CN-122001116-A - Rotor assembly, electric drive assembly and control method of rotational inertia of rotor assembly

Abstract

The invention discloses a rotor assembly, an electric drive assembly and a control method of rotational inertia of the rotor assembly and the electric drive assembly, and relates to the technical field of motors. The invention aims to solve the problems of large radial runout and poor NVH performance caused by insufficient rotor moment of inertia in the prior art. The invention provides a rotor assembly, which comprises a rotating shaft and a rotor core body fixed on the rotating shaft, and is characterized by further comprising an inertia increasing part, wherein the inertia increasing part is fixedly arranged on the rotating shaft and extends along the radial direction of the rotating shaft. According to the invention, the inertia increasing part is additionally arranged on the rotating shaft, so that the rotational inertia of the rotor assembly can be effectively and controllably increased, the radial runout of the rotor in the working process is restrained, the NVH performance of the electric drive assembly is obviously optimized, and the operation reliability is improved.

Inventors

• HUANG MINGYE
• FU BO
• LI TING

Assignees

• 智新科技股份有限公司

Dates

Publication Date

20260508

Application Date

20260120

Claims (10)

1. 1. The rotor assembly comprises a rotating shaft and a rotor core body fixed on the rotating shaft, and is characterized by further comprising an inertia increasing part which is fixedly arranged on the rotating shaft and extends along the radial direction of the rotating shaft to improve the rotational inertia of the rotor assembly.
2. 2. The rotor assembly of claim 1 wherein the inertia increasing portion is a disk-like structure.
3. 3. The rotor assembly of claim 1 wherein the inertia increasing portion is of unitary construction with the rotating shaft.
4. 4. The rotor assembly of claim 1 wherein the inertia increasing portion is a separate component from the rotating shaft and is secured to the rotating shaft by an interference fit, shrink fit, welding, keying or spline connection.
5. 5. A rotor assembly as claimed in claim 1, wherein the radially outermost edge of the inertia increasing portion is provided with an additional weight.
6. 6. A rotor assembly as claimed in claim 5, wherein the additional weight is of an annular configuration protruding in an axial direction of the inertia increasing portion, and an axial thickness of the additional weight is greater than an axial thickness of the inertia increasing portion body.
7. 7. An electric drive assembly comprising a rotor assembly as claimed in any one of claims 1 to 6, wherein one end of a rotatable shaft of the rotor assembly is adapted to be connected to a crankshaft of an internal combustion engine and the other end is suspended.
8. 8. The control method of the rotational inertia of the rotor assembly is characterized by comprising the following steps: s1, determining a target rotational inertia value of the rotor assembly according to target NVH performance of the motor assembly; s2, providing a basic rotor structure comprising a rotating shaft and a rotor core; s3, arranging a radially extending inertia increasing part on the rotating shaft; S4, adjusting at least one geometric parameter of the inertia increasing part to enable the actual rotational inertia of the rotor assembly to reach or be close to the target rotational inertia value.
9. 9. The method of claim 8, wherein the step of adjusting at least one geometric parameter of the inertia increasing portion comprises adjusting a radial dimension of the inertia increasing portion.
10. 10. The method of claim 8, wherein the step of adjusting at least one geometric parameter of the inertia increasing portion further comprises providing an additional weight at a radially outermost edge of the inertia increasing portion and adjusting an axial thickness of the additional weight.

Description

Rotor assembly, electric drive assembly and control method of rotational inertia of rotor assembly Technical Field The invention relates to the technical field of motors, in particular to a motor rotor structure, and particularly relates to a rotor assembly with high rotational inertia, an electric drive assembly comprising the rotor assembly and a method for controlling the rotational inertia of the rotor assembly. Background In electric drive systems for new energy vehicles, such as hybrid or extended range vehicles, the generator is often designed to be directly connected to the crankshaft of the internal combustion engine. In this arrangement, the rotor assembly of the generator is typically connected to the crankshaft through one end of its rotating shaft, while the other end of the rotor assembly is suspended within the stator cavity without any support structure such as bearings. This single-ended cantilever structure places extremely high demands on the dynamic stability of the rotor assembly. However, conventional rotor designs tend to focus on electromagnetic performance and weight reduction, resulting in relatively small moment of inertia of their own. According to the law of rotation, a small moment of inertia means a rotor with a weak resistance to a change in rotation state, and its free end is liable to generate a large radial runout when subjected to torque pulsation or other external disturbance from the engine. This radial runout is one of the main causes of deterioration in NVH (noise, vibration and harshness) performance of the electric drive system. Under extreme working conditions, excessive radial runout may even cause scraping or collision (i.e. "sweeping") between the rotor and the stator, which causes irreversible damage to the motor and seriously affects the reliability and the service life of the power assembly. Therefore, a technical scheme capable of effectively improving the rotational inertia of the rotor assembly is urgently needed in the prior art, so that the technical problems of large radial runout, poor NVH performance and low operation reliability caused by insufficient inertia of the cantilever type rotor are solved. Disclosure of Invention Aiming at the problems of small rotor moment of inertia, large radial runout and poor NVH performance in the background technology, the invention provides a rotor assembly, an electric drive assembly and a control method of the moment of inertia thereof, and aims to remarkably improve the moment of inertia of the rotor assembly in a limited space by improving a rotor structure, thereby inhibiting the radial runout and optimizing the NVH performance. In order to solve the technical problems, in a first aspect, the invention provides a rotor assembly, which comprises a rotating shaft and a rotor core fixed on the rotating shaft, wherein the rotor assembly further comprises an inertia increasing part fixedly arranged on the rotating shaft and extending along the radial direction of the rotating shaft for improving the rotational inertia of the rotor assembly. By adopting the technical means of adding the radially extending inertia increasing part on the rotating shaft and utilizing the physical principle that the larger the moment of inertia is when the mass distribution is far away from the rotating center, the invention can directly and effectively increase the moment of inertia of the whole rotor assembly on the premise of not changing the electromagnetic design of the rotor core body, thereby enhancing the rotation stability of the rotor assembly, inhibiting radial runout and improving NVH performance. As a preferable mode of the present invention, the inertia increasing portion has a disk-like structure. Through designing inertia increase portion into discoid, provide a simple structure and efficient realization mode, can be in limited axial space, effectively distribute the position at keeping away from the rotation axis with the quality through great radial dimension, realize the high-efficient promotion of moment of inertia. As a preferable mode of the present invention, the inertia increasing portion and the rotation shaft are integrally formed. By adopting the integrated structure, the assembly clearance and potential coaxiality error are eliminated, and the extremely high structural rigidity and dynamic balance precision are ensured, so that the vibration generated under high-speed rotation is very important to be restrained, and the novel energy automobile structure is particularly suitable for new energy automobile application with severe requirements on smoothness and NVH performance. As a preferred embodiment of the present invention, the inertia increasing part is a member independent of the rotation shaft and is fixed to the rotation shaft by interference fit, shrink fit, welding, keying or spline connection. By adopting the split design, the requirements on the size of the rotating shaft blank and the processing diff