Drive reversible electromotive automatic reel

The drive of the reversible electromotive automatic reel primarily consists of the following parts:

• Electric motor
• Control unit
• Gear with clutch (the clutch sets up the connection to the reel mechanism)
• Automatic reel (mechanical function)

The voltage supply of the electric motor occurs via Terminal 30. The ground connection occurs via Terminal 31. The electric motor is supplied with current (direction of motor rotation "tension seat belt") and moves an output wheel in the clutch by means of a gear. In the clutch, locking pawls move out and enter the clutch case. The clutch case is firmly connected to the drive shaft of the reel mechanism. This rolls up the seat belt. To open the clutch, the direction of rotation of the electric motor must be briefly changed (opposite motor direction of rotation "tension belt"). If the connection between the electric motor and reel mechanism is interrupted, the reel mechanism works in the same way as a conventional mechanical reel mechanism. There are two hall effect sensors on the circuit board which detect the rotational movement of a magnetic disc. The magnetic disc is integrated into the housing of the control unit and is driven by the coil of the automatic reel. This monitors the pullout of the seat belt. The direction of rotation of the electric motor can be changed through a corresponding activation via the control unit.

The following graphic shows the design of the reversible electromotive automatic reel.

Fig 1: Identifying Motor Housing With Electric Motor And Case Cover

Courtesy of BMW OF NORTH AMERICA, INC.