Brake squeal has high frequency and high intensity which may greatly affect the driving comfort, and it has long been a major concern for the mechanical engineering. A mature test method for brake squeal has been established in existing research in straight line travel. However, the method cannot solve the problem of brake squeal in steering condition recently discovered by enterprises. This deteriorates driving experience in the urban traffic environment which would bring economic losses to the enterprises. In this paper, the road test method is used to reproduce the steering brake squeal. The noise signal and the component acceleration signals are collected in the test, and the acoustic vibration characteristics of the steering brake squeal are analysed. The squeal frequency is 2344Hz and is consistent with component vibration frequency. In addition, the six-component forces of front wheels, the steering wheel angle, the brake pressure are measured, and the occurrence condition of the steering brake squeal is determined as the low brake pressure, the steering wheel turning right 5/4 laps, and the wheel speed between 20-0r/ min. At the same time, the differences of the six-component forces of the wheel under different steering angles and brake pressures are compared. It is found that the change of the lateral force, roll and returning moment caused by the steering may be the cause of the steering brake squeal. This paper lays the foundation for further research on steering brake squeal.

Recycling of brake pads is a tough but promising work considering the current end of lifecycle. This study assesses the environmental performance of brake pads made up of recycled friction materials in terms of energy use, CO2 footprint and airborne particle number. Energy use and CO2 footprint are calculated with the data from CES Edupack and airborne emission particle number is measured on a pin-on-disc tribometer. The results demonstrate that recycled pads show better performance on energy consumption and CO2 footprint than virgin pads. These credits primarily come from raw material savings since recycled friction materials involve much less manufacturing processes than virgin ones. The experiment shows that the average airborne particle number of the recycled pad is greater than virgin ones, accompanied by a large scatter. Some more research works are still required to assess the airborne particle emission performance of recycled pads.

The friction brake is an extremely important part of vehicle assembly, and is responsible mainly for safety. From one side it is relatively cheap to manufacture and simple as a mechanical design, on the flip side final customers have a very high expectation related to quiet operation, good pedal feeling, environmental protection and fuel saving. A typical brake pad is made of quite a few different elements, but one of the most important is its back-plate. It plays the crucial role of the skeleton on which piston forces are focused. Usually for the production of the metal supports of the brake pads for passenger cars and light vans very low-grade steel is used, because it is cheap to produce and its mechanical properties are sufficient. However it does not mean that quality of this element can be completely omitted. n this paper we show the influence of basic properties of steel back-plate such as: flatness, deviation from tolerances, type of the steel used in the production and the type of blanking on NVH, pedal feeling and residual torque. The tests will be carried out under controlled conditions on a full scale inertia dynamometer.