Hydraulic emergency control for transmission ratio-dependent variation of the hydraulic oil pressure in the hydraulic conical pulley axial adjustment mechanisms of a continuously variable transmission

US5937729A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Ewald Spiess · Lambach, DE
• Hans Haecker · Leonberg, DE
• Joachim Luh · Bietigheim-Bissingen, DE
• Peter Baeuerle · Ludwigsburg, DE
• Rine Pelders · Nuland, NL
• Wilhelmus Johannes Maria Van Wijk · Udenhout, NL

Key dates

• Filing date: Nov 4, 1997
• Grant date: Aug 17, 1999
• Expiry date: Nov 4, 2017

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H2061/1268
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A hydraulic emergency control system for a continuous looped gear type continuously variable transmission (10) includes first and second hydraulic beveled conical pulley axial actuators controlling a gear ratio. A pump supplies a first piston chamber (13) of said first axial actuator via a sensor valve (20), wherein the sensor valve (20) is controlled by a flow control valve (73) connected downstream of the pump (80). The pump (80) supplies a second piston chamber (17) of the second axial actuator, with a pressure relief valve (40) limiting fluid pressure in said second piston chamber. Fluid in the second piston chamber (17) is controlled as a function of the fluid pressure in the first piston chamber (13) via a control line (52, 113).