EP0197803A1 - Hydraulic assistance device - Google Patents
Hydraulic assistance device Download PDFInfo
- Publication number
- EP0197803A1 EP0197803A1 EP19860400303 EP86400303A EP0197803A1 EP 0197803 A1 EP0197803 A1 EP 0197803A1 EP 19860400303 EP19860400303 EP 19860400303 EP 86400303 A EP86400303 A EP 86400303A EP 0197803 A1 EP0197803 A1 EP 0197803A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- piston
- chamber
- pressure
- piston means
- valve
- 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.)
- Granted
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
-
- 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
- B60T13/12—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 the fluid being liquid
- B60T13/14—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 the fluid being liquid using accumulators or reservoirs fed by pumps
- B60T13/141—Systems with distributor valve
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T137/00—Fluid handling
- Y10T137/8593—Systems
- Y10T137/87169—Supply and exhaust
- Y10T137/87193—Pilot-actuated
Definitions
- the present invention relates to a hydraulic assistance device and more particularly to such a device for a dual braking circuit with mixed hydrodynamic (known as "full power") and hydrostatic operation.
- a hydraulic assistance device for a dual braking circuit is described in French Patent Application 84-01439 and is of the "full power" type which is capable of operating as a conventional master cylinder, in a hydrostatic mode, in the case of failure of the high pressure supply circuit.
- This device comprises two pistons which are slideably mounted in a common bore and which are each associated with a respective braking circuit.
- One piston is moveable by a brake pedal and a hydrostatic connection between the two pistons causes movement of the second piston.
- Each piston comprises a valve means which, when the device is operated, puts a respective source of high pressure fluid into communication with the brakes of the vehicle.
- the brake pedal acts upon a piston which is slideably mounted in the bore and this piston is connected to the first piston means by a spring to provide pedal feel.
- a valve between a chamber, defined between the piston and the first piston, and low pressure reservoir may close undesiderably and form a direct hydrostatic connection between the piston and the first piston.
- the result of this connection is that the pedal feel is reduced, and in addition the opening of the first valve means become too abrupt.
- the object of the invention is therefore to provide an improved hydraulic assistance device for a dual circuit of the type known as "full power" which is capable of operating as a conventional master cylinder in the event of failure of the high pressure circuit and in which the feature of pedal feel is assured.
- a hydraulic assistance device comprising a body comprising a bore in which a first piston means and a second piston means are slideably mounted, the first piston means being movable under the effect of the actuation of third piston slideably mounted in the body, and the second piston means being movable by the intermediary of a hydraulic connection formed in a pressure chamber defined between the first and the second piston means, a respective valve means being associated with each piston means in a respective hydraulic circuit between a source of fluid under pressure and a respective braking circuit ; and a third chamber defined in the bore between the first piston means and the third piston, the said third chamber being connected to a low pressure reservoir through a passage in which a valve means is mounted, characterized in that the device incorporates a second valve means in a second passage between the third chamber and the reservoir, the second valve means being responsive to the pressure of the corresponding source of pressure so that, upon failure of this high pressure source, the second valve means closes so as to isolate the third chamber from the reservoir.
- the first piston means further comprises a control piston on which is fixedly mounted a ball adapted to close a valve seat in the first piston means to thereby close the fluid passage between the first pressure chamber and the third chamber.
- the hydraulic assistance device which in the example shown is a master cylinder for a braking circuit, comprises a body 10 including a single bore 12 which is closed at one end by a closure component 14.
- a first piston 16 is slideably mounted in the bore 12 and is intended to be connected to a brake pedal of a vehicle (not shown).
- a first piston means and a second piston means 18, 20 are slideably mounted in the bore 12 defining between them a first pressure chamber 22.
- a second pressure chamber 24 is defined between the second piston means 22 and the closure component 14.
- the first piston means 18 comprises a control piston 26 which includes, in an internal bore 27 connecting the first chamber 22 to a low pressure reservoir 25 (not shown), a ball 28 which is pushed to the right, (when viewing the drawings), by a spring 30.
- a control component 32 is slideably mounted in bore 27 and has at its end a seat 34, which is capable of being closed by the ball 30 and connected to a chamber 36 in the bore 12 by an internal passage 38.
- the control component 32 is connected to the first piston 16 by a spring 40 and comprises an annular seal 42 which is capable of closing the passage between the passage 38 and the chamber 40 by coming into abutment against an annular shoulder 44, at the rear of the control piston 26.
- the first piston means 18 defines with the bore 12 an annular space 46 which is bounded axially by two annular cups 48, 50 and is connected to a source of high pressure hydraulic fluid 52 by a passage 54 in the body 10.
- the first piston means 18 also includes a bore 56 which is in hydraulic communication with the annular space 46 by way of a lateral opening 58 and which includes a ball 60 which is normally pushed towards a seat 62 by a spring 64.
- the control piston 26 comprises a rod 66 which, when the control piston moves to the left, lifts the ball 60 from its seat 62 and allows fluid to pass under pressure from the source 52 through a passage 68, the first pressure chamber 22 and two outlets 70, 72 towards the brakes of a primary braking circuit 74.
- the second piston means 20 comprises a stepped bore 76 in which a control piston 78 is slideably mounted in a sealed manner, and which includes a stepped bore 80 and a lateral opening 82 which together join the second chamber 24 to the reservoir 25.
- a ball 84 is mounted in the bore 76, the ball 84 being retained by a piston component 86 and normally pushed to the right by a spring 88 so as to open a seat 90 formed in the bore 80 of the control piston 78.
- a spring 92 connects the first and second piston means 18, 20.
- the closure component 14 includes a stepped bore 94 which is connected to a high pressure source of fluid 96 and which comprises a first valve means 98 and a ball valve 100 which is normally pushed towards its closed position by a spring 102.
- the control piston 78 comprises a rod 104 which, when the control piston moves to the left, opens the ball valve 100 and allows the fluid under pressure to pass through the second chamber 24 and two ports 106, 108 towards the brakes of a secondary braking circuit 110.
- the hydraulic assistance device also includes in the body 10 a valve means generally indicated by reference 112.
- the valve means 112 comprises a stepped bore 114 in which a valve 116 is slideably mounted and which includes two annular cups 118, 120 and a spring 122 which normally pushes the valve to the left, (when viewing the drawings).
- One end 124 of the bore 114 is connected by way of a passage 126 and the annular space 46 to the high pressure source 52.
- the other end 128 of the bore 114 is connected to the chamber 40 through a passage 130.
- a third passage 132 connects the central portion 134 of the bore 114 to the low pressure reservoir 25.
- valve 116 moves to the left, the cup 120 comes into contact with an annular wall 136 of the stepped bore 114 and isolates the chamber 40 from the reservoir 25.
- the high pressure source 52 is isolated from the reservoir 25 and from the chamber 36 by the cup 118, the high pressure of this source simply pushing the valve 116 to the right against the force of the spring 122.
- the device described above operates as follows. A force applied by the brake pedal onto the piston 16 is transmitted by the spring 40 to the control component 42 which moves to the left, and closes the ball valve 28. The control piston 26 then moves relative to the first piston means 18 and opens the ball 60 by way of the rod 66. Opening the ball 60 allows fluid under pressure to pass from the source 52 through the opening 58, the passage 68, the first pressure chamber 22 and the ports 70, 72, towards the brakes 74. The rise in pressure of the primary circuit causes the retraction of the control piston 26 which is in equilibrium with the pedal feel spring 40.
- the rise in pressure in the pressure chamber 22 also results in movement of the second piston means 20 and thus closure of the ball valve 84 and movement of the second control piston 78 to the left
- This movement of the control piston 78 opens the ball 100 by way of the rod 104. Opening the ball 100 allows fluid under pressure to pass from the source 96 to the brakes 110 through the second pressure chamber 24 in which the fluid pressure will rise until equilibrium is obtained between the pressures of the primary circuit 74 and the secondary circuit 110.
- the two circuits are resup- plied by the reopening of the two ball valves 28 and 84.
- valve means 112 In normal operation, the valve means 112 remains in its open position as shown, the force of the high pressure fluid being greater than that of the spring 122.
- the chamber 40 is thus in hydraulic communication with the reservoir 25 and suitable pedal feel is provided by the spring 40.
- the annular cup 42 which normally remains open during operation of the device, closes, the rise in pressure of the primary braking circuit 74 being insufficiently rapid to create a reaction force on the control component 38.
- the valve means 12 remains open allowing fluid to pass from the chamber 36 to the reservoir 25 and the spring for pedal feel remains operative.
- Another advantage of the present invention compared with the prior art lies in the fact that the piloting of the secondary circuit 110 occurs over the whole of the transverse section of the second piston means 20, which, when the device is operated reduces the effect of friction of the seals of this second piston means and the effect of sudden opening of the ball valve 100 of the secondary circuit.
- FIG. 2 A second embodiment of the invention is shown in Figure 2 in which components common to the embodiment of Figure have the same reference numerals.
- the previous embodiment has a relatively large number of components resulting in increased manufacturing costs.
- the following embodiment was designed with a view to reducing both the number of components and the size of the device.
- the first piston means 18 is simplified with respect to that of the embodiment of Figure 1 and comprises a control component 232 slideably mounted in a stepped bore 200.
- the control component 232 is connected to the first piston 16 by spring 40.
- the first piston means 18 further comprises a control piston 226 slideably mounted in stepped bore 200 and receiving, in its end adjacent the control component 232, a ball 228 adapted to close against a valve seat 202 in the control component 232 and thus close the fluid passage between the first pressure chamber 22 and chamber 36.
- Chamber 36 communicates with the low pressure reservoir 25 by way of a passage 130, a valve means 112 and a passage 130'.
- a second return passage to the low pressure reservoir 25 is provided by way of an opening 234, a tilting valve 236 and a passage 238.
- the second piston means 20 is also simplified with respect to that of the previous embodiment.
- a control piston 78 is slideably mounted in the second piston means 20 by way of an annular component 204 which is mounted in an end of the second piston means 20.
- a ball 284 which is adapted to close against a valve seat 290 in the second piston means 20 to thus close the fluid passage between the second pressure chamber 24 and the low pressure reservoir 25.
- the other end of the control piston 78 is slideably received in a sleeve 206 which also receives, at its other end, an actuator element 208 which, when the device is operated, opens ball valve 210 to allow fluid under pressure to flow from the high pressure source 96 to the vehicle's secondary braking circuit 110.
- the small diameter of ball 284 and the fact that it is mounted on the control piston 78 results in a reduction of the size of the device and its number of components.
- control piston 78 and sleeve 206 results in the simplification of the structure of closure component 14 while allowing sufficient travel for the second piston means in the event of a high pressure circuit failure whereupon the device operates as a conventional master cylinder in a hydrostatic mode.
- the device operates in a similar way to that of the first embodiment, apart from the following differences.
- the ball valve 228 remains open while valve means 112 closes under the effect of spring 122.
- Tilting valve 236 closes when the first piston means 18 moves away from its illustrated rest position.
- the first piston 16 becomes the piston of a conventional, hydrostatic master cylinder and fluid passes from chamber 36 via valve seat 202 and opening 58 to the primary braking circuit 74.
- This method of operation results in a reduction of brake pedal dead stroke.
- valve means 112 remains closed and chamber 22 is replenished by way of tilting valve 236.
- the tilting valve 236 is opened as a result of the pressure differential across it .
- the first piston means abuts an extension 240 of tilting valve 236 and thus holds it in its open position.
- the modified construction of the second embodiment results in a more compact assembly and a reduction in the number of components while ensuring optimum operation in both the hydrodynamic and hydrostatic modes.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Transportation (AREA)
- Fluid Mechanics (AREA)
- Analytical Chemistry (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Braking Systems And Boosters (AREA)
- Transmission Of Braking Force In Braking Systems (AREA)
- Fluid-Pressure Circuits (AREA)
- Valves And Accessory Devices For Braking Systems (AREA)
- Actuator (AREA)
Abstract
Description
- The present invention relates to a hydraulic assistance device and more particularly to such a device for a dual braking circuit with mixed hydrodynamic (known as "full power") and hydrostatic operation.
- A hydraulic assistance device for a dual braking circuit is described in French Patent Application 84-01439 and is of the "full power" type which is capable of operating as a conventional master cylinder, in a hydrostatic mode, in the case of failure of the high pressure supply circuit. This device comprises two pistons which are slideably mounted in a common bore and which are each associated with a respective braking circuit. One piston is moveable by a brake pedal and a hydrostatic connection between the two pistons causes movement of the second piston. Each piston comprises a valve means which, when the device is operated, puts a respective source of high pressure fluid into communication with the brakes of the vehicle. The brake pedal acts upon a piston which is slideably mounted in the bore and this piston is connected to the first piston means by a spring to provide pedal feel. In the case of rapid braking it is possible that a valve between a chamber, defined between the piston and the first piston, and low pressure reservoir may close undesiderably and form a direct hydrostatic connection between the piston and the first piston. The result of this connection is that the pedal feel is reduced, and in addition the opening of the first valve means become too abrupt.
- The object of the invention is therefore to provide an improved hydraulic assistance device for a dual circuit of the type known as "full power" which is capable of operating as a conventional master cylinder in the event of failure of the high pressure circuit and in which the feature of pedal feel is assured.
- According to the invention there is provided a hydraulic assistance device comprising a body comprising a bore in which a first piston means and a second piston means are slideably mounted, the first piston means being movable under the effect of the actuation of third piston slideably mounted in the body, and the second piston means being movable by the intermediary of a hydraulic connection formed in a pressure chamber defined between the first and the second piston means, a respective valve means being associated with each piston means in a respective hydraulic circuit between a source of fluid under pressure and a respective braking circuit ; and a third chamber defined in the bore between the first piston means and the third piston, the said third chamber being connected to a low pressure reservoir through a passage in which a valve means is mounted, characterized in that the device incorporates a second valve means in a second passage between the third chamber and the reservoir, the second valve means being responsive to the pressure of the corresponding source of pressure so that, upon failure of this high pressure source, the second valve means closes so as to isolate the third chamber from the reservoir.
- According to a second embodiment of the invention the first piston means further comprises a control piston on which is fixedly mounted a ball adapted to close a valve seat in the first piston means to thereby close the fluid passage between the first pressure chamber and the third chamber.
- The invention will now be described by way of example with reference to the accompanying drawings, in which :
- -Figure 1 is a longitudinal sectional view of a hydraulic assistance device according to a first embodiment of the invention, and
- -Figure 2 is a longitudinal sectional view of a device according to a second embodiment of the invention.
- As shown in Figure 1, the hydraulic assistance device, which in the example shown is a master cylinder for a braking circuit, comprises a
body 10 including asingle bore 12 which is closed at one end by aclosure component 14. A first piston 16 is slideably mounted in thebore 12 and is intended to be connected to a brake pedal of a vehicle (not shown). A first piston means and a second piston means 18, 20 are slideably mounted in thebore 12 defining between them afirst pressure chamber 22. Asecond pressure chamber 24 is defined between the second piston means 22 and theclosure component 14. The first piston means 18 comprises a control piston 26 which includes, in aninternal bore 27 connecting thefirst chamber 22 to a low pressure reservoir 25 (not shown), a ball 28 which is pushed to the right, (when viewing the drawings), by aspring 30. A control component 32 is slideably mounted inbore 27 and has at its end aseat 34, which is capable of being closed by theball 30 and connected to achamber 36 in thebore 12 by aninternal passage 38. The control component 32 is connected to the first piston 16 by aspring 40 and comprises anannular seal 42 which is capable of closing the passage between thepassage 38 and thechamber 40 by coming into abutment against anannular shoulder 44, at the rear of the control piston 26. - The first piston means 18 defines with the
bore 12 anannular space 46 which is bounded axially by two annular cups 48, 50 and is connected to a source of high pressurehydraulic fluid 52 by apassage 54 in thebody 10. The first piston means 18 also includes a bore 56 which is in hydraulic communication with theannular space 46 by way of alateral opening 58 and which includes aball 60 which is normally pushed towards aseat 62 by a spring 64. The control piston 26 comprises arod 66 which, when the control piston moves to the left, lifts theball 60 from itsseat 62 and allows fluid to pass under pressure from thesource 52 through apassage 68, thefirst pressure chamber 22 and twooutlets primary braking circuit 74. - The second piston means 20 comprises a
stepped bore 76 in which acontrol piston 78 is slideably mounted in a sealed manner, and which includes astepped bore 80 and alateral opening 82 which together join thesecond chamber 24 to thereservoir 25. Aball 84 is mounted in thebore 76, theball 84 being retained by apiston component 86 and normally pushed to the right by aspring 88 so as to open aseat 90 formed in thebore 80 of thecontrol piston 78. A spring 92 connects the first and second piston means 18, 20. - The
closure component 14 includes astepped bore 94 which is connected to a high pressure source offluid 96 and which comprises a first valve means 98 and aball valve 100 which is normally pushed towards its closed position by aspring 102. Thecontrol piston 78 comprises arod 104 which, when the control piston moves to the left, opens theball valve 100 and allows the fluid under pressure to pass through thesecond chamber 24 and twoports secondary braking circuit 110. - According to the invention, the hydraulic assistance device also includes in the body 10 a valve means generally indicated by
reference 112. The valve means 112 comprises a stepped bore 114 in which avalve 116 is slideably mounted and which includes twoannular cups spring 122 which normally pushes the valve to the left, (when viewing the drawings). Oneend 124 of the bore 114 is connected by way of apassage 126 and theannular space 46 to thehigh pressure source 52. Theother end 128 of the bore 114 is connected to thechamber 40 through apassage 130. A third passage 132 connects the central portion 134 of the bore 114 to thelow pressure reservoir 25. If thevalve 116 moves to the left, thecup 120 comes into contact with an annular wall 136 of the stepped bore 114 and isolates thechamber 40 from thereservoir 25. Thehigh pressure source 52 is isolated from thereservoir 25 and from thechamber 36 by thecup 118, the high pressure of this source simply pushing thevalve 116 to the right against the force of thespring 122. - The device described above operates as follows. A force applied by the brake pedal onto the piston 16 is transmitted by the
spring 40 to thecontrol component 42 which moves to the left, and closes the ball valve 28. The control piston 26 then moves relative to the first piston means 18 and opens theball 60 by way of therod 66. Opening theball 60 allows fluid under pressure to pass from thesource 52 through theopening 58, thepassage 68, thefirst pressure chamber 22 and theports brakes 74. The rise in pressure of the primary circuit causes the retraction of the control piston 26 which is in equilibrium with thepedal feel spring 40. The rise in pressure in thepressure chamber 22 also results in movement of the second piston means 20 and thus closure of theball valve 84 and movement of thesecond control piston 78 to the left This movement of thecontrol piston 78 opens theball 100 by way of therod 104. Opening theball 100 allows fluid under pressure to pass from thesource 96 to thebrakes 110 through thesecond pressure chamber 24 in which the fluid pressure will rise until equilibrium is obtained between the pressures of theprimary circuit 74 and thesecondary circuit 110. After the brake pedal is released, the two circuits are resup- plied by the reopening of the twoball valves 28 and 84. - In normal operation, the valve means 112 remains in its open position as shown, the force of the high pressure fluid being greater than that of the
spring 122. Thechamber 40 is thus in hydraulic communication with thereservoir 25 and suitable pedal feel is provided by thespring 40. In the case of rapid braking, theannular cup 42, which normally remains open during operation of the device, closes, the rise in pressure of theprimary braking circuit 74 being insufficiently rapid to create a reaction force on thecontrol component 38. However the valve means 12 remains open allowing fluid to pass from thechamber 36 to thereservoir 25 and the spring for pedal feel remains operative. - In the case of failure of the
high pressure circuit 52 thespring 122 closes thevalve 112 since no fluid under pressure remains in thepassage 126. When the device is operated, theannular cup 42 closes owing to the absence of reaction upon the control piston 26. Thechamber 36 is thus isolated and a hydrostatic connection is formed between the piston 16 and the first piston means 18 rendering thespring 40 inoperative. - Another advantage of the present invention compared with the prior art lies in the fact that the piloting of the
secondary circuit 110 occurs over the whole of the transverse section of the second piston means 20, which, when the device is operated reduces the effect of friction of the seals of this second piston means and the effect of sudden opening of theball valve 100 of the secondary circuit. - A second embodiment of the invention is shown in Figure 2 in which components common to the embodiment of Figure have the same reference numerals.
- Despite its advantages the previous embodiment has a relatively large number of components resulting in increased manufacturing costs. The following embodiment was designed with a view to reducing both the number of components and the size of the device.
- As shown in Figure 2 the first piston means 18 is simplified with respect to that of the embodiment of Figure 1 and comprises a
control component 232 slideably mounted in astepped bore 200. Thecontrol component 232 is connected to the first piston 16 byspring 40. The first piston means 18 further comprises acontrol piston 226 slideably mounted instepped bore 200 and receiving, in its end adjacent thecontrol component 232, aball 228 adapted to close against avalve seat 202 in thecontrol component 232 and thus close the fluid passage between thefirst pressure chamber 22 andchamber 36.Chamber 36 communicates with thelow pressure reservoir 25 by way of apassage 130, a valve means 112 and a passage 130'. A second return passage to thelow pressure reservoir 25 is provided by way of an opening 234, atilting valve 236 and apassage 238. - The provision of two return passages to the
low pressure reservoir 25 allows the omission of the valve means 42 which in the previous embodiment was needed to closechamber 40. The absence of thisvalve 40 allows the first piston means 18 to be shortened.Ball 228 is of a considerably smaller diameter than its equivalent, ball 28, in the first embodiment and this fact, together with that of the ball being mounted on thecontrol piston 226 allows a reduction in the size and number of components of the first piston means 18. The risk of leaks with a small diameter ball valve is also less than that with a larger diameter ball. - When the device is operated, the movement of the first piston 16 to the left (when viewing the drawings) results in the movement to the left of the
control piston 226 which opensball valve 60 and allows fluid under pressure to pass from thehigh pressure source 52, through opening 58 andfirst pressure chamber 22 to the vehicle'sprimary braking circuit 74. - The second piston means 20 is also simplified with respect to that of the previous embodiment. A
control piston 78 is slideably mounted in the second piston means 20 by way of anannular component 204 which is mounted in an end of the second piston means 20. In the end of thecontrol piston 78 adjacent the second piston means 20 is mounted aball 284 which is adapted to close against avalve seat 290 in the second piston means 20 to thus close the fluid passage between thesecond pressure chamber 24 and thelow pressure reservoir 25. The other end of thecontrol piston 78 is slideably received in asleeve 206 which also receives, at its other end, anactuator element 208 which, when the device is operated, opensball valve 210 to allow fluid under pressure to flow from thehigh pressure source 96 to the vehicle'ssecondary braking circuit 110. As was the case for the first piston means 18, the small diameter ofball 284 and the fact that it is mounted on thecontrol piston 78 results in a reduction of the size of the device and its number of components. - The telescoping, sliding relationship between
control piston 78 andsleeve 206 results in the simplification of the structure ofclosure component 14 while allowing sufficient travel for the second piston means in the event of a high pressure circuit failure whereupon the device operates as a conventional master cylinder in a hydrostatic mode. - The device operates in a similar way to that of the first embodiment, apart from the following differences. In the event of a failure of the primary
high pressure source 52, theball valve 228 remains open while valve means 112 closes under the effect ofspring 122. Tiltingvalve 236 closes when the first piston means 18 moves away from its illustrated rest position. Thus the first piston 16 becomes the piston of a conventional, hydrostatic master cylinder and fluid passes fromchamber 36 viavalve seat 202 andopening 58 to theprimary braking circuit 74. This method of operation results in a reduction of brake pedal dead stroke. During a release of braking, valve means 112 remains closed andchamber 22 is replenished by way of tiltingvalve 236. During the first part of the return of the first piston means 18, the tiltingvalve 236 is opened as a result of the pressure differential across it . At the end of its return stroke the first piston means abuts anextension 240 of tiltingvalve 236 and thus holds it in its open position. - In the event of a failure of the secondary
high pressure source 96,ball 284 closes againstseat 290 when the device is operated and the second piston means 20 moves to the left (when viewing the drawings) and conveys fluid under pressure to thesecondary braking circuit 110. - Thus it will be seen that the modified construction of the second embodiment results in a more compact assembly and a reduction in the number of components while ensuring optimum operation in both the hydrodynamic and hydrostatic modes.
Claims (8)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8502824A FR2577872B1 (en) | 1985-02-27 | 1985-02-27 | HYDRAULIC ASSISTANCE DEVICE |
FR8502824 | 1985-02-27 | ||
FR8514947A FR2588227B2 (en) | 1985-10-09 | 1985-10-09 | HYDRAULIC ASSISTANCE DEVICE |
FR8514947 | 1985-10-09 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0197803A1 true EP0197803A1 (en) | 1986-10-15 |
EP0197803B1 EP0197803B1 (en) | 1988-01-20 |
Family
ID=26224396
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19860400303 Expired EP0197803B1 (en) | 1985-02-27 | 1986-02-12 | Hydraulic assistance device |
Country Status (7)
Country | Link |
---|---|
US (1) | US4671168A (en) |
EP (1) | EP0197803B1 (en) |
JP (1) | JPH0655588B2 (en) |
KR (1) | KR940008816B1 (en) |
AU (1) | AU570355B2 (en) |
DE (1) | DE3660016D1 (en) |
ES (1) | ES8706240A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0247913A1 (en) * | 1986-05-28 | 1987-12-02 | BENDIX France Société Anonyme dite: | Hydraulic pressure booster |
FR2653725A1 (en) * | 1989-10-31 | 1991-05-03 | Bendix France | BRAKE CIRCUIT WITH HYDRAULIC AMPLIFICATION AND BRAKE ASSEMBLY COMPRISING SUCH A CIRCUIT. |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2577499B1 (en) * | 1985-02-20 | 1987-04-17 | Bendix France | HYDRAULIC ASSISTANCE DEVICE |
DE3545975A1 (en) * | 1985-12-23 | 1987-07-02 | Rexroth Mannesmann Gmbh | HYDRAULIC TWO-CIRCUIT FORCE BRAKE VALVE IN TANDEM DESIGN |
FR2614591A1 (en) * | 1987-04-28 | 1988-11-04 | Bendix France | HYDRAULIC BRAKE DEVICE FOR VEHICLE |
JP2740221B2 (en) * | 1988-12-28 | 1998-04-15 | 曙ブレーキ工業株式会社 | Brake fluid pressure control device |
US4961317A (en) * | 1989-09-18 | 1990-10-09 | Savair, Inc. | Oleopneumatic intensifier cylinder |
US5400595A (en) * | 1994-02-25 | 1995-03-28 | Deere & Company | Brake valve with prefill chamber unloading |
FR2892160B1 (en) * | 2005-10-19 | 2008-01-18 | Valeo Embrayages | HYDRAULIC CLUTCH CONTROL DEVICE. |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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FR2130236A1 (en) * | 1971-03-18 | 1972-11-03 | Bendix Corp | |
FR2164879A1 (en) * | 1971-12-24 | 1973-08-03 | Teves Gmbh Alfred | |
US4075848A (en) * | 1975-02-07 | 1978-02-28 | Aisin Seiki Kabushiki Kaisha | Hydraulic brake booster |
GB2001721A (en) * | 1977-07-30 | 1979-02-07 | Teves Gmbh Alfred | Hydraulic brake booster |
FR2558785A1 (en) | 1984-01-31 | 1985-08-02 | Dba | HYDRAULIC ASSISTANCE DEVICE |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2574969A (en) * | 1948-12-20 | 1951-11-13 | Hydraulic Brake Co | Tilting valve master cylinder for hydraulic brakes |
US2992533A (en) * | 1956-06-06 | 1961-07-18 | Dunlop Rubber Co | Fluid pressure control mechanism |
-
1986
- 1986-02-06 US US06/827,128 patent/US4671168A/en not_active Expired - Fee Related
- 1986-02-12 EP EP19860400303 patent/EP0197803B1/en not_active Expired
- 1986-02-12 DE DE8686400303T patent/DE3660016D1/en not_active Expired
- 1986-02-12 KR KR1019860000975A patent/KR940008816B1/en not_active IP Right Cessation
- 1986-02-14 AU AU53499/86A patent/AU570355B2/en not_active Ceased
- 1986-02-26 ES ES552425A patent/ES8706240A1/en not_active Expired
- 1986-02-27 JP JP4276386A patent/JPH0655588B2/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2130236A1 (en) * | 1971-03-18 | 1972-11-03 | Bendix Corp | |
FR2164879A1 (en) * | 1971-12-24 | 1973-08-03 | Teves Gmbh Alfred | |
US4075848A (en) * | 1975-02-07 | 1978-02-28 | Aisin Seiki Kabushiki Kaisha | Hydraulic brake booster |
GB2001721A (en) * | 1977-07-30 | 1979-02-07 | Teves Gmbh Alfred | Hydraulic brake booster |
FR2558785A1 (en) | 1984-01-31 | 1985-08-02 | Dba | HYDRAULIC ASSISTANCE DEVICE |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0247913A1 (en) * | 1986-05-28 | 1987-12-02 | BENDIX France Société Anonyme dite: | Hydraulic pressure booster |
FR2653725A1 (en) * | 1989-10-31 | 1991-05-03 | Bendix France | BRAKE CIRCUIT WITH HYDRAULIC AMPLIFICATION AND BRAKE ASSEMBLY COMPRISING SUCH A CIRCUIT. |
EP0426513A1 (en) * | 1989-10-31 | 1991-05-08 | Alliedsignal Europe Services Techniques | Brake circuit with hydraulic assistance and brake unit comprising the same |
Also Published As
Publication number | Publication date |
---|---|
JPH0655588B2 (en) | 1994-07-27 |
AU5349986A (en) | 1986-09-04 |
KR940008816B1 (en) | 1994-09-26 |
EP0197803B1 (en) | 1988-01-20 |
US4671168A (en) | 1987-06-09 |
KR860006642A (en) | 1986-09-13 |
DE3660016D1 (en) | 1988-02-25 |
ES552425A0 (en) | 1987-05-16 |
JPS61205544A (en) | 1986-09-11 |
AU570355B2 (en) | 1988-03-10 |
ES8706240A1 (en) | 1987-05-16 |
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