EP1224104A1 - Control unit for a wheel brake of a motor vehicle - Google Patents

Control unit for a wheel brake of a motor vehicle

Info

Publication number
EP1224104A1
EP1224104A1 EP00967578A EP00967578A EP1224104A1 EP 1224104 A1 EP1224104 A1 EP 1224104A1 EP 00967578 A EP00967578 A EP 00967578A EP 00967578 A EP00967578 A EP 00967578A EP 1224104 A1 EP1224104 A1 EP 1224104A1
Authority
EP
European Patent Office
Prior art keywords
pump
cylinder
brake
pressure
piston
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00967578A
Other languages
German (de)
French (fr)
Inventor
Guenter Wolff
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1224104A1 publication Critical patent/EP1224104A1/en
Withdrawn legal-status Critical Current

Links

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
    • B60T8/36—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 including a pilot valve responding to an electromagnetic force
    • B60T8/3615—Electromagnetic valves specially adapted for anti-lock brake and traction control systems
    • B60T8/3655—Continuously controlled electromagnetic valves
    • 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
    • B60T13/66—Electrical control in fluid-pressure brake systems
    • B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
    • B60T13/686—Electrical control in fluid-pressure brake systems by electrically-controlled valves in hydraulic systems or parts thereof
    • 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
    • B60T13/745—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 a hydraulic system, e.g. a 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
    • 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
    • B60T8/321—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 deceleration
    • B60T8/3255—Systems in which the braking action is dependent on brake pedal data
    • B60T8/326—Hydraulic systems
    • 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
    • B60T8/404—Control of the pump unit
    • B60T8/4059—Control of the pump unit involving the rate of delivery
    • 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
    • B60T8/42—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 having expanding chambers for controlling pressure, i.e. closed systems
    • 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
    • B60T8/48—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 connecting the brake actuator to an alternative or additional source of fluid pressure, e.g. traction control systems
    • B60T8/4809—Traction control, stability control, using both the wheel brakes and other automatic braking systems
    • B60T8/4827—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems
    • B60T8/4863—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems
    • 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
    • F16D65/00—Parts or details
    • F16D65/14—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position
    • F16D65/16—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake
    • F16D65/18—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake adapted for drawing members together, e.g. for disc brakes
    • 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
    • F16D65/00—Parts or details
    • F16D65/38—Slack adjusters
    • F16D2065/386—Slack adjusters driven electrically
    • 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
    • F16D2121/00—Type of actuator operation force
    • F16D2121/02—Fluid pressure

Definitions

  • the invention relates to an actuating unit according to the preamble of patent claim 1.
  • Such an actuation unit for a wheel brake of a motor vehicle is already known (DE 195 27 936 AI), in which an electric motor which can be varied in speed drives a gear pump which releases pressure medium from a
  • the known actuation unit is disadvantageous in that there is always a pressure medium-conducting connection to the reservoir when the brake is actuated.
  • the actuation unit is therefore not a closed hydraulic system, which represents a considerable lack of safety.
  • the reservoir must be of a relatively large size in order to provide a sufficient volume of pressure medium when the brake lining is badly worn.
  • the actuation unit according to the invention with the features of claim 1 has the advantage that its functional reliability is increased because a closed hydraulic system is present.
  • the same pressure medium volumes are always exchanged between the cylinder chamber of the cylinder-piston unit and the cylinder chamber on the side facing away from the brake lining.
  • the changed piston position is compensated in this way even if the brake lining wears. If the hydraulic system is completely sealed, there is no need to add pressure medium. This simplifies the maintenance of the actuation unit, which is four times available in a car, for example.
  • the actuating unit can also be mounted on the vehicle filled with pressure medium.
  • An embodiment of the invention is shown in simplified form in the drawing as a circuit diagram of an actuation unit for a wheel brake of a motor vehicle and is explained in more detail in the following description.
  • a motor vehicle not shown in the drawing, is equipped on its wheels with an actuating unit 1 for a wheel brake 2.
  • the actuating unit 1 shown as a circuit diagram has a cylinder-piston unit 3, the cylinder 4 of which is penetrated in its entire length by a piston rod 5.
  • a piston 6 arranged on this is formed with the same surfaces on both sides.
  • the piston 6 separates two cylinder spaces 7 and 8 filled with a hydraulic pressure medium from one another in the cylinder 4.
  • the piston rod 5 of the cylinder-piston unit 3 acts on at least one brake pad 9, which can be pressed against and lifted off from a friction element 10 connected to a vehicle wheel, in the case of a disk brake a brake disk.
  • the actuating unit 1 includes a hydraulic pump 14 which can be driven by an electric motor 13 to vary its speed. This is on its suction side 15 by a suction line 16 with the cylinder chamber 7 on the brake lining side and on its pressure side 17 by a
  • a return line 19 is provided, which connects the pressure line 18 to the suction line 16 and in which a 2/2-way valve 20 is arranged, which assumes its open position in a spring-actuated manner and can be controlled electromagnetically in its blocking position and in any intermediate positions.
  • the suction side 15 of the pump 14 is connected to a small-volume pressure medium expansion tank 21 which is sealed from the atmosphere by an air and moisture-tight membrane 22.
  • a measuring transducer 23, hereinafter referred to as a pressure sensor is connected to the pressure line 18 to measure the pressure in the cylinder chamber 8 facing away from the brake lining.
  • the actuation unit 1 and the actuation units assigned to the other vehicle wheels can be controlled by the vehicle driver by means of a brake pedal 26, the pedal travel of which can be detected by a transducer 27, hereinafter referred to as a travel sensor.
  • a transducer 27 hereinafter referred to as a travel sensor.
  • an electronic control unit 28 is provided, with which the signal representing an electrical braking request signal of the displacement sensor 27 can be processed. With the control unit 28, the electric motor 13 and the directional control valve 20 are all
  • Actuating units 1 of the vehicle controllable Furthermore, the signals measured by the pressure sensors 23 of the actuation units 1 can be processed in the control unit 28.
  • the control unit 28 contains slip-dependent signals, which are detected on the vehicle wheels with wheel sensors (not shown), for the purpose of slip control, e.g. Can be processed for a brake lock protection, traction control or driving stability control of the vehicle.
  • the actuation unit 1 has the following functionality:
  • the control unit 28 puts the electric motor 13 of the pump 14 into operation and the directional control valve 20 is switched into its blocking position.
  • the pump 14 draws in pressure medium from the cylinder chamber 7 on the brake lining side and conveys this into the cylinder chamber 8 of the cylinder-piston unit 3 facing away from the brake lining.
  • the piston 6 with piston rod 5 is shifted to the left in the drawing and the at least one brake lining 9 against the friction element 10 pressed depending on the pump pressure.
  • the variable-speed control of the electric motor 13 can Pressure rise rate can be set depending on the course of the brake request signal.
  • the pressure acting in the cylinder space 8 is detected by the pressure sensor 23 and its signal processed in the control unit 28.
  • the directional control valve 20 is controlled into an intermediate position so that the pressure medium conveyed by the pump 14 is discharged through the return line 13 to the suction side 15 of the pump while maintaining the brake pressure.
  • the intermediate position of the directional control valve 20 is changed or this is switched to its open position. Due to the elasticity of the wheel brake 2, the piston 6 is reset and the pressure medium derived from the cylinder chamber 8 facing away from the brake lining is returned to the cylinder chamber 7 on the brake lining side.
  • the gradient for pressure build-up and pressure reduction in the cylinder chamber 8 can be controlled. Furthermore, it is possible with the actuating unit 1 to control the brake pressure for the purpose of slip control when starting and braking, for driving stability control and for driver-independent braking.
  • the pressure medium expansion tank 21 is not required per se, since the hydraulic system described is a is closed and when braking only pressure medium between the two cylinder spaces 7 and 8 is exchanged.
  • the expansion tank 21 can be used to replace lost pressure medium at sealing points of the cylinder-piston unit 3 or the pump 14 or to compensate for heat-related volume fluctuations in the pressure medium in the system.
  • the actuation unit 1 is a system that is self-sufficient for each vehicle wheel. Each is advantageous
  • Actuating unit of the vehicle to a separate energy supply or groups of actuating units are connected to separate energy supplies. In the event of a power supply failure, the remaining actuation units remain functional.

Abstract

The invention relates to a control unit (1) for a wheel brake (2) of a motor vehicle. The control unit is provided with a hydraulic pump (14) which can be driven in a speed-variable manner by means of an electromotor (13). The inventive unit also comprises an element (20) that adjusts a reflux of pressure means to the pump and is arranged between the pressure side (17) and the suction side (15) of the pump (14). Furthermore, a cylinder-piston unit (3) having a piston (6) with surfaces that are the same on both sides and a cylinder (4) with cylinder chambers (7, 8) that are arranged on both sides of the piston is provided. The aim of the invention is to press a brake lining (9) against a friction element (10) which is connected to the wheel of the vehicle. The suction side of the pump (14) is connected to the cylinder chamber (7) situated on the side of the brake lining and the pressure side of the pump is connected to the cylinder chamber (8) facing away from the brake lining. A control device (28) is allocated to the control unit (1). An electric brake request signal can be processed and the electromotor (13) and the element (20) can be controlled by means of said control device.

Description

Betätigungseinheit für eine Radbremse eines KraftfahrzeugsActuating unit for a wheel brake of a motor vehicle
Stand der TechnikState of the art
Die Erfindung geht aus von einer Betätigungseinheit nach der Gattung des Patentanspruchs 1.The invention relates to an actuating unit according to the preamble of patent claim 1.
Es ist schon eine solche Betätigungseinheit für eine Radbremse eines Kraftfahrzeugs bekannt (DE 195 27 936 AI) , bei der ein drehzahlveränderlich steuerbarer Elektromotor eine Zahnradpumpe antreibt, welche Druckmittel aus einemSuch an actuation unit for a wheel brake of a motor vehicle is already known (DE 195 27 936 AI), in which an electric motor which can be varied in speed drives a gear pump which releases pressure medium from a
Vorratsbehälter ansaugt und in eine Zylinder-Kolben-Einheit fördert, mit deren Kolben ein Bremsbelag gegen ein mit einem Fahrzeugrad verbundenes Reibelement preßbar ist. Druckseitig der Pumpe ist eine Drossel vorgesehen, mit der eine Verbindung zum Vorratsbehälter steuerbar ist. Durch entsprechende Steuerung von Pumpenantrieb und Drossel mittels einer elektronischen Bremsregelung sollen Druckaufbau, Druckhalten und Druckabbau in der Zylinder- Kolben-Einheit verwirklicht werden.Sucks in the reservoir and conveys it into a cylinder-piston unit, with the piston of which a brake lining can be pressed against a friction element connected to a vehicle wheel. A throttle is provided on the pressure side of the pump, with which a connection to the reservoir can be controlled. By appropriate control of the pump drive and throttle by means of an electronic brake control, pressure build-up, pressure maintenance and pressure reduction are to be realized in the cylinder-piston unit.
Die bekannte Betätigungseinheit ist insofern nachteilig, da bei einer Bremsbetätigung stets eine druckmittelleitende Verbindung zum Vorratsbehälter besteht. Damit ist die Betätigungseinheit kein geschlossenes hydraulisches System, was einen erheblichen Sicherheitsmangel darstellt. Außerdem muß der Vorratsbehälter relativ groß bemessen sein, um bei stark verschlissenem Bremsbelag ein ausreichendes Druckmittelvolumen bereitzustellen.The known actuation unit is disadvantageous in that there is always a pressure medium-conducting connection to the reservoir when the brake is actuated. The actuation unit is therefore not a closed hydraulic system, which represents a considerable lack of safety. Moreover The reservoir must be of a relatively large size in order to provide a sufficient volume of pressure medium when the brake lining is badly worn.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Betätigungseinheit mit den Merkmalen des Patentanspruchs 1 hat demgegenüber den Vorteil, daß deren Funktionssicherheit erhöht ist, weil ein geschlossenes hydraulisches System vorliegt. Bei einem Bremsvorgang werden nämlich stets die gleichen Druckmittelvolumina zwischen dem bremsbelagseitigen und dem bremsbelagabgewandten Zylinderraum der Zylinder-Kolben-Einheit ausgetauscht. Auch bei Verschleiß des Bremsbelags wird die veränderte Kolbenstellung auf diese Weise ausgeglichen. Bei völliger Dichtheit des hydraulischen Systems ist ein Nachfüllen von Druckmittel überflüssig. Dies vereinfacht die Wartung der zum Beispiel bei einem Pkw vierfach vorhandenen Betätigungseinhei . Auch kann die Betätigungseinheit bereits mit Druckmittel gefüllt am Fahrzeug montiert werden.The actuation unit according to the invention with the features of claim 1 has the advantage that its functional reliability is increased because a closed hydraulic system is present. During a braking process, the same pressure medium volumes are always exchanged between the cylinder chamber of the cylinder-piston unit and the cylinder chamber on the side facing away from the brake lining. The changed piston position is compensated in this way even if the brake lining wears. If the hydraulic system is completely sealed, there is no need to add pressure medium. This simplifies the maintenance of the actuation unit, which is four times available in a car, for example. The actuating unit can also be mounted on the vehicle filled with pressure medium.
Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen und Verbesserungen der im Patentanspruch 1 angegebenen Betätigungseinheit möglich.The measures listed in the subclaims allow advantageous developments and improvements of the actuating unit specified in claim 1.
Zeichnungdrawing
Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung als Schaltplan einer Betätigungseinheit für eine Radbremse eines Kraftfahrzeugs vereinfacht dargestellt und in der nachfolgenden Beschreibung näher erläutert .An embodiment of the invention is shown in simplified form in the drawing as a circuit diagram of an actuation unit for a wheel brake of a motor vehicle and is explained in more detail in the following description.
Beschreibung des Ausführungsbeispiels Ein in der Zeichnung nicht dargestelltes Kraftfahrzeug ist an seinen Rädern jeweils mit einer Betätigungseinheit 1 für eine Radbremse 2 ausgestattet . Die als Schaltschema wiedergegebene Betätigungseinheit 1 weist eine Zylinder- Kolben-Einheit 3 auf, deren Zylinder 4 in seiner gesamten Länge von einer Kolbenstange 5 durchdrungen ist . Ein auf dieser angeordneter Kolben 6 ist mit beiderseits gleichen Flächen ausgebildet. Der Kolben 6 trennt im Zylinder 4 zwei mit einem hydraulischen Druckmittel gefüllte Zylinderräume 7 und 8 voneinander ab. Die Kolbenstange 5 der Zylinder- Kolben-Einheit 3 wirkt auf wenigstens einen Bremsbelag 9 ein, der gegen ein mit einem Fahrzeugrad verbundenes Reibelement 10, bei einer Scheibenbremse eine Bremsscheibe, preßbar und von diesem abhebbar ist .Description of the embodiment A motor vehicle, not shown in the drawing, is equipped on its wheels with an actuating unit 1 for a wheel brake 2. The actuating unit 1 shown as a circuit diagram has a cylinder-piston unit 3, the cylinder 4 of which is penetrated in its entire length by a piston rod 5. A piston 6 arranged on this is formed with the same surfaces on both sides. The piston 6 separates two cylinder spaces 7 and 8 filled with a hydraulic pressure medium from one another in the cylinder 4. The piston rod 5 of the cylinder-piston unit 3 acts on at least one brake pad 9, which can be pressed against and lifted off from a friction element 10 connected to a vehicle wheel, in the case of a disk brake a brake disk.
Zu der Betätigungseinheit 1 gehört eine durch einen Elektromotor 13 drehzahlveränderlich antreibbare hydraulische Pumpe 14. Diese steht auf ihrer Saugseite 15 durch eine Saugleitung 16 mit dem bremsbelagseitigen Zylinderraum 7 und auf ihrer Druckseite 17 durch eineThe actuating unit 1 includes a hydraulic pump 14 which can be driven by an electric motor 13 to vary its speed. This is on its suction side 15 by a suction line 16 with the cylinder chamber 7 on the brake lining side and on its pressure side 17 by a
Druckleitung 18 mit dem bremsbelagabgewandten Zylinderraum 8 der Zylinder-Kolben-Einheit 3 in druckmittelleitender Verbindung. Außerdem ist eine Rückführleitung 19 vorgesehen, welche die Druckleitung 18 mit der Saugleitung 16 verbindet und in der ein 2/2-Wegeventil 20 angeordnet ist, welches federbetätigt seine Durchlaßstellung einnimmt und elektromagnetbetätigt in seine Sperrstellung sowie in beliebige Zwischenstellungen steuerbar ist. Ferner steht die Saugseite 15 der Pumpe 14 mit einem kleinvolumigen Druckmittel-Ausgleichsbehälter 21 in Verbindung, der durch eine luft- und feuchtigkeitsdichte Membrane 22 gegen Atmosphäre abgedichtet ist. Schließlich ist an die Druckleitung 18 ein der Messung des Druckes im bremsbelagabgewandten Zylinderraum 8 dienender Meßumformer 23, nachfolgend als Drucksensor bezeichnet, angeschlossen. Die Betätigungseinheit 1 sowie den weiteren Fahrzeugrädern zugeordnete Betätigungseinheiten sind vom Fahrzeugführer mittels eines Bremspedals 26 ansteuerbar, dessen Pedalweg mit einem Meßumformer 27, nachfolgend als Wegsensor bezeichnet, erfaßbar ist. Darüber hinaus ist ein elektronisches Steuergerät 28 vorgesehen, mit dem das ein elektrisches Bremsanforderungssignal des Wegsensors 27 darstellende Signal verarbeitbar ist. Mit dem Steuergerät 28 sind der Elektromotor 13 und das Wegeventil 20 allerPressure line 18 with the cylinder chamber 8 facing away from the brake lining of the cylinder-piston unit 3 in a fluid-conducting connection. In addition, a return line 19 is provided, which connects the pressure line 18 to the suction line 16 and in which a 2/2-way valve 20 is arranged, which assumes its open position in a spring-actuated manner and can be controlled electromagnetically in its blocking position and in any intermediate positions. Furthermore, the suction side 15 of the pump 14 is connected to a small-volume pressure medium expansion tank 21 which is sealed from the atmosphere by an air and moisture-tight membrane 22. Finally, a measuring transducer 23, hereinafter referred to as a pressure sensor, is connected to the pressure line 18 to measure the pressure in the cylinder chamber 8 facing away from the brake lining. The actuation unit 1 and the actuation units assigned to the other vehicle wheels can be controlled by the vehicle driver by means of a brake pedal 26, the pedal travel of which can be detected by a transducer 27, hereinafter referred to as a travel sensor. In addition, an electronic control unit 28 is provided, with which the signal representing an electrical braking request signal of the displacement sensor 27 can be processed. With the control unit 28, the electric motor 13 and the directional control valve 20 are all
Betätigungseinheiten 1 des Fahrzeugs steuerbar. Desweiteren sind die von den Drucksensoren 23 der Betätigungseinheiten 1 gemessenen Signale im Steuergerät 28 verarbeitbar. Schließlich sind in dem Steuergerät 28 schlupfabhängige Signale, welche mit nicht dargestellten Raddrehfühlern an den Fahrzeugrädern erfaßt werden, zum Zwecke der Schlupfregelung z.B. für eine Bremsblockierschutz-, Antriebsschlupfschütz- oder Fahrstabilitätssteuerung des Fahrzeugs verarbeitbar.Actuating units 1 of the vehicle controllable. Furthermore, the signals measured by the pressure sensors 23 of the actuation units 1 can be processed in the control unit 28. Finally, the control unit 28 contains slip-dependent signals, which are detected on the vehicle wheels with wheel sensors (not shown), for the purpose of slip control, e.g. Can be processed for a brake lock protection, traction control or driving stability control of the vehicle.
Die Betätigungseinheit 1 hat folgende Funktionsweise:The actuation unit 1 has the following functionality:
Mit der Erzeugung eines Bremsanforderungssignals, sei es durch Bremspedalbetätigung oder die nicht näher beschriebene Radschlupfsteuerung des Fahrzeugs, werden vom Steuergerät 28 der Elektromotor 13 der Pumpe 14 in Betrieb gesetzt und das Wegeventil 20 in seine Sperrstellung geschaltet. Die Pumpe 14 saugt aus dem bremsbelagseitigen Zylinderraum 7 Druckmittel an und fördert dieses in den bremsbelagabgewandten Zylinderraum 8 der Zylinder-Kolben- Einheit 3. Der Kolben 6 mit Kolbenstange 5 wird in der Zeichnung nach links verschoben und der wenigstens eine Bremsbelag 9 gegen das Reibelement 10 in Abhängigkeit vom Pumpendruck gepreßt. Dabei kann mittels der drehzahlveränderlichen Steuerung des Elektromotors 13 die Druckeinstiegsgeschwindigkeit in Abhängigkeit vom Verlauf des Bremsanforderungssignal eingestellt werden. Der im Zylinderraum 8 wirkende Druck wird vom Drucksensor 23 erfaßt und dessen Signal im Steuergerät 28 verarbeitet. Mit Erreichen des vom Bremsanforderungssignal abhängigen Drucks im Zylinderraum 8 wird das Wegeventil 20 in eine Zwischenstellung gesteuert, so daß unter Aufrechterhaltung des Bremsdruckes das von der Pumpe 14 geförderte Druckmittel durch die Rückführleitung 13 zur Saugseite 15 der Pumpe abgeleitet wird. Zur Verringerung und gegebenenfalls dem völligen Abbau des Drucks im Zylinderraum 8 wird die Zwischenstellung des Wegeventils 20 verändert oder dieses in seine Durchlaßstellung geschaltet. Aufgrund der Elastizität der Radbremse 2 wird der Kolben 6 zurückgestellt und das aus dem bremsbelagabgewandten Zylinderraum 8 abgeleitete Druckmittel in den bremsbelagseitigen Zylinderraum 7 zurückgeführt .When a brake request signal is generated, whether by actuating the brake pedal or the wheel slip control of the vehicle, which is not described in more detail, the control unit 28 puts the electric motor 13 of the pump 14 into operation and the directional control valve 20 is switched into its blocking position. The pump 14 draws in pressure medium from the cylinder chamber 7 on the brake lining side and conveys this into the cylinder chamber 8 of the cylinder-piston unit 3 facing away from the brake lining. The piston 6 with piston rod 5 is shifted to the left in the drawing and the at least one brake lining 9 against the friction element 10 pressed depending on the pump pressure. Here, the variable-speed control of the electric motor 13 can Pressure rise rate can be set depending on the course of the brake request signal. The pressure acting in the cylinder space 8 is detected by the pressure sensor 23 and its signal processed in the control unit 28. When the pressure in the cylinder chamber 8 which is dependent on the brake request signal is reached, the directional control valve 20 is controlled into an intermediate position so that the pressure medium conveyed by the pump 14 is discharged through the return line 13 to the suction side 15 of the pump while maintaining the brake pressure. To reduce and, if necessary, completely reduce the pressure in the cylinder space 8, the intermediate position of the directional control valve 20 is changed or this is switched to its open position. Due to the elasticity of the wheel brake 2, the piston 6 is reset and the pressure medium derived from the cylinder chamber 8 facing away from the brake lining is returned to the cylinder chamber 7 on the brake lining side.
Während der gesamten Dauer der Bremsung ist der Elektromotor 13 eingeschaltet und die Pumpe 14 fördert ständigDuring the entire duration of the braking, the electric motor 13 is switched on and the pump 14 continuously pumps
Druckmittel. Je nach Druckmittelbedarf im bremsbelagabgewandten Zylinderraum 8 der Zylinder-Kolben- Einheit 3 wird der durch die Rückführleitung 19 fließende Druckmittel-Rückstrom zur Pumpe mittels des Wegeventils 20 eingestellt. Dabei kann mit dem Wegeventil 20 imPressure medium. Depending on the pressure medium requirement in the cylinder chamber 8 facing away from the brake lining of the cylinder-piston unit 3, the pressure medium backflow flowing through the return line 19 to the pump is set by means of the directional control valve 20. It can with the directional control valve 20 in
Zusammenwirken mit der Pumpe 14 der Gradient für Druckaufbau und Druckabbau im Zylinderraum 8 gesteuert werden. Desweiteren ist es mit der Betätigungseinheit 1 möglich, den Bremsdruck zum Zwecke der Schlupfsteuerung beim Anfahren und Bremsen, zur Fahrstabilitätssteuerung sowie zum fahrerunabhängigen Bremsen zu steuern.In cooperation with the pump 14, the gradient for pressure build-up and pressure reduction in the cylinder chamber 8 can be controlled. Furthermore, it is possible with the actuating unit 1 to control the brake pressure for the purpose of slip control when starting and braking, for driving stability control and for driver-independent braking.
Für den Betrieb der Betätigungseinheit 1 ist der Druckmittel-Ausgleichsbehälter 21 an und für sich nicht erforderlich, da das beschriebene hydraulische System ein geschlossenes ist und bei einer Bremsung lediglich Druckmittel zwischen den beiden Zylinderräumen 7 und 8 ausgetauscht wird. In der Praxis kann der Ausgleichsbehälter 21 benutzt werden, um an Dichtstellen der Zylinder-Kolben- Einheit 3 oder der Pumpe 14 verlorengegangenes Druckmittel zu ersetzen oder wärmebedingte Volumenschwankungen des im System befindlichen Druckmittels auszugleichen.For the operation of the actuating unit 1, the pressure medium expansion tank 21 is not required per se, since the hydraulic system described is a is closed and when braking only pressure medium between the two cylinder spaces 7 and 8 is exchanged. In practice, the expansion tank 21 can be used to replace lost pressure medium at sealing points of the cylinder-piston unit 3 or the pump 14 or to compensate for heat-related volume fluctuations in the pressure medium in the system.
Die Betätigungseinheit 1 ist ein für jedes Fahrzeugrad autarkes Systems. Vorteilhafterweise ist jedeThe actuation unit 1 is a system that is self-sufficient for each vehicle wheel. Each is advantageous
Betätigungseinheit des Fahrzeugs an eine separate Energieversorgung oder sind Gruppen von Betätigungseinheiten an separate Energieversorgungen angeschlossen. Beim Ausfall einer Energieversorgung bleiben die übrigen Betätigungseinheiten funktionsfähig. Actuating unit of the vehicle to a separate energy supply or groups of actuating units are connected to separate energy supplies. In the event of a power supply failure, the remaining actuation units remain functional.

Claims

Ansprüche Expectations
1. Betätigungseinheit (1) für eine Radbremse (2) eines Kraftfahrzeugs ,1. actuating unit (1) for a wheel brake (2) of a motor vehicle,
- mit einer durch einen Elektromotor (13) drehzahlveränderlich antreibbaren hydraulischen Pumpe (14) ,- With a hydraulic pump (14) which can be driven by an electric motor (13) at variable speeds,
- mit einem zwischen der Druckseite (17) und der Saugseite (15) der Pumpe (14) angeordneten Element (20) zur Einstellung eines Druckmittel-Rückstroms,- With an element (20) arranged between the pressure side (17) and the suction side (15) of the pump (14) for setting a pressure medium backflow,
- mit einer druckseitig an die Pumpe (14) angeschlossenen Zylinder-Kolben-Einheit (3), mit der wenigstens ein- With a cylinder-piston unit (3) connected on the pressure side to the pump (14), with which at least one
Bremsbelag (9) gegen ein mit einem Fahrzeugrad verbundenes Reibelement (10) preßbar und von diesem abhebbar ist,Brake pad (9) can be pressed against a friction element (10) connected to a vehicle wheel and can be lifted off the latter,
- sowie mit einem Steuergerät (28) , mit dem ein elektrisches Bremsanforderungssignal verarbeitbar sowie der Elektromotor (13) und das Element (20) steuerbar sind, dadurch gekennzeichnet, daß die Zylinder-Kolben-Einheit (3) einen Kolben (6) mit beiderseits gleichen Flächen und einen Zylinder (4) mit beiderseits des Kolben (6) angeordneten Zylinderräumen (7, 8) aufweist, und daß die Saugseite (15) der Pumpe (14) mit dem bremsbelagseitigen Zylinderraum verbunden ist.- And with a control unit (28) with which an electrical brake request signal can be processed and the electric motor (13) and the element (20) can be controlled, characterized in that the cylinder-piston unit (3) has a piston (6) on both sides same surfaces and a cylinder (4) with cylinder spaces (7, 8) arranged on both sides of the piston (6), and that the suction side (15) of the pump (14) is connected to the cylinder lining on the brake lining side.
2. Betätigungseinheit nach Anspruch 1, dadurch gekennzeichnet, daß bei einer Bremsbetätigung die Pumpe (14) ständig angetrieben und das den Druckmittel-Rückstrom zu der Pumpe (14) einstellende Element ein 2/2-Wegeventil (20) mit einer beliebigen Anzahl Zwischenstellungen ist.2. Actuating unit according to claim 1, characterized in that when the brake is actuated, the pump (14) constantly driven and the element setting the pressure medium return flow to the pump (14) is a 2/2-way valve (20) with any number of intermediate positions.
3. Betätigungseinheit nach Anspruch 2, dadurch gekennzeichnet, daß druckseitig der Pumpe (14) ein Meßumformer (23) für Druck angeschlossen ist, dessen Signal im Steuergerät (28) verarbeitbar ist.3. Actuating unit according to claim 2, characterized in that a pressure transmitter (23) is connected to the pressure side of the pump (14), the signal of which can be processed in the control unit (28).
4. Betätigungseinheit nach Anspruch 1, dadurch gekennzeichnet, daß die Saugseite (15) der Pumpe (14) mit einem Druckmittel-Ausgleichsbehälter (21) verbunden ist. 4. Actuating unit according to claim 1, characterized in that the suction side (15) of the pump (14) is connected to a pressure medium expansion tank (21).
EP00967578A 1999-10-15 2000-09-14 Control unit for a wheel brake of a motor vehicle Withdrawn EP1224104A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19949815 1999-10-15
DE19949815A DE19949815A1 (en) 1999-10-15 1999-10-15 Operating unit for wheel brake of car has piston-cylinder unit having piston with uniform surfaces on both sides plus cylinder with cylinder chambers on both sides of piston
PCT/DE2000/003199 WO2001028832A1 (en) 1999-10-15 2000-09-14 Control unit for a wheel brake of a motor vehicle

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EP1224104A1 true EP1224104A1 (en) 2002-07-24

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EP (1) EP1224104A1 (en)
JP (1) JP2003516261A (en)
DE (1) DE19949815A1 (en)
WO (1) WO2001028832A1 (en)

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WO2018224236A1 (en) * 2017-06-07 2018-12-13 Robert Bosch Gmbh Vehicle brake system and method of assembling

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US6988047B1 (en) 2006-01-17

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