Pneumatic valve

Patent metadata

Field	Value
Publication number	US-11047497-B2
Application number	US-201716463437-A
Country	US
Kind code	B2
Filing date	Dec 14, 2017
Priority date	Dec 20, 2016
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A pneumatic valve including an air chamber with an air connection, and an actuator with a movable shut-off element and with an SMA element composed of a shape memory alloy. The SMA element is mechanically coupled to the movable shut-off element, wherein, for the activation of the actuator, electrical heating power is fed to the SMA element, after which the SMA element deforms and brings about a predefined movement of the shut-off element for opening or closing the air connection. The actuator includes a detection unit to detect the arrival at and departure from an end position of the shut-off element when the actuator is activated. The actuator includes a control device which is configured such that, when the actuator is activated, the control device detects the current cycle time between a departure from and the next arrival at the end position by the shut-off element.

First claim

The invention claimed is:

1. A pneumatic valve comprising an air chamber with an air connection, and comprising an actuator with a movable shut-off element and an SMA element composed of a shape memory alloy, which SMA element is mechanically coupled to the movable shut-off element, wherein, for activation of the actuator, electrical heating power can be fed to the SMA element, after which the SMA element deforms and as a result brings about a predefined movement of the shut-off element for adjusting the shut-off element during micro-switching processes between opening or closing the air connection, wherein, when the supply of electrical heating power is ended, the deformation of the SMA element is reversed and as a result brings about a reversal of the predefined movement of the SMA element,
wherein the actuator comprises a detection unit to detect the arrival at and departure from an end position of the shut-off element when the actuator is activated,
wherein the actuator contains a control device which is configured in such a way that, when the actuator is activated, said control device sets the electrical heating power to a first power value if according to the detection of the detection unit the shut-off element is not in an end position and a stroke of the shut-off element is greater than zero, and, when the actuator is activated, said control device sets the electrical heating power to a second power value which is lower than the first power value if according to the detection of the detection unit the shut-off element is in the end position, and
wherein the control device is also configured in such a way that, when the actuator is activated, said control device detects a current cycle time between the departure from and a next arrival at the end position by the shut-off element, or detects a measure of the current cycle time, and reduces a difference between the first and second power values if the current cycle time undershoots a first setpoint cycle time, and increases the difference between the first and second power values if the current cycle time exceeds a second setpoint cycle time which is longer than or equal to the first setpoint cycle time.

2. The pneumatic valve as claimed in claim 1 , wherein the first setpoint cycle time and/or the second setpoint cycle time is between 10 ms and 100 ms.

3. The pneumatic valve as claimed in claim 2 , wherein the reduction and the increasing of the difference between the first and second power values are brought about by exclusively changing the first power value or by exclusively changing the second power value or by changing both the first and the second power values.

4. The pneumatic valve as claimed in claim 1 , wherein the reduction and the increasing of the difference between the first and second power values are brought about by exclusively changing the first power value or by exclusively changing the second power value or by changing both the first and the second power values.

5. The pneumatic valve as claimed in claim 1 , wherein the reduction and the increasing of the difference between the first and second power value take place in a chronologically continuous or chronologically discreet fashion.

6. The pneumatic valve as claimed in claim 1 , wherein the actuator is configured in such a way that, when the end position of the shut-off element is reached, the resistance of a section of the SMA element is electrically bypassed by means of a bypass section, and as a result the resistance of the SMA element is decreased, wherein the detection unit is designed to detect the decreasing of the resistance of the SMA element by means of a resistance measurement, as a result of which the arrival at the end position of the shut-off element is detected, and to detect the ending of the decreasing of the resistance of the SMA element as a result of which the departure from the end position of the shut-off element is detected.

7. The pneumatic valve as claimed in claim 6 , characterized in that the actuator is configured in such a way that the deformation of the SMA element brings about a relative movement between the bypass section and the SMA element, wherein, when the end position of the shut-off element is reached, the relative movement brings about the electrical bypassing of the resistance of the section of the SMA element.

8. The pneumatic valve as claimed in claim 6 , wherein the actuator comprises an electrically conductive element, in the form of a plate or a web, wherein the electrically conductive element is rigidly connected to the shut-off element or forms a part of the shut-off element, and wherein the bypass section is contained in the electrically conductive element.

9. The pneumatic valve as claimed in claim 1 , wherein the shut-off element is a valve flap which executes, as a predefined movement for opening or closing the air connection, a tilting action, wherein the tilting action is brought about by elastic bending and/or by rotation of the valve flap.

10. The pneumatic valve as claimed in claim 1 , wherein the SMA element is an SMA wire which is contracted by feeding in the electrical heating current, and as a result brings about the predefined movement of the shut-off element, wherein the SMA wire runs in a plane.

11. The pneumatic valve as claimed in claim 10 , wherein the SMA wire comprises a first and a second wire section, between which a coupling section of the SMA wire is located, wherein the coupling section is coupled mechanically to the shut-off element.

12. The pneumatic valve as claimed in claim 11 , wherein the actuator comprises an electrically conductive element in the form of a plate or a web, wherein the electrically conductive element is rigidly connected to the shut-off element or forms a part of the shut-off element, and wherein a bypass section is contained in the electrically conductive element and wherein the electrically conductive element is arranged in such a way that, when the end position of the shut-off element is reached, the conductive element touches the first wire section and the second wire section, in each case at a contact point, and as a result brings about the electrical bypassing of the resistance of the section of the SMA element.

13. The pneumatic valve as claimed in claim 11 , wherein the actuator comprises an electrically conductive component, in the form of a line, wherein the electrically conductive component has a fixed position in the valve, and wherein a bypass section is contained in the electrically conductive component.

14. The pneumatic valve as claimed in claim 13 , wherein the electrically conductive component is a line, one end of which is electrically connected to the SMA element and the other end of which comprises a contact point which, when the end position of the shut-off element is reached, comes into contact with the SMA element and as a result brings about the electrical bypassing of the resistance of the section of the SMA element.

15. The pneumatic valve as claimed in claim 14 wherein the SMA wire comprises a first and a second wire section, between which a coupling section of the SMA wire is located, wherein the coupling section is coupled mechanically to the shut-off element, and wherein at least part of the line between the first and second wire section extends in the direction of the coupling section of the SMA wire.

16. The pneumatic valve as claimed in claim 1 , wherein the valve is provided for filling and/or emptying at least one elastic air bladder in a device for pneumatically adjusting a seat in a means of transportation.

17. The pneumatic valve as claim

Assignees

• Conti Temic Microelectronic Gmbh

Inventors

• Beuschel Michael
• Bauer Stefan

Classifications

• F03G7/066

  Actuator control or monitoring · CPC title

• F03G7/06143

  Wires · CPC title

• F16K37/0041

  for measuring valve parameters (F16K37/0033 takes precedence) · CPC title

• F16K31/025 Primary

  actuated by thermo-electric means · CPC title

• F03G7/065

  using a shape memory element · CPC title