PARTS CATALOGUE

 

The Electric Parking Brake – A Success Story Since 2001

TRW Aftermarket

With the introduction of the actuator repair kit, TRW has taken the next step in workshop services. Our video provides a step-by-step guide to replacing the actuator. In recent years, more and more electronic systems, such as adaptive cruise control, lane keeping assist, lane change assist or collision warning, have been installed in vehicles. One electric system that has been used in vehicles for over 20 years is the electric parking brake (EPB). There are essentially three types of electric parking brakes: cable puller systems, systems with actuators directly on the backing plate for drum brake systems, and the parking brake with an integrated electric motor attached to the brake caliper for disc brake systems.

 

Cable puller

This system still requires handbrake cables. They are anchored in an electromechanical actuator. When the switch inside the vehicle is activated, the handbrake cables are pulled with the help of an electric motor and close the parking brake of the conventional drum or disc brake. To open the brake, the motor rotates in the opposite direction and the brake is released again.

 

Electric parking brake in drum brakes

In this system, there is one actuator on each backing plate. When the switch is activated, the actuator closes the drum brake via a short handbrake cable.

 

Caliper with integrated electric motor (actuator)

With this type of electric parking brake, an electric motor (actuator) is mounted directly on the rear axle brake caliper.

It is activated by pressing a switch in the car’s interior. A rotating spindle pushes the pressure nut against the brake piston to create the clamping force.

To open the brake, the spindle rotates in the opposite direction, the pressure nut moves back and releases the brake.

 

 

 

 

TRW EPB in volume production

The system was first installed in a Lancia Thesis in 2001, followed by the Audi A8 in 2006 and the VW Passat in 2008. Over time, a wide variety of manufacturers installed the electric parking brake in more and more vehicles, covering almost all vehicle classes.

  

Further development

The actuators have been continuously enhanced over time. While the first generation of actuators still had a single-stage swash plate gear, which was able to develop a clamping force of up to 19 kN, subsequent generations came with a double-stage planetary gear.

It enables a clamping force of up to 25 kN which means that it can also be used in larger and heavier vehicles. The further development of the EPB will lead to even more compact and powerful actuators in the future.

  

Maintenance in the workshop

If the brake pads and/or brake discs need to be changed on an EPB with an integrated actuator, the system must be put into maintenance mode beforehand with the help of a diagnostic device. In doing so, the pressure nut is retracted to the end stop. In contrast to mechanical parking brake systems, the pads can now be changed by pushing back the brake piston. After repair, the system must be reactivated and recalibrated with a tester.

Until now, whenever electric parking brake diagnostics detected an electrical or mechanical fault in the actuator, the entire brake caliper had to be replaced. The need for bleeding, the more expensive spare parts and the time involved would result in higher repair costs. That's why ZF Aftermarket is now offering the new EPB Actuator Repair Kit as an inexpensive and resource-saving alternative to a complete replacement. The kit includes an electric actuator, mounting screws and an O-ring. From now on, the EPB can be repaired quickly and inexpensively for the customer.

Electric front-axle parking brake

ZF is currently launching the volume production of the industry's first electric parking brake (EPB) for the front axle. With this solution, automotive manufacturers can now also equip smaller vehicles with an advanced EPB system and design their interior without the standard parking brake lever. The start of volume production for the front axle EPB is currently taking place in Korea and China.

In addition to the common parking brake function, the EPB with the auto-hold function makes hill starts easier. Thanks to the stop-and-go function, the braking system makes your ride much more comfortable in city traffic or in traffic jams. In addition, the higher static load distribution on the front axle increases safety when parking the vehicle on slippery slopes.

The EPB on the front axle eliminates the need for manual parking brake components on the drum or disc brakes on the rear axle and requires only minor adjustments to the front brake calipers. Another advantage is that all the necessary electronic components and software applications can be integrated into the existing ESC control unit. In addition, the weight of the manual parking brake on the rear axle is eliminated.

 

With the introduction of the actuator repair kit, TRW has taken the next step in workshop services. Our video provides a step-by-step guide to replacing the actuator. In recent years, more and more electronic systems, such as adaptive cruise control, lane keeping assist, lane change assist or collision warning, have been installed in vehicles. One electric system that has been used in vehicles for over 20 years is the electric parking brake (EPB). There are essentially three types of electric parking brakes: cable puller systems, systems with actuators directly on the backing plate for drum brake systems, and the parking brake with an integrated electric motor attached to the brake caliper for disc brake systems.

 

Cable puller

This system still requires handbrake cables. They are anchored in an electromechanical actuator. When the switch inside the vehicle is activated, the handbrake cables are pulled with the help of an electric motor and close the parking brake of the conventional drum or disc brake. To open the brake, the motor rotates in the opposite direction and the brake is released again.

 

Electric parking brake in drum brakes

In this system, there is one actuator on each backing plate. When the switch is activated, the actuator closes the drum brake via a short handbrake cable.

 

Caliper with integrated electric motor (actuator)

With this type of electric parking brake, an electric motor (actuator) is mounted directly on the rear axle brake caliper.

It is activated by pressing a switch in the car’s interior. A rotating spindle pushes the pressure nut against the brake piston to create the clamping force.

To open the brake, the spindle rotates in the opposite direction, the pressure nut moves back and releases the brake.

 

 

 

 

TRW EPB in volume production

The system was first installed in a Lancia Thesis in 2001, followed by the Audi A8 in 2006 and the VW Passat in 2008. Over time, a wide variety of manufacturers installed the electric parking brake in more and more vehicles, covering almost all vehicle classes.

  

Further development

The actuators have been continuously enhanced over time. While the first generation of actuators still had a single-stage swash plate gear, which was able to develop a clamping force of up to 19 kN, subsequent generations came with a double-stage planetary gear.

It enables a clamping force of up to 25 kN which means that it can also be used in larger and heavier vehicles. The further development of the EPB will lead to even more compact and powerful actuators in the future.

  

Maintenance in the workshop

If the brake pads and/or brake discs need to be changed on an EPB with an integrated actuator, the system must be put into maintenance mode beforehand with the help of a diagnostic device. In doing so, the pressure nut is retracted to the end stop. In contrast to mechanical parking brake systems, the pads can now be changed by pushing back the brake piston. After repair, the system must be reactivated and recalibrated with a tester.

Until now, whenever electric parking brake diagnostics detected an electrical or mechanical fault in the actuator, the entire brake caliper had to be replaced. The need for bleeding, the more expensive spare parts and the time involved would result in higher repair costs. That's why ZF Aftermarket is now offering the new EPB Actuator Repair Kit as an inexpensive and resource-saving alternative to a complete replacement. The kit includes an electric actuator, mounting screws and an O-ring. From now on, the EPB can be repaired quickly and inexpensively for the customer.

Electric front-axle parking brake

ZF is currently launching the volume production of the industry's first electric parking brake (EPB) for the front axle. With this solution, automotive manufacturers can now also equip smaller vehicles with an advanced EPB system and design their interior without the standard parking brake lever. The start of volume production for the front axle EPB is currently taking place in Korea and China.

In addition to the common parking brake function, the EPB with the auto-hold function makes hill starts easier. Thanks to the stop-and-go function, the braking system makes your ride much more comfortable in city traffic or in traffic jams. In addition, the higher static load distribution on the front axle increases safety when parking the vehicle on slippery slopes.

The EPB on the front axle eliminates the need for manual parking brake components on the drum or disc brakes on the rear axle and requires only minor adjustments to the front brake calipers. Another advantage is that all the necessary electronic components and software applications can be integrated into the existing ESC control unit. In addition, the weight of the manual parking brake on the rear axle is eliminated.