Study on Oil Viscosity-time Model and Braking Characteristics of Electro-hydraulic Brake in Cold Regions
Aiming at the sliding problem of the brake system caused by insufficient braking force and braking torque of the electro-hydraulic brake in the cold regions,based on the oil Vogel viscosity-temperature model and the local temperature change datas,an oil viscosity-time model was constructed.Based on this model,the electro-hydraulic brake oil flow characteristics in the braking process are studied.Then the braking performance of the electro-hydraulic brake is quantitatively analyzed.The results show that in the braking process,the hydraulic oil pressure of the electro-hydraulic brake is mainly distributed in the piston bottom cavity,and increases gradually with the increase of the viscosity.When the oil viscosity is 662.4 Pa·s,the pressure reaches 1.455 × 10-3 MPa.The eddy circulation of the hydraulic oil appeared in the impeller central shaft,whose intensity gradually increases with the increase of the viscosity.Under the given working conditions,the minimum braking force and braking torque of the electro-hydraulic brake are 1098 N and 274 N·m,respectively.This braking torque is lower than the working torque range of the electro-hydraulic brake.Therefore,the braking force and braking torque can be improved by replacing the hydraulic oil with smaller viscosity in the month or adding a pre-heating system,so as to realize normal braking.
electro-hydraulic brakecold regionsviscosity-time modelflow field characteristicbraking characteristic
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