EP1420990A1 - Valve booster - Google Patents

Valve booster

Info

Publication number
EP1420990A1
EP1420990A1 EP02774860A EP02774860A EP1420990A1 EP 1420990 A1 EP1420990 A1 EP 1420990A1 EP 02774860 A EP02774860 A EP 02774860A EP 02774860 A EP02774860 A EP 02774860A EP 1420990 A1 EP1420990 A1 EP 1420990A1
Authority
EP
European Patent Office
Prior art keywords
piston
lever
control rod
valve
rear chamber
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Withdrawn
Application number
EP02774860A
Other languages
German (de)
French (fr)
Inventor
Bruno Beylerian
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1420990A1 publication Critical patent/EP1420990A1/en
Withdrawn legal-status Critical Current

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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
    • B60T13/24—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 gaseous
    • B60T13/46—Vacuum systems
    • B60T13/52—Vacuum systems indirect, i.e. vacuum booster units
    • B60T13/57—Vacuum systems indirect, i.e. vacuum booster units characterised by constructional features of control valves

Definitions

  • the present invention relates, in general, to the technical field of braking systems for motor vehicles.
  • the invention relates to a servo brake assist tire comprising: a rigid casing; a movable partition sealingly delimiting a front chamber and a rear chamber inside the rigid envelope, the front chamber being connected in operational position to a pressure source delivering a first pressure, and the rear chamber being selectively connected to the front chamber or subjected to a controlled pressure by selective communication with a second pressure higher than the 'first; a pneumatic piston moving with the movable partition; a control rod adopting in the piston, a relative position depending at least on an actuating force selectively applied to the control rod in an axial actuation direction oriented towards the front chamber, and on an opposing restoring force oriented in an axial return direction; a plunger housed in the piston and driven by the control rod; a three-way valve controlling the pressure in the rear chamber, this valve connecting - selectively the rear chamber to the front chamber, or to the second pressure, depending on whether the control rod adopts with respect to the piston a relative position of rest under the
  • the present invention aims to provide a servomotor distinguished from known servomotors, in terms of its performance or its size, at least either by a reduced dead stroke, or by a time of shorter response, either by a reduced difference between the attack force and the return force, or by a restricted diameter of the piston tail, and possibly by several of these parameters.
  • the booster according to the invention is essentially characterized in that the valve comprises a lever mounted tilting relative to the control rod and having on either side of the control rod the first and second lever arms -respectively terminated by first and second ends, first and second valve seats defined in the piston, first and second valves articulated on the first and second respective ends of the lever and being applied selectively to the first and second respective seats by relative movements respectively oriented in the axial direction of actuation and in the axial direction of return, a first communication path connecting the rear and front chambers through the first valve seat, a second communication path connecting the rear chamber second pressure through the second valve seat, a spring biasing at least the first lever arm in the axial return direction, and a stop stopping the movement - • of the first lever arm in the axial return direction to the rest position of the control rod -
  • the valves are articulated on the lever by means of respective rods, and the stop is formed
  • the previously mentioned spring may consist of a helical spring constrained in compression and disposed between the piston and the lever.
  • the piston may have a piston tail passing in leaktight manner through an opening made in the casing, for the control rod to be integral with a sleeve having two ends by which this sleeve is slidably mounted in the piston tail, that a ring is pivotally mounted on a median external surface of the sleeve, and that the two lever arms of the lever are fixed to the ring and pass through Respective axial ports, made in the piston tail and arranged in the rear chamber.
  • the ring is for example formed of two halves of rings threaded on pivots projecting from the median external surface of the sleeve, and joined to one another by means of two connections by which the lever arms are fixed to the ring.
  • FIG. 1 is an axial sectional view of a known booster, shown with the master cylinder which it allows to actuate;
  • Figure 2 is a partial schematic axial sectional view of a booster according to the invention, shown in the rest position;
  • Figure 3 is a partial schematic axial sectional view of the booster of Figure 2, -represented in the actuation phase;
  • Figure 4 is a partial schematic axial sectional view of the booster of Figure 2, shown in the return phase;
  • - Figure 5 is a partial cross-sectional view of a particular embodiment of a booster according to the invention, the section being made in the plane of the lever; and
  • FIG. 6 is a partial axial section view of the booster illustrated in FIG. 5, this booster being observed according to the incidence defined by the arrows VI-VI of FIG. 5.
  • the invention relates to a pneumatic brake booster.
  • a pneumatic brake booster essentially comprises a rigid casing 1, a movable partition 2, a front chamber 3, a rear chamber 4, a pneumatic piston 5, a control rod 7, a plunger 8, a three-way valve 9, and a reaction member 13, for example a rubber reaction disc.
  • the front 3 and rear 4 chambers are delimited in a sealed manner, inside the rigid envelope 1, by the movable partition 2, these chambers therefore having respective variable and complementary volumes.
  • the control rod 7 is slidably mounted in the piston 5, and adopts with respect to this piston a position which depends in particular on an actuation force Fe which can be applied to the control rod 7 in an axial actuation direction X +, and an opposing return force Fr, exerted by a spring 98, and oriented in an axial return direction
  • the plunger 8 which is housed in the piston 5, is driven by the control rod 7 and controls the three-way valve 9, the latter controlling the pressure in the rear chamber 4.
  • valve 9 connects the rear chamber 4 either to the front chamber 3 or to the second pressure Pa, depending on whether the control rod 7 adopts relative to the piston 5 a relative position of rest under the effect of the force Fr, or an actuation position under the effect of the actuation force
  • the front chamber 3 When the booster is placed in its operational environment, the front chamber 3 is permanently connected to a source of pneumatic vacuum, such as the intake inlet of a heat engine or a vacuum pump, delivering a low pressure Pd.
  • a source of pneumatic vacuum such as the intake inlet of a heat engine or a vacuum pump, delivering a low pressure Pd.
  • the rear chamber 4 When the booster is at rest, the rear chamber 4 is connected to the front chamber 3, and therefore subjected to the vacuum Pd which prevails in the front chamber.
  • the rear chamber 4 When the servomotor is actuated by application of the actuating force Fe, the rear chamber 4 is subjected to a pressure controlled by communication with a second pressure Pa greater than the first Pd, for example with the atmosphere, the difference between the pressures Pa and Pd then making it possible to reveal an assistance force Fa, which is exerted on the movable partition 2, and which is applied to the disc 13 by the pneumatic piston 5, which moves with the movable partition 2.
  • the valve 9 essentially comprises a lever 90, two valve seats 51 and 52, two valves 61 and 62, two communication channels 11 and 12, a spring 93, and a stop 611.
  • the lever 90 is mounted tilting relative to the control rod 7 and has, on either side of the control rod, identical and opposite lever arms 91 and 92, the ends of which form the ends 901 and 902 of the lever 90.
  • the valves 61 and 62 are articulated on the respective ends 901 and 902 of the lever 90 and can be applied to the respective seats 51 and 52, which are both formed in the pneumatic piston 5.
  • valve 61 can be applied to the seat 51 by a movement oriented in the axial direction of actuation X +, while the valve
  • the communication path 11 connects the rear 4 and front 3 chambers through the valve seat 51, while the communication path 12 connects the rear chamber 4 at the second pressure Pa through the second valve seat 52.
  • the function of the spring 93 is to urge the lever arm 91 in the axial return direction X-, this spring being for example constituted by a helical spring constrained in compression and disposed between the piston 5 and the lever 90.
  • the stop 611 has the function of stopping the movement of the lever arm 91 in the axial return direction X- for the rest position of the control rod 7.
  • FIGS. 2 to 4 The operation of the booster of the invention is illustrated in FIGS. 2 to 4.
  • the spring 98 pushes the piston 5 in the return direction X- -
  • the lever arm 91 blocked by the stopper 611, pushes the valve 61 against the seat 51, the arm 'of lever 92 symmetrically pulling the valve 62 toward the seat 52.
  • a force for actuating Fe is exerted on the rod 7 (FIG. 3)
  • this rod moves in the piston 5 in the direction of actuation X +.
  • the communication channel 12 is then open, and the atmospheric air, available outside the rigid envelope 1, is admitted into the rear chamber 4 through this second communication channel.
  • this relative displacement of the rod 7 relative to the piston 5 produces the application of the valve 62 on the valve seat 52, the communication channel 12 being thus cut, and the rear chamber 4 being therefore isolated atmospheric air.
  • the communication channel 11 is then open, and the rear chamber 4 is subjected to the pressure Pd prevailing in the front chamber 3.
  • the restoring force Fr exerted by the spring 98 makes it possible to return the piston 5 to its rest position by moving it in the return direction X-.
  • valves 61, 62 are for example articulated on the lever 90 by means of respective rods 610 and 620.
  • the stop 611 can then for example be formed by an extension of the rod 610 of the valve 61, which comes into contact with the rigid casing 1 for the rest position of the control rod 7.
  • FIGS. 5 and 6 An example of a practical embodiment of the invention is illustrated by FIGS. 5 and 6, in the traditional case -where the piston 5 has a piston tail 50 slidably mounted sealingly in an opening 10 made in the rigid casing .
  • control rod 7 is integral with a hollow sleeve 14, which is slidably mounted in a sealed manner in the piston tail 50 by its two ends 141 and 142. Between its ends 141 and 142, the sleeve 14 has a median external surface 140 which is essentially cylindrical, continuous, of restricted diameter, and from which two pivots, 143 and 144, project mutually aligned in the median plane of the sleeve 14 and turned opposite one another.
  • the halves of rings 151 and 152 are joined together to the other by means of respective links 16 and 17, by which the lever arms 91 and 92 of the lever 90 are respectively fixed to the ring 15.
  • lever arms 91 and 92 pass through respective axial slots 501 and 502, which are formed in the piston tail 50 and which are arranged in the rear chamber 4.
  • the seal provided between each of the ends 141 and 142 of the sleeve 14 and the internal surface of the piston tail 50 makes it possible to obtain that the only possible communication channel between the rear chamber 4 and the atmosphere Pa is that which constitutes the communication channel 12 which passes between the seat 52 and the valve 62.

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Braking Systems And Boosters (AREA)

Abstract

The invention relates to a pneumatic brake booster comprising, in particular, a rigid casing (1), a mobile partition (2), a front chamber (3) which is subjected to a vacuum (Pd), a rear chamber (4) which is subjected, as required, to a vacuum or to atmospheric pressure (Pa), a pneumatic piston (5), a control rod (7), a plunger (8), a three-way check valve (9) and a reaction disk (13). According to the invention, the check valve (9) essentially comprises two valves (61, 62). Said valves are articulated to a lever (90), which is mounted to tilt in relation to the control rod (7), and come into contact with the respective seats (51, 52) therefor by means of reverse movements. One of said valves (61) controls a communication passage (11) that links the rear chamber (4) and the front chamber (3) and the other valve (62) controls a communication passage (12) that links the rear chamber (4) with the atmospheric pressure (Pa).

Description

SERVOMOTEUR A SOUPAPES VALVE SERVOMOTOR
La présente invention concerne, de façon générale, le domaine technique des systèmes de freinage pour véhicules automobiles.The present invention relates, in general, to the technical field of braking systems for motor vehicles.
Plus précisément', l'invention concerne un servomoteur pneumatique d'assistance au freinage comprenant : une enveloppe rigide ; une cloison mobile délimitant de façon étanche une chambre avant et une chambre arrière à l'intérieur de l'enveloppe rigide, la chambre avant étant reliée en situation opérationnelle à une source de pression délivrant une première pression, et la chambre arrière étant sélectivement reliée à la chambre avant ou soumise à une pression contrôlée par mise en communication sélective avec une seconde pression supérieure à la ' première; un piston pneumatique se déplaçant avec la cloison mobile; une tige de commande adoptant dans le piston, une position relative dépendant au moins d'une force d' actionnement sélectivement appliquée sur la tige de commande suivant une direction axiale d' actionnement orientée vers la chambre avant, et d'une force de rappel antagoniste orientée suivant une direction axiale de retour; un plongeur logé dans le piston et entraîné par la tige de commande; un clapet à trois voies contrôlant la pression dans la chambre arrière, ce clapet reliant - sélectivement la chambre arrière à la chambre avant, ou à la seconde pression, selon que la tige de commande adopte par rapport au piston une position relative de repos sous l'effet au moins de la force de rappel, ou une position relative d' actionnement sous l'effet de la force d' actionnement ; et un organe de réaction recevant et transmettant la force d' actionnement appliquée par le plongeur et une force d'assistance appliquée par le piston et provenant d'un effort exercé par la pression contrôlée sur la cloison mobile. Bien que des dispositifs de ce type soient connus et utilisés avec succès depuis des décennies, ils continuent de faire l'objet de nombreuses recherches visant à en optimiser les performances. La présente invention, qui s'inscrit totalement dans ce contexte, a pour but de proposer un servomoteur se distinguant des servomoteurs connus, au plan de ses performances ou de son encombrement, au moins soit par une course morte réduite, soit par un temps de réponse plus court, soit par une différence réduite entre l'effort d'attaque et l'effort de retour, soit par un diamètre restreint de la queue de piston, et éventuellement par plusieurs de ces paramètres .Specifically ', the invention relates to a servo brake assist tire comprising: a rigid casing; a movable partition sealingly delimiting a front chamber and a rear chamber inside the rigid envelope, the front chamber being connected in operational position to a pressure source delivering a first pressure, and the rear chamber being selectively connected to the front chamber or subjected to a controlled pressure by selective communication with a second pressure higher than the 'first; a pneumatic piston moving with the movable partition; a control rod adopting in the piston, a relative position depending at least on an actuating force selectively applied to the control rod in an axial actuation direction oriented towards the front chamber, and on an opposing restoring force oriented in an axial return direction; a plunger housed in the piston and driven by the control rod; a three-way valve controlling the pressure in the rear chamber, this valve connecting - selectively the rear chamber to the front chamber, or to the second pressure, depending on whether the control rod adopts with respect to the piston a relative position of rest under the 'effect at least of the restoring force, or a relative position of actuation under the effect of the actuating force; and a reaction member receiving and transmitting the actuating force applied by the plunger and an assistance force applied by the piston and coming from a force exerted by the controlled pressure on the movable partition. Although devices of this type have been known and successfully used for decades, they continue to be the subject of much research aimed at optimizing their performance. The present invention, which is fully in this context, aims to provide a servomotor distinguished from known servomotors, in terms of its performance or its size, at least either by a reduced dead stroke, or by a time of shorter response, either by a reduced difference between the attack force and the return force, or by a restricted diameter of the piston tail, and possibly by several of these parameters.
A cette fin, le servomoteur selon l'invention, par ailleurs conforme à la définition générique qui en est donnée dans le préambule ci-dessus, est essentiellement caractérisé en ce que le clapet comprend un levier monté basculant par rapport à la tige de commande et présentant de part et d'autre de la tige de commande des premier et second bras de levier -respectivement terminés par des première et seconde extrémités, des premier et second sièges de soupape définis dans le piston, des première et seconde soupapes articulées sur les première et seconde extrémités respectives du levier et s 'appliquant sélectivement sur les premier et second sièges respectifs par des mouvements relatifs respectivement orientés suivant la direction axiale d' actionnement et suivant la direction axiale de retour, une première voie de communication reliant les chambres arrière et avant à travers le premier siège de soupape, une seconde voie de communication reliant la chambre arrière à la seconde pression à travers le second siège de soupape, un ressort sollicitant au moins le premier bras de levier dans la direction axiale de retour, et une butée arrêtant le mouvement -• du premier bras de levier dans la direction axiale de retour pour la position de repos de la tige de commande - Dans un mode de réalisation possible de l'invention, les soupapes sont articulées sur le levier au moyen de tiges respectives, et la butée est formée par un prolongement de la tige de la première soupape venant en contact avec l'enveloppe rigide pour la position de repos de la tige de commande.To this end, the booster according to the invention, moreover conforms to the generic definition which is given in the preamble above, is essentially characterized in that the valve comprises a lever mounted tilting relative to the control rod and having on either side of the control rod the first and second lever arms -respectively terminated by first and second ends, first and second valve seats defined in the piston, first and second valves articulated on the first and second respective ends of the lever and being applied selectively to the first and second respective seats by relative movements respectively oriented in the axial direction of actuation and in the axial direction of return, a first communication path connecting the rear and front chambers through the first valve seat, a second communication path connecting the rear chamber second pressure through the second valve seat, a spring biasing at least the first lever arm in the axial return direction, and a stop stopping the movement - • of the first lever arm in the axial return direction to the rest position of the control rod - In a possible embodiment of the invention, the valves are articulated on the lever by means of respective rods, and the stop is formed by an extension of the rod of the first valve coming into contact with the rigid casing for the position rest of the control rod.
Le ressort précédemment mentionné, peut quant à lui être constitué par un ressort hélicoïdal contraint en compression et disposé entre le piston et le levier. Pour assurer 1 ' étanchéité requise de la chambre arrière, il est possible de prévoir que le piston présente une queue- de piston traversant de façon étanche une ouverture pratiquée dans l'enveloppe, que la tige de commande soit solidaire d'un manchon présentant deux extrémités par lesquelles ce manchon est monté coulissant de façon étanche dans la queue de piston, qu'un anneau soit monté pivotant sur une surface externe médiane du manchon, et que les deux bras de levier du levier soient fixés à 1 ' anneau et traversent des lumières axiales respectives, pratiquées dans la queue de piston et disposées dans la chambre arrière.The previously mentioned spring, for its part, may consist of a helical spring constrained in compression and disposed between the piston and the lever. To ensure the required tightness of the rear chamber, it is possible to provide for the piston to have a piston tail passing in leaktight manner through an opening made in the casing, for the control rod to be integral with a sleeve having two ends by which this sleeve is slidably mounted in the piston tail, that a ring is pivotally mounted on a median external surface of the sleeve, and that the two lever arms of the lever are fixed to the ring and pass through Respective axial ports, made in the piston tail and arranged in the rear chamber.
En outre, pour permettre le montage de l'ensemble, l'anneau est par exemple formé de deux moitiés d'anneaux enfilées sur des pivots saillant de la surface externe médiane du manchon, et réunies l'une à l'autre au moyen de deux liaisons par lesquelles les bras de levier sont fixés à l'anneau.In addition, to allow the assembly of the assembly, the ring is for example formed of two halves of rings threaded on pivots projecting from the median external surface of the sleeve, and joined to one another by means of two connections by which the lever arms are fixed to the ring.
D'autres caractéristiques et avantages de l'invention ressortiront clairement de la description qui en est faite ci-après, à titre indicatif et nullement limitatif, en référence aux dessins annexés, dans lesquels :Other characteristics and advantages of the invention will emerge clearly from the description given below, by way of indication and in no way limitative, with reference to the appended drawings, in which:
- la Figure 1 est une vue en coupe axiale d'un servomoteur connu, représenté avec le maître-cylindre qu'il permet d'actionner; la Figure 2 est une vue en coupe axiale schématique partielle d'un servomoteur conforme à l'invention, représenté en position de repos; la Figure 3 est une vue en coupe axiale schématique partielle du servomoteur de la figure 2, -représenté en phase d' actionnement ; la Figure 4 est une vue en coupe axiale schématique partielle du servomoteur de la figure 2, représenté en phase de retour; - la Figure 5 est une vue en coupe transversale partielle d'un mode particulier de réalisation d'un servomoteur conforme à l'invention, la coupe étant réalisée dans le plan du levier; et- Figure 1 is an axial sectional view of a known booster, shown with the master cylinder which it allows to actuate; Figure 2 is a partial schematic axial sectional view of a booster according to the invention, shown in the rest position; Figure 3 is a partial schematic axial sectional view of the booster of Figure 2, -represented in the actuation phase; Figure 4 is a partial schematic axial sectional view of the booster of Figure 2, shown in the return phase; - Figure 5 is a partial cross-sectional view of a particular embodiment of a booster according to the invention, the section being made in the plane of the lever; and
- la Figure 6 est une vue en coupe axiale partielle du servomoteur illustré à la figure 5, ce servomoteur étant observé suivant l'incidence définie par les flèches VI-VI de la figure 5.FIG. 6 is a partial axial section view of the booster illustrated in FIG. 5, this booster being observed according to the incidence defined by the arrows VI-VI of FIG. 5.
Comme annoncé précédemment, l'invention concerne un servomoteur pneumatique d'assistance au freinage. De façon traditionnelle, et comme le montre la figure 1, un tel servomoteur comprend essentiellement une enveloppe rigide 1, une cloison mobile 2, une chambre avant 3, une chambre arrière 4, un piston pneumatique 5, une tige de commande 7, un plongeur 8, un clapet à trois voies 9, et un organe de réaction 13, par exemple un disque de réaction en caoutchouc.As previously announced, the invention relates to a pneumatic brake booster. Traditionally, and as shown in FIG. 1, such a booster essentially comprises a rigid casing 1, a movable partition 2, a front chamber 3, a rear chamber 4, a pneumatic piston 5, a control rod 7, a plunger 8, a three-way valve 9, and a reaction member 13, for example a rubber reaction disc.
Les chambres avant 3 et arrière 4 sont délimitées de façon étanche, à l'intérieur de l'enveloppe rigide 1, par la cloison mobile 2, ces chambres ayant donc des volumes respectifs variables et complémentaires.The front 3 and rear 4 chambers are delimited in a sealed manner, inside the rigid envelope 1, by the movable partition 2, these chambers therefore having respective variable and complementary volumes.
La tige de commande 7 est montée coulissante dans le piston 5, et adopte par rapport à ce piston une position qui dépend notamment d'une force d' actionnement Fe qui peut être appliquée sur la tige de commande 7 suivant une direction axiale d ' actionnement X+, et d'une force de rappel Fr antagoniste, exercée par un ressort 98, et orientée suivant une direction axiale de retourThe control rod 7 is slidably mounted in the piston 5, and adopts with respect to this piston a position which depends in particular on an actuation force Fe which can be applied to the control rod 7 in an axial actuation direction X +, and an opposing return force Fr, exerted by a spring 98, and oriented in an axial return direction
X-.X-.
Le plongeur 8, qui est logé dans le piston 5, est entraîné par la tige de commande 7 et commande le clapet à trois voies 9, ce dernier contrôlant la pression dans la chambre arrière 4.The plunger 8, which is housed in the piston 5, is driven by the control rod 7 and controls the three-way valve 9, the latter controlling the pressure in the rear chamber 4.
Plus précisément, le clapet 9 relie la chambre arrière 4 soit à la chambre avant 3 , soit à la seconde pression Pa, selon que la tige de commande 7 adopte par rapport au piston 5 une position relative de repos sous l'effet de la force de rappel Fr, ou une position d' actionnement sous l'effet de la force d' actionnementMore specifically, the valve 9 connects the rear chamber 4 either to the front chamber 3 or to the second pressure Pa, depending on whether the control rod 7 adopts relative to the piston 5 a relative position of rest under the effect of the force Fr, or an actuation position under the effect of the actuation force
Fe.Fe.
Lorsque le servomoteur est placé dans son environnement opérationnel, la chambre avant 3 est reliée en permanence à une source de dépression pneumatique, telle que l'entrée d'admission d'un moteur thermique ou une pompe à vide, délivrant une basse pression Pd.When the booster is placed in its operational environment, the front chamber 3 is permanently connected to a source of pneumatic vacuum, such as the intake inlet of a heat engine or a vacuum pump, delivering a low pressure Pd.
Lorsque le servomoteur est au repos, la chambre arrière 4 est reliée à la chambre avant 3, et donc soumise à la dépression Pd qui règne dans la chambre avant .When the booster is at rest, the rear chamber 4 is connected to the front chamber 3, and therefore subjected to the vacuum Pd which prevails in the front chamber.
Lorsque le servomoteur est actionné par application de la force d' actionnement Fe, la chambre arrière 4 est soumise à une pression contrôlée par mise en communication avec une seconde pression Pa supérieure à la première Pd, par exemple avec l'atmosphère, la différence entre les pressions Pa et Pd permettant alors de faire apparaître une force d'assistance Fa, qui s'exerce sur la cloison mobile 2, et qui est appliquée sur le disque 13 par le piston pneumatique 5, qui se déplace avec la cloison mobile 2.When the servomotor is actuated by application of the actuating force Fe, the rear chamber 4 is subjected to a pressure controlled by communication with a second pressure Pa greater than the first Pd, for example with the atmosphere, the difference between the pressures Pa and Pd then making it possible to reveal an assistance force Fa, which is exerted on the movable partition 2, and which is applied to the disc 13 by the pneumatic piston 5, which moves with the movable partition 2.
Enfin, le disque de réaction 13 reçoit et transmet à une tige de poussée 99 la force d ' actionnement Fe qui appliquée par le plongeur 8 et la force d'assistance Fa qui est exercée par le piston 5. Selon l'invention, le clapet 9 comprend essentiellement un levier 90, deux sièges de soupape 51 et 52, deux soupapes 61 et 62, deux voies de communication 11 et 12, un ressort 93, et une butée 611. Le levier 90 est monté basculant par rapport à la tige de commande 7 et présente, de part et d'autre de la tige de commande, des bras de levier identiques et opposés 91 et 92, dont les extrémités forment les extrémités 901 et 902 du levier 90. Les soupapes 61 et 62 sont articulées sur les extrémités respectives 901 et 902 du levier 90 et peuvent s'appliquer sur les sièges respectifs 51 et 52, qui sont tous deux formés dans le piston pneumatique 5.Finally, the reaction disc 13 receives and transmits to an push rod 99 the actuating force Fe which applied by the plunger 8 and the assistance force Fa which is exerted by the piston 5. According to the invention, the valve 9 essentially comprises a lever 90, two valve seats 51 and 52, two valves 61 and 62, two communication channels 11 and 12, a spring 93, and a stop 611. The lever 90 is mounted tilting relative to the control rod 7 and has, on either side of the control rod, identical and opposite lever arms 91 and 92, the ends of which form the ends 901 and 902 of the lever 90. The valves 61 and 62 are articulated on the respective ends 901 and 902 of the lever 90 and can be applied to the respective seats 51 and 52, which are both formed in the pneumatic piston 5.
Plus précisément, ,1a soupape 61 peut s'appliquer sur le siège 51 par un mouvement orienté suivant la direction axiale d' actionnement X+, tandis que la soupapeMore precisely, the valve 61 can be applied to the seat 51 by a movement oriented in the axial direction of actuation X +, while the valve
62 peut s'appliquer sur le siège 52 par un mouvement orienté suivant la direction axiale de retour X- .62 can be applied to the seat 52 by a movement oriented in the axial return direction X-.
Par ailleurs, la voie de communication 11 relie les chambres arrière 4 et avant 3 à travers le siège de soupape 51, tandis que la voie de communication 12 relie la chambre arrière 4 à la seconde pression Pa à travers le second siège de soupape 52.Furthermore, the communication path 11 connects the rear 4 and front 3 chambers through the valve seat 51, while the communication path 12 connects the rear chamber 4 at the second pressure Pa through the second valve seat 52.
Le ressort 93 a pour fonction de solliciter le bras de levier 91 dans la direction axiale de retour X-, ce ressort étant par exemple constitué par un ressort hélicoïdal contraint en compression et disposé entre le piston 5 et le levier 90.The function of the spring 93 is to urge the lever arm 91 in the axial return direction X-, this spring being for example constituted by a helical spring constrained in compression and disposed between the piston 5 and the lever 90.
La butée 611 a quant à elle pour fonction d'arrêter le mouvement du bras de levier 91 dans la direction axiale de retour X- pour la position de repos de la tige de commande 7.The stop 611 has the function of stopping the movement of the lever arm 91 in the axial return direction X- for the rest position of the control rod 7.
Le fonctionnement du servomoteur de l'invention est illustré par les figures 2 à 4. Lorsque le servomoteur est au repos (figure 2) , le ressort 98 repousse le piston 5 dans la direction de retour X- - Le bras de levier 91, bloqué par la butée 611, pousse la soupape 61 contre le siège 51, le bras' de levier 92 tirant symétriquement la soupape 62 vers le siège 52. Lorsqu'une force d' actionnement Fe est exercée sur la tige de commande 7 (figure 3) , cette tige se déplace dans le piston 5 dans la direction d' actionnement X+ .The operation of the booster of the invention is illustrated in FIGS. 2 to 4. When the booster is at rest (FIG. 2), the spring 98 pushes the piston 5 in the return direction X- - The lever arm 91, blocked by the stopper 611, pushes the valve 61 against the seat 51, the arm 'of lever 92 symmetrically pulling the valve 62 toward the seat 52. When a force for actuating Fe is exerted on the rod 7 (FIG. 3), this rod moves in the piston 5 in the direction of actuation X +.
Mais comme la soupape 61 est déjà en • appui sur le siège 51, le mouvement relatif de la tige 7 et du piston 5 n'est possible que dans la mesure où le levier 90 bascule par rapport à la tige, ce qui a pour effet que le bras de levier 92 dégage la soupape 62 de son siège 52.But as the valve 61 is already • rests on the seat 51, the relative movement of the rod 7 and the piston 5 is possible only insofar as the lever 90 rocking relative to the shaft, which has the effect that the lever arm 92 releases the valve 62 from its seat 52.
La voie de communication 12 est alors ouverte, et l'air atmosphérique, disponible à l'extérieur de l'enveloppe rigide 1, est admis dans la chambre arrière 4 à travers cette seconde voie de communication.The communication channel 12 is then open, and the atmospheric air, available outside the rigid envelope 1, is admitted into the rear chamber 4 through this second communication channel.
Lorsque la force d' actionnement Fe disparaît (figure 4), la tige de commande 7, sollicitée par la force qu'exerce le ressort 93, se déplace dans la direction de retour X- par rapport au piston 5.When the actuating force Fe disappears (FIG. 4), the control rod 7, stressed by the force exerted by the spring 93, moves in the return direction X- relative to the piston 5.
Dans - un premier temps, ce déplacement relatif de la tige 7 par rapport au piston 5 produit l'application de la soupape 62 sur le siège de clapet 52, la voie de communication 12 étant ainsi coupée, et la chambre arrière 4 étant donc isolée de l'air atmosphérique.In a first step, this relative displacement of the rod 7 relative to the piston 5 produces the application of the valve 62 on the valve seat 52, the communication channel 12 being thus cut, and the rear chamber 4 being therefore isolated atmospheric air.
Dès la fermeture du siège de clapet 52 par la soupape 62, le mouvement relatif ultérieur de la tige 7 par rapport au piston 5 sous l'effet de la force exercée par le ressort 93 provoque, dans un deuxième temps, un basculement du levier 90 par rapport à la tige 7 dans un sens tel que le bras de levier 91 dégage la soupape 61 de son siège 51.As soon as the valve seat 52 is closed by the valve 62, the subsequent relative movement of the rod 7 relative to the piston 5 under the effect of the force exerted by the spring 93 causes, in a second step, a tilting of the lever 90 with respect to the rod 7 in a direction such that the lever arm 91 releases the valve 61 from its seat 51.
La voie de communication 11 est alors ouverte, et la chambre arrière 4 est soumise à la pression Pd régnant dans la chambre avant 3. Enfin, la force de rappel Fr exercée par le ressort 98 permet de ramener le piston 5 dans sa position de repos en le déplaçant dans la direction de retour X- .The communication channel 11 is then open, and the rear chamber 4 is subjected to the pressure Pd prevailing in the front chamber 3. Finally, the restoring force Fr exerted by the spring 98 makes it possible to return the piston 5 to its rest position by moving it in the return direction X-.
Comme le montrent les figures 2 à 4, les soupapes 61, 62 sont par exemple articulées sur le levier 90 au moyen de tiges respectives 610 et 620.As shown in Figures 2 to 4, the valves 61, 62 are for example articulated on the lever 90 by means of respective rods 610 and 620.
La butée 611 peut alors par exemple être formée par un prolongement de la tige 610 de la soupape 61, qui vient en contact avec l'enveloppe rigide 1 pour la position de repos de la tige de commande 7.The stop 611 can then for example be formed by an extension of the rod 610 of the valve 61, which comes into contact with the rigid casing 1 for the rest position of the control rod 7.
Un exemple de mode de réalisation pratique de l'invention est illustré par les figures 5 et 6, dans le cas traditionnel -où le piston 5 présente une queue de piston 50 montée coulissante de façon étanche dans une ouverture 10 pratiquée dans l'enveloppe rigide .An example of a practical embodiment of the invention is illustrated by FIGS. 5 and 6, in the traditional case -where the piston 5 has a piston tail 50 slidably mounted sealingly in an opening 10 made in the rigid casing .
Selon ce mode de réalisation, la tige de commande 7 est solidaire d'un manchon creux 14, qui est monté coulissant de façon étanche dans la queue de piston 50 par ses deux extrémités 141 et 142. Entre ses extrémités 141 et 142, le manchon 14 présente une surface externe médiane 140 essentiellement cylindrique, continue, de diamètre restreint, et dont font saillie deux pivots, 143 et 144, mutuellement alignés dans le plan médian du manchon 14 et tournés à l'opposé l'un de l'autre.According to this embodiment, the control rod 7 is integral with a hollow sleeve 14, which is slidably mounted in a sealed manner in the piston tail 50 by its two ends 141 and 142. Between its ends 141 and 142, the sleeve 14 has a median external surface 140 which is essentially cylindrical, continuous, of restricted diameter, and from which two pivots, 143 and 144, project mutually aligned in the median plane of the sleeve 14 and turned opposite one another.
Un anneau 15, formé de deux moitiés d'anneaux 151 et 152 respectivement enfilées sur les pivots 143 et 144, est monté pivotant sur la • surface externe médiane 140 du manchon 14. Les moitiés d'anneaux 151 et 152 sont réunies l'une à l'autre au moyen de liaisons respectives 16 et 17, grâce auxquelles les bras de levier 91 et 92 du levier 90 se trouvent respectivement fixés à l'anneau 15.A ring 15, formed of two halves of rings 151 and 152 respectively threaded on the pivots 143 and 144, is pivotally mounted on the • median external surface 140 of the sleeve 14. The halves of rings 151 and 152 are joined together to the other by means of respective links 16 and 17, by which the lever arms 91 and 92 of the lever 90 are respectively fixed to the ring 15.
Enfin, ces bras de levier 91 et 92 traversent des lumières axiales respectives 501 et 502, qui sont pratiquées dans la queue de piston 50 et qui sont disposées dans la chambre arrière 4. Ainsi, malgré l'existence des lumières 501 et 502 pratiquées dans la queue de piston 50, l'étanchéité assurée entre chacune des extrémités 141 et 142 du manchon 14 et la surface interne de la queue de piston 50 permet d'obtenir que la seule voie de communication possible entre la chambre arrière 4 et l'atmosphère Pa soit celle que constitue la voie de communication 12 qui passe entre le siège 52 et la soupape 62. Finally, these lever arms 91 and 92 pass through respective axial slots 501 and 502, which are formed in the piston tail 50 and which are arranged in the rear chamber 4. Thus, despite the existence of the lights 501 and 502 made in the piston tail 50, the seal provided between each of the ends 141 and 142 of the sleeve 14 and the internal surface of the piston tail 50 makes it possible to obtain that the only possible communication channel between the rear chamber 4 and the atmosphere Pa is that which constitutes the communication channel 12 which passes between the seat 52 and the valve 62.

Claims

REVENDICATIONS
1. Servomoteur pneumatique d'assistance au freinage comprenant : une enveloppe rigide (1) ; une cloison mobile1. Pneumatic brake booster comprising: a rigid casing (1); a movable partition
(2) délimitant de façon étanche une chambre avant (3) et une chambre arrière (4) à l'intérieur de l'enveloppe rigide (1) , la chambre avant (3) étant reliée en situation opérationnelle à une source de pression délivrant une première pression (Pd) , et la chambre arrière (4) étant sélectivement reliée à la chambre avant(2) sealingly delimiting a front chamber (3) and a rear chamber (4) inside the rigid envelope (1), the front chamber (3) being operatively connected to a pressure source delivering a first press (Pd), and the rear chamber (4) being selectively connected to the front chamber
(3) ou soumise à une pression contrôlée par mise en communication sélective avec une seconde pression (Pa) supérieure à la première (Pd) ; un piston pneumatique (5) se déplaçant avec la cloison mobile (2) ; une tige de commande (7) adoptant dans le piston (5) une position relative dépendant au moins d'une force d' actionnement (Fe) sélectivement appliquée sur la tige de commande (7) suivant une direction axiale d' actionnement (X+) orientée vers la chambre avant (3), et d'une force de rappel (Fr) antagoniste orientée suivant une direction axiale de retour (X-); un plongeur (8) logé dans le piston (5) et entraîné par la tige de commande (7) ; un clapet à trois voies (9) contrôlant la pression dans la chambre arrière (4) , ce clapet reliant sélectivement la chambre arrière(3) or subjected to a pressure controlled by selective communication with a second pressure (Pa) greater than the first (Pd); a pneumatic piston (5) moving with the movable partition (2); a control rod (7) adopting in the piston (5) a relative position depending at least on an actuating force (Fe) selectively applied to the control rod (7) in an axial actuation direction (X +) oriented towards the front chamber (3), and of an opposing restoring force (Fr) oriented in an axial return direction (X-); a plunger (8) housed in the piston (5) and driven by the control rod (7); a three-way valve (9) controlling the pressure in the rear chamber (4), this valve selectively connecting the rear chamber
(4) à la chambre avant (3), ou à la seconde pression (Pa) , selon que la tige de commande (7) adopte par rapport au piston (5) une position relative de repos sous l'effet au moins de la force de rappel (Fr) , ou une position relative d' actionnement sous l'effet de la force d' actionnement (Fe) ; et un organe de réaction (13) recevant et transmettant la force d' actionnement (Fe) appliquée par le plongeur (8) et une force d'assistance (Fa) appliquée par le piston (5) et provenant d'un effort exercé par la pression contrôlée sur la cloison mobile (2) , caractérisé en ce que le clapet (9) comprend un levier (90) monté basculant par rapport à la tige de commande (7) et présentant de part et d'autre de la tige de commande des premier et second bras de levier (91, 92) respectivement terminés par des première et seconde extrémités (901, 902) du levier, des premier et second sièges de soupape (51, 52) définis dans le piston (5) , des première et seconde soupapes (61, 62) articulées sur les première et seconde extrémités respectives (901, 902) du levier (90) et s 'appliquant sélectivement sur les premier et second sièges respectifs (51, 52) par des mouvements relatifs respectivement orientés suivant la direction axiale d' actionnement (X+) et suivant la direction axiale de retour (X-), une première voie de communication (11) reliant les chambres arrière (4) et avant (3) à travers le premier siège (51) de soupape, une seconde voie de communication (12) reliant la chambre arrière (4) à la seconde pression (Pa) à travers le second siège de soupape (52), un ressort (93) sollicitant au moins le premier bras de levier (91) dans la direction axiale de retour (X-) , et une butée (611) arrêtant le mouvement du premier bras de levier (91) dans la direction axiale de retour (X-) pour la position de repos de la tige de commande (7) .(4) to the front chamber (3), or to the second pressure (Pa), depending on whether the control rod (7) adopts relative to the piston (5) a relative position of rest under the effect at least of the restoring force (Fr), or a relative actuation position under the effect of the actuation force (Fe); and a reaction member (13) receiving and transmitting the actuating force (Fe) applied by the plunger (8) and an assistance force (Fa) applied by the piston (5) and coming from a force exerted by the pressure controlled on the movable partition (2), characterized in that the valve (9) comprises a lever (90) mounted to tilt relative to the rod control (7) and having on either side of the control rod the first and second lever arms (91, 92) respectively terminated by first and second ends (901, 902) of the lever, the first and second seats valve (51, 52) defined in the piston (5), first and second valves (61, 62) articulated on the respective first and second ends (901, 902) of the lever (90) and being applied selectively on the first and second respective seats (51, 52) by relative movements respectively oriented in the axial direction of actuation (X +) and in the axial direction of return (X-), a first communication channel (11) connecting the rear chambers (4) and front (3) through the first valve seat (51), a second communication channel (12) connecting the rear chamber (4) to the second pressure (Pa) through the second valve seat (52 ), a spring (93) urging at least the first lever arm (91) in the axial return direction (X-), and a stop (611) stopping the movement of the first lever arm (91) in the axial return direction (X-) for the rest position of the control rod (7 ).
2. Servomoteur suivant la revendication 1, caractérisé en ce que les soupapes (61, 62) sont articulées sur le levier (90) au moyen de tiges respectives (610, 620) , et en ce que la butée (611) est formée par un prolongement de la tige (610) de la première soupape (61) venant en contact avec l'enveloppe rigide (1) pour la position de repos de la tige de commande (7) .2. Booster according to claim 1, characterized in that the valves (61, 62) are articulated on the lever (90) by means of respective rods (610, 620), and in that the stop (611) is formed by an extension of the rod (610) of the first valve (61) coming into contact with the rigid casing (1) for the rest position of the control rod (7).
3. Servomoteur suivant la revendication 1 ou 2 , caractérisé en ce que le ressort (93) est un ressort hélicoïdal contraint en compression et disposé entre le piston (5) et le levier (90) . 3. Booster according to claim 1 or 2, characterized in that the spring (93) is a helical spring constrained in compression and disposed between the piston (5) and the lever (90).
4. Servomoteur suivant l'une quelconque des revendications précédentes, caractérisé en ce que le piston (5) présente une queue de piston (50) traversant de façon étanche une ouverture (10) pratiquée dans l'enveloppe, en ce que la tige de commande (7) est solidaire d'un manchon (14) présentant deux extrémités (141, 142) par lesquelles ce manchon (14) est monté coulissant de façon étanche dans la queue de piston (50) , en ce qu'un anneau (15) est monté pivotant sur une surface externe médiane (140) du manchon (14) , et en ce que les deux bras de levier (91, 92) du levier (90) sont fixés à l'anneau (15) et traversent des lumières axiales respectives (501, 502), pratiquées dans la queue de piston (50) et disposées dans la chambre arrière (4) .4. Booster according to any one of the preceding claims, characterized in that the piston (5) has a piston rod (50) passing through sealingly an opening (10) formed in the envelope, in that the control rod (7) is integral with a sleeve (14) having two ends (141, 142) by which this sleeve (14) is mounted sliding in a sealed manner in the piston tail (50), in that a ring (15) is pivotally mounted on a median external surface (140) of the sleeve (14), and in that the two lever arms (91 , 92) of the lever (90) are fixed to the ring (15) and pass through respective axial slots (501, 502), formed in the piston tail (50) and arranged in the rear chamber (4).
5. Servomoteur suivant la revendication 4, caractérisé en ce que l'anneau (15) est formé de deux moitiés d'anneaux (151, 152) enfilées sur des pivots (143, 144) saillant de la surface externe médiane (140) du manchon (14), et réunies l'une à l'autre au moyen de deux liaisons (16, 17) par lesquelles les bras de levier (91, 92) sont fixés à l'anneau (15). 5. Booster according to claim 4, characterized in that the ring (15) is formed of two halves of rings (151, 152) threaded on pivots (143, 144) projecting from the median external surface (140) of the sleeve (14), and joined to each other by means of two connections (16, 17) by which the lever arms (91, 92) are fixed to the ring (15).
EP02774860A 2001-08-08 2002-07-30 Valve booster Withdrawn EP1420990A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR0110617 2001-08-08
FR0110617A FR2828467B1 (en) 2001-08-08 2001-08-08 VALVE SERVOMOTOR
PCT/FR2002/002727 WO2003013928A1 (en) 2001-08-08 2002-07-30 Valve booster

Publications (1)

Publication Number Publication Date
EP1420990A1 true EP1420990A1 (en) 2004-05-26

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ID=8866395

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02774860A Withdrawn EP1420990A1 (en) 2001-08-08 2002-07-30 Valve booster

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Country Link
US (1) US20040195912A1 (en)
EP (1) EP1420990A1 (en)
JP (1) JP2004537468A (en)
FR (1) FR2828467B1 (en)
WO (1) WO2003013928A1 (en)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1879892A (en) * 1927-12-21 1932-09-27 Dewandre Albert Fluid braking mechanism
DE3908805A1 (en) * 1989-03-17 1990-09-20 Teves Gmbh Alfred BRAKE POWER AMPLIFIER

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO03013928A1 *

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WO2003013928A1 (en) 2003-02-20
FR2828467B1 (en) 2003-10-24
JP2004537468A (en) 2004-12-16
US20040195912A1 (en) 2004-10-07
FR2828467A1 (en) 2003-02-14

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