Method for monitoring flexural vibrations of a piezoactuator

• US 9,070,879 B2
• Filed: 09/02/2011
• Issued: 06/30/2015
• Est. Priority Date: 09/03/2010
• Status: Active Grant

• Current Assignee: Epcos AG (TDK Corporation)
• Original Assignee: Epcos AG (TDK Corporation)
• Inventors: Gabl, Reinhard
• Primary Examiner(s): TRINH, MINH N
• Application Number:
  US13/813,341
• Publication Number:
  US 20130212848A1
• Time in Patent Office: 1,397 Days
• Field of Search: 29/253.5, 295/93, 295/94, 333/187, 310329-331
• US Class Current: 1/1
• CPC Class Codes: G01H 1/04 of vibrations which are transverse to direction of propagation
• CPC Class Codes: G01R 29/22 Measuring piezoelectric properties
• CPC Class Codes: H10N 30/03 Assembling devices that include piezoelectric or electrostrictive parts
• CPC Class Codes: H10N 30/88 Mounts; Supports; Enclosures; Casings
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

In the method for monitoring flexural vibrations of a piezoactuator, a small-signal spectrum of a piezoactuator, which is provided and mounted for the purpose of exciting longitudinal vibrations, is measured and an excitation of a transverse vibration in the piezoactuator is detected from resonances occurring in the small-signal spectrum.

Claims

1. A method for monitoring flexural vibrations of a piezoactuator, the method comprising:

providing a mounting for the piezoactuator;

applying an AC voltage exciting longitudinal vibrations in the piezoactuator;

measuring a small-signal spectrum of the piezoactuator when the longitudinal vibrations are excited;

monitoring an excitation of a transverse vibration in the piezoactuator from resonances occurring in the small-signal spectrum; and

changing the mounting of the piezoactuator in the case of an occurrence of an undesirably strong transverse vibration.

2. The method according to claim 1, wherein

the piezoactuator is mounted between holders in a longitudinal direction in which the longitudinal vibrations are excited;

the measurement of the small-signal spectrum and the change to the mounting are repeated as required until it is detected from resonances in the small-signal spectrum that no transverse vibration, or at most a transverse vibration below a prescribed limit, is excited.

3. The method according to claim 2, wherein the measurement and the change in the mounting are repeated until resonances occur in the small-signal spectrum possibly at a prescribed minimum frequency spacing.

4. The method according to claim 2, wherein the measurement and the change in the mounting are repeated until no resonances occur in the small-signal spectrum.

5. The method according to claim 2, wherein the measurement and the change in the mounting are repeated until any resonances that occur in the small-signal spectrum are above a prescribed minimum frequency.

6. The method according to claim 2, wherein a position and/or an angle of the piezoactuator with reference to the holders is changed in order to change the mounting.

7. The method according to claim 2, wherein a mechanical stress exerted by the holders on the piezoactuator is changed in order to change the mounting.

8. The method according to claim 1, wherein an absolute value of an impedance of the piezoactuator is measured as small-signal spectrum as a function of a frequency of an applied AC voltage.

9. The method according to claim 8, wherein parallel resonances and series resonances of the piezoactuator are determined.

10. The method according to claim 1, wherein the measurement and evaluation of the small-signal spectrum are carried out by using an electronic control loop.

11. The method according to claim 1, wherein the mounting is installed or mounted in an engine provided for a motor vehicle.