Brake lining wear sensing system
AssigneeLucas Industries public limited company
InventorsMalcolm Brearley, Andrew John Ward, Dennis John McCann, Paul Antony Fawkes
Life of this patent
Estimating the term…
Abstract
A wear sensing system for the brake linings of a vehicle. Since the sensors are mounted within the brake mechanism, the reduction in the disc thickness must be taken into account to supply an accurate reading. A non-volatile memory stores the position of the brake before replacement and is compared to the position after replacement. However, the latter reading is established only after a predetermined number of brake applications to take up any starting clearances.
Claims29
A lining wear measurement system, operating from a displacement sensor coupled to a moving element within a vehicle brake, the system having a microprocessor controller, a system memory adapted to hold internally in said system memory a starting point and a target wear-out point representing a minimum acceptable brake lining thickness based upon the characteristics of known linings, which comprises:
- (a) a first device which recognizes an opening operation of the brake, such as is necessary to remove worn linings for inspection and replacement purposes, by comparison of pre-opening and post-opening brake position readings which are taken from either measurements or measurement averages, which are stored in said system memory, at least said pre-opening reading being stored in non-volatile memory so as not to lose data when system power is turned off;
- (b) a second device located within the microprocessor controller for establishing that the brake has been equipped with a new unused seat of linings;
- (c) a third device effective after a determination has been made by said first device that the brake has been equipped with a set of new unused linings, to generate and automatically set into the memory a new reference datum for wear measurements;
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- (d) a fourth device effective to generate and set into the memory a target wear-out point, representing a minimum acceptable brake lining thickness, obtained by subtracting from said new references datum the known thickness of new unused linings, thereby enabling the target wear-out point to take into account the reducing disc or drum thickness as the life of the brake progresses.
A lining wear measurement system, operating from a displacement sensor coupled to a moving element within a vehicle brake, the system having a microprocessor controller, a system memory adapted to hold internally in said memory a starting point and a target wear-out point representing a minimum acceptable brake lining thickness based upon the characteristics of known linings, which comprises:
- (a) first device for recognizing an opening operation of the brake, such as is necessary to remove worn linings for inspection and replacement purposes, by comparison of pre-opening and post-opening brake position readings which are taken from either measurements or measurement averages, which are stored in said system memory, at least said pre-opening reading being stored in non-volatile memory so as not to lose data when system power is turned off;
- (b) a second device for establishing that the brake has been equipped with a new unused set of linings;
- (c) a third device effective after a determination has been made that the brake has been equipped with a set of new unused linings, to manually initiate the generating and setting into the memory of a new reference datum for wear measurements;
- and
- (d) a fourth device effective for generating and setting into the memory a target wear-out point, representing a minimum acceptable brake lining thickness, obtained by subtracting from said new reference datum the known thickness of new unused linings, thereby enabling the target wear-out point to take into account the reducing disc or drum thickness as the life of the brake progresses.
Dependencies are inferred from the claim text.