FR2811046A1 - Hydraulic actuator for motor vehicle clutch has clutch coaxial to crankshaft with actuator seating in recess in end of crankshaft - Google Patents

Abstract

The hydraulic actuator is for a motor vehicle clutch mounted between the vehicle gearbox and the free end of the crankshaft (11). The clutch is coaxial to the crankshaft extension and the hydraulic actuator is partially seated in a recess (13) formed in the crankshaft end. The actuator has an annular piston which is fixed for rotation but slidable.

Description

The subject of the present invention is a hydraulic stop serving for the

  control of a clutch fitted to a motor vehicle.

  More specifically, it is intended for a motor vehicle which is driven by an engine such as a heat engine via a gearbox, this clutch being interposed between a free end portion, designated "nose" , the engine crankshaft and an end portion of the gearbox input shaft. The invention also relates to a clutch provided with such a

hydraulic stop.

  In known manner, the free end portion of the input shaft of the gearbox is guided in rotation by means of a bearing

  suitable bearing, in a bore in the "nose" of the crankshaft.

  This ensures perfect relative centering of the two shafts, which are capable of rotating relative to each other when the clutch is not

coupled.

  When the clutch is coupled, the two shafts rotate together. Traditionally, the clutch comprises a disc immobilized in rotation, but capable of sliding in translation, over a stroke

  limited, on the input shaft of the gearbox.

  To this end, this shaft carries a grooved portion on which engage complementary grooves provided in the central opening of the disc. In the outer portion of the disc, on each of its faces is

  provided an annular seal having a high coefficient of friction.

  The "nose" of the crankshaft is integral with a flywheel which has the general shape of a discoid plate, the face of which faces the gearbox has a flat annular face, and located opposite and near the trim

of the aforementioned disc.

  On the other side of the disc (towards the gearbox), is arranged an annular plate, or "pressure plate", carried by a cover in general shape

  plate which is fixed by its periphery to the flywheel.

  This plate therefore rotates at the same time as the flywheel but

  has a certain freedom of movement in axial translation.

  It is stressed by an elastic disc with radial slots, or

  diaphragm, which also rotates at the same time as the steering wheel.

  The diaphragm can selectively assume, from a substantially planar configuration, in a plane perpendicular to the axis of the input shaft of the gearbox, a slightly conical configuration, in one direction

or in the other.

  The diaphragm is deformed by an actuating member

  with hydraulic control usually designated "hydraulic stop".

  This stop traditionally includes a piston which can slide

in a folder (cylinder).

  The piston bears against the central zone of the diaphragm by

  via a ball bearing plate.

  Means are provided for bringing hydraulic fluid under

  pressure inside the hydraulic stop.

  Generally, in the absence of hydraulic pressure, the deformation of the diaphragm is such that the clutch is coupled, this coupling being effected by friction, because the peripheral annular lining of the clutch disc is sandwiched between, on the one hand , the aforementioned wall of the flywheel and, on the other hand, the

  pressure plate mentioned above.

  The clutch is uncoupled by supplying hydraulic fluid inside the stop, which has the effect of reversing the direction of taper of the diaphragm, by eliminating the clamping force which previously existed between the

  disc and the surrounding surfaces.

  Known devices of the above-mentioned type are relatively bulky in the axial direction, because the axial dimensions of the stop,

  its bearing support plate, diaphragm, and flywheel are added.

  However, in certain circumstances, it is advantageous to obtain a

  as compact as possible.

  This is the case for example, in the case of a hybrid propulsion vehicle, which is powered by a heat engine and / or an electric motor, the

  vehicle being equipped with these two types of engine.

  In fact, in this case, there is added to this space that of the electric motor which, too, is generally disposed in the same end portion.

  the input shaft of the gearbox.

  The objective of the invention is, with a clutch of the type recalled below

  above, very significantly increase the compactness in the axial direction.

  This objective is achieved, in accordance with the present invention, thanks to the fact that the hydraulic stop is partly housed inside a recess which is formed in the "nose" of the crankshaft. In a preferred embodiment, this hydraulic stop comprises an annular piston guided in translation and immobilized in rotation on said end portion of the input shaft of the gearbox, as well as a sleeve in the form of a cylindrical sleeve. , integral with said shaft and guided in rotation inside said recess, the annular piston being adapted to slide axially inside the jacket, in one direction or the other, as a result of

  the supply or the escape of a hydraulic fluid between these two elements.

  Advantageously, the hydraulic stop comprises an elastic means, such as a spring, which constantly biases said piston, tending to

  move in the clutch coupling direction.

  The clutch, which is also part of the present invention and which is provided with a hydraulic stop as mentioned above, is remarkable in that it comprises, on the one hand, a flywheel comprising a discoid flange fixed on the crankshaft "nose", which extends in a transverse plane, perpendicular to the axis common to the crankshaft and to the input shaft of the gearbox, a cylindrical outer portion centered on this axis , and a flat annular part fixed to this cylindrical outer portion, in parallel and opposite the external zone of said flange and, on the other hand, a clutch disc guided in translation and immobilized in rotation on said end portion of the input shaft of the gearbox, this disc being interposed between said discoid flange and said flat annular piece, against which it can be applied and in

  be secured under the effect of an axial pressure.

  In a preferred embodiment, the application of the disc against said flat annular part, under the effect of an axial pressure, is carried out by means of a diaphragm which is integral in rotation with the flywheel, and whose deformation is

  governed by the translational movement of said annular piston.

  The stop is advantageously supplied with hydraulic fluid by

  one or more channels drilled in the input shaft of the gearbox.

  Other characteristics and advantages of the invention will become apparent from the

  description and attached drawing, which represents, by way of nonlimiting example, a

possible embodiment.

  In this drawing, Figure 1 (single figure) shows the clutch in

axial section.

  We can see on the right of the figure the end portion 10 of

  the crankshaft 1 of an internal combustion engine not shown.

  It is for example a four-stroke engine, petrol or diesel type. The end part of the primary shaft of a manual or automatic gearbox of known type has been designated by the reference 2, which is also not shown. It is housed in a housing C, the outline of which is represented by a dashed dashed line, and the wall of which has a guide bearing of

tree 2.

  As is well known, the end 10 of the crankshaft 1 has a portion 11 of larger diameter, which will be designated hereinafter "nose"

of crankshaft.

  This "nose" 11 has a base 12, to which a flywheel is attached

of inertia 3.

  This has the general shape of a drum comprising a cylindrical outer portion 31 and a discoid flange 30 provided with a central opening

  by which it is fitted to the "nose" 11, by applying against the base 12.

  The fixing is ensured for example by means of peripheral screws,

  of which only the axes, referenced 100, have been shown in the figure.

  According to an essential characteristic of the invention, the "nose" 11 is pierced with an axial recess 13, of generally cylindrical shape, which opens out into

  direction of tree 2 (to the left of the figure).

  In this recess partially penetrates a cylindrical sleeve 6 - or ring -, coaxial with the crankshaft 1, and guided in rotation by means of a bearing

  bearing 62 mounted in the recess 13.

  The sleeve 6 has the general shape of a cup with a stamped cylindrical wall, provided with a bottom which is fixed to the end of the shaft 2, by means

a screw 61.

  The shaft 2 has a grooved portion 20, on which can

  slide, in a well known manner, the hub 50 of a clutch disc 5.

  This hub 50 has peripheral grooves complementary to the grooves of the portion 20, which ensures its connection in rotation with

  the shaft 2, while allowing its free axial translation, over a limited stroke.

  The clutch disc 5 has, in its border area, a lining 52 with a high coefficient of friction, which protrudes slightly on each

of its two faces.

  Between this zone carrying the annular lining 52 and the hub 50 is arranged a damper 51 of known type, which ensures a certain freedom of movement in torsion, in the circumferential direction, between the outside and the inside of the disc 5, so to avoid jolts in the transmission of

  movement between these two parts at the time of mating.

  The drum-shaped flywheel 3 is open in the direction of the gearbox, that is to the left of the figure, the cylindrical wall 31 extending

a little beyond disc 5.

  At this level is mounted a flat annular part 4, which extends in a transverse plane, perpendicular to the axis XX 'common to the crankshaft 1 and to

tree 2.

  It is an annular plate having a large circular central opening 40 which is fixed by its outer border zone 41 against the face

  transverse of the wall 31 of the steering wheel.

  The fixing can be carried out by means of screws, of which only the lines

  axis have been represented and designated by the reference 300.

  The annular part 4 is located opposite the lining 52, on the side

  of the gearbox (on the left, if we consider figure 1).

  On the other side (on the right of the figure), also facing the lining 52, is an annular pressure plate 80 which, in known manner,

  cooperates, via a profiled surface, with a diaphragm 8.

  It is held inside the steering wheel 3 by a cage 9, integral with this steering wheel; the diaphragm 8 is a split elastic disc, held in its median zone against a pinched part of the part 9, part which constitutes a zone of tilting of the diaphragm, with respect to its flat shape shown, towards a

  slightly conical shape, on one side or the other.

  The annular pressure plate 80 is integral in rotation with the diaphragm 8, and therefore with the flywheel 3, by virtue of a fixing system of known type, but is movable in the axial direction at the same time as the edge zone.

  outside of the diaphragm. This type of assembly is well known.

  The device comprises a piston 7 which has an inner part

  70, the outer wall of which is cylindrical, mounted inside the ring 6.

  Part 70 has a grooved internal opening, adapting to

  complementary grooves 21 provided at the free end of the shaft 2.

  The part 7 is therefore integral in rotation with the shaft 2, but is movable

  in translation on the latter along the axis XX ′, over a certain stroke.

  The part 70 can therefore slide inside the cylindrical part of the ring 6, and this in a sealed manner, the external diameter of the part 70

  corresponding to the internal diameter of the ring 6.

  The assembly constitutes a single-acting hydraulic cylinder, the

  jacket (cylinder body) is constituted by the ring 6, and the piston by the part 70.

  Appropriate seals may be provided to perfect

this tightness.

  On the outside of the ring 6, the part 70 is extended by a flat annular part 71, extending perpendicular to the axis XX ′, and the portion of which

  outer is adapted to receive a thrust ball bearing 72.

  One of the abutment cages is integral with the piston 7, while

  the other part is integral with the inner edge of the diaphragm 8.

  We understand that thanks to this arrangement, there is a possibility of relative rotation of the piston 7 relative to the diaphragm 8, and that the axial movement of this piston causes a deformation of the diaphragm and, correspondingly, a

  displacement of the annular pressure plate 80, in one direction or the other.

  More specifically, a movement to the right of the piston 7 causes the movement of the plate 80 to the left; conversely moving towards the

  the left of the piston 7 causes a displacement to the right of the plate 80.

  The piston 7 has a central bore 720, of diameter substantially larger than that of the shaft portion 2, in a zone extending

from Part 71 to Part 70.

  In this bore is mounted an elastic member constituted by a helical compression spring 23 which surrounds the shaft 2 and bears, on one side, against the piston part 70, and on the other on a stop element 22 , such as

retaining ring, integral with the shaft 2.

  The assembly 7-6 constitutes the hydraulic stop of the clutch.

  The hydraulic chamber of this stop, referenced 600, corresponds to the free space, of variable volume, delimited by the bottom of the ring 6 and the face

  front end (right side) of the piston part 70.

  The hydraulic fluid is supplied to this chamber 600 by means of a central bore 200 drilled in the shaft 2, as well as in the screw 61, this

  bore opening on radial channels 201 communicating with said chamber.

  At the opposite end of the shaft 2 is installed a hydraulic distribution system, not shown, with a rotating joint, capable of allowing the supply and the escape of the hydraulic liquid in these channels 200 - 201,

for clutch control.

  In Figure 1 the clutch is shown in a situation

  intermediate coupling (flat diaphragm).

  In the absence of hydraulic pressure in the chamber 600, the spring 23 tends to move the piston 7 to the right of the figure, in the direction of the clutch; in fact, as indicated above, this direction of displacement of the piston gives the diaphragm a conical configuration such that it pushes the pressure plate to the left, trapping the lining 52 between this plate 80 and the part 4. The flywheel 3 is located thus secured by friction with the clutch disc 5, so that the crankshaft 1 drives in its rotation

tree 2.

  If the chamber 600 is supplied with pressurized hydraulic fluid, as symbolized by the arrow F, the piston 7 is moved towards the

  left, compressing spring 23.

  Correlatively, the diaphragm 8 is deformed in the opposite direction,

  moving the pressure plate 80 away from the disc 5.

  The latter is therefore free to rotate relative to the flywheel 3, and

  the two shafts 1 and 2 are mutually uncoupled.

  Thanks to the architecture of this stop, as can be easily understood from a simple observation of the figure, a remarkable compactness is obtained, the hydraulic stop being partially integrated inside the crankshaft "nose", while its protruding part , with the clutch disc,

  are housed inside the drum-shaped flywheel.

  The axial dimension of the stopper therefore does not add to that of the flywheel.

Claims (6)

  1. Hydraulic stop for controlling a clutch fitted to a motor vehicle which is driven by an engine such as a heat engine, by means of a gearbox, this clutch being interposed between a free end portion ( 11), designated "nose", of the engine crankshaft (1), and an end portion of the input shaft of the gearbox (2) which is arranged coaxially in the extension of the crankshaft (1) , characterized in that said hydraulic stop (6,7) is partly housed inside a recess (13)   formed in the crankshaft "nose" (11).   2. Hydraulic stop according to claim 1, characterized in that it comprises an annular piston (7) guided in translation and immobilized in rotation on said end portion (21) of the input shaft (2) of the gearbox, as well as a sleeve (6) in the form of a cylindrical sleeve, integral with said shaft (2) and guided in rotation inside said recess (13), the annular piston (7) being adapted to slide axially inside the jacket (6), in one direction or the other, as a result of the supply or the escape of a liquid   hydraulic between these two elements.   3. hydraulic stop according to claim 2, characterized in that it comprises an elastic means (23), such as a spring, which constantly biases said piston (7), tending to move it in the direction of coupling of the clutch.   4. Clutch provided with a hydraulic stop conforming to one of   previous claims, characterized in that it comprises, on the one hand, a   flywheel (3) comprising a discoid flange (30) fixed on the crankshaft "nose" (11l), which extends in a transverse plane, perpendicular to the axis (X-X ') common to the crankshaft (1) and to the input shaft (2) of the gearbox, a cylindrical outer portion (31) centered on this axis (X-X '), and a flat annular part (4) fixed to this portion cylindrical outer surface (31), parallel and facing the external zone of said flange (30) and, on the other hand, a clutch disc (5) guided in translation and immobilized in rotation on said portion of end of the gearbox input shaft (2), this disc (5) being interposed between said discoid flange (30) and said planar annular part (4), against   which it can be applied and joined together under the effect of an axial pressure.   5. Clutch according to claim 4, characterized in that the application of the disc (5) against said planar annular part (4), under the effect of a   axial pressure, is produced by means of a diaphragm (8) which is integral in rotation with the flywheel (3), and the deformation of which is governed by the translational movement of said annular piston (7).   6. Clutch according to one of claims 4 or 5, characterized in that said stopper is supplied with hydraulic fluid by one or more   channels (200, 201) drilled in the input shaft (2) of the gearbox.