Patent Description:
A motor is an electromagnetic apparatus that implements electric energy conversion or transfer according to the law of electromagnetic induction, and a main function of the motor is to generate drive torque as a power source of power-consuming devices or various machines. With development of miniaturization of a motor in a powertrain, power density of the motor increases gradually. An excitation motor mainly includes a housing and a front cover plate and a rear cover plate that are located at two ends of the housing. The front cover plate, the rear cover plate, and an inner wall of the housing jointly form a sealed cavity. A stator, a rotor, a rotating shaft, and windings (also referred to as coils) are disposed in the cavity. One end of the rotating shaft extends out of the housing from the front cover plate, the other end of the rotating shaft rotates relative to the rear cover plate, the rotor is sleeved on the rotating shaft, the stator is sleeved on an outer circumference of the rotor, the rotor includes a rotor core and windings disposed around the rotor core, and the stator includes a stator core and coils disposed around the stator core.

A salient-pole motor is used as an example. More windings can be disposed on a rotor of the salient-pole motor, and torque density and power density of the motor can be increased. A pole shoe of a salient-pole rotor fits a wedge accommodated in a slot, to protect the windings and prevent the windings from flying and being damaged under action of centrifugal force when the rotor rotates at a high speed.

As requirements for power density of the motor become higher, requirements for the wedge and the pole shoe become higher. To increase power density of the motor, more windings need to be accommodated. Therefore, effective winding space of the slot needs to be as large as possible, and the wedge and the pole shoe need to be as small as possible. The wedge and the pole shoe need to ensure sufficient strength in a case of a smaller size. Therefore, how to design the rotor becomes an urgent technical problem to be resolved. <CIT> discloses a rotor for a rotating electrical machine that may include a number of pole teeth which carry a field winding, slots formed between the pole teeth, slot wedges provided in the slots, and separators arranged in the slots, the separators extending, starting from the slot wedges, between the windings in a direction toward a slot base. <CIT> discloses a salient pole rotor for a synchronous machine, comprising: - a rotor core with a yoke ring and a plurality of salient poles, each of which has a pole shaft projecting radially from the yoke ring and a pole shoe arranged on the pole shaft, wherein a groove-like pole gap is formed between two adjacent salient poles, - rotor coils for generating an electrically excited magnetic flux, which are wound around the pole shafts and arranged in the pole gaps, and - slot closure elements which are fastened to two adjacent pole shoes in order to close the pole gaps and which are at least partially designed as permanent magnets, wherein the permanent magnets are designed to provide a hybrid excited magnetic flux by superimposing the electrically excited flux by generating a permanently excited magnetic flux and to generate magnetic To reduce stray fluxes during operation of the synchronous machine.

Embodiments of this application provide a rotor, a motor, a powertrain, and a vehicle. The rotor includes wedges and pole shoes. The wedges fit the pole shoes through curved portions. The curved portions can effectively relieve stress concentration of joint portions, increase strength of the wedges and the pole shoes, and effectively increase effective winding space of slots in the rotor. In this way, power density of a motor in which the rotor is used is increased.

According to a first aspect, the invention as defined in claim <NUM> provides a rotor, including: a rotor core, a plurality of slots, and a rotating shaft. Each slot includes one wedge, and rotor windings are wound in each slot. The rotor core is sleeved on the rotating shaft, and the plurality of slots are disposed at intervals along a circumferential direction of the rotor core. The rotor core includes a rotor core body and a plurality of pole shoes, and the plurality of pole shoes are disposed at intervals along a circumferential direction of the rotor core body. The pole shoe includes a pole shoe body and two symmetrical hook-shaped pole shoe end portions. The hook-shaped pole shoe end portion becomes thinner along a circumferential direction relative to the pole shoe body and includes at least one first curved portion. The wedge includes a wedge body and two symmetrical first wedge portions, each first wedge portion includes at least one second curved portion, and each first wedge portion fits one hook-shaped pole shoe end portion of one of the pole shoes.

To implement fitting between the first wedge portion and the first curved portion, the at least one second curved portion included in the first wedge portion needs to be in pairs with the at least one first curved portion of the hook-shaped pole shoe end portion.

It should be noted that a "curved portion" in this embodiment of this application may be alternatively replaced with a circular arc, a curve, a curved surface, a circular arc surface, an arc surface, or an arc. For example, a convex curved portion may also be referred to as a convex circular arc, a convex curved surface, a convex arc surface, or a convex arc; and a concave curved portion may also be referred to as a concave circular arc, a concave curved surface, a concave arc surface, or a concave arc. This is not limited herein.

In the invention, the wedges fit the pole shoes through curved portions. The curved portions can effectively relieve stress concentration of joint portions, increase strength of the wedges and the pole shoes, and effectively increase effective winding space of the slots in the rotor. In this way, strength of the wedges and the pole shoes is increased, a maximum speed of the motor can also be increased, and power density of the motor is increased.

With reference to the first aspect, in some implementations, the first curved portion includes a first concave curved portion and/or a first convex curved portion; and the first wedge portion includes a second convex curved portion and/or a second concave curved portion. The first concave curved portion of the first curved portion fits the second convex curved portion of the first wedge portion, and/or the first convex curved portion of the first curved portion fits the second concave curved portion of the first wedge portion.

Optionally, the first curved portion may include one or more first concave curved portions, one or more first convex curved portions, and/or one or more line segments. The first wedge portion may include one or more second concave curved portions, one or more second convex curved portions, and/or one or more line segments. The first wedge portion separately fits first curved portions in hook-shaped pole shoe end portions of two adjacent pole shoes.

The first wedge portion fits the first curved portions through a plurality of curved portions, to further relieve stress concentration of the joint portions, increase strength of the wedges and the pole shoes, and effectively increase the effective winding space of the slots wound in the rotor. In this way, strength of the wedges and the pole shoes is increased, a maximum speed of the motor can also be increased, and power density of the motor is increased.

According to the invention, the pole shoe further includes a second pole shoe portion, and the second pole shoe portion is connected to the first curved portion. The second pole shoe portion is in an eccentric circular arc shape, and a center position of the eccentric circular arc shape does not coincide with an axis center of the rotating shaft; or the second pole shoe portion is in an arc shape of an air gap secant function.

Optionally, one or more concave curved portions, one or more convex curved portions, and/or one or more line segments may be further included between the second pole shoe portion and the first curved portion. The second pole shoe portion is connected to the first curved portion through the foregoing structure.

The foregoing pole shoe structure is used, so that torque fluctuation of the motor in which the pole shoe is used can be effectively reduced, and performance of noise, vibration, and harshness (NVH) of the motor can be improved.

With reference to the first aspect, in some implementations, an air gap length of the second pole shoe portion satisfies δ(θ) = δ<NUM> · secθ, where δ(θ) represents the air gap length of the second pole shoe portion, δ<NUM> represents an air gap length at a position of a symmetry line of a pole arc curve in the pole shoe, and θ represents a circumferential angle between a radial line on which the second pole shoe portion is located and the symmetry line of the pole shoe. There is an air gap between an outer circumferential surface of the rotor core and an inner cavity wall of a stator. The pole arc curve encloses a main area in which the pole shoe faces an air gap.

According to the invention, the pole shoe further includes a third pole shoe portion, and the third pole shoe portion includes one or more third concave curved portions. The third pole shoe portion is tangent to the first curved portion, the third pole shoe portion is tangent to the second pole shoe portion, and the third pole shoe portion is used to extend a circumferential length of the pole shoe. In this way, the pole shoe can accommodate more rotor windings, and torque density and power density of the motor in which the rotor is used are increased.

Optionally, the third pole shoe portion may further include one or more line segments and one or more third concave curved portions.

With reference to the first aspect, in some implementations, the wedge body is used to isolate rotor windings on two sides, so that the wedge performs an insulation function. The wedge may be made of an insulation material.

With reference to the first aspect, in some implementations, the wedge further includes a second wedge portion, the second wedge portion is formed between the two first wedge portions, and the second wedge portion includes at least one concave curved portion. Two sides of the second wedge portion each are connected to one pair of first wedge portions. The second wedge portion is in an arc surface shape, so that stress concentration in an area of an arc surface can be relieved, and strength of the wedge can be increased.

With reference to the first aspect, in some implementations, the wedge further includes one or more pairs of third wedge portions; each pair of third wedge portions are symmetrically located on two sides of the wedge body; each pair of third wedge portions are symmetrical along a symmetry axis of the wedge; and the third wedge portion includes one or more circular arc curved portions and/or one or more line segments. The circular arc curved portion may be a convex curved portion, or may be a concave curved portion, or may be a combination of a convex curved portion and a concave curved portion. This is not limited herein. Bonding strength between the wedge and potting compound is increased through the third wedge portion, and stability of the rotor is improved.

With reference to the first aspect, in some implementations, when the wedge includes the plurality of pairs of third wedge portions, the plurality of pairs of third wedge portions are different in size and/or shape. In this way, strength of the wedge is increased, and stability of the rotor is further improved.

With reference to the first aspect, in some implementations, the wedge further includes a fourth wedge portion, and a radial bottom of the wedge body includes the fourth wedge portion. The rotor core further includes a first rotor core portion. The first rotor core portion radially faces toward the slot. A plurality of first rotor core portions are disposed at intervals along a circumferential direction of the rotor core body. The fourth wedge portion fits the first rotor core portion, to implement connection between the wedge and the rotor core. In this way, strength of a joint portion between the wedge and the rotor core is increased, and stability of the rotor is further improved.

With reference to the first aspect, in some implementations, the slot is filled with the potting compound. The potting compound is bonded to the wedge, the potting compound is bonded to the pole shoe, and the potting compound is bonded to the rotor windings. The wedges, the pole shoes, the rotor windings, and the rotor core inside the rotor are solidified as a whole by using the potting compound. In this way, strength of the rotor is increased, and stability of the rotor is improved.

According to a second aspect, an embodiment of this application provides a motor, including a stator and the rotor according to any one of the implementations of the first aspect. The stator is sleeved on an outer circumference of a rotor core of the rotor, and stator windings are disposed on the stator. Wedges fit pole shoes through curved portions. The curved portions can effectively relieve stress concentration of joint portions, increase strength of the wedges and the pole shoes, and effectively increase effective winding space of slots in the rotor. In this way, strength of the wedges and the pole shoes is increased, a maximum speed of the motor can also be increased, and power density of the motor is increased. The motor is an excitation motor.

According to a third aspect, an embodiment of this application provides a powertrain, including the motor according to any one of the foregoing implementations of the first aspect. The motor ensures that the powertrain keeps high efficiency in various running statuses.

With reference to the third aspect, in some implementations, the powertrain further includes a controller and a reducer. The controller is connected to the motor, the reducer is connected to the motor, the controller is configured to control working of the motor, and the reducer is configured to control a rotation speed of the motor.

According to a fourth aspect, an embodiment of this application provides a vehicle. The vehicle includes a vehicle frame and the motor according to any one of the foregoing implementations of the first aspect, and the motor is mounted on the vehicle frame. The motor enables that the vehicle keeps high efficiency in various running statuses, so that an endurance mileage of the vehicle can be effectively increased, and comprehensive running efficiency of the vehicle can be increased.

The following describes embodiments of this application with reference to accompanying drawings. A person of ordinary skill in the art may learn that, with technology development and emergence of a new scenario, the technical solutions provided in embodiments of this application are also applicable to a similar technical problem.

In the specification, claims, and accompanying drawings of this application, the terms "first", "second", and the like are intended to distinguish between similar objects but do not necessarily indicate a specific order or sequence. It should be understood that the terms used in such a way are interchangeable in proper circumstances. This is merely a discrimination manner that is used when objects having a same attribute are described in embodiments of this application. In addition, the terms "include", "having" and any other variants mean to cover the non-exclusive inclusion, so that a process, method, system, product, or device that includes a series of units is not necessarily limited to those units, but may include other units not expressly listed or inherent to such a process, method, product, or device.

In embodiments of this application, "connection" is a physical connection, or a connection that can be made, or fitting, or contacting, or embedding, or clamping, or inosculating, or the like. The "connection" may alternatively be a location relationship between parts in a physical whole. This is not limited herein.

Electric excitation synchronous motors can be classified into a salient-pole motor and a hidden-pole motor, and an electric excitation synchronous motor used in a new energy vehicle usually uses a salient-pole rotor structure. A salient-pole rotor can accommodate more rotor windings, to increase torque density and power density of the motor. A pole shoe of the salient-pole rotor fits a wedge accommodated in a slot, to protect the windings and prevent the windings from flying and being damaged under action of centrifugal force when the rotor rotates at a high speed.

As requirements for power density of the motor become higher, requirements for the wedge and the pole shoe become higher. To increase power density of the motor, more windings need to be accommodated. Therefore, effective winding space of the slot needs to be as large as possible, and the wedge and the pole shoe need to be as small as possible. The wedge and the pole shoe need to ensure sufficient strength in a case of a smaller size. Therefore, how to design the rotor becomes an urgent technical problem to be resolved.

To resolve the foregoing technical problem, an embodiment of this application provides a rotor. A motor in which the rotor is used may be used in an electric vehicle ( EV), a pure electric vehicle (PEV), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV), a new energy vehicle, battery management, a motor driver, a power converter, or the like.

In this embodiment of this application, an example in which a motor is used in an electric vehicle is used for description. <FIG> is a schematic diagram of a structure of the electric vehicle. The electric vehicle <NUM> may include a vehicle frame <NUM> and a powertrain. The powertrain is mounted on the vehicle frame <NUM>. The vehicle frame <NUM> is used as a structural framework of the electric vehicle, and is configured to support, fasten, and connect various systems, and bear a load inside a vehicle system and a load from an external environment.

The powertrain is a system that includes a series of components and is configured to produce power and transmit the power to a road surface. Refer to <FIG>. The powertrain may include controllers <NUM> and motors <NUM>. The controller <NUM> is electrically connected to the motor <NUM> and is configured to control working of the motor <NUM>. The powertrain may further include reducers <NUM>. The reducer <NUM> is configured to be mechanically connected to the motor <NUM>, and is configured to reduce a rotation speed of the motor <NUM> and increase output torque of the motor <NUM>, to adjust a speed of the vehicle.

The electric vehicle <NUM> further includes wheels <NUM> disposed on the vehicle frame <NUM>. A rotating shaft of the powertrain is connected to the wheels <NUM> through transmission components. In this way, the rotating shaft of the powertrain outputs power, and the transmission components transmit the power to the wheels <NUM>, so that the wheels <NUM> rotate. In this embodiment of this application, the powertrain may include one, two, or more motors <NUM>. When there is one motor, the motor is connected to two front wheels or two rear wheels through transmission components. When there are two motors, one of the motors is connected to the two front wheels through transmission components, and the other motor is connected to the two rear wheels through other transmission components.

It should be noted that the electric vehicle <NUM> is merely used as an example for description, and the electric vehicle <NUM> may further include another component. This is not limited herein.

Further, <FIG> is a schematic diagram of a structure of a motor according to an embodiment of this application. A motor <NUM> includes a stator <NUM> and a rotor <NUM>. <FIG> is a schematic diagram of a structure of a rotor according to an embodiment of this application. The rotor <NUM> includes pole shoes <NUM>, wedges <NUM>, a rotor core <NUM>, rotor windings <NUM>, and a rotating shaft <NUM>. As shown in <FIG>, the rotor core <NUM> and the rotating shaft <NUM> each may be cylindrical, and have an axial direction and a circumferential surface. The rotor core <NUM> has an axial hole extending along the axial direction, and the rotor core <NUM> is sleeved on the rotating shaft <NUM> through the axial hole and is fastened to the rotating shaft <NUM>, so that the rotating shaft <NUM> rotates with the rotor core <NUM>.

The stator <NUM> may have a cylindrical inner cavity. The stator <NUM> is sleeved on an outer circumference of the rotor core <NUM>, and the rotor core <NUM> is located in the inner cavity of the stator <NUM>. The stator <NUM> includes a stator core and stator windings disposed around the stator core. An air gap is between an outer circumferential surface of the rotor core <NUM> and an inner cavity wall of the stator <NUM>. The rotating shaft <NUM> penetrates out of the inner cavity of the stator <NUM>, so that the rotating shaft <NUM> is connected to the reducer <NUM> to output torque.

The following describes in detail the rotor <NUM> provided in this embodiment of this application. Refer to <FIG>. The rotor <NUM> includes the rotor core <NUM>, a plurality of wedges <NUM>, a plurality of pole shoes <NUM>, a plurality of rotor windings <NUM>, and the rotating shaft <NUM>. The rotor core <NUM> is sleeved on the rotating shaft <NUM>. The rotor windings <NUM> are wound in each slot, and a plurality of slots are disposed at intervals along a circumferential direction of the rotor core <NUM>. The rotor windings <NUM> are wound in the slots of the rotor core <NUM>, and the plurality of rotor windings <NUM> are disposed at intervals along the circumferential direction of the rotor core <NUM>. The rotor core <NUM> includes a rotor core body and the plurality of pole shoes <NUM>, and the plurality of pole shoes <NUM> are disposed at intervals along a circumferential direction of the rotor core body. The wedge <NUM> is disposed in a slot opening that is in the slot and that is away from the rotating shaft <NUM>. The plurality of wedges <NUM> are disposed at intervals along the circumferential direction of the rotor core body.

Further, the wedge <NUM> is of a closed solid structure. The wedge <NUM> may be made of an insulation material, for example, a polymer.

Further, the pole shoe <NUM> may be made of a magnetic conductive material such as a silicon steel sheet.

<FIG> is a schematic diagram of a structure of a pole shoe according to an embodiment of this application. A pole shoe <NUM> includes two symmetrical hook-shaped pole shoe end portions <NUM> and a pole shoe body <NUM>. The two hook-shaped pole shoe end portions <NUM> are axisymmetrically disposed along the pole shoe body. The hook-shaped pole shoe end portion <NUM> becomes thinner along a circumferential direction relative to the pole shoe body and includes at least one first curved portion <NUM>. An area, facing an air gap, between the two hook-shaped pole shoe end portions <NUM> is referred to as a second pole shoe portion <NUM>.

Optionally, one or more concave curved portions, and/or one or more convex curved portions, and/or one or more line segments may be further included between the second pole shoe portion <NUM> and the first curved portion <NUM>. The second pole shoe portion <NUM> is connected to the first curved portion <NUM> through the foregoing structure.

As shown in <FIG> and <FIG>, the hook-shaped pole shoe end portion <NUM> includes the first curved portion <NUM>. The first curved portion <NUM> includes one or more first concave curved portions <NUM>, and/or one or more first convex curved portions <NUM>, and/or one or more line segments.

<FIG> is a schematic diagram of a structure of a wedge according to an embodiment of this application. A first wedge portion <NUM> fits first curved portions <NUM> in hook-shaped pole shoe end portions <NUM> of two adjacent pole shoes <NUM>.

To implement fitting between the first wedge portion <NUM> and the first curved portion <NUM>, at least one second convex curved portion <NUM> and/or at least one second concave curved portion <NUM> that are/is included in the first wedge portion <NUM> needs to be in pairs with at least one first convex curved portion <NUM> and/or at least one first concave curved portion <NUM> that are/is included in the first curved portion <NUM>.

For example, "being in pairs" may be understood as "corresponding to". If the first wedge portion <NUM> includes one second convex curved portion <NUM>, the first curved portion <NUM> includes one first concave curved portion <NUM>, the second convex curved portion <NUM> of the first wedge portion <NUM> and the first concave curved portion <NUM> of the first curved portion <NUM> are in a pair, and the second convex curved portion <NUM> of the first wedge portion <NUM> fits the first concave curved portion <NUM> of the first curved portion <NUM>.

If the first wedge portion <NUM> includes one second concave curved portion <NUM>, the first curved portion <NUM> includes one first convex curved portion <NUM>, the second concave curved portion <NUM> of the first wedge portion <NUM> and the first convex curved portion <NUM> of the first curved portion <NUM> are in a pair, and the second concave curved portion <NUM> of the first wedge portion <NUM> fits the first convex curved portion <NUM> of the first curved portion <NUM>.

It should be noted that a "curved portion" in this embodiment of this application may be alternatively replaced with a circular arc, a curve, a curved surface, a circular arc surface, an arc surface, or an arc. For example, a convex curved portion may also be referred to as a convex circular arc, a convex curved surface, or a convex arc surface. This is not limited herein.

One wedge <NUM> includes one pair of first wedge portions <NUM>. The pair of wedge portions <NUM> are located on two sides of a wedge body <NUM> and are symmetrical along a symmetry axis of the wedge <NUM>. An area, facing an air gap, between the pair of first wedge portions <NUM> is referred to as a second wedge portion <NUM>.

<FIG> is a schematic diagram of a partial structure of a rotor according to an embodiment of this application. A wedge <NUM> is connected to two adjacent pole shoes <NUM>. The wedge <NUM> includes first wedge portions <NUM>, and the first wedge portion <NUM> includes at least one curved portion. The first wedge portion <NUM> may include one or more second concave curved portions <NUM>, and/or one or more second convex curved portions <NUM>, and/or one or more line segments.

Optionally, the wedge <NUM> may further include a fourth wedge portion <NUM>, and a radial bottom of the wedge body <NUM> includes the fourth wedge portion <NUM>. The rotor core <NUM> further includes a first rotor core portion <NUM>. The first rotor core portion <NUM> radially faces toward the slot. A plurality of first rotor core portions <NUM> are disposed at intervals along the circumferential direction of the rotor core body. The fourth wedge portion <NUM> fits the first rotor core portion <NUM>, to implement connection between the wedge <NUM> and the rotor core <NUM>. The fourth wedge portion <NUM> includes one or more curved portions and/or one or more line segments. The first rotor core portion <NUM> includes one or more curved portions and/or one or more line segments. The foregoing structures are used, to improve stability of the wedge <NUM> in the slot. In addition, it is ensured that a length of the wedge body <NUM> is long enough, so that the wedge <NUM> is enough to fully isolate two rotor windings <NUM> in the slot, and an insulation function is implemented.

For example, in addition to a V-shaped structure shown in <FIG>, the fourth wedge portion <NUM> may be of another structure, for example, a W-shaped structure or a U-shaped structure. This is not limited herein.

Optionally, the slot is filled with potting compound <NUM>. The potting compound <NUM> is bonded to the wedge <NUM>. The potting compound <NUM> is bonded to the pole shoe <NUM>. The potting compound <NUM> is bonded to the rotor windings <NUM>. The pole shoe <NUM>, the wedge <NUM>, and the rotor windings <NUM> are solidified as a whole by using the potting compound, and strength of the components in the slot is increased.

In this embodiment of this application, the wedges fit the pole shoes through the curved portions. The curved portions can effectively relieve stress concentration of joint portions, increase strength of the wedges and the pole shoes, and effectively increase effective winding space of the slots in the rotor. In this way, strength of the wedges and the pole shoes is increased, a maximum speed of the motor can also be increased, and power density of the motor is increased.

Next, the pole shoe <NUM> and the wedge <NUM> in the rotor <NUM> are separately described in detail.

First, the pole shoe <NUM> is described. <FIG> is a schematic diagram of a structure of a pole shoe according to an embodiment of this application. The pole shoe <NUM> includes the first curved portion <NUM>, a second pole shoe portion <NUM>, and a third pole shoe portion <NUM>. The third pole shoe portion <NUM> included in the hook-shaped pole shoe end portion <NUM> includes one or more third concave curved portions and optionally one or more line segments. The third pole shoe portion <NUM> is tangent to the first curved portion <NUM>. The third pole shoe portion <NUM> is tangent to the second pole shoe portion <NUM>. The third pole shoe portion <NUM> is used to extend a circumferential length of the pole shoe. In this way, the pole shoe can accommodate more rotor windings <NUM>, and torque density and power density of the motor in which the rotor <NUM> is used are increased. As shown in <FIG>, the third pole shoe portion <NUM> includes one third concave curved portion.

For the hook-shaped pole shoe end portion <NUM>, there may be a plurality of implementation solutions. The following provides examples for description with reference to the accompanying drawings.

In a possible implementation solution, refer to <FIG> is a schematic diagram of a structure of a hook-shaped pole shoe end portion according to an embodiment of this application. The hook-shaped pole shoe end portion <NUM> includes the first concave curved portion <NUM>, a smooth transition arc 1b, a convex curved portion 1c, and a concave curved portion 1d. The first concave curved portion <NUM> fits the first wedge portion <NUM>, and the concave curved portion 1d is used to extend the circumferential length of the pole shoe <NUM>. The first curved portion <NUM> includes the first concave curved portion <NUM>. The third pole shoe portion <NUM> includes the concave curved portion 1d.

Portions between the first concave curved portion <NUM> and the concave curved portion 1d include the smooth transition arc 1b and the convex curved portion 1c. Structures of the smooth transition arc 1b and the convex curved portion 1c can reduce thickness of the pole shoe <NUM>, reduce magnetic leakage, and weaken adverse impact caused by circumferential extension of the pole shoe <NUM>.

In another possible implementation solution, refer to <FIG> is a schematic diagram of another structure of a hook-shaped pole shoe end portion according to an embodiment of this application. The hook-shaped pole shoe end portion <NUM> includes the first convex curved portion <NUM>, the first concave curved portion <NUM>, a smooth transition arc 2c, a line segment 2d, a smooth transition arc 2e, a line segment 2f, a smooth transition arc <NUM>, a line segment <NUM>, and a concave curved portion 2i. The first convex curved portion <NUM> and the first concave curved portion <NUM> fit the first wedge portion <NUM>. In this case, the first wedge portion <NUM> includes the second concave curved portion <NUM> that is in pairs with (or that corresponds to) the first convex curved portion <NUM>, and the second convex curved portion <NUM> that is in pairs with (or that corresponds to) the first concave curved portion <NUM>. The first curved portion <NUM> includes the first concave curved portion <NUM> and the first convex curved portion <NUM>. The third pole shoe portion <NUM> includes the concave curved portion 2i and the line segment <NUM>. The line segment <NUM> and the concave curved portion 2i are used to extend the circumferential length of the pole shoe <NUM>.

Portions between the first concave curved portion <NUM> and the line segment <NUM> include the smooth transition arc 2c, the line segment 2d, the smooth transition arc 2e, the line segment 2f, and the smooth transition arc <NUM>. Structures of the smooth transition arc 2c, the line segment 2d, the smooth transition arc 2e, the line segment 2f, and the smooth transition arc <NUM> can reduce thickness of the pole shoe <NUM>, reduce magnetic leakage, and weaken adverse impact caused by circumferential extension of the pole shoe <NUM>.

In another possible implementation solution, the first curved portion <NUM> of the hook-shaped pole shoe end portion <NUM> includes the first convex curved portion <NUM>. In this case, the first wedge portion <NUM> includes the second concave curved portion <NUM> that is in pairs with (or corresponds to) the first convex curved portion <NUM>.

It should be noted that the foregoing smooth transition arcs may include one or more arcs (or arc surfaces), or may include a combination of one or more arcs (arc surfaces) and line segments. This is not limited herein.

For the second pole shoe portion <NUM>, there are also a plurality of possible implementations. The following describes the plurality of possible implementations with reference to the accompanying drawings. <FIG> is a schematic diagram of still another structure of a pole shoe according to an embodiment of this application. The second pole shoe portion <NUM> is in an eccentric circular arc shape, and a center position of the eccentric circular arc shape does not coincide with an axis center of the rotating shaft.

In another possible implementation, the second pole shoe portion is in an arc shape of an air gap secant function. Specifically, <FIG> is a schematic diagram of yet another structure of a pole shoe according to an embodiment of this application. An air gap length of the second pole shoe portion <NUM> satisfies: δ(θ) = δ<NUM> · secθ, where δ(θ) represents the air gap length of the second pole shoe portion <NUM>, δ<NUM> represents an air gap length at a position of a symmetry line of a pole arc curve in the pole shoe <NUM>, and θ represents a circumferential angle between a radial line on which the second pole shoe portion <NUM> is located and the symmetry line of the pole shoe <NUM>. The air gap length is a length of a gap between the stator <NUM> and the rotor <NUM> in the motor. The pole arc curve encloses a main area in which the pole shoe <NUM> faces the air gap.

Next, the wedge <NUM> is described. There are also a plurality of implementation solutions for the wedge <NUM>, for example, the structure shown in <FIG>, or a variation of the structure shown in <FIG>. For ease of understanding, refer to <FIG> is a schematic diagram of another structure of a wedge according to an embodiment of this application. The wedge <NUM> includes the first wedge portions <NUM>, the second wedge portion <NUM>, the fourth wedge portion <NUM>, and the wedge body <NUM>.

One wedge <NUM> includes one pair of first wedge portions <NUM>. The pair of wedge portions <NUM> are located on the two sides of the wedge body <NUM> and are symmetrical along the symmetry axis of the wedge <NUM>. The area, facing the air gap, between the pair of first wedge portions <NUM> is referred to as the second wedge portion <NUM>. <FIG> is used as an example. The first wedge portion <NUM> includes one second convex curved portion <NUM>.

It may be understood that the first wedge portion <NUM> may further have another structure, to fit the first curved portion <NUM>. For ease of understanding, refer to <FIG> is a schematic diagram of a structure of a first wedge portion according to an embodiment of this application. The first wedge portion <NUM> includes one second convex curved portion <NUM> and one second concave curved portion <NUM>, and the first wedge portion <NUM> fits the first curved portion <NUM> through the second convex curved portion <NUM> and the second concave curved portion <NUM>. Specifically, <FIG> is a schematic diagram of fitting between the wedge <NUM> and the pole shoe <NUM>. Refer to <FIG> is a schematic diagram of another partial structure of a rotor according to an embodiment of this application. Stability of the wedge <NUM> and the pole shoe <NUM> is improved through the plurality of curved portions.

The wedge further includes the second wedge portion <NUM>, the second wedge portion <NUM> includes at least one concave curved portion, and two sides of the second wedge portion <NUM> are connected to one pair of first wedge portions <NUM>. The second wedge portion <NUM> is in an arc surface shape, so that stress concentration in an area of an arc surface can be relieved, and strength of the wedge <NUM> can be increased.

Optionally, the second wedge portion <NUM> may further include one or more line segments. Alternatively, the second wedge portion <NUM> may further include one or more convex curved portions, and/or one or more concave curved portions, and/or one or more line segments. For example, the second wedge portion <NUM> includes one concave curved portion and two line segments tangent to the concave curved portion, and the concave curved portion is connected to the first wedge portions <NUM> through the two line segments on the two sides.

Optionally, the wedge <NUM> may further include one or more pairs of third wedge portions <NUM>. The wedge <NUM> shown in <FIG> includes one pair of third wedge portions <NUM>. The wedge <NUM> shown in <FIG> does not include the third wedge portion <NUM>. Each pair of third wedge portions <NUM> are located on the two sides of the wedge body <NUM>, and are symmetrical along the symmetry axis of the wedge <NUM>. The third wedge portion <NUM> includes one or more circular arc curved portions and/or one or more line segments. The circular arc curved portion may be a convex curved portion, or may be a concave curved portion, or may be a combination of a convex curved portion and a concave curved portion. This is not limited herein.

For example, the wedge <NUM> includes the plurality of pairs of third wedge portions <NUM>. Refer to <FIG> is a schematic diagram of a structure of a third wedge portion according to an embodiment of this application. The wedge <NUM> includes two pairs of third wedge portions <NUM>.

Optionally, the pairs of third wedge portions <NUM> are different in size and/or shape. For example, concave curved portions (or grooves) of one pair of third wedge portions are wide and shallow, and concave curved portions (or grooves) of the other pair of third wedge portions are narrow and deep. For another example, concave curved portions (or grooves) of one pair of third wedge portions are wide and deep, and concave curved portions (or grooves) of the other pair of third wedge portions are shallow and narrow. This is not limited herein.

Optionally, when the wedge <NUM> includes the plurality of pairs of third wedge portions <NUM>, the plurality of third wedge portions <NUM> may be the same in size, and/or the plurality of third wedge portions <NUM> may be the same in shape.

Bonding strength between the wedge and the potting compound is increased through the third wedge portion, and stability of the rotor is improved.

For descriptions of a direction or a position, refer to "a radial direction", "an axial direction", and "a circular direction". In the meaning of this application, a rotation axis of the rotor <NUM> is used.

It should be understood that "one embodiment" or "an embodiment" mentioned in the entire specification means that particular features, structures, or characteristics related to embodiments are included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not refer to a same embodiment. In addition, these particular features, structures, or characteristics may be combined in one or more embodiments in any appropriate manner. The execution sequences of the processes should be determined according to functions and internal logic of the processes, and should not be construed as any limitation on the implementation processes of embodiments of this application.

In addition, the term "system" in this specification may be used interchangeably in this specification. The term "and/or" in this specification describes only an association relationship for describing associated objects and represents that three relationships may exist.

Claim 1:
A rotor (<NUM>), comprising:
a rotor core (<NUM>), a plurality of slots, and a rotating shaft (<NUM>), wherein each slot comprises one wedge (<NUM>), and rotor windings (<NUM>) are wound in each slot;
the rotor core (<NUM>) is sleeved on the rotating shaft (<NUM>), and the plurality of slots are disposed at intervals along a circumferential direction of the rotor core (<NUM>);
the rotor core (<NUM>) comprises a rotor core body and a plurality of pole shoes (<NUM>), and the plurality of pole shoes (<NUM>) are disposed at intervals along a circumferential direction of the rotor core body;
the pole shoe (<NUM>) comprises a pole shoe body (<NUM>) and two symmetrical hook-shaped pole shoe end portions (<NUM>), wherein each hook-shaped pole shoe end portion (<NUM>) becomes thinner along a circumferential direction relative to the pole shoe body (<NUM>) and comprises at least one first curved portion (<NUM>); and
the wedge (<NUM>) comprises a wedge body (<NUM>) and two symmetrical first wedge portions (<NUM>), each first wedge portion (<NUM>) comprises at least one second curved portion, and each first wedge portion (<NUM>) fits one first curved portion (<NUM>) of a hook-shaped pole shoe end portion (<NUM>) of one of the pole shoes (<NUM>), characterised in that
the pole shoe (<NUM>) further comprises a second pole shoe portion (<NUM>), and the second pole shoe portion (<NUM>) is connected to the first curved portions (<NUM>); and
the second pole shoe portion (<NUM>) is in an eccentric circular arc shape, and a center position of the eccentric circular arc shape does not coincide with an axis center of the rotating shaft (<NUM>); or
the second pole shoe portion (<NUM>) is in an arc shape of an air gap secant function: and
wherein the pole shoe (<NUM>) further comprises third pole shoe portions (<NUM>), and each third pole shoe portion (<NUM>) comprises one or more third concave curved portions;
each third pole shoe portion (<NUM>) is tangent to a first curved portion (<NUM>);
each third pole shoe portion (<NUM>) is tangent to a second pole shoe portion (<NUM>); and
each third pole shoe portion (<NUM>) is used to extend a circumferential length of the pole shoe (<NUM>).