Drive unit for a micro valve comprising a shape memory alloy, and micro valve

Patent metadata

Field	Value
Publication number	US-9267617-B2
Application number	US-201113190577-A
Country	US
Kind code	B2
Filing date	Jul 26, 2011
Priority date	Jul 28, 2010
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

A drive unit for a micro valve comprises a housing, a spring and at least one shape memory alloy element which is attached to the housing in a deflectable manner. The shape memory alloy element is loaded by the spring towards a deflected position and is movable in response to a temperature increase and the shape memory effect activated thereby, into a position which is at least less deflected against an increasing load by the spring. A normally closed micro valve includes a fluid housing, at least one valve seat, a sealing element opposite the valve seat, and a drive unit of the type mentioned above. The shape memory alloy element cooperates with the sealing element and exerts an operating force on the sealing element for closing and opening the valve seat with or against a compression spring force.

First claim

What is claimed is:

1. A drive unit for a micro valve comprising:
a housing free from fluid ports;
a spring;
at least one shape memory alloy element which is attached to the housing in a deflectable manner, is loaded by the spring towards a deflected position, and is movable in response to a temperature increase, and the shape memory effect activated thereby, into a position which is at least less deflected against an increasing load by the spring;
wherein the at least one shape memory alloy element comprises at least one pair of foils stacked upon each other which are connected to each other at an outer perimeter at least in sections and are biased by the spring into the deflected position, and wherein the foils include a central passage through which the spring extends; and
wherein the at least one shape memory alloy element and the spring engage the same side of a transmission element, and wherein the transmission element is formed as one-piece.

2. The drive unit according to claim 1 , in which the spring is a compression spring resting against a support on the housing and engaging the transmission element.

3. The drive unit according to claim 1 , in which at least two pairs of foils are stacked upon each other and neighboring foils of the two pairs are connected to each other on a circumference of the central passage for the spring.

4. The drive unit according to claim 1 , wherein the shape memory alloy element is firmly connected to the transmission element.

5. The drive unit according to claim 1 , wherein the foils have an elliptical, circular or triangular shape.

6. The drive unit according to claim 1 , wherein the foils can be heated by an electric current flowing in a foil interior.

7. The drive unit according to claim 1 , wherein the foils can be cooled by an active or passive cooling element.

8. The drive unit according to claim 1 , wherein the at least one shape memory alloy element is concentric with the spring, and wherein the at least one shape memory alloy element is positioned radially outwardly of the spring.

9. A drive unit for a micro valve comprising:
a housing;
a spring;
at least one shape memory alloy element which is attached to the housing in a deflectable manner, is loaded by the spring towards a deflected position, and is movable in response to a temperature increase, and the shape memory effect activated thereby, into a position which is at least less deflected against an increasing load by the spring;
wherein the at least one shape memory alloy element comprises at least one pair of foils stacked upon each other which are connected to each other at an outer perimeter at least in sections and are biased by the spring into the deflected position, and wherein the foils include a central passage through which the spring extends;
wherein the at least one shape memory alloy element and the spring engage the same side of a transmission element, and wherein the transmission element is formed as one-piece; and
wherein the spring is a compression spring resting against a support on the housing and engaging the foil which is farthest from the support.

10. A micro valve that is a normally closed micro valve, comprising:
a fluid housing;
at least one valve seat;
a sealing element directly interacting with the at least one valve seat to seal fluid within the fluid housing;
a drive unit comprising
a drive unit housing separated from the fluid housing by the sealing element which prevents fluid from entering the drive unit housing, wherein the drive unit housing is free from fluid ports,
a spring,
at least one shape memory alloy element which is attached to the drive unit housing in a deflectable manner, is loaded by the spring towards a deflected position, and is movable in response to a temperature increase, and the shape memory effect activated thereby, into a position which is at least less deflected against an increasing load by the spring,
wherein the at least one shape memory alloy element comprises at least one pair of foils stacked upon each other which are connected to each other at an outer perimeter at least in sections and are biased by the spring into the deflected position. and wherein the foils include a central passage through which the spring extends, and
wherein the at least one shape memory alloy element and the spring engage the same side of a transmission element and wherein the transmission element is formed as one-piece.

11. The micro valve according to claim 10 , wherein the sealing element comprises a membrane arranged directly between the valve seat and the transmission element to prevent fluid from entering the drive unit housing.

12. The micro valve according to claim 10 , wherein the external dimensions of the micro valve amount to approximately 5 mm x 5 mm x 5 mm.

13. The micro valve according to claim 10 , wherein the one-piece transmission element extends from a first end to a second end, the first end comprising a shaft portion with a distal end that selectively engages the at least one valve seat and the second end comprising an enlarged flange portion that abuts directly against the at least one shape memory alloy element.

14. The micro valve according to claim 13 , wherein the enlarged flange portion includes a recess that receives one end of the spring.

15. The micro valve according to claim 13 , wherein the drive unit housing includes an inwardly protruding support that receives an end of the spring.

16. The micro valve according to claim 13 , wherein the enlarged flange portion includes a recess that receives one end of the spring, and wherein the drive unit housing includes an inwardly protruding support that receives an opposite end of the spring.

17. A micro valve that is a normally closed micro valve. comprising:
a fluid housing;
at least one valve seat;
a sealing element directly interacting with the at east one valve seat to seal fluid within the fluid housing;
a drive unit comprising a drive unit housing separated from the fluid housing by the sealing element which prevents fluid from entering the drive unit housing, a spring, and at least one shape memory alloy element which is attached to the drive unit housing in a deflectable manner, is loaded by the spring towards a deflected position, and is movable in response to a temperature increase, and the shape memory effect activated thereby, into a position which is at least less deflected against an increasing load by the spring;
wherein the shape memory alloy element cooperates with the sealing element and exerts an operating force on the sealing element for closing and opening the valve seat with or against a compression spring force;
wherein the at least one shape memory alloy element comprises at least one pair of foils stacked upon each other which are connected to each other at an outer perimeter at least in sections and are biased by the spring into the deflected position, and wherein the foils include a central passage through which the spring or a transmission element cooperating with the spring extends, and wherein the transmission element is formed as one-piece; and
wherein the at least one shape memory alloy element is concentric with the spring, and wherein the at least one shape memory alloy element is positioned radially outwardly of the spring.

18. A drive unit for a micro valve comprising:
a housing;
a spring;
at least one shape memory alloy element which is attached to the housing in a deflectable manner, is loaded by the spring towards a deflected position, and is movable in response to a temperatur

Assignees

• Stadelbauer Birgit
• Beck Klaus-Guenther
• Buerkert Werke Gmbh

Inventors

• Stadelbauer Birgit
• Beck Klaus-Guenther

Classifications

• F16K99/0044

  using thermo-electric means · CPC title

• F16K31/025

  actuated by thermo-electric means · CPC title

• F16K31/002

  actuated by temperature variation (thermo-electric F16K31/025) · CPC title

• C08L2201/12

  Shape memory · CPC title

• F16K99/0038

  using shape memory alloys · CPC title