EP0609361A1 - Systeme de frein electohydraulique - Google Patents
Systeme de frein electohydrauliqueInfo
- Publication number
- EP0609361A1 EP0609361A1 EP92922711A EP92922711A EP0609361A1 EP 0609361 A1 EP0609361 A1 EP 0609361A1 EP 92922711 A EP92922711 A EP 92922711A EP 92922711 A EP92922711 A EP 92922711A EP 0609361 A1 EP0609361 A1 EP 0609361A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pressure
- pump
- master cylinder
- piston
- brake
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/58—Combined or convertible systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/66—Electrical control in fluid-pressure brake systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
- B60T13/745—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive acting on a hydraulic system, e.g. a master cylinder
Definitions
- the present invention relates to an electro- hydraulic braking system in which the primary braking force is supplied to brake cylinders by a pump moved by an electric motor.
- FIGURE 1 A simplified version of an electro-hydraulic braking system is shown in FIGURE 1.
- the system comprises a pump 12 powered by a motor 14 in response to control signals generated by an electronic control unit (ECU) 16.
- ECU electronice control unit
- the pump directly pressurizes a brake cylinder or cylinders generally shown as 18.
- the speed of the motor 14/pump 12 is controlled so as to modulate brake system pressure in accordance with a commanded brake pressure signal.
- a by-pass orifice 20 is provided across the pump 12 which enhances the stability of motor/pump speed and allows for the rapid release of brake cylinder pressure when required.
- FIGURE 2 illustrates an improvement to the simplified system shown in FIGURE 1 in which a master cylinder 22 has been added to provide brake system redundancy in the event that the pump 12 or electronics fail.
- the motor control signal is generated by comparing master cylinder pressure as generated by a pressure sensor 24, to a signal indicative of the pressure in the brake cylinder 18 as determined by pressure sensor 26.
- An isolation valve 28 is used to communicate either the master cylinder or the output of the pump to one or more brake cylinders 18.
- the isolation valve may be a pressure piloted isolation valve responsive to pump output pressure.
- the system illustrated utilizes, in a general sense, a flow control device 20 across the pump. This- flow control device may be implemented in many different ways, including the fixed orifice shown in FIGURE 1 or the solenoid valve shown in FIGURE 2.
- an electro-hydraulic brake system comprising: a master cylinder; a pump the output communicated to a pressure regulating valve means; a motor for rotating the pump at a determinable speed; isolation valve means selectively connecting one of the master cylinder and pump to a brake cylinder or group of brake cylinders and first means for generating a signal indicative of operator initiated brake activity to cause activation of the pump.
- the valve means is connected between the master cylinder and pump and regulates the output pressure of the pump at a determinable level in proportion to the pressure generated by the master cylinder and for providing a path to drain the brake cylinder(s) to a reservoir during intervals of decreasing master cylinder pressure.
- the system may also include an excess flow valve(s) which will prevent the reservoir from being drained by the pump in the event of a malfunction such as a defective or leaky brake cylinder or a hole (leak) in a hydraulic line.
- an excess flow valve(s) which will prevent the reservoir from being drained by the pump in the event of a malfunction such as a defective or leaky brake cylinder or a hole (leak) in a hydraulic line.
- Various embodiments of the valve means are described which add additional failure mode protection to the system.
- FIGURES 1 and 2 illustrates simplified versions of an electro-hydraulic braking system.
- FIGURE 3 illustrates an improved electro- hydraulic system incorporating features of the present invention.
- FIGURE 4 illustrates an alternate embodiment of a pressure regulating valve.
- FIGURE 5 illustrates another brake system.
- FIGURE 6 illustrates another embodiment of a valve. DETAILED DESCRIPTION OF THE DRAWINGS
- FIGURE 3 schematically illustrates an electro-hydraulic brake system 30.
- the system includes a master cylinder 32 and a pump 34 such as a positive-displacement pump rotated by a motor 36.
- the motor 36 is activated through a relay 38 by a control signal generated by an ECU 40.
- the output signal from a brake light switch 80 (or similar command) is used to activate the relay 38. While an ECU 40 is shown, this could be eliminated.
- the ECU 40 may in its simplest form include electronic filters and a buffer or amplifier circuit for powering the relay 38.
- the output of the pump 34 and the output of the master cylinder 32 are communicated to an isolation valve generally shown as 42 similar in function to the isolation valve 28 of FIGURE 2.
- the system 30 further includes a pressure regulator which is also referred to as valve 50.
- valve 50 regulates pump pressure i.e., the pressure supplied to the brake cylinder(s) at a determinable ratio of master cylinder pressure.
- FIGURE 3 shows one embodiment of the valve 50 which comprises a first piston 52 exposed to master cylinder pressure, movable within a piston passage 56.
- the piston includes a pin or closure element 54.
- One end 60 of the piston passage 56 is communicated to the pump 34 as well as to the brake cylinder or cylinders 44.
- the piston passage 56 includes a by-pass passage 58 communicated to a reservoir 62.
- a first orifice 70 is provided in the piston passage 56 and defines a flow area A__ which is equal to or less than the area A 2 of the first piston 52 that is exposed to master cylinder pressure. As can be seen, the first orifice 70 is located between the by-pass passage 58 and the end 60 of the piston passage 56.
- the system 30 additionally includes a means for generating a signal indicative of operator initiated brake activity.
- a means for generating a signal indicative of operator initiated brake activity As illustrated in FIGURE 3, and as mentioned above, an indication that the operator has stepped on the brake pedal 82 is sensed by the closure of a brake light switch generally shown as 80.
- the brake light switch is communicated to the ECU 40 which in turn activates relay 38 to cause the motor 36 to rotate at a relatively constant speed defined by the pump pressure needed to create a force balance across the first piston 52.
- an indication of braking activity can be generated by utilizing a force sensor 84 to measure brake pedal force or a pressure sensor 86 to measure developed master cylinder pressure.
- brake light switch 80 As opposed to a force transducer 84 or pressure sensor 86 is that the brake light switch 80 will generate a signal slightly before a force sensor or pressure sensor will generate its corresponding signal. Using the brake light switch as a measure of brake activity reduces time delays permitting a more rapid energization of the motor 36/pump 34.
- a 2 is greater than x a boosted pump pressure is generated analogous to the output of a conventional power brake.
- the pressure regulating action of the valve 50 works on a force balance principle.
- the master cylinder pressure acts on the working area of its associated piston (piston 52) and produces a force which is balanced by the pump 34 acting on an associated element (pin or element 54) .
- the pin 54/piston 52 will move until sufficient flow passes through the orifice 70 to produce the required pressure difference.
- FIGURE 3 illustrates a separate master cylinder and valve 50, it should be appreciated that the valve 50 can be incorporated within a modified master cylinder.
- FIGURE 3 shows a single brake channel.
- FIGURE 5 shows a plurality of excess flow valves and a two channel brake system from which the benefit of these valves is more readily apparent.
- FIGURE 4 illustrates an alternate valve 50'.
- FIGURE 5 illustrates an exemplary braking system 30' for the control of four brake cylinders 44.
- the valve 50' also shown schematically in FIGURE 5, is functionally analogous in operation to valve 50.
- An added feature is that this valve 50' is adapted to communicate to a master cylinder having primary and secondary master cylinder chambers 32a and 32b, respectively providing failure redundancy in operation.
- the valve 50' includes a housing 100 defining a plurality of ports 102, 104, 106 and 108, adapted to respectively communicate to the primary master cylinder chamber 32a, pump 34, reservoir 62 and the secondary master cylinder chamber 32b.
- the valve 50' includes the first piston 52 (see FIGURE 4) and closure element 54 and a valve seat 110 defining the orifice 70.
- Port 104 illustrates the use of an inverted SAE fitting which may also be used in any of the various ports of the valve 50' .
- the piston 52 is slidably received within a bore 114 which also supports a second piston 116.
- the valve 50' includes an-additional two ports 120a and 120b which communicate to the isolation valves 42a and 42b shown in FIGURE 5.
- the exemplary system of FIGURE 5 shows a cross-split brake configuration in which the primary master cylinder 32a is communicated to the left front and to the right rear brake cylinders 44 through a proportioning valve 122a.
- Secondary master cylinder pressure is used to control the right front and left rear brake cylinders through a second proportioning valve 122b.
- the passage 114 between the connection points of the primary and secondary master cylinder, is also communicated to the exhaust port through a passage 126.
- This passage 126 provides a region of atmospheric pressure about piston 116.
- the purpose of this vent or passage 126 is to insure that if any of the regulator seals such as 128 fail, this failure will be detectable. As an example, if one of the seals 128 fail the secondary master cylinder chamber pressure will decrease as brake fluid will flow to the reservoir. This low pressure will be detected by a low pressure switch in the secondary master cylinder chamber. The pressure switch will typically activate a light on the dashboard informing the driver of the failure.
- valve 50' is operable in the event of a failure of one or the other master cylinder chambers or in the hydraulic lines connecting these chambers to the valve 50'.
- valve 50' The operation of the valve 50' is as follows. As is typically the case, the pressure generated in the primary master cylinder will be approximately 20 to 50 psi (1.38-3.45 bar) greater than the pressure generated in the secondary master cylinder. With the system connected as shown in FIGURE 5, the primary master cylinder pressure is received into chamber 130 of FIGURE 4. This pressure force urges piston 52 downwardly and piston 116 upwardly against stop 132. As can be appreciated, the dynamics of valve 50', in this condition, are essentially identical to those of valve 50. In this operating condition, secondary master cylinder pressure does not play an operative role in regulating the output pressure of the pump. The valve 50' will continue to operate even in the face of a failure of the hydraulic system upstream of port 108 i.e. the secondary master cylinder chamber.
- FIGURE 6 illustrates an alternate embodiment of a pressure regulating valve 50".
- the valve 50" includes a housing 104 into which are received three pistons 206, 208 and 212.
- a pin 214 is secured to one of the pistons 206 or 208.
- the pin 214 is secured to piston 208 and is slidably received within a bore 216 of piston 206.
- Pistons 206 and 208 are slidably received within a central bore 220.
- Piston 212 is received within another bore 222.
- Various dynamic seals such as 224 and 226 are provided to prevent leakage through the various bores 220 and 222.
- seal 224 can be a GLYD ring while seal 226 is shown as an O-ring.
- Piston 212 supports a valve closure element 230 which is spherically shaped and adapted to seat upon a valve seat 232 defining an orifice 234.
- the valve 50" includes a plurality of ports 104, 106, 102 and 108 respectively connected to the pump 34, the reservoir 62, the primary master cylinder chamber 32a, and the secondary master cylinder chamber 32b.
- the valve 50" also includes a plurality of vents schematically shown as 242 and 246. As can be appreciated exterior vents are not necessary. Alternately, the bores 220 and 222 can be vented to atmosphere through internal passages
- the piston 208 has a first working surface 260 of area A 3 which is exposed to primary master cylinder pressure.
- the piston 212 has a second working surface 262 of area A ⁇ which is also exposed to atmosphere through the vent 246.
- the operation of the system 200 is as follows. Fluid from the primary chamber 32a will fill the chamber 250 between pistons 206 and 208 and act on the first working surface 260 of piston 208 causing the piston 208 to press down on the working surface 262 of piston 212 causing element 230 to fully close orifice 234. This action enables the full output of the pump 34 to be communicated to the brake cylinder 44. As the pump pressure builds, it acts upon the piston 212 to move away from the valve seat 232 in opposition to the forces exerted on piston 208. As the piston 212 moves out from the orifice 234, the output of the pump 34 will be regulated to a determinable pressure which is a function of master cylinder pressure and more specifically a function of the primary master cylinder pressure. It can be shown that this determinable pressure equals:
- P [(A 3 /(A 2 -A X )] x P pmc
- P pmc is primary master cylinder pressure
- a 3 is the area across piston 208
- a 2 the area of the piston 212
- a 1 is the area of the orifice 234.
- the valve 50" shown in FIGURE 6 will permit the pressure generated by the pump to be greater than the pressure generated by the primary master cylinder pressure. If it is desired that the pump pressure be more closely related to master cylinder pressure, that is, that the relationship between pump pressure and primary master cylinder pressure approach unity, then the cross-sectional areas of the various pistons will be made equal.
- valve 50" includes failure mode protection similar to that employed in valve 50' and will continue to operate even if primary or secondary master cylinder pressure is not communicated to the various ports.
- the output pressure of the pump 34 will be regulated as a function of the secondary master cylinder.
- the relationship is as follows: where P ⁇ mc is secondary master cylinder pressure and A 4 is the area of the piston 206 exposed to secondary master cylinder pressure.
Landscapes
- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Valves And Accessory Devices For Braking Systems (AREA)
- Braking Systems And Boosters (AREA)
- Regulating Braking Force (AREA)
Abstract
Système de frein électrohydraulique (30) comprenant: un maître-cylindre (32), une pompe (34) dont le débit est transmis à une soupape (50) de régulation de pression, un moteur (36) destiné à mettre en rotation la pompe, une soupape d'isolation (42) destinée à raccorder sélectivement le maître-cylindre et/ou la pompe à un ou des cylindres de frein (44), ainsi qu'un générateur de signal (40) destiné à activer la pompe. Une soupape de régulation de pression est reliée entre le maître-cylindre et la pompe afin de réguler la pression de débit de la pompe à un niveau déterminable proportionnel à la pression générée par le maître-cylindre, et pour ménager un chemin permettant de vider le ou les cylindres de frein dans un réservoir au cours d'intervalles de diminution de la pression du maître-cylindre. Le système peut également comprendre une ou des soupapes (90) de débit excédentaire destinée(s) à empêcher que le réservoir ne soit vidé par la pompe dans le cas d'un mauvais fonctionnement du système. Divers modes de réalisation de la soupape de régulation prévoient une protection supplémentaire à mode de panne.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US78585091A | 1991-10-31 | 1991-10-31 | |
US785850 | 1991-10-31 | ||
PCT/US1992/008922 WO1993009012A1 (fr) | 1991-10-31 | 1992-10-19 | Systeme de frein electohydraulique |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0609361A1 true EP0609361A1 (fr) | 1994-08-10 |
Family
ID=25136816
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP92922711A Withdrawn EP0609361A1 (fr) | 1991-10-31 | 1992-10-19 | Systeme de frein electohydraulique |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0609361A1 (fr) |
JP (1) | JPH07500550A (fr) |
CA (1) | CA2120596A1 (fr) |
MX (1) | MX9206198A (fr) |
WO (1) | WO1993009012A1 (fr) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5776963A (en) * | 1989-05-19 | 1998-07-07 | Hoechst Marion Roussel, Inc. | 3-(heteroaryl)-1- (2,3-dihydro-1h-isoindol-2-yl)alkyl!pyrrolidines and 3-(heteroaryl)-1- (2,3-dihydro-1h-indol-1-yl)alkyl!pyrrolidines and related compounds and their therapeutic untility |
US5364866A (en) | 1989-05-19 | 1994-11-15 | Hoechst-Roussel Pharmaceuticals, Inc. | Heteroarylpiperidines, pyrrolidines and piperazines and their use as antipsychotics and analetics |
FR2719678B1 (fr) * | 1994-05-06 | 1996-09-06 | Alliedsignal Europ Services | Système de régulation de pression à structure hybride pour un circuit hydraulique de freinage de véhicule automobile. |
US5855417A (en) * | 1994-09-12 | 1999-01-05 | General Motors Corporation | Integral control and isolation valve proportional brake system |
WO1996026091A1 (fr) * | 1995-02-22 | 1996-08-29 | Bosch Braking Systems Corporation | Systeme de freins de stationnement hydraulique et electrique |
ES2122919B1 (es) * | 1996-11-19 | 1999-07-16 | Gonzalez Mena Francisco | Sistema de activacion del servofreno en vehiculos automoviles. |
JPH1148955A (ja) * | 1997-08-08 | 1999-02-23 | Toyota Motor Corp | 液圧ブレーキ装置 |
DE19949816A1 (de) * | 1999-10-15 | 2001-04-19 | Bosch Gmbh Robert | Betätigungseinheit für eine Radbremse eines Kraftfahrzeugs |
DE102008021840B3 (de) * | 2008-04-11 | 2009-06-25 | Knorr-Bremse Systeme für Nutzfahrzeuge GmbH | Verfahren und Vorrichtung zum Regeln eines Druckes eines EBS-Bremssystems beim Ausfall eines Regelkreises |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3424912A1 (de) * | 1984-07-06 | 1986-01-16 | Alfred Teves Gmbh, 6000 Frankfurt | Elektronisch kontrolliertes bremsbetaetigungssystem |
JP2590825B2 (ja) * | 1986-07-12 | 1997-03-12 | トヨタ自動車株式会社 | マニユアル・電気二系統ブレーキ装置 |
FR2620097B1 (fr) * | 1987-09-04 | 1992-02-21 | Renault | Dispositif generateur de pression pour circuits de freinage de vehicules automobiles |
-
1992
- 1992-10-19 JP JP5508451A patent/JPH07500550A/ja active Pending
- 1992-10-19 CA CA 2120596 patent/CA2120596A1/fr not_active Abandoned
- 1992-10-19 EP EP92922711A patent/EP0609361A1/fr not_active Withdrawn
- 1992-10-19 WO PCT/US1992/008922 patent/WO1993009012A1/fr not_active Application Discontinuation
- 1992-10-28 MX MX9206198A patent/MX9206198A/es unknown
Non-Patent Citations (1)
Title |
---|
See references of WO9309012A1 * |
Also Published As
Publication number | Publication date |
---|---|
CA2120596A1 (fr) | 1993-05-13 |
WO1993009012A1 (fr) | 1993-05-13 |
JPH07500550A (ja) | 1995-01-19 |
MX9206198A (es) | 1993-07-01 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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17P | Request for examination filed |
Effective date: 19940322 |
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AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB IT |
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RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: ALLIEDSIGNAL INC. |
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17Q | First examination report despatched |
Effective date: 19940920 |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 19950527 |