SMA valve for controlling pressurized air supply to an air cell in a vehicle seat
First Claim
1. An SMA valve for controlling pressurized air supply to an air cell in a vehicle seat comprising:
- a valve housing,a valve element moveably suspended with respect to a mounting plate in the housing and moveable between a closed position in which the valve element is in sealing abutment with a valve seat establishing a closed state of the valve, and an open position in which the valve element is moved away from the valve seat corresponding to an open state of the valve,a spring element adapted to exert a bias force on the valve element urging the valve element to the closed position,an SMA wire extending between a point fixed in the housing and the valve element, and arranged such that shortening of the SMA wire upon exceeding a threshold temperature exerts a force on the valve element which pulls the valve element away from the closed position to the open position against the bias force of the spring element,a conductor arranged with respect to the mounting plate such that the conductor is moved into contact with contact area on the mounting plate to close an electrical circuit as a result of the valve element reaching the open position, and the conductor is moved away from the contact area when the valve element leaves the open position,a control unit arranged to supply 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 a suspension of the valve element is arranged such that the valve element moves relative to the mounting plate between the closed and open positions, and wherein an actuator arm is fixed to and extends from the suspension and is arranged such that, upon movement of the valve element from the closed to the open position, the actuator arm moves towards the mounting plate to bring at least a portion of the conductor into contact with the contact area on the mounting plate.
2 Assignments
0 Petitions
Accused Products
Abstract
SMA valve for controlling pressurized air supply to an air cell in a vehicle seat comprising: a valve housing; a valve element (4) 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 (1) extending between a fixed point and the valve element (4), and which is arranged such that shortening of the SMA wire upon exceeding its threshold temperature exerts a force on the valve element (4) pulling it from the closed to the open position; a conductor (20) 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 (8, 10, 10′, 12, 12′, 14, 14′) of the valve element is arranged such that the valve element moves parallel to the mounting plate (30) between the closed and open positions; and an actuator arm (16) 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 (20) into contact with a contact area (34) on the mounting plate.
73 Citations
16 Claims
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1. An SMA valve for controlling pressurized air supply to an air cell in a vehicle seat comprising:
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a valve housing, a valve element moveably suspended with respect to a mounting plate in the housing and moveable between a closed position in which the valve element is in sealing abutment with a valve seat establishing a closed state of the valve, and an open position in which the valve element is moved away from the valve seat corresponding to an open state of the valve, a spring element adapted to exert a bias force on the valve element urging the valve element to the closed position, an SMA wire extending between a point fixed in the housing and the valve element, and arranged such that shortening of the SMA wire upon exceeding a threshold temperature exerts a force on the valve element which pulls the valve element away from the closed position to the open position against the bias force of the spring element, a conductor arranged with respect to the mounting plate such that the conductor is moved into contact with contact area on the mounting plate to close an electrical circuit as a result of the valve element reaching the open position, and the conductor is moved away from the contact area when the valve element leaves the open position, a control unit arranged to supply 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 a suspension of the valve element is arranged such that the valve element moves relative to the mounting plate between the closed and open positions, and wherein an actuator arm is fixed to and extends from the suspension and is arranged such that, upon movement of the valve element from the closed to the open position, the actuator arm moves towards the mounting plate to bring at least a portion of the conductor into contact with the contact area on the mounting plate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification