Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
  • B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
  • B60T13/741—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive acting on an ultimate actuator
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
  • B60T8/17—Using electrical or electronic regulation means to control braking
  • B60T8/172—Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
  • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
  • B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
  • B60T13/14—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using accumulators or reservoirs fed by pumps
  • B60T13/142—Systems with master cylinder
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
  • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
  • B60T13/58—Combined or convertible systems
  • B60T13/588—Combined or convertible systems both fluid and mechanical assistance or drive
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
  • B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
  • B60T13/746—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive and mechanical transmission of the braking action
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T7/00—Brake-action initiating means
  • B60T7/02—Brake-action initiating means for personal initiation
  • B60T7/08—Brake-action initiating means for personal initiation hand actuated
  • B60T7/085—Brake-action initiating means for personal initiation hand actuated by electrical means, e.g. travel, force sensors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
  • B60T8/17—Using electrical or electronic regulation means to control braking
  • B60T8/171—Detecting parameters used in the regulation; Measuring values used in the regulation
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P3/00—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters
  • H02P3/02—Details of stopping control
  • H02P3/04—Means for stopping or slowing by a separate brake, e.g. friction brake or eddy-current brake

Definitions

• the invention relates to a clamping force adjustment device for an electromechanical brake.
• Many vehicles include electromechanical brakes for at least some of their wheels. Such brakes can be used as parking brakes, but also as service brakes during movement of the vehicle and as emergency brakes in special circumstances. When they are used as a service brake, the braking that they impose depends on the pressure on the brake pedal by the driver and the hydraulic pressure that he then applies.
• an engine control unit automatically applies brake application strategies, predefined according to various parameters of the state or driving of the vehicle, by imposing application movements to a brake actuator, by starting an electric motor.
• An object of the invention is therefore to avoid excessive application of electromechanical brakes by blindly applying a strategy independent of a hydraulic pressure already present in the brake.
• Another object of the invention is to estimate and to put in relation of calculation the two components of hydraulic and mechanical force which take part together in the application of the brake, although they depend on physical phenomena and on heterogeneous mechanisms, and are obtained from measurements and calibrations which may be imprecise, in order to obtain despite this the result, mentioned above, of an almost invariable final tightening force, with satisfactory precision.
• Yet another object of the invention is to ensure the maintenance of a sufficient clamping force, even in circumstances where the hydraulic pressure will not be maintained, due to a relaxation of the support of the brake pedal. by the driver.
• the invention relates to a motor control unit intended to control an electric actuator motor of an electromechanical vehicle brake, comprising:
• a decision module designed to control the command supply module according to predefined strategies, the strategies comprising, for the tightening commands, stopping the tightening at a target tightening force applied by the brake, the stopping being decided by the decision module according to the measurements of the values of the electric current according to the measurement of the hydraulic pressure.
• the mechanical component of the mechanical clamping force applied by the brake is correlated to the value of the current necessary for the electric motor moving the brake actuator, and the clamping is stopped when the sum of the mechanical component and the hydraulic tightening component, estimated thanks to the pressure measurement, reaches a target value defined by the strategy.
• the invention relates to an electromechanical brake device for a vehicle, comprising said brake, which is associated with a wheel of the vehicle, an actuator of the brake, said electric motor of the actuator, and the preceding electric motor motor control unit.
• the decision module is designed to estimate a total clamping force applied to the brake by adding a first component depending on the values of the electric current and a second component depending on an estimate of the hydraulic pressure;
• the hydraulic pressure measurement is made at a master cylinder of the vehicle
• the estimate of the estimated hydraulic pressure is equal to the measurement of the hydraulic pressure reduced by a fixed value
• the second component is proportional to the estimate of the hydraulic pressure, by applying a reduction coefficient to said estimate of the hydraulic pressure;
• the decision module is designed to estimate the second component, then estimate a value of the first force component for which the tightening force will be equal to the target tightening force, and stop the command providing module when a threshold of the electric current, estimated as corresponding to said value of the first force component, is measured.
• Another object of the invention is a vehicle provided with an electromechanical brake device according to the above.
• FIG. 1 schematically shows a motor vehicle
• FIG. 2 illustrates a brake comprising an exploded parking device
• FIG. 8 is a diagram of a hydraulic brake circuit.
• FIG. 1 represents an automobile 1 equipped with two driving and steering front wheels 2 on a front axle 3, and two non-driving and non-steering rear wheels 4 on a rear axle 5.
• Each of the front wheels 2 is here equipped with a service brake 6 actuated directly by the driver by pressing a brake pedal
• each of the rear wheels 4 is equipped with a brake 7 described below in detail, and which is associated with an actuator 8 able to make it work in parking and emergency brake.
• the actuators 8 of the two brakes 7 are controlled by the same engine control unit 9 according to various information relating to certain parameters of the vehicle 1 and its driving state.
• the engine control unit 9 is active when emergency braking becomes necessary or parking is requested.
• the brakes 7 are also actuated by the driver at the same time as the brakes 6 at the front.
• FIG. 2 schematically illustrates a known and non-limiting embodiment of the brake 7, according to an exploded view.
• the brake 7 comprises a caliper 11 joined to a casing 12 of cylindrical shape. It also includes a gearmotor 60, one flange 61 of which is joined to a flange 62 on the rear face of the casing 12 by screws (not shown here).
• the geared motor 60 contains an electric motor 18 and gears for reducing the rotational speed of said electric motor 18.
• the housing 12 comprises a hydraulic cavity 13 called a cylinder, open towards the front (on the right in FIG. 2) and in which slides a piston 14 carrying a movable pad (not shown).
• Braking is carried out by causing the piston 14 to slide forwards, to bring the movable pad closer to a fixed pad located at the front end of the caliper 11 and grip a disc of the rear wheel 4 between these pads.
• This movement of the piston 14 is obtained, when the brake 7 works as a service brake, by the application of hydraulic pressure in the hydraulic cavity 13 while driving the vehicle: this pressure is exerted on the rear face of the piston 41 and pushes him forward.
• brake 7 is controlled as a parking brake or an emergency brake
• the braking is carried out by the use of the electric motor 18 according to strategies imposed by the motor control unit 9.
• the electric motor 18 sets in motion the gears of the geared motor 60, which causes a screw 15 which extends in the hydraulic cavity 13.
• the screw 15 engages with a nut 16 on which a rear face of the piston 14 is then in abutment.
• the rotations of the screw 15 are converted into translations of the nut 16 and of the piston 14, which moves according to the duration of actuation of the electric motor 18.
• the actuator 8 considered here comprises in particular the geared motor 60 and therefore its electric motor 18, and the system 17 made up of screw 15 and nut 16.
• the invention could be applied to other vehicles and other brakes than these.
• Figure 3 illustrates the motor control unit 9 in more detail: it comprises: a command supply module 19 which supplies commands to the electric motor 18 according to the predefined strategies, being connected to a battery or another source of energy present in the vehicle 1; a current measurement module 20 which measures the intensity of the current in the electric circuit on which the electric motor 18 and said energy source are installed; a pressure measurement module 21 which measures hydraulic pressure in the braking system; and a decision module 23 which connects the command supply modules 19 and measurement modules 20 and 21, and which uses the output signal of the measurement modules 20 and 21 to adjust the duration of the commands.
• a command supply module 19 which supplies commands to the electric motor 18 according to the predefined strategies, being connected to a battery or another source of energy present in the vehicle 1
• a current measurement module 20 which measures the intensity of the current in the electric circuit on which the electric motor 18 and said energy source are installed
• a pressure measurement module 21 which measures hydraulic pressure in the braking system
• a decision module 23 which connects the command supply modules 19 and measurement modules 20 and 21, and which uses the output
• FIG. 4 It illustrates a diagram 30 of the electric current I applied to the electric motor 18, and a diagram 31 corresponding to the clamping force F of the brake 7 during the known strategy, as a function of time t, and in the absence of hydraulic pressure in the brake 7.
• the current diagram 30 comprises three successive portions: a starting peak 32, a flat portion 33, and an increasing portion 34.
• the starting peak portion 32 begins from the instant ti of application of the strategy, has a short duration and a high value; it corresponds to the starting of the motor and does not produce tightening.
• the flat portion 33 corresponds to an empty stroke of the piston 14 before the tightening actually begins and is carried out at a nearly constant and low value of the current I from a time t?.
• the increasing portion 34 begins at a time ts and has a roughly uniform slope with time. It corresponds to a gradual increase in the clamping force F, or its mechanical component.
• the force diagram 31 comprises a portion of zero (or negligible) force 35, then a portion of increasing force 36 starting at a time t4 simultaneous or almost simultaneous with time t3.
• the growth of the clamping force F has an almost invariable slope in this growth part 36, so that the clamping force can, at least approximately, be correlated to the value of the current I by a proportionality relationship .
• the tightening strategy is stopped when an intensity threshold li of the current I, correlated to a target force F Tar of the tightening, is reached.
• the clamping force F varies very little thereafter.
• the current diagram, now 40 still has a starting peak portion 42, a flat portion 43 and a growing portion 44, similar to the previous ones, except that the durations of the flat portion 43 and of the growing portion 44 may be different.
• the increasing portion 44 is interrupted at the intensity threshold 11, identical to the previous one, of the current I.
• a first step is a decision (E50) to apply the tightening strategy, and the motor is started (E51).
• the measurements of the electric current (E57) are taken immediately after tightening has been decided, and they are compared (E58) with the final value determined in step E56.
• the strategy is continued as long as the values of the repetitive current measurements remain below the modified threshold I2, and interrupted when the current measurement values reach this threshold.
• the motor is then stopped (E59).
• FIG. 7 shows that the current diagram 40 is replaced by a current diagram 63 which differs in that the increasing portion, now 64, is shorter by stopping at the modified threshold I2, lower than li, calculated in step E55.
• the corresponding force diagram 65 likewise comprises an increasing portion, now 66, shorter and which stops near the target force Fyar (unchanged with respect to the known strategy), since the mechanical component of the clamping force , for wheel parking braking, has been reduced by a value corresponding as far as possible to the existing hydraulic component.
• This hydraulic component FHyd is maintained for a flat portion 67, corresponding to the flat portion 45, of the force diagram 61.
• FIG. 8 represents a hydraulic braking circuit, comprising a master cylinder 70, a pressure amplifier, a pump or any other source of pressurized brake fluid, in communication by a network 71 of pipes with the cylinders 13a to 13d of the brakes 6 and 7, electromechanical or not, fitted to the wheels 2 and 4 of the vehicle 1. It is preferred that the existing hydraulic pressure be measured at the master cylinder 70 rather than at the cylinders 13a to 13d, because it can be estimated with greater precision. big.
• a correction of the measured value P me s is applied to take into account the uncertainties of the measurements. It can be, for conventional braking systems where the hydraulic pressure can reach approximately 150 bars (15 MPa), from 7 to 15 bars (0.7 to 1.5 MPa), and for example 10 bars (1 MPa).
• the measured value Pmes is reduced by this value, in order to not to overestimate the hydraulic component of the tightening force and to guarantee sufficient final tightening.
• This correction value is denoted P CO rr.
• a reduction coefficient K CO rr of between 15 and 30% (between 0.15 and 0.30 in the formula below), and for example around 20%, can be applied.
• F ⁇ arNew F ⁇ ar Fhyd
• the value of the modified threshold l 2 at which the strategy is stopped can be obtained by a formula such as:
• I? I l . ( F ⁇ arNew / F ⁇ ar ), possibly adjusted according to the characteristics, obtained empirically, of the behavior of the brake 7 and the actuator 8.
• the invention can be implemented in different ways: the correction or reassessment calculations of the hydraulic pressure applied and of the mechanical component of force to be applied could thus be done according to an order different from that of steps E53 to E56.
• the hydraulic pressure measurement can be made with an already existing sensor on the vehicle 1, and may or may not be renewed during the application of the strategy.
• P is Estimated Pressure t1 to t5 Instants of time diagrams t Time

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• Engineering & Computer Science (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Power Engineering (AREA)
• Braking Systems And Boosters (AREA)
• Regulating Braking Force (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=82196563

Family Applications (1)

Country Status (5)

Family Cites Families (7)

• 2021
  • 2021-12-21 FR FR2114147A patent/FR3130724B1/fr active Active
• 2022
  • 2022-12-20 EP EP22850656.4A patent/EP4433342A1/de active Pending
  • 2022-12-20 CN CN202280084134.9A patent/CN118434606A/zh active Pending
  • 2022-12-20 US US18/717,004 patent/US20250042370A1/en active Pending
  • 2022-12-20 WO PCT/FR2022/052449 patent/WO2023118738A1/fr not_active Ceased

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