Plastic vane for a vane-cell vacuum pump
AssigneeRobert Bosch GmbH
InventorsWolfram Hasert, Leonardo Cadeddu, Monica Pilone
Life of this patent
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Abstract
A vane cell vacuum pump has a rotor, in which a plastic vane, which with at least terminal part engages the inner wall of the jacket of a pump housing, is guided longitudinally. The body of the vane comprises a duroplastic and is united with the terminal part, of thermoplastic by an injection-molding operation. With the material comprising the body, high mechanical strength is attained, while with the material of the terminal part, high wear resistance and a low coefficient of friction are attained.
Claims9
In a vane (15) of plastic for a vane cell vacuum pump (10), which vane is guided longitudinally in a rotor (13) and with at least one terminal part (22, 23) slidingly engages the inner wall (16) of the jacket of a pump housing (11), the body (21) of the vane (15) and its terminal part (22, 23) comprising different materials, of which the material comprising the terminal part (22, 23) has a high wear resistance, the improvement wherein the body (21) of the vane (15) comprises a duroplastic, and its terminal part (22, 23) comprises a thermoplastic, which plastics are joined together by an injection-molding operation to form a rigid vane structure.
A method of producing a plastic vane for a vane cell vacuum pump of the type having a pump body and a jacket in which the vane is guided longitudinally in a rotor, the method comprising
- initially forming an elongated vane body from a duroplastic material, the vane body having at least one end portion having at least one undercut groove formed therein, and
- subsequently forming a terminal end portion onto each said at least one end portion, each said terminal end portion being formed by injection molding from a thermoplastic having a high wear resistance and a relatively low coefficient of friction, whereby the thermoplastic material flows into each said at least one undercut groove to form a rigid unitary structure.
Dependencies are inferred from the claim text.