Device for controlling the gear ratio of a continuously variable transmission

US5947862A · kind A · utility

Assignee

• ZF FRIEDRICHSHAFEN AG · DE

Inventors

• Thomas Knapp · Kent, US
• Gerhard Eschrich · Tettnang, DE
• Wolfgang Runge · Ravensburg, DE

Key dates

• Filing date: Dec 17, 1997
• Grant date: Sep 7, 1999
• Expiry date: Dec 17, 2017

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B60W2050/0042
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A device for controlling the gear ratio of a continuously variable transmission. The theoretical rotational speed or transmission ratio is fed to the signal input of a set-value filter (44). The time constant (T.sub.-- RS) of the set-value filter (44) is adaptively controlled so that the change in transmission ratio takes place in accordance with a transition function whose limit is defined by a maximum variation speed. The principal advantage of the invention is that the vehicle is not slowed when shifting down to lower transmission ratios.