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. 17, 1978
Filed:
Oct. 06, 1975
Toyota Jidosha Kogyo Kabushiki Kaisha, Toyota, JA;
Aisin Seiki Kabushiki Kaisha, Kariya, JA;
Abstract
A control system for a power dividing type hydraulic transmission in which the motive power supplied from an engine is transmitted mechanically. Part of the motive power is converted to hydraulic power by hydraulic pump motors to obtain infinitely variable speed ratios. The transmission includes a hydraulic pressure control system that operates by the use of electrically controlled solenoid valves. The control system detects the rotational speeds of an input and an output shaft, and when the speed ratio between the shafts is smaller than the mode converting speed ratio, a first solenoid valve is operated to engage a first clutch. When the speed ratio is greater than the mode converting speed ratio, a second solenoid valve is operated to engage a second clutch. The engagement of the clutches is timed so that both clutches are not coincidentally disengaged.