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

• US 9,945,490 B2
• Filed: 12/13/2013
• Issued: 04/17/2018
• Est. Priority Date: 12/13/2013
• Status: Active Grant

• Current Assignee: Lear Corporation
• Original Assignee: Kongsberg Automotive Ab (Kongsberg Automotive ASA)
• Inventors: Dankbaar, Frank, Grnhage, Anders
• Primary Examiner(s): Venkatesan, Umashankar
• Application Number:
  US15/104,081
• Publication Number:
  US 20160363230A1
• Time in Patent Office: 1,586 Days
• Field of Search: 251 11, 25112904, 25112906
• CPC Class Codes: A61H 23/004 With mechanical drive, e.g. spring mechanism or vibrating unit being hit for starting vibration and then applied to the body of a patient
• CPC Class Codes: B60N 2/0244 with logic circuits
• CPC Class Codes: B60N 2/914 Hydro-pneumatic adjustments of the shape
• CPC Class Codes: B60N 2/976 massaging systems
• CPC Class Codes: F03G 7/065 using a shape memory element
• CPC Class Codes: F16K 31/002 actuated by temperature variation thermo-electric F16K31/025
• CPC Class Codes: F16K 31/025 actuated by thermo-electric means
• CPC Class Codes: G05D 7/0635 by action on throttling means G05D7/0688, G05D7/0694 take precedence

Abstract

SMA valve for controlling pressurized air supply to an air cell in comprising: a valve housing; a valve element (4) which is moveably suspended with respect to a mounting plate (30) in the housing between a closed position and an open position of the valve; a spring element adapted to exert a bias force on the valve element (4) to the closed position; a SMA wire (1) arranged such that shortening of the SMA wire upon exceeding its threshold temperature pulls the valve element to the closed position; a conductor (20) arranged on the valve element (4) in contact with the SMA wire (1) and arranged such that it comes into contact with a conducting surface (34) on the mounting plate (30) to close an electrical circuit when the valve element reaches its open position; a control unit arranged to supply electrical power to the SMA wire 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, characterized in that the suspension (8, 10, 10′, 12, 12′, 14, 14′) of the valve element (4) is arranged such that the valve element moves parallel to the mounting plate (30) between the closed and open positions, and the conductor (20) is arranged to extend along a first portion (22) parallel to the longitudinal and moving direction of the valve element (4) and along a second portion (24) towards the mounting plate (30) and into a slot (32) formed therein, the conducting surface (34) being located in the slot such that an exposed end of the conductor (20) comes into contact with the conducting surface (34) in the slot (32) when the valve element (4) reaches its open position.

Claims

1. A SMA valve for controlling pressurized air supply to an air cell in a vehicle seat comprising:

a valve housing,

a valve element which is moveably suspended with respect to a mounting plate in the housing between a closed position in which it 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 it to the closed position,

a SMA wire extending between the mounting plate 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 against the bias force of the spring element,

a conductor arranged on the valve element in contact with the SMA wire and arranged such that it comes into contact with a conducting surface on the mounting plate to close an electrical circuit when the valve element reaches the open position, and

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 the conductor is arranged to extend along a first portion and along a second portion towards the mounting plate and into a slot formed therein, the conducting surface being located in the slot such that an exposed end of the conductor comes into contact with the conducting surface in the slot when the valve element reaches the open position.

2. The SMA valve according to claim 1, 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 wherein the conductor is arranged to extend along a first portion parallel to the longitudinal and moving direction of the valve element and along a second portion towards the mounting plate and into the slot formed therein.

3. The SMA valve according to claim 1, wherein the valve element is suspended above the mounting plate which comprises a mounting body connected to the mounting plate, two connecting links extending between the mounting body and the valve element at a distance from each other in moving direction of the valve element, the first connecting link being connected to the mounting body by a first hinge and to the valve element by a first valve element hinge, the second connecting link being connected to the mounting body by a second hinge and to the valve element by a second valve element hinge, wherein the connecting links are arranged such that they pivot over an angular range with respect to the longitudinal direction of the valve element and the moving direction of the valve element when the valve element moves between the closed and open positions, said angular range including an 90°

angle between the connecting links and said longitudinal and moving direction.

4. The SMA valve according to claim 3 wherein the mounting body, the first connecting link, the second connecting link, the valve element and the hinges are integrally formed of plastic material and that the first and second hinges as well as the first and second valve element hinges are solid state hinges each having a zone of weakened material thickness.

5. The SMA valve according to claim 4, wherein the conductor is an elongated metal element which is moulded into the valve element with two exposed areas of the conductor, the first exposed area being in a groove which is formed around the valve element on a side facing away from the mounting plate, the SMA wire extending through said groove, and the second exposed area being formed by an end portion of the metal element deflected towards the mounting plate and extending into the slot therein.

6. The SMA valve according to claim 5, wherein the valve element is provided with an angled lateral extension extending towards the mounting plate and enclosing the conductor along part of the second portion.

7. The SMA valve according to claim 6, wherein the SMA wire extends from a first fixation point where it is fixed with respect to the mounting plate along said second portion to the deflection member, along said first portion to the valve element where it is guided in the groove around the valve element to an opposite side where the SMA wire is extending in a symmetrical manner along an opposite first portion to an opposite deflection member and from there along an opposite second portion to an opposite fixation point where fixed with respect to the mounting plate.

8. The SMA valve according to claim 5, wherein the SMA wire extends from a first fixation point where it is fixed with respect to the mounting plate along said second portion to the deflection members, along said first portion to the valve element where it is guided in the groove around the valve element to an opposite side where the SMA wire is extending in a symmetrical manner along an opposite first portion to an opposite deflection member and from there along an opposite second portion to an opposite fixation point where fixed with respect to the mounting plate.

9. The SMA valve according to claim 4, the SMA wire extends along the valve element in a first rectilinear portion to a deflection member at an angle with respect to the longitudinal and movement direction of the valve element when moving from the closed to the open position, which angle is smaller than 90°

, and from the deflection member in a second portion at an angle with respect to the longitudinal and movement direction of the valve element that is smaller than 45°

.

10. The SMA valve according to claim 3, the SMA wire extends along the valve element in a first rectilinear portion to a deflection member at an angle with respect to the longitudinal and movement direction of the valve element when moving from the closed to the open position, which angle is smaller than 90°

, and from the deflection member in a second portion at an angle with respect to the longitudinal and movement direction of the valve element that is smaller than 45°

.

11. The SMA valve according to claim 1, wherein the SMA wire extends along the valve element in a first rectilinear portion to a deflection member at an angle with respect to the longitudinal and movement direction of the valve element when moving from the closed to the open position, which angle is smaller than 90°

, and from the deflection member in a second portion at an angle with respect to the longitudinal and movement direction of the valve element that is smaller than 45°

.

12. The SMA valve according to claim 11, wherein the deflection member are provided by a protrusion on the mounting body around which the SMA wire is routed in a groove.

13. The SMA valve according to claim 12, wherein the SMA wire extends in the second portion parallel to the longitudinal and movement direction of the valve element.

14. The SMA valve according to claim 12, wherein the conductor is an elongated metal element which is moulded into the valve element with two exposed areas of the conductor, the first exposed area being in a groove which is formed around the valve element on a side facing away from the mounting plate, the SMA wire extending through said groove, and the second exposed area being formed by an end portion of the metal element deflected towards the mounting plate and extending into the slot therein.

15. The SMA valve according to claim 11, wherein the SMA wire extends in the second portion parallel to the longitudinal and movement direction of the valve element.

16. The SMA valve according to claim 15, wherein the conductor is an elongated metal element which is moulded into the valve element with two exposed areas of the conductor, the first exposed area being in a groove which is formed around the valve element on a side facing away from the mounting plate, the SMA wire extending through said groove, and the second exposed area being formed by an end portion of the metal element deflected towards the mounting plate and extending into the slot therein.

17. The SMA valve according to claim 11, wherein the conductor is an elongated metal element which is moulded into the valve element with two exposed areas of the conductor, the first exposed area being in a groove which is formed around the valve element on a side facing away from the mounting plate, the SMA wire extending through said groove, and the second exposed area being formed by an end portion of the metal element deflected towards the mounting plate and extending into the slot therein.