Why do cars have hand brakes

Electric parking brake - handbrake

The electric parking brake is increasingly replacing the mechanical handbrake and is operated via a switch in the vehicle interior. It is used to secure the parked vehicle against rolling away.

function

The brake calipers of the electric parking brake (often abbreviated to "EPB") are provided with a drive unit made up of an electric motor and gear, the so-called actuator. This is operated via a switch and closes the brake by moving the brake piston in the brake calliper so that the brake pads are pressed against the brake disc. This means that the vehicle can also be parked safely on sloping roads. The electric parking brake is a combination of a hydraulic foot brake and an electrically operated parking brake.

By integrating it into the vehicle electronics, the functional scope of the electric parking brake has been significantly expanded compared to the mechanical handbrake.

Here are some examples:

Parental controls
The electric parking brake cannot be opened accidentally when the ignition is switched off.

Automatic tensioning
When the vehicle is stationary, the parking brake is automatically applied as soon as the driver's door is opened or the driver loosens the seat belt.

Automatic opening
With this additional function, the parking brake is released as soon as the driver disengages the clutch while a gear is engaged or, in the case of a vehicle with an automatic transmission, takes his foot off the brake.

 

security

Thanks to the high and, above all, constant clamping forces of the electric parking brake, the vehicle can be parked safely even on extreme slopes. That alone is an important safety aspect. The real strengths of this system can be seen even more clearly in the dynamic safety functions:

Emergency braking function
The value of the minimum deceleration of a parking brake prescribed by law can only be applied by a mechanical brake with great effort on the part of the driver. In addition, a mechanical system must be in perfect technical condition for this. This is often not guaranteed in older vehicles. Here, too, the electric parking brake offers a decisive plus in terms of safety. If the electric parking brake is applied while driving, the EPB control unit interprets this as emergency braking. In order to prevent the vehicle from breaking out due to a blocking rear axle, the parking brake is closed and reopened at intervals - similar to the function of an anti-lock braking system. This mode safely brakes the vehicle to a standstill.

Traction help
When starting from a hillside (starting on a hill), the parking brake automatically opens as soon as the engine has enough torque available to start the vehicle safely. Should the vehicle accidentally stall and roll back, this will be recognized by the EPB system and the parking brake will be applied immediately.

environmental Protection

The wear and tear of the transmission devices of a mechanical handbrake (handbrake cables, pulleys, levers, etc.) can lead to the friction materials of brake linings or brake shoes being in permanent contact with the disc or brake drum. This leads to increased pollution of the environment by brake dust. In addition, all components have to be replaced and disposed of from time to time. By eliminating these components in an electrical system, the electric parking brake helps protect the environment.

Value retention

Frozen, stiff or even torn handbrake cables and the associated repairs are finally a thing of the past with the electric parking brake. Electric parking brakes are less prone to failure and almost maintenance-free. More and more vehicles, including those in the medium price segment, are now equipped with electric parking brakes. The electric parking brake plays an important role as a sought-after safety feature - even if it is to be resold.