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Robust Oil Pump For Electric, Hybrid and Fuel Cell Vehicle Applications

IP.com Disclosure Number: IPCOM000029457D
Publication Date: 2004-Jun-29
Document File: 2 page(s) / 15K

Publishing Venue

The IP.com Prior Art Database

Abstract

Lubrication of gears and bearings in a planetary gearbox or transmission generally requires an oil pump to overcome centrifugal force and supply oil to the centerline of the rotating components. Mechanically driven oil pumps are commonly used in the planetary automatic transmissions and also in the internal combustion engines of conventional vehicles. These pumps operate continuously and therefore consume energy continuously.

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Robust Oil Pump For Electric, Hybrid and Fuel Cell Vehicle Applications

Problem:  Electric oil pumps used in Electric Vehicles (EV) must survive hostile environments that include high/low temperatures, immersion in oil, and severe duty cycles. These conditions my potentially cause damage and premature motor/pump failure.

Description of Invention:

Lubrication of gears and bearings in a planetary gearbox or transmission generally requires an oil pump to overcome centrifugal force and supply oil to the centerline of the rotating components.  Mechanically driven oil pumps are commonly used in the planetary automatic transmissions and also in the internal combustion engines of conventional vehicles. These pumps operate continuously and therefore consume energy continuously.

Recently, electric vehicles using planetary gearboxes have been equipped with oil pumps driven by flow-thru electric motors.  These oil pumps have carried on the practice of operating on a continuous (100%) duty cycle.  Flow-thru motors route the circulating oil thru the motor assembly to provide lubrication and cooling.  The disadvantage of flow-thru motors is that the same fluid that lubricates the planetary gearbox also flows thru the oil pump drive motor. This allows the transfer of contaminants and any corrosive properties in the oil to the pump drive motor assembly. These contaminants may form deposits on the commutator and the brushes. These contaminants also include ferrous materials that may interfere with the armature air gap and cause magnetic and electrical short circuits in the motor.

Toprevent these problems, we propose the use of a hermetically sealed electric motor assembly and operating the motor at less than 100% duty cycle.

·        The sealing of the motor will prevent problems of brush bounce, oil contaminants inside the motor assembly, and corrosive effects caused by exposin...