Vehicle wheel brake anti-lock system with low speed control

US4504911A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Volker Braschel · Neuwied, DE
• Wolf-Dieter Jonner · Freising, DE
• Heinz Leiber · Oberriexingen, DE

Key dates

• Filing date: Jun 18, 1982
• Grant date: Mar 12, 1985
• Expiry date: Jun 18, 2002

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B60T8/17616
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

To extend the range of automatic control of a brake anti-lock system, wheel speeds (V.sub.R1 -V.sub.R4) are processed and changed into control signals (12, 15) controlling braking effort of the vehicle. A first predetermined vehicle reference speed (V.sub.REF) is provided, and compared with a computed or actual vehicle speed. If the computed or actual vehicle speed drops below the first reference level (V.sub.REF1), a transfer switch (25) changes over control of the braking pressure control unit (22) from the standard control unit (23) to an auxiliary or additional branch (26) which initially maintains braking pressure, but drops braking pressure if the wheel speed of an individual wheel drops below a minimum level (V.sub.min) and the actual vehicle speed is above a second reference level (V.sub.REF2), which second reference level is below the first reference level (V.sub.REF1). The second reference level (V.sub.REF2) corresponds to a speed in excess of the minimum (V.sub.min).