FR2865516A1 - Transmission`s vibration filtering method for motor vehicle, involves applying electromagnetic torque to rotor for modifying natural frequency of cylinder, and adapting frequency to frequency of vibrations transmitted by vibration damper - Google Patents

Abstract

The method involves determining instantaneous acceleration of a flywheel and a rotor (42) of a cylinder. Current intensity of a power supply (48) of an electromagnetic unit is calculated based on the acceleration and inertia of the rotor to apply electromagnetic torque to the rotor, to modify natural frequency of the cylinder and to adapt the frequency to frequency of vibrations transmitted by a vibration damper (22) to a driven shaft. An independent claim is also included for a device of filtering vibrations in a transmission of a motor vehicle.

Description

The invention relates to a method and a device for filtering

  vibrations in a transmission between a motor shaft and a driven shaft, in particular for a motor vehicle, of the type comprising an "active" filter associated with the driven shaft which is, for example, the input shaft of a gearbox .

  Rotational vibration filtration devices comprising a mass coupled elastically to a rotating shaft are already known. Such a device, called a drummer, filters well a vibration frequency corresponding to the natural frequency or resonant frequency of the mass-spring system of the drummer, but on the contrary amplifies the vibrations at frequencies close to the natural frequency.

  "Active" systems have also been proposed, for example in document FR-A-2,658,888, which have a constitution similar to that of an electric motor controlled so that the torque provided by this motor comes in opposition to the vibration to be filtered for a given range of rotational speeds. These devices have the disadvantage of consuming a relatively large electrical power.

  Document FR-A-2 824 374 also discloses an active beater, in particular for a motor vehicle transmission, which is associated with the driven shaft of the transmission and which acts in addition to a main torsion damper. arranged in a conventional manner between the motor shaft and the driven shaft. In this case, the electrical power consumed by the filtration device is relatively low, for example of the order of a hundred watts, and the mixer can be used as an electric motor to provide additional engine torque on the driven shaft, and also as a recuperator of energy during braking.

  The present invention particularly relates to improvements and developments of the active drummer described in this prior document.

  It proposes a method for filtering vibrations in a transmission between a motor shaft and a driven shaft, in particular for a motor vehicle, the transmission comprising at least one flywheel secured to the drive shaft and a torsion damper, as well as a drummer comprising a rotor rotatably mounted around the driven shaft, a stator, electromagnetic means mounted on the stator and on the rotor and connected to a power supply, and elastically deformable means for connecting the rotor to the shaft conducted, characterized in that it consists in: - determining the instantaneous acceleration of the flywheel and / or the instantaneous acceleration of the rotor of the beater, - and calculating the intensity of a power supply current of said electromagnetic means from said instantaneous acceleration and the inertia of the rotor to apply to the rotor an electromagnetic torque which is added to the restoring torque exerted on the rotor by its elastically deformable means of connection to the driven shaft and which is substantially in phase or in phase opposition with this restoring torque, in order to modify the natural frequency of the beater and adapt it to the frequency of the vibrations transmitted by the the torsion damper to the driven shaft.

  This method has the advantage of consuming little energy since the beater acts as an electric motor on one half-oscillation period and as a brake on the other half-oscillation period, so that the average consumed current is low. and due to the losses, while allowing an effective damping of the vibrations in the low rotational speeds, in particular of 800-1000 revolutions per minute at approximately 1600 revolutions per minute.

  According to another characteristic of the invention, this method consists of determining the electromagnetic torque applied to the rotor from the product of the inertia and the instantaneous angular acceleration of the rotor of the mixer.

  According to another characteristic of the invention, the electromagnetic torque applied to the rotor is determined from the product of the rotor inertia and the instantaneous angular acceleration of the flywheel.

  In another variant of the invention, this method consists in determining the electromagnetic torque applied to the rotor from the product of the inertia of this rotor and its delayed angular acceleration.

  One can of course determine the angular accelerations from the measured angular positions of the flywheel and the rotor, and a double bypass.

  When the electromagnetic torque applied to the rotor is determined from the delayed angular acceleration of the rotor, the delay corresponds to the offset of 90 which exists between the speed and the acceleration at the frequency of the harmonic 2.

  Conveniently, the electromagnetic torque applied to the drummer rotor can be determined from measurements of the instantaneous angular position of the flywheel and / or those of the drummer rotor and of pre-stored value tables.

  Moreover, the method according to the invention is further characterized in that it consists of using the mixer to filter the vibrations outside the transmission ratio changes and to charge a capacitor of high capacity, the energy stored in the capacitor being restored for the synchronization of the rotational speeds during each gear change.

  Alternatively, the method according to the invention consists of separating the drummer from the driven shaft during transmission ratio changes.

  This avoids increasing the inertia of the driven shaft, which is generally formed by the input shaft of a gearbox, during transmission ratio changes, which facilitates synchronization and interconnection during these changes.

  The invention also proposes a device for filtering vibrations in a transmission between a driving shaft and a driven shaft, comprising at least one flywheel secured to the driving shaft, a torsion damper and a beater comprising a rotor mounted on a shaft. rotation around the driven shaft, a stator, electromagnetic means mounted on the stator and on the rotor and connected to a power supply, and elastically deformable means for connecting the rotor to the driven shaft, this device being characterized in that it also comprises: means for determining the instantaneous acceleration of the flywheel and / or the instantaneous acceleration of the rotor of the beater, and means for controlling the electric power supply of the electromagnetic means of the beater , said control means comprising calculation means for determining from the inertia of the rotor and its instantaneous acceleration or that of the flywheel the instantaneous value of the intensity of the supply current of the electromagnetic means for applying to the rotor an electromagnetic torque which is added to the restoring moment exerted on the rotor by its elastically deformable means of connection to the driven shaft and which is substantially in phase or in phase opposition with this restoring torque, in order to modify the natural frequency of the beater and adapt it to the frequency of the vibrations transmitted by the torsion damper to the driven shaft.

  According to other features of the invention, this device also comprises means for measuring the instantaneous angular position of the flywheel and means for measuring the instantaneous angular position of the rotor of the beater, which are connected to the calculation means. precipitated, for example to the engine control computer of the vehicle.

  In a particular embodiment of this device, the electromagnetic means of the mixer comprise conductive windings, for example carried by the stator, which are connected to a charging circuit of a capacitor of high capacity.

  In a preferred embodiment, this device comprises means for separating the rotor and the driven shaft, these means being controlled by means of opening the clutch which is mounted in the transmission between the drive shaft and the drive shaft. led tree.

  The invention will be better understood and other characteristics, details and advantages thereof will appear more clearly on reading the description which follows, given by way of example with reference to the appended drawings, in which: FIG. a schematic view in axial section of a transmission comprising a device according to the invention.

  - Figure 2 schematically shows a load circuit of a capacitor by the drummer of the device according to the invention.

  In FIG. 1, the reference numeral 10 designates a motor shaft, such as the crankshaft of a motor vehicle internal combustion engine, and the reference 12 a driven shaft, such as for example the input shaft of a motor vehicle. speeds.

  An inertia flywheel 14 is fixed at the end of the drive shaft 10 by screws 16 and forms the reaction plate of a clutch 18 of a conventional type, comprising a friction disc 20 which is connected in rotation to the driven shaft 12 via a torsion damper 22 of a conventional type, comprising elastically deformable vibration absorption means and torque irregularities transmitted by the drive shaft 10 and friction means for the vibration damping and absorbed torque irregularities.

  The clutch further comprises a pressure plate 24 which is integral in rotation with the flywheel 14 and which is axially displaceable in translation relative to the latter, and clutch and disengagement means formed by an annular diaphragm 26 which is mounted to tilt or pivoting on a clutch cover 28 integral with the flywheel 14.

  The radially outer portion of the annular diaphragm 26 urges the pressure plate 24 towards the flywheel 14 for clamping the friction linings carried by the clutch disk 20, and the radially inner portion of this annular diaphragm cooperates with a stop declutching 30 which surrounds the driven shaft 12 and which is axially displaceable in translation between a rest position shown in the drawings in which the clutch is closed or coupled, and a service position or disengagement position, in which the stop 30 is moved to the motor shaft 10 and the pressure plate 24 is spaced from the flywheel 14 for opening the clutch. The control means of the clutch abutment have not been shown and may be of a conventional type.

  In the example shown in FIG. 1, this clutch release bearing is mounted at the rear end (or end located on the opposite side to the drive shaft 10) of a cylindrical sleeve 32 which is mounted free to rotate and translate on the driven shaft 12 and whose rear end comprises means for securing in rotation with the driven shaft 12, these means comprising for example a dog clutch 34 or friction means 36 which are arranged between an outer shoulder of the shaft 12 (or a ring integral in rotation with the driven shaft 12) and a rear annular flange of the sleeve 32. The bushing 32 is mounted on the shaft 12 by means of a bearing bearing 38 for rotation and comprises its end before a stop not shown cooperating with the radially inner portion of the annular diaphragm 26.

  This bushing is connected by spring means 40 to a rotor 42 which extends radially along the annular diaphragm 26 and the clutch cover 28 and which carries permanent magnets 44 arranged facing stator fixed angular sectors 46 having electroconductive windings which are at short axial distance from the permanent magnets 44 carried by the rotor 42.

  The set of angular sectors 46 forms an electric machine stator whose windings are connected to a power supply 48 driven by a computer 50, which can be part of the engine control computer of the vehicle.

  Angular position sensors 52, 54 and 56 are here associated with the flywheel 14 integral with the drive shaft 10, the driven shaft 12 and the rotor 42 to detect their instantaneous angular positions.

  These sensors 52, 54 and 56 are of a known type, for example at 64 or 32 points per revolution.

  The assembly formed by the rotor 42, the stator 46 and the spring means 40 form an active beater whose power supply is controlled to generate an electromagnetic torque which is applied to the rotor and which is added to the return torque applied by the springs 40, this electromagnetic torque being either in phase with the return torque, or in phase opposition with it, to respectively increase or decrease the stiffness of the drummer and thus increase or decrease its own frequency.

  In operation, the vibrations and irregularities of torque transmitted by the drive shaft 10 and applied to the flywheel 14 and the driven shaft 12 are detected by analyzing the instantaneous angular positions of the flywheel 14, the shaft 12 and the rotor 42 provided by the sensors 52, 54, 56 to the computer 50.

  The electromagnetic torque applied to the rotor 42 is determined by the intensity of the supply current of the windings 46 and can be calculated directly from the instantaneous angular acceleration of the flywheel 14, obtained by a double derivative of the output signal of the sensor 52, and / or the instantaneous angular acceleration of the rotor 42, obtained by a double derivative of the output signal of the sensor 56.

  It has indeed been found that, as a function of the rotational speeds of the motor shaft 10 and the conditions of movement of the vehicle, the electromagnetic torque to be applied to the rotor 42 could be determined by the product of the inertia of the rotor 42. a constant and the angular acceleration of the flywheel 14 or the rotor 42 of the drummer.

  It is also possible, in some cases, to use for this calculation a delayed acceleration of the rotor 42. For example, when the sensor 56 for detecting the angular position of the rotor 42 is a 64-point sensor, an acceleration can be used. delayed angular 8 points which corresponds to an offset of 90 at the frequency of the harmonic 2 and therefore the shift between speed and acceleration at this frequency.

  It is advantageous to store in memory predetermined tables of values, which will be combined with the measured or calculated values of the acceleration of the flywheel 14 or that of the rotor 42, to determine the instantaneous electromagnetic torque to be applied. to the rotor 42 and therefore the intensity of the supply current of the windings 46 of the mixer.

  The signals provided by the sensor 54 associated with the driven shaft 12 make it possible to check the effectiveness of the control of the electric supply of the mixer.

  In the embodiment of the device according to the invention shown in FIG. 1, the rotational connection of the mixer and the motor shaft is disengageable, this disengagement occurring simultaneously with the opening of the clutch 18, when the sleeve 32 carrying the mixer is moved in axial translation to the drive shaft 10 by the control means of the clutch 18 to act on the radially inner portion of the annular diaphragm 26 and tilt on the clutch cover 18.

  This displacement of the beater towards the motor shaft 10 is translated by the clutching means 34 or the resting of the friction means 36 so that the rotor 42 and the sleeve 32 are no longer then connected to the driven shaft 12.

  This disengagement of the drummer has the advantage that, during the transmission gearbox changes in the gearbox shaft 12 is an input shaft, the inertia of the drummer is not added to that of the shaft 12 , which allows normal operation of synchronization means and interconnection.

  During most of the operation of the engine of the vehicle, the mixer is rotatably connected to the driven shaft 12 and is controlled by the computer 50 to operate as an electric generator during operation in gear engaged and the energy it produces is stored and returned during the transmission ratio changes to assist synchronization means and interconnection.

  The assembly shown diagrammatically in FIG. 2 can be used for this purpose, in which the windings 60 of the stator 46 are connected to a capacitor 62 of high capacity and to a bridge arrangement of power transistors 64 which are controlled by the computer 50. function of an acceleration signal 66 of the motor shaft 10 and of an acceleration signal 68 of the rotor 42. The energy stored in the capacitor 62, which is for example between 500 and 1000 Joules, is used during transmission ratio changes to increase or decrease the rotational speed of the driven shaft 12. 25

Claims (13)

  1. A method of filtering vibrations in a transmission, in particular for a motor vehicle, connecting a drive shaft (10) to a driven shaft (12) by means of a flywheel secured to the drive shaft and a torsion damper comprising a drummer formed of a rotor (42) rotatably mounted about the driven shaft (12), a stator (46), electromagnetic means (44, 60) mounted on the rotor, and the stator and connected to a power supply (48), and means (40) elastically deformable connecting the rotor (42) to the driven shaft (12), characterized in that it consists in controlling the power supply ( 48) electromagnetic means of the drummer from the instantaneous acceleration of the flywheel (14) and / or the rotor (42) and the inertia of the rotor (42) to apply to the rotor an electromagnetic torque, which adds to the restoring moment exerted on the rotor by its elastically deformable means (40) for connection to the arbr e conducted and which is substantially in phase or in phase opposition with this restoring torque, to change the natural frequency of the drummer and adapt it to the frequency of vibrations transmitted by the torsion damper to the driven shaft.   2. Method according to claim 1, characterized in that it consists in determining the electromagnetic torque applied to the rotor (42) from the product of the inertia and the instantaneous acceleration of the rotor (42).   3. Method according to claim 1, characterized in that it consists in determining the electromagnetic torque applied to the rotor (42) from the product of the inertia of the rotor and the instantaneous acceleration of the flywheel (14) .   4. Method according to claim 1, characterized in that it consists in determining the electromagnetic torque applied to the rotor (42) from a delayed angular acceleration of this rotor.   5. Method according to claim 4, characterized in that the acceleration of the rotor (42) is delayed by 90 at the frequency of the harmonic 2.   6. Method according to one of the preceding claims, characterized in that it consists in determining the control of the aforementioned power supply (48) from measurements of the instantaneous angular position of the rotor (42) and / or the steering wheel. inertia (14) and pre-stored value tables in memory.   7. Method according to one of the preceding claims, characterized in that it consists in using the mixer to filter the vibrations outside the transmission ratio changes and to charge a capacitor (62), the energy stored in the capacitor being restored for the synchronization of rotational speeds during gear changes.   8. Method according to one of claims 1 to 7, characterized in that it consists in separating the drummer from the driven shaft (12) during the gear ratio changes.   9. A device for filtering vibrations in a transmission between a motor shaft and a driven shaft, in particular for a motor vehicle, the transmission comprising a flywheel secured to the drive shaft and connected to the shaft driven by a shock absorber. twist, and a drummer comprising a rotor (42) rotatably mounted about the driven shaft (12), a stator, electromagnetic means (44, 60) mounted on the rotor and the stator and connected to a power supply ( 48) and elastically deformable means (40) for connecting the rotor (42) to the driven shaft (12), characterized in that it also comprises: - means (50, 52, 54, 56) for determining the the instantaneous acceleration of the flywheel (14) and / or the rotor (42), and means (50) for controlling the power supply (48) of the aforementioned electromagnetic means of the beater, these control means comprising calculation means for determining from the inertia of the rotor and the instantaneous acceleration of the flywheel or the rotor, the instantaneous value of the intensity of the feed current of the aforementioned electromagnetic means for applying to the rotor an electromagnetic torque, which is added to the return torque exerted on the rotor by its elastically deformable means (40) for connection to the driven shaft and which is in phase or in phase opposition with this restoring torque, in order to modify the natural frequency of the rotor and to adapt it to the frequency of the transmitted vibrations by the torsion damper to the driven shaft.   10. Device according to claim 9, characterized in that it comprises means (56) for measuring the instantaneous angular position of the rotor (42).   11. Device according to claim 9 or 10, characterized in that it also comprises means (52) for measuring the instantaneous angular position of the flywheel (14).   12. Device according to one of claims 9 to 11, characterized in that the electromagnetic means of the drummer comprises conductive windings (60) connected to a load circuit of a capacitor (62) under control of the control means (50). ).   13. Device according to one of claims 9 to 12, characterized in that it comprises means for detaching in rotation the rotor (42) and the driven shaft (12), these means being controlled by means of opening a clutch (18) mounted in the transmission between the motor shaft and the driven shaft (12).