Mechanical Brake Assistance (EBA)
- Snap-ring
- Rubber disc
- Control housing
- Ratio disc
- Spring, Ball socket
- Valve piston
- Connecting device.
- Bearing race
- Guide sleeve
- Seal
- Ball socket
- Ball bearing
- Locking sleeve
- Spring, Locking sleeve
- Clock valve
- Mounting bracket
- Retainer
- Spring, Clock valve
- Gasket
- Push rod spring
- Spring
Mechanical brake assistance (EBA) is integrated with the servo cylinder. The regular function of the servo cylinder is not affected, although the design in the guide housing is affected slightly.
Partial braking position without mechanical brake assistance (EBA)
If the movement from the speed and force of the brake pedal does not exceed the designed locking movement, the locking sleeve (13) cannot go to its final position. The vehicle brakes without brake assistance.
The ball socket (11) can move axially throughout the entire movement of the valve piston (6) due to the ball bearings (12), which are free to move radially over the ramp on the ball socket.
Activation of the EBA function
When the switching movement is exceeded (sufficiently high speed and force from the brake pedal are required), the movement of the valve piston (6) moves the ball bearings (12) radially inwards over the ball socket (11) ramp. The locking sleeve (13), which is pressed by the spring (14), can therefore move to the right (in the illustration). The ball bearings are now locked and the EBA function is activated.
Full braking position without physical effect (EBA function activated)
When the EBA function is activated (the ball bearings locked and the connecting device in activated position), the reaction disc (2) force is transferred to the bearing race (8) and the guide housing (3) via the ball socket (11) and the ball bearings (12). The driver can now increase the brake pressure to fully depressed brake pedal (full pedal deflection) with no physical effort.
Release position mechanical brake assistance (EBA)
To reduce the brake pressure, the connecting device remains in activated position. The driver controls the reduction of the pressure via the pedal movement. In the same way as with a servo cylinder without brake assistance, this is achieved by closing the valve for atmospheric pressure and simultaneously opening the vacuum valve. Immediately before the resting position is achieved, the locking sleeve (13) comes into contact with the mounting bracket (16). The locking sleeve is then pressed back (to the left in the illustration) to its original position. The ball bearings are released and the connecting device is in passive mode once more. The EBA function is no longer activated. The locking sleeve (13) returns to its original position and the brake assistance function is terminated.