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:
Jul. 21, 1998
Filed:
Jun. 26, 1995
Yoshihiro Ikemoto, Hirakata, JP;
Teruo Maruyama, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Abstract
A vacuum pump includes a plurality of rotors of different outer diameters accommodated in a housing so that a fluid transportation space is defined by the housing and the plural rotors. Rotary shafts are integrally formed with the respective rotors and a first motor, which is a high frequency motor, for driving the rotary shaft of the smaller diameter rotor as a driving shaft. A second motor, which is an AC servo motor or pulse motor, is provided for driving the other rotary shaft as a driven shaft. A rotation detecting device is provided adjacent each shaft for detecting rotating angles and/or rotating speeds of the first and second motors. Also provided is a fluid suction port and a fluid discharge port which are formed in the housing, and a control device for controlling rotation of the driven shaft based on data from the rotation detecting device so as to synchronize the rotation of the driven shaft driven by the second motor with that of the driving shaft driven by the first motor.