Control system for automotive automatic transmission with emergency operation feature

US4233860A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Volker Kadelbach · Freiberg, DE
• Gerhard Will · Steinheim, DE
• Joseph Sauer · Strullendorf, DE

Key dates

• Filing date: Mar 6, 1978
• Grant date: Nov 18, 1980
• Expiry date: Mar 6, 1998

Classification

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

Abstract

To permit placing an electrical-hydraulical controlled automatic transmission, selectively, in reverse or neutral position upon failure of the control or command system, a spool valve is interposed between a fluid pressure pump and the control unit, the spool valve having three positions in which it can be placed manually; one of the positions is its normal operating position in which the valve provides a straight fluid path for pressurized fluid from the pump to the control unit; the other two positions are operable under emergency conditions, a second position providing a connection directly from the valve to the hydraulic servo units associated with control of the reverse gear, and the third interrupting suppply of hydraulic fluid from the pump to the control unit so that the control unit will, effectively, be placed in neutral position.