FR2572032A1 - CLUTCH DEVICE FOR A MOTOR VEHICLE - Google Patents

Abstract

THIS DEVICE IS OF THE TYPE INCLUDING A FRICTION CLUTCH 3 WITH A DISENGAGEMENT DEVICE 9, A SERVOMOTOR 15, 17, A CLUTCH CONTROL DEVICE 21, 23, AN ENGINE SPEED SENSOR 27, A TRANSMISSION SPEED SENSOR 29 AND A SKATING REGULATION CIRCUIT THAT CONTROLS THE SERVOMOTOR 15, 17, AS A FUNCTION OF THE ENGINE SPEED DETECTED AND THE GEARBOX INPUT SPEED DETECTED, IN RELATION TO THE POSITION OF THE RELEASE DEVICE 9 DETERMINED BY THE CONTROL DEVICE CLUTCH 21, 23 SO THAT THE DIFFERENCE IN SPEED BETWEEN THE ENGINE SPEED AND THE GEARBOX INPUT SPEED IS SENSITIVELY EQUAL TO A PREDETERMINED SPEED DIFFERENTIAL. AN AVERAGE TRAINING CIRCUIT PRODUCES AN AVERAGE VALUE SIGNAL CORRESPONDING TO THE AVERAGE OVER TIME OF THE DIFFERENCE BETWEEN THE DETECTED ENGINE SPEED AND THE DETECTED GEARBOX INPUT SPEED, RELATED TO A CONSTANT TIME INTERVAL, AND THE SKATING REGULATION CIRCUIT SERVES SERVOMOTOR 15, 17 AS A FUNCTION OF THE AVERAGE VALUE SIGNAL.

Description

"Clutch device for a motor vehicle"

  The invention relates to a clutch device for a vehicle

  motor, of the type comprising a) a friction clutch with a disengaging device whose position determines the torque that can be transmitted by the friction clutch, b) a servomotor which positions the disengaging device, c) a control device clutch which selectively determines the position of the disengagement device between a fully disengaged disengagement position and a fully engaged clutch position, d) an engine speed sensor which detects the engine speed, e) a speed control sensor. boot which detects the speed of entry of the gearbox, f) a slip control circuit which controls the servomotor, as a function of the detected engine speed and the gearbox input speed

  detected, relative to the position of the disengaging device deter-

  undermined by the clutch control device, so that

  the difference in speed between the engine speed and the engine speed

  of the box is substantially equal to a regime differential

predetermined.

  German Patent Application P 33 30 332 discloses a device

  clutch for a motor vehicle o, in order to dampen the vibra-

  twisting and reducing unwanted noise, the position of the disengagement device is, by means of a slip regulation circuit, controlled according to the engine speed and the engine speed.

  input of the gearbox so that the clutch engages

  even in the engaged state with a predetermined slip.

  The object of the invention is to configure a device for

  clutch, o a slip control circuit provides depending on the engine speed and the gearbox input speed a

  predetermined slip or a predetermined speed differential

  in such a way that the clutch device can respond to the operating states that appear during the operation of the motor vehicle,

  and at the same time the torsional vibrations and the operational noises

  have been reduced effectively.

  In the context of the invention, this object is achieved by the fact that an averaging circuit produces a signal of average value corresponding to the average time of the difference in speed between the detected engine speed and the engine speed. detected box input, ratio .. to a time interval of constant duration, and that the slippage control circuit slaves the servomotor as a function of the average value signal. The invention starts from the observation that the torsional vibrations and the operating noise of the clutch and the gearbox are due to the irregular rotation of the engine. During the working phase of each cylinder, the motor is strongly accelerated during a relatively low rotation angle compared to

  a complete rotation of the crankshaft, while turning to a

  Angular velocity substantially regular until the working phase of the next cylinder. These jolts cause torsional vibrations and a buzzing of the gearbox gears. The averaging circuit used in accordance with the invention produces an error signal reduced to a base value, which represents the angular velocity (which remains substantially constant) between the working phases of the different cylinders. This error signal slaves the actuator of the disengagement device, and allows regulation of the regular slip and free of parasitic vibrations. Advantages

  in particular for the operating states where the

  clutch already transmits the operating torque. Here we obtain a behavior where the clutch only skates during

  the working phases of the cylinders, while it does not slip

  not between work phases. In this way, we can now

  keep a low thermal stress on the clutch.

  With regard to the control device, it may be a conventional clutch pedal, which positions the disengaging device via a particular end member or by

  through the final member of the patient's control circuit.

  swimming. The arrangement may be provided so that the disengaging device is, in a conventional manner, operated directly

  from the clutch pedal via hydraulic cylinders

  transmitters and receivers, while the final body ensures

  it is a complementary positioning of the disengaging device with respect to the receiving cylinder of the hydraulic system which is situated on the side of the disengaging device. However, you can also

  replace the clutch pedal with an automatic clutch

  tick, which enslaves the final organ assigned to the clutch pedal.

  In a preferred embodiment, the servomotor is designed as a position servomotor, which adjusts the position of the disengaging device to a position determined by a position command signal. The servomotor is expediently enslaved both via the slip control circuit and through the control device, clutch pedal for example. The position command signals produced by the circuit

  skid control or, as the case may be, by the control device

  are appropriately standardized, so that the servomotor can alternatively be controlled by means of the device

  control (ie via the clutch pedal).

  ge), or via the slip regulation circuit.

  In this way, it is possible in this way to eliminate

  unwanted release of the disengaging device during switching.

  The slip regulation circuit is here disconnected when the slip set to the clutch pedal is greater than the predetermined slip value than the slip regulation circuit.

  indicates as to be respected.

  In a preferred embodiment, the training circuit

  averaging comprises two signal paths for signals which represent the difference in speed or which are used for

  form the diet difference. One of these trips includes an interest

  scratcher who performs the formation of the average. The other signal path has an amplification of 1, and transmits, while hardly modifying it, the signal representing the difference in speed at the output of the averaging circuit. The time constants of the two signal paths are significantly different. While the signal trgjet comprising the integrator has a high time constant, so that its output signal follows only slow changes in the speed difference signal, the other signal path has a low time constant, so that

  rapid changes in the speed difference signal appear-

  with amplification 1 at the output of the averaging circuit. When the averaging circuit is realized by means of an operational amplifier, the two signal paths are obtained by the different time constants of the two inputs. In particular, when training circuits of average

  from active components, saturation effects may appear

  within the skating regulation circuit, which delays the response of the circuit when a modification of its

  input signals. In order to prevent this phenomenon, a form of

  It is preferable to connect a limiter circuit to the integrator, which limits the output signals of the integrator to the

  proportional band of the latter. The limiting circuit should be

  band proportioneledecdene.Icovetqelciut n

  The controller is not limited to limiting the control range, but is also responsible for pre-setting the integrator during the operating phases when the servomotor is slaved from the control device. While the control device is effective, as already mentioned above, the slippage control circuit is disconnected. Despite this, the integrator follows the signals representing the engine speed or the input speed of the engine.

  in order to be able, when transmitting the guidance of the servo

  motor from the control device, connect the control circuit

  skating with the least delay and the least skipping

signal possible.

  Whereas this transmission of the guide of the servomotor can

  be accompanied by a sudden change in the position of the

  positive release which is determined by the control device

  (ie by the clutch pedal), and therefore a sudden change

  skating, a preferred embodiment provides

  that the limiter circuit can be controlled according to the posi-

  the clutch pedal or the position of an accelerator pedal.

  in such a way that the integrator can be blocked from

  predetermined values of its output signal according to the posi-

  the clutch pedal and / or the accelerator pedal. The output signal of the integrator can thus be set to values which reduce the predictable slip error during a modification.

of these pedal positions.

  In a preferred embodiment, the control circuit

  skating includes a patient value control circuit.

  which governs, as a function of the engine speed, the slippage set value which the skid regulation circuit must comply with. In this way, it is possible to ensure that the friction clutch operates with a predetermined slip only when this is necessary as a result of the construction mode of the engine-gearbox assembly of the vehicle. It is possible in particular

  to damp mechanical resonance points of the motor unit

  gearbox by resonating elevation of skating at the level of

  the resonance frequency. The patient value control circuit

  is necessarily designed in such a way that slip decreases when the engine speed increases, and in particular that it has fallen to zero

  at a speed where the clutch is usually already engaged. abstraction

  With the resonant elevations already mentioned, the slip is necessarily reduced to zero at a speed of between 2,000 and 2,600 rpm. This range of speed is generally

  below the speed at which maximum engine torque is obtained.

  wrong. When the friction clutch is engaged, the engine is idling and the gearbox is in neutral, it may occur due to the irregularity of the engine rotation,

  what is called a "clatter" of clutch or gearbox.

  The rattling can be prevented if, when the gearbox is in neutral, disengaging the clutch independently of the clutch control device, that is to say the pedal. The neutral position could be detected using a sensor provided on the

  gearbox; but this would require

relatively high.

  A second aspect of the invention, which can also be

  folded for other clutch devices than those described above.

  above, relates to eliminating the "idle click" described above without having to use a position feedback sensor.

neutral of the gearbox.

  For this purpose, there is provided a disengagement control which, by the in-

  a servomotor (which may be the servo

  the clutch control device), can disengage the clutch

  clutch independently of the clutch control device. The clutch control disengages the clutch when the speed of travel detected by means of a speed sensor is at the speed of movement of a pedestrian or when the vehicle is stopped, that simultaneously the sensor of gearbox mode that detects the gearbox input speed detects a gearbox speed that is greater than a predetermined rpm value lower than the engine idle speed, and that at the same time the control device of the clutch delivers a signal which, in the absence of the

  disengagement control, would have enslaved the clutch in the position of

  brayage. In the presence of these three conditions, the clutch is disengaged against the clutch condition of the control device.

  the clutch. The speed of entry of the gearbox which is over-

  minded in this context is chosen small enough that,

  when the clutch is engaged, under operating conditions

  Normally it can not appear in any of the reports of the box without it causing engine stall. It has been found that a vehicle speed of less than 3 km / h and an entry speed of

  gearboxes below 300 rpm were appropriate values.

  quats for the conditions of disengagement.

  The disengagement control necessarily comprises a memory which is stored in the presence of the disengagement condition, and which is

  again erased via the control device of the

  clutch when the latter produces on its side a position command signal causing the disengagement of the clutch. If for example the clutch pedal is moved to the disengagement position, the guidance of the final member is again transmitted from the clutch control to the control device of the clutch, since the memory is erased. Another aspect of the invention, which like the preceding one is also of interest to other types of motor vehicle clutches, concerns

  the control device of the clutch en'tapt that such. The clutch

  friction bearings for the production of high engine torque

  powerful clutch springs, which in turn require

  same important pedaling efforts to disengage the clutch.

  To keep the pedal forces at a relatively low level, mechanical lever drives or hydrauic transmission systems are used. However, the reduction of the pedal force is done at the expense of the pedal stroke, which

  elongates. This is the reason why another objective of the in-

  The invention is to propose a clutch device for a motor vehicle, where the stroke of the pedal can, with simple construction measures, be dimensioned essentially independently of the

  actuating force to be exerted on the measuring device

brayage.

  This can be done in a simple way by the fact that

  positive release is driven by a servomotor which can be positioned by means of an electrical position control circuit, whose setpoint information is provided by a position sensor

  which detects the position of the clutch pedal. An appropriate device

  electric generator, with a predetermined linear relationship

  born, changes the relationship between the position of the clutch pedal

  and the instruction information. so that the range of

  the clutch pedal which is decisive for the actuation of the clutch elongates with respect to conventional clutches, and can be shifted relative to the rest position of the clutch pedal. When the sensors of the position of the clutch are made in the form of potentiometers, the adapter device can be

  realized in the form of a characteristic of resistance not

  Neither of i potentiometer. However, the adapter device can

  also be realized in the form of an additional nonlinear circuit

  between the position sensor and the control circuit.

  position, diode resistance network for example.

  The following description explains examples of realization

  of the invention with the aid of the appended drawing, in which: FIG. 1 is a schematic representation of a device

  of a motor vehicle, with a view to reducing the

  Rotational gears and noises, the friction clutch can be used with a predetermined slip, even to transmit the torque required for the operation of the vehicle; Figure 2 shows diagrams of S slip as a function of engine speed nm; Figure 3 is a block diagram of a lug control circuit operable in the clutch device of Figure 1; Figure 4 shows a programming flowchart for a control logic of the circuit of Figure 3; Figure 5 shows a diagram that shows the average couple

  that can be transmitted by the clutch according to a tension of con-

  USoll sign determining the clutch position, to explain a limiter circuit which limits the output signal of an integrator provided in Figure 3; Figure 6 shows a circuit diagram of the integrator and limiter circuit of Figure 3; Figure 7 shows diagrams that show the actual position of the release device as a function of the pedal stroke, to explain a pedal stroke adapter device of the circuit according to Figure 1, and

  Figure 8 shows a circuit diagram of the adaptive device

pedal actuator.

  Figure 1 shows an internal combustion engine 1 of a vehicle

  motor-driven engine, which is coupled to a manual gearbox 5 through a friction clutch 3 type conventional disc. An accelerator pedal 7 controls in a manner not shown the power of the internal combustion engine 1. The clutch 3 is provided with a disengaging device 9 which, via a receiver cylinder 13 connected to a emitter cylinder 11, can be moved hydraulically between a clutch position fully engaging the clutch 3 and a disengagement position disengaging the clutch completely. The transmitter cylinder Il,

  and consequently the disengaging device 9, is positioned by an organization

  electrical final terminal 15, which is connected to a clutch control 19 via a servo control circuit 17. The control

  clutch 19 responds to position signals of a position sensor.

  23 mechanically coupled to a clutch pedal 21, and deli-

  1, the set member 15 is set to a position determined by the clutch pedal 21. In addition, a position sensor 25 is

  coupled to the final organ 15; this sensor delivers to the servo circuit

  regulation 17 of the actual position signals which correspond to

  the actual position of the disengaging device 9.

  The clutch control 19 includes a slip regulation circuit, which responds to an engine speed signal which is produced by means of an engine speed sensor 27 and which is proportional to the engine speed or to the speed instant angular (e), and. a box-entry speed signal which is generated by means of a box speed sensor 29 and which is proportional to the input speed or to the instantaneous angular speed (e) of the gearbox, and adjusts the final member 15 to a predetermined slip

  between the engine speed and the entry speed of the gearbox.

  tesses. The clutch control 19 also responds to a speed signal which corresponds to the running speed of the vehicle and which is supplied by a speed sensor represented at 31, detecting for example the speed of the gearbox output. as well as to a logic control signal which, by means of a switch 33 in the form of, for example, a threshold switch, is produced during the excursion of the accelerator pedal 7 from its position

rest.

  The skid control circuit raises, independently of the actuation of the clutch pedal 21, the slipping of the clutch 3 (that is to say the difference between the engine speed and the engine speed).

  gearbox input) to a predetermined slip value.

  when the slip of the clutch determined by the position of the clutch pedal 21 is less than the value predetermined by the slip regulation circuit. This slip, which is obtained even when the clutch is in operating state transmitter

  of torque, reduces torsional vibrations and noise from the

  clutch 3 and the gearbox 5 which are due to rotational irregularities of the internal combustion engine 1. As can be seen in Figure 2, the slip control circuit varies the

  predetermined slip value S as a function of the

  nmot engine. At low speed, the degree of irregularity is high, and

  as a result, the predetermined slip S is high. When the regime

  engine increases, S skating decreases to zero, skating

  being reduced to zero at a speed where the clutch 3 is, at the time of writing,

  normal vehicle, already engaged. FIG. 2 shows at 35 a typical slip / engine speed characteristic curve of the slip control circuit, which has a slip of about t at speeds in the vicinity of the engine idling speed,

  and reaches zero at a speed of about 2,200 revolutions per minute

  nute. In a large number of motor vehicles, mechanical resonances appear in the drive system, resonances that greatly increase the degree of irregularity and the production of noise at the resonant frequency. As shown at 37 for a resonance of the drive system at about 3,000 rpm, the slip characteristic curve of the slip control circuit can greatly elevate the slip in the vicinity of this resonance, and thus ensure a decrease in irregularity and noise production. In addition, the drive system can already be well enough amortized in ranges

  of engine speed determined on the basis of

  resonance so that the clutch slippage is useless in these ranges. FIG. 2 shows a characteristic slip curve 39 shown in dashed lines, where the slip is lowered to zero in a speed range 41 and then, as the speed increases,

  rises first, before falling back to zero.

  In practice, slip values (relative to the engine speed) of up to about 10% at the idle speed and at most 5% at about 1500 rpm were found to be

- sufficient.

  FIG. 3 shows in detail the clutch control 19, which, as already mentioned, delivers position setpoint signals to the servo regulation circuit 17 and to the final member 15

  connected to it, which is embodied in the form of an electric motor

  cudgel. The position sensor 25 is embodied as a po-

  tentiometer coupled to the electric motor; the position sensor 23 is also a potentiometer. which is connected to a voltage source

  and which is coupled to the clutch pedal. The servo-servo circuit

  tion 17 receives the position command signals through the

  a servo electronic switch 43, which is controlled by a control logic 45 which will be discussed in more detail later. The control logic 45 responds to the actuation of the clutch pedal and, upon actuation of the latter, switches the control switch 43 to a switching position 47 where the servo regulation circuit 17 is connected by the intermediate of a pedal stroke adapter circuit 49 to the position sensor 23 of the clutch pedal and controls the final member 15 (.et by

  following the position of the disengaging device) according to the posi-

the clutch pedal.

  For the regulation of the clutch slip, there is provided an integrator 51 whose output 53 is connected to the control switch

  43 and, through the control logic 45, is

  effectively mutated at a switching position 55 corresponding to the slip characteristic curve shown in FIG. 2. At the switching position 55, the servo regulation circuit 17 is

  exclusively controlled by position command signals from

  integrator 51, while the position command signals

  products based on the pedal are disconnected.

  The integrator 51 comprises a differential amplifier 57

  sensing a significant amplification at idle, amplifier whose output (which is the output 53 of the integrator) is connected

  via a capacitor 59 to the inverting input. The in-

  Inverter is connected via a control circuit

  of the slip value 61 at the output of a frequency transformer

  voltage 63, which receives at its input 65.pulse signals from the box input speed sensor 29. The frequency of this pulse signal is proportional to the input speed of the gearbox. The engine speed sensor 27 is connected to an input 67 of a frequency-voltage transformer 69. The transformer

  frequency-voltage 69 delivers to the non-inverting input of the ampli-

  differential voltage 57 a voltage which is proportional to the frequency

  a series of pulses provided by the speed sensor.

  motor 27. In doing so, the integrator 51 integrates, as a function of time, a signal corresponding to the difference between the engine speed and the box-entry speed signals, which signal corresponds to the

  instant slip of the clutch.

  In accordance with the desired slip characteristic curve, the regulation of the slip only takes place under predetermined operating conditions of the vehicle. For this purpose, a logic signal for slippage control is produced by means of an AND gate 71 when the engine speed is greater than a predetermined speed value nml and simultaneously the gearbox input speed is lower. at a predetermined speed value

  For this purpose, the AND gate 71 is connected to the frequency converter.

  A voltage step 69 via a threshold stage 73 responsive to the engine speed signals for speeds above nm1, and to the frequency-voltage transformer 63 through a threshold stage 75 reacting to the box input speed signals for

  diets lower than ng1. The predetermined engine speed value

  Nmi1 is lower than the idle speed of the engine, in order to be able to reduce also through I slip regulation the noises and vibrations of the clutch or the gearbox when, during the course of the vehicle , the

  engine speed drops to values below the idle speed.

  The nm value is for example at about 300 rpm. The pre-determined v1 regime of box entry ng1 is above the

  idle speed and preferably in a steady state range where the engine

  clutch is, under normal operating conditions, already engaged. A suitable speed value is approximately in the vicinity of or just below the maximum engine torque, at about 2,400 rpm, for example. With the above-mentioned speed values, the slippage control signal is thus produced at engine speed values higher than 300 rpm and box entry speeds below 2,400 rpm. The control logic 45 switches the control switch 43 to the switching position 55 according to other parameters which are explained later, when the engine or transmission governor is within the aforementioned limits, and the signal of

skating control is produced.

  The control of the clutch via the pedal is

  priority with regard to positioning by means of the control circuit

  skating. A comparator 74, which is connected by its inverting input to the pedal stroke adapter circuit 49 and by its non-inverting input to the output 53 of the integrator 51, provides

  the control logic 45 another control signal when the

  clutch plate is at a position where it provides a position command signal for a position of the disengaging device

  which is closer to the fully disengaged position than

  the skating regulation circuit. In this case, the control logic 45 switches the control switch 43 to the switching position 47, and the final control circuit 17 is guided by

  the position command signal produced according to the pedal.

  The switching of the guidance of the servo-regulation circuit 17 by the integrator 51 to the guidance as a function of the clutch pedal may give rise to problems when, due to the actuation of the clutch pedal, significant differences in speed appear.

  between the engine speed and the speed of entry of the gearbox.

  its, and that the integrator 51 is brought to saturation. If the integration

  If the converter 51 has reached the state of saturation, the reaction of the regulation circuit will be delayed until the integrator 51, following a gradual reduction of the difference in speed, returns to

  its entries in the proportional band. If the switch

  command 43 was switched to the switch position 55 while the

  The regulator 51 is in the saturation state, which would lead to incorrect positioning of the clutch. In order to prevent this behavior,

  an integrator circuit 77 has been connected to integrator 51 which will be explained

  in more detail later in Figure 6. The limiting circuit

  The driver 77 blocks the output voltage of the integrator 51 to

  located within the proportional band of the control circuit

  Slip loss occurs when the slippage control signal of the AND gate 71 fed to an input 79 is missing, and therefore slippage control through the control logic 45 and the control switch 43 is inefficient. At an input 81, a control signal which represents the excursion of the acceleration pedal (7 in FIG. 1) from its rest position can also be supplied to the limiter circuit 77. For this purpose, the input 81 is connected via a threshold stage 83 to the switch 33 of the accelerator pedal. The limiter circuit also blocks the

  the output voltage of the integrator 51 to a value within the

  proportional band when, in the presence of the slip control signal, the acceleration pedal is not actuated. Finally, the limiter circuit 77 receives at an input B5 a signal representing the rest position of the clutch. For this purpose, the input 85 is connected

  through a threshold switch 87 to the position sensor

  23 of the clutch pedal. In the presence of a control signal representing the rest position of the clutch, the limiter circuit 77 reduces the regulation range of the integrator 51 in the disengagement direction. When the vehicle is stationary and the transmission is in neutral, there is a so-called "rattling" of

  the clutch, since in this operating state, the clutch pedal

  clutch is usually not depressed, and therefore the clutch drives gearboxes that almost always have latching synchronization. In order to eliminate this phenomenon, the clutch control 19 disengages the clutch when the vehicle is at

  stop and that the gearbox is in neutral.

  The neutral position of the gearbox is controlled without additional sensor placed on the gearbox, depending on the speed of the gearbox, the speed of the vehicle and the position of the clutch pedal. For this purpose, the speed sensor 31 is connected

  at an input 89 of a frequency-voltage transformer 91 which transmits

  form the series of pulses provided by the speed sensor 31 into a voltage signal proportional to the frequency (proportional to the

  speed) of this series of pulses. A threshold switch 93 furnishes

  Nitre a first control signal when the vehicle speed is lower than a speed located at pedestrian movement speeds - less than 3 km / h for example. A second signal of

  command is, by means of a threshold switch 95 connected to the trans-

  frequency-voltage trainer 63, produced when the transmission speed of the gearbox is greater than a second predetermined speed value n2 The speed value ng2 is dimensioned such that it can not, when the clutch is engaged, appear below the running speed detected by the threshold switch 93 in any of the positions of the box links, with the exception of

  from the neutral position. The value of regime ng2 is thus also

  below the engine idling speed, and preferably corresponds to the nm1 regime value. An adequate value for ng2 is for example 300 rpm. As the third control signal for the detection of the neutral position, the signal-produced by the threshold stage 87 is used, which signal represents the rest position of the clutch pedal. The three control signals are brought to an AND gate 97 which, in the presence of the three conditions, and therefore when the gearbox is in neutral, loads a memory 99 made in the form of a rocker. The output Q of the memory 99

  control, via the control logic 45, the communication

  43 to a switching position 101, where a voltage source 103, in the form of, for example, a potentiometer, delivers a position command signal to the servo regulation circuit 17, which slaves the final device 15, and consequently the clutch 3, in the disengaged position. The memory 99 keeps the clutch 3 in the disengaged position until it is reset. The reset signal is generated by a threshold switch 105 connected to the sensor

  position 23 of the clutch pedal when the foot pedal is

  clutch is moved to its disengaged position. When depressing the clutch pedal, the memory 99 is erased, and the switch 43 is simultaneously switched, via the logic of the clutch pedal.

  control 45, from the switching position 101 to the switching position

  47. At the switch position 47, the clutch can now be

  not be engaged through the clutch pedal.

* Figure 4 shows the programming flowchart of the software

  45, as it can for example be achieved using switches and comparators. The disengagement condition for the neutral position has priority over the actuation of the clutch via the clutch pedal or the clutch pedal.

  integrator 51. If the disengagement condition is present, the communi-

  The controller 43 is switched to the switch position 101, and the clutch is disengaged. If the disengagement condition is not present, it follows from the immediately lower priority, the control concerning compliance with the skating conditions. If slip conditions are not present, for example if the AND gate slippage control signal 71 is absent, the control switch 43 is switched to the switching position 47, and the clutch is controlled by depending on the position of the clutch pedal. If slip conditions are present, it is checked, according to the next lower priority, whether it is the position command signal provided by the clutch pedal or

  the one provided by the integrator that generates the most important skating

  that is to say, that represents a position of the device of de-

  clutch closer to the disengage position. If the guidance of the servo regulation circuit 17 is to be carried out by the clutch pedal, the control logic 45 switches the control switch 43 to the

  switching position 47. If the servo regulator circuit

  17 must be done by integrator 51, the

  control 43 is switched to the switching position 55.

  FIG. 6 shows in detail the integrator 51, the slip control circuit 61 and the limiter circuit 77. The inputs of the differential amplifier 57 of the integrator 51 are

  connected to the frequency-voltage transformers 63, 69 via

  series resistors 107, 109. At the non-inverting input,

  a capacitor 111 connected to the ground has been connected, which determines jointly

  with the resistance 109 the time constant of the non-inverting input. The time constant is expected to be short enough that sudden changes in the motor speed n of the mastermem signal fed to the non-inverting input occur without significant delay at the output 53, with an amplification of 1. The resistor 107 determines jointly with capacitor 59 the constant of

  integrator integration time for integrating the differ-

  difference between the engine speed signal and the input speed signal

  of box. The integration time constant is significantly higher than

  than the time constant of the non-inverting input, so

  that the signal provides at output 53 an average value of the difference

  instantaneous speed of angular velocity between the rotation of the motor and the rotation of the input shaft of the gearbox, and that the average value can be followed by slow changes in the difference, which are due to slow modifications of the engine trimmer which was averaged over a revolution. The integrator 51 comprises between its inputs and its output two paths of

  signals, and it allows, in case of a rapid modification of the

  average motor, to make a quick adjustment, depending on the patient

  swimming, of the position. clutch, without any delays in

  the time due to the average formation characteristics of the inte-

  integrator. The slip value adjusting circuit comprises a preferably adjustable voltage source, which is here realized in the form of a potentiometer 113 and which is connected by means of a series resistor 115 which is also preferably adjustable , at

  the inverting input of the differential amplifier 57. The input

  The jug 57 is used as a summation point, so that

  tégrateur 51 integrates the difference between on the one hand the signal of the sum of the box input speed signal and the control circuit signal

  slip value 61, and on the other hand the

  engine. By means of the slip value adjusting circuit 61, the slip characteristic curve can be adjusted (FIG. 2), and in particular the engine speed value at which the slip can be adjusted.

must be zero.

  The slip value setting circuit 61 superimposes on the box input speed signal an offset voltage or a constant offset current (e) or, in other embodiments,

  changing according to the engine speed. Voltage or current-

  The offset is dimensioned so that it compensates for the gearbox speed signal at the engine speed where the slip must be zero. In the circuit according to FIG. 6, this means that a voltage must be set at the voltage source 113 which, like the voltage of the frequency-voltage transformer 63, is produced at the zero slip regime. The resistor 115 determines the rate of change with which the slip varies according to the

engine speed.

  The limiter circuit 77 is connected via a dielectric circuit

  viewfinder generator of polarization voltage 117, as well as the

  control unit 43 via a resistor divider circuit 117 at the output 53 of the integrator 51, preferably with a variable bias voltage. The limiter circuit 77 comprises a plurality of selectively serviceable reactive circuits 119, 121 and 123 which are each connected to the divider circuit 117, and whose

  output signals respond to the inverting input of the ampli-

  Differential circuit 57. The reactive circuits 119, 121 and 123 have an identical structure, so that it will suffice to decree the reactive circuit 119. The latter comprises a comparator 125, whose

  the non-inverting input is connected to the resistance divider circuit.

  117, and whose inverting input is connected to a bias voltage source 127, preferably variable. The output of the comparator

  is connected to the inverting input via a capacitor

  129. The time constant of the integrator thus constituted is less than that of the integrator 51. At the output of the compiler, an output resistor 131 leading to the ground and an

  resistor 133 leading to the inverting input of the differential amplifier

  57. The reactive circuit 119 is connected via a diode AND gate 135 to the inverting input, which is

  85 (FIG. 3) for the control signal representing the

  rest position of the clutch pedal. The reactive circuits 121 and 123 are connected via servocontrollable switches 137, 139 to the inverting input of the differential amplifier 57.

  control switches 137, 139 can be slaved by the inter ---

  intermediate inputs 79 and 81 of the limiter circuit 77.

  FIG. 5 presents with a curve 141 the typical appearance of the

  torque M transmitted by the clutch according to a tension of

  k USoll5011 which consumes the position command signal and is

  supplied to the servo-regulation circuit 17. AK denotes the entire state

  disengaged, and EK the fully engaged condition of the clutch. The

  reference 143 denotes the slip point of the characteristic curve.

  clutch, at which point the clutch begins transmitting a noticeable torque. While the position of the disengagement device can be modified, by means of the clutch pedal and in accordance with the position command signal Usoll, between the positions AK and EK,

  the limiter circuit 77 limits the maximum range of regulation of the in-

  tegrator to the position command signal range between

  the slip point 143 and the clutch position EK. In order to prevent

  the saturation phenomena of the integrator 51 and to accelerate the response of the regulation of the slip, the regulation range is

  reduced during a shift of the clutch pedal from its position

  rest. When the signal representing the excursion of the clutch pedal from its rest position is applied to the input 85 of the LED AND gate 135, the limit of the regulation range close to the disengagement position is raised by direction of the position

  clutch, as shown at 145 in FIG.

  The control switch 137 which is in the reaction path

  Reactive circuit circuit 121 is closed when its control input 142 receives a signal representing the missing slip signal of AND gate 71 (FIG. 3). The reactive circuit 121 then blocks the output signal of the integrator 51 to a fixed value 143 (see FIG. 5) located within the regulation range of the slippage regulation circuit. A similar process occurs for another fixed value 145 while the clutch continues to be open,

  when a signal is brought to a control input 147 (see FIG.

  6) of the control switch 139, which represents the present

  this of the slipping signal of the AND gate 71, as well as the simultaneous excursion performed by the accelerator pedal from its rest position. Whereas the value 143 is in the neighborhood of

  the clutch position, or is away from the position of clutch

  the order of magnitude of the skating value that must be

  the slip regulation circuit, the fixed value 145 is

  preferably located in the slip range of the clutch.

  The pedal stroke adapter circuit 49 shown in FIG.

  Figure 3 allows a largely variable adaptation of the characteristic curve.

  pedal stroke characteristic to the characteristic curve of the declutching device, which curve determines the torque transmitted by the clutch. FIG. 7 schematically shows, with the aid of a continuous line 151, the torque Mk transmitted by the clutch as a function of the pedal stroke, which designates the rest position as 0%;

  by 100% the fully depressed position of the clutch pedal.

  Once a dead stroke 153 has been overcome, the clutch torque transmitted decreases until reaching 155 of the disengaged position,

  to then continue to move on a safety run giving

  born 157. The clutch process takes place in the order of succes-

  reverse movement when releasing the clutch pedal, the reference

  reference 159 denoting the slip point o begins the transmission of torque by the clutch. The reference 161 designates the point of maximum motor torque. The range of pedal travel located between points 159 and 161 is the clutch slip range which is

  used to engage the clutch. The position of the patient range

  is, both as regards its position in relation to the posi-

  the clutch's rest ratio as its percentage width in relation to the total travel of the pedal, determined by the design mode

  mechanical or hydraulic device for controlling the clutch.

  The pedal stroke adapter circuit 49 allows a modification of

  nonlinear cation of the characteristic curve of the

  function of] a depedal path. Reference 163 represents

  short a characteristic curve o the slip range is elongated between a slip point 165 and the maximum engine torque point 167. The increase in the slip range allows a more sensitive clutchThe line in dots and points 169 represents a characteristic curve o the slippage range is generally shifted with respect to its position relative to the rest position of the pedal. The long dashed curve 171 represents a characteristic curve of the torque as a function of the pedal stroke where the slip range follows a non-linear curve, according to which the

  torque strongly changes with the pedal stroke to the

  the slip point, and only slightly in the vicinity of the maximum engine torque. Furthermore, the races 163, 169 and 171 show that it is possible not only to offset the slip point and the maximum engine torque point with respect to the pedal's rest position, but also to extend the dead travel when the clutch is engaged and the safety stroke when the clutch is disengaged,

  at the corresponding end positions of the pedal.

  FIG. 8 shows a simple embodiment of a pedal travel adapter circuit, with which linear bends with inflection points can be obtained, in accordance with curves 163 and 169. The circuit comprises a transformer stage of FIG. impedance 175 having a low output resistance, and

  input 176 receives the position signal from the sensor of

  23. At the exit of the conversion stage of

  i75, a divider circuit consisting of the resistors has been connected.

  17 and 181. The resistors 177, 179 and 181 are mutually connected.

  While the resistor 177 is connected to the output of the state of

  impedance transformation 175, and thus receives a voltage corresponding to

  laying at the position of the clutch pedal, the resistors 179 and 181 are connected to preferably adjustable voltage sources, respectively 183 and 185. In the exemplary embodiment shown,

  the voltage sources 183 and 185 are constituted by potentials

  meters mounted between ground and a service voltage source.

  Resistance 181 is carried out in the form of a division

  1, and more particularly here in the form of an adjustable potentiometer, and it delivers at its output 187 the position reference signal of the control circuit 17 which determines the position of the disengaging device. Two diodes with opposite poles 189,

  191 are connected in parallel with the resistor 177.

  The diodes 189 and 191 limit by their threshold voltages the voltage drop at the resistor 177, in which the current can, by the resistor 177, be modified linearly according to Ohm's law. The values of the resistors 177, 179 and 181, as well as the bias voltages of the voltage sources 183 and 185, are

  chosen so that the linear range coincides with the range of

  pedal pedaling. Upon reaching the slip point q ca's maximum motor torque point, the voltage drop at the resistor 177 reaches respectively the threshold voltage of one of the two diodes, and the current of: our-circuit which s' flows through the diode then bypasses the resistance 177. The voltage division ratio, seen from the output 187, is thus modified, and

  the slope of the characteristic curve of the posi-

  the pedal stroke is therefore changed accordingly.

Claims (22)

  Clutch device for a motor vehicle, comprising a) a friction clutch (3) with a disengaging device (9) whose position determines the torque that can be transmitted by the friction clutch (3), b) a servomotor (15, 17) which positions the disengaging device (9), c) a clutch control device (21, 23, 49) which selectively determines the position of the disengaging device (9) between a disengaging position fully disengaged and fully engaged clutch position, d) engine speed sensor (27) which detects engine rpm, e) gear rpm sensor (29) which senses the rpm of the gearbox (f) a slip control circuit (51, 61) which controls the servomotor (15, 17), based on the detected engine speed and the detected can input speed, with respect to the position of the device   declutching device (9) determined by the control device of the   clutch (21, 23, 49), such that the speed difference between the engine speed and the gearbox input speed is substantially equal to a predetermined speed differential, characterized by the fact that averaging (51) produces a signal of average value corresponding to the time average of the difference in speed between the detected engine speed and the detected box-entry regime, referred to a time interval of constant duration, and that the slip regulation circuit (51, 61) slaves the servomotor (15, 17) in accordance with the signal of average value.   Clutch device according to Claim 1, characterized in that the servomotor is designed as a position servomotor (15, 17), which adjusts the position of the disengaging device (9) to a position determined by a signal of position setpoint, and that both the control device (21, 23, 49) and the slip regulation circuit (51, 61) produce position command signals   for servocontrol of the position servomotor (15, 17).   Clutch device according to Claim 2, characterized in that a control circuit (43, 45, 73) compares the position command signals of the control device (21,   23, 49) and the slip regulation circuit (51, 61), and disconnected   for the position servomotor (15, 17) the position command signal of the slip regulation circuit (51, 61) when the position command signal of the control device (21, 23, 49) represents a position plus close to the declutching position that   the position command signal of the control circuit of the. pati- swimming (51, 61).   Clutch device according to Claim 3, characterized in that the control circuit (43, 45, 73) for the position actuator (15, 17) disconnects the position command signal from the control device (21). , 23, 49) when the position command signal of the control device (21, 23, 49) represents a position closer to the clutch position than the   position setpoint of the slip regulation circuit (51, 61).   Clutch device according to any one of the claims   characterized in that the averaging circuit (51) has two signal paths for the signals representing the speed difference, a signal path of which includes an integrator (57, 59) for averaging the signals. fluctuations in engine speed due to rotational irregularities, and has a time constant that is greater than the constant   time of the other signal path, and in particular equal to a multi-   ple of this last: Clutch device according to claim 5, characterized in that the averaging circuit (51) comprises a differential amplifier (57) whose inverting input is connected to its output via a capacitor (59) and receives by   via an input resistor (107) a proportional signal   the non-inverting input receives a signal proportional to the angular velocity of the motor via an RC circuit (109, 111), with a constant of time less than the time constant which   is effective at the inverting input.   Clutch device according to claim 5 or 6, characterized   characterized in that a limiter circuit (77) which limits the output signals of the integrator (57, 59) to the proportional band of this integrator   last, is connected to the integrator (57, 59).   8. Clutch device according to claim 7, characterized in that the limiter circuit (77), as a function of a signal representing the missing actuation of an accelerator pedal and / or a signal representing the active connection of the slip regulation circuit (51, 61), blocks the integrator (57, 59) at a predetermined value of its output signal when the accelerator pedal (7) is not actuated and the slip control circuit (51, 61) is active, or when the slip control circuit (51, 61) is not active.   Clutch device according to claim 7 or 8, characterized   characterized in that the limiter circuit (77) limits the position control range of the integrator (57, 59) to position values of the servomotor (15, 17) located between the clutch position and a position located at a slip point position representing the beginning of torque transmission by the clutch (3), and that the limiter circuit (77) is responsive to a signal which represents   positioning of the disengaging device (9) by means of the   control (21, 23, 49). at a position different from the clutch position and, according to this signal, limits the regulator range of the integrator (57, 59) to position values between the   clutch position and a position between the position of   clutch and skate point position.   Clutch device according to any one of the claims   tions, characterized by the fact that the regulating circuit   of the slip (51, 61) comprises a slip value control circuit (61) which changes the predetermined speed difference depending on the engine speed.   Clutch device according to Claim 10, characterized in that the slip value control circuit (61)   reduces to zero the predetermined regime difference when the engine increases.   Clutch device according to Claim 11, characterized in that the slip value control circuit (61) reduces to zero the predetermined speed difference in a range.   engine speed between 2,000 and 2,600 rpm.   Clutch device according to one of Claims 10 to 12, characterized in that the slip value control circuit (61) raises the predetermined speed difference in the resonance frequency range in resonance. mechanical   of the engine-gearbox assembly.   Clutch device according to any one of the claims   6 to 9 and 10 to 13, characterized in that the slip value control circuit (61) has two series resistors (107, 115), a first connection of each of these resistors being connected to the input inverter of the differential amplifier (57), the second connection of one of these resistors being connected to the gearbox speed sensor (29) and the second connection of the other resistor being connected to a voltage source (113). ), and that, at the engine speed o the predetermined speed difference is zero, the voltage source (113) and the gearbox speed sensor (29) produce currents identical to the second couplings of the two resistors in series.   Clutch device according to any one of the claims   tions, characterized by the fact that the regulating circuit   slippage (51, 61) comprises a control stage (71, 73, 75)   at the detected engine speed and at the can input speed   control stage which connects the control circuit of the   (51, 61) when the engine speed is greater than a first predetermined speed value which is itself lower than the engine idling speed and simultaneously the engine speed of entry.   gearbox is less than a second predetermined speed value   completed which is itself greater than the engine idling speed, and which disconnects the slip regulation circuit (51, 61) when the engine speed is lower than the first predetermined speed value or when the engine speed is less than the gearbox   is greater than the second predetermined speed value.   16. Clutch device according to claim 15, characterized in that the first predetermined speed value is in the vicinity of 300 rpm, and the second speed value.   predetermined in the vicinity of 2,400 revolutions / minute.   Clutch device for a motor vehicle, comprising a) a friction clutch (3) with a disengaging device (9) whose position determines the torque that can be transmitted by the friction clutch (3), b) a servomotor (15, 17) which positions the disengaging device (9)   c) a clutch control device (21, 23, 49) which selectively determines the position of the disengaging device (9) between a fully disengaged disengagement position and a fully engaged clutch position,   (d) an engine speed regulator (27) which detects the engine speed   tor, in particular according to any one of the preceding claims,   characterized by the fact that a vehicle velocity responsive speed sensor (31) is provided, which produces a first signal representing the stopping of the vehicle or vehicle speeds at the pedestrian velocity levels, which the control device of the clutch (21, 23, 49) produces, in the presence of its position command signal determining the position   clutch, a second signal representing this operating state   and that a clutch control (97, 99, 103) produces a position command signal slaving, independently of the clutch control device (21, 23), the servomotor (15, 17) in the disengagement position when the first and the second signal are present and the detected can input speed is greater than a predetermined speed value which is itself lower than idle speed of the engine.   Clutch device according to Claim 17, characterized in that the disengagement control (97, 99, 103) comprises   a memory (99) which is loaded in the presence of the condition   disengagement action and which keeps the servomotor (15, 17) in   disengagement action, and that the clutch control device   (21, 23), in the presence of its position command signal determined   the disengaging position, produces a third signal representing   both this state of operation and causes this signal to the memory (99) to clear the stored clutch condition. 19. A clutch device for a motor vehicle, comprising a) a friction clutch (3) with a disengaging device (9) whose position determines the torque that can be transmitted by the friction clutch (3), b) a servomotor (15, 17) which positions the disengaging device (9), c) a clutch pedal (21), d) a position sensor (23) coupled to the clutch pedal (21)   and controlling the servomotor (15, 17), in particular according to a certain   of the preceding claims,   characterized in that the position sensor (23) produces an electrical control signal representing the position of the clutch pedal (21), an electrical adapter device (49) is provided which establishes a predetermined non-linear relationship between the position of the clutch pedal (21) and the control signal, and   that the servomotor (15, 17) comprises a position control circuit   electrical control (17) which, via an electrically controlled end organ (15), adjusts the position of the disengaging device (9) to an established position as setpoint information by the signal control.   Clutch device according to Claim 19, characterized in that the position sensor (23) is designed as a potentiometer which, in order to form the adapter device,   has a nonlinear resistance characteristic.   21. Clutch device according to claim 19, characterized in that the adapter device (49) is designed as a diode resistance network 177, 179, 181, 189, 191),   and is mounted between the position sensor 23, and the control circuit. Position position (17).   Clutch device according to Claim 21, characterized in that the diode resistor network is constructed as a resistance divider circuit (177, 179, 181) and at least one diode and preferably two diodes with opposite poles (189, 19 1), are (are) mounted in parallel with at least one (177)   resistors of the resistance divider circuit (177, 179, 181).