US Patent 9706290 Balanced armature based valve

A balanced armature (“BA”) based valve is described. The valve includes a motor having a coil assembly and a magnetic system, an armature extending through or being located adjacent to the motor, a drive pin coupled to the armature, and a valve flap of a membrane having a hole therein. The valve flap is actuated by the drive pin into open and closed positions, in response to respective motions of the armature. A housing contains the motor, the armature, the drive pin, and the membrane. In one embodiment, the membrane is attached to the housing and divides the housing into an upper space and a lower space, and there is airflow through the hole, between the upper space and the lower space, only when the valve flap is open. A first spout of the housing may deliver sound generated by an acoustic driver in the housing into a wearer's ear canal, and is also open to the upper space. A second spout of the housing is open to the bottom space and to an ambient environment. Other embodiments are also described.