Tire pressure sensor for motor vehicles
First Claim
1. In a tire pressure sensor for motor vehicles, comprising a pressure switch for monitoring tire pressure, said pressure switch being fastened at a circumference of a wheel rim and being actuated by the tire pressure, said pressure switch including a reference pressure chamber;
- a diaphragm, said reference pressure chamber being closed in the direction of the tire by said diaphragm which is electrically conductive;
an element enclosing said reference pressure chamber;
a contact pin supported in said element and engageable with a middle area of the diaphragm for closing an electric circuit when there is sufficient air pressure in the tire;
the improvement comprising an air gap (X) provided between the contact pin (30) and the middle area of the diaphragm (29) for testing leakage of the reference pressure chamber (21a) when an equal pressure occurs on both sides of the diaphragm (29), the element enclosing the reference pressure chamber being fastened in a sensor housing (16), which is fixed in the wheel rim (12) and closed toward outside, in such a manner that it is surrounded by the compressed air in the tire (11).
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Accused Products
Abstract
A tire pressure sensor for motor vehicles comprises a pressure switch which is actuated by the tire pressure for monitoring the tire pressure. The pressure switch has a reference pressure chamber which is closed in the direction of the tire by means of an electrically conducting diaphragm and carries a contact pin which is contacted by the middle area of the diaphragm in order to close an electric circuit when there is sufficient air pressure in the tire. In order to trigger an alarm signal during a leak in the reference pressure chamber a leakage check of the reference pressure chamber is realized in that an air gap is located between the contact pin and the middle area of the diaphragm when there is equal pressure on both sides of the diaphragm.
25 Citations
6 Claims
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1. In a tire pressure sensor for motor vehicles, comprising a pressure switch for monitoring tire pressure, said pressure switch being fastened at a circumference of a wheel rim and being actuated by the tire pressure, said pressure switch including a reference pressure chamber;
- a diaphragm, said reference pressure chamber being closed in the direction of the tire by said diaphragm which is electrically conductive;
an element enclosing said reference pressure chamber;
a contact pin supported in said element and engageable with a middle area of the diaphragm for closing an electric circuit when there is sufficient air pressure in the tire;
the improvement comprising an air gap (X) provided between the contact pin (30) and the middle area of the diaphragm (29) for testing leakage of the reference pressure chamber (21a) when an equal pressure occurs on both sides of the diaphragm (29), the element enclosing the reference pressure chamber being fastened in a sensor housing (16), which is fixed in the wheel rim (12) and closed toward outside, in such a manner that it is surrounded by the compressed air in the tire (11). - View Dependent Claims (2, 3, 4, 5, 6)
- a diaphragm, said reference pressure chamber being closed in the direction of the tire by said diaphragm which is electrically conductive;
Specification