US3855797A - Hydraulic master cylinder - Google Patents

Hydraulic master cylinder Download PDF

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Publication number
US3855797A
US3855797A US00422216A US42221673A US3855797A US 3855797 A US3855797 A US 3855797A US 00422216 A US00422216 A US 00422216A US 42221673 A US42221673 A US 42221673A US 3855797 A US3855797 A US 3855797A
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United States
Prior art keywords
chamber
piston
plunger
valve
bore
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Expired - Lifetime
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US00422216A
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English (en)
Inventor
G Papiau
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DEA SA
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DEA SA
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    • 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
    • B60T13/142—Systems with master cylinder
    • B60T13/145—Master cylinder integrated or hydraulically coupled with booster
    • B60T13/146—Part of the system directly actuated by booster pressure

Definitions

  • the master-cylinder comprises a body defining a cavity therewithin, a bore opening into the cavity, a floating piston slidable in the bore to define a first chamber and a second chamber including the cavity, a spool valve for controlling fluid pressure in the second chamber upon actuation of a control rod, a lever mechanism interconnecting the rod, the piston and the valve for opening the latter, and a cut-off valve located in the first chamber for controlling the fluid flowing out from the first chamber.
  • the cut-off valve includes a valve seat surrounding the outlet port of the first chamber and a valve member secured to a plunger slidable in an inner bore located in the floating piston, the inner bore opening at one end into said first chamber and at the other end into a compartment communicating with a low pressure reservoir and a spring biasing the plunger in abutment with a stop fixed relative to the floating piston.
  • the invention relates to a hydraulic master-cylinder for supplying hydraulic pressure fluid to two independent utilising circuits, for example, two brake circuits in a motor vehicle.
  • Known master-cylinders comprise a body containing a bore in which two pistons are slidable, so as to define in the bore two independent pressure chambers for the pistons.
  • One piston known as the controlling or actuating piston, is connected to a controlling member, while the other floats in the bore in the body.
  • Mastercylinders of this type have the disadvantage of considerably shortening the stroke of the controlling member in the event of failure of one of the utilising circuits connected to the pressure chambers.
  • An object of the invention is to provide a hydraulic master-cylinder in which the floating piston can be locked in position hydraulically in the event of failure of the circuit associated with the chamber defined between the bore end and the floating piston, so that there is a very substantial reduction in the idle movement of the controlling member when the other utilising circuits is operated.
  • the invention proposes a hydraulic master-cylinder for a split system having two separate utilising circuits, comprising a body with a bore therein, said bore having at one end a bottom, a floating piston slidably mounted in said bore to define therein a first pressure chamber, located between said piston and the bottom of said bore, and a second chamber, means for generating pressure into said second chamber upon actuation of an operator-operated controlling member, said first and second chambers communicating with said utilising circuits through first and second outlet ports respectively, and a cut-off valve controlled both by motions of the floating piston out of its idle position and by the fluid pressure in the first chamber, said cut-off valve impeding fluid to flow through said first outlet port when the fluid pressure in the first chamber, for a given motion of the floating piston, is less than a predetermined value.
  • FIGURE represents a longitudinal section through a servo master-cylinder for a dual brake circuit in a motor vehicle.
  • the servo master-cylinder illustrated in the FIGURE comprises a body containing two parallel bores 12, 14 both leading into a cavity 16 closed by a cover 18.
  • a floating piston 20 is mounted in the bore 12 and cooperates with the bottom 24 of this bore to define a primary pressure chamber 22 and with the cavity 16 to define a secondary pressure chamber 26.
  • the two pressure chambers 22, 26 are connected by respective outlet orifices 28, 30 to two independent brake circuits (not shown) in a motor vehicle.
  • the mastercylinder comprises a cut-off valve capable of preventing fluid from passing out of the primary chamber 22 towards the orifice 28.
  • the cut-off valve comprises a valve member 32 capable of abutting directly on a seat 34 provided on the bottom of the body.
  • the valve member 32 comprises a cupshaped elastomeric portion 36 capable of masking the entrance 38 of the duct which connects the chamber 22 to the orifice 28. It should be noted that the elastomeric portion, in addition to ensuring a good seal when the valve is closed, permits the effective area of the cut-off valve to be selected as desired.
  • the valve member 32 is mounted in the body by way of a retractable resilient connection.
  • the valve member 32 is attached to a projection 39 belonging to a plunger 40, which is slidable in a fluid-tight manner in a longitudinal, blind bore 42 in the piston 20.
  • This bore 42 gives onto the pressure chamber 22.
  • the plunger 40 and the end of the bore 42 together define a cavity 44 which communicates through radial orifices 46 with an annular space 48 situated between the fluid-tight bearing members 50, 52 of the piston.
  • the space 48 normally communicates through passage 53 to port connected to a reservoir (not shown) for hydraulic brake fluid at low pressure (generally atmospheric pressure), so that if necessary the chamber 22 can be replenished by way of ducts 54 and by resilient lifting of a cup seal 56.
  • low pressure generally atmospheric pressure
  • the retractable resilient connection also comprises a spring 58 bearing on the end of the bore 42 and urging the plunger 40 out of this bore onto a shoulder 60 fixed relative to the piston 20.
  • the shoulder consists of the central portion of a sleeve 62, whose periphery 64 both provides an abutment for a piston return spring 66 and retains the resilient cup 56.
  • the return spring 66 which also bears on the body, urges the piston 20 into the idle position illustrated in the FIGURE, in which it bears on a stop 67 screwed on the body. In this idle position, when the brakes of the vehicle are off, the cut-off valve is open and the valve member 32 is a few millimetres off its seat, since the initial compression of the spring 66 is greater in this case than that of the spring 58.
  • the plunger 40 is used as means responsive to the fluid pressure in the primary chamber 22 so as to control the valve member 32.
  • the effective crosssection B of the plunger 40 is made substantially equal to the effective cross-section A of the cut-off valve.
  • the invention is described with reference to a servo master-cylinder which receives pressure fluid from a pressure source (not shown), an accumulator for instance, by way of a supply orifice 68 and discharges it through an orifice 70 connected to a low pressure reservoir (not shown). Since a brake assisting servo control mechanism of the same type, and its operation, are described in French Patent Specification No. 1,436,608, they will not be described in detail here.
  • the pressure rise in the fluid in the chamber 26 is controlled by a spool valve 72 mounted in a sleeve 73 fixed inside the bore 14.
  • the valve 72 is moved by a mechanism 74 according to the relative motion of the piston 20 and of a controlling member 76 connected to the brake pedal of the vehicle.
  • One end 92 of the member 76 projects into the second chamber 26 and is provided with a spline 43 adapted to receive parts of the mechanism 74. For sake of clarity only half of the end 92 is shown on the FIGURE and partially in dotted lines.
  • the mechanism 74 essentially comprises, firstly, an arm 78 of which one end 80 is fork-shaped and pivoted on an element 82 and the other end is mounted on a pivot 83 fixed to the member 76 and, secondly, a double sensor 84, whose ends comprise cam-forming surfaces co-operating with the valve 72 and piston 20 respectively.
  • the double sensor is pivoted on a pin 86 fixed to the arm 78.
  • a given shift of the push rod 76 is accompanied by a given shift of the piston and pressurisation of the chambers 22, 26.
  • the ratio between the stroke of the push rod 76 and that of the piston 20 is slightly less than unity in the present case, as the piston moves faster than the push rod.
  • This stroke ratio is a function of the lever arm ratio of the arm 78 (that is to say, the position of the pivot 86 relative to the points at which the ends 80, 81 are pivoted) and the lever arm ratio of the double sensor.
  • the spring 90 is compressed to enable the mechanism 74 to retract without being damaged when the free end 92 of the push rod 76 operates the piston 20 by direct engagement.
  • the calibration of the spring 58 is such that for a given pressure in the chamber 22, depending on the piston stroke and on the absorption in the circuit, there is relative motion of the valve member 32 towards the piston 20 at least equal to the said stroke.
  • Clearance is also provided between the valve member 32 and its seat 34 to prevent undesired closing of the valve during the temporary pressure rise phase. The brakes in the circuit associated with the chamber 22 therefore operate properly. The same applies when the piston 20 is operated directly by the push rod 76.
  • the invention may also be applied to a non-servo tandem master-cylinder.
  • the master-cylinder comprises a body containing a bore in which two pistons are slidable so as to define two independent pressure chambers in the bore.
  • One of the pistons termed the controlling piston, is connected to the controlling member, whereas the other floats in the bore.
  • the floating piston is associated with a cut-off valve of the type described above, so as to control the discharge of fluid from the primary chamber defined be tween the floating piston and the bore end.
  • hydraulic locking of the floating piston in position permits the pressure to rise in the other chamber without appreciably shortening the stroke of the controlling member. The driver then has a long enough pedal stroke for correct operation of the brake circuit which is still operative.
  • a housing defining a bore therewithin
  • a piston slidably mounted in said bore and cooperating with opposite ends of the latter to define a pair of pressure chambers;
  • valve means shiftable from a condition venting the other chamber to a fluid reservoir to a position communicating said other chamber with a source of fluid pressure to thereby shift said piston to develop fluid pressure in said one chamber;
  • a pressure differential responsive plunger having a pair of opposed faces slidably mounted on said piston, and resilient means yieldably urging said plunger to a predetermined position with respect to the piston, one of said faces being exposed to the fluid pressure level in said one chamber, the other face of said plunger being communicated with the fluid pressure level in said resevoir;
  • cut-off valve means carried by said plunger for cooperation with said outlet to terminate communication therethrough when the fluid pressure level in said one chamber drops below a predetermined level for a given movement of the piston.
  • said piston defining a cavity opening into said one chamber, said plunger being slidably mounted in said cavity and cooperating with the end of the latter to define a fluid-receiving compartment, said compartment being communicated to said reservoir.
  • valve seat circumscribing said outlet, the crosssectional area of said valve seat being substantially equal to the cross-sectional area of said plunger;
  • said cut-off valve means sealingly engaging said valve sponding shoulder on the plunger.

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Transmission Of Braking Force In Braking Systems (AREA)
  • Braking Systems And Boosters (AREA)
US00422216A 1972-12-18 1973-12-06 Hydraulic master cylinder Expired - Lifetime US3855797A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7245051A FR2210727B1 (hu) 1972-12-18 1972-12-18

Publications (1)

Publication Number Publication Date
US3855797A true US3855797A (en) 1974-12-24

Family

ID=9108872

Family Applications (1)

Application Number Title Priority Date Filing Date
US00422216A Expired - Lifetime US3855797A (en) 1972-12-18 1973-12-06 Hydraulic master cylinder

Country Status (9)

Country Link
US (1) US3855797A (hu)
JP (1) JPS5232428B2 (hu)
BR (1) BR7309746D0 (hu)
DE (1) DE2362350C2 (hu)
ES (1) ES421580A1 (hu)
FR (1) FR2210727B1 (hu)
GB (1) GB1393640A (hu)
IT (1) IT1002251B (hu)
SE (1) SE406061B (hu)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4137718A (en) * 1976-04-10 1979-02-06 Itt Industries, Inc. Power brake unit
US4191020A (en) * 1976-07-14 1980-03-04 Daimler-Benz Aktiengesellschaft Servo brake system
DE2952364A1 (de) * 1979-12-24 1981-08-06 Wabco Fahrzeugbremsen Gmbh, 3000 Hannover Geberzylinder fuer die aussteuerung von druckmittel
US4462300A (en) * 1981-09-17 1984-07-31 Itt Industries, Inc. Hydraulic power booster with a mechanically operated separate brake control valve member
FR2565914A1 (fr) * 1984-06-14 1985-12-20 Teves Gmbh Alfred Dispositif de freins a assistance hydraulique
US4649707A (en) * 1984-03-10 1987-03-17 Alfred Teves Gmbh Brake pressure generator having an improced master cylinder and booster for an automotive hydraulic brake system
US4891945A (en) * 1986-08-11 1990-01-09 Alfred Teves Gmbh Boost-failure responsive fluid tapping valve in tandem master cylinder with booster piston at pedal-remote end of master cylinder
US5305606A (en) * 1991-08-16 1994-04-26 Alfred Teves Gmbh Actuating unit for hydraulic brake systems
US6126412A (en) * 1997-12-10 2000-10-03 Caterpillar Inc. Fluid driven piston assembly and fuel injector using same

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2447445C2 (de) * 1974-10-04 1985-07-04 geb. Sewerin Frieda 3257 Springe Hildebrandt Schutzvorrichtung für Kolbenstangen von hydraulischen oder pneumatischen Arbeitszylindern
DE2519836C2 (de) * 1975-05-03 1985-06-27 Alfred Teves Gmbh, 6000 Frankfurt Hydraulischer Bremskraftverstärker
FR2338402A1 (fr) * 1976-01-16 1977-08-12 Dba Amplificateur hydraulique
GB1589602A (en) * 1977-05-25 1981-05-13 Girling Ltd Control valve assemblies for hydraulic braking systems
FR2483868A1 (fr) * 1980-06-06 1981-12-11 Dba Amplificateur hydraulique de freinage
DE3108908A1 (de) * 1981-03-09 1982-09-30 Alfred Teves Gmbh, 6000 Frankfurt Hydraulischer kraftverstaerker
DE3128317A1 (de) * 1981-07-17 1983-01-27 Alfred Teves Gmbh, 6000 Frankfurt Hydraulischer kraftverstaerker
DE3221373A1 (de) * 1981-09-17 1983-12-08 Alfred Teves Gmbh, 6000 Frankfurt Hebelbetaetigung fuer ein bremsventil eines hydraulischen kraftverstaerkers
DE3315730C2 (de) * 1983-04-29 1993-10-21 Teves Gmbh Alfred Hydraulischer Kraftverstärker
DE3338322A1 (de) * 1983-10-21 1985-05-02 Alfred Teves Gmbh, 6000 Frankfurt Druckmittelbetaetigbare fahrzeugbremsanlage
DE3433439C2 (de) * 1984-09-12 1994-06-30 Teves Gmbh Alfred Hydraulischer Verstärker, insbesondere für Bremsanlagen von Kraftfahrzeugen
DE3437834A1 (de) * 1984-10-16 1986-04-17 Alfred Teves Gmbh, 6000 Frankfurt Mehrwegeventil, insbesondere fremdkraftgesteuertes bremsventil
DE3600924A1 (de) * 1986-01-15 1987-07-16 Teves Gmbh Alfred Hydraulischer kraftverstaerker
DE3912233A1 (de) * 1989-04-14 1990-10-18 Teves Gmbh Alfred Hydraulischer verstaerker, insbesondere fuer schlupfgeregelte bremsanlagen

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2410269A (en) * 1944-04-28 1946-10-29 Automotive Prod Co Ltd Liquid pressure servomotor device
FR1105351A (fr) * 1954-07-22 1955-11-30 Fabrications Unicum Soc D Perfectionnements aux variateurs de vitesse à entraînement par friction
US3216194A (en) * 1962-09-25 1965-11-09 Girling Ltd Master cylinders for hydraulic braking systems
US3427807A (en) * 1961-06-30 1969-02-18 Girling Ltd Connecting member,e.g.,for pipes or the like
US3610101A (en) * 1970-03-09 1971-10-05 Bendix Corp Safety device for hydraulic brake booster
US3698190A (en) * 1970-03-25 1972-10-17 Aisin Seiki Tandem master cylinder

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2347349A (en) * 1942-02-02 1944-04-25 Bendix Aviat Corp Master cylinder
CH318682A (de) * 1953-09-17 1957-01-15 Beka St Aubin Ag Bremseinrichtung mit durchgehender hydraulischer Bremsleitung an Zugfahrzeugen mit Anhänger
GB994872A (en) * 1960-09-21 1965-06-10 Automotive Prod Co Ltd Master cylinders for hydraulic brake mechanisms
FR88761E (hu) * 1965-02-05 1967-06-07
GB1203889A (en) * 1967-10-30 1970-09-03 Bendix Corp Improvements in and relating to fluid pressure control valves
CA942355A (en) * 1971-04-12 1974-02-19 Bendix Corporation (The) Hydraulic master cylinder
FR2141595B1 (hu) * 1971-06-18 1974-03-08 Dba

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2410269A (en) * 1944-04-28 1946-10-29 Automotive Prod Co Ltd Liquid pressure servomotor device
FR1105351A (fr) * 1954-07-22 1955-11-30 Fabrications Unicum Soc D Perfectionnements aux variateurs de vitesse à entraînement par friction
US3427807A (en) * 1961-06-30 1969-02-18 Girling Ltd Connecting member,e.g.,for pipes or the like
US3216194A (en) * 1962-09-25 1965-11-09 Girling Ltd Master cylinders for hydraulic braking systems
US3610101A (en) * 1970-03-09 1971-10-05 Bendix Corp Safety device for hydraulic brake booster
US3698190A (en) * 1970-03-25 1972-10-17 Aisin Seiki Tandem master cylinder

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4137718A (en) * 1976-04-10 1979-02-06 Itt Industries, Inc. Power brake unit
US4191020A (en) * 1976-07-14 1980-03-04 Daimler-Benz Aktiengesellschaft Servo brake system
DE2952364A1 (de) * 1979-12-24 1981-08-06 Wabco Fahrzeugbremsen Gmbh, 3000 Hannover Geberzylinder fuer die aussteuerung von druckmittel
US4462300A (en) * 1981-09-17 1984-07-31 Itt Industries, Inc. Hydraulic power booster with a mechanically operated separate brake control valve member
US4649707A (en) * 1984-03-10 1987-03-17 Alfred Teves Gmbh Brake pressure generator having an improced master cylinder and booster for an automotive hydraulic brake system
FR2565914A1 (fr) * 1984-06-14 1985-12-20 Teves Gmbh Alfred Dispositif de freins a assistance hydraulique
US4891945A (en) * 1986-08-11 1990-01-09 Alfred Teves Gmbh Boost-failure responsive fluid tapping valve in tandem master cylinder with booster piston at pedal-remote end of master cylinder
US5305606A (en) * 1991-08-16 1994-04-26 Alfred Teves Gmbh Actuating unit for hydraulic brake systems
US6126412A (en) * 1997-12-10 2000-10-03 Caterpillar Inc. Fluid driven piston assembly and fuel injector using same

Also Published As

Publication number Publication date
FR2210727B1 (hu) 1978-03-10
IT1002251B (it) 1976-05-20
JPS50129873A (hu) 1975-10-14
JPS5232428B2 (hu) 1977-08-22
DE2362350C2 (de) 1983-10-27
FR2210727A1 (hu) 1974-07-12
GB1393640A (en) 1975-05-07
ES421580A1 (es) 1976-04-01
BR7309746D0 (pt) 1974-08-29
SE406061B (sv) 1979-01-22
DE2362350A1 (de) 1974-06-27

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