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Power Transmission, Brakes and Cooling Systems
Published in Iqbal Husain, Electric and Hybrid Vehicles, 2021
The disk brakes are the preferred choice for both front and rear wheels of passenger vehicles. The pads of the disk-type brakes are forced against the machined surfaces of a rotating disk called the rotor which is attached to the wheel. The disk brakes have friction pads controlled by a caliper arrangement, which when engaged clamps to the rotor and the wheel. The brake pads are designed to assist cooling and resist fading. Fading causes the braking friction coefficient to decrease with temperature rise. The high force required for caliper actuation is typically supplied from a power assist device following the brake command input from the driver.
Running gear and braking
Published in Andrew Livesey, Motorcycle Engineering, 2021
Brake fluid is a special type of oil developed to give the specific properties needed by the braking system. These are:High boiling point to reduce the risk of brake fadeNoncorrosive to rubber and the other materials used in the braking systemLubricating properties for the mating partsWill not fail under very high pressureLow viscosity for rapid response to pedal operation
Chassis systems
Published in Tom Denton, Advanced Automotive Fault Diagnosis, 2020
Drum brakes operate by shoes being forced onto the inside of the drum (Figure 7.4). Shoes can be moved by double- or single-acting cylinders. The most common layout is to use one double-acting cylinder and brake shoes on each rear wheel of the vehicle, and disc brakes on the front wheels. A double-acting cylinder simply means that as fluid pressure acts through a centre inlet, pistons are forced out of both ends.
Experimental analysis of the heat transfer generated during the operation of an automotive disc brake
Published in Australian Journal of Mechanical Engineering, 2023
R. A. García-León, G. Guerrero-Gómez, N. Afanador-García
Disc brakes are fundamental elements to maintain manoeuverability and, above all, safety in any vehicle, whether it is rotary or linear, and that of its occupants. Braking systems work by taking advantage of friction to slow down the moving vehicle through mechanical contact between two surfaces (pad and disc brake). There are currently various types of brakes, depending on the application: drum, band, disc, and conical. In particular, for the automotive sector, the most common is the disc auto-ventilated type in the front part and the drum type in the rear part (García-León, Flórez-Solano, and Acevedo-Peñaloza 2018; Asim 2014). Disc brakes differ from other types in that the applied force is normal to the disc herd and not radial, as in drum and band brakes. Another characteristic is that the friction moment does not help the actuation moment (self-energising effect), as occurs in drum and bevel brakes. This behaviour allows slight changes in the friction coefficient not to affect the braking force required to dramatically stop the car. For example, a 30% variation in the friction coefficient, which is a normal condition in humid environments, causes an increase in the force of 50%. That behaviour is why the disc brakes have occupied an important place in the automotive industry, especially in the commercial vehicle market (Wahlström 2011; Blau 2001).
CFD-aided approach of modelling and dynamic characteristic optimization for a highly nonlinear auxiliary braking system
Published in Engineering Applications of Computational Fluid Mechanics, 2022
Konghua Yang, Xichun Guan, Xiaoli Zhang, Chunbao Liu
Heavy-duty vehicles are an important transport means and are widely used to deliver people and goods over long distances, such as in public transportation (Bravo et al., 2018; Broniszewski & Piechna, 2019; Kumar & Rajagopal, 2020). In China, 31% of the length of highways passes through and over mountains, hills, and plateaus, and therefore, have long downhill sections (Qian et al., 2020). Most of the commercial trucks are heavy-duty vehicles and need high braking power while slowing over a long distance. Traditional frictional braking transforms the kinetic energy into heat energy, which can cause brake fade; this not only is a safety risk but also prevents energy recovery and reuse (Xu & Cai, 2020; Ye et al., 2019; Yevtushenko et al., 2015). The braking system of a heavy-duty vehicle requires a high braking torque and quick response time, and it must be able to handle the frequent starts and stops as the vehicle travels at full speed and along downhill sections. It is difficult for traditionally available braking systems to simultaneously fulfil all of these requirements.
Tribo-mechanical performance of brake composite material: a comprehensive review
Published in Tribology - Materials, Surfaces & Interfaces, 2023
Dhinakaran Veeman, Jitendra Kumar Katiyar, Alessandro Ruggiero
Moreover, the different materials and their effect on brake efficiency are discussed. These brakes are classified into several types based on the mode of operation and the direction of forces acting. Based on the method of operation, they are classified as, Hydraulic brakes, Air brakes and Magnetic brakes. Based on the direction of forces working, they are classified as Radial brakes and axial brakes. Hydraulic brakes use fluid power to transfer pressure from a controlled mechanism to a mechanical one. These brakes are very efficient and depend on fluid properties, material characteristics, etc. [16,17].