磁流變制動器效能分析

The performance analysis of a magneto-rheological brake

楊紹韡(Shao-Wei Yang)

指導教授 ： 許政行

中原大學/工學院/機械工程研究所/碩士(2014年)

https://doi.org/10.6840/cycu201400072

摘要

本研究採用磁流變流體(Magneto-rheological fluid，MRF)作為磁流變制動器之介質，藉由外加磁場改變其黏滯力，以增加工作表面積之剪力達到快速提升整體煞車力，並探討因其黏度導致的溫度變化。
　　本文首先釐清最佳制動力的條件與最佳制動力僅為特定車軸幾何尺寸和重量的函數。經由理論求解出最佳制動力正比於磁石長度的四次方，並推導動量方程式之解析解來驗證模擬之可靠性，配合田口方法搭配ANSYS Fluent做模擬分析，找出提升制動力矩及降低工作流體溫度之最佳因子組合。
　　多次實驗中，煞車未作動之條件下流體最小升溫的最佳因子組合為A2B3C3D3，測得模擬穩態溫度約為315K。
　　在多次實驗中最大制動力矩之最佳因子組合為A1B3C1D1，測得模擬制動力矩約為269 N-m。
　　在所有實驗中以間隙大小與磁石長度對整體的影響力最具貢獻。模擬也針對最終最佳組合進行煞車時的溫升變化及釋放煞車後的溫降變化，得出在溫升限制之上限情況下，每一煞車循環之最大週期為21.4秒，而在週期中第3.6秒為最高溫之上限。

關鍵字

田口方法 ； 磁流變流體

並列摘要

In order to raise the brake forces, this research takes Magneto- rheological fluid (MRF) as the media of magneto-rheological brake. The varying of its viscosity by adding magnetic field will make shear force raise by working area adding, which will make brake forces raise faster, and investigate the varying of temperature by its viscosity.

In the beginning, the optimal condition of braking force is just particular vehicles function of geometry size and weight. By theory, the optimal of braking force and magnet length to the fourth power are directly proportional, and deriving an exact solution from momentum equations verifies the reliability of the simulation. By using Taguchi method and ANSYS Fluent to simulate and analyze, the optimal factors of the raising of the braking torque, and the reducing of the temperature of the working fluid (MRF).

Considering the cases of the brake without undoing, we obtained a minimum fluid temperature rising, and this optimal factors combination was A2B3C3D3, and it was shown that the minimum temperature under steady state was 315 K.

For the cases of maximum torque, the obtained result was A1B3C1D1, and it was shown that the maximum torque was 269 N-m.

For all cases of experiments, it was found that the most influential contributions among the all factors were gap and magnet length. The simulation of the temperature from braking to release braking by using the final optimal factors combination got a maximum period, which is a cycle by each brake is 21.4 seconds with temperature raising, which is at the top of temperature limit, and at three-point-sixth second in the period has upper limit of temperature.

並列關鍵字

Magneto-Rheological Fluid ； Taguchi Method

參考文獻

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