Windscreen Wash / Wipe Systems Topics covered in this presentation: Front and Rear Wiper Systems Washer Systems and Components Self Park and Automatic Speed Adjust Systems

The Wiper System Windscreen wipers are designed to keep the windscreen clear. They remove substances such as water, ice, mud and snow. Windscreen Wiper arm and blade The wiper system consists of wiper arms and blades, an electric (wiper) motor and mechanical linkages. The wiper arms are moved by the wiper motor, via the linkage mechanism. Linkages Wiper motor The wiper system is robustly made and very reliable. The rubber wiper blades are the only consumables. Reservoir

The Wiper Motor The wipers are driven by permanent magnet DC motors. Rotating arm Gears Rubber grommet The wipers are driven by permanent magnet DC motors. The end of the motor shaft is fitted with a worm gear that drives a series of output gears (compound gear train) to achieve a high torque ratio. The motor and gears are incased in a metal or plastic case, with hard packed lubricating grease for smooth lengthy running. Rubber grommets fix the motor to the vehicle chassis to prevent vibrations and noise.

The Wiper Arm and Blade The arm of a windscreen wiper is made from a long thin piece of robust metal. It is shaped to be structurally strong and narrow, so as not to obstruct a driver’s view. Arm A spring at the base of the arm, helps to keep the wiper pressed against the windscreen. Wiper blade The wiper blade consists of a metal support and a soft flexible rubber blade element. The rubber blade element wipes the windscreen surface clean. Element The rubber blade element must be periodically checked for wear damage. Blades are relatively cheap and easy to replace.

Wiper Linkage Rotating arm The wiper linkage connects the wiper motor to the wiper arms. The motor moves the linkage, which moves the wipers in the correct manner. Linkage Wiper motor Wiper arm A flexible rack type uses a pliable worm gear in conjunction with a cam to move the wiper arms. In a link type system wiper, movement is achieved through a cam and levers.

Washer System The washer system forces water onto the windscreen. This aids the wiper blade, as it clears material from the surface of the windscreen. Water (plus screen wash) is pumped from a reservoir onto the windscreen, through flexible hoses and small jets. The jets can be adjusted to vary the spray angle. Reservoir Washer pump Flexible hose Jet

Washer Pump The washer pump motor may be internally, or externally mounted. Brushes Armature From reservoir It contains an impeller that produces a centrifugal force, which pressurizes the system. Magnets Water is forced from the reservoir to the windscreen. Oil Impeller To jet A reciprocating pump was used on early vehicles. This was activated by a pedal on the floor. From reservoir To jet

Rear Washer and Wiper Some vehicles incorporate a rear washer / wiper system to provide a clear, rear, view. Reservoir Pipe The mechanical arrangement of this system is very similar to that used on the front windscreen. The washer system either shares the front reservoir with a pipe running through the roof, or it has its own separate reservoir. Wiper

Self Park Switch Schematic The self park switch is a system that ensures the wipers come to rest, at the bottom of the windscreen. The driver’s view must not be obstructed. When the wipers are switched on, the wiper motor and the drive gear rotate. The park switch is closed, except when it is opened by the cam. Drive gear When the wipers are switched off, the park switch provides voltage to the wiper motor, until it is opened by the cam. The cam stops the wipers in the correct place. Self park cam Wiper motor Park switch Wiper on/off switch Battery

Automatic Rain Sensor Some wiper systems use infrared sensors to detect refracted light, as rain falls. The signal from the sensors is sent to a control module that controls wiper speed. In adverse weather conditions, the module automatically adjusts wiper speed. A manual override switch is provided with these systems, to allow for driver control.