Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D48/00—External control of clutches
  • F16D48/06—Control by electric or electronic means, e.g. of fluid pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D2500/00—External control of clutches by electric or electronic means
  • F16D2500/10—System to be controlled
  • F16D2500/102—Actuator
  • F16D2500/1021—Electrical type
  • F16D2500/1023—Electric motor
  • F16D2500/1024—Electric motor combined with hydraulic actuation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D2500/00—External control of clutches by electric or electronic means
  • F16D2500/30—Signal inputs
  • F16D2500/306—Signal inputs from the engine
  • F16D2500/3067—Speed of the engine
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D2500/00—External control of clutches by electric or electronic means
  • F16D2500/30—Signal inputs
  • F16D2500/306—Signal inputs from the engine
  • F16D2500/3067—Speed of the engine
  • F16D2500/3068—Speed change of rate of the engine
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D2500/00—External control of clutches by electric or electronic means
  • F16D2500/50—Problem to be solved by the control system
  • F16D2500/501—Relating the actuator
  • F16D2500/5014—Filling the actuator cylinder with fluid

Definitions

• the invention relates to a method and a device according to the preambles of claims 1 and 10.
• a method for adapting a rapid filling time of a slave cylinder of a clutch of a drive train is known.
• a contact point of the clutch is determined using pressure values.
• Generic drive units for example with an electric motor, which drives a drive wheel of a motor vehicle with the interposition of a switchable transmission such as a tarpaulin transmission, are known, for example, from publications DD 278307 A and EP 2597336 B1.
• components of the planetary gear such as ring gear and/or carrier are fixed to the housing by means of a brake band, so that different translations can be switched from the different torque paths with and without a rotating ring gear or carrier.
• the loading actuation of the brake band can be done in different ways by means of electric or hydraulic actuators, for example by means of hydrostatically actuated friction clutches.
• Such planetary gears are controlled by means of a control unit, which controls the corresponding actuators.
• the object of the invention is the further development of a method for controlling a hydraulic unit for actuating a friction clutch and the further development of a drive unit, in particular a wheel drive of a motor vehicle.
• a drive unit in particular a wheel drive of a motor vehicle.
• the proposed method is used to control a hydraulic unit for Actuate supply a friction clutch, for example, for a drive unit of a Radan drive on two or all drive wheels of a motor vehicle.
• a central and/or several decentralized control units are provided, which control the drive unit and a gear each of an output such as a wheel drive.
• the drive unit is preferably driven by an electric motor.
• the electric motor can be provided in a driving or recuperative manner.
• An at least two-speed planetary gear is connected downstream of the electric motor or its rotor.
• the planetary gear is designed at least in one stage, preferably in two stages.
• At least one sun gear, one ring gear and at least one web with rotatable and distributed over the circumference arranged planetary gears are provided as components of the planetary gear.
• the planet gears are each meshed with a sun gear and the associated ring gear.
• one component of the planetary gear for example a sun gear of a first stage, serves as the drive and is firmly connected to the rotor.
• two webs of different stages can be connected to the output, so that without reversing the direction of rotation, both a ring gear and a web can be connected to the housing, preferably overlapping and in opposite directions, in order to set two different transmission ratios between input and output.
• Two of each Components for switching the planetary gear can be fixed to the housing of the planetary gear, that is, can be connected to the housing.
• a ring gear can be connected to the housing by means of a first friction clutch and a carrier of the single-stage or multi-stage planetary gear can be connected to the housing by means of a second friction clutch.
• the friction clutches are designed, for example, as forcibly closed friction clutches, that is, the friction clutches are closed under hydrostatic pressure and are thus connected to the housing.
• the ring gear or web are each arranged such that they can rotate with respect to the housing.
• the friction clutches are alternately closed and open.
• the friction clutches are actuated in an overlapping manner, ie one friction clutch is opened and the other friction clutch is closed.
• the hydrostatic actuation of the friction clutches takes place by means of a hydraulic unit controlled by a control unit.
• the hydraulic unit contains a pressure supply device, for example an electrically operated pump. Both Hy draulic units of the two friction clutches can be fed from a common pressure supply device.
• the hydraulic unit contains a slave cylinder which actuates the friction clutch and is connected to the pressure supply device by means of a pressure line. Under pressure, the slave cylinder of the slave cylinder is shifted axially against the action of a spring element, for example a return spring, resulting in frictional engagement of a disk pack in the friction clutch between the housing and the relevant one Component of the planetary gear arranged lamellae and counter-lamellae is made forth.
• a spring element for example a return spring
• a pressure relief valve controlled by the control unit for example electromagnetically actuated, is connected in the pressure line between the pressure supply device and the slave cylinder.
• the pressure relief valve connects the slave cylinder to the pressure supply device in a first switching position. In a second switching position, the slave cylinder is connected to an unpressurized sump.
• the pressure relief valve is preferably actively switched from the second switching position to the first switching position against a return spring.
• the contact point of the friction clutch or the contact points of two friction clutches of a drive unit are continuously adapted by assigning them to a currently determined filling time of a filling time of the slave cylinder, so that a contact point of the associated friction clutch is identified based on the associated filling time.
• the filling time is with a given Path of a slave cylinder piston of the slave cylinder and thus correlated geometrically with the touch point.
• Corresponding conversions are stored in the control unit that controls the electric motor and can be determined empirically and stored, for example, as a map, table or formula.
• the contact point and the filling time point of the slave cylinder correlated therewith are determined based on a change in a rotational characteristic value of a rotor of the electric motor that drives the pump.
• the effect is used that when torque begins to be transmitted via the friction clutch, the friction clutch is engaged further by means of the slave cylinder, which continues to fill, and thus a displacement of the slave cylinder piston, in addition to the prestressing of the return spring, a prestressing of the disk pack of the friction clutch and thus the rotational parameters change due to the changed load, for example decrease.
• further sensor devices such as a pressure sensor in the pressure line with corresponding detection and evaluation software, can be dispensed with, so that the hydraulic unit can be manufactured more cost-effectively.
• the rotational parameters of the rotor can be recorded and processed without an additional sensor device for detecting the rotational parameters, in that the electric motor commutates electronically and speed information of the commutation is used for determination of the rotational characteristic value that is continuously recorded and evaluated for the adaptation of the contact point.
• the electric motor can be speed-controlled during operating times outside of the determination of the touch point, this being voltage-controlled at least during a determination of the touch point, for example in an open loop.
• the rotational characteristic is temperature-compensated. This means, for example, that viscosities, line cross-sections and the like that change due to temperature changes are compensated for.
• a temperature sensor can be provided for this purpose, which is directly in thermal connection with the pressure line or is arranged remotely from the pressure line, for example on a circuit board of the control unit, with the temperature of the hydraulic fluid being back-calculated using a temperature model.
• the rotational characteristic value used as a change in acceleration can be evaluated as a function of the speed of the electric motor, for example in order to compensate for inertia of the rotor, the pump and the like.
• the rotational characteristic value can be evaluated as a function of switching at least one valve of the hydraulic unit, for example the pressure relief valve, so that pressure drops at the valve that is not fully open, for example, can be compensated for.
• the currently determined rotational characteristic values are assigned to a FIFO data register with a fixed number of storage burst.
• the rotational parameters are gradually read in serially and further shifted, with the sum of the rotational parameters of the register being determined at each time cycle.
• the totals are each compared with a specified total value of the contact point and, given a specified total value, the key rotary value for the contact point or the associated filling time or the slave cylinder piston position is determined.
• the rotational characteristic values located at the memory locations can each be loaded with a coefficient that is specifically predetermined for the memory location.
• a rotational characteristic value located in the register at a centrally arranged storage location can have the smallest coefficient in terms of amount, for example zero, and the rotational characteristic values located in storage locations spaced apart from this in both temporal directions can be loaded with increasing coefficients in terms of amount.
• the treatment of the detected rotational parameters is used to filter the
• FIG. 1 shows a diagrammatically illustrated hydraulic unit for actuating a friction clutch
• FIG. 2 shows a diagram of the pressure of the pump in FIG. 1 or the acceleration of the electric motor over time
• FIG. 3 is a representation of an FIR filter of the rotational characteristic of the electric motor during a determination of the touch point of the friction clutch of FIG. 1 and
• FIG. 4 a simulation of a determination of the touch point of the friction clutch of FIG.
• FIG. 1 shows schematically the hydraulic unit 100 for one of the two friction clutches of a drive unit with two friction clutches that switch the transmission ratio of a planetary gear in the overlapping mode.
• a hydraulic unit 100 is provided for each of the friction clutches.
• the hydraulic unit 100 contains the pump 101 driven by a rotor of the electronically commutated electric motor M, which generates the pump pressure P p .
• the pressure relief valve 102 is arranged in the pressure line 103 between the pump 101 and the slave cylinder 104 and switches between the slave cylinder 104 on the one hand and on the other hand optionally between the pump 101 and the unpressurized sump 105, so that the slave cylinder 104 with the Gori f can be applied to the clutch pressure P c falling pump pressure P p with the flow Q or pressure relieved.
• the slave cylinder piston 106 is displaced under the clutch pressure P c against the action of the spring element 107 and, after the filling time At required to fill the slave cylinder 104, tensions the disk pack 108 at the contact point TP with greater rigidity than the spring element 107 of those not shown in detail friction clutch.
• the clutch pressure P c in the pressure line 103 slowly but surely decreases steadily to.
• the clutch pressure P c in the pressure line 103 increases with a greater gradient, since the disk set 108 is also prestressed.
• the friction clutch begins to transmit torque at contact point TP by means of the incipient frictional contact between the disks and counter-disks of disk set 108, so that the transition between the clutch pressure P c with a small gradient and the clutch pressure P c with a large gradient takes the filling time of slave cylinder 104 im It is essentially finished and a signal, for example a flag for the touch point TP, can be stored in the software for controlling the friction clutch.
• the reaction of the load of the electric motor M driving the pump 101 is evaluated in order to determine the touch point TP at the transition between a small and a large increase in the clutch pressure P c without an additional pressure sensor.
• rotational parameters for example changes in the acceleration of the rotor of the electric motor M, are evaluated via the filling time At during an actuation process of the friction clutch using the sensor device for commutation of the electric motor. wherein the electric motor M is operated at least during the filling time At in an open loop, for example with a fixed voltage being specified.
• the transition between the smaller and the larger slope of the clutch pressure P c can be detected based on the change in acceleration of the rotor over the filling time At and the touch point can be defined at the transition.
• the detected rotational characteristic of the change in acceleration may be subjected to FIR filtering.
• the friction clutch is preferably designed according to the normally open principle. This means that the friction clutch is opened when there is no pressure in the pressure line 103 and is closed under the applied clutch pressure P c . This in turn means that the component of the planetary gear associated with this friction clutch is connected to the housing under pressure.
• Figure 2 shows schematically the relationship between clutch pressure P c and acceleration A over time t with reference to hydraulic unit 100 in Figure 1.
• pressure relief valve 102 is closed, pump pressure P p is released into pressure line 103 and drops at the Gorif orifice to the clutch pressure P c .
• the slave cylinder 104 is filled with pressure medium over the time t and the slave cylinder piston 106 is displaced within the filling time At against the action of the spring element 107 until the disks and counter disks of the disk pack 108 come into contact in the detected time interval At c .
• FIG. 3 shows schematically the use of an FIR filter 300 on the detected acceleration values of the rotor of the electric motor M for determining the contact point TP.
• the contact point TP is determined in the direction of the increasing displacement of the slave cylinder piston 106 via the filling time D ⁇ and a part of the preload of the disk set via the time interval D ⁇ 0 of Figure 2 by register 301 with here five memory locations 302, 303, 304, 305, 306 filled according to the FIFO principle (first-in-first-out) with acceleration values c4, c3, c2, c1, cO recorded in successive interrupts and according to the principle of the FIR filter 300 with a finite impulse response (FIR; finite impulse response filter) is evaluated.
• the touch point TP or the filling time value assigned to it is recognized if the value resulting from the FIR filter 300 corresponds to a calibrated variable.
• the FIR filter 300 for determining the touch point TP of FIG. 2, for example, is shown in principle.
• the sum of the acceleration values c4, c3, c2, c1, c0 of the memory locations 302, 303, 304, 305, 306 is formed for each interrupt according to the specified formula. If this sum corresponds to a calibrated value, the filling time value associated with the acceleration value c2 is adopted as the touch point TP.
• Figure 4 shows the determination of the contact point TP at the filling time t(TP) as a simulation 400 of the hydraulic unit 100 to operate a friction clutch.
• curve 401 partial diagram I shows the acceleration values A(x) determined from filter 300 for each interrupt over time t.
• the acceleration values A(x) are recorded via the filling time At and the time interval At c and is then aborted because, after the maximum torque that can be transmitted via the friction clutch has been reached, the speed n of the pump 101 is reduced or switched off with a corresponding preload of the disk pack and there are no reproducible acceleration values A(x).
• the contact point TP is assigned to the filling time t(TP) as soon as the acceleration values A(x) fall below a limit value, for example the acceleration value A(TP) or the change in acceleration DA exceeds a predetermined limit value.
• Partial diagram II shows curves 402, 403, 404, 405 over time t.
• the curve 402 shows the speed n of the rotor of the electric motor M, the curve 403 the pump pressure P p of the pump 101, the curve 404 the clutch pressure P c and the curve 405 the acceleration A of the rotor of the electric motor M over time t.
• the values of curve 405 serve as a basis for filtering using the FIR filter 300 as shown in curve 401 .
• the other curves 402, 403, 404 are only shown for information purposes and are not explicitly necessary for determining the touch point TP.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)
• Control Of Transmission Device (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=76958673

Family Applications (1)

Country Status (3)

Citations (7)

• 2021
  • 2021-07-06 CN CN202180060137.4A patent/CN116134234A/zh active Pending
  • 2021-07-06 WO PCT/DE2021/100584 patent/WO2022017560A1/de active Application Filing
  • 2021-07-06 DE DE102021117343.4A patent/DE102021117343A1/de active Pending

Patent Citations (7)

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