【導(dǎo)讀】盤式制動(dòng)器主要用于行車制動(dòng)，其制動(dòng)效能穩(wěn)定，在汽車中得到廣泛的應(yīng)用。本設(shè)計(jì)通過對(duì)摩擦片的中心圓半徑、摩擦片直徑、制動(dòng)盤的直徑、活塞直徑、制動(dòng)盤。優(yōu)化設(shè)計(jì)目標(biāo)，建立盤式制動(dòng)器的優(yōu)化設(shè)計(jì)數(shù)學(xué)模型。選用合理的優(yōu)化設(shè)計(jì)方法，編寫

　　

【正文】 System for Commercial Vehicles The ABS prevents the wheels from locking when the vehicle is overbraked. The vehicle therefore retains its directional stability and steerability even under emergency braking on a slippery road surface. The stopping distance is often shorter as opposed to braking with locked wheels. In contrast to passenger cars, mercial vehicles have pneumatic braking systems. Nevertheless, the functional description of the ABS control circuits for passengers cars applies also to mercial vehicles. The antilock braking system as used in mercial vehicles consist of wheelspeed sensors, an electronic controller and pressuremodulation valves. The ABS regulates the brake pressure in each brake cylinder by increasing the pressure, holding it constant or by reducing it by exhausting to atmosphere. The brake pressure can be controlled individually for each wheel. Under split conditions (different friction coefficients between righthand and lefthand wheels, . black ice at edge of road surface, good grip at center of road surface) braking produces a high yawing moment about the vertical axis of the vehicle: this is coupled with a high steering moment as a result of the positive steering roll radii in mercial vehicles. Vehicles with a short wheelbase are thus difficult to control. Therefore, in the case of unequal friction coefficients on right and left, the yawing and steering moments are limited by a modified control at the steering axle. The difference in brake pressure between the righthand and lefthand braking cylinders does not exceed an allowable value. Depending on the number of controlled axles, there are 2wheel and 6wheel ABS systems available in order to be able to optimize the equipping of the various models of mercial vehicle in terms of performance and cost. 2wheel systems are used predominantly for semitrailers with 2wheel, 4wheel or 6wheel units. The wheels on each axle are individually controlled. Further axles receive the same braking pressure as the controlled axle. 4wheel systems are used in 4wheel buses, trucks and trailers as well as in 6wheel vehicles with 4wheel unit, the axles of which can be served with one control circuit. 6wheel systems are intended mainly for vehicles with a long wheelbase, . articulated buses. All systems can be equipped with singlechannel or twochannel pressuremodulation valves. With the engine brake or retarder on, the ABS monitors brake slip and regulate it within the allowable range by switching the retarder on and off. In the mercial vehicles with pneumatic/hydraulic converters, . for disk brakes, the 吳?。恨I車盤式制動(dòng)器設(shè)計(jì)及優(yōu)化 18 ABS allowable the pneumatic brake circuit. In vehicle binations, full equipping with ABS is the optimum, but even partial equipping with ABS (ABS in towing vehicle or trailer). Makes the vehicle bination easier to control. 1. Wheel Speed Sensor A wheelspeed sensor consists of a toothed pulse ring and an inductive wheelspeed pickup. The pulse ring is mounted on the hub and, as the wheel rotates, produces in the wheelspeed pickup an . voltage, the frequency of which is proportional to the wheel speed. The wheelspeed pickup is held in a mounting hole by a spring sleeve. When being installed in vehicle, it is pressed in until it es up against the pulse ring. As a result of the wheelbearing play and the elastic deformations of axle, it is pushed out by the pulse ring during driving, thus being automatically adjusted to the necessary gap. 2. Electronic Controller The electronic controller is basically of digital design and contains redundant microputers. From the signals from the wheelspeed pickups, these microputers calculate the wheel speeds as well as the wheel decelerations and accelerations. A vehicle reference speed is formed from the wheel speeds of two diagonally opposite wheels. With this reference speed and the individual wheel speeds it is possible to calculate the brake slip for each wheel. If a wheel has a tendency to lock, this is determined from the wheelacceleration and slip signals. In such a case, the microputer energize the mags of the pressuremodulation valves which control the brake pressure in the individual brake cylinders. The electronic controller contains a prehensive program for the diction of faults throughout the entire antilock system (wheelspeed sensors, controller, pressuremodulation valves, wiring harness). If a fault is detected, the controller switches off the defective part of the ABS. This is indicated by a warning lamp. The service braking system remains fully operational. To speed up troubleshooting in the workshop, it is possible to switch on the controller selfdiagnosis feature by pressing a button. A flashing diagnosis lamp then indicates the defective circuit. 3. Pressure Modulation Valve The pressuremodulation valve consist of the electromagic 3/2 pilot valve and the pneumatic 2/2 diaphragm valves, the latter being provided with sufficiently large cross sections. When the pilot valves are energized in suitable bination by the electronics, the “pressureholding/pressurereduction” functions are obtained. No energization means “pressure buildup”. During braking without the ABS ing into operation (wheels showing no signs of locking), the air flows unhindered in both directions through the valves during air admission to and exhausting of the brake cylinders. To minimize the costs of equipping the various types of vehicle with ABS, there are onechannel and twochannel versions of the pressuremodulation valve. The onechannel version is used predominantly in cases where the pressuremodulation valve has to be installed to the side of engine and transmission near the wheel. Thanks to its pact construction, the twochannel version permits centralized installation of the valve on an axle. This advantag