Spring from ContiTech simulates braking sensation
Comfort improvement for hybrid vehicles with electronic brake systems: a special rubber spring from ContiTech restores the sensation of braking to the pedal in electronic brake systems / Ford USA uses it in series production
Brake servo units work with underpressure that is also supplied by combustion engines. In hybrid vehicles on the contrary, a vacuum pump generates the underpressure - either because there is no longer a combustion engine or because it functions as a charging station for electric engines. If that is the case, it would always run at low speed and therefore produce too little underpressure. The brake pedals in hybrid vehicles have a triggering function only: braking resistance no longer builds up in the pedal.
ContiTech has developed the rubber spring used in a braking simulator to provide drivers with the resistance they are used to - and Ford USA is using this braking simulator in series production. The molded part shaped like a pyramid is slightly larger than a box of matches. The rubber spring is part of a small box with a circular opening that receives a shaft extending from the pedal at a right angle. A connecting rod that diverts the lever action of the brake pedal to the interior of the box is located on the shaft. The working chamber of the connecting rod is restricted by the rubber spring.
When the brake pedal is pressed, the end of the connecting rod moves toward the rubber spring and compresses it. That creates a braking sensation in the pedal foot. "Depending on the rubber spring's degree of hardness and the shape of its roof, we can simulate different types of braking effect: from sporty to comfortable," explained Möllering.
The rubber springs can have different roof shapes and, depending on the material mix, they respond to the mechanical pressure sharply or gradually. "We are able to provide vehicle manufacturers with rubber springs that are configured according to customer specifications," said Möllering. "In the braking simulator, the braking resistance of individual vehicle types can be simulated."
In addition, a special pedal stop developed by ContiTech cushions the rebound of the brake pedal when the braking procedure is completed. The molded part is also inside the box, opposite the rubber spring on the other side of the connecting rod. "The pedal stop is another area of comfort improvement," he said. "It prevents clicking noises that may interfere with the driving experience."
ContiTech Antriebssysteme GmbH
ContiTech AG, Hanover, is the world's no. 1 specialist for rubber and plastics technology in the non-tire rubber sector. The company develops and produces functional parts, components and systems for the automotive industry and other important industries. The company has a workforce of around 21,000 employees. In 2008 it realized sales of about €3 billion. ContiTech is a division of Continental AG. With sales exceeding €24 billion in 2008, the Continental Corporation is one of the top automotive suppliers worldwide. As a supplier of brake systems, systems and components for the powertrain and chassis, instrumentation, infotainment solutions, vehicle electronics, tires and technical elastomers, the corporation contributes towards enhanced driving safety and protection of the global climate. Continental is also a competent partner in networked automobile communication. The corporation currently employs approximately 130,000 at nearly 190 locations in 35 countries.