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:
Jan. 20, 2004
Filed:
Oct. 29, 2002
Michael W. Barto, Shakopee, MN (US);
Mark D. Schuster, Wahpeton, ND (US);
John B. Heckel, Shakopee, MN (US);
Marvin L. Bernstrom, Eden Prairie, MN (US);
Eaton Corporation, Cleveland, OH (US);
Abstract
A two-speed gerotor motor ( ) including motor valve means ( ) to communicate fluid to and from expanding ( E) and contracting ( ) fluid volume chambers. The motor includes a shift valve spool ( ) to cause the motor to operate either in the normal, low-speed, high-torque (LSHT) mode (FIG. ) or in a high-speed, low-torque (HSLT) mode (FIG. ). When the motor operates in HSLT mode, certain of the volume chambers comprise recirculating volume chambers ( R). The motor ( ) defines a supplemental fluid passage ( ) through which fluid is communicated from a system charge pump ( ) to each of the recirculating volume chambers ( R). A control valve ( ) is operable, in a shift mode (S) to permit fluid communication from the charge pump ( ) to the supplemental fluid passage ( ), thus preventing cavitation during shifting of the motor ( ), especially when shifting from the HSLT mode to the LSHT mode.