FR2729196A1 - FRICTION CLUTCH - Google Patents

Abstract

The invention relates to a friction clutch. In this friction clutch for transmitting torque in a transmission section having an input part (2) driven by a motor and an output part (8) connectable to a shaft to be driven and an actuator (14) For engaging and disengaging the clutch, a torque to be transmitted produces the force determining the friction engagement for the clutch and the device (14) has a component (13) which can be driven by the part. clutch input and a second component (15) connectable to and separate from the clutch output portion. Application in particular to friction clutches used in motor vehicles.

Description

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  aulCU7T UO: 2snqUcsD rn; o ur "p uTnbL2qilnT a CTeiaXa C jpd aumos '.naqouur, pD a-oS ep a-DPCd.T PL eu, -Pue aea rnad TnD' ae: Due, ernied to an apessod -n In this invention, this is achieved by virtue of the fact that at least one of the following is provided in FIG. 1, FIG. 1, FIG. 1, FIG. 4, and FIG. of engagement of the friction clutch, a force determining the meshing by friction as a function of the torque to be transmitted by the friction clutch can be produced by means of the

  actuating device and that the actuating device

  for this purpose comprises a first component, which can be driven by the input part of the friction clutch, and a second component, which can be connected, from the drive point of view, to the output part of the friction clutch and can be separated from this part, these components cooperating to produce the engagement or closing force for the friction clutch. Therefore, in accordance with the invention, the torque transmitted by the friction clutch is used for

  produce an actuating force. This force of action

  which preferably causes a closure of the embra-

  friction shoe can be adjusted or controlled

  proportionally to the applied torque. The operating force or closing force of the friction clutch can therefore be adjusted by means of the actuating device so that it precisely prevents slippage between the inlet portion and the outlet portion of the friction clutch. the friction clutch. The actuating force applied by the actuator for the friction clutch can be produced simply by means of a relative rotation present between the inlet portion and the output portion of the friction clutch. In a particularly advantageous manner, the actuating device may have a device which converts the torque, which is to be transmitted or is present between the input part and the output part, into a

axial force.

  For the arrangement and operation of a friction clutch according to the invention, it may be particularly appropriate for this clutch to have a housing, which can be connected to the steering wheel of an internal combustion engine, a pressure disc which is locked in rotation but is axially movable relative to the housing, a coupling disc, which can be clamped between a friction surface of the pressure disc and a friction surface of the flywheel, as well as actuating means which act between the crankcase and the pressure disc, the clutch disc forming the output portion of the friction clutch. The driven portion of the clutch disc may be formed by a hub, which may be

  connected to the input shaft of a transmission. advantageously

  The friction clutch may have a means of

  designed in the same way as levers of multiplier-

  tion, by means of which the force required for closing the friction clutch can be applied to the friction clutch. For this purpose, the reduction levers can be loaded, at their radially inner part, by the actuating device,

  especially by its first component. The levers of

  tiplication can however be arranged internally from the radial point of view and possibly be interconnected by means of an annular portion, so that they directly form the first component, which cooperates with the second component to produce an axial force . Advantageously, the actuating means or the reduction levers may be formed by an annular component, which has individual radial arms. We know such an annular component by

  example according to German Patent 838,094.

  The gear levers may be pivotably mounted to the clutch housing and load the pressure disc at least out of the closure or when the friction clutch is closed. For the arrangement of the friction clutch, it may be appropriate for the reduction levers or gear lever component to be pivotally mounted relative to the housing by means of radially outer portions and load the pressure disc by means of zones located between these outer zones and the inner zones from the radial point of view. In many cases of application, however, it may be advantageous for the transmission levers to load the pressure disk by their radially outer zones and to be mounted so as to be able to pivot on the housing, by means of zones

  located further inside the radial point of view.

  For the operation and arrangement of the friction clutch, it may further be appropriate to subject the gear levers acting as clutch operating means, or the component forming these levers to a restoring force. acting in the direction of opening or closing the friction clutch. In the case of the use of an annular-shaped component to form the actuating means, this component can be made to present a

corresponding elasticity.

  It may be particularly advantageous for the actuating device to have a servomechanism which ensures that the power or external energy to be supplied for the actuating device and which is necessary for the establishment of the closing force of the actuating device. friction clutch, can be kept at a low value. This servomechanism can advantageously be arranged between the first component and the second component of the actuating device. The desired servomechanism can be produced for example by a ramp device, in which case at least one and preferably two components carry corresponding ramps. The servo action of the ramp device can be adapted to the respective application case, thanks to an appropriate choice of the slope angle of the ramps. The arrangement of the ramps may be such that, in the case of transmitting a torque from the input portion to the output portion of the friction clutch, a force closing the friction clutch is produced. It may also be advantageous if the ramps or the ramp device are arranged such that in the case of a torque transmission flow from the output portion to the clutch input portion, a force

  closing the clutch is produced. It can be particularly

  the use of the friction clutch in the drive section of a motor vehicle, that the ramp device is arranged in such a way that at least in the case where the When the actuation is activated, the ramp device causes the friction clutch to close both in the pushing operation and in the traction operation of the motor vehicle. The ramps, which act in the operation in thrust and in operation

  in traction, may have, depending on the case of application

  cation, at least approximately the same angle of climb or slope, or different slope angles, and in the latter case it may be appropriate for the ramp angle to be higher for

  thrust only for traction operation.

  A particularly simple arrangement of the embra-

  friction or actuation device can be guaranteed by the fact that the second component of the device

  the actuating device can be connected according to a drive connection.

  by means of a clutch to the output portion of the friction clutch or to the shaft connected to that portion, and may be separated therefrom. This clutch can also be arranged in the form of a friction clutch. Although this clutch can be arranged in the form of a clutch actuated by a pressurized medium, it is particularly suitable that it be designed in the manner of an electrically actuated clutch. In the case of the use of a clutch actuated by a pressurized medium, the latter can be activated for example pneumatically or hydraulically. In the case of the use of an electrically actuated clutch, the latter can be advantageously arranged in the form of an electromagnetic clutch. A particularly simple arrangement of the electrically actuable clutch can be obtained by virtue of the fact that this clutch has at least one non-rotating spool holder and an axially axially displaceable armor disc. The armature disk can be rotatably connected to the second component of the actuator, but can be moved axially, at least in a limited manner, relative to this component. The articulation of the reinforcing disk on the second component can advantageously be achieved by means of an element in the form of an elastic membrane or by means of resilient elements in the form of leaf springs. For the arrangement of the actuating device, it may further be advantageous that at least one disc can be frictionally engaged with the armature disc and locked in rotation with the output portion of the friction clutch. , is disposed axially between the armature disk and the fixed coil body. This disc serves as a clutch disc and a disc of

  brake. This clutch disc or brake disc and the disc

  that frame can rotate relative to the spool holder

or to the reel.

  For the operation and arrangement of the friction clutch, it may be particularly advantageous that the armature disk carries at least one permanent magnet which cooperates at least with the brake disc or the clutch disc. It may be particularly advantageous if the armature disk is formed by a permanent magnet or has permanent magnetism. Such an arrangement makes it possible to guarantee that permanently a meshing determined by friction or a definite possibility of torque transmission exists between the armature disc and the brake or clutch disc. This ensures that, also in the case of a non-energized coil and a relative rotation at least between the input portion and the output portion of the friction clutch, an actuating force, such as in particular a closing force, can be transmitted to the means for actuating the friction clutch. By means of this frictional engagement, a relative rotation between the first component and the second component of the actuating device can be obtained, so that the device, which is provided between these two components and which converts the applied torque into a force axial, produces a closing force for the friction clutch. The use of a reinforcing disk, which has permanent magnet characteristics, has, particularly in the case of the use of the friction clutch in the driving section of a motor vehicle, the advantage of in that even when the engine is stopped, the friction clutch can be used as a parking blocking device when a gear ratio is engaged. As soon as the tendency of a relative rotation between the driven shaft of the motor or the flywheel and the input shaft of the transmission exists, the clutch locks or closes due to the friction action between the armature disc and brake disc or clutch. Therefore, in the case of a corresponding arrangement of the ramp device and in the case where a report of the transmission is engaged, the vehicle can be blocked both against the descent and against the climbing a slope using the engine then used as a brake. The brake disk or the clutch disk of the disengagement device may advantageously be arranged so as to be fixed axially and without the possibility of rotation, on the shaft

  can be driven by the output part of the clutch

  friction. The second component of the actuating device is suitably rotatably mounted relative to the shaft drivable by the output portion of the friction clutch. This second component can therefore pivot at least in a limited manner with respect to the first component and also in a non-angularly limited manner with respect to the brake disk or the disk.

clutch and coil body.

  The friction clutch arranged according to

  the invention can be automated in a particularly

  simply so that this clutch can be used

  with semi-automatic transmissions or with trans-

  fully automatic missions. For this purpose, the clutch of the actuating device can be controlled by means of an electronic unit, which deals with the operating parameters of a motor vehicle. This can be achieved in a particularly advantageous manner in the case of the use of an electromagnetic clutch, since then only the current flowing in the coil of the clutch and which determines the amplitude of the meshing to friction, must be adjusted and controlled accordingly. Depending on the direction of circulation of the excitation current in the coil, the electromagnetic clutch can be closed or open or

  meshing by friction in the electromagnetic clutch

  that can be increased or reduced. This last point is advantageous especially in the case of the use of a reinforcing disc having permanent magnet characteristics since, as already mentioned, in the case of the use of such a disc Even in the case of a non-energized coil, a certain torque can be transmitted. Therefore, a magnetic field, directed in the opposite direction of the magnetic field of the armature disk, must be established by the coil, for the opening of the friction clutch. Instead of using a reinforcing disk having permanent magnet characteristics, it is also possible to use a disk, in particular a metal disk, which is repelled by a predetermined force against the disk

  brake or clutch disc of the actuating device

  is lying. This force can be obtained by means of accumula-

  of force and to this end, it is also possible to tighten elastic means which guarantee a transmission of torque between the reinforcing disc and the second component of the

actuating device.

  As already mentioned, in place of an electromagnetic clutch, it is also possible to use a clutch that can be actuated for example by way of

  hydraulic or pneumatic, for the device desen-

  in which case the adjusting member or the piston / cylinder unit can be controlled by means of a valve,

  which is operated via an electronic unit

  which deals with the operating parameters of a

  motor vehicle. Due to the arrangement according to the

  the action of the clutch actuation device, here

  also relatively low pressures are required

  to operate the friction clutch or to apply

  the force required to close the friction clutch. Other features and benefits of the

  present invention will emerge from the description given

  Hereinafter, taken in reference to the accompanying drawings, in which: - Figure 1 shows a friction clutch arranged according to the invention; FIG. 2 represents a partial unfolding of the ramp device of the actuating device when looking in the direction of arrow II in FIG. 1; and FIG. 3 represents the characteristic curve

  torque of the clutch of the actuating device.

  The friction clutch 1 shown in FIG. 1 has a housing 2, which is connected in a rotationally locked manner to a flywheel 3. The steering wheel 3 can be driven via the output shaft 4 of FIG. a motor not shown in detail. A pressure disk 5 is connected with rotational locking, but with possibility of axial displacement, to the casing 2. This connection is effected in a manner known per se by means of leaf spring elements 6. The friction linings 7 d a clutch disk 8

  can be clamped axially between the friction surface

  5a of the pressure disc 5 and the friction surface 3a of the flywheel 3. Between the friction linings 7 can be provided segments of packing springs, which perform a progressive establishment and a progressive removal of the torque that can be transmitted by the friction clutch 1. The clutch disk 8, which forms the output portion of the friction clutch 1, has a hub 9, which is rotatably mounted on the input shaft 10 of the transmission. The flywheel 3 and the pressure disc form substantially the input portion of the friction clutch 1. The friction clutch 1 further has actuating means 11 which, in the case of the illustrated embodiment , are constituted by elements 12 in the form of levers, which can be mounted so as to be pivotable on the housing 2, by means of their radially outer parts 12a, can be pushed by a component 13 of the device of actuating 14, by their radially inner portions 12b and load the pressure disc 5, by means of their parts 12c located between the outer portions 12a and the inner portions 12b. The levers 12 therefore act as gear levers, which reinforce the axial force applied by the actuator 14 in the parts 12b so that the closing force of the friction clutch 1 is equal.

  to a multiple of this axial force or force of action-

  is lying. The levers 12 can be advantageously assembled

  in the form of an annular component, which simplifies the assembly of the friction clutch. Such an annular element is known from the German patent

838 094 already mentioned.

  The actuating device 14 has a

  first component 13, which can be driven through

  1 of the input part of the friction clutch 1 and by the actuating means 11 locked in rotation on the casing 2, as well as a second component 15 which can be connected in a driving connection to the part of output or disc 8 of the friction clutch and can be separated. The two components 13, 15 can rotate in a limited manner with respect to each other. The actuating device 14 has a device 16, which converts the torque to be transmitted by the friction clutch 1, into an axial force, which, in the exemplary embodiment shown, comprises a ramp device 17, which is disposed between the two components 13 and 15. As can be seen in particular in FIG. 2, in the exemplary embodiment, ramps 13a, 15a are provided on the first component 13 as well as on the second component 15. bearing in the form of balls 18 being disposed between these ramps 13a, 15a. According to an embodiment not shown, also only one of the two components 13, 15 may comprise ramps

cooperating with the balls 18.

  The device 16 or the ramp device 17 acts in the manner of a servomechanism, which produces an axial force amplification. This amplification depends

  the angle of inclination or rise of the ramps 13a, 15a.

  The arrangement of the friction clutch 1 or the actuating device 14 is such that the ramp device performs, at least during the transmission of a torque by the drive shaft 4 to the driven shaft 10 , a closing or engagement of the friction clutch 1. In addition, the ramps 13a, 14a, which rise in both directions of rotation, make it possible to obtain that not only in the case of traction operation but in the case of operation in thrust, we can get

  Clutch friction clutch 1. How does it work?

  traction occurs when the torque is applied via the shaft 4. The push drive is present when the application of torque

  is carried out via the shaft 10.

  The second component 15 can be connected by means of a clutch 19 to the shaft 10 with locking in rotation to the driven portion 8 of the clutch and can be separated from this

  tree. In the exemplary embodiment shown, this embra-

  Yage 19 is arranged in the form of a friction clutch,

  and this in the manner of an electrically operated friction clutch

  geometrically. The connecting device, which is formed by an electromagnetic clutch 19 and is disposed between the second component 15 and the shaft 10 has a frame disk 20, which can be brought into frictional engagement with a brake disk or brake disk. clutch 21, which is mounted on the shaft 10 with locking in rotation and axial locking. The reinforcing disk 20 is axially displaceable and rotatably locked to the second component 15. This rotational connection can be effected by means of a membranous component or by means of elements in the form of leaf springs, which are respectively connected by a rotationally locked connection to the two components 15 and 20. On the side, facing away from the armature disc 20, the brake disk or clutch 21 is arranged a coil or a spool holder 22, which is locked in rotation and preferably is locked axially for example on the casing 23 of the transmission, partially shown. As can be seen in FIG. 1, there is no direct contact between the coil carrier 22 and the brake or clutch disk 21. The brake or clutch disk 21 is constituted by a magnetizable material. This brake or clutch disk 21 is isolated, with respect to this shaft, which

  door, by an interlayer 24.

  Advantageously, the armature disk 20 may present at least partially a permanent magnetism. For this purpose, the armature disk 20 may carry at least one permanent magnet or it may consist substantially completely of a material having permanent magnet properties. In the case of the use of a reinforcing disk 20 having at least one residual magnetism, it can be certain that even in the case where the coil 22 is not supplied with current, there is a certain frictional meshing or a frictional engagement defined between the armature disc 20 and the brake or clutch disk 21. This frictional engagement ensures that even in the case of a stationary motor vehicle, the engine being stopping and a speed being engaged, a closing of the friction clutch 1 is possible. This is guaranteed by the fact that in the case of a tendency to a relative rotation between the two shafts 4 and 10, the friction moment, which exists between the two components 20 and 21, makes a relative displacement between the two components 13 and 15, with the further effect that an axial force causing closure of the friction clutch 1 is applied to the inner portions of the actuating means 11, by

  via the ramp device 17.

  At least during the commissioning of the motor vehicle, the coil 22 can be charged by a direct current, which causes the establishment of a magnetic force flow which, for a corresponding direction of the current, attracts the disk of reinforcement 20 towards the coil so that the meshing by friction between the two components 20 and 21 is increased. The intensity of the frictional engagement between the components 20 and 21 depends on the intensity of the excitation current. Thanks to the inversion of the excitation current, the coil 22 can also realize an axial discharge of the armature disk 20, which has the effect that the meshing by base friction, present due to the magnetization of the disk 20 or 21. As soon as this frictional engagement is eliminated or reaches a very low value, an opening of the transmission occurs, for example for the activation of the transmission. friction clutch 1. For this purpose, the actuating means 11 are loaded

  by a force in the sense of disengaging the embra-

  1, which has the effect that the first component 13 pushes the ramp device 17 back into the

  initial or median position shown in Figure 2.

  This position corresponds to the position of the lever 12, which is characterized by "A" in FIG. 1. The second component 15 is mounted so as to be rotatable, by means of a bearing 25, with respect to the shaft 10 or to the brake disk 21 and the coil 22. The actuating force is received via the bearing 25 and, for example as shown, is transmitted to the shaft 10, which retransmits again, via of the landing, the

  actuating force to the housing 23 of the transmission.

  The intensity of the excitation current for the coil 22 is controlled by means of an electronic unit 26, which processes various operating parameters. The operating parameters processed by the electronic unit can be formed for example by quantities representing the activation position of the

  transmission and the operating state of the transmission.

  Similarly, one can take into account variables, which represent the state of actuation of the brake of the vehicle

  automotive and / or engine load status.

  The return force, which acts on the actuating means 11, in the direction of uncoupling of the friction clutch 1 can be advantageously produced directly by the actuating means 11 made under

  the shape of an elastic component. The means of action

  may therefore be formed by an elastic membrane-shaped component which causes an opening of

  the friction clutch 1, in the unloaded state.

  Figure 3 shows the characteristic curve

  torque moment-current excitation of the clutch 19.

  As can be seen, a base moment 27 can be transmitted through the clutch 19 when the coil 23 is in a non-excited state. This base torque 27 is guaranteed by the base friction meshing existing between the two components 20 and 21. In the case of a corresponding power supply of the coil 22, the

  moment that can be transmitted by the clutch 19 increases.

  During a reversal of the direction of the current, the basic frictional meshing between the two components 20 and 21 is reduced so that the moment that can be transmitted between these two components decreases and that, for a corresponding intensity of the current, this torque is completely removed under the effect of the spacing of the armature disc relative to the disc 21. Thus it is also possible to obtain an opening of the friction clutch before the engine starts, and this also when transmission ratio is engaged and that the transmission section

is eventually tight.

  Instead of an electromagnetic clutch 19 we

  could also use, as an auxiliary clutch

  such a magneto-rheological clutch. It may be particularly appropriate for the clutch to be arranged in such a way that the magnetorheological liquid is subjected to the action of permanent magnets, so that, in the case where the clutch is not supplied with current, this clutch is virtually closed and therefore can transmit torque so that this clutch can

  assume a parking blocking function. The magnetic field

  The permanent magnet (s) can be reduced or eliminated by applying a current so that the moment that can be transmitted during the clutch can then be reduced or completely eliminated. Such a solution has the advantage that no friction oscillation can appear inside the auxiliary clutch. Such friction oscillations can be detrimental due to the high reinforcement produced by the servomechanism since they influence the modulation capability of the torque

  be transmitted from the main clutch.

  The invention is also not limited to

  the embodiment of the description. On the contrary,

  many changes and modifications can be made to the invention from the point of view of elements, configurations and / or materials and combinations of such elements without

depart from the scope of the invention.

Claims (26)

  A friction clutch for transmitting a torque in a transmission section, which includes an input portion, which can be driven by the output portion of a motor, an output portion which can be connected to a tree to be trained, and a   actuating device for switching on and off   characterized in that a force determining the meshing by friction as a function of the torque to be transmitted by the friction clutch can be produced by means of the actuating device and that the actuating device comprises for this purpose a first component, which can be driven by the input part of the friction clutch, and a second component, which can be connected, from a drive point of view, to the output part of the clutch to   friction and can be separated from this part.   2. Friction clutch according to claim 1, characterized in that the actuating device comprises a device   converting the applied torque into an axial force.   3. Friction clutch according to one of claims 1 or 2,   characterized in that it comprises a housing, which can be connected to the flywheel of an internal combustion engine, a pressure disc which is locked in rotation but is axially movable relative to the housing, a clutch disc, which can be clamped between a friction surface of the pressure disc and a friction surface of the flywheel, as well as actuating means which act between the housing and the pressure disc, the clutch disk forming the part   output of the friction clutch.   4. Friction clutch according to any one of   Claims 1 to 3, characterized in that the shaft, which can be connected to the   output part of the friction clutch, is the input shaft of a transmission. 5. Friction clutch according to any one of   Claims 1 to 4, characterized in that it has means   actuators arranged in the manner of a gear lever.   6. Friction clutch according to claim 5, characterized in that the gear levers can be loaded by the actuating device, at their inner portion of the radial point of view.   7. Friction clutch according to one of claims 5 or 6,   characterized in that the gear lever is pivotally mounted to the clutch housing and load axially the pressure disc.   8. Friction clutch according to any one of   Claims 1 to 7, characterized in that the actuating device has a servomechanism.   9. Friction clutch according to claim 8, characterized   in that the servomechanism has a ramp device.   10. Friction clutch according to any one of   Claims 1 to 9, characterized in that the servomechanism is provided   between the component, which can be driven by the input portion of the friction clutch and, the component that can be connected to the part of   output of the friction clutch, the actuating device.   11. Friction clutch according to any one of   Claims 1 to 10, characterized in that the ramp device   produces a force, which closes the friction clutch, in the case of torque transmission from the input portion to the output portion of the friction clutch.   12. Friction clutch at least one of the claims   preceding, characterized in that the ramp device produces a force which closes the clutch, in the case of a torque transmission   from the output portion to the input portion of the clutch.   13. Friction clutch according to any one of   Claims 1 to 12, characterized in that in the case of the use of   clutch in the transmission section of a motor vehicle, the ramp device causes, at least when the actuating device is activated, a closing of the friction clutch both during the pushing operation and during the   traction operation of the motor vehicle.   14. Friction clutch according to any one of   Claims 1 to 13, characterized in that the second component of   actuating device can be connected in a driving connection to the output portion of the friction clutch, by means of a clutch and   can be separated from this part.   15. Friction clutch according to claim 14, characterized   in that the clutch also forms a friction clutch.   16. Friction clutch according to one of claims 14 or   , characterized in that the clutch is an electrically actuated clutch. 17. Friction clutch according to any one of   Claims 14 to 16, characterized in that the clutch is a electromagnetic clutch.   18. Friction clutch according to one of claims 16 or   17, characterized in that the electrically actuable clutch comprises a non-rotating spool holder and a disc   armature can have a limited axial displacement.   19. Friction clutch according to claim 18, characterized in that the reinforcing disk is rotatably connected to the second component of the actuating device, but in such a way as to   to be able to move axially with respect to the latter.   20. Friction clutch according to one of claims 18 and   19, characterized in that the reinforcing disk is connected, in a rotational drive connection, to the second component via an elastic membrane-shaped element or via   resilient elements in the form of leaf springs.   21. Friction clutch according to any one of   Claims 18 to 20, characterized in that the armature disk carries at least one permanent magnet.   22. Friction clutch according to any one of   Claims 18 to 21, characterized in that the reinforcing disk is formed by a permanent magnet.   23. Friction clutch according to any one of   Claims 14 to 22, characterized in that a disk which can be   caused to frictionally mesh with the armature disk and rotatably connected to the output portion of the friction clutch,   is provided axially between the armature disc and the fixed spool pin.   24. Friction clutch according to claim 23, characterized in that the disc is mounted so as to be fixed axially and without the possibility of rotation on the shaft which can be driven by the output of the friction clutch.   25. Friction clutch according to any one of   Claims 1 to 24, characterized in that the second component of the   actuating device is rotatably mounted relative to the drivable shaft with respect to the output portion of the friction clutch.   26. Friction clutch according to any one of   Claims 1 to 25, characterized in that the clutch of the device   The actuating device can be controlled by means of an electronic unit, which processes the operating parameters of a motor vehicle.