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:
Jun. 28, 1977
Filed:
Feb. 27, 1976
Alan Leonard Miller, Mount Prospect, IL (US);
John Saxon Ivey, Bloomfield Hills, MI (US);
Borg-Warner Corporation, Chicago, IL (US);
Abstract
A control system used to change the gear ratio in a gear set regulated by a change-gear signal from a control unit is disclosed. A transducer provides an output torque signal which is compared to other signals for initiating the gear change. In another arrangement, an automatic transmission changes a gear ratio when engine torque is transferred from one member to another member of a three member planetary gear set. This transfer is accomplished through friction elements engaged by hydraulic pressure. A closed loop electrical circuit is completed between a transducer, which provides an electrical signal related to the output torque of the transmission, and a control valve, to vary the control valve pressure. A circuit for computing reaction torque is coupled between the transducer and a logic control circuit, which provides logic command signals for controlling operation of components in the closed loop circuit. The closed loop circuit includes a pulse width modulation circuit for regulating the control valve operation, and a feed-forward circuit to minimize the delay in the control valve portion of the system.