Magnetic powder two-speed transmission for new energy electric vehicles and its shifting method

Abstract

The invention discloses a magnetic powder type two-gear speed changer for a new energy electric automobile and a gear shifting method thereof. The magnetic powder two-gear speed changer comprises a shell body. A first salve gear, a magnetic power clutch, a second slave gear and a magnetic power brake which are connected sequentially are arranged in the shell body. A planet gear structure is further arranged in the shell body and comprises a planet frame. The two ends of the planet frame are connected with two planet wheels or four planet wheels correspondingly. A sun wheel is connected between the planet wheels. The magnetic powder type two-gear speed changer further comprises a gear ring. One side of the gear ring is engaged with the planet wheel, and the other side of the gear ring is engaged with the second slave gear. The planet frame is engaged with the first slave gear through a gear. The controlling method comprises a gear shifting pattern shifting gears from a low-speed gear to a high-speed gear and a gear shifting pattern shifting the gears from a high-speed gear to a low-speed gear. The working slip frequency interval between the electromagnetic brake and the electromagnetic clutch is small, the rapid corresponding characteristics of the electromagnetic brake and the electromagnetic clutch are combined, the heat productivity of the whole speed changer is low, and reliability is high.

Description

technical field [0001] The invention relates to a magnetic powder two-speed transmission for new energy electric vehicles and a gear shifting method thereof, belonging to the technical field of automatic gear shifting of electric vehicles. Background technique [0002] According to the applicant's knowledge, with the development of the economy, the environmental problems are becoming more and more severe, and pure electric vehicles have been widely used in recent years because of their zero-emission characteristics. The motor direct drive system has the advantages of stable operation and no power interruption. However, electric vehicles adopt a first-gear speed ratio, and the motor cannot always work in the high-efficiency range, especially under low-speed start-up and high-speed operation conditions. [0003] Therefore, electric vehicles began to adopt multi-speed transmissions, so that electric vehicles can work in a high-efficiency range. Taking two-speed transmissions as...

AI Technical Summary

Problems solved by technology

The motor direct drive system has the advantages of stable operation and no power interruption, but the electric vehicle adopts a first-gear speed ratio, and the motor cannot always work in the high-efficiency range, especially in low-speed start-up and high-speed operation conditions

[0003] Therefore, electric vehicles began to adopt multi-speed transmissions, so that electric vehicles can work in a high-efficiency range. Taking two-speed transmissions as an example, the existing two-speed transmissions mostly follow the traditional transmission scheme. The first transmission scheme is: use a synchronizer and hydraulic clutch scheme, this kind of transmission has the problems of shift shock, low clutch reliability and large volume

The second transmission scheme is: the scheme of electromagnetic clutch, the existing problems are as follows: 1. The clutch is mostly installed in the axial direction. Due to the working principle and end effect of the electromagnetic brake, the electromagnetic brake is easy to have an impact on the planetary gear transmission mechanism. , the service life is reduced; 2. The axially installed electromagnetic clutch is installed on the rotating parts, which is not conducive to heat dissipation. The electromagnetic clutch often has a large margin and the working environment is harsh, resulting in a decrease in the life and reliability of the entire transmission; 3. The magnetic powder clutch belongs to It is a kind of electromagnetic clutch, and in the existing scheme of using magnetic powder clutch, the heating of the magnetic powder clutch mainly comes from the slip power generated by the clutch under the slip condition, and the slip condition of the magnetic powder clutch generally lasts for It is about 1s, and the torque output of the magnetic powder brake has a certain hysteresis. The response time of the torque output step-down is shorter than the step-up response time. The speed response of the traditional engine is slow, resulting in slippage during the shifting process. The differential power is basically borne by the magnetic powder clutch, resulting in a large loss of the transmission

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