Method for cleaning electrical contacts of an electrical switching device and motor vehicle

Abstract

A method for cleaning electrical contacts of an electrical switching device includes displacing a first electrical contact element and a second electrical contact element of an electrical contact relative to each other so that the first electrical contact element and the second electrical contact element are in a closed position; and when the first and second electrical contact elements are in the closed position applying a waveform on the electrical contact so that the first contact element and the second contact element are excited to undergo a mechanical vibration relative to each other.

Claims

1. A method for cleaning electrical contacts of an electrical switching device, said method comprising: displacing a first electrical contact element and a second electrical contact element of an electrical contact relative to each other so that the first electrical contact element and the second electrical contact element are in a closed position; and when the first and second electrical contact elements are in the closed position, applying an electrical waveform using a control device so that the first contact element and the second contact element are excited to undergo a mechanical vibration relative to each other without leaving the closed position.

2. The method of claim 1, wherein during operation of the electrical switching device, the electrical waveform is superimposed on an electrical current.

3. The method of claim 2, wherein the electrical current is an operating current.

4. The method of claim 1, wherein the electrical waveform is generated with at least one frequency, which is suited to generate mechanical vibrations at a natural frequency of the electrical contact.

5. The method of claim 1, wherein the electrical waveform is generated with a frequency, which corresponds to a multiple of the natural frequency of the electrical contact.

6. The method of claim 1, wherein the natural frequency is determined by applying white noise on the electrical contact.

7. The method of claim 1, wherein the electrical switching device is configured as a contactor or as a relay.

8. The method of claim 1, wherein the electrical switching device is configured as a switching device for a motor vehicle.

9. The method of claim 1, wherein the electrical switching device is configured as a switching device for an onboard electronics of a motor vehicle.

10. The method of claim 1, wherein the contact elements of the electrical contact, have a geometric shape in a contact region, which causes a point contact or a line contact of the contact elements in the closed position.

11. The method of claim 1, wherein at least one of the first and second contact elements is supported for movement in the closed position.

12. The method of claim 1, wherein at least one of the first and second contact elements is supported elastically in the closed position.

13. A motor vehicle, comprising: an electrical switching device, said electrical switching device including an electrical contact, said electrical contact having a first electrical contact element and a second electrical contact element, said first and second electrical contact element being displaceable relative to each other between an open position and a closed position; and a control device configured to apply an electrical waveform on the electrical contact when the when the first and second electrical contact elements are in the closed position so that the first contact element and the second contact element are excited to undergo a mechanical vibration relative to each other without leaving the closed position.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which the sole FIGURE shows a schematic representation of an electrical switching device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(2) Throughout all the FIGURES, same or corresponding elements may generally be indicated by same reference numerals. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figures are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.

(3) The FIGURE shows a schematic representation of an electrical switching device 1, which in the present case is arranged in a higher order electrical device 3, for example an onboard electronics of the motor vehicle 5. The electrical switching device 1 hereby serves in particular for switching electrical power and is particularly preferably configured as a contactor or as a relay.

(4) The electrical switching device 1 is electrically connected with an electrical power source 7, which is preferably configured as a direct voltage source or as a direct current source, and is configured to connect an electrical load 9 or sink, in particular a user, with the electrical power source 7 in a first switching position and to disconnect these components from the power source 7 in a second switching position.

(5) For this purpose the electrical switching device 1 has at least one electrical contact 11, which has a first contact element 13 and a second contact element 15. These are displaceable relative to each other into an open position and into a closed position so that the electrical contact 11 can be opened and closed. Hereby the open position of the contact elements 13, 15 corresponds to a switching position of the electrical switching device 1 in which the electrical load 9 is separated from the power source 7, wherein the closed position of the contact elements 13, 15 corresponds to a switching position of the electrical switching device 1 in which the electrical load 9 is electrically connected with the electrical power source 7.

(6) A waveform generating means 17 is provided, which is preferably configured as an alternating current source and which is operatively connected with the contact elements 13, 15 so that an electrical waveform, in particular an alternating voltage, can be applied to the contact elements so that the contact elements 13, 15 are excited for mechanical vibration relative to each other.

(7) Further a control device 19 is provided which is configured to control the waveform generating means 17 so that the waveform generating meansin particular in predetermined time intervalsas need or otherwise can generate an electrical waveform which can be applied to the contact elements 13, 15 for exciting the contact elements to undergo mechanical movements relative to each other.

(8) The waveform generating means 17 is in particular electrically connected with the electrical switching device 1 so that the electrical waveform, which is generated by the waveform generating means 17, is superimposed during operation of the switching device 1 with an electrical current generated by the electrical power source 7.

(9) The electrical waveform is preferably generated by the waveform generating means 17 with at least one frequency, which is suited to generate mechanical vibrations at a natural frequency of the electrical contact 11. Particularly preferably the electrical waveform is hereby generated with a frequency, which corresponds to the natural frequency or a multiple of the natural frequency of the electrical contact 11. It is possible that this natural frequency is determined once or multiple times by applying white noise by means of the waveform generating means 17 on the electrical contact 11.

(10) Excitation of the electrical contact elements 13, 15 to undergo mechanical vibrations relative to each other in particular causes the contact elements to undergo higher frequency transverse vibrations, in particular in the kHz range, whereby the contact elementswithout leaving the closed positionare quickly and effectively cleaned.

(11) The contact elements 13, 15 in particular have a geometrical shape in a contact region, which causes a point contact or a line contact of the contact elements 13, 15 in the closed position. Hereby it is in particular possible that at least one of the contact elements 13, 15 is configured convex in the contact region. It is further possible that at least one of the contact elements 13, 15 is supported movable, in particular elastically, in the closed position.

(12) Overall it can be see that the method and the motor vehicle allow a very efficient and at the same time gentle cleaning, in particular of power contacts of an electrical switching device so that ageing-related wear can be attenuated or even reversed without the cleaning having an adverse effect on the service life of the electrical switching device.

(13) Hereby in particular a self-cleaning of the electrical contact is performed based on an electromagnetic repulsion.

(14) What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims and includes equivalents of the elements recited therein: