Highly integrated motor

Abstract

A highly integrated motor comprises: a housing having a mounting cavity; the stator assembly is mounted in the mounting cavity; the motor comprises a stator and a rotor assembly coaxially installed in the stator, the rotor assembly comprises a rotor support and a rotor core, the rotor support comprises an installation sleeve and a connecting piece, the rotor core is fixedly arranged on the outer wall of the installation sleeve, the connecting piece is arranged in the installation sleeve and close to the axial side of the installation sleeve, and the connecting piece is arranged in the installation sleeve and close to the axial side of the installation sleeve. The connecting piece is connected with an engine crankshaft; the end face of the end, away from the connecting piece, of the shell is concaved inwards to form an inwards-concaved part extending into the mounting sleeve, and a containing space used for mounting an electric controller is formed in the inwards-concaved part. The motor is high in integration level, and electric control can be partially or completely integrated into the rotor assembly of the motor.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electric machines, and particularly relates to a highly integrated electric machine. BACKGROUND

[0002] In the field of new energy vehicles and industrial drives, electric machines as core power components are rapidly developing towards high voltage, high speed and high integration. The compactness of the electric machine structure plays a crucial role in adapting to different vehicle platforms, shortening the production process and reducing manufacturing costs.

[0003] Traditional electric machine structures, especially those used in hybrid or specific drives, usually adopt a fixed layout pattern. For example, a typical existing electric machine structure includes a housing, a stator assembly, a rotor assembly, and necessary bearings and position detection components (such as an eddy current sensor target wheel or a resolver rotor). The rotor assembly is usually indirectly or directly connected to the engine crankshaft through a rotor shaft (or rotor support). In order to maintain the rotation stability and positioning accuracy of the rotor, a bearing is usually provided at the end of the rotor away from its output end, which is supported by a bearing steel sleeve fixed on the housing. At the same time, the sensor (such as the target wheel of the eddy current sensor or the rotor of the resolver) for detecting the position of the rotor (i.e. the relative angle between the stator and the rotor) is usually installed outside this bearing. The electronic control unit (ECU) is usually arranged independently outside the electric machine or mounted on the outer end face of the electric machine housing.

[0004] The above-mentioned traditional structure has obvious technical defects: first, in order to accommodate the electric machine bearing and its supporting steel sleeve, as well as the installation space of the position sensor, the electric machine must be reserved with considerable length in the axial direction. Second, the bearing, steel sleeve, sensor rotor and stator are all independent components, which increases the number of parts, assembly complexity, and overall cost and weight. Thirdly, the space in the radial direction of the rotor (close to the bearing), due to the need to accommodate the bearing and sensor, is usually idle or underutilized, while the electronic control unit can only be arranged externally, further increasing the axial envelope size of the entire machine. For application scenarios where installation space is increasingly limited (such as hybrid electric vehicles), this design with a large axial size seriously limits the compatibility and layout flexibility of the electric machine.

[0005] Therefore, there is an urgent need for a new highly integrated electric machine structure that can effectively reduce the axial space occupation. SUMMARY

[0006] The purpose of the present application is to provide a highly integrated electric machine to solve at least one of the above technical problems.

[0007] To achieve the above purpose, the technical solution adopted by the present application is: A highly integrated electric machine, comprising: a housing with a mounting cavity; a stator assembly mounted in the mounting cavity; a rotor assembly coaxially mounted in the stator, the rotor assembly comprising a rotor support and a rotor core, the rotor support comprising a mounting sleeve and a connecting member, the rotor core being fixedly arranged on an outer wall of the mounting sleeve, the connecting member being arranged inside the mounting sleeve and close to an axial side of the mounting sleeve, the connecting member being connected with a crankshaft of an engine; an end surface of an end of the housing away from the connecting member is concave to form an inner recess extending into the mounting sleeve, the inner recess having a receiving space therein for mounting an electronic control.

[0008] Preferably, an axial length of the connecting member is less than half of an axial length of the mounting sleeve.

[0009] Preferably, gaps are left between the inner recess, an inner wall of the mounting sleeve and the connecting member.

[0010] Preferably, the connecting member comprises a flange plate, the flange plate being connected with the crankshaft of the engine by bolts.

[0011] Preferably, the connecting member comprises a rotor shaft, the rotor shaft being connected with the crankshaft of the engine.

[0012] Preferably, the rotor shaft is a spline shaft, the spline shaft being connected with the crankshaft of the engine.

[0013] Preferably, the rotor shaft is a smooth shaft, the smooth shaft being connected with the crankshaft of the engine by a coupling.

[0014] Preferably, the mounting sleeve and the connecting member are integrally formed.

[0015] Preferably, the connecting member is structurally optimized to improve running stability, the structural optimization comprising strength simulation optimization, vibration simulation optimization and NVH simulation optimization.

[0016] Preferably, the motor estimates back electromotive force and flux linkage according to a mathematical model to calculate a relative angle between the stator assembly and the rotor assembly, the mathematical model comprising a fundamental wave model in an αβ coordinate system.

[0017] Compared with the prior art, the present application has the following advantages: (1) The present application directly connects the rotor assembly with the crankshaft of the engine through the connecting member inside the rotor assembly by canceling the bearings and independent bearing sleeves arranged away from the output end of the conventional motor and canceling the physical position sensor (such as eddy current or rotary transformer) and its mounting structure, thereby greatly reducing the axial space required for the rotor assembly itself and its cooperation with the housing.

[0018] (2) The application creatively designs the end face of one end of the motor shell as inwardly recessed, forming an inward recess extending into the inside of the mounting sleeve, the inward recess has a containing space which can make full use of the space in the mounting sleeve not occupied by the connecting piece. The containing space can be used to install the electric control wholly or partially, realizing the high integration of the electric control and the motor body. This avoids the extra axial size caused by the external electric control, significantly shortening the axial envelope length of the whole machine.

[0019] (3) Through the above structural optimization, not only the axial size and the overall weight of the motor are effectively reduced, but also the number of parts (such as bearings, steel sleeves, sensor components) is reduced, thereby simplifying the assembly process and reducing the material cost and manufacturing cost. The compact structure of the motor makes it easier to adapt to the installation environment with limited space.

[0020] (4) The software algorithm based on the mathematical model of the motor (such as the fundamental wave model in αβ coordinate system) is used to estimate the back electromotive force and flux linkage, and then calculate the relative angle of the stator and rotor, replacing the traditional physical sensor. This not only saves the cost and space of the sensor itself, but also avoids the precision problems and potential failure points caused by sensor installation, improving the integration and reliability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a cross-sectional view of the highly integrated motor in the embodiment; Figure 2 is a cross-sectional view of the rotor support in the embodiment; Figure 3 is a side view of the rotor support in the embodiment; Figure 4 is a cross-sectional view of the shell in the embodiment; Figure 5 is a cross-sectional view of the motor in another preferred scheme in the embodiment; In the figure: 1, shell; 11, mounting cavity; 12, inward recess; 121, containing space; 13, A end; 14, B end; 2, stator assembly; 3, rotor assembly; 31, rotor support; 311, mounting sleeve; 312, connecting piece; 3121, flange; 3122, rotor shaft; 32, rotor core. DETAILED DESCRIPTION

[0022] The technical solutions of the present application will be described clearly and completely below with reference to the accompanying drawings. The following embodiments are exemplary and are used to explain the present application, but cannot be interpreted as a limitation on the present application. In the following description, the same reference signs are used to represent the same or equivalent elements, and repeated descriptions are omitted.

[0023] In the description of the present application, it should be understood that the terms "upper", "lower", "inner", "outer", "left", "right", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, or the orientation or positional relationship commonly understood by those skilled in the art, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the prepositions "first", "second", "third" and the like are only used for the purpose of distinguishing the objects being modified, and cannot be understood as indicating or implying relative importance.

[0024] In addition, the terms "mounting", "connecting", "connecting" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0025] It should be further understood that the term "and / or" used in the present application specification and corresponding claims means any combination of one or more of the listed items and all possible combinations.

[0026] As shown in Figures 1-4 The present embodiment provides a highly integrated motor. The motor includes a housing 1, a stator assembly 2, and a rotor assembly 3. The housing 1 is generally cylindrical in structure, and defines a cylindrical mounting cavity 11 inside. For the convenience of description, the end of the housing 1 close to the engine is defined as the A end 13, and the opposite end is defined as the B end 14.

[0027] The stator assembly 2 is fixedly installed in the mounting cavity 11 of the housing 1. The stator assembly 2 includes a stator core and a stator winding (not shown in detail), which is similar in structure to the stator of a conventional permanent magnet synchronous motor or induction motor, and is fixed to the inner wall of the housing 1 by interference fit, bolts or press fitting, etc.

[0028] The rotor assembly 3 is coaxially arranged inside the stator assembly 2. The rotor assembly 3 includes a rotor support 31 and a rotor core 32 fixed on the rotor support 31. The rotor core 32 usually has permanent magnets (for permanent magnet synchronous motor) or cast conductive bars (for induction motor) installed thereon.

[0029] One of the core improvements of the present application is the structure of the rotor assembly 3. Specifically, the rotor support 31 comprises a cylindrical mounting sleeve 311 and a connecting piece 312. The rotor core 32 is fixedly sleeved on the outer wall of the mounting sleeve 311, for example by heat shrinkage, key connection or adhesion. The connecting piece 312 is arranged in the internal cavity of the mounting sleeve 311, and its position is close to the axial side (i.e. the A end 13) of the mounting sleeve 311. The connecting piece 312 is used to connect with an external power source, such as the crankshaft of an engine, so as to transmit the power of the engine to the rotor, or output the power of the motor to the engine (as a generator or booster motor).

[0030] Exemplarily, as shown in Figures 1-3 In this embodiment, the connecting piece 312 is specifically a flange plate 3121. The flange plate 3121 can be fixed inside the A end 13 of the mounting sleeve 311 by welding, bolt connection or one-piece forming, preferably one-piece forming. The flange plate 3121 is provided with a plurality of bolt connection holes. The end of the engine crankshaft is also usually provided with a corresponding flange plate 3121, and the rigid coaxial direct connection between the rotor assembly 3 and the engine crankshaft can be achieved by passing a plurality of bolts through the bolt connection holes of the two and tightening. This connection mode has large torque transmission and good centering.

[0031] As shown in Figure 1 and Figure 4 Another core improvement of the present application is the structure of the B end 14 of the housing 1. The B end 14 of the traditional motor housing 1 is usually flat or has a boss to install the bearing seat, while in the present application, the end face of the B end 14 of the housing 1 is recessed inward (i.e. into the mounting cavity 11), forming an inner recess 12. The inner recess 12 extends axially into the motor interior, with its end extending into the internal space of the mounting sleeve 311 of the rotor assembly 3. The inner recess 12 itself encloses an independent accommodation space 121.

[0032] The accommodation space 121 is used to install the electric control, i.e. the electric control unit. The electric control unit is used for the control of the motor, and usually contains power devices (such as IGBT modules), control circuit boards, drive circuits, sensor interfaces, power management, etc. In the traditional design, the electric control unit is usually installed as an independent component outside the motor, or on the outside of the end of the motor housing 1, which undoubtedly increases the axial length of the entire drive system. The present application installs the electric control unit wholly or partially into the accommodation space 121 by the inner recess design of the housing 1, so as to utilize the space inside the mounting sleeve 311 and realize high integration in physical space. The electric control unit can be fixed in the accommodation space 121 of the inner recess 12 by means of a bracket, a bolt or a buckle, etc. Its wire harness can be led out through the pre-set wire hole (not shown in the figure) of the housing 1. This design greatly improves the utilization rate of the internal space of the motor, and is the key to shorten the axial size of the entire machine.

[0033] Further, the axial length of the connecting member 312 is less than half of the axial length of the mounting sleeve 311. The connecting member 312 is mainly concentrated in the A end 13 part of the mounting sleeve 311, leaving enough internal space for the B end 14 to form the accommodating space 121.

[0034] Further, gaps are left between the wall surface of the inner recess 12 and the inner wall of the mounting sleeve 311, and between the end surface of the inner recess 12 and the connecting member 312, to prevent the rotating mounting sleeve 311 from colliding or rubbing against the stationary inner recess 12 due to the rotor's slight radial runout or axial movement during motor operation. The size of the gap needs to be determined comprehensively according to factors such as the design accuracy, expected deformation, and thermal expansion of the motor.

[0035] As another preferred aspect of the present embodiment, as shown in Figure 5 The connecting member 312 can be a rotor shaft 3122. The rotor shaft 3122 can be fixed to the mounting sleeve 311 by key connection, interference fit, or welding, etc. More preferably, the mounting sleeve 311 and the connecting member 312 (rotor shaft 3122) are integrally formed, for example, by casting or forging process to make a whole rotor support 31 part. Integrally forming can ensure higher coaxiality and structural strength, reducing assembly steps and potential imbalance sources.

[0036] Exemplarily, the rotor shaft 3122 can be a spline shaft. The end of the spline shaft is processed with external spline teeth. Correspondingly, the end of the engine crankshaft is processed with internal spline holes (or through a transition sleeve). Through spline fitting, synchronous rotation and torque transmission of the rotor assembly 3 and the engine crankshaft can be achieved, while allowing a small amount of axial relative displacement, which is beneficial for compensating for installation errors or thermal expansion and contraction.

[0037] As another preferred aspect of the present embodiment, the rotor shaft 3122 can also be a smooth shaft. The end of the smooth shaft is a smooth cylindrical surface without spline. At this time, the smooth shaft needs to be connected with the engine crankshaft through a coupling. The coupling can be a rigid coupling (such as sleeve type, flange type), or a flexible coupling (such as diaphragm type, elastic pin type). The flexible coupling can better compensate for the radial, angular, and axial deviations between the two shafts, absorb vibration and impact, and is beneficial for improving the system NVH performance.

[0038] Because this invention eliminates the bearing used to support the rotor in a traditional motor (the bearing located at end B 14 of the motor), this structural change places higher demands on the structural strength and dynamic characteristics of the rotor assembly 3, especially the connector 312 and the mounting sleeve 311 connected to it. To ensure the smoothness, reliability, and durability of the motor operation, specialized structural optimization is required for the connector 312 (and the rotor support 31 in which it is located). This structural optimization includes, but is not limited to, strength simulation optimization, vibration simulation optimization, and NVH simulation optimization.

[0039] Strength simulation optimization includes: establishing a finite element model of the rotor support 31 (including mounting sleeve 311 and connector 312), applying loads such as the maximum torque that the engine may transmit, axial force, and centrifugal force of the rotor itself, and performing static and fatigue strength analysis. The optimization goal is to achieve lightweight design through topology optimization, shape optimization, and other means, while meeting the material yield strength and fatigue safety factor. For example, local thickness or fillet (filling) can be added to the connection area (stress concentration area) of flange 3121 (when connector 312 is flange 3121), and thinning or weight reduction holes can be added to non-critical stress areas (such as the part of mounting sleeve 311 near motor B end 14). High-strength cast iron (such as QT400 to QT700 series ductile iron) or forged steel can be selected as the material to balance strength, cost, and machinability.

[0040] Vibration simulation optimization includes: performing modal analysis on the optimized rotor assembly 3 to calculate its natural frequencies and mode shapes, ensuring that its operating speed is far from the critical speeds of each order, and avoiding resonance. Random vibration simulation and swept-frequency vibration simulation are performed to simulate various road surface excitations and engine vibration excitations encountered by the motor during vehicle operation, evaluating the stress response and deformation of rotor assembly 3 under these dynamic loads, and further verifying its structural reliability.

[0041] NVH simulation optimization includes: establishing a more complex system model that includes the motor, connector 312, and part of the engine structure, and performing NVH (noise, vibration, and harshness) simulations. Modal analysis and frequency response analysis are used to evaluate the vibration and noise performance of the motor under electromagnetic force and mechanical unbalanced force excitation. The stiffness and mass distribution of rotor assembly 3 are optimized to reduce vibration and noise at specific orders, thereby improving overall vehicle comfort.

[0042] The aforementioned simulation optimization process is typically combined with physical testing for verification. An optimized rotor prototype is manufactured, subjected to strength and vibration durability tests on a test bench, and then mounted on a vehicle for NVH (Noise, Vibration, and Harshness) measurements under various operating conditions. Through iterative iterations, a rotor assembly structure 3 that meets both spatial integration requirements and possesses excellent mechanical and NVH performance is ultimately obtained.

[0043] Another important feature of this invention is the elimination of physical position sensors (such as eddy current sensors or rotary transformers). This further reduces the number of parts, cost, and axial space occupation, and improves system reliability.

[0044] The motor estimates the back EMF and flux linkage based on the mathematical model of the permanent magnet synchronous motor, thereby calculating the relative angle (i.e., rotor position angle) between the stator assembly 2 and the rotor assembly 3.

[0045] For example, the mathematical model used can be a fundamental wave model of the motor built in the αβ stationary coordinate system. Control algorithms (such as model reference adaptive, sliding mode observer, extended Kalman filter, etc.) sample the three-phase stator voltage and current of the motor in real time. After coordinate transformation, a back EMF observer or flux observer is constructed using the voltage equation and flux linkage equation of the motor in the αβ coordinate system. By performing appropriate mathematical processing (such as phase-locked loop technology) on the estimated back EMF or flux linkage signal, the rotor position and speed information can be extracted.

[0046] It should be noted that although the present invention has been disclosed above with specific embodiments, the above embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A highly integrated electric machine characterized by, The utility model relates to a motor with a mounting cavity, a stator assembly mounted in the mounting cavity, and a rotor assembly coaxially mounted in the stator, the rotor assembly comprising a rotor support and a rotor core, the rotor support comprising a mounting sleeve and a connecting piece, the rotor core being fixedly arranged on the outer wall of the mounting sleeve, the connecting piece being arranged inside the mounting sleeve and close to the axial side of the mounting sleeve, and the connecting piece being connected with the engine crankshaft. The end surface of the housing away from the connecting piece is concave to form an inner recess extending into the mounting sleeve, and the inner recess has a containing space for mounting an electronic control. The axial length of the connecting piece is less than half of the axial length of the mounting sleeve. Gaps are left between the inner recess, the inner wall of the mounting sleeve, and the connecting piece. The connecting piece comprises a flange plate connected with the engine crankshaft through bolts.

2. A highly integrated electric machine as claimed in claim 1, characterized in that The connecting piece comprises a rotor shaft connected with the engine crankshaft.

3. A highly integrated electric machine as claimed in claim 1, characterized in that The rotor shaft is a spline shaft connected with the engine crankshaft.

4. A highly integrated electric machine as claimed in claim 1, characterized in that, The rotor shaft is a smooth shaft connected with the engine crankshaft through a coupling.

5. A highly integrated electric machine as claimed in claim 1, characterized in that, The mounting sleeve and the connecting piece are integrally formed.

6. A highly integrated electric machine as claimed in claim 5, characterized in that The connecting piece is optimized in structure to improve the running stability, the structural optimization including strength simulation optimization, vibration simulation optimization, and NVH simulation optimization.

7. A highly integrated electric machine as claimed in claim 5, characterized in that The motor estimates counter electromotive force and flux based on a mathematical model to calculate the relative angle between the stator assembly and the rotor assembly, the mathematical model including a fundamental model in the alpha-beta coordinate system.

8. A highly integrated electric machine as recited in claim 1, wherein, ​ 9. A highly integrated electric machine as recited in claim 1, wherein, ​ 10. A highly integrated electric machine as claimed in claim 1, characterized in that, ​

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