Heat sensitive actuator device

Patent metadata

Field	Value
Publication number	US-10563639-B2
Application number	US-201515509289-A
Country	US
Kind code	B2
Filing date	Sep 8, 2015
Priority date	Sep 15, 2014
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

A heat sensitive actuator uses a shape memory material layer which is thermally stimulated to change shape, in response to a rise in temperature, from a first shape at a first temperature to a second shape at a second temperature. A layer stack is associated with the shape memory material layer, and it can adopt the first shape at the first temperature. In this way, the layer stack is used to return the shape memory material to its original shape after cooling.

First claim

The invention claimed is:

1. An actuator device having an actuator member, the actuator member being configured to define at least a first actuation state of the actuator device and a second state of the actuation device, the second state being different from the first state, the actuator member comprising:
a layer stack comprising a first layer and a second layer attached to each other for operating like a bimetallic strip upon heating and cooling of the actuator device, the first and second layers having different coefficients of thermal expansion and not being pre-stressed, and
a shape memory material layer that is not pre-stressed, and is directly attached to an external surface of the layer stack, the shape memory material layer comprising or consisting of one or more one-way shape memory materials, the shape memory material layer being configured to change shape from a first shape at a first temperature to a second shape at a second temperature higher than the first temperature, the first shape being associated with the first actuation state and the second shape being associated with the second actuation state,
wherein the first temperature is associated with a martensite state of the shape memory material layer and the second temperature is associated with an austenite state of the shape memory material layer, and
wherein the layer stack is configured, through thermal contraction of the first and second layers of the layer stack, to return the shape memory material layer from the second shape to the first shape upon a temperature change of the actuator device from the second temperature to the first temperature.

2. The actuator device as claimed in claim 1 , wherein the first temperature is below the phase change temperature of at least one of the at least one shape memory materials and the second temperature is above the phase change temperature of the at least one of the at least one shape memory materials.

3. The actuator device as claimed in claim 1 , wherein the shape memory material layer has a coefficient of thermal expansion that is between the coefficients of thermal expansion of the first layer and the second layer.

4. The actuator device as claimed in claim 3 , wherein the shape memory material layer is directly attached to only the second layer and not directly attached to the first layer.

5. The actuator device as claimed in claim 3 , wherein the first shape and/or the second shape are bent shapes in a stack direction of the layer stack and either
the first shape is a less bent shape than the second shape, the first layer is at an outer side of the second shape and the first layer has a higher coefficient of thermal expansion than the second layer, or
the first shape is a more bent shape than the second shape, the first layer is at an inner side of the shape memory material layer and the first layer has a higher coefficient of thermal expansion than the second layer.

6. The actuator device as claimed in claim 1 , further comprising a heater device for heating at least the shape memory material layer and/or a cooling device for cooling at least the shape memory material layer.

7. The actuator device as claimed in claim 1 , wherein the first shape and the second shape each comprise coiled spring shapes with different degrees of spring expansion, wherein the coiled spring has a central axis and wherein the layers are stacked along the central axis direction.

8. An apparatus comprising the actuator device as claimed in claim 1 , wherein at least part of the apparatus is controlled by the actuator device.

9. The apparatus as claimed in claim 8 , wherein the apparatus comprises a circuit including the actuator device, wherein the actuator device operates as a switch.

10. The apparatus as claimed in claim 8 , wherein the apparatus is a lighting device.

11. The apparatus as claimed in claim 8 , wherein the apparatus is a part of, or is a motor, wherein the actuator device is part of a valve for control of fluid used with the motor when in operation.

12. An actuation method, comprising acts of:
providing a shape memory material layer without pre-stressing and comprising or consisting of at least one one-way shape memory material;
providing a layer stack having an external surface directly attached to the shape memory material layer, the layer stack comprising a first layer and a second layer attached to each other for operating like a bimetallic strip upon heating and cooling, the first and second layers having different coefficients of thermal expansion and not being pre-stressed;
heating the actuator device to thereby change the temperature of at least the shape memory material layer from a first temperature to a second temperature higher than the first temperature to thereby change the shape of the shape memory material layer from a first shape to a second shape, the first shape being associated with a first actuation state of the actuation device and the second shape being associated with a second actuation state of the actuation device, wherein the first temperature is associated with a martensite state of the shape memory material layer and the second temperature is associated with an austenite state of the shape memory material layer;
cooling the actuator device, to thereby change the temperature of at least the layer stack from the second temperature to the first temperature to cause the layer stack to return the shape memory material layer from the second shape to the first shape, through thermal contraction of the first and second layers of the layer stack.

13. The method as claimed in claim 12 , comprising an act of configuring the first actuation state and the second actuation state to control flow of electricity, liquid or gas based on temperature or heat change.

14. The method as claimed in claim 12 , wherein providing the shape memory material layer and the layer stack comprises acts of providing the shape memory material layer with a coefficient of thermal expansion that is between the coefficients of thermal expansion of the first layer and the second layer.

15. The method as claimed in claim 12 , wherein providing the shape memory material layer and the layer stack comprises acts of: providing the first shape and the second shape each as coiled spring shapes with different degrees of spring expansion, the coiled spring having a central axis; and stacking the layers along the central axis direction.

16. An actuator device having an actuator member, the actuator member being configured to define at least a first actuation state of the actuator device and a second state of the actuation device, the second state being different from the first state, the actuator member comprising:
a layer stack comprising a first layer and a second layer attached to each other for operating like a bimetallic strip upon heating and cooling of the actuator device, the first and second layers having different coefficients of thermal expansion, the first layer not being pre-stressed, and
a shape memory material layer comprising the second layer or a separate layer, and

comprising or consisting of one or more shape memory materials, the shape memory material layer being configured to change shape from a first shape at a first temperature to a second shape at a second temperature higher than the first temperature, the first shape being associated with the first actuation state and the second shape being associated with the second actuation state,
wherein the layer stack is configured, through thermal contraction of the layers of the layer stack, to return the shape memory material layer fr

Assignees

• Koninklijke Philips Nv

Inventors

• Van Den Aker Karel Johannes Adrianus

Classifications

• F03G7/065 Primary

  using a shape memory element · CPC title

• F03G7/06145 Primary

  Springs · CPC title

• F03G7/0613

  using layers of different materials joined together, e.g. bimetals · CPC title

• F03G7/0614 Primary

  using shape memory elements · CPC title