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:
May. 01, 1990
Filed:
Aug. 10, 1984
Mannesmann Rexroth GmbH, Lahr, DE;
Abstract
The torque of a hydraulic machine is dependent of the fluid pressure delivered to the machine and is further dependent of the adjustment of its volume of through-put. In response to a load coupled to the machine, a speed results which is controlled by a speed control system acting on the adjusting system of the hydraulic machine. According to the invention, an electro hydraulic speed control comprises a pair of control circuits which are connected to, but operate independent of each other. Thus the electrical control circuit produces a control signal y.sub.e1 from the difference of the actual value and the desired value of the speed for adjusting a hydraulic restricting means which produces a hydraulic pressure signal p.sub.st in the hydraulic control circuit which pressure signal is compared with a hydraulic reference signal p.sub.o to produce a differential pressure signal p.sub.o -p.sub.st which is applied to the adjusting cylinder of the hydraulic machine. The control system thus comprises two circuits, i.e. an electrical speed control circuit and a hydraulic pressure control circuit resulting in optimizing the control operation.