Detector of inflation pressure of tires of a vehicle

• US 4,790,179 A
• Filed: 08/07/1987
• Issued: 12/13/1988
• Est. Priority Date: 12/12/1985
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Haas, Lothar, Hettich, Gerhard, Schmid, Hans-Dieter
• Primary Examiner(s): WOODIEL, DONALD
• Application Number:
  US07/105,301
• Time in Patent Office: 494 Days
• Field of Search: 73/146.5, 340/58, 336/30
• US Class Current: 73/146.5
• CPC Class Codes: B60C 23/0428 using passive wheel mounted resonance circuits
• CPC Class Codes: B60C 23/043 using transformer type signal transducers, e.g. rotary transformers
• CPC Class Codes: B60C 23/0498 for rim attachments B60C23/0494, B60C23/0496 take precedence

Abstract

A tire pressure detector for motor vehicles which is to be fastened at the circumference of a wheel rim and comprises an oscillating circuit having coupling coil which cooperates with a stationary receiver coil. In order to increase the minimum air gap between the rotating coupling coil and the stationary receiver coil, the coupling coil, which rotates with the wheel rim, is arranged on a middle limb of a plate-shaped ferrite core. The magnetic coupling for the stationary receiver coil is improved by means of the shape of the ferrite core (23).

Claims

1. In a tire pressure detector for motor vehicles, comprising an electric oscillating circuit having a coupling coil;

a pressure element connected with said circuit in series and acted upon by air pressure in a vehicle tire, the oscillating circuit being fastened at a circumference of a wheel rim;

a signal receiver including a signal receiver coil (31), wherein the coupling coil, which revolves with the wheel rim, cooperates with said receiver coil which is located opposite said coupling coil and is arranged in the area of the wheel rim so as to be stationary and sense the oscillation of the oscillating circuit; and

an evaluting circuit connected to said signal receiver coil, the improvement comprising a plate-shaped ferrite core (23) having a middle limb (22), the coupling coil (18) being arranged on the middle limb (22) of the plate-shaped ferrite core (23).

2. Tire pressure detector according to claim 1, further including a housing, and a magnetically inert supporting part (25) received in said housing wherein the middle limb (22) has an axially continuous opening (24) at which the magnetically inert supporting part (25) is received by the ferrite core (23).

3. Tire pressure detector according to claim 2, wherein said signal receiver further includes a plate-shaped ferrite core (33) including a middle limb (32), said signal receiver coil (31) being arranged on the middle limb (32) of the plate-shaped ferrite core (33).

4. Tire pressure detector according to claim 1, wherein said signal receiver further includes a plate-shaped ferrite core (33) including a middle limb (32), said signal receiver coil (31) being arranged on the middle limb (32) of the plate-shaped ferrite core (33).