WO2001089901A1 - Brake servo unit comprising a bushing adjustable by deformation, and assembly for adjusting the bushing - Google Patents

Brake servo unit comprising a bushing adjustable by deformation, and assembly for adjusting the bushing Download PDF

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Publication number
WO2001089901A1
WO2001089901A1 PCT/EP2001/006459 EP0106459W WO0189901A1 WO 2001089901 A1 WO2001089901 A1 WO 2001089901A1 EP 0106459 W EP0106459 W EP 0106459W WO 0189901 A1 WO0189901 A1 WO 0189901A1
Authority
WO
WIPO (PCT)
Prior art keywords
sleeve
control rod
face
transverse
section
Prior art date
Application number
PCT/EP2001/006459
Other languages
French (fr)
Inventor
Joan Simon Bacardit
Fernando Sacristan
Original Assignee
Bosch Sistemas De Frenado, S.L.
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 Bosch Sistemas De Frenado, S.L. filed Critical Bosch Sistemas De Frenado, S.L.
Priority to PL01359000A priority Critical patent/PL359000A1/en
Priority to MXPA02012187A priority patent/MXPA02012187A/en
Priority to JP2001586107A priority patent/JP2003534198A/en
Priority to EP01955302A priority patent/EP1289817A1/en
Priority to AU77504/01A priority patent/AU774150B2/en
Priority to BR0111337-2A priority patent/BR0111337A/en
Publication of WO2001089901A1 publication Critical patent/WO2001089901A1/en

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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
    • B60T13/569—Vacuum systems indirect, i.e. vacuum booster units characterised by piston details, e.g. construction, mounting of diaphragm

Definitions

  • the invention relates to a pneumatic brake booster for a motor vehicle.
  • the invention relates more particularly to a pneumatic brake booster for a motor vehicle, of the type which comprises a rigid envelope inside which is movable a transverse partition sealingly delimiting a front chamber, subjected to a first pressure of engine depression, and a rear chamber subjected to a second pressure varying between engine depression and atmospheric pressure, of the type which comprises a movable piston secured to the movable partition moving with the movable partition and a control rod moving in the piston selectively as a function of an axial input force exerted towards the front against a return force exerted on the rod by a return spring, of the type in which the rod is movable in an intermediate actuation position or an extreme actuation position obtained when the input force is applied at a determined high speed, from the type which comprises a plunger which is arranged at the front of the control rod in the piston and a three-way valve which comprises at least one annular rear seat of the plunger and which
  • a conventional servomotor has neither a probe nor a one-way clutch device for the probe.
  • the plunger is likely to come to directly solicit the reaction disc secured to the rear face of the mobile piston.
  • the actuation of the control rod causes the actuation of the plunger also forming a feeler, which causes the maximum opening of the valve at three tracks so that the rear chamber is brought to atmospheric pressure. There follows a displacement towards the front of the movable partition and the end of the plunger comes into contact with the reaction disc secured to the rear face of the movable piston.
  • the force exerted on the mobile piston when the control rod is at the end of the race results from the assistance force which is caused by the pressure difference on each side of the mobile wall and from the force exerted by the plunger forming a probe on said movable piston.
  • the driver of the vehicle also feels the braking reaction force, which is transmitted from the movable piston to the plunger via the reaction disc.
  • the plunger can come into contact with the reaction disc and transmit to the driver a feeling of maximum braking even before the difference in pressure is maximum between the front and rear pressure chambers, which can lead the driver to relax his effort, even if he should be maintained to benefit from the maximum braking effort.
  • a servomotor such as that of the type described above overcomes this drawback by blocking the probe in contact with the reaction disc by immobilizing the sleeve and therefore maintaining maximum force on the rear face of the movable piston even if the driver would have partially relaxed his effort.
  • a unidirectional clutch device for such a servomotor is moreover of a substantially reduced manufacturing cost since it comprises a feeler integrated into the socket.
  • the booster of the type described above has the drawback of requiring compliance with precise manufacturing dimensions for the socket.
  • the sleeve comprising the probe is mounted so that a determined clearance is established between the probe and the reaction disc in the rest position.
  • the value of this play determines the assistance force supplied by the mobile piston for which a reaction force is transmitted, via the reaction disk, from the mobile piston to the control rod.
  • the value of this assistance effort is commonly called the "jump" of the servomotor, and it is therefore dependent on the dimensions of the probe, in particular the thickness of the probe.
  • the axial position of the blocking element of the bush determines the speed for which the one-way clutch device may trip.
  • This speed is commonly known as the "tripping speed”, and it is therefore dependent on dimensions of the sleeve, in particular on the axial distance separating the front end of the plunger from the blocking element of the sleeve.
  • the blocking element of the sleeve is produced in the form of a transverse shoulder face, which makes it possible to obtain a sleeve capable of being suitable for the correct operation of the servomotor by producing it by a machining process. , including filming. The dimensional dimensions are then obtained by the turning process.
  • the invention provides a socket, the dimensions of which can be adjusted simply by a plastic deformation process.
  • the invention provides a servomotor of the type described above, characterized in that the socket has a first adjustment part, arranged between the front and rear faces of the probe, and a second adjustment part, arranged between the rear face. of the feeler and the locking element, which are plastically deformable, at least in the axial direction, so as to allow the actuator to be adjusted before it is assembled.
  • the locking element is formed by a substantially annular key which loosely surrounds the socket and which is capable, when the input force is applied at the determined speed, of being driven by the movable piston to tilt around a generally transverse axis so that a lug of the key comes into abutment against a rear transverse face of the socket forming the blocking element,
  • the bushing comprises a tubular front cylindrical section, the end of which forms the feeler and a tubular rear cylindrical section, of a diameter substantially greater than the diameter of the front section which comprises a radial groove, a transverse front face of shoulder of which forms the rear transverse blocking face,
  • the front section includes an inner annular flange which extends rearwardly, projecting from the rear face of the probe, and which is capable of being deformed axially before assembly to constitute the first adjustment part making it possible to adjust the position, or jump of the servomotor, in which the probe requests the reaction disc, - the front section and the rear section of the sleeve are separated by an intermediate section of reduced thickness which is capable of being deformed axially to constitute the second adjustment part making it possible to adjust the trigger position according to which the lug of the key is received in abutment against the rear transverse locking face,
  • the groove has a substantially frustoconical profile behind the front transverse shoulder face
  • the lug has the shape of a concave frustoconical angular sector which is complementary to the frustoconical profile of the groove of the sleeve,
  • the key has, in section through an axial plane, the shape of a "T" whose vertical branch of substantially radial orientation is crossed by the sleeve and whose horizontal branch, of substantially axial orientation is received without axial play Between two opposite walls of a recess which crosses the piston perpendicularly to its axis to allow only a tilting of the key in the recess.
  • the front horizontal half-branch of the T-shaped wrench has a face facing radially towards the bushing from which the lug protrudes
  • the T-key is elastically recalled against the rear transverse wall of the recess by two compression springs arranged between the front transverse wall of the recess and blind holes for centering the T-key which are arranged on the side and other side of the socket in the vertical branch of the T,
  • the sleeve is made of a material having a reduced elastic limit and a high toughness.
  • the invention also provides an assembly for the plastic deformation of a tubular sleeve of a pneumatic brake booster of the type described above which comprises, from front to back, a cylindrical front tubular section with a determined external diameter. , which is closed at its end by a front transverse wall from which extends towards the inside of the bushing a deformable annular coaxial flange forming a first adjustment part, a deformable intermediate section of the same outside diameter as the front section forming a second adjustment part, and a rear cylindrical section of a determined diameter greater than the diameter of the front section comprising at least one rear transverse shoulder face.
  • the invention provides an assembly of the type described above, characterized in that it comprises a male matrix and a coaxial tubular female matrix between which the sleeve is interposed to be deformed during a single deformation operation by axial compression by pressing the dies axially against each other to obtain simultaneously determined dimensions of the first and second setting part.
  • the internal diameter of the tubular female matrix is greater than the external diameter of the rear section of the sleeve, and the female matrix has a rear transverse wall from which extends a cylindrical bearing on which the sleeve is threaded forwards. so that a front end of the cylindrical seat bears against the annular collar of the sleeve,
  • the male matrix has a bore with a diameter corresponding to the outside diameter of the front section of the bushing, a front transverse bottom of which is intended to allow the front transverse wall of the front section of the bushing to be supported,
  • the male matrix comprises a convex cylindrical bearing surface which projects rearwards and which is intended to receive a first tubular shim of determined length adjustment arranged in the extension of the female tubular matrix
  • the assembly comprises a tubular spacer before d support intended to be threaded on the sleeve in axial contact with the transverse shoulder face of the sleeve and a second rear tubular shim of fixed length adjustment which are intended to be placed in the female matrix between the cylindrical seat of the female matrix and its internal cylindrical wall prior to the deformation operation by axial compression
  • the male matrix is fixed, and the female matrix is slidably mounted axially to be pressed towards the male matrix with a compression force of determined intensity.
  • FIG. 1 is an overall view of a booster produced in accordance with the state of the art
  • FIG. 2 is a view in axial section of detail of a pneumatic brake booster according to the invention shown in the inactive position of the one-way clutch,
  • FIG. 3 is a view in axial section of detail of a pneumatic brake booster according to the invention shown in the active position of the one-way clutch,
  • FIG. 4 is a view in axial section of a socket for a one-way clutch according to FIGS. 1 or 2, and,
  • FIG. 5 is an axial sectional view of an assembly for the plastic deformation of a sleeve according to Figure 3.
  • identical reference numerals denote identical parts or having similar functions.
  • front By convention, the terms “front”, “rear”, upper “,” lower “respectively designate elements or positions oriented respectively to the left, the right, the top, or the bottom of FIGS. 1 to 5.
  • FIG. 1 shows a set of a pneumatic brake booster 1 0 for a motor vehicle.
  • the pneumatic servomotor 10 comprises a rigid casing 12 inside which is mounted a movable transverse partition 14 which delimitably a front chamber 16, subjected to a first pressure "Pi” whose value is equal to the value of the depression of the vehicle engine, and a rear chamber 18 subjected to a second pressure "P 2 ".
  • the second pressure "P 2 " is likely, as will be described later, to vary between the value of engine vacuum “Pi” and the value of atmospheric pressure "P a ".
  • the front chamber 16 is supplied with pressure "Pt" via a vacuum conduit 20 which is connected to a source of vacuum in the vehicle, for example a vacuum prevailing in an intake manifold (not shown) of a vehicle engine.
  • the pneumatic booster 10 comprises a movable piston 22 which is integral with the movable partition 14. Inside the casing 12, the movable partition 14 is biased elastically towards the rear by a return spring 24 which bears on the envelope 12 and on a front face 26 of the movable piston 22.
  • the front face 26 of the movable piston 22 carries a reaction cup 30 inside which is arranged, as will be seen below, a reaction disc 32 in elastomeric material.
  • a front face 34 of the reaction cup 30 is integral with an actuating rod 28, which is consequently integral with the displacements of the movable piston 22, and which allows the actuation of a hydraulic master cylinder 36 for braking the vehicle.
  • a control rod 38 which is for example connected to a brake pedal of the vehicle by means of a coupling sleeve 41 which is arranged at its rear free end 43, is capable of moving in the movable piston 22 , selectively as a function of an axial input force exerted forward on the control rod 38.
  • the actuating force is exerted against a return force which is exerted on the rod 38 by a return spring 40 which is interposed between the movable piston 22 and the control rod 38.
  • the other front end of the control rod 38 is shaped as a ball joint 42 and is received in a complementary housing 44 of a substantially cylindrical plunger 46 which is slidably mounted in the movable piston 22.
  • a rear annular seat 48 of the plunger 46 is part of a three-way valve 50 which is capable of varying the second pressure "P 2 " prevailing in the rear chamber 18, in particular by connecting the front chamber 16 and the rear chamber 18 when the control rod 38 is in the rest position, or by gradually bringing the rear chamber 18 into communication with the atmospheric pressure "P a " when the control rod 38 is activated.
  • a feeler 52 is formed at the front end of a socket 58 which is slidably mounted on the front end of the plunger 46 which is opposite to the housing 44.
  • the front end of the socket 58 forming the feeler 52 is also slidably mounted inside a bore 54 of the movable piston
  • the servomotor 10 comprises a one-way clutch device 56 which comprises on the one hand a locking element forming part of the coaxial socket 58 and which on the other hand comprises a movable locking element which is formed of a substantially annular key 60 surrounding the bush 58 with radial clearance.
  • the coaxial sleeve is slidably mounted on the plunger 46 and is resiliently returned by the intermediary of a spring 57, interposed between the piston 22 and the sleeve 58, in contact with a front transverse face 59 of the plunger 46 .
  • the socket 58 passes through a circular lumen 61 of the key 60.
  • the key 60 is disposed in a recess 62 which crosses the piston 22 perpendicular to its axis "A".
  • the key 60 is resiliently biased against a rear wall 66 of the recess 62.
  • a lower part 70 of the key 60 is, in the rest position shown in FIG. 2, supported on a support 72 which is linked to the casing 12 of the booster 10.
  • a transverse pin 71 which crosses transversely the socket 58 and the plunger 46, is, in the rest position of the rod 38, bearing on a front face of the key 60 to define the rest position of the plunger 46.
  • the plunger 46 drives the sleeve 58 at a speed which is higher than that of the movable piston 22.
  • An upper part 64 of the key 60 is then driven by the control piston 22 while its lower part 70 leaves its support on the support 72.
  • the key 60 does not being more supported on the socket 58, it rocks around a generally transverse axis and counterclockwise to cooperate with a blocking element of the periphery of the socket 58, in particular a rear transverse face 76 of the socket .
  • the unidirectional clutch device 56 has been shown in the figures as comprising a locking element consisting of the key 60 previously described, but it will be understood that it may also include a movable locking element of another type, which is capable of immobilizing axially precisely the rear transverse face 76 of the socket 58.
  • the servomotor 10 which is the subject of the invention, which will now be described more specifically with reference to FIGS. 2 and 3, comprises a one-way clutch 56 whose key 60 includes a lug 78 which is intended, in the active position of the clutch , to come into abutment against the rear transverse face 76 of the socket 58 forming the blocking element for blocking the socket 58 according to a precise axial position.
  • the socket 58 comprises a tubular front cylindrical section 79, the end of which forms the feeler 52, and a tubular rear cylindrical section 83, with a diameter substantially greater than the diameter of the front section, which has a radial groove 80, a front transverse shoulder face forms the rear transverse face 76 for locking.
  • the radial groove 80 delimits in the rear section 83 a front cylindrical surface 81 and a rear cylindrical surface 85.
  • the groove 80 has a substantially frustoconical profile behind the front transverse face 76 of the shoulder. In this way, the end of the groove 80 which is opposite the face front transverse shoulder 76 progressively joins the cylindrical periphery of the rear section 83 of the socket 58.
  • the frustoconical profile of the groove 80 of the socket 58 is particularly advantageous because it allows, during the tilting of the key 60, to guide the lug 78 of the key, which has the shape of a concave frustoconical angular sector complementary to the profile frustoconical of the groove 80, to its stop position against the front shoulder face 76 of the socket 58.
  • the circular opening 61 of the key 60 which surrounds the socket 58, does not participate in blocking the socket 58. The latter is entirely ensured by the lug 78.
  • the key 60 has, in section through an axial plane, the general shape of a "T" whose vertical branch 82 of substantially radial orientation includes the lumen 61 which is crossed by the socket 58.
  • the key 60 in "T” has a horizontal branch 84, which is of substantially axial orientation perpendicular to the main branch 82, and which is received without axial play between the front walls 68 and rear 66 of the recess 62 which crosses the piston 22 perpendicularly to its axis "A".
  • This configuration has the advantage of allowing only a tilting movement of the key 60 in the recess 62.
  • the key 60 is not capable of moving axially relative to the recess 62, but can see its branch 82 tilt in the recess 62, in accordance with FIG. 3.
  • the lug 78 is arranged under the horizontal branch 84 of the key 60 in "T". More particularly, the horizontal horizontal half-branch 86 of the T-shaped key has a face facing radially towards the socket 58 from which the lug 78 projects.
  • the key 60 in "T” is resiliently returned to meet the transverse wall 66 of the recess by two compression springs 94 and 95 which are arranged between the transverse wall before 68 of the recess 62 and the blind 96 holes for centering the key 60 in T which are arranged on either side of the sleeve in the vertical branch 82 of the T.
  • the mobile piston 22 moves substantially at the same speed as the plunger 46, because the establishment of the pressure atmospheric "P a " takes place as the three-way valve 50 opens.
  • the horizontal branch 84 being maintained between the front 68 and rear 66 walls of the recess 62 without the possibility of axial displacement, the key 60 switches as soon as the vertical branch 82 of the key leaves its lower support on the support 72 integral with the casing 12.
  • the lug 68 then comes into contact with the socket 58 on the front surface 81 of the rear section 83, but does not instantaneously enter the frustoconical groove 80 since the socket 58 and the movable piston 22 move at roughly the same speed.
  • the key 60 does not block the socket 58 and does not oppose the return from front to back of the movable piston 22.
  • the plunger 46 advances faster than the movable piston 22 can do, due to the delay linked to the balancing of the pressure in the rear chamber 18.
  • the lug 78 leaves the front bearing 81, falls into the groove 80, and slides into abutment up to the face 76 shoulder to precisely lock the bush 58 axially.
  • the key 60 blocks the socket 58 and therefore the probe 52, thus opposing the return of the movable piston 22 from front to back, regardless of the position of the plunger 46. This position maintains maximum braking force on piston 22.
  • the socket 58 comprising the feeler 52 is mounted so that a determined clearance "J 1", shown in FIG. 2, is established in the rest position, between the feeler 52 and the reaction disc 32.
  • this clearance "J 1" determines the assistance force supplied by the mobile piston 22 for which a reaction force is transmitted, via the reaction disk 32, from the mobile piston 22 to the control rod 38.
  • the value of this assistance effort is called “jump" of the servomotor 10, and it depends on the dimensions of the probe 52, in particular on the axial thickness "H 1" of the probe 5 shown in FIG. 4.
  • the axial position of the rear transverse face 76 forming the locking element of the socket 58 conditions the speed at which the clutch device unidirectional 58 is likely to trip. Indeed, as long as the lug 78 of the key 60 is capable of being retained by the front bearing 81 of the rear section 83, it does not fall into the groove 80, and the one-way clutch device 56 remains inactive.
  • This speed is commonly known under the name of "tripping speed”, and is therefore dependent, as shown in FIG. 4, on the dimensions of the sleeve, in particular on the axial distance "H2" which separates a rear face 100 of the probe, which is arranged at the bottom of the bore 102 of the socket 58 and on which the front transverse end 59 of the plunger 46 is in support during its movement from back to front, of the transverse shoulder face 76 of the socket 58.
  • the socket 58 is obtained by a turning process in order to produce precisely the dimensional dimensions H 1 and H2 capable of being suitable for the correct operation of the servomotor 10.
  • This design has the drawback of considerably increasing the cost price of the socket because it requires respecting precise dimensions during the manufacture of the socket 58, and requires a unitary check of the socket 58.
  • the invention provides a socket 58, the dimensions of which can be adjusted simply by a plastic deformation process.
  • the socket 58 comprises a first adjustment part, arranged between the front and rear faces of the probe 52, and a second adjustment part, arranged between the rear face 100 of the probe 52 and the rear transverse face 76, which are plastically deformable at least in the axial direction so as to allow the actuator 10 to be adjusted before it is assembled.
  • the front section 79 includes an inner annular flange 104 which extends rearwardly, projecting from the rear face 100 of the probe 52, and which is capable of being deformed axially before assembly to constitute the first adjustment part making it possible to adjust the position, or jump of the servomotor 10, in which the probe 46 urges the reaction disc 32.
  • the front section 79 and the rear section 83 of the socket 58 are separated by an intermediate section 106 of reduced thickness "e" which is capable of being deformed axially to constitute the second adjustment part making it possible to adjust the release position according to which the lug 78 of the key 60 is received in abutment against the rear transverse blocking face 76.
  • the sleeve 58 is in particular made of a material comprising a reduced elastic limit and of great toughness, and it is deformed in a deformation assembly 108, represented in FIG. 5, which is specially intended for the deformation of the socket 58.
  • the assembly 108 comprises a male matrix 1 10 and a female tubular matrix 1 12 coaxial between which the sleeve 58 is interposed to be deformed during a single deformation operation by axial compression by pressing the dies 1 10 and 1 12 axially l 'one against the other to simultaneously obtain the determined dimensions "H 1" and H2 "of the first and second adjustment parts.
  • the internal diameter D h i 2 of the tubular female matrix 1 12 is greater than the external diameter D e83 of the rear section 83 of the socket 58, so as to allow reception of the socket 58 in the female matrix 1 12.
  • female matrix 1 12 has a rear transverse wall 1 14 from which extends a cylindrical seat 1 16 forwardly on which the sleeve 58 is threaded so that a front end 1 18 of the cylindrical seat 1 16 takes pressing against the annular flange 104 of the socket 58.
  • the male die 1 10 has a bore 120 with a diameter corresponding to the outside diameter D e 79 of the section front 79 of the socket 58.
  • a front transverse bottom 122 of the bore 120 is intended to allow the support of the front transverse wall 59 of the front section 79 of the socket 58.
  • the male die 1 10 has a convex cylindrical surface 124 which projects rearward and which is intended to receive a first tubular shim 126 for adjusting the length
  • the assembly 108 comprises a tubular spacer 128 before support which is intended to be threaded on the sleeve 58 in axial contact with the transverse shoulder face 76 of the sleeve 58 a second rear tubular wedge 130 for adjusting the length "L ⁇ 30 "determined which are intended to be placed in the female matrix 1 12 between the cylindrical surface 1 16 of the female matrix and its inner cylindrical wall 1 32 prior to the deformation operation by axial compression.
  • tubular shims 126 and 130 can be replaced, from one type of servomotor to another, to obtain values different from the dimensions "H 1" and "H2".
  • Ln 0 / ⁇ denotes the dimension of the matrix 1 10 which separates its front transverse bottom 122 from a shoulder 132 on which the first tubular wedge 126 comes to bear
  • Ln 2/1 denotes the dimension of the matrix 1 12 which separates its front end 1 34 on which the first tubular shim 126 comes to bear on the front end 1 18 of the cylindrical seat 1 16.
  • H2 Li 12/2 _ L-130 - Ll 28 (R2)
  • Ln 2/2 denotes the dimension of the matrix 1 12 which separates the front end 1 18 from its cylindrical seat 1 16 from the rear transverse wall 1 14, and in which L- ⁇ 2 8 denotes the length of the spacer.
  • H2 directly depend on the lengths of tubular shims 126 and 130. Typically, during the deformation operation, each of the initial dimensions H 1 or H2 is reduced from 0 to 0.5 mm.
  • the male die 1 10 is fixed, and the female die 1 12 is slidably mounted axially to be pressed towards the male die with a force F of determined intensity.
  • the orientation of the compressive force F and its point of application are shown in FIG. 5.
  • the invention therefore advantageously makes it possible to benefit from a booster 10 of a reduced cost making it possible to benefit from maximum braking force in emergency braking situations, whatever the behavior of the driver after violent braking.

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Braking Systems And Boosters (AREA)
  • Forging (AREA)
  • Braking Arrangements (AREA)
  • Actuator (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)

Abstract

The invention concerns a brake servo unit comprising a piston actuating a master-cylinder, including an elastic return control rod sliding in the piston in accordance with an input force, whereof the end bears a plunger carrying a sliding probe (52) capable of stressing a reaction disc of the actuating rod to transmit to the control rod the piston reaction, and comprising a one-way clutch release device comprising a key and a bushing (58) including the probe (52) which is mounted sliding on the plunger, and which can, when the control rod is actuated at a predetermined speed, lock the bushing (58) relative to the mobile piston independently of the control rod. The invention is characterised in that the bushing (58) comprises first and second adjusting parts (104, 106) plastically deformable in the axial direction to adjust beforehand the servo unit. The invention also concerns a deformation assembly to produce such a bushing (58).

Description

"Servomoteur comportant une douille réglable par déformation, et montage pour régler la douille" "Servomotor comprising a sleeve adjustable by deformation, and mounting for adjusting the sleeve"
L'invention concerne un servomoteur pneumatique d'assistance au freinage pour un véhicule automobile. L'invention concerne plus particulièrement un servomoteur pneumatique d'assistance au freinage pour un véhicule automobile, du type qui comporte une enveloppe rigide à l'intérieur de laquelle est mobile une cloison transversale délimitant de façon étanche une chambre avant, soumise à une première pression de dépression moteur, et une chambre arrière soumise à une deuxième pression variant entre la dépression moteur et la pression atmosphérique, du type qui comporte un piston mobile solidaire de la cloison mobile se déplaçant avec la cloison mobile et une tige de commande se déplaçant dans le piston sélectivement en fonction d'un effort axial d'entrée exercé vers l'avant à encontre d'un effort de rappel exercé sur la tige par un ressort de rappel, du type dans lequel la tige est mobile suivant une position d'actionnement intermédiaire ou une position d'actionnement extrême obtenue lorsque l'effort d'entrée est appliqué à une vitesse élevée déterminée, du type qui comporte un plongeur qui est agencé à l'avant de la tige de commande dans le piston et un clapet à trois voies qui comporte au moins un siège annulaire arrière du plongeur et qui est susceptible de faire varier la deuxième pression régnant dans la chambre arrière, notamment en mettant en communication la chambre avant et la chambre arrière lorsque la tige de commande est en position de repos ou en mettant progressivement la chambre arrière en communication avec la pression atmosphérique lorsque la tige de commande est actionnée, du type dans lequel, dans la position extrême d'actionnement de la tige de commande, une face arrière d'un palpeur monté coulissant à l'extrémité avant du plongeur est sollicitée par le plongeur de manière qu'une face avant du palpeur vienne au contact d'un disque de réaction solidaire du piston mobile pour transmettre au plongeur et à la tige de commande l'effort de réaction du piston mobile, et du type qui comporte un dispositif d'embrayage unidirectionnel qui comporte au moins une douille coaxiale tubulaire qui coulisse sur le plongeur et dont l'extrémité avant comporte le palpeur, et un élément de verrouillage qui est mobile entre une position active dans laquelle il ne coopère pas avec la douille et une positon active, commandée par la position extrême d'actionnement de la tige de commande, dans laquelle il coopère avec un élément de blocage de la douille pour la bloquer dans une position axiale avant extrême de manière que le palpeur bloque le piston mobile indépendamment du plongeur et de la tige de commande.The invention relates to a pneumatic brake booster for a motor vehicle. The invention relates more particularly to a pneumatic brake booster for a motor vehicle, of the type which comprises a rigid envelope inside which is movable a transverse partition sealingly delimiting a front chamber, subjected to a first pressure of engine depression, and a rear chamber subjected to a second pressure varying between engine depression and atmospheric pressure, of the type which comprises a movable piston secured to the movable partition moving with the movable partition and a control rod moving in the piston selectively as a function of an axial input force exerted towards the front against a return force exerted on the rod by a return spring, of the type in which the rod is movable in an intermediate actuation position or an extreme actuation position obtained when the input force is applied at a determined high speed, from the type which comprises a plunger which is arranged at the front of the control rod in the piston and a three-way valve which comprises at least one annular rear seat of the plunger and which is capable of varying the second pressure prevailing in the chamber rear, in particular by connecting the front chamber and the rear chamber when the control rod is in the rest position or by gradually bringing the rear chamber into communication with atmospheric pressure when the control rod is actuated, of the type in which, in the extreme actuation position of the control rod, a rear face of a probe mounted sliding at the front end of the plunger is urged by the plunger so that a front face of the probe comes into contact with a disc reaction integral with the movable piston to transmit to the plunger and the control rod the reaction force of the movable piston, and of the type which comprises a one-way clutch device which comprises at least one coaxial tubular sleeve which slides on the plunger and whose front end comprises the feeler, and a locking element which is movable between an active position in which it does not cooperate with the socket and an active position, controlled by the extreme actuation position of the control rod, in which it cooperates with a blocking element of the socket to block it in a extreme front axial position so that the probe blocks the movable piston independently of the plunger and the control rod.
De manière connue, une telle conception présente des avantages considérables en terme de sécurité lors d'une situation de freinage d'urgence. En effet, un servomoteur conventionnel ne comporte ni palpeur, ni dispositif d'embrayage unidirectionnel du palpeur. Le plongeur est susceptible de venir solliciter directement le disque de réaction solidaire de la face arrière du piston mobile.In known manner, such a design has considerable advantages in terms of safety during an emergency braking situation. In fact, a conventional servomotor has neither a probe nor a one-way clutch device for the probe. The plunger is likely to come to directly solicit the reaction disc secured to the rear face of the mobile piston.
Dans une situation de freinage extrême pour laquelle un effort de freinage maximal est exercé sur la tige de commande, l'actionnement de la tige du commande provoque l'actionnement du plongeur formant aussi palpeur, ce qui provoque l'ouverture maximale du clapet à trois voies de manière que la chambre arrière soit mise à la pression atmosphérique. Il s'ensuit un déplacement vers l'avant de la cloison mobile et l'extrémité du plongeur vient au contact du disque de réaction solidaire de la face arrière du piston mobile.In an extreme braking situation for which a maximum braking force is exerted on the control rod, the actuation of the control rod causes the actuation of the plunger also forming a feeler, which causes the maximum opening of the valve at three tracks so that the rear chamber is brought to atmospheric pressure. There follows a displacement towards the front of the movable partition and the end of the plunger comes into contact with the reaction disc secured to the rear face of the movable piston.
Ainsi, l'effort exercé sur le piston mobile lorsque la tige de commande est en fin de course résulte de l'effort d'assistance qui est provoqué par la différence de pression de chaque côté de la paroi mobile et de l'effort exercé par le plongeur formant palpeur sur ledit piston mobile. Le conducteur du véhicule ressent par ailleurs l'effort de réaction du freinage, qui est transmis du piston mobile au plongeur par l'intermédiaire du disque de réaction. Or, on a constaté que bon nombre de conducteurs, confrontés à une situation de freinage d'urgence, sous-estimaient les risques encourus, et que, après avoir freiné brutalement, ils relâchaient leur effort de freinage alors que le maintien d'un effort de freinage était indispensable pour éviter un accident.Thus, the force exerted on the mobile piston when the control rod is at the end of the race results from the assistance force which is caused by the pressure difference on each side of the mobile wall and from the force exerted by the plunger forming a probe on said movable piston. The driver of the vehicle also feels the braking reaction force, which is transmitted from the movable piston to the plunger via the reaction disc. However, it has been found that a good number of drivers, confronted with an emergency braking situation, underestimated the risks involved, and that, after braking suddenly, they released their braking effort while maintaining an effort braking was essential to avoid an accident.
En effet, dans le cas d'une situation de freinage extrême accompagnée d'un déplacement rapide de la tige de commande, le plongeur peut venir au contact du disque de réaction et transmettre au conducteur une sensation de freinage maximal avant même que la différence de pression ne soit maximale entre les chambres de pression avant et arrière, ce qui peut conduire le conducteur à relâcher son effort, quand bien même il devrait être maintenu pour bénéficier de l'effort de freinage maximal.Indeed, in the case of an extreme braking situation accompanied by a rapid displacement of the control rod, the plunger can come into contact with the reaction disc and transmit to the driver a feeling of maximum braking even before the difference in pressure is maximum between the front and rear pressure chambers, which can lead the driver to relax his effort, even if he should be maintained to benefit from the maximum braking effort.
U n servomoteur tel que celui du type décrit précédemment permet de remédier à cet inconvénient en bloquant le palpeur au contact du disque de réaction en immobilisant la douille et donc de maintenir un effort maximal sur la face arrière du piston mobile quand bien même le conducteur aurait partiellement relâché son effort. U n dispositif d'embrayage unidirectionnel pour un tel servomoteur est par ailleurs d'un coût de fabrication sensiblement réduit puisqu'il comporte un palpeur intégré à la douille.A servomotor such as that of the type described above overcomes this drawback by blocking the probe in contact with the reaction disc by immobilizing the sleeve and therefore maintaining maximum force on the rear face of the movable piston even if the driver would have partially relaxed his effort. A unidirectional clutch device for such a servomotor is moreover of a substantially reduced manufacturing cost since it comprises a feeler integrated into the socket.
Toutefois, le servomoteur du type décrit précédemment présente l'inconvénient de requérir le respect de cotes de fabrication précises pour la douille.However, the booster of the type described above has the drawback of requiring compliance with precise manufacturing dimensions for the socket.
En effet, dans un tel servomoteur, la douille comportant le palpeur est montée de manière que soit établi, en position de repos, un jeu déterminé entre le palpeur et le disque de réaction.In fact, in such a booster, the sleeve comprising the probe is mounted so that a determined clearance is established between the probe and the reaction disc in the rest position.
La valeur de ce jeu détermine l'effort d'assistance fourni par le piston mobile pour lequel un effort de réaction est transmis, par l'intermédiaire du disque de réaction, du piston mobile à la tige de commande. La valeur de cet effort d'assistance est communément appelée "saut" du servomoteur, et elle est donc dépendante des cotes du palpeur, notamment de l'épaisseur du palpeur.The value of this play determines the assistance force supplied by the mobile piston for which a reaction force is transmitted, via the reaction disk, from the mobile piston to the control rod. The value of this assistance effort is commonly called the "jump" of the servomotor, and it is therefore dependent on the dimensions of the probe, in particular the thickness of the probe.
Par ailleurs, dans un tel servomoteur, pour peu que l'effort d'entrée soit exercé à une vitesse supérieure à la vitesse déterminée sur la tige de commande, la position axiale de l'élément de blocage de la douille conditionne la vitesse pour laquelle le dispositif d'embrayage unidirectionnel est susceptible de se déclencher.Furthermore, in such a servomotor, provided that the input force is exerted at a speed greater than the speed determined on the control rod, the axial position of the blocking element of the bush determines the speed for which the one-way clutch device may trip.
Cette vitesse est communément connue sous le nom de "vitesse de déclenchement", et elle est donc dépendante de cotes de la douille, notamment de la distance axiale séparant l'extrémité avant du plongeur de l'élément de blocage de la douille.This speed is commonly known as the "tripping speed", and it is therefore dependent on dimensions of the sleeve, in particular on the axial distance separating the front end of the plunger from the blocking element of the sleeve.
Conventionnellement, l'élément de blocage de la douille est réalisé sous le forme d'une face transversale d'épaulement, ce qui permet d'obtenir une douille susceptible de convenir à un bon fonctionnement du servomoteur en la réalisant par un procédé d'usinage, notamment de tournage. Les cotes dimensionnelles sont alors obtenues par le procédé de tournage.Conventionally, the blocking element of the sleeve is produced in the form of a transverse shoulder face, which makes it possible to obtain a sleeve capable of being suitable for the correct operation of the servomotor by producing it by a machining process. , including filming. The dimensional dimensions are then obtained by the turning process.
Cette conception présente l'inconvénient de grever considérablement le prix de revient de la douille car elle nécessite de respecter des cotes précises.This design has the drawback of considerably increasing the cost price of the socket because it requires respecting precise dimensions.
Pour remédier à cet inconvénient, l'invention propose une douille dont les cotes peuvent être ajustées simplement par un procédé de déformation plastique. Dans ce but, l'invention propose un servomoteur du type décrit précédemment, caractérisé en ce que la douille comporte une première partie de réglage, agencée entre les faces avant et arrière du palpeur, et une deuxième partie de réglage, agencée entre la face arrière du palpeur et l'élément de blocage, qui sont déformables plastiquement, au moins suivant la direction axiale, de façon à permettre le réglage du servomoteur avant son assemblage.To overcome this drawback, the invention provides a socket, the dimensions of which can be adjusted simply by a plastic deformation process. To this end, the invention provides a servomotor of the type described above, characterized in that the socket has a first adjustment part, arranged between the front and rear faces of the probe, and a second adjustment part, arranged between the rear face. of the feeler and the locking element, which are plastically deformable, at least in the axial direction, so as to allow the actuator to be adjusted before it is assembled.
Selon d'autres caractéristiques de l'invention : l'élément de verrouillage est formé d'une clé sensiblement annulaire qui entoure avec jeu la douille et qui est susceptible, lorsque l'effort d'entrée est appliqué à la vitesse déterminée, d'être entraînée par le piston mobile pour basculer autour d'un axe globalement transversal de manière qu'un ergot de la clé vienne en butée contre une face transversale arrière de la douille formant l'élément de blocage,According to other characteristics of the invention: the locking element is formed by a substantially annular key which loosely surrounds the socket and which is capable, when the input force is applied at the determined speed, of being driven by the movable piston to tilt around a generally transverse axis so that a lug of the key comes into abutment against a rear transverse face of the socket forming the blocking element,
- la douille comporte un tronçon cylindrique avant tubulaire, dont l'extrémité forme le palpeur et un tronçon cylindrique arrière tubulaire, d'un diamètre sensiblement supérieur au diamètre du tronçon avant qui comporte une gorge radiale dont une face transversale avant d'épaulement forme la face transversale arrière de blocage,the bushing comprises a tubular front cylindrical section, the end of which forms the feeler and a tubular rear cylindrical section, of a diameter substantially greater than the diameter of the front section which comprises a radial groove, a transverse front face of shoulder of which forms the rear transverse blocking face,
- le tronçon avant comporte une collerette annulaire intérieure qui s'étend vers l'arrière, en saillie à partir de la face arrière du palpeur, et qui est susceptible d'être déformée axialement avant le montage pour constituer la première partie de réglage permettant de régler la position, ou saut du servomoteur, dans laquelle le palpeur sollicite le disque de réaction, - le tronçon avant et le tronçon arrière de la douille sont séparés par un tronçon intermédiaire d'épaisseur réduite qui est susceptible d'être déformé axialement pour constituer la deuxième partie de réglage permettant de régler la position de déclenchement selon laquelle l'ergot de la clé est reçu en butée contre la face transversale arrière de blocage,- The front section includes an inner annular flange which extends rearwardly, projecting from the rear face of the probe, and which is capable of being deformed axially before assembly to constitute the first adjustment part making it possible to adjust the position, or jump of the servomotor, in which the probe requests the reaction disc, - the front section and the rear section of the sleeve are separated by an intermediate section of reduced thickness which is capable of being deformed axially to constitute the second adjustment part making it possible to adjust the trigger position according to which the lug of the key is received in abutment against the rear transverse locking face,
- la gorge est d'un profil sensiblement tronconique en arrière de la face transversale avant d'épaulement,the groove has a substantially frustoconical profile behind the front transverse shoulder face,
- l'ergot présente la forme d'un secteur angulaire tronconique concave qui est complémentaire du profil tronconique de la gorge de la douille,the lug has the shape of a concave frustoconical angular sector which is complementary to the frustoconical profile of the groove of the sleeve,
- la clé présente, en section par un plan axial, la forme d'un "T" dont la branche verticale d'orientation sensiblement radiale est traversée par la douille et dont la branche horizontale, d'orientation sensiblement axiale est reçue sans jeu axial entre deux parois opposées d'un évidement qui traverse le piston perpendiculairement par rapport à son axe pour ne permettre qu'un basculement de la clé dans l'évidement.- The key has, in section through an axial plane, the shape of a "T" whose vertical branch of substantially radial orientation is crossed by the sleeve and whose horizontal branch, of substantially axial orientation is received without axial play Between two opposite walls of a recess which crosses the piston perpendicularly to its axis to allow only a tilting of the key in the recess.
- la demi-branche horizontale avant de la clé en T comporte une face tournée radialement vers la douille à partir de laquelle l'ergot fait saillie,the front horizontal half-branch of the T-shaped wrench has a face facing radially towards the bushing from which the lug protrudes,
- la clé en T est rappelée élastiquement à encontre de la paroi transversale arrière de l'évidement par deux ressorts de compression agencés entre la paroi transversale avant de l'évidement et des perçages borgnes de centrage de la clé en T qui sont agencés de part et d'autre de la douille dans la branche verticale du T,- the T-key is elastically recalled against the rear transverse wall of the recess by two compression springs arranged between the front transverse wall of the recess and blind holes for centering the T-key which are arranged on the side and other side of the socket in the vertical branch of the T,
- la douille est réalisée en un matériau comportant une limite élastique réduite et d'une grande ténacité. L'invention propose aussi un montage pour la déformation plastique d'une douille tubulaire d'un servomoteur pneumatique d'assistance au freinage du type précédemment décrit qui comporte, d'avant en arrière, un tronçon cylindrique avant tubulaire d'un diamètre extérieur déterminé, qui est fermé à son extrémité par une paroi transversale avant à partir de laquelle s'étend vers l'intérieur de la douille une collerette coaxiale annulaire déformable formant une première partie de réglage, un tronçon intermédiaire déformable du même diamètre extérieur que le tronçon avant formant une deuxième partie de réglage, et un tronçon cylindrique arrière d'un diamètre déterminé supérieur au diamètre du tronçon avant comportant au moins un face transversale arrière d'épaulement.- The sleeve is made of a material having a reduced elastic limit and a high toughness. The invention also provides an assembly for the plastic deformation of a tubular sleeve of a pneumatic brake booster of the type described above which comprises, from front to back, a cylindrical front tubular section with a determined external diameter. , which is closed at its end by a front transverse wall from which extends towards the inside of the bushing a deformable annular coaxial flange forming a first adjustment part, a deformable intermediate section of the same outside diameter as the front section forming a second adjustment part, and a rear cylindrical section of a determined diameter greater than the diameter of the front section comprising at least one rear transverse shoulder face.
Dans ce but, l'invention propose un montage du type décrit précédemment, caractérisé en ce qu'il comporte une matrice mâle et une matrice femelle tubulaires coaxiales entre lesquelles la douille est interposée pour être déformée au cours d'une opération unique de déformation par compression axiale en pressant les matrices axialement l'une contre l'autre pour obtenir simultanément des cotes déterminées des première et deuxième partie de réglage.For this purpose, the invention provides an assembly of the type described above, characterized in that it comprises a male matrix and a coaxial tubular female matrix between which the sleeve is interposed to be deformed during a single deformation operation by axial compression by pressing the dies axially against each other to obtain simultaneously determined dimensions of the first and second setting part.
Selon d'autres caractéristiques du montage :According to other characteristics of the assembly:
- le diamètre intérieur de la matrice femelle tubulaire est supérieur au diamètre extérieur du tronçon arrière de la douille, et la matrice femelle comporte une paroi transversale arrière à partir de laquelle s'étend vers l'avant une portée cylindrique sur laquelle est enfilée la douille de façon qu'une extrémité avant de la portée cylindrique prenne appui contre la collerette annulaire de la douille,- The internal diameter of the tubular female matrix is greater than the external diameter of the rear section of the sleeve, and the female matrix has a rear transverse wall from which extends a cylindrical bearing on which the sleeve is threaded forwards. so that a front end of the cylindrical seat bears against the annular collar of the sleeve,
- la matrice mâle comporte un alésage d'un diamètre correspondant au diamètre extérieur du tronçon avant de la douille dont un fond transversal avant est destiné à permettre l'appui de la paroi transversale avant d u tronçon avant de , la douille,the male matrix has a bore with a diameter corresponding to the outside diameter of the front section of the bushing, a front transverse bottom of which is intended to allow the front transverse wall of the front section of the bushing to be supported,
- la matrice mâle comporte une portée cylindrique convexe qui fait saillie vers l'arrière et qui est destinée à recevoir une première cale tubulaire de réglage de longueur déterminée agencée dans le prolongement de la matrice tubulaire femelle, - le montage comporte une entretoise tubulaire avant d'appui destinée à être enfilée sur la douille au contact axial de la face transversale d'épaulement de la douille et une deuxième cale tubulaire arrière de réglage de longueur déterminée qui sont destinées à être mises en place dans la matrice femelle entre la portée cylindrique de la matrice femelle et sa paroi cylindrique intérieure préalablement à l'opération de déformation par compression axiale,- the male matrix comprises a convex cylindrical bearing surface which projects rearwards and which is intended to receive a first tubular shim of determined length adjustment arranged in the extension of the female tubular matrix, - the assembly comprises a tubular spacer before d support intended to be threaded on the sleeve in axial contact with the transverse shoulder face of the sleeve and a second rear tubular shim of fixed length adjustment which are intended to be placed in the female matrix between the cylindrical seat of the female matrix and its internal cylindrical wall prior to the deformation operation by axial compression,
- la matrice mâle est fixe, et la matrice femelle est montée coulissante axialement pour être pressée vers la matrice mâle avec un effort de compression d'intensité déterminée.- The male matrix is fixed, and the female matrix is slidably mounted axially to be pressed towards the male matrix with a compression force of determined intensity.
D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description détaillée qui suit pour la compréhension de laquelle on se reportera aux dessins annexés dans lesquels : - la figure 1 est une vue d'ensemble d'un servomoteur réalisé conformément à l'état de la technique,Other characteristics and advantages of the invention will appear on reading the following detailed description for the understanding of which reference will be made to the appended drawings in which: FIG. 1 is an overall view of a booster produced in accordance with the state of the art,
- la figure 2 est une vue en coupe axiale de détail d'un servomoteur pneumatique d'assistance au freinage selon l'invention représenté en position inactive de l'embrayage unidirectionnel,FIG. 2 is a view in axial section of detail of a pneumatic brake booster according to the invention shown in the inactive position of the one-way clutch,
- la figure 3 est une vue en coupe axiale de détail d'un servomoteur pneumatique d'assistance au freinage selon l'invention représenté en position active de l'embrayage unidirectionnel,FIG. 3 is a view in axial section of detail of a pneumatic brake booster according to the invention shown in the active position of the one-way clutch,
- la figure 4 est une vue en coupe axiale d'une douille pour un embrayage unidirectionnel selon les figures 1 ou 2, et,FIG. 4 is a view in axial section of a socket for a one-way clutch according to FIGS. 1 or 2, and,
- la figure 5 est une vue en coupe axiale d'un montage pour la déformation plastique d'une douille selon la figure 3. Dans la description qui va suivre, des chiffres de référence identiques désignent des pièces identiques ou ayant des fonctions similaires.- Figure 5 is an axial sectional view of an assembly for the plastic deformation of a sleeve according to Figure 3. In the following description, identical reference numerals denote identical parts or having similar functions.
Par convention, les termes "avant", "arrière", supérieur", "inférieur" désignent respectivement des éléments ou des positions orientés respectivement vers la gauche, la droite, le haut, ou le bas des figures 1 à 5.By convention, the terms "front", "rear", upper "," lower "respectively designate elements or positions oriented respectively to the left, the right, the top, or the bottom of FIGS. 1 to 5.
On a représenté à la figure 1 l'ensemble d'un servomoteur 1 0 pneumatique d'assistance au freinage pour un véhicule automobile. De manière connue, le servomoteur pneumatique 10 comporte une enveloppe rigide 12 à l'intérieur de laquelle est montée une cloison 14 transversale mobile qui délimite de façon étanche une chambre avant 16, soumise à une première pression "Pi" dont la valeur est égale à la valeur de la dépression du moteur du véhicule, et une chambre arrière 18 soumise à une deuxième pression "P2". La deuxième pression "P2" est susceptible, comme il sera décrit ultérieurement, de varier entre la valeur de dépression moteur "Pi " et la valeur de la pression atmosphérique "Pa". La chambre avant 16 est alimentée en pression "P-t" par l'intermédiaire d'un conduit 20 de dépression qui est relié à une source de dépression du véhicule, par exemple une dépression régnant dans un collecteur d'admission (non représenté) d'un moteur du véhicule.FIG. 1 shows a set of a pneumatic brake booster 1 0 for a motor vehicle. In known manner, the pneumatic servomotor 10 comprises a rigid casing 12 inside which is mounted a movable transverse partition 14 which delimitably a front chamber 16, subjected to a first pressure "Pi" whose value is equal to the value of the depression of the vehicle engine, and a rear chamber 18 subjected to a second pressure "P 2 ". The second pressure "P 2 " is likely, as will be described later, to vary between the value of engine vacuum "Pi" and the value of atmospheric pressure "P a ". The front chamber 16 is supplied with pressure "Pt" via a vacuum conduit 20 which is connected to a source of vacuum in the vehicle, for example a vacuum prevailing in an intake manifold (not shown) of a vehicle engine.
Le servomoteur pneumatique 10 comporte un piston mobile 22 qui est solidaire de la cloison mobile 14. A l'intérieur de l'enveloppe 12, la cloison mobile 14 est rappelée élastiquement vers l'arrière par un ressort 24 de rappel qui prend appui sur l'enveloppe 12 et sur une face avant 26 du piston mobile 22. La face avant 26 du piston mobile 22 porte une coupelle 30 de réaction à l'intérieur de laquelle est agencé, comme on le verra plus loin , un disque de réaction 32 en matériau élastomère. Une face avant 34 de la coupelle 30 de réaction est solidaire d'une tige d'actionnement 28, qui est par conséquent solidaire des déplacements du piston mobile 22, et qui permet l'actionnement d'un maître-cylindre 36 hydraulique de freinage du véhicule.The pneumatic booster 10 comprises a movable piston 22 which is integral with the movable partition 14. Inside the casing 12, the movable partition 14 is biased elastically towards the rear by a return spring 24 which bears on the envelope 12 and on a front face 26 of the movable piston 22. The front face 26 of the movable piston 22 carries a reaction cup 30 inside which is arranged, as will be seen below, a reaction disc 32 in elastomeric material. A front face 34 of the reaction cup 30 is integral with an actuating rod 28, which is consequently integral with the displacements of the movable piston 22, and which allows the actuation of a hydraulic master cylinder 36 for braking the vehicle.
Une tige 38 de commande, qui est par exemple reliée à une pédale de frein du véhicule par l'intermédiaire d'un manchon 41 d'accouplement qui est agencé à son extrémité libre arrière 43, est susceptible de se déplacer dans le piston mobile 22, sélectivement en fonction d'un effort axial d'entrée exercé vers l'avant sur la tige 38 de commande. L'effort d'actionnement est exercé à rencontre d'un effort de rappel qui est exercé sur la tige 38 par un ressort de rappel 40 qui est interposé entre le piston mobile 22 et la tige 38 de commande.A control rod 38, which is for example connected to a brake pedal of the vehicle by means of a coupling sleeve 41 which is arranged at its rear free end 43, is capable of moving in the movable piston 22 , selectively as a function of an axial input force exerted forward on the control rod 38. The actuating force is exerted against a return force which is exerted on the rod 38 by a return spring 40 which is interposed between the movable piston 22 and the control rod 38.
Comme l'illustre plus précisément la figure 2, l'autre extrémité avant de la tige 38 de commande est conformée en rotule 42 et est reçue dans un logement complémentaire 44 d'un plongeur 46 sensiblement cylindrique q ui est monté coulissant dans le piston mobile 22.As illustrated more precisely in FIG. 2, the other front end of the control rod 38 is shaped as a ball joint 42 and is received in a complementary housing 44 of a substantially cylindrical plunger 46 which is slidably mounted in the movable piston 22.
U n siège annulaire arrière 48 du plongeur 46 fait partie d'un clapet 50 à trois voies qui est susceptible de faire varier la deuxième pression "P2" régnant dans la chambre arrière 18, notamment en mettant en communication la chambre avant 16 et la chambre arrière 18 lorsque la tige 38 de commande est en position de repos, ou en mettant progressivement la chambre arrière 18 en communication avec la pression atmosphérique "Pa" lorsque la tige 38 de commande est actionnée.A rear annular seat 48 of the plunger 46 is part of a three-way valve 50 which is capable of varying the second pressure "P 2 " prevailing in the rear chamber 18, in particular by connecting the front chamber 16 and the rear chamber 18 when the control rod 38 is in the rest position, or by gradually bringing the rear chamber 18 into communication with the atmospheric pressure "P a " when the control rod 38 is activated.
Le fonctionnement du clapet à trois voies 50 étant connu de l'état de la technique, il ne sera pas décrit plus explicitement dans la présente description.The operation of the three-way valve 50 being known from the state of the art, it will not be described more explicitly in the present description.
De manière connue, un palpeur 52 est formé à l'extrémité avant d'une douille 58 qui est montée coulissante sur l'extrémité avant du plongeur 46 qui est opposée au logement 44. L'extrémité avant de la douille 58 formant le palpeur 52 est par ailleurs montée coulissante à l'intérieur d'un alésage 54 du piston mobileIn known manner, a feeler 52 is formed at the front end of a socket 58 which is slidably mounted on the front end of the plunger 46 which is opposite to the housing 44. The front end of the socket 58 forming the feeler 52 is also slidably mounted inside a bore 54 of the movable piston
22 qui débouche en regard de la coupelle de réaction 30. De la sorte, la douille 58 et le palpeur 52 sont susceptibles d'être sollicités par le plongeur 46 pour que le palpeur 52 sollicite à son tour le disque 32 de réaction et le comprime, ce qui permet ainsi de transmettre au plongeur 46 et, ce faisant, à la tige de commande 38, l'effort de réaction du piston mobile 22 dans une position d'actionnement extrême de fin de course de la tige de commande 38.22 which opens facing the reaction cup 30. In this way, the socket 58 and the probe 52 are liable to be urged by the plunger 46 so that the probe 52 in turn urges the reaction disc 32 and compresses it , which thus makes it possible to transmit to the plunger 46 and, in doing so, to the control rod 38, the reaction force of the movable piston 22 in an extreme actuation position at the end of the travel of the control rod 38.
De manière connue, comme l'illustrent les figures 2 et 3, le servomoteur 10 comporte un dispositif 56 d'embrayage unidirectionnel qui comporte d'une part un élément de blocage faisant partie de la douille 58 coaxiale et qui comporte d'autre part un élément de verrouillage mobile qui est formé d'une clé 60 sensiblement annulaire entourant avec jeu radial la douille 58.In known manner, as illustrated in FIGS. 2 and 3, the servomotor 10 comprises a one-way clutch device 56 which comprises on the one hand a locking element forming part of the coaxial socket 58 and which on the other hand comprises a movable locking element which is formed of a substantially annular key 60 surrounding the bush 58 with radial clearance.
A cet effet, la douille coaxiale est montée coulissante sur le plongeur 46 et est rappelée élastiquement par l'interméd iaire d'un ressort 57, interposé entre le piston 22 et la douille 58, au contact avec une face transversale avant 59 du plongeur 46.To this end, the coaxial sleeve is slidably mounted on the plunger 46 and is resiliently returned by the intermediary of a spring 57, interposed between the piston 22 and the sleeve 58, in contact with a front transverse face 59 of the plunger 46 .
Par ailleurs, lorsque le servomoteur 1 0 est assemblé, la douille 58 traverse une lumière circulaire 61 de la clé 60. La clé 60 est disposée dans un évidement 62 qui traverse le piston 22 perpendiculairement à son axe "A". La clé 60 est rappelée élastiquement à encontre d'une paroi arrière 66 de l'évidement 62. De manière connue, une partie inférieure 70 de la clé 60 est, dans la position de repos représentée à la figure 2, en appui sur un support 72 qui est lié à l'enveloppe 12 du servomoteur 10. U ne goupille transversale 71 , qui traverse transversalement la douille 58 et le plongeur 46, est, en position de repos de la tige 38, en appui sur une face avant de la clé 60 pour définir la position de repos du plongeur 46.Furthermore, when the booster 1 0 is assembled, the socket 58 passes through a circular lumen 61 of the key 60. The key 60 is disposed in a recess 62 which crosses the piston 22 perpendicular to its axis "A". The key 60 is resiliently biased against a rear wall 66 of the recess 62. In known manner, a lower part 70 of the key 60 is, in the rest position shown in FIG. 2, supported on a support 72 which is linked to the casing 12 of the booster 10. A transverse pin 71, which crosses transversely the socket 58 and the plunger 46, is, in the rest position of the rod 38, bearing on a front face of the key 60 to define the rest position of the plunger 46.
De manière connue, lorsqu'un effort d'entrée est appliqué à la tige de commande 38 à une vitesse réduite, l'équilibre des pressions dans les chambres avant 16 et arrière 14 se produit suffisamment lentement pour que la cloison mobile 14, et donc le piston mobile 22, se déplacent à une vitesse sensiblement égale à celle de la douille 58 entraînée par le plongeur 46. Comme on le verra ultérieurement pour le servomoteur 1 0 objet de l'invention, le dispositif d'embrayage unidirectionnel 56 demeure alors inactif car la clé 60 est en appui sur la douille 58.In known manner, when an input force is applied to the control rod 38 at a reduced speed, the pressure balance in the front 16 and rear chambers 14 occurs slowly enough that the movable partition 14, and therefore the movable piston 22, move at a speed substantially equal to that of the socket 58 driven by the plunger 46. As will be seen later for the actuator 1 0 object of the invention, the one-way clutch device 56 then remains inactive because the key 60 is supported on the socket 58.
En revanche, comme l'illustre la figure 3, si un effort d'entrée est appliqué d'arrière en avant suivant une course extrême de la tige de commande 38 et à une vitesse déterminée de celle-ci, le plongeur 46 entraîne la douille 58 à une vitesse qui est supérieure à celle du piston mobile 22. Une partie supérieure 64 de la clé 60 est alors entraînée par le piston 22 de commande tandis que sa partie inférieure 70 quitte son appui sur le support 72. La clé 60 n'étant plus en appui sur la douille 58, elle bascule autour d'un axe g lobalement transversal et dans le sens anti- horaire pour coopérer avec un élément de blocage de la périphérie de la douille 58, notamment une face transversale arrière 76 de la douille.On the other hand, as illustrated in FIG. 3, if an input force is applied from back to front following an extreme stroke of the control rod 38 and at a determined speed thereof, the plunger 46 drives the sleeve 58 at a speed which is higher than that of the movable piston 22. An upper part 64 of the key 60 is then driven by the control piston 22 while its lower part 70 leaves its support on the support 72. The key 60 does not being more supported on the socket 58, it rocks around a generally transverse axis and counterclockwise to cooperate with a blocking element of the periphery of the socket 58, in particular a rear transverse face 76 of the socket .
De la sorte si le conducteur relâche prématurément son effort sur la tige 38, la douille 58 est bloquée par la clé 60 dans une position axiale avant extrême dans laquelle le palpeur 52 sollicite le disque de réaction 32 indépendamment du plongeur 46 et de la tige de commande 38, ce qui permet de maintenir un effort de freinage maximal tant que le retour de la tige 38 de commande n'a pas provoqué la réouverture du clapet à trois voies 50, et ainsi, le retour du piston 22 d'avant en arrière.In this way if the driver prematurely releases his force on the rod 38, the socket 58 is blocked by the key 60 in an extreme front axial position in which the probe 52 urges the reaction disc 32 independently of the plunger 46 and the control rod 38, which makes it possible to maintain a maximum braking force as long as the return of the control rod 38 does not has not caused the reopening of the three-way valve 50, and thus, the return of the piston 22 from front to back.
De manière connue, le dispositif d'embrayage unidirectionnel 56 a été représenté sur les figures comme comportant un élément de verrouillage constitué de la clé 60 précédemment décrite, mais il sera compris qu'il peut aussi comporter un élément mobile de verrouillage d'un autre type, qui soit susceptible d'immobiliser axialement de manière précise la face transversale arrière 76 de la douille 58.In known manner, the unidirectional clutch device 56 has been shown in the figures as comprising a locking element consisting of the key 60 previously described, but it will be understood that it may also include a movable locking element of another type, which is capable of immobilizing axially precisely the rear transverse face 76 of the socket 58.
Le servomoteur 10 objet de l'invention, qui va à présent être décrit plus spécifiquement en référence aux figures 2 et 3, comporte un embrayage unidirectionnel 56 dont la clé 60 comporte un ergot 78 qui est destiné, dans la position active de l'embrayage, à venir en butée contre la face transversale 76 arrière de la douille 58 formant l'élément de blocage pour effectuer un blocage de la douille 58 suivant une position axiale précise.The servomotor 10 which is the subject of the invention, which will now be described more specifically with reference to FIGS. 2 and 3, comprises a one-way clutch 56 whose key 60 includes a lug 78 which is intended, in the active position of the clutch , to come into abutment against the rear transverse face 76 of the socket 58 forming the blocking element for blocking the socket 58 according to a precise axial position.
En particulier, comme représenté à la figure 4, la douille 58 comporte un tronçon cylindrique avant 79 tubulaire dont l'extrémité forme le palpeur 52, et un tronçon cylindrique arrière tubulaire 83, d'un diamètre sensiblement supérieur au diamètre du tronçon avant, qui comporte une gorge radiale 80 dont une face transversale avant d'épaulement forme la face transversale 76 arrière de blocage. De la sorte, la gorge radiale 80 délimite dans le tronçon arrière 83 une portée cylindrique avant 81 et une portée cylindrique arrière 85.In particular, as shown in FIG. 4, the socket 58 comprises a tubular front cylindrical section 79, the end of which forms the feeler 52, and a tubular rear cylindrical section 83, with a diameter substantially greater than the diameter of the front section, which has a radial groove 80, a front transverse shoulder face forms the rear transverse face 76 for locking. In this way, the radial groove 80 delimits in the rear section 83 a front cylindrical surface 81 and a rear cylindrical surface 85.
La gorge 80 est d'un profil sensiblement tronconique en arrière de la face transversale avant 76 d'épaulement. De la sorte, l'extrémité de la gorge 80 qui est opposée à la face transversale avant 76 d'épaulement rejoint prog ressivement la périphérie cylindrique du tronçon arrière 83 de la douille 58.The groove 80 has a substantially frustoconical profile behind the front transverse face 76 of the shoulder. In this way, the end of the groove 80 which is opposite the face front transverse shoulder 76 progressively joins the cylindrical periphery of the rear section 83 of the socket 58.
Le profil tronconique de la gorge 80 de la douille 58 est particulièrement avantageux car il permet, lors du basculement de la clé 60, de guider l'ergot 78 de la clé, qui présente la forme d'un secteur angulaire tronconique concave complémentaire du profil tronconique de la gorge 80, jusqu'à sa position de butée contre la face avant d'épaulement 76 de la douille 58.The frustoconical profile of the groove 80 of the socket 58 is particularly advantageous because it allows, during the tilting of the key 60, to guide the lug 78 of the key, which has the shape of a concave frustoconical angular sector complementary to the profile frustoconical of the groove 80, to its stop position against the front shoulder face 76 of the socket 58.
La lumière circulaire 61 de la clé 60, qui entoure la douille 58, ne participe pas au blocage de la douille 58. Celui-ci est entièrement assuré par l'ergot 78.The circular opening 61 of the key 60, which surrounds the socket 58, does not participate in blocking the socket 58. The latter is entirely ensured by the lug 78.
En effet, comme l'illustrent plus particulièrement les figures 2 et 3, la clé 60 présente, en section par un plan axial, la forme générale d'un "T" dont la branche verticale 82 d'orientation sensiblement radiale comporte la lumière 61 qui est traversée par la douille 58. La clé 60 en "T" comporte une branche horizontale 84, qui est d'orientation sensiblement axiale perpendiculaire à la branche principale 82, et qui est reçue sans jeu axial entre les parois avant 68 et arrière 66 de l'évidement 62 qui traverse le piston 22 perpendiculairement par rapport à son axe "A".In fact, as illustrated more particularly in FIGS. 2 and 3, the key 60 has, in section through an axial plane, the general shape of a "T" whose vertical branch 82 of substantially radial orientation includes the lumen 61 which is crossed by the socket 58. The key 60 in "T" has a horizontal branch 84, which is of substantially axial orientation perpendicular to the main branch 82, and which is received without axial play between the front walls 68 and rear 66 of the recess 62 which crosses the piston 22 perpendicularly to its axis "A".
Cette configuration présente l'avantage de permettre seulement un mouvement de basculement de la clé 60 dans l'évidement 62. En effet, la clé 60 n'est pas susceptible de se déplacer axialement par rapport à l'évidement 62, mais peut voir sa branche 82 basculer dans l'évidement 62, conformément à la figure 3.This configuration has the advantage of allowing only a tilting movement of the key 60 in the recess 62. In fact, the key 60 is not capable of moving axially relative to the recess 62, but can see its branch 82 tilt in the recess 62, in accordance with FIG. 3.
L'ergot 78 est agencé sous la branche horizontale 84 de la clé 60 en "T". Plus particulièrement, la demi-branche 86 horizontale avant de la clé en T comporte une face tournée radialement vers la douille 58 à partir de laquelle l'ergot 78 fait saillie.The lug 78 is arranged under the horizontal branch 84 of the key 60 in "T". More particularly, the horizontal horizontal half-branch 86 of the T-shaped key has a face facing radially towards the socket 58 from which the lug 78 projects.
La clé 60 en "T" est rappelée élastiquement à rencontre de la paroi transversale 66 de l'évidement par deux ressorts de compression 94 et 95 qui sont agencés entre la paroi transversale avant 68 de l'évidement 62 et des perçages 96 borgnes de centrage de la clé 60 en T qui sont agencés de part et d'autre de la douille dans la branche verticale 82 du T.The key 60 in "T" is resiliently returned to meet the transverse wall 66 of the recess by two compression springs 94 and 95 which are arranged between the transverse wall before 68 of the recess 62 and the blind 96 holes for centering the key 60 in T which are arranged on either side of the sleeve in the vertical branch 82 of the T.
De la sorte, en l'absence d'effort sur la tige 38 de commande, la clé 60 occupe la position qui est représentée à la figure 3. Sa branche horizontale 84 est sensiblement parallèle à l'axe A du piston 22, et sa branche verticale 82 est sensiblement perpendiculaire à cet axe A.In this way, in the absence of force on the control rod 38, the key 60 occupies the position which is shown in FIG. 3. Its horizontal branch 84 is substantially parallel to the axis A of the piston 22, and its vertical branch 82 is substantially perpendicular to this axis A.
Lorsque le conducteur du véhicule actionne la tige de commande 38 suivant une vitesse relativement lente, ce qui correspond à un cas de freinage progressif, le piston mobile 22 se déplace sensiblement à la même vitesse que le plongeur 46, car l'établissement de la pression atmosphérique "Pa " s'effectue au fur et à mesure que le clapet 50 à trois voies s'ouvre. Dans cette configuration, la branche horizontale 84 étant maintenue entre les parois avant 68 et arrière 66 de l'évidement 62 sans possibilité de déplacement axial, la clé 60 bascule dès que la branche verticale 82 de la clé quitte son appui inférieur sur le support 72 solidaire de l'enveloppe 12. L'ergot 68 vient alors au contact de la douille 58 sur la portée avant 81 du tronçon arrière 83, mais ne pénètre pas instantanément dans la gorge 80 tronconique puisque la douille 58 et la piston mobile 22 se déplacent sensiblement à la même vitesse.When the driver of the vehicle actuates the control rod 38 at a relatively slow speed, which corresponds to a case of progressive braking, the mobile piston 22 moves substantially at the same speed as the plunger 46, because the establishment of the pressure atmospheric "P a " takes place as the three-way valve 50 opens. In this configuration, the horizontal branch 84 being maintained between the front 68 and rear 66 walls of the recess 62 without the possibility of axial displacement, the key 60 switches as soon as the vertical branch 82 of the key leaves its lower support on the support 72 integral with the casing 12. The lug 68 then comes into contact with the socket 58 on the front surface 81 of the rear section 83, but does not instantaneously enter the frustoconical groove 80 since the socket 58 and the movable piston 22 move at roughly the same speed.
De la sorte, si le conducteur relâche son effort, la clé 60 ne bloque pas la douille 58 et ne s'oppose pas au retour d'avant en arrière du piston mobile 22.In this way, if the driver releases his effort, the key 60 does not block the socket 58 and does not oppose the return from front to back of the movable piston 22.
En revanche, si le conducteur actionne violemment la tige 38 de commande, ce qui correspond à un cas de freinage d'urgence,, le plongeur 46 avance plus vite que ne peut le faire le piston mobile 22, du fait du retard lié à l'équilibrage de la pression dans la chambre arrière 18. De ce fait, lors du basculement de la clé 60, l'ergot 78 quitte la portée avant 81 , tombe dans la gorge 80, et glisse en butée jusqu'à la face 76 d'épaulement pour bloquer axialement de manière précise la douille 58.On the other hand, if the driver violently actuates the control rod 38, which corresponds to an emergency braking case, the plunger 46 advances faster than the movable piston 22 can do, due to the delay linked to the balancing of the pressure in the rear chamber 18. As a result, during the tilting of the key 60, the lug 78 leaves the front bearing 81, falls into the groove 80, and slides into abutment up to the face 76 shoulder to precisely lock the bush 58 axially.
Ainsi, si le conducteur relâche partiellement son effort, la clé 60 bloque la douille 58 et donc le palpeur 52, en s'opposant ainsi au retour du piston mobile 22 d'avant en arrière, indépendamment de la position du plongeur 46. Cette position permet de maintenir un effort de freinage maximal sur le piston 22.Thus, if the driver partially releases his effort, the key 60 blocks the socket 58 and therefore the probe 52, thus opposing the return of the movable piston 22 from front to back, regardless of the position of the plunger 46. This position maintains maximum braking force on piston 22.
Lorsque le conducteur relâche son effort de façon importante, le mouvement en retour de la tige 38 actionne le plongeur 46 dont la goupille 71 sollicite d'avant en arrière la branche verticale 82 de la clé 60, ce qui provoque le déverrouillage de la clé 60. De plus, le retour du plongeur 46 provoque l'ouverture du clapet à trois voies 50. Le rétablissement d'une dépression dans la chambre arrière 16 provoque le déplacement du piston 22 et, de ce fait provoque le retour de la clé 60 à sa position de repos, puisque sa branche horizontale 84 est guidée entre les parois avant 68 et arrière 66 du piston 22.When the driver releases his force significantly, the backward movement of the rod 38 actuates the plunger 46 whose pin 71 biases the vertical branch 82 of the key 60 back and forth, which causes the key 60 to be unlocked. In addition, the return of the plunger 46 causes the opening of the three-way valve 50. The re-establishment of a vacuum in the rear chamber 16 causes the piston 22 to move and, therefore, causes the key 60 to return. its rest position, since its horizontal branch 84 is guided between the front 68 and rear 66 walls of the piston 22.
Dans un tel servomoteur 10, la douille 58 comportant le palpeur 52 est montée de manière que soit établi, en position de repos, un jeu déterminé "J 1 ", représenté figure 2, entre le palpeur 52 et le disque de réaction 32.In such a booster 10, the socket 58 comprising the feeler 52 is mounted so that a determined clearance "J 1", shown in FIG. 2, is established in the rest position, between the feeler 52 and the reaction disc 32.
La valeur de ce jeu "J 1 " détermine l'effort d'assistance fourni par le piston mobile 22 pour lequel un effort de réaction est transmis, par l'intermédiaire du disque 32 de réaction, du piston mobile 22 à la tige de commande 38. La valeur de cet effort d'assistance est appelé "saut" du servomoteur 10, et il dépend des cotes du palpeur 52, notamment de l'épaisseur axiale "H 1 " du palpeur 5 représentée à la figure 4. Par ailleurs, dans un tel servomoteur 1 0, si l'effort d'entrée est exercé à une vitesse supérieure à la vitesse déterminée sur la tige 38 de commande, la position axiale de la face transversale arrière 76 formant l'élément de blocage de la douille 58 conditionne la vitesse selon laquelle le dispositif d'embrayage unidirectionnel 58 est susceptible de se déclencher. En effet, tant que l'ergot 78 de la clé 60 est susceptible d'être retenu par la portée avant 81 du tronçon arrière 83, il ne tombe pas dans la gorge 80, et le dispositif d'embrayage unidirectionnel 56 demeure inactif.The value of this clearance "J 1" determines the assistance force supplied by the mobile piston 22 for which a reaction force is transmitted, via the reaction disk 32, from the mobile piston 22 to the control rod 38. The value of this assistance effort is called "jump" of the servomotor 10, and it depends on the dimensions of the probe 52, in particular on the axial thickness "H 1" of the probe 5 shown in FIG. 4. Furthermore, in such a booster 1 0, if the input force is exerted at a speed greater than the speed determined on the control rod 38, the axial position of the rear transverse face 76 forming the locking element of the socket 58 conditions the speed at which the clutch device unidirectional 58 is likely to trip. Indeed, as long as the lug 78 of the key 60 is capable of being retained by the front bearing 81 of the rear section 83, it does not fall into the groove 80, and the one-way clutch device 56 remains inactive.
Cette vitesse est communément connue sous le nom de "vitesse de déclenchement", et est donc dépendante, comme représenté à la figure 4, de cotes de la douille, notamment de la distance axiale "H2" qui sépare une face arrière 100 du palpeur, qui est agencée au fond de l'alésage 102 de la douille 58 et sur laquelle l'extrémité transversale avant 59 du plongeur 46 est en appui pendant son mouvement d'arrière en avant, de la face transversale d'épaulement 76 la douille 58.This speed is commonly known under the name of "tripping speed", and is therefore dependent, as shown in FIG. 4, on the dimensions of the sleeve, in particular on the axial distance "H2" which separates a rear face 100 of the probe, which is arranged at the bottom of the bore 102 of the socket 58 and on which the front transverse end 59 of the plunger 46 is in support during its movement from back to front, of the transverse shoulder face 76 of the socket 58.
Conventionneliement, la douille 58 est obtenue par un procédé de tournage pour réaliser de façon précise les cotes d imensionnelles H 1 et H2 susceptibles de convenir à un bon fonctionnement du servomoteur 10.Conventionally, the socket 58 is obtained by a turning process in order to produce precisely the dimensional dimensions H 1 and H2 capable of being suitable for the correct operation of the servomotor 10.
Cette conception présente l'inconvénient de grever considérablement le prix de revient de la douille car elle nécessite de respecter des cotes précises lors de la fabrication de la douille 58 , et nécessite un contrôle unitaire de la douille 58.This design has the drawback of considerably increasing the cost price of the socket because it requires respecting precise dimensions during the manufacture of the socket 58, and requires a unitary check of the socket 58.
Pour remédier à cet inconvénient, l'invention propose une douille 58 dont les cotes peuvent être ajustées simplement par un procédé de déformation plastique. Dans ce but, la douille 58 comporte une première partie de réglage, agencée entre les faces avant et arrière du palpeur 52, et une deuxième partie de réglage, agencée entre la face arrière 100 du palpeur 52 et la face transversale arrière 76, qui sont déformables plastiquement au moins suivant la direction axiale de façon à permettre le réglage du servomoteur 10 avant son assemblage.To overcome this drawback, the invention provides a socket 58, the dimensions of which can be adjusted simply by a plastic deformation process. For this purpose, the socket 58 comprises a first adjustment part, arranged between the front and rear faces of the probe 52, and a second adjustment part, arranged between the rear face 100 of the probe 52 and the rear transverse face 76, which are plastically deformable at least in the axial direction so as to allow the actuator 10 to be adjusted before it is assembled.
A cet effet, conformément à l'invention, le tronçon avant 79 comporte une collerette annulaire intérieure 104 qui s'étend vers l'arrière, en saillie à partir de la face arrière 100 du palpeur 52, et qui est susceptible d'être déformée axialement avant le montage pour constituer la première partie de réglage permettant de régler la position , ou saut du servomoteur 10, dans laquelle le palpeur 46 sollicite le disque de réaction 32. Par ailleurs, le tronçon avant 79 et le tronçon arrière 83 de la douille 58 sont séparés par un tronçon intermédiaire 106 d'épaisseur réduite "e" qui est susceptible d'être déformé axialement pour constituer la deuxième partie de réglage permettant de régler la position de déclenchement selon laquelle l'ergot 78 de la clé 60 est reçu en butée contre la face transversale 76 arrière de blocage.To this end, in accordance with the invention, the front section 79 includes an inner annular flange 104 which extends rearwardly, projecting from the rear face 100 of the probe 52, and which is capable of being deformed axially before assembly to constitute the first adjustment part making it possible to adjust the position, or jump of the servomotor 10, in which the probe 46 urges the reaction disc 32. Furthermore, the front section 79 and the rear section 83 of the socket 58 are separated by an intermediate section 106 of reduced thickness "e" which is capable of being deformed axially to constitute the second adjustment part making it possible to adjust the release position according to which the lug 78 of the key 60 is received in abutment against the rear transverse blocking face 76.
A cet effet, la douille 58 est notamment réalisée en un matériau comportant une limite élastique réduite et d'une grande ténacité, et elle est déformée dans un montage 108 de déformation , représenté à la figure 5, qui est spécialement destiné à la déformation de la douille 58.To this end, the sleeve 58 is in particular made of a material comprising a reduced elastic limit and of great toughness, and it is deformed in a deformation assembly 108, represented in FIG. 5, which is specially intended for the deformation of the socket 58.
Le montage 108 comporte une matrice mâle 1 10 et une matrice femelle tubulaires 1 12 coaxiales entre lesquelles la douille 58 est interposée pour être déformée au cours d'une opération unique de déformation par compression axiale en pressant les matrices 1 10 et 1 12 axialement l'une contre l'autre pour obtenir simultanément les cotes déterminées "H 1 " et H2" des première et deuxième parties de réglage.The assembly 108 comprises a male matrix 1 10 and a female tubular matrix 1 12 coaxial between which the sleeve 58 is interposed to be deformed during a single deformation operation by axial compression by pressing the dies 1 10 and 1 12 axially l 'one against the other to simultaneously obtain the determined dimensions "H 1" and H2 "of the first and second adjustment parts.
En particulier le diamètre intérieur Dh i2 de la matrice femelle 1 12 tubulaire est supérieur au diamètre extérieur De83 du tronçon arrière 83 de la douille 58, de façon à permettre la réception de la douille 58 dans la matrice femelle 1 12. La matrice femelle 1 12 comporte une paroi transversale arrière 1 14 à partir de laquelle s'étend vers l'avant une portée cylindrique 1 16 sur laquelle est enfilée la douille 58 de façon qu'une extrémité avant 1 18 de la portée cylindrique 1 16 prenne appui contre la collerette annulaire 104 de la douille 58.In particular, the internal diameter D h i 2 of the tubular female matrix 1 12 is greater than the external diameter D e83 of the rear section 83 of the socket 58, so as to allow reception of the socket 58 in the female matrix 1 12. female matrix 1 12 has a rear transverse wall 1 14 from which extends a cylindrical seat 1 16 forwardly on which the sleeve 58 is threaded so that a front end 1 18 of the cylindrical seat 1 16 takes pressing against the annular flange 104 of the socket 58.
La matrice mâle 1 10 comporte un alésage 120 d'un diamètre correspondant au diamètre extérieur De79 du tronçon avant 79 de la douille 58. Un fond transversal avant 122 de l'alésage 120 est destiné à permettre l'appui de la paroi transversale avant 59 du tronçon avant 79 de la douille 58.The male die 1 10 has a bore 120 with a diameter corresponding to the outside diameter D e 79 of the section front 79 of the socket 58. A front transverse bottom 122 of the bore 120 is intended to allow the support of the front transverse wall 59 of the front section 79 of the socket 58.
La matrice mâle 1 10 comporte une portée cylindrique convexe 124 qui fait saillie vers l'arrière et qui est destinée à recevoir une première cale tubulaire 126 de réglage de longueurThe male die 1 10 has a convex cylindrical surface 124 which projects rearward and which is intended to receive a first tubular shim 126 for adjusting the length
"L126" déterminée qui est agencée dans le prolongement de la matrice tubulaire 1 12 femelle."L 126 " determined which is arranged in the extension of the tubular matrix 1 12 female.
Le montage 108 comporte une entretoise tubulaire 128 avant d'appui qui destinée à être enfilée sur la douille 58 au contact axial de la face transversale d'épaulement 76 de la douille 58 une deuxième cale tubulaire arrière 130 de rég lage de longueur "Lι 30" déterminée qui sont destinées à être mises en place dans la matrice femelle 1 12 entre la portée cylindrique 1 16 de la matrice femelle et sa paroi cylindrique intérieure 1 32 préalablement à l'opération de déformation par compression axiale.The assembly 108 comprises a tubular spacer 128 before support which is intended to be threaded on the sleeve 58 in axial contact with the transverse shoulder face 76 of the sleeve 58 a second rear tubular wedge 130 for adjusting the length "Lι 30 "determined which are intended to be placed in the female matrix 1 12 between the cylindrical surface 1 16 of the female matrix and its inner cylindrical wall 1 32 prior to the deformation operation by axial compression.
Ainsi, Les cales tubulaires 126 et 130 peuvent être remplacées, d'un type de servomoteur à l'autre, pour obtenir des valeurs différentes des cotes "H 1 " et "H2".Thus, the tubular shims 126 and 130 can be replaced, from one type of servomotor to another, to obtain values different from the dimensions "H 1" and "H2".
Dans cette configuration, l'obtention de la cote "H 1 " est déterminée par la relation :In this configuration, obtaining the dimension "H 1" is determined by the relationship:
H 1 - L110/1 + L-|26 - Li 12/1 (R1 )H 1 - L110 / 1 + L- | 26 - Li 12/1 (R1)
dans laquelle Ln0/ι désigne la cote de la matrice 1 10 qui sépare son fond transversal avant 122 d'un épaulement 132 sur lequel la première cale tubulaire 126 vient en appui, et dans laquelle Ln2/1 désigne la cote de la matrice 1 12 qui sépare son extrémité avant 1 34 sur lequel la première cale tubulaire 126 vient en appui de l'extrémité avant 1 18 de la portée cylindrique 1 16.in which Ln 0 / ι denotes the dimension of the matrix 1 10 which separates its front transverse bottom 122 from a shoulder 132 on which the first tubular wedge 126 comes to bear, and in which Ln 2/1 denotes the dimension of the matrix 1 12 which separates its front end 1 34 on which the first tubular shim 126 comes to bear on the front end 1 18 of the cylindrical seat 1 16.
D'une façon analogue, l'obtention de la cote "H2" est déterminée par la relation : H2 = Li 12/2 _ L-130 - Ll 28 (R2)In an analogous way, obtaining the "H2" rating is determined by the relationship: H2 = Li 12/2 _ L-130 - Ll 28 (R2)
dans laquelle Ln2/2 désigne la cote de la matrice 1 12 qui sépare l'extrémité avant 1 18 de sa portée cylindrique 1 16 de la paroi transversale arrière 1 14, et dans laquelle L-ι28 désigne la longueur de l'entretoise.in which Ln 2/2 denotes the dimension of the matrix 1 12 which separates the front end 1 18 from its cylindrical seat 1 16 from the rear transverse wall 1 14, and in which L-ι 2 8 denotes the length of the spacer.
Ainsi, comme on peut le voir à la figure 5, les cotes H 1 etThus, as can be seen in FIG. 5, the dimensions H 1 and
H2 dépendent directement des longueurs des cales tubulaires 126 et 130. Typiquement, lors de l'opération de déformation, chacune des cotes H 1 ou H2 initiales est réduite de 0 à 0.5 mm.H2 directly depend on the lengths of tubular shims 126 and 130. Typically, during the deformation operation, each of the initial dimensions H 1 or H2 is reduced from 0 to 0.5 mm.
Enfin lors de la déformation de la douille 58, la matrice mâle 1 10 est fixe, et la matrice femelle 1 12 est montée coulissante axialement pour être pressée vers la matrice mâle avec un effort F d'intensité déterminée. L'orientation de l'effort de compression F et son point d'application sont représentés à la figure 5.Finally during the deformation of the socket 58, the male die 1 10 is fixed, and the female die 1 12 is slidably mounted axially to be pressed towards the male die with a force F of determined intensity. The orientation of the compressive force F and its point of application are shown in FIG. 5.
L'invention permet donc avantageusement de bénéficier d'un servomoteur 10 d'un coût réduit permettant de bénéficier effort de freinage maximal dans des situations de freinage d'urgence, quel que soit le comportement du conducteur après un freinage violent. The invention therefore advantageously makes it possible to benefit from a booster 10 of a reduced cost making it possible to benefit from maximum braking force in emergency braking situations, whatever the behavior of the driver after violent braking.

Claims

REVEN DICATIONS 1. Servomoteur (10) pneumatique d'assistance au freinage pour un véhicule automobile, du type qui comporte une enveloppe (12) rigide à l'intérieur de laquelle est mobile une cloison (14) transversale délimitant de façon étanche une chambre avant (16), soumise à une première pression (P-i) de dépression moteur, et une chambre arrière (18) soumise à une deuxième pression (P2) variant entre la dépression moteur et la pression atmosphérique (Pa), du type qui comporte un piston mobile (22) solidaire de la cloison mobile (14) se déplaçant avec la cloison mobile (14) et une tige (38) de commande se déplaçant dans le piston (22) sélectivement en fonction d'un effort axial d'entrée exercé vers l'avant à encontre d'un effort de rappel exercé sur la tige (38) par un ressort de rappel (40), du type dans lequel la tige (38) est mobile suivant une position d'actionnement intermédiaire ou une position d'actionnement extrême obtenue lorsque l'effort d'entrée est appliqué à une vitesse élevée déterminée, du type qui comporte un plongeur (46) qui est agencé à l'avant de la tige (38) de commande dans le piston (22) et un clapet à trois voies (50) qui comporte au moins un siège annulaire (48) arrière du plongeur (46) et qui est susceptible de faire varier la deuxième pression (P2) régnant dans la chambre arrière (18), notamment en mettant en communication la chambre avant (16) et la chambre arrière (18) lorsque la tige (38) de commande est en position de repos ou en mettant progressivement la chambre arrière ( 18) en communication avec la pression atmosphérique (Pa) lorsque la tige (38) de commande est actionnée, du type dans lequel, dans la position extrême d'actionnement de la tige (38) de commande, une face arrière d'un palpeur (52) monté coulissant à l'extrémité avant du plongeur (46) est sollicitée par le plongeur (46) de manière qu'une face avant du palpeur (52) vienne au contact d'un disque (32) de réaction solidaire du piston (22) mobile pour transmettre au plongeur (46) et à la tige (38) de commande l'effort de réaction du piston mobile (22), et du type qui comporte un dispositif (56) d'embrayage unidirectionnel qui comporte au moins une douille (58) coaxiale tubulaire qui coulisse sur le plongeur (46) et dont l'extrémité avant comporte le palpeur (52), et un élément de verrouillage (60) qui est mobile entre une position active dans laquelle il ne coopère pas avec la douille (58) et une positon active, commandée par la position extrême d'actionnement de la tige (38) de commande, dans laquelle il coopère avec un élément de blocage (76) de la douille (58) pour la bloquer dans une position axiale avant extrême de manière que le palpeur (52) bloque le piston mobile (22) indépendamment du plongeur (46) et de la tige de commande (38), caractérisé en ce que la douille (58) comporte une première partie de réglage (104), agencée entre les faces avant et arrière du palpeur (52), et une deuxième partie de réglage (106), agencée entre la face arrière du palpeur (52) et l'élément de blocage (76) , qui sont déformables plastiquement au moins suivant la direction axiale de façon à permettre le réglage du servomoteur (10) avant son assemblage.REVEN DICATIONS 1. Pneumatic brake booster (10) for a motor vehicle, of the type which comprises a rigid casing (12) inside which is movable a transverse partition (14) delimitably sealing a front chamber (16), subjected to a first pressure (Pi) of engine depression, and a rear chamber (18) subjected to a second pressure (P 2 ) varying between engine depression and atmospheric pressure (P a ), of the type which comprises a movable piston (22) integral with the movable partition (14) moving with the movable partition (14) and a control rod (38) moving in the piston (22) selectively as a function of an axial input force exerted forward against a return force exerted on the rod (38) by a return spring (40), of the type in which the rod (38) is movable in an intermediate actuation position or a position extreme actuation obtained when the input effort e is applied at a determined high speed, of the type which comprises a plunger (46) which is arranged at the front of the control rod (38) in the piston (22) and a three-way valve (50) which comprises at least one annular seat (48) rear of the plunger (46) and which is capable of varying the second pressure (P 2 ) prevailing in the rear chamber (18), in particular by bringing the front chamber (16) and the rear chamber (18) when the control rod (38) is in the rest position or by gradually bringing the rear chamber (18) into communication with atmospheric pressure (P a ) when the control rod (38) is actuated, type in which, in the extreme actuation position of the control rod (38), a rear face of a feeler (52) slidably mounted at the front end of the plunger (46) is biased by the plunger (46) so that a front face of the probe (52) comes into contact with a reaction disc (32) ion secured to the movable piston (22) for transmitting to the plunger (46) and to the control rod (38) the reaction force of the movable piston (22), and of the type which includes a one-way clutch device (56) which comprises at least one coaxial tubular sleeve (58) which slides on the plunger (46) and the front end of which comprises the feeler (52), and a locking element (60) which is movable between an active position in which it does not cooperate with the socket (58) and an active position, controlled by the extreme actuation position of the control rod (38), in which it cooperates with a blocking element (76 ) of the sleeve (58) for locking it in an extreme front axial position so that the feeler (52) blocks the movable piston (22) independently of the plunger (46) and the control rod (38), characterized in that that the sleeve (58) has a first adjustment part (104), arranged between the front and rear faces of the probe (52), and a second adjustment part (106), arranged between the rear face of the probe (52) and the locking element (76), which are plastically deformable at least ins in the axial direction so as to allow the actuator (10) to be adjusted before it is assembled.
2. Servomoteur (10) selon la revendication précédente, caractérisé en ce que l'élément de verrouillage est formé d'une clé (60) sensiblement annulaire qui entoure avec jeu la douille (58) et qui est susceptible, lorsque l'effort d'entrée est appliqué à la vitesse déterminée, d'être entraînée par le piston (22) mobile pour basculer autour d'un axe g lobalement transversal de manière qu'un ergot (78) de la clé (60) vienne en butée contre une face transversale (76) arrière de la douille (58) formant l'élément de blocage.2. Booster (10) according to the preceding claim, characterized in that the locking element is formed by a key (60) substantially annular which surrounds with play the sleeve (58) and which is susceptible, when the force d input is applied at the determined speed, to be driven by the movable piston (22) to tilt around a generally transverse axis so that a lug (78) of the key (60) comes into abutment against a transverse face (76) rear of the sleeve (58) forming the locking element.
3. Servomoteur (10) selon la revendication précédente, caractérisé en ce que la douille (58) comporte un tronçon cylindrique avant (79) tubulaire, dont l'extrémité forme le palpeur (52) et un tronçon cylindrique arrière (83) tubulaire, d'un diamètre (Des3) sensiblement supérieur au diamètre (Dθ79) du tronçon avant (79) qui comporte une gorge radiale (80) dont une face transversale avant d'épaulement (76) forme la face transversale arrière de blocage.3. Booster (10) according to the preceding claim, characterized in that the sleeve (58) comprises a tubular front cylindrical section (79), the end of which forms the feeler (52) and a tubular rear cylindrical section (83), with a diameter (D e s3) substantially greater than the diameter (D θ 79) of the front section (79) which has a radial groove (80), one face front transverse shoulder (76) forms the rear transverse locking face.
4. Servomoteur (10) selon la revendication précédente, caractérisé en ce que le tronçon avant (79) comporte une collerette annulaire intérieure (1 04) qui s'étend vers l'arrière, en saillie à partir de la face arrière (100) du palpeur (52), et qui est susceptible d'être déformée axialement avant le montage pour constituer la première partie de réglage permettant de régler la position, ou saut du servomoteur (10), dans laquelle le palpeur (52) sollicite le disque de réaction (32).4. Booster (10) according to the preceding claim, characterized in that the front section (79) has an inner annular flange (1 04) which extends rearwardly, projecting from the rear face (100) of the probe (52), and which is capable of being deformed axially before mounting to constitute the first adjustment part making it possible to adjust the position, or jump of the servomotor (10), in which the probe (52) urges the disc of reaction (32).
5. Servomoteur (10) selon l'une des revendications 3 ou 4, caractérisé en ce que le tronçon avant (79) et le tronçon arrière (83) de la douille sont séparés par un tronçon intermédiaire (106) d'épaisseur (e) réduite qui est susceptible d'être déformé axialement pour constituer la deuxième partie de réglage permettant de régler la position de déclenchement selon laquelle l'ergot (78) de la clé (60) est reçu en butée contre la face transversale (76) arrière de blocage.5. Booster (10) according to one of claims 3 or 4, characterized in that the front section (79) and the rear section (83) of the sleeve are separated by an intermediate section (106) of thickness (e ) reduced which is capable of being deformed axially to constitute the second adjustment part making it possible to adjust the release position according to which the lug (78) of the key (60) is received in abutment against the rear transverse face (76) blocking.
6. Servomoteur (10) selon l'une des revendications 3 à 5, caractérisé en ce que la gorge (80) est d'un profil sensiblement tronconique en arrière de la face transversale (76) avant d'épaulement.6. Booster (10) according to one of claims 3 to 5, characterized in that the groove (80) is of a substantially frustoconical profile behind the transverse face (76) before shoulder.
7. Servomoteur (10) selon la revendication précédente, caractérisé en ce que l'ergot (78) présente la forme d'un secteur angulaire tronconique concave qui est complémentaire du profil tronconique de la gorge (80) de la douille (58).7. Booster (10) according to the preceding claim, characterized in that the lug (78) has the shape of a concave frustoconical angular sector which is complementary to the frustoconical profile of the groove (80) of the sleeve (58).
8. Servomoteur (10) selon l'une des revendications 2 à 7, caractérisé en ce que la clé (60) présente, en section par un plan axial, la forme d'un "T" dont la branche verticale (82) d'orientation sensiblement radiale est traversée par la douille (60) et dont la branche horizontale (84), d'orientation sensiblement axiale est reçue sans jeu axial entre deux parois opposées (66, 68) d'un évidement (62) qui traverse le piston (22) perpendiculairement par rapport à son axe (A) pour ne permettre qu'un basculement de la clé (60) dans l'évidement (62).8. Booster (10) according to one of claims 2 to 7, characterized in that the key (60) has, in section through an axial plane, the shape of a "T" whose vertical branch (82) d the substantially radial orientation is traversed by the sleeve (60) and the horizontal branch (84) of substantially axial orientation of which is received without axial play between two opposite walls (66, 68) of a recess (62) which passes through the piston (22) perpendicularly by relative to its axis (A) to allow only a tilting of the key (60) in the recess (62).
9. Servomoteur (10) selon la revendication précédente, caractérisé en ce que la demi-branche horizontale avant (86) de la clé (60) en T comporte une face tournée radialement vers la douille (58) à partir de laquelle l'ergot (78) fait saillie.9. Booster (10) according to the preceding claim, characterized in that the front horizontal half-branch (86) of the key (60) in T has a face facing radially towards the sleeve (58) from which the lug (78) protrudes.
1 0. Servomoteur (10) selon la revendication précédente, caractérisé en que la clé (60) en T est rappelée élastiquement à encontre de la paroi transversale arrière (66) de l'évidement (62) par deux ressorts de compression (94, 95) agencés entre la paroi transversale avant (68) de l'évidement (62) et des perçages (96) borgnes de centrage de la clé (60) en T qui sont agencés de part et d'autre de la douille (58) dans la branche verticale (82) du T.1 0. Booster (10) according to the preceding claim, characterized in that the key (60) in T is resiliently biased against the rear transverse wall (66) of the recess (62) by two compression springs (94, 95) arranged between the front transverse wall (68) of the recess (62) and blind holes (96) for centering the key (60) in T which are arranged on either side of the socket (58) in the vertical branch (82) of the T.
1 1 . Servomoteur (10) selon l'une quelconque des revendications précédentes, caractérisé en ce que la douille (58) est réalisée en un matériau comportant une limite élastique réduite et d'une grande ténacité.1 1. Booster (10) according to any one of the preceding claims, characterized in that the sleeve (58) is made of a material comprising a reduced elastic limit and of great toughness.
12. Montage (108) pour la déformation plastique d'une douille (58) tubulaire d'un servomoteur (10) pneumatique d'assistance au freinage selon la revendication 1 , qui comporte, d'avant en arrière, un tronçon cylindrique avant (79) tubulaire d'un diamètre extérieur (De7g) déterminé, qui est fermé à son extrémité par une paroi transversale avant (100) à partir de laquelle s'étend vers l'intérieur de la douille une collerette coaxiale annulaire ( 104) déformable formant une première partie de réglage, un tronçon intermédiaire (106) déformable du même diamètre extérieur que le tronçon avant (79) formant une deuxième partie de réglage, et un tronçon cylindrique arrière (83) d'un diamètre déterminé (Des3) supérieur au diamètre (De79) du tronçon avant (79) comportant au moins un face transversale arrière d'épaulement (76), caractérisé en ce qu'il comporte une matrice mâle (1 10) et une matrice femelle (1 12) tubulaires coaxiales entre lesquelles la douille (58) est interposée pour être déformée au cours d'une opération unique de déformation par compression axiale en pressant les matrices (1 10, 1 12) axialement l'une contre l'autre pour obtenir simultanément des cotes (H1 , H2) déterminées des première (104) et (106) deuxième partie de réglage. 12. Assembly (108) for the plastic deformation of a tubular bush (58) of a pneumatic brake booster (10) according to claim 1, which comprises, from front to back, a front cylindrical section ( 79) tubular with a determined external diameter (D e7 g), which is closed at its end by a front transverse wall (100) from which extends towards the inside of the sleeve an annular coaxial flange (104) deformable forming a first adjustment part, a deformable intermediate section (106) of the same outside diameter as the front section (79) forming a second adjustment part, and a rear cylindrical section (83) of a determined diameter (D e s3 ) greater than the diameter (D e79 ) of the front section (79) comprising at least one rear transverse shoulder face (76), characterized in that it comprises a male matrix (1 10) and a female matrix (1 12) coaxial tubulars between which the sleeve (58) is interposed to be deformed during a unique operation of deformation by axial compression by pressing the dies (1 10, 1 12) axially against each other to simultaneously obtain dimensions (H1, H2) determined from the first (104) and (106) second adjustment part .
13. Montage (108) selon la revendication précédente, caractérisé en ce que le diamètre intérieur (D 2) de la matrice (1 12) femelle tubulaire est supérieur au diamètre extérieur (Dβ83) du tronçon arrière de la douille (58), et en ce que la matrice femelle (1 12) comporte une paroi transversale arrière (1 14) à partir de laquelle s'étend vers l'avant une portée cylindrique (1 16) sur laquelle est enfilée la douille (58) de façon qu'une extrémité avant (1 18) de la portée cylindrique prenne appui contre la collerette annulaire (104) de la douille (58).13. Assembly (108) according to the preceding claim, characterized in that the internal diameter (D 2 ) of the matrix (1 12) tubular female is greater than the external diameter (D β83 ) of the rear section of the sleeve (58), and in that the female matrix (1 12) has a rear transverse wall (1 14) from which extends forward a cylindrical seat (1 16) on which is threaded the sleeve (58) so that 'a front end (1 18) of the cylindrical seat bears against the annular flange (104) of the sleeve (58).
14. Montage (108) selon l'une des revendications 12 ou 13, caractérisé en ce que la matrice mâle (1 10) comporte un alésage (120) d'un diamètre correspondant au diamètre extérieur (DΘ79) du tronçon avant (79) de la douille (58) dont un fond transversal avant (122) est destiné à permettre l'appui de la paroi transversale avant du tronçon avant (79) de la douille (58). 14. Assembly (108) according to one of claims 12 or 13, characterized in that the male die (1 10) has a bore (120) with a diameter corresponding to the outside diameter (D Θ79 ) of the front section (79 ) of the sleeve (58) including a front transverse bottom (122) is intended to allow the support of the front transverse wall of the front section (79) of the sleeve (58).
15. Montage (108) selon l'une des revendications 13 ou 14, caractérisé en ce que la matrice mâle (1 10) comporte une portée (124) cylindrique convexe qui fait saillie vers l'arrière et qui est destinée à recevoir une première cale (126) tubulaire de réglage de longueur (Lι2β) déterminée agencée dans le prolongement de la matrice (1 12) tubulaire femelle.15. Assembly (108) according to one of claims 13 or 14, characterized in that the male matrix (1 10) has a convex cylindrical surface (124) which projects rearward and which is intended to receive a first shim (126) tubular length adjustment (Lι 2 β) determined arranged in the extension of the matrix (1 12) tubular female.
16. Montage (108) selon l'une des revendications 13 à 15, caractérisé en ce qu'il comporte une entretoise tubulaire avant (128) d'appui destinée à être enfilée sur la douille (58) au contact axial de la face transversale d'épaulement (76) de la douille (58) et une deuxième cale (130) tubulaire arrière de réglage de longueur (Lι 30) déterminée qui sont destinées à être mises en place dans la matrice femelle (1 12) entre la portée cylindrique (1 16) de la matrice femelle et sa paroi cylindrique intérieure ( 132) préalablement à l'opération de déformation par compression axiale.16. Assembly (108) according to one of claims 13 to 15, characterized in that it comprises a front tubular spacer (128) for support intended to be threaded on the sleeve (58) in axial contact with the transverse face shoulder (76) of the sleeve (58) and a second rear tubular shim (130) of length adjustment (Lι 30 ) determined which are intended to be placed in the female matrix (1 12) between the cylindrical seat (1 16) of the female matrix and its inner cylindrical wall (132) prior to the axial compression deformation operation.
17. Montage selon l'une des revendications 12 à 16, caractérisé en ce que la matrice mâle (1 10) est fixe, et en ce que la matrice femelle (1 12) est montée coulissante axialement pour être pressée vers la matrice mâle (1 10) avec un effort (F) de compression d'intensité déterminée. 17. Assembly according to one of claims 12 to 16, characterized in that the male matrix (1 10) is fixed, and in that the female matrix (1 12) is slidably mounted axially to be pressed towards the male matrix ( 1 10) with a compression force (F) of determined intensity.
PCT/EP2001/006459 2000-05-22 2001-05-18 Brake servo unit comprising a bushing adjustable by deformation, and assembly for adjusting the bushing WO2001089901A1 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
PL01359000A PL359000A1 (en) 2000-05-22 2001-05-18 Brake servo unit comprising a bushing adjustable by deformation, and assembly for adjusting the bushing
MXPA02012187A MXPA02012187A (en) 2000-05-22 2001-05-18 Brake servo unit comprising a bushing adjustable by deformation, and assembly for adjusting the bushing.
JP2001586107A JP2003534198A (en) 2000-05-22 2001-05-18 Servomotor with deformable sleeve and equipment for adjusting this sleeve
EP01955302A EP1289817A1 (en) 2000-05-22 2001-05-18 Brake servo unit comprising a bushing adjustable by deformation, and assembly for adjusting the bushing
AU77504/01A AU774150B2 (en) 2000-05-22 2001-05-18 Brake servo unit comprising a bushing adjustable by deformation, and assembly for adjusting the bushing
BR0111337-2A BR0111337A (en) 2000-05-22 2001-05-18 Servomotor with an adjustable deformation joint and configuration for adjusting the deformation joint of a servomotor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR00/06601 2000-05-22
FR0006601A FR2809067B1 (en) 2000-05-22 2000-05-22 SERVOMOTOR WITH A BUSH ADJUSTABLE BY DEFORMATION, AND MOUNTING TO ADJUST THE BUSH

Publications (1)

Publication Number Publication Date
WO2001089901A1 true WO2001089901A1 (en) 2001-11-29

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PCT/EP2001/006459 WO2001089901A1 (en) 2000-05-22 2001-05-18 Brake servo unit comprising a bushing adjustable by deformation, and assembly for adjusting the bushing

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EP (1) EP1289817A1 (en)
JP (1) JP2003534198A (en)
KR (1) KR20030010630A (en)
CN (1) CN1438952A (en)
AU (1) AU774150B2 (en)
BR (1) BR0111337A (en)
FR (1) FR2809067B1 (en)
MX (1) MXPA02012187A (en)
PL (1) PL359000A1 (en)
RU (1) RU2002134472A (en)
WO (1) WO2001089901A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002094628A1 (en) * 2001-05-25 2002-11-28 Bosch Sistemas De Frenado, S.L. Servo brake booster with two differentiated fixed and variable jumps
WO2002094627A1 (en) * 2001-05-25 2002-11-28 Bosch Sistemas De Frenado, S.L. Servo brake booster with differentiated jumps
FR2825057A1 (en) * 2001-05-25 2002-11-29 Bosch Sist De Frenado Sl Pneumatic brake servomotor comprises low pressure and variable pressure chambers and three-way valve activated by brake pedal rod, during braking variable pressure chamber communicates with high pressure
FR2922174A1 (en) * 2007-10-12 2009-04-17 Bosch Gmbh Robert Pneumatic servomotor for assisting braking in motor vehicle, has blocking key axially located against transmission piece such that groove arrives at key and key is inserted in groove for permitting sensors to act on piece

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2825056B1 (en) * 2001-05-25 2003-09-19 Bosch Sist De Frenado Sl AIR VARIABLE JUMP HEIGHT BRAKE ASSIST MOTOR
FR2844495B1 (en) * 2002-09-12 2005-06-10 Bosch Sist De Frenado Sl BRAKE ASSIST SERVOMOTOR COMPRISING AN EMERGENCY BRAKE DEVICE, METHOD OF ADJUSTING A THRESHOLD OF ACTIVATION THRESHOLD OF THE DEVICE, AND DEVICE FOR CARRYING OUT SAID METHOD
FR2855135B1 (en) * 2003-05-22 2005-07-15 Bosch Gmbh Robert PNEUMATIC BRAKE ASSIST SERVOMOTOR

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2074270A (en) * 1980-04-16 1981-10-28 Lucas Industries Ltd Servo valves for brake boosters
DE3205268A1 (en) * 1982-02-15 1983-08-25 Alfred Teves Gmbh, 6000 Frankfurt Brake servo unit with adjustable fastening of a spring plate

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2074270A (en) * 1980-04-16 1981-10-28 Lucas Industries Ltd Servo valves for brake boosters
DE3205268A1 (en) * 1982-02-15 1983-08-25 Alfred Teves Gmbh, 6000 Frankfurt Brake servo unit with adjustable fastening of a spring plate

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002094628A1 (en) * 2001-05-25 2002-11-28 Bosch Sistemas De Frenado, S.L. Servo brake booster with two differentiated fixed and variable jumps
WO2002094627A1 (en) * 2001-05-25 2002-11-28 Bosch Sistemas De Frenado, S.L. Servo brake booster with differentiated jumps
FR2825058A1 (en) * 2001-05-25 2002-11-29 Bosch Sist De Frenado Sl FIXED AND VARIABLE TWO-DIFFERENTIAL JUMP SERVO MOTOR
FR2825057A1 (en) * 2001-05-25 2002-11-29 Bosch Sist De Frenado Sl Pneumatic brake servomotor comprises low pressure and variable pressure chambers and three-way valve activated by brake pedal rod, during braking variable pressure chamber communicates with high pressure
FR2825059A1 (en) * 2001-05-25 2002-11-29 Bosch Sist De Frenado Sl DIFFERENTIATED JUMP SERVOMOTOR
WO2002102634A2 (en) * 2001-05-25 2002-12-27 Bosch Sistemas De Frenado, S.L. Pneumatic brake booster with variable jump height
WO2002102634A3 (en) * 2001-05-25 2003-10-16 Bosch Sist De Frenado Sl Pneumatic brake booster with variable jump height
US6935705B2 (en) * 2001-05-25 2005-08-30 Robert Bosch Gmbh Servo brake booster with two differentiated fixed and variable jumps
FR2922174A1 (en) * 2007-10-12 2009-04-17 Bosch Gmbh Robert Pneumatic servomotor for assisting braking in motor vehicle, has blocking key axially located against transmission piece such that groove arrives at key and key is inserted in groove for permitting sensors to act on piece

Also Published As

Publication number Publication date
KR20030010630A (en) 2003-02-05
EP1289817A1 (en) 2003-03-12
FR2809067A1 (en) 2001-11-23
MXPA02012187A (en) 2004-08-19
FR2809067B1 (en) 2002-08-09
CN1438952A (en) 2003-08-27
RU2002134472A (en) 2004-05-27
AU774150B2 (en) 2004-06-17
BR0111337A (en) 2003-06-17
PL359000A1 (en) 2004-08-23
AU7750401A (en) 2001-12-03
JP2003534198A (en) 2003-11-18

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