Electric Parking Brake Actuator Motors, Basic Function - GF42.20-P-2000A
Model All (4xWD, CAR)
Example illustration of electric parking brake actuator motor
Example illustration of electric parking brake actuator motor
Example illustration of electric parking brake actuator motor
Overview
This document contains information on:
- General
- Function
- Parking brake in applied state
- Parking brake in released state
- Brake piston fully extended
General
The left and right electric parking brake actuator motors (1) push each of the brake linings (7) against the corresponding brake disk (5) after activation of the electric parking brake (EFB). The vehicle is therefore secured against rolling away.
The left and right electric parking brake actuator motors (1) are located on the relevant brake caliper (8) toward the vehicle center.
The power is transmitted from the electric parking brake actuator motor (1) to the epicyclic gear system (12) of the spindle drive with pressure nut (2) via a toothed belt (11) to the epicyclic gear system belt pulley (10).
Function
Example illustration of parking brake in applied condition
Parking brake in applied state
After activation of the electric parking brake, the left and right electric parking brake actuator motors (1) are supplied with voltage. These drive the epicyclic gear system belt pulleys (10) in the respective epicyclic gear systems (12) via a belt drive. The spindle drive with pressure nut (2) then moves the pressure nut to the contact surface on the inside of the respective brake piston (3) and presses the brake linings (7) against the corresponding brake disk (5).
Self-locking of the spindle drive with pressure nut (2) prevents any reduction in the clamping force and therefore any reduction in the brake force after actuation of the electric parking brake actuator motors (1).
Example illustration of parking brake in released condition
Parking brake in released state
To release the electric parking brake, the electric parking brake actuator motors (1) are actuated with opposite polarity. The epicyclic gear system belt pulley (10) and the respective epicyclic gear system (12) now rotate in the opposite direction. The respective spindle drive with pressure nut (2) then pulls the pressure nut in, away from the contact surface on the inside of the brake piston (3). The required allowance is adjusted here and the brake lining wear of the brake linings (7) is taken into account.
Example illustration of brake piston fully extended
Brake piston fully extended
If the brake linings (7) or brake disks (5) on the rear axle are worn, the brake piston (3) is almost fully extended via the spindle drive with pressure nut (2). This guarantees that the contact pressure between brake linings (7) and brake disks (5) is sufficient in the locked state.
| Component descriptions | |||
| Electric parking brake actuator motor, component description | Model 223 | GF42.20-P-5004A | |
| Model 243 | GF42.20-P-5004B | ||
| Model 206 | GF42.20-P-5004C | ||
| Model 297 | GF42.20-P-5004D | ||
| Model 295 | GF42.20-P-5004E | ||
| Model 232 | GF42.20-P-5004F | ||
| Model 296 | GF42.20-P-5004G | ||
| Model 254 | GF42.20-P-5004H | ||
| Model 214 | GF42.20-P-5004K | ||
| Model 118, 177, 247 as of model year 2023 |
GF42.20-P-5004L | ||
| Model 167 as of model year 2023 |
GF42.20-P-5004M | ||
| Model 294 | GF42.20-P-5004N | ||
| Model 192 | GF42.20-P-5004R | ||
| Model 465 | GF42.20-P-5004T |