnetic flux F1, which can pass through the air gap to the stator teeth and yoke, then return to the motor rotor from the adjacent magnetic poles through the air gap, ultimately forming a magnetic flux loop. In addition to the main magnetic flux F1, there is also a lot of magnetic flux that does not pass through the stator or winding conductors. This is usually called leakage flux F2.

[0042] Because this leakage flux F2 does not participate in energy conversion with the current passing through the winding, it does not contribute to the output torque. However, leakage flux F2 is not always detrimental to the operation of permanent magnet synchronous motors, especially those operating over a wide speed range, such as the drive motors in electric vehicles.

[0043] Permanent magnet synchronous motors generate a large back EMF when running at high speeds. Field-weakening control mode is typically used to suppress this back EMF, thereby achieving high-speed operation. The back EMF generated by magnet 2 is proportional to the motor speed. At high motor speeds, the back EMF may exceed the maximum allowable voltage, such as the maximum voltage of a battery. Without this voltage difference, current cannot flow, and the motor will not output torque.

[0044] When the motor is running in flux weakening control mode, leakage flux F2 is undoubtedly helpful. As mentioned earlier, magnet 2 has the ability to generate magnetic flux and back electromotive force, which requires a large d-axis current (Id, or demagnetization current) to suppress the magnetic flux so that the motor can run at high speed under limited DC voltage.

[0045] Based on the above analysis, there are two conflicting requirements for the leakage flux F2. When the motor is running at low speed, it is desirable to narrow the magnetic bridge to reduce the leakage flux and increase the torque. When the motor is running at high speed, it is desirable to widen the magnetic bridge to allow more leakage flux to pass through, thereby effectively weakening the main magnetic flux.

[0046] Exemplary embodiments of the present application are described below with reference to the accompanying drawings.

[0047] 3 to 6 , an embodiment of the present application provides a permanent magnet synchronous motor, which includes a motor rotor and a motor stator. The motor stator can be arranged radially outside the motor rotor, that is, the motor is an outer-stator-inner-rotor motor.

[0048] The motor rotor (variable magnet bridge permanent magnet motor rotor) 100 includes a rotor lamination 1 and a magnet 2. A rotor shaft hole 11 may be provided at the center of the rotor lamination 1.

[0049] The rotor lamination 1 is also provided with a magnet mounting hole group 12 for mounting the magnet 2. Multiple groups of magnet mounting hole groups 12 can be provided along the circumferential direction C of the rotor lamination 1. Multiple groups of magnet mounting hole groups 12 are arranged around the rotor shaft hole 11. For example, 8 groups of magnet mounting hole groups 12 can be provided.

[0050] The magnet mounting hole group 12 may include a plurality of magnet mounting holes 13, each of which may accommodate one or more magnets 2. Optionally, the magnet mounting hole group 12 may form one or more V-shaped holes, wherein the two magnet mounting holes 13 constituting the V-shaped hole may be independent of each other, and the turning point of the V-shaped hole may point radially inward.

[0051] In this embodiment, the magnet mounting hole group 12 may include four magnet mounting holes 13. The four magnet mounting holes 13 may form two V-shaped holes of different sizes, wherein the smaller V-shaped hole may be located radially outside the larger V-shaped hole.

[0052] When viewed along the axial direction of the motor rotor 100, the length of the magnet mounting hole 13 is greater than the length of the magnet 2, and magnetic isolation holes 14 are formed at both ends of the magnet 2. The magnetic isolation holes 14 can be integrally formed with and connected to the magnet mounting hole 13. The magnetic isolation holes 14 can have an irregular shape that is approximately circular or elliptical. The magnetic isolation holes 14 can prevent magnetic flux leakage and improve the torque of the motor.

[0053] A first magnetic bridge 15A can be formed between the magnetic isolation holes 14 at both ends of the V-shaped hole and the outer edge of the rotor lamination 1 , and a second magnetic bridge 15B can be formed between the two magnetic isolation holes 14 at the turning point of the V-shaped hole.

[0054] The path of leakage magnetic flux F2 passes through first magnetic bridge 15A and second magnetic bridge 15B. The wider the magnetic bridges (including first magnetic bridge 15A and second magnetic bridge 15B), the more leakage magnetic flux F2 will pass through the bridges, which tends to weaken main magnetic flux F1. Based on the path of leakage magnetic flux F2, the width of first magnetic bridge 15A refers to the dimension of first magnetic bridge 15A in a direction perpendicular to the path of leakage magnetic flux F2 passing through first magnetic bridge 15A, that is, the dimension of first magnetic bridge 15A generally along the radial direction of the rotor laminations. The width of second magnetic bridge 15B refers to the dimension of second magnetic bridge 15B in a direction perpendicular to the path of leakage magnetic flux F2 passing through second magnetic bridge 15B, that is, the dimension of second magnetic bridge 15B generally along the circumferential direction of the rotor laminations.

[0055] The two magnetic isolation holes 14 at either end of the magnet 2 are each provided with a cantilever 16. One end of the cantilever 16 is connected to the inner wall of the magnetic isolation hole 14 (the lamination body of the rotor lamination 1), and the other end of the cantilever 16 is spaced apart from the magnetic isolation hole 14. Here, the cantilever 16 can be described as extending from the lamination body of the rotor lamination 1 into the magnetic isolation hole 14. When the motor rotor rotates at high speed, the cantilever 16 can deform under the action of centrifugal force, and the other end of the cantilever 16 can approach or contact the inner wall of the magnetic isolation hole 14, and the air gap between the cantilever 16 and the magnetic pole becomes smaller and smaller. The cantilever 16 can form an auxiliary leakage magnetic path F3. The leakage magnetic flux F2 can pass through this auxiliary leakage magnetic path F3 of the cantilever 16, thereby increasing the leakage magnetic flux and weakening the main magnetic flux F1. The magnetic path formed by the cantilever 16 can help reduce the d-axis current (Id, also known as the demagnetization current), allowing the motor to operate at high speed under limited DC voltage.

[0056] The cantilever 16 and the lamination body may be formed integrally. The cantilever 16 is formed integrally when the rotor lamination 1 is manufactured by, for example, stamping, which is convenient to manufacture and has low cost.

[0057] As shown in Figure 6, the cantilever 16 can be arc-shaped and can protrude radially inward of the rotor laminations. The cantilever 16 can cause the auxiliary leakage flux path F3 and the leakage flux F2 to be approximately parallel. For the cantilever 16 near the first magnetic bridge 15A, the cantilever 16 includes at least a portion extending generally circumferentially, thereby increasing the radial width of the first magnetic bridge 15A. For the cantilever 16 near the second magnetic bridge 15B, the cantilever 16 includes at least a portion extending generally radially, thereby increasing the circumferential width of the second magnetic bridge 15B.

[0058] The cantilever 16 may extend from both circumferential ends of the V-shaped hole toward the circumferential center. One end of the cantilever 16 connected to the inner wall of the magnetic isolation hole 14 (which may be referred to as the base end) may (but is not necessarily) be located radially inward of the other end of the cantilever 16 (which may be referred to as the free end) spaced apart from the inner wall of the magnetic isolation hole 14.

[0059] The contour shape of the other end of the cantilever 16 can be the same (including approximately the same) as the inner wall contour shape of the area corresponding to the magnetic isolation hole 14 and the other end of the cantilever 16, so that the cantilever 16 can fit as closely as possible to the inner wall of the magnetic isolation hole 14 after deformation, and the air gap can be smaller.

[0060] As shown in Figure 4, when the motor rotor speed is low, cantilever 16 does not deform or deforms only slightly, and the air gap between cantilever 16 and the magnetic pole is large. Leakage flux F2 passes through the rotor laminations 1 (first magnetic bridge 15A and second magnetic bridge 15B) surrounding magnetic isolation hole 14. The path of leakage flux F2 surrounds magnetic isolation hole 14, and cantilever 16 forms no magnetic flux path or a magnetic flux path with low flux. Leakage flux path F2 easily reaches saturation, which can reduce leakage flux F2 and improve motor torque.

[0061] As shown in Figure 5, when the motor rotor speed is high, the centrifugal force acting on cantilever 16 is greater, causing cantilever 16 to deform significantly or the other end of cantilever 16 to contact the inner wall of magnetic isolation hole 14, reducing the air gap between cantilever 16 and the magnetic pole. Cantilever 16 forms an auxiliary magnetic leakage path F3, allowing some magnetic flux to leak through cantilever 16. The magnetic bridge of the total leakage magnetic flux (including leakage magnetic flux F2 and auxiliary magnetic leakage path F3) widens, allowing more magnetic flux to leak. This makes the magnetic bridge less likely to reach saturation, effectively weakening the main magnetic flux F1 and reducing the impact of the back electromotive force.

[0062] 7A and 7B , the color diagram uses colors to represent the magnitude of the magnetic flux, and changes in red, orange, yellow, green, cyan, blue, and purple indicate that the magnetic flux gradually decreases.

[0063] As shown in FIG7A , when the air gap between the cantilever 16 and the magnetic pole is large, the leakage flux passes more through the second magnetic bridge 15B and less through the cantilever 16 . The second magnetic bridge 15B is easily saturated, so the leakage flux F2 is small.

[0064] As shown in FIG7B , when the air gap between cantilever 16 and the magnetic pole is small, some leakage flux can pass through cantilever 16 in addition to second magnetic bridge 15B. This leakage flux is relatively evenly distributed across second magnetic bridge 15B and cantilever 16. This is equivalent to widening the magnetic bridge for the total leakage flux, allowing more flux to leak. The magnetic bridge for the leakage flux is less likely to reach saturation, allowing the leakage flux to be larger, effectively weakening the main magnetic flux F1 and reducing the impact of the back EMF.

[0065] As shown in Figure 8A , when the air gap between cantilever 16 and the magnetic pole is large, leakage flux flows more through second magnetic bridge 15B and less through cantilever 16, making second magnetic bridge 15B more likely to reach saturation. Consequently, leakage flux F2 is small. The black-and-white image (or grayscale image) in Figure 8A shows that the free end of cantilever 16 is lighter (whiter) than the gap between the free end of cantilever 16 and the inner wall of magnetic isolation hole 14, indicating that less leakage flux flows through this gap.

[0066] As shown in FIG8B , when the air gap between cantilever 16 and the magnetic pole is small, some leakage flux can pass through cantilever 16 in addition to second magnetic bridge 15B. This leakage flux is relatively evenly distributed across second magnetic bridge 15B and cantilever 16. This is equivalent to widening the magnetic bridge for the total leakage flux, allowing more flux to leak. The magnetic bridge for the leakage flux is less likely to reach saturation, allowing the leakage flux to be larger, effectively weakening the main magnetic flux F1 and reducing the impact of the back EMF.

[0067] The black-and-white image (or grayscale image) of FIG8B shows that the gap between the free end of cantilever 16 and the inner wall of magnetic isolation hole 14 has decreased or even disappeared. This gap appears whiter and brighter than the corresponding position in FIG8A , indicating that more leakage flux passes through this gap. (However, the whitening and brightness of second magnetic bridge 15B does not indicate that more leakage flux passes through this gap than in FIG8A .)

[0068] Of course, the present application is not limited to the above embodiments. Those skilled in the art can make various modifications to the above embodiments of the present application under the guidance of the present application without departing from the scope of the present application.

[0069] (1) In the above embodiment, some of the magnetic isolation holes 14 are provided with cantilevers 16, but the present application is not limited thereto. On the premise of maintaining the strength of the cantilever, each magnetic isolation hole may be provided with a cantilever.

[0070] (2) In the above embodiment, the two magnetic isolation holes 14 at both ends of the magnet 2 are both provided with cantilevers 16, but the present application is not limited thereto. A cantilever may be provided in the magnetic isolation hole at one end of the magnet.

[0071] (3) In the above embodiment, one cantilever 16 is provided in one magnetic isolation hole 14 . However, the present application is not limited thereto. More cantilevers may be provided in one magnetic isolation hole.

[0072] (4) It is understood that the specific structures such as the extension direction of the cantilever and the position of the connection to the magnetic isolation hole can be designed according to the required rotor topology and operating conditions.

[0073] (5) The rotor lamination has a wide range of applications. In addition to the above-mentioned specific embodiments, other motor rotors with magnets and magnetic bridges inside can use the rotor lamination.

[0074] (6) The rotor laminations (excluding magnets) may be a subject of this application.

[0075] For example, a vehicle power system of an electric bridge drive system can be a subject of the present application. The vehicle power system can include a motor and a speed change mechanism.

[0076] The rotor laminations, motor rotor (variable magnetic bridge permanent magnet motor rotor) and motor of the present application can achieve the following beneficial effects.

[0077] (1) The width of the rotor laminations' magnetic bridge can vary with the motor's speed. At lower speeds, the bridge width is narrower, the main magnetic flux is larger, and a higher torque can be output. At higher speeds, the bridge width is wider, the main magnetic flux is smaller, and the motor can operate at high speeds under limited DC voltage. Based on the precise calculation of the relationship between the deformation of the cantilever 16 and the motor speed, the main magnetic flux can be easily adjusted by adjusting the motor speed, thereby optimizing the motor's performance.

[0078] (2) The shape of the other end of the cantilever 16 enables the cantilever 16 to fit as closely as possible to the inner wall of the magnetic isolation hole 14 after deformation, and the air gap can be smaller.

[0079] (3) The cantilever 16 and the laminate body are formed integrally, which neither adds additional equipment or manufacturing costs nor increases the complexity of motor control and manufacturing. The manufacturing is convenient and the cost is low.

[0080] Reference Signs List

[0081] 100 motor rotor

[0082] F1 main magnetic flux F2 leakage magnetic flux F3 auxiliary leakage magnetic flux path

[0083] 1 rotor lamination 11 rotor shaft hole 12 magnet mounting hole group 13 magnet mounting hole 14 magnetic isolation hole 15A first magnetic bridge 15B second magnetic bridge 16 cantilever

[0084] 2 magnets

[0085] C circumferential

Claims

1. A motor rotor, comprising: A rotor lamination (1), the rotor lamination (1) being provided with a magnet mounting hole group (12), the magnet mounting hole group (12) including a plurality of magnet mounting holes (13), Magnets (2), the magnets (2) being mounted in the magnet mounting holes (13), magnetic isolation holes (14) being respectively formed at two ends of the magnet mounting holes (13), at least part of the magnetic isolation holes (14) being provided with cantilevers (16), the cantilevers (16) protruding from the lamination body of the rotor lamination (1) into the magnetic isolation holes (14), one end of the cantilever (16) being connected to the lamination body, and the other end of the cantilever (16) being spaced apart from the inner wall of the magnetic isolation hole (14), When the motor rotor rotates, the cantilever (16) is deformed by centrifugal force, enabling the other end of the cantilever (16) to approach or contact the inner wall of the magnetic isolation hole (14), thereby forming an auxiliary magnetic leakage path (F3).

2. The motor rotor according to claim 1, characterized in that, The cantilever (16) is arc-shaped, and the arc protrudes towards the radially inner side of the rotor lamination (1).

3. The motor rotor according to claim 1, characterized in that, The cantilever (16) and the lamination body of the rotor lamination (1) are integrally formed.

4. The motor rotor according to claim 1, characterized in that, The magnet mounting hole group (12) includes one or more V-shaped holes, and the cantilever (16) extends from the circumferential two ends of the V-shaped hole towards the circumferential middle position.

5. The motor rotor according to claim 1, wherein The one end of the cantilever (16) is located radially inside the other end of the cantilever (16).

6. The motor rotor according to claim 1, wherein The contour shape of the other end of the cantilever (16) is the same as the inner wall contour shape of the region of the magnetic isolation hole (14) corresponding to the other end of the cantilever (16), enabling the cantilever (16) to fit against the inner wall of the magnetic isolation hole (14) after deformation.

7. The motor rotor according to claim 1, characterized in that, The two magnetic isolation holes (14) at both ends of at least part of the magnets (2) are both provided with the cantilevers (16).

8. The motor rotor according to claim 1, characterized in that, The magnet mounting hole group (12) includes one or more V-shaped holes, A first magnetic bridge (15A) is formed between the magnetic isolation holes (14) at both ends of the V-shaped hole and the outer edge of the rotor lamination (1), and the path of the leakage magnetic flux (F2) passes through the first magnetic bridge (15A), A second magnetic bridge (15B) is formed between the two magnetic isolation holes (14) at the turning point of the V-shaped hole, and the path of the leakage magnetic flux (F2) passes through the second magnetic bridge (15B), For the cantilever (16) near the first magnetic bridge (15A), the cantilever (16) at least includes a part extending along the circumferential direction of the rotor lamination (1), For the cantilever (16) near the second magnetic bridge (15B), the cantilever (16) at least includes a part extending along the radial direction of the rotor lamination (1).

9. The motor rotor according to claim 1, wherein The magnetic isolation holes (14) and the magnet mounting holes (13) are integrally formed and communicated.

10. A motor, comprising the motor rotor according to any one of claims 1 to 9.

Images