Active anti-roll bars

The active anti-roll bars are vertically split in the middle. The active anti-roll bar consists of a swivel motor and, attached to it, the two halves of the anti-roll bar with press-fitted roller bearing mountings. The swivel motor shaft and housing are each attached to one half of the anti-roll bar. In the swivel motor, the opposing chambers are linked. This means the chambers each have the same pressure. Two chambers are supplied with high pressure via one connection. The two other chambers are connected to the return line to the expansion tank. Variation of the pressure varies the force generated by the motor. That force produces torque which rotates the shaft relative to the housing. As one half of the anti-roll bar is attached to the shaft and the other to the housing, the two halves of the anti-roll bar then twist in opposite directions to one another. The momentum that this creates counteracts/stabilizes the rolling motion. The maximum system pressure is 180 bar.

Fig 1: Identifying Pressure Relief Valve With Air Filter Flap

Courtesy of BMW OF NORTH AMERICA, INC.