EP0327218A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Hydraulic anti-lock braking systems for vehicles
Assignee: ZF International UK Ltd
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Filing: 1989-01-18
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Granted: —
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Expires: 2009-01-18
Abstract
Abstract An hydraulic anti-lock braking system incorporates a pump (10) for generating the energy necessary to re-apply a brake (2) automatically after pressure applied to the brake from a master cylinder (1) has first been released to prevent the wheel (3) controlled by that brake from locking. The pump (10) is adapted to pump fluid back both to the brake (2) and to the master cylinder (1). Pumping the fluid back to the brake achieves a satisfactory pedal feel, and pumping fluid back to the master cylinder (1) ensures the use of a fail-safe re-application of brake pressure.
Inventors
- 👤 Glyn Phillip Reginald Farr
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 19:29
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/32; B60T8/34; B60T8/50; B60T8/5012; B60T8/42; B60T8/4275; B60T8/4283; B60T8/4291; B60T8/5006; B60T8/5018; B60T8/5025; B60T8/5037
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
109 words
An hydraulic anti-lock braking system for a vehicle in which the supply of hydraulic fluid from a master cylinder (1) to a brake (2) on a wheel (3) is modulated in an anti-lock mode in accordance with the behaviour of the braked wheel (3), and a pump (10) driven by a motor (11) is adapted to generate the energy necessary to re-apply the brake automatically after the pressure applied to the brake has first been released to prevent the wheel from locking, characterised in that the pump (10) is adapted to pump fluid back both to the brake (2) and to the master cylinder (1) during an anti-lock mode.
Claim 2
Dependent Claim
109 words
An hydraulic anti-lock braking system for a vehicle in which the supply of hydraulic fluid from a master cylinder (1) to a brake (2) on a wheel (3) is modulated in an anti-lock mode in accordance with the behaviour of the braked wheel (3), and a pump (10) driven by a motor (11) is adapted to generate the energy necessary to re-apply the brake automatically after the pressure applied to the brake has first been released to prevent the wheel from locking, characterised in that the pump (10) is adapted to pump fluid back both to the brake (2) and to the master cylinder (1) during an anti-lock mode.
Claim 3
Dependent Claim
35 words
A system according to claim 1, characterised in that substantially 70% of output from the pump (10) is returned to the brake (3), and the remaining substantially 30% is returned to the master cylinder (1).
Claim 4
Dependent Claim
107 words
A system according to claim 1 or claim 2, characterised in that the pump (10) comprises a plunger (17) working in a bore (18) in the housing (5) and movable in a first direction during an induction stroke to draw fluid into a pressure space (21) in the bore in front of the plunger (17) from an expansion chamber (12) and through a one-way inlet valve (22), the plunger (17) being movable in a second opposite direction during a power stroke to pump fluid from the pressure space (21) to the brake (3) and to the master cylinder (1) through respective first and second flow-control means (23,28;24).
Claim 5
Dependent Claim
55 words
A system according to claim 3, characterised in that the flow-control means (23,24) are so constructed and arranged such that a major portion of the output from the pump (10) is returned to the brake (3) during the delivery stroke of the pump and a relatively smaller portion is returned to the master cylinder (1).
Claim 6
Dependent Claim
23 words
A system according to claim 3 or claim 4, characterised in that the second flow-control means (24) comprises a second one-way outlet valve.
Claim 7
Dependent Claim
67 words
A system according to claim 5, characterised in that the first flow-control means (23) comprises a first one-way outlet valve, and one of the outlet valves (23,24) is rendered inoperative when the plunger (17) has moved through a first predetermined distance during the power stroke whereafter the output from the pump (10) during the reminder of the power stroke takes place through the other one-way valve (24,23).
Claim 8
Dependent Claim
82 words
A system according to claim 5 or claim 6, characterised in that the outlet valves (23,24) are arranged so that fluid is pumped to the brake (3) during movement of the plunger (17) through the first predetermined distance, with the output from the pump (10) during the remainder of the power stroke being pumped to the master cylinder (1) after an output port leading to the one-way valve (23) through which the brake is supplied has been masked by the plunger (17).
Claim 9
Dependent Claim
50 words
A system according to claim 3 or claim 4, characterised in that the first flow-control valve (28) comprises a restricted orifice, and the orifice (28) is so positioned, constructed, and arranged that it achieves a build up of back pressure capable of causing the second one-way valve to open (24).
Claim 10
Independent Claim
101 words
A system according to any preceding claims, characterised in that a first normally-open control valve (6) is located between the master cylinder (1) and the brake (2), and a second normally-closed control valve (8) is located between the brake (2) and the expansion chamber (12), both control valves being responsive to an anti-lock signal whereby the first valve to caused to close and isolate the master cylinder from the brake, the second valve is caused to open to release fluid from the brake to the expansion chamber, and the motor (11) is operated to cause the pump plunger (17) to oscillate.
Claim 11
Dependent Claim
17 words
A system according to claim 9, characterised in that each control valve (6,8) comprises a solenoid-operated valve.
Claim 12
Dependent Claim
28 words
A system according to claim 9, characterised in that the first control valve comprises a flow-control valve (40) and the second control valve (8) comprises a solenoid-operated valve.
References Cited (Backward Citations)
No citation records indexed.
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