Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D25/00—Fluid-actuated clutches
  • F16D25/08—Fluid-actuated clutches with fluid-actuated member not rotating with a clutching member
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
  • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
  • B60T11/16—Master control, e.g. master cylinders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
  • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
  • B60T11/16—Master control, e.g. master cylinders
  • B60T11/22—Master control, e.g. master cylinders characterised by being integral with reservoir
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D25/00—Fluid-actuated clutches
  • F16D25/08—Fluid-actuated clutches with fluid-actuated member not rotating with a clutching member
  • F16D25/088—Fluid-actuated clutches with fluid-actuated member not rotating with a clutching member the line of action of the fluid-actuated members being distinctly separate from the axis of rotation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D25/00—Fluid-actuated clutches
  • F16D25/12—Details not specific to one of the before-mentioned types
  • F16D25/126—Details not specific to one of the before-mentioned types adjustment for wear or play

Definitions

• the invention relates to a hydraulic circuit, in particular a clutch. More particularly, it relates to a transmitting device, capable of transmitting hydraulically a control order to a receiving device.
• the master cylinder comprises two main parts which are, on the one hand, a cylinder-piston assembly, the piston of which is actuated by a pedal, for example a clutch, and, on the other hand, a fluid reservoir hydraulic, intended to compensate for variations in the volume of the fluid due to wear of the clutch linings or to possible leaks in the hydraulic circuit.
• a pedal for example a clutch
• a fluid reservoir hydraulic intended to compensate for variations in the volume of the fluid due to wear of the clutch linings or to possible leaks in the hydraulic circuit.
• Devices of this kind are for example described in the document FR-A-2 522 757. They generally comprise, between the reservoir and the hydraulic chamber defined by the cylinder and in which the piston moves, a non-return means allowing the circuit to be refilled in the rest position and the circuit to be pressurized.
• the seals ensuring the tightness of the pressure chamber often consist of a seal carried by the piston or, as in the above document, of a flexible membrane disposed between the piston and the cylinder; the central part of this membrane, fixed by its periphery to the cylinder, follows the longitudinal movements of the piston during clutch and disengage actions.
• These joints are subjected on one of their faces to a fluid environment, and on the other to an atmospheric environment which results in a dry and often polluted surface. This difference in environment and the action of the pressure lead these seals to a relatively limited life, which is the source of potentially dangerous leaks, here for the user of the vehicle. 2
• the receiving devices placed at the end of the hydraulic circuit, for example in line with the clutch bearing, are in principle of operation and of design substantially identical to those of the transmitters. They naturally present the same problems of implementation in traditional technology.
• the invention relates to a transmitting device for a hydraulic circuit making it possible to ensure optimal conditions for the reliable operation of the seal and also to prevent its premature wear and aging, and therefore to ensure a lasting seal, where increased operational safety for this critical member, especially when fitted to a rolling vehicle.
• the transmitter device is simple and economical to manufacture.
• the invention provides a transmitter for hydraulic control, intended to be controlled by a control member and comprising a hydraulic chamber, in which a piston is mounted slidingly sealed, thanks to a seal which it carries, and defines therein.
• a pressure chamber of variable volume connected to a hydraulic pipe, a hydraulic fluid tank connected to said pressure chamber by at least one passage, means preventing the return of fluid to the tank (6) during the pressurization of the pipe , a means of transmitting the movement of the control member to the piston, characterized in that the hydraulic chamber is extended along its longitudinal axis by a reserve volume, adapted to receive the piston in its rest position, when the circuit n is not pressurized, said reserve volume containing hydraulic fluid to a level sufficient for the seal to be embedded therein, the hydraulic chamber and the e reserve volume being provided in a single housing, and in that the transmission means consists of at least two parts, one of which is internal to the housing and connected to the piston, the other of which 3 is external to the housing, the two parts being connected by means passing through the
• the piston and therefore the seal which it carries is completely and durably submerged in the hydraulic fluid.
• the reserve volume is adapted to contain hydraulic fluid up to a normal level of fluid to constitute the re-supply reservoir of the hydraulic pipe.
• the part internal to the housing crosses the free surface of the liquid and the means passing through the housing crosses the latter above the level of the liquid.
• the seals ensuring the tightness of the pressure chamber during the pressurization of the circuit are immersed in the hydraulic fluid, on one side within the pressure chamber, the other within the tank, which ensures perfect lubrication and eliminates pollution and the action of air, therefore wear and aging of the seal. It is also understood that one can be satisfied here with a seal closing the pressure chamber of the simple type, any marginal fluid leaks out of the pressure chamber being here "recycled", the fluid then simply returning to the tank. of fluid. This obviously contributes to savings on the choice of seals of the emitting device, while increasing overall reliability.
• this arrangement also prevents the entry of air bubbles and polluting particles in the hydraulic circuit in the opposite direction, insofar as the cylinder is completely immersed in the fluid.
• the means for transmitting the movements of the piston comprises three levers secured to a free shaft rotating around a horizontal axis and passing through the side walls of the housing above the normal level of fluid in the reserve volume, one of the said internal levers being included in the tank and the two other so-called external levers being outside the housing, on either side of the latter.
• Such a symmetrical arrangement leads to a symmetry of the forces avoiding parasitic reactions on the axis A of articulation of the levers;
• the hydraulic chamber and the reserve volume are integrated into the housing, which is substantially symmetrical along a vertical plane comprising the longitudinal axis of the pressure chamber, the side walls of the housing being mainly vertical, and the three levers being of geometry identical; - the three levers have identical lengths to further reduce parasitic reactions on the A axis;
• connection of the levers on the shaft advantageously comprises bushes fitted on the shaft between these levers;
• the sockets are ratchet sockets made of a harder material than that of the levers and on which the levers are embedded;
• the housing has on the outer faces of its side walls ribs forming stops to limit the maximum amplitude of the movements of the levers. 5
• These different arrangements are adapted to allow a simple implementation of a two-part transmission means whose connection between the two parts is arranged outside the hydraulic fluid, here above the normal level of the fluid in the reservoir.
• the rotary seals ensuring the seal between the internal part of the control device and the external part work at a low amplitude, which is favorable to simplicity of manufacture, at low cost and to an extended service life.
• the piston preferably has a head in the form of a spherical crown taking into account the maximum tilting angle of the piston, due to the trajectory of its rear part by which it is connected to the internal lever;
• the passages connecting the reservoir to the pressure chamber are ridges cut into the interior wall of the cylindrical chamber at its outlet in the reserve volume, these ridges being in the direction substantially parallel to the longitudinal axis of the cylindrical chamber ;
• the passages connecting the reservoir to the pressure chamber are ridges formed on the external periphery of a ring fitted in a recess formed inside the housing at the entrance to the cylindrical chamber with which they communicate by axial play ;
• At least the ends of the grooves are arranged at an angle relative to the longitudinal axis of the cylindrical chamber in a manner corresponding to the rest position of the piston;
• the means preventing the return of fluid to the tank during the pressurization of the circuit is constituted by the seal;
• the seal is a simple technology seal, for example O-ring or rectangular section, placed in line with the ends of the grooves when the piston is in the rest position.
• the invention also relates to a hydraulic control comprising a transmitter as above, advantageously associated with a hydraulic receiver of structure similar to that of the transmitter.
• the hydraulic control comprises a receiver comprising a hydraulic chamber, a piston mounted to slide in the hydraulic chamber in order to define there a pressure chamber of variable volume connected to the hydraulic pipe, a means of transmitting the movements of the piston to the outside, means for sealing the pressure chamber, said receiver being characterized in that the pressure chamber is extended along its longitudinal axis by a downstream volume adapted to receive the piston in its pressure position, when the circuit is pressurized, the chamber cylindrical and the downstream volume being integrated in a single housing, and the transmission means consists of at least two parts, one of which is internal to the housing and the other of which is external to the housing, the two parts being connected by means passing through the wall of the housing in a sealed manner.
• the transmission means comprises three levers secured to a free shaft rotating around a horizontal axis passing through the side walls of the housing, one of the so-called internal levers being located in the housing and the other two so-called external levers , external to the case, being symmetrical and of length greater than that of the internal lever.
• the control is a hydraulic clutch control
• the clutch comprises elastic tightening means and declutching means constituted by declutching levers and, a declutching stop intended to act on the end of the declutching levers for the 7 declutching the clutch being provided
• the helical spring subjects the internal lever to a force such that, by means of the external levers, the clutch release bearing is in contact with the clutch release levers, the elastic means of tightening the clutch having a load much higher than that of the helical spring.
• FIG. 2 is a longitudinal sectional view of the transmitter, according to ll-ll of Figure 5;
• - Figure 3 is a diagram showing the path of the piston in the housing;
• FIG. 4 is a partial sectional view showing the replenishment streaks of the hydraulic fluid circuit
• FIG. 5 is a sectional view along V-V of Figure 2;
• - Figure 6 is a view similar to Figure 4 and shows an alternative embodiment;
• FIG. 7 is a partial sectional view along VII-VII of Figure 6, without the piston;
• FIG. 8 is a sectional view of the receiver according to VIII-VIII of Figure 9;
• FIG. 9 is a partially sectional view of the receiver, in front view.
• a hydraulic device comprises a transmitter 1 and a receiver 2, between which is installed a pipe 3 of hydraulic fluid transmitting the volume variations created in 8 the transmitter 1, under the effect of a control means 4, to the receiver 2.
• the receiver 2 is intended to actuate consequently any mechanical device, for example here a clutch 5.
• the emitter 1 mainly consists of a piston 8, sliding in a cylindrical hydraulic chamber 9, and therefore defining therein a variable volume intended to contain a hydraulic fluid.
• the piston 8 is naturally removed from the bottom of the chamber 9 by a spring 1 0, which defines a rest position. It is moved in the opposite direction by the action of a control rod 1 1 connected to the control means 4, here a clutch pedal.
• the volume variations thus generated are transmitted to the receiver 2, of a structure similar to that of the transmitter 1, with a piston whose movements are linked to the movements of the control piston 8, provided that no pressure drop occurs in the circuit.
• the piston of the receiver 2 actuates here the declutching stop 1 1 1 associated with the clutch 5.
• the entire transmitter 1 is included in a housing 14 which includes both the cylindrical chamber 9, which represents the maximum volume of the pressure chamber 44 that limits the piston 8, and a reserve volume 45 of the piston-8, placed in the rear extension of the cylindrical chamber 9.
• the piston 8 is therefore placed in this reserve volume 45 in the rest position.
• the housing 14 is not completely full of fluid: on the contrary it includes an air zone 51 at ambient pressure, above the normal level of fluid 1 5; a volume of reserve fluid is defined between the upper level of the cylindrical chamber 9 and the normal level of fluid 1 5 in the housing 1 4.
• the piston 8 is articulated on one end of a lever 1 6 internal to the housing 1 4, the other end of this lever 1 6 being movable in rotation around 9 of an axis A disposed above the normal level 1 5 of fluid in the housing 1 4.
• this articulation around the axis A defines for the end of the internal lever 1 6 articulated on the piston 8 a rotational movement of an amplitude of about 60 °, which is translated at the piston 8 by a longitudinal movement in the cylindrical chamber 9 combined with a lateral displacement on either side of the longitudinal axis B of the cylindrical chamber 9.
• the rest position which is the most right on FIG. 3
• the articulation of the piston 8 is arranged slightly above the axis B, at point C in FIG. 3; at mid-stroke, this articulation is slightly below this axis, at point D and, in the fully depressed position, this articulation is again above the longitudinal axis B, at point E.
• the corresponding positions of the front part of the piston 8 are identified by the points C, D ', E' in FIG. 3.
• the piston 8 is therefore not permanently in a position coaxial with the longitudinal axis B, but on the contrary moves away from it. a maximum angle 48 of a few degrees.
• the trajectory of the head 1 7 of the piston 8 is guided by the inner wall of the cylindrical chamber 9. To do this, the head 1 7 of the piston 8 is swiveled according to a spherical crown of amplitude being worth at least twice the maximum angle 48, to allow the frictionless advance of the piston 8 in the cylindrical chamber 9.
• the external diameter 49 of the body of the piston 8, in its central part, is less than the internal diameter 50 of the cylindrical chamber 9, to take account of the lateral displacements of the piston 8 in particular in the full-stroke and half-stroke positions, positions EE 'and D-D', respectively.
• FIGS. 2 and 4 The device ensuring the sealing of the pressure chamber 44 in line with the piston 8 is visible in FIGS. 2 and 4, the piston 8 being in its most advanced position E, FIG. 2, and in its rest position C, FIG. 4, respectively.
• This seal is ensured by a seal 1 8, here O-shaped, in a rectangular section variant, disposed at the front of the piston 8 and maintained in 10 places by lugs 57 for tightening a metal jacket 1 9 conforming to the internal shape of the piston 8, here hollow.
• a conventional type seal is used, and, according to the invention, its two faces are immersed in the hydraulic fluid, which provides an increased life to the seal.
• the latter On the side of the fluid line 3, the latter comprises at its end a connection 20 made of rigid material, which has on its periphery anti-recoil beads 21 adapted to be forced into the cylindrical bore 58 formed in the nose 22 of the housing 1 4.
• the seal is completed on this side by another O-ring type 23 held in place by a support washer 24.
• the helical spring 1 0 return intended to push the piston 8 towards its rest position C, bears on the housing side on this washer 24 and on the piston side on the bottom of the jacket 1 9: thus, the return spring 1 0 simultaneously performs a function of holding in place and pressurizing the two seals sealing 1 8 and 23.
• grooves 25 To allow the hydraulic fluid circuit to be filled from the volume of reserve fluid or reservoir, grooves 25, better visible in FIG.
• the ridges 25 are offset laterally, that is to say arranged at an angle relative to the longitudinal axis B, to take account of the angle 48 of lateral offset of the piston 8 in this rest position C.
• the lowest streaks 25 are therefore the most offset towards the interior of the tank. So as soon as the piston 1 1 8 is actuated, the advance of the seal 1 8 of the piston 8 beyond the ridges 25 ensures sealing simultaneously over its entire circumference, and the hydraulic circuit is then pressurized, which improves the response time to stresses.
• the ridges 25 are formed at the outer periphery of a ring 46 fitted in a recess 47 formed inside the housing 1 4 at the entrance of the cylindrical chamber 9; they communicate with said chamber 9 by an axial clearance 55 provided between the solid part of the ring 46 and the bottom of the recess 47; this play is free, as can be seen in FIG. 6, when the piston 8 is at rest; the gasket 1 8 of the piston 8 cooperates, in this position, with the internal continuous cylindrical wall of the ring 46.
• the transmission of the movement commands of the piston 8 is achieved by the joining, at the level of the axis of rotation A of the internal lever 1 6, of two levers 26, 27 external to the housing 1 4 and of this internal lever 1 6.
• the action on the external levers 26, 27 then naturally results in a movement of rotation of the internal lever 1 6, and therefore in a displacement of the piston 8.
• FIG. 5 The detail of the mechanical mounting of this connection is visible in FIG. 5. It is produced for example by the use of ratchet bushings 29, 30 arranged on a shaft 28 on either side of the internal lever 1 6. These bushings 29, 30 are made of a material harder than that of the levers to be joined.
• the housing 14 has in its side walls 52, 53 two circular bores 31, 32, respectively, of a size adapted to allow the passage of the ratchet bushings 29, 30.
• the external levers 26, 27 are fitted on the shaft 28 and tightened in place by crimping 33 of the ends of the shaft 28, or by equivalent means, in an angular position identical to that of the internal lever 1 6. Of course, after tightening, the crimping could be replaced by welding.
• ratchets on the sockets 29.30 causes, when the levers are tightened, an incrustation of the ratchets in the 12 softer material of the levers, which ensures the angular positioning of the levers and their joining in rotation.
• the external levers 26, 27 have the same geometry as that of the internal lever 1 6; the control rod 1 1 has a U-shaped end, each wing of which is articulated on one of the two external levers 26, 27: this makes it possible to avoid a lateral imbalance of the forces.
• the movement of the external levers 26, 27 is identical, by construction, as seen above, to that of the internal lever 1 6. Front ribs 36 and rear 37 are produced on the external lateral walls 52, 53 of the housing 14 to constitute limit stops for travel of the external levers 26, 27, and thus limit the movement of the internal lever 1 6 in the housing 1 4, therefore of the piston 8, and avoid possible internal damage to the piston 8 or to the housing 1 4 during excessive movements of the control pedal 4.
• the housing 1 4 is in fact composed of two elements: on the one hand, the body of the housing, which forms the major part which includes the nose, the cylindrical chamber and the reservoir, and, on the other hand, a rear cover 38, which closes the housing.
• the housing is preferably made of relatively hard plastic and the internal ridges 25 and external ribs 36, 37 are made by molding.
• the cover 38 is made of a less hard plastic material; it is forcibly fitted onto the body of the housing, by a flange 39 which it presents and which engages with a peripheral notch 40 13 formed at the periphery of the housing body, a long joint 54 of circular section being inserted into the assembly and tightened during the latter.
• the cover 38 has two bores or orifices located above the normal level of fluid 1 5, in which are housed two valves 41, 42, intended for the equalization of the air pressures between the interior and the exterior of the housing , one 42 of the valves serving for the admission of air into the tank, and the other 41 for the air exhaust from this tank.
• the valve 42 also allows the filling of the reservoir with hydraulic fluid.
• These valves 41, 42 are of a conventional nature, identical and mounted in opposite directions to one another, to perform the two functions of exhaust and suction. However, they provide sealing against hydraulic fluid, under normal atmospheric pressure.
• the hydraulic receiver 2 can be of any type. However, in the preferred embodiment of a hydraulic control, in particular a clutch control, it is designed according to a principle analogous to that of the transmitter 1.
• the receiver 2 has a very compact shape and is well suited for application to a clutch control.
• the receiver 2 comprises a housing 1 1 4, which comprises both a cylindrical chamber 109 and a downstream volume 145, for a piston 1 08, placed in the extension of the cylindrical chamber 109.
• the section of the cylindrical chamber 109, in which the piston 108 of the receiver 2 moves is significantly larger than that of the transmitter 1, the force applied to the piston 108 of the receiver 2 being then increased. , with respect to the control force applied to the piston 8 of the transmitter 1, in a ratio equal to the ratio of the surfaces of the pistons 8 and 108.
• the piston 108 is articulated on one end of a lever 1 1 6 internal to the housing 1 1 4, the other end of this internal lever 1 1 6 being movable in 14 rotation about an axis A 'extending above the longitudinal axis B' of the cylindrical chamber 109, the axes A 'and B' being orthogonal.
• the piston 108 has a hollow hemispherical sculpture in its front face 68, in which is inserted the end or head 69 of the internal lever 1 1 6, of complementary shape.
• the horizontal axis A ′ of rotation of the internal lever 1 1 6 is disposed substantially above the neck 147 of the cylindrical chamber 109, which also contributes to reducing the length of the receiver 2.
• the internal lever 1 1 6 has a curved profile allowing it to bypass the neck 1 47 of the cylindrical chamber 109.
• the internal lever 1 1 6 has a section from top to bottom , along its longitudinal axis, such that the reduction in local width linked to the curved shape of the profile is compensated by a thickness 70 greater at this location.
• the articulation of the piston 108 on the internal lever 1 1 6 defines for the head 69 of the internal lever 1 1 6 a rotational movement of an amplitude of approximately 10 °, which results in the sculpture of the front face 68 of the piston 1 1 6 by a longitudinal movement in the cylindrical chamber 109 combined with a lateral displacement around the longitudinal axis B 'of the cylindrical chamber 109.
• the head of the piston 108 is here again guided in the cylindrical chamber 109.
• the piston 108 has a substantially frustoconical periphery, the angle of which takes account of the maximum angle of inclination of the piston linked to its movement around the head of the internal lever 1 1 6 during its longitudinal displacement.
• the device ensuring the sealing of the pressure chamber 1 44 is visible in FIG. 6, in which the piston 108 is shown in its most depressed position in the cylindrical chamber 109.
• a seal 1 1 8 here an O-ring
• an O-ring placed in front of the piston 1 08 and held in place by clamping lugs of an applicator 1 1 9 conforming to the internal shape of the piston 108, here 15 also hollow and, on the other hand, by an O-ring 62 here, in a rectangular section variant, inserted between the bottom of the cylindrical chamber 109 and a metal jacket 60 conforming to the shape of the cylindrical chamber 109 which it lines internally ; more precisely, this metal jacket 60 is bored in line with the outlet 63 of a hydraulic channel 61 which the O-ring 62 surrounds.
• a helical spring 110 bears, on the housing side, on the jacket 60, and, on the piston side 108, on the applicator 119; it thus ensures a function of holding in place and tightening the seals 118 and 62.
• the transmission of the movement commands of the piston 108 is carried out by the joining, at the level of the axis of rotation A ′ of the internal lever 116, of two levers 126, 127 external to the housing 114 and of this internal lever 116. It is then understood that the displacement of the piston 108, under the effect of a command transmitted in the hydraulic channel 61 connected to a supply duct 73 itself connected to the pipe 3, causes a movement of rotation of the internal lever 116 around the 'axis A', and therefore a rotation of the external levers 126, 127.
• the external levers 126, 127 are symmetrical to each other. They are of a length greater than that of the internal lever 116. They constitute a fork for transmitting the forces to the declutching stop 111.
• the angular movement of the external levers 126, 127 is identical, by construction, to that of the internal lever 116 .
• FIG. 7 The detail of the mechanical assembly of the three levers 116, 126 and 127 is visible in FIG. 7. It is produced in a generally identical manner to the assembly of the three levers 16, 26 and 27 of the transmitter 1.
• ratchet bushings 129, 130 arranged on a shaft 128 on either side of the central internal lever 116.
• the housing 114 has in its side walls 152, 153 two circular bores 131, 132, details adapted to allow the passage of the shaft 128 surrounded by ratchet bushings 129, 130, themselves 16 surrounded by bearings 66, 67.
• the external levers 1 26, 1 27 are fitted onto the shaft 1 28 and clamped in place against the ratchet bushings 1 29, 1 30 and the internal lever 1 1 6, by crimping.
• Two lip seals 64, 65 are mounted on the outer surface of the ratchet bushings 1 29, 1 30, between the internal lever 1 1 6 and the bearings 66, 67.
• the lip seals 64, 65 work very little in the measurement where the angular displacement of the shaft 1 28 is limited to approximately plus or minus 10 °.
• the housing 1 1 4 is preferably made of injected aluminum according to a known technique. It comprises two external fixing lugs 1 43 of the conventional type.
• a rear cover 1 38 closes the housing 1 1 4.
• This cover 1 38 is made of a flexible material, such as an elastomer, in the form of a membrane adapted to deform elastically to absorb the variation in volume due to the advance of the piston when the circuit is pressurized. It is fitted onto the body of the housing 1 14, a collar 1 39 for example metal coming from engaging the edge of the cover 1 38 with a peripheral notch 1 40 formed on the body of the housing 1 14.
• the downstream volume 1 45 is normally filled with hydraulic fluid; to prevent the diaphragm 1 38 from being subjected to a resident internal pressure, the casing 1 1 4 has in its upper part a nozzle 71 connected to a tube 72 for returning the fluid to the reservoir of the transmitter, below the level normal 1 5 thereof, and preferably in the lower part of the reserve volume 45, which keeps the receiver 2 filled with fluid; thus, the membrane 1 38 is temporarily deformed, the time it takes for the fluid to pass through the nozzle 71.
• the operation of the transmitter 1 and the receiver 2 according to the invention is conventional and generally conforms to the operation of a traditional hydraulic control circuit. It has been partially described above.
• the transmitter 1 according to the invention is installed in a similar manner to that of a conventional master cylinder, or even in replacement of these on a 17 existing vehicle, the fixing flanges 43 which it comprises being designed to be compatible with conventional spacings in this area.
• the control rod 1 1 is attached to the external levers 26, 27, and the pipe 3 is connected to the housing 1 4.
• the receiver 2 according to the invention is also installed in the traditional way.
• the emitter 1 according to the invention is used conventionally.
• the piston 8 At rest, here in engaged mode, the piston 8 is in the rear position C under the effect of the spring 10. The ridges 25 then allow the passage of the fluid.
• the piston 8 is acted upon and advances in the chamber 9, passing on, beyond the passage of the ridges 25, or the axial clearance 55, on the receiver 2 a variation volume that causes the clutch.
• the grooves are arranged so that the passage of the grooves to the bore does not cause any injury to the seal.
• Many variants can be considered depending on the circumstances of use, both with regard to the method of securing the internal and external levers (welding the levers on the sockets can provide an effective solution), as the detail of the piston or streaks of re-supply of hydraulic fluid.
• the scope of the present invention is not limited to the details of the above embodiments considered by way of example, but on the contrary extends to modifications within the scope of a person skilled in the art.

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• 1999
  • 1999-04-09 WO PCT/FR1999/000840 patent/WO1999053210A1/fr not_active Application Discontinuation
  • 1999-04-09 US US09/423,527 patent/US6298968B1/en not_active Expired - Fee Related
  • 1999-04-09 KR KR1019997011535A patent/KR20010013528A/ko not_active Application Discontinuation
  • 1999-04-09 DE DE19980708T patent/DE19980708T1/de not_active Withdrawn
  • 1999-04-09 JP JP55127599A patent/JP2002505732A/ja active Pending
  • 1999-04-09 EP EP99915795A patent/EP0988463A1/de not_active Withdrawn

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