28.03.2025

Brake housings for autonomous driving

MAPAL's solution is a technically sophisticated combination

#Products #Industries #Technology #Automotive #Reaming&FineBoring #Milling

Combined brake housing unites main brake cylinder, brake booster and ABS/ESP in a single part. This component smooths the way for self-driving cars and saves weight. When it comes to machining complex aluminium workpieces, MAPAL’s solution expertise is very much in demand. 

While self-driving cars are already permitted in various countries, the legal framework for them is still not in place in Europe, where only partial driving automation is permitted. The combined break housing – which unites the main brake cylinder, the brake booster and ABS/ESP in a single part – supports all levels of automated driving. Brake-by-wire is closely related to this, whereby the brake signal is no longer sent hydraulically but rather electrically. 

A requirement for autonomous driving

While the combined brake housing is a prerequisite for automated driving, it also has further advantages. Because they are applied electronically, the brakes can be operated more quickly, which results in considerably shorter braking distances in an emergency. 
MAPAL offers appropriate solutions and suitable tools for the development of combined brake housings.
MAPAL's solution expertise is in demand for the machining of combined brake housings made of aluminum.  ©MAPAL
While the first automotive suppliers have already presented all-electric braking systems, vehicles only use a precursor today – the so-called wet-dry system. This hybrid form uses a hydraulic brake at the front and an all-electric system at the rear axle. This redundancy is made possible by a sophisticated central component that combines both worlds in the tiniest of spaces. 

Defined chip breaking for short aluminium chips

Aluminium with a low silicon content of less than 1% is the material of choice for the combined brake housing. To save costs, extruded profiles are used for the most part. Long chips are created during machining due to the grain flow and the low silicon content. To ensure excellent chip breaking when boring and reaming aluminium with low silicon content using PCD blades, MAPAL makes use of application-specific chip-breaking geometries. Their special topology, which was developed with the help of 3D simulations, ensures defined chip breaking and thus short chips, even at low feed rates and machining allowances. This enables maximum performance and process reliability. 

High demands on surface finishes

With its many bores, the part then looks like Swiss cheese. Each bore has tight tolerance requirements, calling for precision in the IT6 to IT7 range. Because liquid flows through the combined housing, there are high demands on the surface finish. The surface must be free of scoring which can be formed by chips or vibration during machining. Some bores are subsequently anodised to provide more resistance to wear. Rawness of Rz 1 is required to hold this coating. 
The picture shows the chip breakage during machining in detail.
Application-specific chip breaker geometries from MAPAL ensure excellent chip breaking when boring and reaming low-silicon aluminum with PCD cutting edges.  ©MAPAL
Für die Bearbeitung der kombinierten Bremsgehäuse stellt MAPAL angepasste Werkzeuge bereit. Dazu gehören spezielle Hartmetallstufenbohrer für die Vorbearbeitung der Motorbohrung. Im Nachgang kommen meist PKD-Werkzeuge mit vielen Schneiden zum Einsatz, um die gewünschte Oberflächenqualität zu erzeugen. Die unterschiedlichen Konturen der Ventilbohrungen stellen Zirkularfräser mit sehr hoher Konturgenauigkeit her.  

Produktive Bohrungslösungen wirken sich kostensparend aus

In den Aluminiumblock werden zudem diverse Tiefbohrungen eingebracht, die im Bauteil ineinandergreifen. Spiralisierte Werkzeuge mit Bearbeitungstiefen bis zu 30xD sorgen für prozesssichere Späneabfuhr, damit das Medium später ungehindert fließen kann. 20 Prozent der Taktzeit von insgesamt etwa 15 Minuten entfallen allein auf die Tiefbohrungen, so dass produktive Bohrungsbearbeitungslösungen einen starken Effekt auf die Kosteneinsparungen haben. 

Die Stückzahlen der kombinierten Bremsgehäuse erreichen pro Jahr bis zu fünf Millionen Bauteile. Sie werden meist auf mehrspindligen Maschinen in zwei Aufspannungen gefertigt, wobei Vier-Spindler mit ihrer hohen Produktivität bevorzugt werden. Als Technologiepartner erarbeitet MAPAL mit seinen Kunden anwendungsorientierte Bearbeitungsprozesse und Werkzeugpakete für dieses Aluminiumbauteil. 

Portrait MAPAL Redakteur Ostertag Mathias

Kontakt

Mathias Ostertag Public Relations mathias.ostertag@mapal.com Tel.: +49 7361 585 3566

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