Motor rotor balanced utilizing rotor laminations, motor and powertrain

Abstract

Provided in the present application are a motor rotor balanced utilizing rotor laminations, a motor and a powertrain. The motor rotor comprises rotor cores and a motor shaft. The rotor cores comprise two first rotor cores and a plurality of second rotor cores, the plurality of second rotor cores being successively arranged between the two first rotor cores in the motor axial direction. Each first rotor core and each second rotor core all comprise a plurality of rotor laminations, each rotor lamination comprising a shaft hole, and an inner circumferential surface of each shaft hole comprising at least one protrusion. In the motor axial direction, the motor shaft penetrates through the shaft hole of each rotor lamination, an outer peripheral surface of the motor shaft comprising at least one keyway, and each protrusion being used for being embedded into one keyway of the motor shaft. Each rotor lamination in each first rotor core comprises at least one balancing through hole. Machining the balancing through holes in the rotor laminations in the first rotor cores not only reduces the amount of unbalance of the motor rotor, but also improves the material removal efficiency for dynamic balance of the motor rotor.

Description

Motor rotor, motor and power assembly balanced by rotor punching

[0001] This application claims priority to the Chinese patent application with application number 202323273785.3 filed with the State Intellectual Property Office of China on November 30, 2023, and priority to the Chinese patent application entitled “Motor rotor, motor and power assembly balancing using rotor punchings”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of motors, and more particularly, to a motor rotor balanced by rotor punchings, a motor, and a power assembly. Background Art

[0003] The motor rotor is a critical component of the motor. Rotor imbalance directly impacts its performance, noise, and lifespan. To reduce rotor imbalance, a double keyway is typically machined into the motor shaft: one keyway transmits torque to the rotor core, and the other keyway is used for balancing. However, keyway machining is expensive, requires high symmetry, and requires error-proofing. This places high demands on the motor shaft's machining precision, increasing the rotor's machining cost.

[0004] Summary of the Invention

[0005] The present application provides a motor rotor, a motor, and a power assembly that utilize rotor punchings for balancing, thereby reducing the imbalance of the motor rotor, lowering the machining accuracy requirements for the motor shaft, and reducing the machining cost of the motor rotor.

[0006] In a first aspect, a motor rotor balanced using rotor punchings is provided. The motor rotor includes a rotor core and a motor shaft. The rotor core includes two first rotor cores and multiple second rotor cores. The multiple second rotor cores are sequentially arranged between the two first rotor cores along the motor axis. Each first rotor core and each second rotor core includes multiple rotor punchings. Each rotor punching includes an axial hole, and the inner circumferential surface of each axial hole includes at least one protrusion. Along the motor axis, the motor shaft passes through the axial hole of each rotor punching. The outer circumferential surface of the motor shaft includes at least one keyway, and each protrusion is configured to engage a keyway of the motor shaft. Each rotor punching in each first rotor core includes at least one balancing through-hole.

[0007] In the motor rotor provided in the embodiments of the present application, balancing holes are machined into each rotor punching in the first rotor core, arranged axially at both ends of the rotor core. This not only reduces the motor rotor's imbalance but also improves the efficiency of de-weighting during dynamic balancing. Furthermore, only one keyway is required on the motor shaft to transmit torque to the rotor core, reducing the machining accuracy requirements and costs for the motor shaft. This, in turn, reduces the machining costs of the motor rotor.

[0008] In one implementation, each rotor lamination in a first rotor core includes multiple weight-reducing through-holes, with at least one balancing through-hole being a weight-reducing through-hole. The multiple weight-reducing through-holes are distributed circumferentially around an axial hole in the rotor lamination. Each weight-reducing through-hole extends axially through the rotor lamination, and at least one of the multiple weight-reducing through-holes has a projected area that is different from that of the other weight-reducing through-holes.

[0009] By modifying the size of at least one weight-reducing through-hole on each rotor lamination in the first rotor core, the motor rotor's imbalance is reduced. This reuses the weight-reducing through-holes on each rotor lamination in the first rotor core, reducing the weight reduction and time required to remove the weight from the motor rotor, and improving the rotor's dynamic balancing efficiency.

[0010] In one implementation, the projected area of ​​at least one weight-reducing through hole along the axial direction of the rotor punching is smaller than the area of ​​other weight-reducing through holes, and the angle between the line connecting at least one weight-reducing through hole and the center of the rotor punching and the line connecting each protrusion and the center of the rotor punching is less than 90 degrees.

[0011] The imbalance of the motor rotor is reduced by increasing the weight on the side where the protrusion of the first rotor core is located, such as reducing the area of ​​the weight-reducing through hole on the side where the protrusion of the first rotor core is located.

[0012] In one implementation, the projected area of ​​at least one weight-reducing through hole along the axial direction of the rotor punching is larger than the area of ​​other weight-reducing through holes, and the angle between the line connecting at least one weight-reducing through hole and the center of the rotor punching and the line connecting each protrusion and the center of the rotor punching is greater than 90 degrees and less than 180 degrees.

[0013] The unbalance of the motor rotor is reduced by removing weight on the side opposite to the protrusion of the first rotor core, such as increasing the area of ​​the weight-reducing through hole on the side opposite to the protrusion of the first rotor core.

[0014] When each rotor lamination of the first rotor core includes two sets of weight-reducing through-holes, the motor rotor imbalance can be reduced by modifying the size of at least one of the weight-reducing through-holes in at least one set. This reuse of at least one of the weight-reducing through-holes in at least one set reduces the weight reduction and time required to remove weight from the motor rotor, thereby improving the dynamic balancing efficiency of the motor rotor.

[0015] In one implementation, each rotor lamination in a first rotor core includes multiple oil passage holes, and at least one trimming hole is an oil passage hole. The multiple oil passage holes are distributed circumferentially around an axial hole in the rotor lamination. Each oil passage hole extends axially through the rotor lamination. The projected area of ​​each oil passage hole is smaller than the projected area of ​​each magnetic steel through hole, and the projected area of ​​at least one of the multiple oil passage holes is different from that of the other oil passage holes.

[0016] By modifying the size of at least one oil passage hole on each rotor lamination in the first rotor core, the motor rotor's imbalance is reduced. This reuse of the oil passage holes in each rotor lamination in the first rotor core reduces the weight loss and time required to deweight the motor rotor, improving the rotor's dynamic balancing efficiency.

[0017] In one implementation, the projected area of ​​at least one oil passage hole along the axial direction of the rotor punch is smaller than the areas of the other oil passage holes, and the angle between the line connecting the at least one oil passage hole and the center of the rotor punch and the line connecting each protrusion and the center of the rotor punch is less than 90 degrees. Alternatively, the projected area of ​​at least one oil passage hole along the axial direction of the rotor punch is larger than the areas of the other oil passage holes, and the angle between the line connecting the at least one oil passage hole and the center of the rotor punch and the line connecting each protrusion and the center of the rotor punch is greater than 90 degrees and less than 180 degrees.

[0018] The imbalance of the motor rotor is reduced by increasing the weight of the side of the first rotor core where the protrusion is located, such as reducing the area of ​​the oil passage hole on the side where the protrusion is located.

[0019] In one implementation, the plurality of oil passage holes include two groups of oil passage holes, each of which is distributed around an axial hole, and at least one group of oil passage holes includes at least one oil passage hole. The distance between one of the two groups of oil passage holes and the center of the rotor punching is greater than the distance between the other group of oil passage holes and the center of the rotor punching.

[0020] When each rotor lamination of the first rotor core includes two sets of oil passage holes, the motor rotor imbalance is reduced by modifying the size of at least one oil passage hole in at least one set of oil passage holes. This reuse of at least one oil passage hole in at least one set of oil passage holes reduces the weight and time required to deweight the motor rotor, thereby improving the dynamic balancing efficiency of the motor rotor.

[0021] In one implementation, each rotor lamination in a first rotor core includes multiple magnetic through-holes. Each magnetic through-hole extends axially through the rotor lamination. Circumferentially, the multiple magnetic through-holes surround an axial hole. In a radial direction, the distance between each weight-reducing through-hole or each oil passage through-hole and the center of the rotor lamination is smaller than the distance between each magnetic through-hole and the center of the rotor lamination.

[0022] By modifying the size of at least one weight-reducing through hole and / or oil channel through hole on each rotor punching in the first rotor core without modifying the size of the magnetic steel through hole, the imbalance of the motor rotor is reduced while improving the magnetic concentration capacity of the magnetic steel.

[0023] In one implementation, along the radial direction of the motor, an angle θ is formed between a line connecting each balancing through hole of each rotor punching in each first rotor core and the center of the rotor punching and a line connecting each protrusion and the center of the rotor punching, and 90°≤θ≤180°.

[0024] The imbalance of the motor rotor is reduced by removing weight from the side opposite to the protrusion of the first rotor core, such as increasing the area of ​​the oil passage hole on the side opposite to the protrusion of the first rotor core.

[0025] In one implementation, each rotor punching in each first rotor core includes multiple balancing through holes, and the multiple balancing through holes are arranged at intervals along the circumference of the rotor punching. The angle between the line connecting one of the two adjacent balancing through holes and the center of the rotor punching and the line connecting the other balancing through hole and the center of the rotor punching is less than 180 degrees.

[0026] By providing multiple balancing holes spaced circumferentially on each rotor sheet in the first rotor core, the imbalance of the motor rotor is reduced. This reduces the weight loss and time required to deweight the motor rotor, and improves the dynamic balancing efficiency of the motor rotor.

[0027] In one implementation, the rotor punching in each first rotor core includes a plurality of balancing through holes, and the plurality of balancing through holes are arranged at intervals along the radial direction of the rotor punching. The angle between the line connecting each balancing through hole and the center of the rotor punching and the line connecting each protrusion and the center of the rotor punching is equal to 180 degrees.

[0028] By providing multiple balancing holes spaced radially along each rotor punching in the first rotor core, the imbalance of the motor rotor is reduced. This reduces the weight loss and time required to deweight the motor rotor, and improves the dynamic balancing efficiency of the motor rotor.

[0029] In one implementation, at least two of the plurality of trim through holes along the axial direction of the motor have different projected areas or projected shapes.

[0030] By providing balancing through holes of different sizes and shapes, the unbalance amount of the motor rotor is reduced, thereby improving the flexibility of adjusting the unbalance amount of the motor rotor.

[0031] In one implementation, along the axial direction of the motor, the projections of each protrusion of the two first rotor cores overlap, and the projections of at least one balancing through hole of a rotor punching in one first rotor core do not overlap with the projections of at least one balancing through hole of a rotor punching in the other first rotor core.

[0032] Balancing through holes with different angles along the circumferential direction or radial direction of the motor are arranged on the rotor punchings of the two first rotor cores, thereby improving the balancing rate of the unbalanced amount of the motor rotor.

[0033] In one implementation, each rotor lamination has one protrusion and one keyway on the motor shaft. The length of the keyway along the motor axis is greater than the length of the rotor core. In the motor's radial direction, the notch of the keyway is aligned with the base of the keyway. This facilitates machining and assembly of the rotor laminations and the motor shaft.

[0034] In a second aspect, a motor is provided. The motor includes a motor stator and a motor rotor as described in any one of the first aspect and possible implementations of the first aspect, wherein the motor rotor is sleeved in a center hole of the motor stator.

[0035] In a third aspect, a power assembly is provided, which includes a reducer and the motor as described in the second aspect, wherein the motor shaft of the motor is drivingly connected to the input shaft of the reducer.

[0036] The technical effects of the second aspect or the third aspect mentioned above can refer to the corresponding description in the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 is a schematic structural diagram of an electric vehicle provided in an embodiment of the present application.

[0038] FIG2 is a schematic diagram of an exploded structure of a motor rotor provided in an embodiment of the present application.

[0039] FIG. 3 is a schematic diagram of a cross section of the motor rotor shown in FIG. 2 .

[0040] FIG. 4 is an enlarged schematic diagram of portion A of the motor rotor shown in FIG. 3 .

[0041] 5 to 13 are schematic structural diagrams of the first rotor core provided in embodiments of the present application. DETAILED DESCRIPTION

[0042] The technical solution in this application will be described below with reference to the accompanying drawings.

[0043] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in this article is merely a way to describe the association relationship of associated objects, indicating that three relationships can exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0044] The terms "upper", "lower", "inside", "outside", etc. in the embodiments of the present application indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present application.

[0045] References to "some embodiments" and the like in this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in some embodiments" and the like that appear in different places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0046] The terms "equal" and "equal to" used in this application are not strictly equal, but rather fall within an acceptable error range. The terms "parallel" and "perpendicular" are not strictly parallel, but rather fall within an acceptable error range. The terms "perpendicular" and "perpendicular" are not strictly perpendicular, but rather fall within an acceptable error range.

[0047] In the embodiments of this application, the same reference numerals represent the same component or part. In the embodiments of this application, for multiple identical parts, only one of the parts may be labeled with a reference numeral in the drawings as an example. The same reference numerals apply to other identical parts or components. In addition, the sizes and dimensions of the parts shown in the drawings are for illustrative purposes only.

[0048] An embodiment of the present application provides a motor rotor that is balanced using rotor punchings. The motor rotor includes a rotor core and a motor shaft. The rotor core includes two first rotor cores and multiple second rotor cores. The multiple second rotor cores are arranged in sequence between the two first rotor cores along the motor axis. Each first rotor core and each second rotor core includes multiple rotor punchings. Each rotor punching includes an axial hole, and the inner circumference of each axial hole includes at least one protrusion. Along the motor axis, the motor shaft passes through the axial hole of each rotor punching, and the outer circumference of the motor shaft includes at least one keyway. Each protrusion is used to embed in a keyway of the motor shaft. Each rotor punching in each first rotor core includes at least one balancing through-hole.

[0049] In the motor rotor provided in the embodiments of the present application, balancing holes are machined into each rotor punching in the first rotor core, arranged axially at both ends of the rotor core. This not only reduces the motor rotor's imbalance but also improves the efficiency of de-weighting during dynamic balancing. Furthermore, only one keyway is required on the motor shaft to transmit torque to the rotor core, reducing the machining accuracy requirements and costs for the motor shaft. This, in turn, reduces the machining costs of the motor rotor.

[0050] An embodiment of the present application further provides a motor, which includes a motor stator and the above-mentioned motor rotor, and the motor rotor is sleeved in the center hole of the motor stator.

[0051] An embodiment of the present application further provides a powertrain, which includes a reducer and a motor as described above, wherein a motor shaft of the motor is drivingly connected to an input shaft of the reducer.

[0052] The embodiment of the present application further provides an electric vehicle. The electric vehicle provided by the embodiment of the present application will be described in detail below with reference to FIG1 .

[0053] Figure 1 is a schematic diagram of the structure of an electric vehicle provided in an embodiment of the present application. As shown in Figure 1, the electric vehicle includes a battery 1, wheels 2, and one or more powertrains 3. The powertrain 3 is used to receive power from the battery 1 and drive the wheels 2, and the powertrain 3 is used to convert electrical energy into mechanical energy. The powertrain 3 includes a motor 30 and a reducer 31. The reducer 31 is in transmission connection with the motor 30. The reducer 31 is used to provide a transmission connection between the motor 30 and the wheels 2.

[0054] The electric vehicles provided in the embodiments of the present application include pure electric vehicles, hybrid electric vehicles, extended-range electric vehicles, plug-in hybrid electric vehicles or new energy vehicles, etc. Among them, pure electric vehicles are also called pure electric vehicle / battery electric vehicle, or simply pure EV / battery EV. Hybrid electric vehicles are also called hybrid electric vehicles, or simply HEV. Extended-range electric vehicles are also called range extended electric vehicles, or simply REEV. Plug-in hybrid electric vehicles are also called plug-in hybrid electric vehicles, or simply PHEV. New energy vehicles are also called new energy vehicles, or simply NEV.

[0055] In some embodiments, the powertrain 3 further includes a controller for controlling the start or stop, forward or reverse rotation, speed increase or decrease, drive torque increase or decrease, braking torque increase or decrease, etc. of the motor 30 .

[0056] The motor 30 includes a motor rotor and a motor stator, and the motor rotor 300 is sleeved in the central hole of the motor stator. The structure of the motor rotor 300 provided in the embodiment of the present application is described in detail below with reference to Figures 2 to 9.

[0057] As shown in Figure 2, the motor rotor 300 includes a motor shaft 310 and a rotor core 320. The outer peripheral surface of the motor shaft 310 includes at least one keyway G. The keyway G is recessed from the outer peripheral surface of the motor shaft 310 toward the interior of the motor shaft 310. The size of the keyway G along the axial direction of the motor is larger than the size of the keyway G along the circumferential direction of the motor. The keyway G includes a notch and a groove bottom arranged oppositely along the radial direction of the motor, and two groove walls arranged oppositely along the circumferential direction of the motor. In some embodiments, in order to easily embed other components such as the protrusion of the rotor punching described below in the keyway G, the size of the two groove walls at one end of the keyway G along the axial direction of the motor is larger than the size of the two groove walls at the other end. In this way, during the assembly process of the other components and the motor shaft 310, one end of the motor shaft 310 can be pushed into the other components along the axial direction of the motor.

[0058] As shown in FIG2 , the motor rotor 300 further includes a rotor core 320. In some embodiments, the rotor core 320 includes at least one first rotor core 3210, with multiple first rotor cores 3210 sequentially arranged along the motor's axial direction. In other embodiments, as shown in FIG2 , the rotor core 3220 includes two first rotor cores 3210 and multiple second rotor cores 3220, with multiple second rotor cores 3220 sequentially arranged between the two first rotor cores 3210 along the motor's axial direction.

[0059] Each rotor lamination in the rotor core 320 includes multiple magnetic steel through-holes N and multiple magnets M. The multiple magnetic steel through-holes N of two adjacent rotor laminations are connected along the axial direction of the motor. Each axially connected magnetic steel through-hole N is used to accommodate a magnet M. Each magnetic steel through-hole N is not connected to the axial hole O of the rotor lamination. Along the circumference of the rotor lamination, multiple magnetic steel through-holes N are distributed around each axial hole O. Along the axial direction of the rotor lamination, each magnetic steel through-hole N penetrates the rotor lamination. The rotor core 320 also includes multiple magnets.

[0060] The multiple magnetic steel through holes N include multiple magnetic steel through hole groups, each group of magnetic steel through holes includes at least one magnetic steel through hole N, the number of the multiple magnetic steel through holes N is a multiple of the number of the multiple magnetic steel through hole groups, and two adjacent groups of magnetic steel through holes along the circumference of the motor are rotationally symmetrical about the center of the shaft hole O.

[0061] The plurality of magnets includes a plurality of magnet groups, each magnet group includes at least one magnet, and the number of the plurality of magnets is a multiple of the number of the plurality of magnet groups. The number of magnets included in each magnet group is equal to the number of magnet through-holes N included in each magnet through-hole group N. In one example, each magnet group includes one magnet M, and each magnet through-hole group includes one magnet through-hole N. In another example, each magnet group includes three magnets, and each magnet through-hole group includes three magnet through-holes, and the three magnet through-holes are arranged in two layers along the radial direction of the rotor punching. One layer of magnet through-holes includes two magnet through-holes arranged in a "V" shape along the circumference of the rotor punching, and another layer of magnet through-holes includes one magnet through-hole, and another layer of magnet through-holes is arranged between one layer of magnet through-holes and the outer peripheral surface of the rotor punching. In another example, as shown in Figures 2, 3, and 5 to 13, each magnetic steel group includes four magnetic steels M1-M4, and each magnetic steel through-hole group includes four magnetic steel through-holes N1-N4. Every two magnetic steel through-holes in the four magnetic steel through-holes form a layer, which are arranged in two layers along the radial direction of the rotor punching, and the two magnetic steel through-holes in each layer are arranged in a "V" shape along the circumference of the punching.

[0062] The projection of each magnetic steel through-hole N along the motor axis along the first direction is smaller than its projection along the second direction. Furthermore, the size of each magnetic steel M along the first direction is smaller than the size of one magnetic steel through-hole N, and the size of each magnetic steel M along the second direction is smaller than the size of one magnetic steel through-hole N. Thus, the multiple magnetic steel through-holes N of two adjacent rotor punchings are connected along the motor axis to form multiple magnetic steel channels, each of which can accommodate one magnetic steel M.

[0063] The first direction, the second direction, and the motor axial direction are perpendicular to each other. The first direction can be understood as the width direction of the magnetic steel through-hole N or the height direction of the magnetic steel N, the second direction can be understood as the length direction of the magnetic steel through-hole N or the width direction of the magnetic steel M, and the motor axial direction can be understood as the length direction of the magnetic steel M. It should be noted that the first direction and the second direction are both relative to the position of a magnetic steel through-hole N. For different magnetic steel through-holes N, the first direction and the second direction may be different.

[0064] Each first rotor core 3210 and each second rotor core 3220 includes a plurality of rotor punchings, which are arranged in sequence along the axial direction of the motor. Each rotor punching includes an axial hole O, which extends through each rotor punching along the axial direction. The inner circumferential surface of the axial hole O of each rotor punching includes at least one protrusion P, which extends from the inner circumference of the axial hole O to the center of the axial hole O. The length of the rotor core 3210 along the axial direction of the motor is less than the length of the keyway G. Along the circumference of the motor, the keyway G and each protrusion form a transition fit or interference fit. Thus, each protrusion P is adapted to fit into a keyway G of the motor shaft 310.

[0065] In some embodiments, the number of protrusions P on each rotor sheet and the number of key slots G on the motor shaft 310 are both one. Thus, along the motor's axial direction, one end of the key slot G on the motor shaft 310 is aligned with the protrusion P on each rotor sheet of the rotor core 320 and pushed into the axial hole O of each rotor sheet of the rotor core 320, completing the assembly of the motor shaft 310 and the rotor core 320.

[0066] As shown in Figures 3 and 4 , after the motor shaft 310 and rotor core 320 are assembled, a gap J1 exists between the bottom of the radial keyway G of the motor and each protrusion P. A gap J2 exists between the connection between each protrusion P of each rotor plate and the inner circumference of the axial hole O of each rotor plate and the outer circumference of the motor shaft 310. Due to the presence of gaps J1 and J2, and the fact that the length of the rotor core 3210 along the motor axis is shorter than the length of the keyway G, the center of gravity of the rotor core 320 deviates from the rotation axis of the motor shaft 310, causing imbalance in the motor rotor.

[0067] Therefore, as shown in Figures 2 and 5 to 13, each rotor punching in each first rotor core 3210 includes at least one balancing through-hole T1, and the balancing through-hole T1 passes through the rotor punching along the axial direction of the rotor punching. The balancing through-hole T1 is used to position the center of gravity of the rotor core 320 on the rotation axis of the motor shaft 310. In this way, not only can the imbalance of the motor rotor be reduced, but the deweighting efficiency of the dynamic balancing of the motor rotor can also be improved. In addition, only one keyway needs to be processed on the motor shaft 310 to transmit torque to the motor rotor core 320, which reduces the processing accuracy requirements and processing costs of the motor shaft 310. In turn, the processing cost of the motor rotor is reduced.

[0068] For example, the balancing through hole T1 of each rotor punching in the first rotor core 3210 can be implemented by way 1 and way 2. It should be noted that way 1 and way 2 can be implemented in combination or separately, and this embodiment of the application does not limit this.

[0069] In method 1, a through hole is added on each rotor punching in the first rotor core 3210 and passes through the rotor punching along the axial direction of the rotor punching as a balancing through hole T1.

[0070] As shown in Figures 5 to 9, balancing holes T1 are provided in the lower half of the rotor laminations, along the direction from the protrusion P toward the center of the rotor laminations. In other words, by removing weight from the side opposite the protrusion P of the first rotor core 3210, such as by adding balancing holes T1 opposite the protrusion P of the first rotor core 3210, the imbalance of the motor rotor 300 is reduced. In this embodiment, as shown in Figures 5 to 9, the angle between the line connecting each balancing hole T1 and the center of each rotor lamination in each first rotor core 3210 and the line connecting each protrusion P and the center of the rotor lamination is approximately θ, with 90°≤θ≤180°.

[0071] In some embodiments, as shown in FIG5 , a rotor punching in a first rotor core 3210 includes a balancing hole T1. The angle between the line connecting the balancing hole T1 and the center of the rotor punching and the line connecting each protrusion P and the center of the rotor punching is approximately 180 degrees.

[0072] Furthermore, in some embodiments, the distance between a trimming through-hole T1 in one rotor punching in one of the first rotor cores 3210 and the center of a rotor punching in the first rotor core 3210 is greater than the distance between a trimming through-hole T1 in another rotor punching and the center of the rotor punching, and the projected area of ​​a trimming through-hole T1 in one rotor punching along the motor axis is smaller than the projected area of ​​a trimming through-hole T1 in another rotor punching. In other words, the greater the distance between the trimming through-hole T1 and the center of the rotor punching, the smaller the projected area of ​​the trimming through-hole T1 along the motor axis.

[0073] In other embodiments, as shown in FIG6 and FIG7 , a rotor punching in a first rotor core 3210 includes a plurality of balancing through holes T1 , and the plurality of balancing through holes T1 are distributed along the circumferential direction and / or along the radial direction of the rotor punching.

[0074] For example, as shown in FIG6 , multiple balancing holes T1 are spaced apart along the circumference of the rotor sheet. The angle between the line connecting one of two adjacent balancing holes T1 and the center of the rotor sheet and the line connecting the other balancing hole T1 and the center of the rotor sheet is approximately less than 180 degrees. By providing multiple balancing holes T1 spaced apart along the circumference of each rotor sheet in the first rotor core 3210, the imbalance of the motor rotor is reduced. This reduces the weight loss and time required to de-weight the motor rotor 300, thereby improving the dynamic balancing efficiency of the motor rotor 300.

[0075] For example, as shown in FIG7 , multiple balancing holes T1 are spaced apart along the radial direction of the rotor sheet. The angle between the line connecting each balancing hole T1 and the center of the rotor sheet and the line connecting each protrusion P and the center of the rotor sheet is approximately 180 degrees. By providing multiple balancing holes T1 spaced apart along the radial direction of each rotor sheet in the first rotor core 3210, the imbalance of the motor rotor 300 is reduced. This reduces the weight loss and time required to de-weight the motor rotor 300, thereby improving the dynamic balancing efficiency of the motor rotor 300.

[0076] In some embodiments, at least two of the plurality of trim holes T1 along the motor axis have at least one different projected area or projected shape. By providing trim holes T1 of different sizes and shapes, the imbalance of the motor rotor 300 is reduced, thereby increasing the flexibility of adjusting the imbalance of the motor rotor 300.

[0077] For example, the projected shape of the trimming through hole T1 along the axial direction of the motor includes, but is not limited to, a circle, a semicircle, a waist, a square, a triangle, a trapezoid, and the like.

[0078] In some embodiments, along the motor's axial direction, the projections of each protrusion P of the two first rotor cores 3210 overlap, and the projection of each balancing through-hole T1 of a rotor punching in one first rotor core 3210 overlaps with the projection of a balancing through-hole T1 of a rotor punching in the other first rotor core 3210. In this way, each rotor punching of the first rotor core 3210 can be produced using only one mold, reducing the production cost of the rotor punchings.

[0079] In some embodiments, a cross-sectional view of one of the two first rotor cores 3210 is shown in FIG8 , and a cross-sectional view of the other first rotor core 3210 is shown in FIG9 . Along the motor's axial direction, the projections of each protrusion P of the two first rotor cores 3210 overlap, while the projections of at least one balancing through-hole T1 of a rotor punching in one first rotor core 3210 do not overlap with the projections of at least one balancing through-hole T1 of a rotor punching in the other first rotor core 3210. This improves the flexibility of adjusting the imbalance of the motor rotor 300.

[0080] In some embodiments, the more balancing through holes T1 are added to each rotor punching in the first rotor core 3210 , the smaller the projected area of ​​the balancing through holes T1 along the axial direction of the motor.

[0081] For example, the area and position of the above-mentioned balancing through hole T1 can be determined by the position of the center of gravity in the established three-dimensional model of the motor rotor.

[0082] Method 2: Use the existing through holes on each rotor punching in the first rotor core 3210 as the balancing through holes T1.

[0083] By modifying the size of the weight-reducing through-holes and / or oil passage through-holes on each rotor punching in the first rotor core 3210 without modifying the size of the magnetic steel through-holes, the imbalance of the motor rotor is reduced while improving the magnetic concentration capacity of the magnetic steel.

[0084] (1) Reusing the oil channel hole as a trim hole

[0085] As shown in Figures 10 to 13, each rotor punching of at least one first rotor core 3210 of the rotor core 320 includes multiple oil passage holes C. The multiple oil passage holes C are distributed circumferentially around an axial hole O. Each oil passage hole C extends axially through the rotor punching. The multiple oil passage holes C in each rotor punching of the first rotor core 3210 are connected axially along the motor to form multiple oil passages, each of which serves as a channel for coolant flow.

[0086] In some embodiments, along the radial direction of the rotor punching, the distance between each oil channel through hole C and the center of the rotor punching is smaller than the distance between each magnetic steel through hole N and the center of the rotor punching.

[0087] In some embodiments, the size of each oil passage through hole C along the circumferential direction of the rotor punching is larger than the radial dimension of each oil passage through hole C. The projected area of ​​each oil passage through hole C is smaller than the projected area of ​​each magnetic steel through hole M.

[0088] Along the motor's axial direction, the projected area of ​​at least one of the multiple oil passage holes C in at least one rotor punching of the first rotor core 3210 is different from that of the other oil passage holes. As shown in Figures 12 and 13, the at least one oil passage hole C is a balancing hole T1. Due to the presence of the at least one oil passage hole C, the multiple oil passage holes C in at least one rotor punching of the first rotor core 3210 are non-rotationally symmetric about the center of the axial hole O. The at least one oil passage hole C can reduce the imbalance of the motor rotor 300. In this way, by modifying the size of the at least one oil passage hole C on each rotor punching in the first rotor core 3210, the imbalance of the motor rotor 300 is reduced, the oil passage hole C of each rotor punching in the first rotor core 3210 is reused, the weight and time required to deweight the motor rotor 300 are reduced, and the dynamic balancing efficiency of the motor rotor 300 is improved.

[0089] In some embodiments, as shown in Figures 10 and 11, the plurality of oil passage holes C include two groups of oil passage holes, each of which is distributed around an axial hole O, and at least one group of oil passage holes includes at least one oil passage hole C. The distance between one group of oil passage holes C1 and the center of the rotor punching is greater than the distance between the other group of oil passage holes C2 and the center of the rotor punching.

[0090] In some embodiments, as shown in FIG10 , at least one oil passage hole C is disposed in the upper half of the rotor punching, along the direction from the protrusion P toward the center of the rotor punching. In other words, by adding weight to the side of the first rotor core 3210 where the protrusion P is located, such as by reducing the area of ​​the oil passage hole C on the side of the first rotor core 3210 where the protrusion P is located, the imbalance of the motor rotor 300 is reduced. In this embodiment, the angle between the line connecting the at least one oil passage hole C and the center of the rotor punching and the line connecting each protrusion P and the center of the rotor punching is approximately less than 90 degrees, and the projected area of ​​at least one oil passage hole C along the axial direction of the rotor punching is smaller than the area of ​​the other oil passage holes C.

[0091] In some embodiments, as shown in FIG11 , at least one oil passage hole C is disposed in the lower half of the rotor punching, along the direction from the protrusion P toward the center of the rotor punching. In other words, by deweighting the side of the first rotor core 3210 opposite the protrusion P, such as by increasing the area of ​​the oil passage hole on the side of the first rotor core 3210 opposite the protrusion P, the imbalance of the motor rotor 300 is reduced. In this embodiment, the angle between the line connecting the at least one oil passage hole C and the center of the rotor punching and the line connecting each protrusion P and the center of the rotor punching is approximately greater than 90 degrees and less than 180 degrees, and the projected area of ​​at least one oil passage hole C along the axial direction of the rotor punching is greater than the area of ​​the other oil passage holes C.

[0092] In some embodiments, as shown in FIG3 , each rotor punching of the at least one second rotor core 3220 also includes the multiple oil passage holes C described above. Along the motor's axial direction, the multiple oil passage holes C of the at least one rotor punching of the second rotor core 3220 are rotationally symmetric about the center of the axial hole O. Furthermore, along the motor's axial direction, the projected area of ​​the multiple oil passage holes C of the at least one rotor punching of the second rotor core 3220 is equal to the projected area of ​​the other oil passage holes C of the at least one rotor punching of the first rotor core 3210. In some embodiments, along the motor's axial direction, the multiple oil passage holes C of each rotor punching of the second rotor core 3220 are connected to the multiple oil passage holes C of each rotor punching of the first rotor core 3210 adjacent to the second rotor core 3220.

[0093] (2) Reusing weight reduction holes as balancing holes

[0094] As shown in Figures 12 and 13, each rotor lamination of at least one first rotor core 3210 of the rotor core 320 includes multiple weight-reducing through-holes W. The weight-reducing through-holes W are used to reduce the mass of the rotor core 320. The multiple weight-reducing through-holes W are distributed circumferentially around an axial hole O. Each weight-reducing through-hole W penetrates the rotor lamination axially. In some embodiments, the radial distance between each weight-reducing through-hole W and the center of the rotor lamination is smaller than the distance between each magnetic through-hole N and the center of the rotor lamination.

[0095] Exemplarily, along the axial direction of the motor, the projection of the weight-reducing through hole W includes but is not limited to a triangle, a trapezoid, and the like.

[0096] Along the axial direction of the motor, the projected area of ​​at least one of the multiple weight-reducing through holes W of at least one rotor punching of the first rotor core 3210 is different from that of the other weight-reducing through holes W. As shown in Figures 12 and 13, at least one weight-reducing through hole W is a balancing through hole T1. Due to the presence of at least one weight-reducing through hole W, the multiple weight-reducing through holes W of at least one rotor punching of the first rotor core 3210 are not rotationally symmetric about the hole center of the axial hole O. In this way, by modifying the size of at least one weight-reducing through hole W on each rotor punching in the first rotor core 3210, the imbalance of the motor rotor 300 is reduced, the weight-reducing through hole W of each rotor punching in the first rotor core 3210 is reused, the weight-reducing through hole W of each rotor punching in the first rotor core 3210 is reduced, the weight-reducing through hole 300 and the time required for de-weighting the motor rotor 300 are reduced, and the dynamic balancing efficiency of the motor rotor 300 is improved.

[0097] In some embodiments, as shown in FIG12 , at least one weight-reducing through-hole W is disposed in the upper half of the rotor sheet, along the direction from the protrusion P toward the center of the rotor sheet. In other words, by adding weight to the side of the first rotor core 3210 where the protrusion P is located, such as by reducing the area of ​​the weight-reducing through-hole on the side of the first rotor core 3210 where the protrusion P is located, the imbalance of the motor rotor 300 is reduced. In this embodiment, the angle between the line connecting the at least one weight-reducing through-hole W and the center of the rotor sheet and the line connecting each protrusion P and the center of the rotor sheet is approximately less than 90 degrees, and the projected area of ​​at least one weight-reducing through-hole W along the axial direction of the rotor sheet is smaller than the area of ​​the other weight-reducing through-holes W.

[0098] In some embodiments, as shown in FIG13 , at least one weight-reducing through-hole W is disposed in the lower half of the rotor punching, along the direction from the protrusion P toward the center of the rotor punching. In other words, by removing weight from the side of the first rotor core 3210 opposite the protrusion P, such as by increasing the area of ​​the weight-reducing through-hole removed from the side of the first rotor core 3210 opposite the protrusion P, the imbalance of the motor rotor 300 is reduced. In this embodiment, the angle between the line connecting the at least one weight-reducing through-hole W and the center of the rotor punching and the line connecting each protrusion P and the center of the rotor punching is approximately greater than 90 degrees and less than 180 degrees, and the projected area of ​​at least one weight-reducing through-hole W along the axial direction of the rotor punching is greater than the area of ​​the other weight-reducing through-holes W.

[0099] In some embodiments, at least one rotor punching of at least one second rotor core 3220 also includes the multiple weight-reducing through-holes W described above. Along the axial direction of the motor, the multiple weight-reducing through-holes W of the at least one rotor punching of the second rotor core 3220 are rotationally symmetric about the center of the axial hole O. Furthermore, along the axial direction of the motor, the projected areas of the multiple weight-reducing through-holes W of the at least one rotor punching of the second rotor core 3220 are equal to the projected areas of the other weight-reducing through-holes W of the at least one rotor punching of the first rotor core 3210.

[0100] It should be noted that, in some embodiments, the oil channel through hole C of each rotor punching of the first rotor core 3210 can also be used to reduce the mass of the rotor core 320, so that each rotor punching of the first rotor core 3210 does not need to be processed with a weight-reducing through hole. In other embodiments, each rotor punching of the first rotor core 3210 includes a weight-reducing through hole W in addition to the oil channel through hole C. Furthermore, in some embodiments, as shown in Figures 12 and 13, along the radial direction of the motor, the distance between each weight-reducing through hole W and the center of the rotor punching is greater than the distance between each oil channel through hole C and the center of the rotor punching. In addition, the scheme of reusing the oil channel through hole and reusing the weight-reducing through hole as the balancing through hole T1 can be implemented separately or in combination, and this application does not limit this.

[0101] For example, the area and position of the above-mentioned balancing through hole T1 can be determined by the position of the center of gravity in the established three-dimensional model of the motor rotor.

[0102] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A motor rotor balanced by rotor punching, characterized in that: The motor rotor comprises: A rotor core, wherein the rotor core comprises two first rotor cores and a plurality of second rotor cores, wherein the plurality of second rotor cores are sequentially arranged between the two first rotor cores along the axial direction of the motor, wherein each of the first rotor cores and each of the second rotor cores comprises a plurality of rotor punchings, each of the rotor punchings comprises an axial hole, and the inner circumferential surface of each of the axial holes comprises at least one protrusion; A motor shaft, the motor shaft passes through the shaft hole of each rotor punching sheet along the motor shaft, the outer peripheral surface of the motor shaft includes at least one keyway, and each of the protrusions is used to be embedded in one of the keyways of the motor shaft; Each of the rotor punchings in each of the first rotor cores includes at least one balancing through hole.

2. The motor rotor according to claim 1, characterized in that: Each of the rotor punchings in one of the first rotor cores comprises a plurality of weight-reducing through holes, and at least one of the balancing through holes is a weight-reducing through hole, wherein: Along the circumference of the rotor punching sheet, the plurality of weight-reducing through holes are distributed around the one shaft hole; Each of the weight-reducing through holes penetrates the rotor punching along the axial direction of the rotor punching, and a projection area of ​​at least one of the plurality of weight-reducing through holes is different from that of the other weight-reducing through holes.

3. The motor rotor according to claim 2, characterized in that: The projected area of ​​the at least one weight-reducing through hole along the axial direction of the rotor punching is smaller than the area of ​​the other weight-reducing through holes, and the angle between the line connecting the at least one weight-reducing through hole and the center of the rotor punching and the line connecting each of the protrusions and the center of the rotor punching is less than 90 degrees; or, The projected area of ​​at least one of the weight-reducing through holes along the axial direction of the rotor punching is larger than the area of ​​the other weight-reducing through holes, and the angle between the line connecting the at least one weight-reducing through hole and the center of the rotor punching and the line connecting each of the protrusions and the center of the rotor punching is larger than 90 degrees and smaller than 180 degrees.

4. The motor rotor according to claim 1, characterized in that: Each of the rotor punchings in one of the first rotor cores comprises a plurality of oil passage holes, and at least one of the balancing holes is an oil passage hole, wherein: Along the circumference of the rotor punching sheet, the plurality of oil channel through holes are distributed around the one shaft hole; Along the axial direction of the rotor punching sheet, each of the oil channel through holes penetrates the rotor punching sheet, the projected area of ​​each of the oil channel through holes is smaller than the projected area of ​​each magnetic steel through hole, and the projected area of ​​at least one of the multiple oil channel through holes is different from that of the other oil channel through holes.

5. The motor rotor according to claim 4, characterized in that: The projected area of ​​the at least one oil passage hole along the axial direction of the rotor punching sheet is smaller than the area of ​​the other oil passage holes, and the angle between the line connecting the at least one oil passage hole and the center of the rotor punching sheet and the line connecting each of the protrusions and the center of the rotor punching sheet is less than 90 degrees; or, The projected area of ​​the at least one oil channel through hole along the axial direction of the rotor punching is larger than the area of ​​the other oil channel through holes, and the angle between the line connecting the at least one oil channel through hole and the center of the rotor punching and the line connecting each of the protrusions and the center of the rotor punching is larger than 90 degrees and smaller than 180 degrees.

6. The motor rotor according to claim 4 or 5, characterized in that: The plurality of oil passage through holes include two groups of oil passage through holes, the two groups of oil passage through holes are respectively distributed around the one shaft hole, at least one group of the oil passage through holes includes the at least one oil passage through hole, wherein: The distance between one group of the two groups of oil passage through holes and the center of the rotor punching sheet is greater than the distance between the other group of the oil passage through holes and the center of the rotor punching sheet.

7. The motor rotor according to claim 2 or 4, characterized in that: Each of the rotor punchings in one of the first rotor cores comprises a plurality of magnetic steel through holes, wherein: Along the axial direction of the rotor punching sheet, each of the magnetic steel through holes penetrates the rotor punching sheet; Along the circumferential direction of the rotor punching sheet, the plurality of magnetic steel through holes are distributed around the one shaft hole; Along the radial direction of the rotor punching sheet, the distance between each weight-reducing through hole or each oil channel through hole and the center of the rotor punching sheet is smaller than the distance between each magnetic steel through hole and the center of the rotor punching sheet.

8. The motor rotor according to claim 1, characterized in that: Along the radial direction of the motor, the angle between the line connecting each balancing through hole of each rotor punching in each first rotor core and the center of the rotor punching and the line connecting each protrusion and the center of the rotor punching is θ, 90°≤θ≤180°.

9. The motor rotor according to claim 8, characterized in that: Each of the rotor punchings in each of the first rotor cores comprises a plurality of the balancing through holes, wherein: Along the circumference of the rotor punching, the multiple balancing through holes are arranged at intervals, and the angle between the line connecting one of the two adjacent balancing through holes and the center of the rotor punching and the line connecting the other balancing through hole and the center of the rotor punching is less than 180 degrees.

10. The motor rotor according to claim 8, characterized in that: The rotor punchings in each of the first rotor cores include a plurality of the balancing through holes, wherein: Along the radial direction of the rotor punching sheet, the plurality of balancing through holes are arranged at intervals, and the angle between the line connecting each of the balancing through holes and the center of the rotor punching sheet and the line connecting each of the protrusions and the center of the rotor punching sheet is equal to 180 degrees.

11. The motor rotor according to claim 9 or 10, characterized in that: At least one of the projected areas or projected shapes of at least two of the plurality of trim through holes along the axial direction of the motor is different.

12. The motor rotor according to claim 1, characterized in that: Along the axial direction of the motor, the projections of each protrusion of the two first rotor cores overlap, and the projections of at least one balancing through hole of the rotor punching in one of the first rotor cores do not overlap with the projections of at least one balancing through hole of the rotor punching in the other first rotor core.

13. The motor rotor according to any one of claims 1 to 5, 8 to 10 and 12, characterized in that: The number of the protrusions on each rotor punching sheet and the number of the keyways on the motor shaft are both one; The length of the keyway along the axial direction of the motor is greater than the length of the rotor core; The notch opening of the keyway and the groove bottom of the keyway are arranged opposite to each other along the radial direction of the motor.

14. A motor, characterized in that: The motor comprises a motor stator and a motor rotor as claimed in any one of claims 1 to 13, wherein the motor rotor is sleeved in a central hole of the motor stator.

15. A powertrain, characterized in that: The power assembly includes a reducer and the motor as claimed in claim 12, wherein a motor shaft of the motor is drivingly connected to an input shaft of the reducer.

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