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
  • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
  • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
  • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
  • B60T8/38—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition including valve means of the relay or driver controlled type
• • 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
  • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
  • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
  • B60T11/16—Master control, e.g. master cylinders
  • B60T11/20—Tandem, side-by-side, or other multiple master cylinder units
• • 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
  • B60T7/00—Brake-action initiating means
  • B60T7/02—Brake-action initiating means for personal initiation
  • B60T7/04—Brake-action initiating means for personal initiation foot actuated
  • B60T7/042—Brake-action initiating means for personal initiation foot actuated by electrical means, e.g. using travel or force sensors
• • 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
  • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
  • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
  • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
  • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
  • B60T8/4072—Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking

Definitions

• the present invention relates to a tandem master cylinder for an electro-hydraulic braking system.
• a tandem master cylinder for an electro-hydraulic braking system is already known in the prior art, of the type comprising: a body delimiting primary and secondary pressure chambers separated by an axially displaceable piston, called a secondary piston,
• the secondary piston being axially movable between a rest position, in which the mobile and fixed closure means are spaced from each other, and a position of cooperation of these movable and fixed sealing means.
• the driver controls the braking of the vehicle by actuating a brake pedal connected to the secondary piston.
• the action of the brake pedal is transmitted to a hydraulic braking circuit by various means.
• a braking system comprising a master cylinder of the aforementioned type can operate in normal and emergency configurations.
• the hydraulic braking circuit is isolated from the master cylinder.
• the action of the brake pedal is transmitted to the hydraulic braking circuit by means of electrical means.
• the hydraulic braking circuit When the braking system is in emergency operation configuration, the hydraulic braking circuit is connected to the master cylinder. The action of the brake pedal is transmitted to the hydraulic brake circuit via the brake fluid contained in this master cylinder.
• the fixed closure means comprise an annular support seat formed in the body and the mobile closure means comprise an O-ring, carried by the secondary piston, intended to cooperate with this support seat.
• the action of the driver on the brake pedal causes the secondary piston to move in a short stroke allowing the movable and fixed shutter means to remain spaced apart from one another and therefore to the means hydraulic connection to remain open.
• the simulation means make it possible to restore to the driver, actuating the brake pedal, a braking sensation such as that which he would feel in the case of a master cylinder connected to the hydraulic braking circuit.
• the action of the driver on the brake pedal causes the displacement of the secondary piston in a long stroke at the end of which the movable and fixed shutter means cooperate with one another to close the means for hydraulic connection of the primary pressure chamber with means for simulating braking force.
• the object of the invention is to limit the stroke of the secondary piston as much as possible when the driver actuates the brake pedal in emergency operation configuration, in order to limit the amount of brake fluid transferred from the primary pressure chamber to the means. braking force simulation.
• the subject of the invention is a tandem master cylinder for an electro-hydraulic braking system, of the aforementioned type, characterized in that the secondary piston has two parts which can be moved axially relative to one another to adjust the axial position relative movable and fixed closure means when the secondary piston is in its rest position.
• the two parts of the secondary piston respectively comprise male and female members for connecting these two parts of the secondary piston provided with complementary screwing surfaces so that the male member forms a screw and the female member forms a nut;
• the master cylinder comprises means for immobilizing the male and female organs in a predetermined relative position;
• the immobilization means comprise a lock nut screwed onto the male member bearing against the female member;
• the immobilization means comprise at least one radial deformation of one of the screwing surfaces of the male and female organs;
• the fixed closure means comprise an annular support seat formed in the body and the mobile closure means comprise an O-ring, carried by the secondary piston, intended to cooperate with this support seat;
• a first part of the secondary piston is intended to cooperate with a rest stop secured to the body, the second part of the secondary piston carrying the movable closure means;
• the rest stop comprises a pin, integral with the body, extending substantially transversely to the direction of movement of the secondary piston in an oblong housing formed in the first part of this piston;
• the oblong housing is in communication with a brake fluid supply chamber, called the secondary supply chamber, the first part of the secondary piston being provided with a channel for placing the secondary supply and pressure chambers in communication closable by a valve;
• FIG. 1 shows a tandem master cylinder for an electro-hydraulic braking system, according to a first embodiment of the invention, designated by the general reference 10.
• the tandem master cylinder 10 is of the type with valves.
• an organ is qualified as “proximal” when it is close to the brake pedal actuated by the driver, by considering the kinematic chain connecting this organ to the brake pedal, and “distal” in the case opposite.
• the master cylinder 10 comprises a body 12 delimiting two chambers for pressurizing brake fluid, usually called primary pressure chambers 14 and secondary 16.
• the body 12 also defines a chamber 18 for supplying the secondary pressure chamber 16.
• This room 18, usually called room secondary supply, is connected to a brake fluid reservoir (not shown) using conventional means 19.
• the master cylinder 10 also comprises two primary 20 and secondary 22 pistons.
• the primary piston 20 is connected, in a manner known per se, to a brake pedal (not shown) intended to be actuated by the driver.
• the secondary piston 22 separates the primary 14 and secondary 16 pressure chambers.
• the two pistons 20, 22 carry primary 24 and secondary 26 conventional valves.
• the master cylinder 10 also comprises conventional means 28 for hydraulic connection of the primary pressure chamber to conventional means 30 for simulating braking force.
• the hydraulic connection means 28 can be closed off using an O-ring 32, carried by the secondary piston 22, intended to cooperate with an annular support seat 34 formed in the body 12.
• the O-ring 32 and the seat support 34 respectively form mobile and fixed complementary means for closing the connection means 28.
• the secondary piston 22 can be moved axially, parallel to the axis X shown in FIG. 1, between a rest position, in which the O-ring 32 and support seat 34 are spaced from one another, and a cooperation position of these O-rings 32 and support seat 34 in which the connection means 28 are closed.
• the secondary piston 22 has two proximal 22P and distal 22B parts which can be moved axially relative to each other to adjust the relative axial position of the O-ring 32 and the support seat 34 when this secondary piston 22 is in its position. rest illustrated in FIG. 1.
• the proximal part 22P of the secondary piston comprises a threaded male member M intended to cooperate by screwing with a female member F threaded from the distal part 22D of the secondary piston.
• the male member M forming a screw, is intended to cooperate with the female member F, forming a nut, to connect the two proximal 22P and distal 22D parts of the secondary piston.
• a lock nut 36 is intended to be screwed onto the male member M, bearing against the female member F, to immobilize these male members M and female F in a predetermined relative position.
• the proximal part 22P of the secondary piston has a transverse slot 38 intended to receive a conventional tool for operating this proximal part.
• the proximal part 22P of the secondary piston carries the O-ring 32.
• the distal part 22D of the secondary piston is intended to cooperate with a pin 40, integral with the body 12, forming a rest stop defining the rest position of the secondary piston 22.
• the pin 40 extends substantially transversely to the direction of movement of the secondary piston 22 in an oblong housing 42 formed in the distal part 22D of this piston.
• the oblong housing 42 is in communication with the secondary supply chamber 18.
• the latter can be placed in communication with the secondary pressure chamber 16 via a channel 44 which can be closed off by means of the secondary valve 26.
• the secondary valve 26 is provided with a control tail 46, extending through the channel 44, intended to cooperate with the pin 40 so as to maintain the valve 26 in the open position, when the secondary piston 22 is in its position rest, as illustrated in Figure 1.
• the secondary piston 22 is returned elastically to its rest position by a spring 48, called the secondary spring.
• stroke dead C To adjust the stroke of the secondary piston 22 between its rest position, as shown in Figure 1, and the closed position of the connection means 28 (cooperation of the O-ring 32 with the support seat 34), called stroke dead C, we can proceed as follows.
• the secondary piston 22 is in its rest position as shown in Figure 1.
• the primary piston 20 is not yet mounted in the body 12 of the master cylinder.
• the primary pressure chamber 14 is supplied with a pressurized gas, in particular air, and there is a pressure sensor in the means 30 for simulating braking force.
• a displacement sensor makes it possible to measure the displacements of the secondary piston 22.
• connection means 28 being open, the pressurized air contained in the primary pressure chamber 14 flows into the force simulation means 30.
• the secondary piston 22 is then moved against the elastic return force of the spring 48 until the connection means 28 are closed by cooperation of the O-ring 32 with the support seat 34. This closure is detected by the pressure sensor which detects a pressure variation in the force simulation means 30.
• the dead travel C is determined using the displacement detector of the secondary piston 22.
• the dead travel C is brought to the desired value by screwing or unscrewing the proximal part 22P of the secondary piston in the distal part 22D of this piston.
• FIG. 2 a tandem master cylinder for electrohydrauiic braking system according to a second embodiment of the invention.
• the elements similar to those of FIG. 1 are designated by identical references.
• the proximal part 22P of the secondary piston has a generally tubular shape closed at its distal end.
• the proximal part 22P of the secondary piston therefore delimits an internal housing allowing the introduction of a tool for maneuvering and / or radial deformation of this proximal part 22P.
• the two proximal 22P and distal 22D parts are immobilized relative to each other. by radially deforming at least one of the screwing surfaces of the male M and female F organs.

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• Engineering & Computer Science (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Transmission Of Braking Force In Braking Systems (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=8867472

Family Applications (1)

Country Status (5)

Families Citing this family (4)

Family Cites Families (1)

• 2001
  • 2001-09-20 FR FR0112164A patent/FR2829737B1/fr not_active Expired - Fee Related
• 2002
  • 2002-09-10 US US10/490,188 patent/US6959547B2/en not_active Expired - Fee Related
  • 2002-09-10 WO PCT/FR2002/003066 patent/WO2003024757A1/fr not_active Application Discontinuation
  • 2002-09-10 JP JP2003528430A patent/JP2005502535A/ja not_active Withdrawn
  • 2002-09-10 EP EP02777412A patent/EP1429944A1/de not_active Withdrawn

Non-Patent Citations (1)

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