Abstract: A variable reluctance sensor assembly including an open-ended housing which contains a bobbin assembly with an overmolded connector piece. The bobbin contains a ferrous pole piece pressed into a closed-ended cavity within the bobbin, a small disc-shaped rare earth permanent magnet mounted forward of the pole piece, and a magnet wire coil wound upon the bobbin barrel and attached to the customer terminals which carry the output signal. A separate submersible connector is affixed to the integral connector. A front seal ring is stretch fit to the forward flange of the bobbin, and a rear seal ring is stretch fit to the rear section of the sensor housing. The bobbin assembly is slip fit into the housing with magnet forward.

Abstract: A variable reluctance sensor including a close-ended hollow housing which contains and thereby protects the operative components of the sensor. The sensor includes a bobbin portion interconnected with a connector member attachable to a submersible connector. An elongated pole piece extends through a bore in the bobbin barrel and press fits into a cavity in the connector member. A magnet is disposed at the end of the pole piece, and a magnet wire coil is wound around the bobbin barrel and electrically connected with conductors in the connector member. An outer hollow housing, which surrounds the bobbin portion, includes an open end portion which is ultrasonically welded to the connector member. After ultrasonic assembly of the housing to the connector member, the magnet rests against the opposite, close-ended portion of the housing. In an alternative embodiment, the housing and bobbin portion may be keyed to ensure proper assembly, and further a leaded sensor may be provided.

Abstract: A method of securing the bobbin assembly of a variable reluctance sensor within a hollow sensor shell having an opening in the front wall thereof to permit the magnet of the bobbin assembly to be exposed therethrough. A welding apparatus is provided for automatically ultrasonically welding the rear portion of the bobbin assembly to the open rear end portion of the shell, thereby preventing fluid flow through the rear end of the shell. The welding process forces the bobbin assembly into the sensor shell sufficiently to compress the front elastomeric seal between the front flange of the bobbin assembly and the inner surface of the front wall of the shell.

Abstract: A variable reluctance sensor assembly including an open-ended housing which contains a bobbin assembly with an overmolded connector piece. The bobbin contains a ferrous pole piece pressed into a closed-ended cavity within the bobbin, a small disc-shaped rare earth permanent magnet mounted forward of the pole piece, and a magnet wire coil wound upon the bobbin barrel and attached to the customer terminals which carry the output signal. A separate submersible connector is affixed to the integral connector. A front seal ring is stretch fit to the forward flange of the bobbin, and a rear seal ring is stretch fit to the rear section of the sensor housing. The bobbin assembly is slip fit into the housing with magnet forward.

Abstract: A variable reluctance sensor assembly including an open-ended housing which contains a bobbin assembly with an overmolded connector piece. The bobbin contains a ferrous pole piece pressed into a closed-ended cavity within the bobbin, a small disc-shaped rare earth permanent magnet mounted forward of the pole piece, and a magnet wire coil wound upon the bobbin barrel and attached to the customer terminals which carry the output signal. A separate submersible connector is affixed to the integral connector. A front seal ring is stretch fit to the forward flange of the bobbin, and a rear seal ring is stretch fit to the rear section of the sensor housing. The bobbin assembly is slip fit into the housing with magnet forward.