Sma valve for controlling pressurized air supply to an air cell in a vehicle seat

Abstract

SMA valve for controlling pressurized air supply to an air cell in a vehicle seat comprising: a valve housing; a valve element () moveable between a closed position in which it is in sealing abutment with a valve seat, and an open position; a spring element urging the valve element to the closed position; a SMA wire () extending between a fixed point and the valve element (), and which is arranged such that shortening of the SMA wire upon exceeding its threshold temperature exerts a force on the valve element () pulling it from the closed to the open position; a conductor () arranged to close an electrical circuit when the valve element reaches its open position; a control unit for supplying electrical power to the SMA wire for opening the valve and to detect closure of the electrical circuit, and arranged to reduce the electrical power supply to the SMA wire when detecting closure of the electrical circuit, wherein the suspension () of the valve element is arranged such that the valve element moves parallel to the mounting plate () between the closed and open positions; and an actuator arm () fixed to and extending from the suspension is arranged such that it, upon movement of the valve element to the open position, pivots towards the mounting plate bringing the conductor () into contact with a contact area () on the mounting plate.