Bosch makes aluminum brake booster lighter

September 12, 2013: The lighter the vehicle, the less fuel it consumes and the more dynamically it can be driven. In their quest to reduce vehicle weight, automakers and their suppliers are increasingly replacing conventional steel with lighter metals. Bosch has developed the Tie Rod 4 vacuum brake booster, which the technology supplier now offers in various aluminum models. “The new aluminum versions of our brake booster are only half as heavy as conventional steel ones,” says Gerhard Steiger, the president of the Bosch Chassis Control Systems division. “Depending on the size, this means a weight saving of up to 1.5 kilos compared to earlier models.” The weight-reduced versions of the Bosch brake booster will feature in three production-vehicle models later this year. When Bosch engineers introduced the steel Tie Rod 4 in 2011, they had already succeeded in significantly reducing its weight compared to previous models. The new aluminum brake booster is now even lighter. It is available as a single model with a 10-inch or 11-inch diameter or as a tandem version with a diameter of 8+8 or 8+9 inches. Although the thickness of the walls has been reduced in the aluminum models, rigidity is ensured by the integrated tension rods. This rigidity is essential for a good pedal feel as well to keep pedal play to a minimum.

A ‘through-bolt’ version is also available, which means that any mounting work can be done exclusively from the engine compartment. As with all Bosch brake boosters, the system is complemented perfectly by the Bosch TMC 8e brake master cylinder. This is 20 percent lighter and 30 percent shorter than its predecessor.

All versions of the Tie Rod 4 can be manufactured worldwide, which means the supplier is able to offer automakers standardised solutions, especially for global vehicle platforms.

Photograph: Bosch is now offering aluminium variants of its Tie Rod 4 brake boosters. Depending on size, this means a weight saving of as much as 1.5 kilos compared with previous models.