Transmission durability test bench for new energy vehicles is mainly used for fatigue life test and performance test of reducer / transmission assembly of electric vehicles (including transmission shift performance test, gear transmission efficiency test, transmission vibration and noise test, transmission temperature characteristic test and transmission sealing performance test, etc.).
The test bench has the following three important characteristics.
(1) High speed compared with the traditional automatic and manual fuel vehicle transmission, high speed is the biggest feature of the reducer / transmission of new energy vehicles. The speed of the driving motor of the test bench shall not be less than 15000 R / min, which belongs to the highest speed demand in the automobile transmission test bench. Therefore, the key to the development of the test-bed is to precisely design and optimize the overall structure of the test-bed through the high-speed rotating shaft, reduce the excitation energy of the test-bed and improve the vibration absorption and anti vibration ability of the test-bed, so as to ensure that the test-bed will not produce resonance and low amplitude under forced vibration in all test speed ranges.
(2) High precision this kind of test-bed generally needs to carry out performance tests such as efficiency, so the requirements for torque and speed measurement accuracy and control accuracy are high.
(3) High reliability, because the transmission durability test bench needs 24h × 7d continuous operation, so unattended high reliable continuous operation performance is the key. Therefore, it is necessary to have a solid technical foundation and engineering experience in the reliability assurance of mechanical system, electronic control system and software system.
As shown in the figure, the durability test bench of new energy vehicle reducer / transmission assembly is developed by a well-known domestic gear transmission system test equipment development unit for a domestic third-party testing organization.
The test bench represents the advanced level of the transmission test bench of new energy vehicles in China. The key technologies are as follows.
1) Optimize the structural layout to ensure the high reliability of the test-bed. Fully consider the technical characteristics of high-speed input end and low-speed output end. For high-speed input end, realize high rigid design, simple structure, which is conducive to restraining high-frequency vibration.
2) Through simulation analysis, the anti vibration design of the mechanical system of the test-bed is realized. At the beginning of the scheme design, CAE simulation analysis software is used to analyze the strength, stiffness, vibration mode and vibration absorption capacity of key components, such as the high-speed shafting at the driving end, so as to improve the rotation accuracy, dynamic balance level, platform and base structure and weight of the high-speed shafting. Therefore, it can be realized: effectively avoid the resonance area and ensure that the shafting of the test-bed will resonate; Reduce the forced vibration excitation force caused by imbalance; Reduce the overall vibration response of the test-bed and its impact on surrounding facilities.
3) Precision design and manufacture of high-speed rotary shaft. For 15 000 R / min high-speed spindle, the rotation accuracy will be guaranteed to be ≥ 0.005mm and higher.
4) High rigidity design of motor support. In order to ensure the high anti vibration performance of the test-bed, the support of high-speed drive motor is designed as an integrated structure.