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
  • 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
  • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
  • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
  • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
  • B60T8/4072—Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking
  • B60T8/4081—Systems with stroke simulating devices for driver input
• • 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
  • B60T7/04—Brake-action initiating means for personal initiation foot actuated
  • B60T7/042—Brake-action initiating means for personal initiation foot actuated by electrical means, e.g. using travel or 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
  • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
  • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
  • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
  • B60T8/4072—Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking

Definitions

• the invention relates to an electrohydraulic brake system for motor vehicles, which can be controlled in a “brake-by-wire” operating mode both by the vehicle driver and independently of the vehicle driver, with a master brake cylinder that can be actuated by means of a brake pedal and has at least one pressure chamber, a pressureless pressure medium reservoir, and one an electronic control and regulating unit which can be controlled hydraulic pressure source, the pressure of which can be applied to the vehicle's wheel brakes, which are connected to the master brake cylinder by means of at least one connection which can be shut off by a separating valve and which pressure control valves (intake valve, exhaust valve) are assigned which are controlled by the electronic control and control unit can be controlled analog and the wheel brakes either with the pressure source or
• the device for adjusting the flexibility of the brake pedal has a first pedal travel valve and a second pedal travel valve, one of the pedal travel valves between the master brake cylinder and the suction side of one of the Pressure source associated pump or a low pressure accumulator and the other of the pedal travel valves between the master brake cylinder and the pressure side of the pump or a high pressure accumulator assigned to the pressure source is arranged.
• the electronic control unit is set up to control the two pedal travel valves as a function of an actuation of the brake pedal, the pedal travel valves being designed as proportional travel or pressure valves.
• the electrically controllable valve arrangement is formed by the isolating valve, a pressure regulating or control valve connected to the output side of the isolating valve, the output connection of which is connected to the pressure medium reservoir, and further valves which act on the pressure chamber of the master brake cylinder enable the pressure set in at least one wheel brake and / or the pressure applied by the pressure source.
• the isolating valve is designed as an analog, controllable, normally open (SO) 2/2-way valve, while the Pressure control valve is designed as an analog controllable, normally closed (SG) 2/2-way valve.
• the control valve connected to the outlet side of the isolating valve can be designed as a normally closed (SG) switching valve.
• valves which allow the pressure in the pressure chamber (4) of the master brake cylinder to be acted upon by the pressure which is controlled in at least one wheel brake are formed by the outlet valves connected to the outlet side of the first separating valve and assigned to the individual wheel brakes ,
• valves that allow the pressure chamber of the master brake cylinder to be acted upon by the pressure applied by the pressure source are formed by the inlet valves assigned to the individual wheel brakes and the outlet valves.
• an analog controllable pressure control valve is connected between the pressure source and the pressure chamber of the master brake cylinder.
• inlet valves assigned to the wheel brakes are designed as normally closed (SG) 2/2-way valves.
• the outlet valves assigned to the wheel brakes are designed as normally open (SO) 2/2-way valves.
• the master brake cylinder is designed as a tandem master cylinder
• the outlet connections of the outlet valves, which are assigned to the second brake circuit, and the outlet connection of the second one Isolating valve can be connected to the pressure medium reservoir via an electrically controllable switching valve.
• a pressure control valve with an overpressure function is connected between the output connection of the pressure source and the first isolating valve, which, when the first isolating valve is open, enables the pressure chamber of the master brake cylinder to be acted upon in a controlled manner with the pressure applied by the pressure source.
• a further advantageous embodiment of the subject matter of the invention provides that an analogly controllable pressure control valve is connected in the connection between the pressure source and the inlet side of the inlet valves.
• hydraulic-mechanical means are provided between the master brake cylinder and the isolating valve, which allow a preselected flexibility of the brake pedal in the “brake-by-wire” operating mode.
• Fig. 2 shows the structure of a second embodiment of the brake system according to the invention in the inactive or de-energized state
• Fig. 3 shows the structure of a third embodiment of the brake system according to the invention in a representation corresponding to FIGS. 1 and 2.
• the brake system of the “brake-by-wire ⁇ ” type which is shown only schematically in the drawing, has an actuation unit 2 which can be actuated by means of an actuation pedal provided with the reference numeral 1 and which essentially consists of a dual-circuit pressure transmitter or master brake cylinder 3 and an unpressurized pressure medium reservoir 6.
• the master brake cylinder 3 in turn has two separate pressure spaces 4, 5, which are connected to the pressure medium reservoir 6.
• a wheel brake 7 assigned to the right front wheel of the motor vehicle and a wheel brake 8 assigned to the left rear wheel of the motor vehicle are connected to the first pressure chamber (primary pressure chamber) 4, to which a pressure sensor 13 is connected, by means of a lockable first hydraulic line 11.
• the line 11 is shut off by means of a first isolating valve 9, which is preferably designed as an electromagnetically actuated, normally open (SO), analog controllable 2/2-way valve.
• the output side of the first isolating valve 9 is connected by means of a hydraulic connecting line 16 to the pressure medium reservoir 6, in which an electromagnetically actuated, normally closed (SG-), analog controllable 2/2-way valve 17 is inserted.
• the first isolating valve 9 and the 2/2-way valve 17, which can be regulated in an analog manner, form an electrically controllable device which, in the “brake-by-wire” operating mode, enables a preselected flexibility of the brake pedal 1 and thus gives the driver the familiar brake pedal feeling.
• the second pressure chamber 5 of the master brake cylinder 2 can be connected to the other pair of wheel brakes 14, 15 via a second hydraulic line 12 which can be shut off by means of a second separating valve 10 and which is assigned to the right rear wheel of the motor vehicle and one to the left front wheel of the motor vehicle.
• the second isolating valve 10 is designed as an electromagnetically actuated, normally open (SO) switching valve, the output side of which can be connected to the pressure medium reservoir 6 with the interposition of an electromagnetically actuated, normally open (SO) switching valve 18. Otherwise, the construction of the hydraulic circuit connected to the second pressure chamber 5 of the master brake cylinder 2 corresponds identically to that of the brake circuit 11 explained in the above description, so that it does not need to be discussed in the following text.
• a motor-pump unit 20 serving as an external pressure source is provided with a high-pressure accumulator 21, which in turn consists of a pump 23 driven by an electric motor 22.
• the suction side of the pump 23 is connected via a check valve 34 to the input side of the pressure control valve 17 mentioned above or the output side of the first isolating valve 9.
• the outlet of the high-pressure accumulator 21 is connected via a pressure relief valve 24 to a line section 31 which connects the first isolating valve 9 to the 2/2-way valve 17 which can be regulated in an analog manner.
• the filling state of the high-pressure accumulator 21 is monitored by means of a displacement sensor 25, which is only indicated schematically.
• a third hydraulic line 26 connects the pressure side of the pump 23 or the output of the high-pressure accumulator 21 to the input side of two electromagnetically actuated, analog controllable, preferably normally closed (SG) 2/2-way or inlet valves 27, 28 are connected upstream of the wheel brakes 7 and 8 and serve to build up a hydraulic pressure in these wheel brakes.
• the reduction of the hydraulic pressure applied in the wheel brakes 7, 9 is served by two electromagnetically actuated, analog controllable, preferably normally open (SO) 2/2-way or exhaust valves 29, 30, the output connections of which are connected to the previously mentioned line section 31
• the wheel brake 7 is assigned a pressure sensor 32, with the aid of which the hydraulic pressure prevailing in the wheel brake 7 is determined.
• An electronic control and regulating unit ECU 34 which in particular serves to control the motor-pump assembly 20, the valves 9, 10, 17, 18, 27, 28, 29, 30 and the pressure control valves assigned to the second brake circuit 12 the output signals of the pressure sensors 13, 32, the displacement sensor 25 and a preferably redundant brake request detection device 33, which is assigned to the master brake cylinder 3, are supplied.
• an analog controllable 2/2-way valve 35 with overpressure function is connected between the outlet of the high-pressure accumulator 21 and the line section 31 mentioned in connection with FIG.
• an analog controllable 2/2-way valve 35 with overpressure function is connected between the outlet of the high-pressure accumulator 21 and the line section 31 mentioned in connection with FIG.
• similarly controllable, normally closed (SG) 2/2-way valve 36 is provided which, when a pressure equal to zero is set in line 26, enables a targeted application of a defined pressure medium volume to the wheel brakes 7, 8, -.
• the pressure values determined by the pressure sensors 32 can then be evaluated to detect gases in the system.
• both the isolation valves 9, 10 assigned to the pressure chambers 4, 5 of the master brake cylinder 2 are designed as analog-controllable, normally open (SO) 2/2-way valves.
• the outputs of the isolating valves 9, 10 are connected on the one hand to the outlet side of the outlet valves 29, 30, -, - and on the other hand to the pressure medium reservoir 6 via switching valves 37, - which are closed when de-energized.
• the output of the high-pressure accumulator 21 is connected to the first pressure chamber 4 of the master brake cylinder 2 via an analog controllable, normally closed (SG) 2/2-way valve 38.
• Brake request detection device 33 control signals which are supplied to the previously mentioned electronic control unit 34 which generates control signals which are used to switch over the separating, pressure regulating as well as described in the preceding text Shutter valves are used. These control signals activate the first isolating valve 9 in a controlled manner, the second isolating valve 10 is closed, and the pressure control valve 17 is opened.
• a pressure maintenance phase is initiated by switching the inlet valves 27, 28, -, - into their closed position.
• the inlet valves 27, 28, -, - are closed and the corresponding outlet valves 29, 30, -, - are opened in a controlled manner.
• the valves 17, 18 connected to the lines leading to the pressure medium reservoir 6 are also opened.
• the pressure medium volume consumed in the wheel brakes 7, 8 is first used to reset the master cylinder pistons.
• This volume of pressure medium flows through the now open outlet valves 29, 30 and the opened isolating valve 9 into the first pressure chamber 4 of the master brake cylinder 2. Since in some cases this volume is not sufficient to reset the master cylinder piston completely, the inlet valves 27, 28 are also opened , so that 21 pressure medium volume from the high pressure accumulator Can be "pushed". The use of the volume from the wheel brakes is energetically advantageous.
• the release process proceeds similarly in the embodiment according to FIG. 3.
• the switching valves 37, - mentioned above are closed, the pressure medium volume provided by the high-pressure accumulator 21 flowing in with closed inlet valves 27, 28 being regulated via the pressure control valve 38.
• the outlet valves 29, 30, - are opened.
• the brake system according to the invention automatically switches to a fallback operating mode in which driver braking is possible.
• Both the isolation valves 9, 10 and the exhaust valves 29, 30, -, - are switched to the inactive switch position shown in the drawing, so that a hydraulic connection between the master cylinder 3 and the wheel brakes is released, via which pressure can be built up ,

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Regulating Braking Force (AREA)
• Braking Systems And Boosters (AREA)

Applications Claiming Priority (7)

Publications (1)

Family

ID=27214631

Family Applications (1)

Country Status (4)

Families Citing this family (9)

Family Cites Families (5)

• 2002
  • 2002-10-04 WO PCT/EP2002/011171 patent/WO2003033323A1/de active Application Filing
  • 2002-10-04 EP EP02801314A patent/EP1439992A1/de not_active Withdrawn
  • 2002-10-04 US US10/492,123 patent/US20040262993A1/en not_active Abandoned
  • 2002-10-04 JP JP2003536080A patent/JP4247832B2/ja not_active Expired - Fee Related

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events