The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 18, 1990
Filed:
Jul. 14, 1989
Noboru Tsuboi, Kakogawa, JP;
Kabushiki Kaisha Kobe Seiko Sho, Kobe, JP;
Abstract
A vertical oilless screw vacuum pump for effective use in industrial processes to which air containing oil is detrimental, such as vacuum food packaging processes and semiconductor device manufacturing processes. The vertical oilless screw vacuum pump includes a pump unit having a pump casing provided with a suction port in the upper portion and a discharge port in the lower portion thereof, and a set of meshed male and female oilless screw rotors disposed within the pump casing A, also high-frequency motor is disposed under the pump unit and has a motor casing joined to the lower end of the pump casing. The output shaft of the motor is coupled directly with one of the rotor shafts of the oilless screw rotors to drive the oilless screw rotors directly without using any gear train. Bearings supporting the upper ends of the rotor shafts are lubricated by a grease having a vapor pressure below a desired ultimate vacuum to be achieved by the vertical oilless screw vacuum pump. The motor casing is used also as an oil reservoir for containing a lubricating oil for lubricating bearings supporting the lower ends of the rotor shafts. The use of the grease for lubricating the bearings disposed near the suction ports avoids the dispersion of oil into a vacuum. The direct coupling of the rotor shaft and the output shaft of the motor, and the use of the motor casing as an oil reservoir enables the vertical oilless screw vacuum pump to be constructed in a compact construction.