EP1658445A1 - Vehicle braking system - Google Patents
Vehicle braking systemInfo
- Publication number
- EP1658445A1 EP1658445A1 EP04738830A EP04738830A EP1658445A1 EP 1658445 A1 EP1658445 A1 EP 1658445A1 EP 04738830 A EP04738830 A EP 04738830A EP 04738830 A EP04738830 A EP 04738830A EP 1658445 A1 EP1658445 A1 EP 1658445A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- self
- wheel brakes
- brake
- travel
- wedge
- 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- Withdrawn
Links
Classifications
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- 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
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- 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
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- 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
- B60T2270/00—Further aspects of brake control systems not otherwise provided for
- B60T2270/83—Control features of electronic wedge brake [EWB]
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- 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
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- 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
- F16D2121/18—Electric or magnetic
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- 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
- F16D2127/00—Auxiliary mechanisms
- F16D2127/08—Self-amplifying or de-amplifying mechanisms
- F16D2127/10—Self-amplifying or de-amplifying mechanisms having wedging elements
Definitions
- the invention relates to a vehicle brake system with the features of the preamble of claim 1.
- the vehicle brake system is intended in particular for motor vehicles such as cars and trucks and motorcycles.
- Self-energizing electromechanical wheel brakes are known.
- DE 101 51 950 A1 discloses such a brake, which is designed as a disc brake.
- the known wheel brake has an electromechanical actuating device with an electric motor and a spindle drive as a rotation / translation conversion gear, with which the friction brake pad can be displaced and can thus be pressed against a brake disc.
- the friction brake lining lies in a brake caliper, which is designed in a manner known per se as a so-called floating caliper, ie it can be displaced transversely to the brake disc.
- a second friction brake lining which rests on an opposite side of the brake disc like the one friction brake lining in the brake caliper, is pressed in a manner known per se when the friction brake lining is pressed onto the brake disc by transverse displacement of the brake caliper to the other side of the brake disc pressed.
- Other designs of electromechanical actuators are also known.
- the known friction brake has a wedge mechanism with a wedge arranged on a rear side of the one friction brake lining applied to the brake disc, which is supported on an inclined surface in the brake caliper, which extends obliquely to the brake disc at an angle corresponding to a wedge angle.
- the electromechanical actuating device moves the friction brake lining in a direction of rotation of the brake disc, which rotates in the direction of an increasingly wedge gap between the inclined surface and the brake caliper.
- the friction brake pad moves obliquely at a wedge angle towards the brake disc and is pressed against it.
- a frictional force exerted by the rotating brake disk on the friction brake lining acts on the friction brake lining in the direction of the widening wedge gap between the inclined surface of the brake caliper and the brake disc.
- the inclined surface exerts a supporting force on the wedge which has a force component transverse to the brake disc.
- This force component transverse to the brake disc represents a pressure force which presses the friction brake lining against the brake disc in addition to a force applied by the actuating device and thereby increases the braking force.
- a lever mechanism can also be provided with a lever which supports the friction brake lining at an angle to the brake disc when braking.
- a support angle of the lever corresponds to a wedge angle of the wedge mechanism.
- hydraulic self-boosting devices are also known, for example.
- the invention is also not limited to disc brakes as wheel brakes, other brake designs can also be used.
- a self-amplification factor is constant in a wedge mechanism assuming a constant coefficient of friction.
- the ramp angle of which changes over its course the self-amplification can be changed as a function of a displacement path of the friction brake lining and thus as a function of an actuation, pressure and braking force.
- a large ramp angle at the beginning of the ramp enables rapid infeed at the start of actuation of the wheel brake, and a small self-reinforcement with high pressure and braking force is achieved by a small ramp angle at the end of the ramp.
- EP 953 785 A2 discloses a full-pad disc brake with a pad carrier ring, which is arranged coaxially with a brake disc on one side and carries the friction brake pads on its side facing the brake disc.
- the lining carrier ring On a side facing away from the brake disc, the lining carrier ring has wedge elements, which are supported on rotatably and stationary mounted rollers. By turning the lining carrier ring, the wedge elements come into contact with the rollers, as a result of which the lining carrier ring is moved in the direction of the brake disk and the friction brake linings are pressed against the brake disk.
- the wedge elements have mutually oblique wedge surfaces, so that when the brake disc rotates in the opposite direction, the brake disc carrier ring also in the opposite direction, i.e. is turned again in the direction of rotation of the brake disc.
- Self-energizing electromechanical wheel brakes used in practice always have a self-energizing device for one and another Self-boosting device for a reverse direction of rotation, for example, two oppositely inclined wedge elements, in order to have a self-boosting effect for forward and backward travel.
- the wedge angle and thus the self-amplification can be the same or different for forward and reverse travel.
- Self-boosting devices for both directions of rotation have the disadvantage that the wheel brake is more complex in its construction and therefore more expensive.
- Another disadvantage is that the friction brake lining for actuating the wheel brake must always be moved in the direction of rotation in order to achieve self-reinforcement.
- the vehicle brake system according to the invention with the features of claim 1 has self-energizing electromechanical wheel brakes assigned to vehicle wheels.
- the invention provides that all or at least some of the wheel brakes have self-amplification only for one direction of travel.
- the vehicle brake system can also be designed as a so-called hybrid brake system, in which only a part of the wheel brakes are actuated electromechanically and other wheel brakes are actuated hydraulically or in another way non-electromechanically.
- the invention has the advantage that by using electromechanical self-energizing wheel brakes only in one direction of rotation, at least for some of the wheel brakes, it is structurally simpler and therefore cheaper manufacturable wheel brakes are used. The vehicle brake system is therefore cheaper.
- Another advantage of the invention is that for wheel brakes with self-amplification, only in one direction of rotation, no rotation or direction of travel detection is required to actuate the brakes, since the friction brake lining is always shifted in the same direction for actuation.
- An additional advantage of the invention is a simple possibility of adjusting the wear. When the wheel brakes are released, the friction brake lining is reset so far that a desired clearance, ie a desired gap between the friction brake lining and the brake disc, is established.
- Claim 1 is directed to the fact that wheel brakes assigned to a front axle of a vehicle have self-amplification which is effective only in the forward direction of travel.
- the wheel brakes which in any case have to exert the highest braking force in passenger cars, have self-amplification only in the forward direction of travel.
- claim 2 provides that wheel brakes assigned to a rear axle have a self-boosting that is effective only in the reverse direction.
- claim 3 provides that the wheel brakes assigned to the rear axle as well as the wheel brakes assigned to the front axle have self-amplification which is effective only in the forward direction of travel.
- a high braking force in the forward direction of travel on both vehicle axles is important, since the greatest braking forces are required here.
- the braking force is sufficient for reversing.
- Claim 4 provides that wheel brakes assigned to a rear axle have effective self-boosting devices in both directions of travel.
- wheel brakes are used for the rear axle which, as is customary in practice, have self-amplification in both directions of travel.
- at least the wheel brakes of an axle have a self-boosting effect even when reversing.
- more complex and expensive wheel brakes have to be accepted.
- the embodiment according to claim 5 provides that wheel brakes assigned to a rear axle have no self-boosting device.
- the braking force of the wheel brakes on the rear axle is independent of the direction of travel of the vehicle.
- Such wheel brakes are structurally simpler because of the lack of a self-energizing device and are therefore less expensive.
- the independent claim 8 provides that electromechanical wheel brakes assigned to a front axle have self-amplification effective in both directions of travel and that wheel brakes assigned to a rear axle have self-amplification effective only in one direction of travel.
- this embodiment of the invention too, there is a self-reinforcing effect when reversing on a vehicle axle, in this case on the front axle.
- On the rear axle structurally simpler and less expensive wheel brakes are used. Possibly.
- the wheel brakes assigned to the rear axle can also be designed without a self-boosting device. drawing
- Figure 1 is a self-energizing electromechanical disc brake
- Figures 2 to 6 possible arrangements of self-energizing electromechanical wheel brakes on the front and rear axles of a motor vehicle according to the invention.
- the wheel brake according to the invention shown in FIG. 1 is designed as a disc brake 10. It has a floating caliper 12 which is displaceable transversely to a brake disk 14.
- the brake disc 14 is rotatably connected to a vehicle wheel 15.
- In the brake caliper 12 there are two friction brake linings 16, 18 on both sides of the brake disc 14, one of which has a friction brake lining 16 for braking with an electromechanical actuating device 20 which can be displaced in a circumferential or rotational direction of the brake disc 14 and whose other friction brake lining 18 is arranged immovably in the brake caliper 12.
- the actuating device 20 has an electric motor 22 with which the friction brake lining 16 can be displaced via a spindle drive 24.
- the friction brake pad 16 is supported by a wedge 26 on an inclined surface 28 of the brake caliper 12, it can be displaced along the inclined surface 28 with the actuating device 20.
- the friction brake pad 16 is displaced with the actuating device 20 along the inclined surface 28 in the direction of a wedge gap between the inclined surface 28 and the brake disk 14 that becomes narrower.
- the friction brake pad 16 thereby moves towards the brake disc 14 and is on pressed this.
- the brake caliper 12 is displaced transversely to the brake disc 14 in a manner known per se and presses the other friction brake lining 18 against the other side of the brake disc 14, which is thereby braked.
- the brake disc 14 acts on the two friction brake linings 16, 18 with a frictional force which is directed in the direction of rotation of the brake disc 14.
- the friction force exerted by the rotating brake disc 14 on the displaceable friction brake lining 16 pressed against it causes the support on the inclined surface 28 according to the so-called wedge principle a force with a component transverse to the brake disc 14.
- This force presses the friction brake pad 16 in addition to the actuating device 20 against the brake disc 14, the pressing force of both friction brake pads 16, 18 and thus the braking force is increased.
- This effect is called self-reinforcement.
- the disc brake 10 With the wedge 26, which is supported on the inclined surface 28 of the brake caliper 12, the disc brake 10 has a mechanical self-boosting device with a wedge mechanism.
- the wedge mechanism causes a self-weakening, ie a pressing force of the friction brake pads 16, 18 against the brake disc 14 and thus a braking force of the disc brake 10 is less than it would be without the wedge mechanism.
- FIGS. 2 to 6 show different possible arrangements of a self-energizing electromechanical wheel brake 10, as shown in FIG. 1, on wheels 30, 32, 34, 36 of a motor vehicle, not shown, in particular a passenger car.
- the wheel brakes of the passenger car do not necessarily have to have the construction shown schematically and simplified in FIG. 1, other brake designs are also known and possible.
- the vehicle brake system of the motor vehicle can also be designed as a hybrid brake system, ie it has, for example, two electromechanical wheel brakes 10, as shown in FIG. 1, on one vehicle axle and, for example, conventional hydraulic wheel brakes on the other vehicle axle.
- a The forward driving direction of the motor vehicle is assumed to the left in FIGS. 2 to 6 and represented by an arrow 38.
- the self-energizing direction of the wheel brakes of the wheels 30, 32, 34, 36 is shown with a triangle 40.
- the wheel brakes themselves are not shown in FIGS. 2 to 6.
- wheel brakes assigned to a front axle 42 have a self-reinforcing effect in the forward driving direction
- the wheel brakes assigned to a rear axle 44 have a self-reinforcing action in the reverse driving direction.
- the wheel brakes of the front axle 42 which have to exert the greatest braking force when braking when driving forward due to a weight distribution of the motor vehicle and a shift in weight when braking, have a self-reinforcing effect when driving forward.
- the wheel brakes assigned to the rear axle 44 act self-weakening when driving forward, their braking force is sufficient since the wheel brakes of the wheels 34, 36 of the rear axle 44 have to apply a considerably lower braking force when braking.
- the speed is lower than when driving forwards and, on the other hand, the dynamic axle load distribution is reversed, so that the braking force of the wheel brakes of the wheels 30, 32 of the front axle, which weaken when reversing, is sufficient.
- all four wheel brakes are self-energizing when driving forward. This enables a high braking force on all four vehicle wheels 30, 32, 34, 36 when driving forward. Since the driving speed is lower when driving in reverse and, in addition, a lower braking force is sufficient, sufficient braking of the motor vehicle with the four wheel brakes that weaken when reversing is still sufficient.
- the wheel brakes assigned to the front axle 42 have a self-reinforcing effect when driving forward.
- the wheel brakes assigned to the rear axle 44 have self- Reinforcement devices for both directions of rotation of the vehicle wheels 34, 36 and thus for both directions of travel of the motor vehicle.
- the self-reinforcing wheel brakes assigned to the rear axle 44 in both directions of travel are symbolized in FIG. 4 by two mutually opposite triangles 46 assembled on their base sides.
- This embodiment of the vehicle brake system according to the invention has the advantage that all four wheel brakes have a self-energizing effect when driving forward, in which the highest braking force is required. When reversing, the wheel brakes assigned to the rear axle 44 have a self-reinforcing effect.
- a disadvantage is the greater effort of wheel brakes, which have self-energizing devices for both directions of rotation.
- a second wedge 26 and a second inclined surface 28 are necessary, the inclination of which is opposite to that of the illustrated wedge 26 and the illustrated inclined surface 28.
- only the wheel brakes assigned to the front axle 42 have a self-boosting device which is effective when driving forward.
- the wheel brakes assigned to the rear axle 44 have no self-boosting device. They can be actuated electromechanically or, for example, hydraulically or pneumatically.
- the wheel brakes assigned to the front axle 42 have self-boosting devices for both directions of rotation and travel.
- the wheel brakes assigned to the rear axle 44 have a self-boosting device only for one direction of rotation and direction of travel; in the example shown, the self-boosting acts in the forward direction of travel.
- the wheel brakes assigned to the rear axle 44 can, conversely, have a self-reinforcing device that is only effective when reversing or no self-amplifying device at all.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Transportation (AREA)
- Braking Arrangements (AREA)
Abstract
The invention relates to a vehicle braking system with automatically boosted electromagnetic wheel brakes. According to the invention, the wheel brakes with automatic booster devices which are used are only effective in the direction of rotation i.e. exclusively in the direction of travel. The automatic booster devices of the wheel brakes associated with a front axle (42) are effective when travelling forwards. The automatic booster devices of the wheel brakes associated with a rear axle (44) are effective, for example, when travelling backwards.
Description
Fahrzeugbremsanlage vehicle brake system
Beschreibungdescription
Stand der TechnikState of the art
Die Erfindung betrifft eine Fahrzeugbremsanlage mit den Merkmalen des Oberbegriffs des Anspruchs 1. Die Fahrzeugbremsanlage ist insbesondere für Kraftfahrzeuge wie Personen- und Lastkraftwagen und Krafträder vorgesehen.The invention relates to a vehicle brake system with the features of the preamble of claim 1. The vehicle brake system is intended in particular for motor vehicles such as cars and trucks and motorcycles.
Es sind selbstverstärkende elektromechanische Radbremsen bekannt. Beispielsweise offenbart die DE 101 51 950 A1 eine derartige Bremse, die als Scheibenbremse ausgebildet ist. Zum Andrücken eines Reibbremsbelags weist die bekannte Radbremse eine elektromechanische Betätigungseinrichtung mit einem Elektromotor und einem Spindeltrieb als Rotations-/Translations- Umsetzungsgetriebe auf, mit dem der Reibbremsbelag verschiebbar und dadurch an eine Bremsscheibe drückbar ist. Der Reibbremsbelag liegt in einem Bremssattel ein, der in an sich bekannter Weise als sog. Schwimmsattel ausgeführt ist, d.h. er ist quer zur Bremsscheibe verschieblich. Ein zweiter Reibbremsbelag, der auf einer gegenüberliegenden Seite der Bremsscheibe wie der eine Reibbremsbelag im Bremssattel einliegt, wird beim Andrücken des einen Reibbremsbelags an die Bremsscheibe in an sich bekannter Weise durch Querverschiebung des Bremssattels an die andere Seite der Bremsscheibe
gedrückt. Es sind auch andere Konstruktionen elektromechanischer Betätigungseinrichtungen bekannt.Self-energizing electromechanical wheel brakes are known. For example, DE 101 51 950 A1 discloses such a brake, which is designed as a disc brake. To press a friction brake pad, the known wheel brake has an electromechanical actuating device with an electric motor and a spindle drive as a rotation / translation conversion gear, with which the friction brake pad can be displaced and can thus be pressed against a brake disc. The friction brake lining lies in a brake caliper, which is designed in a manner known per se as a so-called floating caliper, ie it can be displaced transversely to the brake disc. A second friction brake lining, which rests on an opposite side of the brake disc like the one friction brake lining in the brake caliper, is pressed in a manner known per se when the friction brake lining is pressed onto the brake disc by transverse displacement of the brake caliper to the other side of the brake disc pressed. Other designs of electromechanical actuators are also known.
Zur Selbstverstärkung weist die bekannte Reibbremse einen Keilmechanismus mit einem auf einer der Bremsscheibe angewandten Rückseite des einen Reibbremsbelags angeordneten Keil auf, der sich an einer Schrägfläche im Bremssattel abstützt, die mit einem einem Keilwinkel entsprechenden Winkel schräg zur Bremsscheibe verläuft. Zur Betätigung der Bremse verschiebt die elektromechanische Betätigungsein chtung den Reibbremsbelag in einer Drehrichtung der Bremsscheibe, die sich in Richtung eines enger werdenden Keilspalts zwischen der Schrägfläche und dem Bremssattel dreht. Der Reibbremsbelag bewegt sich schräg im Keilwinkel auf die Bremsscheibe zu und wird an diese gedrückt. Eine von der drehenden Bremsschreibe auf den Reibbremsbelag ausgeübte Reibungskraft beaufschlagt den Reibbremsbelag in Richtung des enger werdenden Keilspalts zwischen der Schrägfläche des Bremssattels und der Bremsscheibe. Durch die Abstützung des Reibbremsbelags über den Keil an der Schrägfläche übt die Schrägfläche dem sog. Keilprinzip entsprechend eine Abstützkraft auf den Keil aus, die eine Kraftkomponente quer zur Bremsscheibe aufweist. Diese Kraftkomponente quer zur Bremsscheibe stellt eine Andruckkraft dar, die den Reibbremsbelag zusätzlich zu einer von der Betätigungseinrichtung aufgebrachten Kraft an die Bremsscheibe andrückt und dadurch die Bremskraft erhöht. Es wird also nur ein Teil der zum Bremsen notwendigen Andruckkraft von der Betätigungseinrichtung aufgebracht, die übrige Andruckkraft wird von der Selbstverstärkungseinrichtung bewirkt.For self-reinforcement, the known friction brake has a wedge mechanism with a wedge arranged on a rear side of the one friction brake lining applied to the brake disc, which is supported on an inclined surface in the brake caliper, which extends obliquely to the brake disc at an angle corresponding to a wedge angle. To actuate the brake, the electromechanical actuating device moves the friction brake lining in a direction of rotation of the brake disc, which rotates in the direction of an increasingly wedge gap between the inclined surface and the brake caliper. The friction brake pad moves obliquely at a wedge angle towards the brake disc and is pressed against it. A frictional force exerted by the rotating brake disk on the friction brake lining acts on the friction brake lining in the direction of the widening wedge gap between the inclined surface of the brake caliper and the brake disc. By supporting the friction brake lining over the wedge on the inclined surface, the inclined surface, in accordance with the so-called wedge principle, exerts a supporting force on the wedge which has a force component transverse to the brake disc. This force component transverse to the brake disc represents a pressure force which presses the friction brake lining against the brake disc in addition to a force applied by the actuating device and thereby increases the braking force. Thus, only a part of the pressing force required for braking is applied by the actuating device, the remaining pressing force is brought about by the self-energizing device.
Anstelle eines Keilmechanismus kann beispielsweise auch ein Hebelmechanismus mit einem Hebel vorgesehen werden, der den Reibbremsbelag beim Bremsen in einem Winkel schräg zur Bremsscheibe abstützt. Ein Stützwinkel des Hebels entspricht dabei einem Keilwinkel des Keilmechanismus. Außer mechanischen Selbstverstärkungseinrichtungen sind beispielsweise auch hydraulische Selbstverstärkungseinrichtungen bekannt. Auch ist die Erfindung
nicht auf Scheibenbremsen als Radbremsen beschränkt, es können auch andere Bremsenbauformen Verwendung finden.Instead of a wedge mechanism, for example, a lever mechanism can also be provided with a lever which supports the friction brake lining at an angle to the brake disc when braking. A support angle of the lever corresponds to a wedge angle of the wedge mechanism. In addition to mechanical self-boosting devices, hydraulic self-boosting devices are also known, for example. The invention is also not limited to disc brakes as wheel brakes, other brake designs can also be used.
Ein Selbstverstärkungsfaktor ist bei einem Keilmechanismus unter der Annahme eines konstanten Reibwerts konstant. Durch Verwendung einer Rampe anstelle eines Keils, deren Rampenwinkel sich über ihren Verlauf ändert, lässt sich die Selbstverstärkung in Abhängigkeit von einem Verschiebeweg des Reibbremsbelags und damit abhängig von einer Betätigungs-, Andruck- und Bremskraft ändern. Beispielsweise wird durch einen großen Rampenwinkel am Beginn der Rampe eine schnelle Zustellung am Anfang einer Betätigung der Radbremse und durch einen kleinen Rampenwinkel am Ende der Rampe eine hohe Selbstverstärkung bei großer Andruck- und Bremskraft erreicht.A self-amplification factor is constant in a wedge mechanism assuming a constant coefficient of friction. By using a ramp instead of a wedge, the ramp angle of which changes over its course, the self-amplification can be changed as a function of a displacement path of the friction brake lining and thus as a function of an actuation, pressure and braking force. For example, a large ramp angle at the beginning of the ramp enables rapid infeed at the start of actuation of the wheel brake, and a small self-reinforcement with high pressure and braking force is achieved by a small ramp angle at the end of the ramp.
Eine weitere selbstverstärkende elektromechanische Radbremse offenbart die EP 953 785 A2. Während die vorstehend erläuterte Radbremse als Teilbelag- Scheibenbremse ausgebildet ist offenbart die genannte EP 953 785 A2 eine Vollbelag-Scheibenbremse mit einem Belagträgerring, der koaxial zu einer Bremsscheibe auf deren einer Seite angeordnet ist und der Reibbremsbeläge auf seiner der Bremsscheibe zugewandten Seite trägt. Auf einer der Bremsscheibe abgewandten Seite weist der Belagträgerring Keilelemente auf, die sich an drehbar und ortsfest gelagerten Walzen abstützen. Durch Drehen des Belagträgerrings gelangen die Keilelemente in Anlage an die Walzen, wodurch der Belagträgerring in Richtung der Bremsscheibe bewegt wird und die Reibbremsbeläge gegen die Bremsscheibe gedrückt werden. Auch hier ergibt sich die oben beschriebene Selbstverstärkung aufgrund des Keilprinzips. Die Keilelemente weisen einander entgegengesetzt schräge Keilflächen auf, so dass bei umgekehrter Drehrichtung der Bremsscheibe der Belagträgerring ebenfalls in umgekehrter Richtung, d.h. wieder in Drehrichtung der Bremsscheibe gedreht wird.Another self-energizing electromechanical wheel brake is disclosed in EP 953 785 A2. While the above-described wheel brake is designed as a partial-pad disc brake, EP 953 785 A2 discloses a full-pad disc brake with a pad carrier ring, which is arranged coaxially with a brake disc on one side and carries the friction brake pads on its side facing the brake disc. On a side facing away from the brake disc, the lining carrier ring has wedge elements, which are supported on rotatably and stationary mounted rollers. By turning the lining carrier ring, the wedge elements come into contact with the rollers, as a result of which the lining carrier ring is moved in the direction of the brake disk and the friction brake linings are pressed against the brake disk. Here, too, the self-reinforcement described above results from the wedge principle. The wedge elements have mutually oblique wedge surfaces, so that when the brake disc rotates in the opposite direction, the brake disc carrier ring also in the opposite direction, i.e. is turned again in the direction of rotation of the brake disc.
In der Praxis verwendete selbstverstärkende elektromechanische Radbremsen weisen stets eine Selbstverstärkungseinrichtung für eine und eine weitere
Selbstverstärkungseinrichtung für eine umgekehrte Drehrichtung, also beispielsweise zwei einander entgegengesetzt schräge Keilelemente auf, um eine Selbstverstärkungswirkung für Vor- und Rückwärtsfahrt zu haben. Der Keilwinkel und damit die Selbstverstärkung kann für Vor- und Rückwärtsfahrt gleich oder verschieden sein. Selbstverstärkungseinrichtungen für beide Drehrichtungen haben den Nachteil, dass die Radbremse aufwendiger in ihrer Konstruktion und damit teurer ist. Weiterer Nachteil ist, dass der Reibbremsbelag zur Betätigung der Radbremse immer in Drehrichtung verschoben werden muss um die Selbstverstärkung zu erzielen. Bei einer Verschiebung des Reibbremsbelags entgegen der Drehrichtung der Bremsscheibe ergäbe sich ohne zweite Selbstverstärkungseinrichtung eine Selbstschwächung der Andruck- und der Bremskraft, d.h. die Betätigungseinrichtung müsste eine höhere Betätigungskraft zur Erzielung einer bestimmten Andruckkraft des Reibbremsbelags gegen die Bremsscheibe aufbringen, als es ohne Selbstverstärkungseinrichtung der Fall wäre. Dies ist der Grund, weswegen für die praktische Anwendung in Kraftfahrzeugen ausschließlich Radbremsen mit Selbstverstärkung in beiden Drehrichtungen der Bremsscheibe in Betracht gezogen werden.Self-energizing electromechanical wheel brakes used in practice always have a self-energizing device for one and another Self-boosting device for a reverse direction of rotation, for example, two oppositely inclined wedge elements, in order to have a self-boosting effect for forward and backward travel. The wedge angle and thus the self-amplification can be the same or different for forward and reverse travel. Self-boosting devices for both directions of rotation have the disadvantage that the wheel brake is more complex in its construction and therefore more expensive. Another disadvantage is that the friction brake lining for actuating the wheel brake must always be moved in the direction of rotation in order to achieve self-reinforcement. If the friction brake lining were shifted counter to the direction of rotation of the brake disc, there would be a self-weakening of the pressure and braking force without a second self-reinforcing device, i.e. the actuating device would have to exert a higher actuating force to achieve a certain pressing force of the friction brake lining against the brake disk than would be the case without a self-reinforcing device , This is the reason why only wheel brakes with self-amplification in both directions of rotation of the brake disc are considered for practical use in motor vehicles.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Fahrzeugbremsanlage mit den Merkmalen des Anspruchs 1 weist Fahrzeugrädern zugeordnete selbstverstärkende elektromechanische Radbremsen auf. Dabei sieht die Erfindung vor, dass alle oder zumindest ein Teil der Radbremsen eine Selbstverstärkung nur für eine Fahrtrichtung aufweisen. Grundsätzlich kann die Fahrzeugbremsanlage auch als sog. Hybridbremsanlage ausgeführt sein, bei der nur ein Teil der Radbremsen elektromechanisch und andere Radbremsen hydraulisch oder in sonstiger Weise nicht-elektro- mechanisch betätigt werden.The vehicle brake system according to the invention with the features of claim 1 has self-energizing electromechanical wheel brakes assigned to vehicle wheels. The invention provides that all or at least some of the wheel brakes have self-amplification only for one direction of travel. In principle, the vehicle brake system can also be designed as a so-called hybrid brake system, in which only a part of the wheel brakes are actuated electromechanically and other wheel brakes are actuated hydraulically or in another way non-electromechanically.
Die Erfindung hat den Vorteil, dass durch Verwendung elektromechanischer Radbremsen mit Selbstverstärkung nur in einer Drehrichtung zumindest für einen Teil der Radbremsen konstruktiv einfachere und deswegen preisgünstiger
herstellbare Radbremsen Verwendung finden. Die Fahrzeugbremsanlage ist dadurch preisgünstiger. Weiterer Vorteil der Erfindung ist, dass für Radbremsen mit Selbstverstärkung nur in einer Drehrichtung keine Dreh- oder Fahrtrichtungserkennung zur Betätigung der Bremsen erforderlich ist, da der Reibbremsbelag zur Betätigung immer in derselben Richtung verschoben wird. Zusätzlicher Vorteil der Erfindung ist eine einfache Möglichkeit der Verschleißnachstellung. Beim Lösen der Radbremsen wird der Reibbremsbelag so weit zurückgestellt, dass sich ein gewünschtes Lüftspiel, d.h. ein gewünschter Spalt zwischen dem Reibbremsbelag und der Bremsscheibe, einstellt. Bei Verschleiß des Reibbremsbelags wird der Reibbremsbelag also nicht bis in seine ursprüngliche Ausgangslage bei unverschließenem Reibbremsbelag zurückbewegt. Ein Betätigungsweg zum Überwinden des Lüftspiels ist dadurch unabhängig vom Verschleiß des Reibbremsbelags und stets konstant. Eine Selbstschwächung bei umgekehrter Drehrichtung wird bei der erfindungs- gemäßen Fahrzeugbremsanlage in Kauf genommen. Dies ist akzeptabel, weil beispielsweise bei Rückwärtsfahrt wegen der dynamischen Achslastverlagerung an der Vorderachse eine vergleichsweise geringe Bremskraft ausreicht. Dabei ist zu bedenken, dass die Radbremsen für Höchstgeschwindigkeit bei Vorwärtsfahrt ausgelegt werden müssen, weswegen für Rückwärtsfahrt, die nur mit einem kleinen Bruchteil der Höchstgeschwindigkeit bei Vorwärtsfahrt erfolgt, eine erheblich geringere Bremskraft völlig ausreichend ist.The invention has the advantage that by using electromechanical self-energizing wheel brakes only in one direction of rotation, at least for some of the wheel brakes, it is structurally simpler and therefore cheaper manufacturable wheel brakes are used. The vehicle brake system is therefore cheaper. Another advantage of the invention is that for wheel brakes with self-amplification, only in one direction of rotation, no rotation or direction of travel detection is required to actuate the brakes, since the friction brake lining is always shifted in the same direction for actuation. An additional advantage of the invention is a simple possibility of adjusting the wear. When the wheel brakes are released, the friction brake lining is reset so far that a desired clearance, ie a desired gap between the friction brake lining and the brake disc, is established. If the friction brake lining wears, the friction brake lining is not moved back to its original starting position when the friction brake lining is unlocked. An actuation path to overcome the clearance is therefore independent of the wear of the friction brake lining and is always constant. A self-weakening in the opposite direction of rotation is accepted in the vehicle brake system according to the invention. This is acceptable because, for example, when driving backwards, a comparatively low braking force is sufficient due to the dynamic axle load shifting on the front axle. It should be borne in mind that the wheel brakes must be designed for maximum speed when driving forward, which is why a considerably lower braking force is completely sufficient for driving backwards, which is only a small fraction of the maximum speed when driving forward.
Anspruch 1 ist darauf gerichtet, dass einer Vorderachse eines Fahrzeugs zugeordnete Radbremsen eine nur in Vorwärtsfahrtrichtung wirksame Selbst- Verstärkung aufweisen. Es weisen also die Radbremsen, die jedenfalls bei Personenkraftwagen die höchste Bremskraft aufbringen müssen, eine Selbstverstärkung nur in Vorwärtsfahrtrichtung auf.Claim 1 is directed to the fact that wheel brakes assigned to a front axle of a vehicle have self-amplification which is effective only in the forward direction of travel. The wheel brakes, which in any case have to exert the highest braking force in passenger cars, have self-amplification only in the forward direction of travel.
Um für Rückwärtsfahrt ebenfalls eine Selbstverstärkungswirkung zu erzielen sieht Anspruch 2 vor, dass einer Hinterachse zugeordnete Radbremsen eine nur in Rückwärtsfahrtrichtung wirksame Selbstverstärkung aufweisen.
Anspruch 3 sieht im Unterschied dazu vor, dass der Hinterachse zugeordnete Radbremsen ebenso wie die der Vorderachse zugeordneten Radbremsen eine nur in Vorwärtsfahrtrichtung wirksame Selbstverstärkung aufweisen. Bei dieser Ausführungsform der Erfindung wird auf eine hohe Bremskraft in Vorwärts- fahrtrichtung an beiden Fahrzeugachsen wert gelegt, da hier die größten Bremskräfte erforderlich sind. Trotz der Selbstschwächung der Radbremsen bei Rückwärtsfahrt ist die Bremskraft für Rückwärtsfahrt ausreichend.In order to also achieve a self-boosting effect for reversing, claim 2 provides that wheel brakes assigned to a rear axle have a self-boosting that is effective only in the reverse direction. In contrast to this, claim 3 provides that the wheel brakes assigned to the rear axle as well as the wheel brakes assigned to the front axle have self-amplification which is effective only in the forward direction of travel. In this embodiment of the invention, a high braking force in the forward direction of travel on both vehicle axles is important, since the greatest braking forces are required here. Despite the self-weakening of the wheel brakes when reversing, the braking force is sufficient for reversing.
Anspruch 4 sieht vor, dass einer Hinterachse zugeordnete Radbremsen in beiden Fahrtrichtungen wirksame Selbstverstärkungseinrichtungen aufweisen. Bei dieser Ausführungsform der Erfindung werden also für die Hinterachse Radbremsen verwendet, die, wie in der Praxis üblich, eine Selbstverstärkung in beiden Fahrtrichtungen aufweisen. Dadurch weisen zumindest die Radbremsen einer Achse eine Selbstverstärkungswirkung auch bei Rückwärtsfahrt auf. Es müssen allerdings konstruktiv aufwendigere und teurere Radbremsen in Kauf genommen werden.Claim 4 provides that wheel brakes assigned to a rear axle have effective self-boosting devices in both directions of travel. In this embodiment of the invention, wheel brakes are used for the rear axle which, as is customary in practice, have self-amplification in both directions of travel. As a result, at least the wheel brakes of an axle have a self-boosting effect even when reversing. However, more complex and expensive wheel brakes have to be accepted.
Die Ausgestaltung gemäß Anspruch 5 sieht vor, dass einer Hinterachse zugeordnete Radbremsen keine Selbstverstärkungseinrichtung aufweisen. Hier ist also die Bremskraft der Radbremsen der Hinterachse unabhängig von einer Fahrtrichtung des Fahrzeugs. Solche Radbremsen sind wegen der fehlenden Selbstverstärkungseinrichtung konstruktiv einfacher und damit preisgünstiger.The embodiment according to claim 5 provides that wheel brakes assigned to a rear axle have no self-boosting device. Here, the braking force of the wheel brakes on the rear axle is independent of the direction of travel of the vehicle. Such wheel brakes are structurally simpler because of the lack of a self-energizing device and are therefore less expensive.
Der nebengeordnete Anspruch 8 sieht vor, dass einer Vorderachse zugeordnete elektromechanische Radbremsen eine in beiden Fahrtrichtungen wirksame Selbstverstärkung aufweisen und dass einer Hinterachse zugeordnete Radbremsen eine nur in einer Fahrtrichtung wirksame Selbstverstärkung aufweisen. Auch bei dieser Ausgestaltung der Erfindung ist eine Selbstverstärkungswirkung bei Rückwärtsfahrt an einer Fahrzeugachse, in diesem Fall an der Vorderachse, gegeben. An der Hinterachse werden konstruktiv einfachere und preisgünstigere Radbremsen verwendet. Ggf. können die der Hinterachse zugeordneten Radbremsen auch ohne Selbstverstärkungseinrichtung ausgeführt sein.
ZeichnungThe independent claim 8 provides that electromechanical wheel brakes assigned to a front axle have self-amplification effective in both directions of travel and that wheel brakes assigned to a rear axle have self-amplification effective only in one direction of travel. In this embodiment of the invention, too, there is a self-reinforcing effect when reversing on a vehicle axle, in this case on the front axle. On the rear axle, structurally simpler and less expensive wheel brakes are used. Possibly. The wheel brakes assigned to the rear axle can also be designed without a self-boosting device. drawing
Die Erfindung wird nachfolgend anhand in der Zeichnung dargestellter Ausführungsbeispiele näher erläutert. Die Zeichnungen sind als vereinfachte Schemadarstellungen zu verstehen. Es zeigen:The invention is explained in more detail below with reference to exemplary embodiments shown in the drawing. The drawings are to be understood as simplified schematic representations. Show it:
Figur 1 eine selbstverstärkende elektromechanische Scheibenbremse; undFigure 1 is a self-energizing electromechanical disc brake; and
Figuren 2 bis 6 Anordnungsmöglichkeiten selbstverstärkender elektromechanischer Radbremsen an Vorder- und Hinterachse eines Kraftwagens gemäß der Erfindung.Figures 2 to 6 possible arrangements of self-energizing electromechanical wheel brakes on the front and rear axles of a motor vehicle according to the invention.
Beschreibung der AusführungsbeispieleDescription of the embodiments
Die in Figur 1 dargestellte, erfindungsgemäße Radbremse ist als Scheibenbremse 10 ausgebildet. Sie weist einen Schwimmsattel 12 auf, der quer zu einer Bremsscheibe 14 verschieblich ist. Die Bremsscheibe 14 ist drehfest mit einem Fahrzeugrad 15 verbunden. Im Bremssattel 12 liegen beiderseits der Bremsscheibe 14 zwei Reibbremsbeläge 16, 18 ein, deren einer Reibbremsbelag 16 zum Bremsen mit einer elektromechanischen Betätigungseinrichtung 20 in einer Umfangs- oder Drehrichtung der Bremsscheibe 14 verschiebbar und deren anderer Reibbremsbelag 18 unverschieblich im Bremssattel 12 angeordnet ist. Die Betätigungseinrichtung 20 weist einen Elektromotor 22 auf, mit dem über einen Spindeltrieb 24 der Reibbremsbelag 16 verschieblich ist. Der Reibbremsbelag 16 stützt sich über einen Keil 26 an einer Schrägfläche 28 des Bremssattels 12 ab, er ist mit der Betätigungseinrichtung 20 entlang der Schrägfläche 28 verschiebbar.The wheel brake according to the invention shown in FIG. 1 is designed as a disc brake 10. It has a floating caliper 12 which is displaceable transversely to a brake disk 14. The brake disc 14 is rotatably connected to a vehicle wheel 15. In the brake caliper 12 there are two friction brake linings 16, 18 on both sides of the brake disc 14, one of which has a friction brake lining 16 for braking with an electromechanical actuating device 20 which can be displaced in a circumferential or rotational direction of the brake disc 14 and whose other friction brake lining 18 is arranged immovably in the brake caliper 12. The actuating device 20 has an electric motor 22 with which the friction brake lining 16 can be displaced via a spindle drive 24. The friction brake pad 16 is supported by a wedge 26 on an inclined surface 28 of the brake caliper 12, it can be displaced along the inclined surface 28 with the actuating device 20.
Zum Bremsen wird der Reibbremsbelag 16 mit der Betätigungseinrichtung 20 entlang der Schrägfläche 28 in Richtung eines enger werdenden Keilspalts zwischen der Schrägfläche 28 und der Bremsscheibe 14 verschoben. Der Reibbremsbelag 16 bewegt sich dadurch auf die Bremsscheibe 14 zu und wird an
diese gedrückt. Dabei wird der Bremssattel 12 in an sich bekannter Weise quer zur Bremsscheibe 14 verschoben und drückt den anderen Reibbremsbelag 18 an die andere Seite der Bremsscheibe 14, die dadurch gebremst wird. Die Bremsscheibe 14 beaufschlagt die beiden Reibbremsbeläge 16, 18 mit einer Reibungskraft, die in Drehrichtung der Bremsscheibe 14 gerichtet ist. Dreht sich die Bremsscheibe 14 in Richtung des enger werdenden Keilspalts zwischen der Schrägfläche 28 und der Bremsscheibe 14, bewirkt die von der drehenden Bremsscheibe 14 auf den an sie gedrückten, verschieblichen Reibbremsbelag 16 ausgeübte Reibungskraft durch die Abstützung an der Schrägfläche 28 nach dem sog. Keilprinzip eine Kraft mit einer Komponente quer zur Bremsscheibe 14. Diese Kraft drückt den Reibbremsbelag 16 zusätzlich zur Betätigungseinrichtung 20 an die Bremsscheibe 14, die Andruckkraft beider Reibbremsbeläge 16, 18 und damit die Bremskraft wird erhöht. Dieser Effekt wird als Selbstverstärkung bezeichnet. Die Scheibenbremse 10 weist mit dem Keil 26, der sich an der Schrägfläche 28 des Bremssattels 12 abstützt, eine mechanische Selbstverstärkungseinrichtung mit einem Keilmechanismus auf. Dreht sich die Bremsscheibe 14 in umgekehrter Drehrichtung bewirkt der Keilmechanismus eine Selbstschwächung, d.h. eine Andruckkraft der Reibbremsbeläge 16, 18 an die Bremsscheibe 14 und damit eine Bremskraft der Scheibenbremse 10 ist geringer als sie ohne den Keilmechanismus wäre.For braking, the friction brake pad 16 is displaced with the actuating device 20 along the inclined surface 28 in the direction of a wedge gap between the inclined surface 28 and the brake disk 14 that becomes narrower. The friction brake pad 16 thereby moves towards the brake disc 14 and is on pressed this. The brake caliper 12 is displaced transversely to the brake disc 14 in a manner known per se and presses the other friction brake lining 18 against the other side of the brake disc 14, which is thereby braked. The brake disc 14 acts on the two friction brake linings 16, 18 with a frictional force which is directed in the direction of rotation of the brake disc 14. If the brake disc 14 rotates in the direction of the narrowing wedge gap between the inclined surface 28 and the brake disc 14, the friction force exerted by the rotating brake disc 14 on the displaceable friction brake lining 16 pressed against it causes the support on the inclined surface 28 according to the so-called wedge principle a force with a component transverse to the brake disc 14. This force presses the friction brake pad 16 in addition to the actuating device 20 against the brake disc 14, the pressing force of both friction brake pads 16, 18 and thus the braking force is increased. This effect is called self-reinforcement. With the wedge 26, which is supported on the inclined surface 28 of the brake caliper 12, the disc brake 10 has a mechanical self-boosting device with a wedge mechanism. If the brake disc 14 rotates in the opposite direction of rotation, the wedge mechanism causes a self-weakening, ie a pressing force of the friction brake pads 16, 18 against the brake disc 14 and thus a braking force of the disc brake 10 is less than it would be without the wedge mechanism.
Die Figuren 2 bis 6 zeigen verschiedene Anordnungsmöglichkeiten einer selbstverstärkenden elektromechanischen Radbremse 10, wie sie in Figur 1 dargestellt ist, an Rädern 30, 32, 34, 36 eines im übrigen nicht dargestellten Kraftwagens, insbesondere eines Personenkraftwagens. Die Radbremsen des Personenkraftwagens müssen nicht zwingend die in Figur 1 schematisch und vereinfacht dargestellte Konstruktion aufweisen, es sind auch andere Bremsenkonstruktionen bekannt und möglich. Auch kann die Fahrzeugbremsanlage des Kraftwagens als Hybridbremsanlage ausgebildet sein, d.h. sie weist beispielsweise zwei elektromechanische Radbremsen 10, wie sie in Figur 1 dargestellt ist, an einer Fahrzeugachse und beispielsweise herkömmliche, hydraulische Radbremsen an der anderen Fahrzeugachse auf. Eine
Vorwärtsfahrtrichtung des Kraftwagens ist in Figuren 2 bis 6 nach links angenommen und mit einem Pfeil 38 dargestellt. Die Selbstverstärkungsrichtung der Radbremsen der Räder 30, 32, 34, 36 ist jeweils mit einem Dreieck 40 dargestellt. Die Radbremsen selbst sind in Figuren 2 bis 6 nicht dargestellt.FIGS. 2 to 6 show different possible arrangements of a self-energizing electromechanical wheel brake 10, as shown in FIG. 1, on wheels 30, 32, 34, 36 of a motor vehicle, not shown, in particular a passenger car. The wheel brakes of the passenger car do not necessarily have to have the construction shown schematically and simplified in FIG. 1, other brake designs are also known and possible. The vehicle brake system of the motor vehicle can also be designed as a hybrid brake system, ie it has, for example, two electromechanical wheel brakes 10, as shown in FIG. 1, on one vehicle axle and, for example, conventional hydraulic wheel brakes on the other vehicle axle. A The forward driving direction of the motor vehicle is assumed to the left in FIGS. 2 to 6 and represented by an arrow 38. The self-energizing direction of the wheel brakes of the wheels 30, 32, 34, 36 is shown with a triangle 40. The wheel brakes themselves are not shown in FIGS. 2 to 6.
Bei der in Figur 2 dargestellten Fahrzeugbremsanlage wirken einer Vorderachse 42 zugeordnete Radbremsen in Vorwärtsfahrtrichtung selbstverstärkend, die einer Hinterachse 44 zugeordneten Radbremsen wirken in Rückwärtsfahrtrichtung selbstverstärkend. Es wirken also die Radbremsen der Vorderachse 42, die beim Bremsen bei Vorwärtsfahrt aufgrund einer Gewichtsverteilung des Kraftwagens und einer Gewichtsverlagerung beim Bremsen die größte Bremskraft aufzubringen haben, bei Vorwärtsfahrt selbstverstärkend. Obwohl die der Hinterachse 44 zugeordneten Radbremsen bei Vorwärtsfahrt selbstschwächend wirken, reicht ihre Bremskraft aus, da die Radbremsen der Räder 34, 36 der Hinterachse 44 beim Bremsen eine erheblich geringere Bremskraft aufbringen müssen. Bei einer Rückwärtsfahrt ist zum einen die Geschwindigkeit niedriger als bei Vorwärtsfahrt und zum anderen kehrt sich die dynamische Achslastverteilung um, so dass die Bremskraft der bei Rückwärtsfahrt selbstschwächenden Radbremsen der Räder 30, 32 der Vorderachse ausreicht.In the vehicle brake system shown in FIG. 2, wheel brakes assigned to a front axle 42 have a self-reinforcing effect in the forward driving direction, the wheel brakes assigned to a rear axle 44 have a self-reinforcing action in the reverse driving direction. The wheel brakes of the front axle 42, which have to exert the greatest braking force when braking when driving forward due to a weight distribution of the motor vehicle and a shift in weight when braking, have a self-reinforcing effect when driving forward. Although the wheel brakes assigned to the rear axle 44 act self-weakening when driving forward, their braking force is sufficient since the wheel brakes of the wheels 34, 36 of the rear axle 44 have to apply a considerably lower braking force when braking. When driving in reverse, the speed is lower than when driving forwards and, on the other hand, the dynamic axle load distribution is reversed, so that the braking force of the wheel brakes of the wheels 30, 32 of the front axle, which weaken when reversing, is sufficient.
Bei der in Figur 3 dargestellten Fahrzeugbremsanlage wirken alle vier Radbremsen bei Vorwärtsfahrt selbstverstärkend. Dadurch ist eine hohe Bremskraft an allen vier Fahrzeugrädern 30, 32, 34, 36 bei Vorwärtsfahrt möglich. Da bei Rückwärtsfahrt die Fahrgeschwindigkeit niedriger ist und außerdem eine geringere Bremskraft ausreicht ist eine ausreichende Bremsung des Kraftwagens mit den bei Rückwärtsfahrt selbstschwächenden vier Radbremsen immer noch ausreichend.In the vehicle brake system shown in FIG. 3, all four wheel brakes are self-energizing when driving forward. This enables a high braking force on all four vehicle wheels 30, 32, 34, 36 when driving forward. Since the driving speed is lower when driving in reverse and, in addition, a lower braking force is sufficient, sufficient braking of the motor vehicle with the four wheel brakes that weaken when reversing is still sufficient.
Bei der in Figur 4 dargestellten Fahrzeugbremsanlage wirken die der Vorderachse 42 zugeordneten Radbremsen bei Vorwärtsfahrt selbstverstärkend. Die der Hinterachse 44 zugeordneten Radbremsen weisen Selbst-
Verstärkungseinrichtungen für beide Drehrichtungen der Fahrzeugräder 34, 36 und somit für beide Fahrtrichtungen des Kraftwagens auf. Die in beiden Fahrtrichtungen selbstverstärkenden, der Hinterachse 44 zugeordneten Radbremsen sind in Figur 4 durch zwei einander entgegengerichtete, an ihren Grundseiten zusammengesetzte Dreiecke 46 symbolisiert. Diese Ausgestaltung der erfindungsgemäßen Fahrzeugbremsanlage hat den Vorteil, dass alle vier Radbremsen bei Vorwärtsfahrt, bei der die höchste Bremskraft erforderlich ist, selbstverstärkend wirken. Bei Rückwärtsfahrt wirken die der Hinterachse 44 zugeordneten Radbremsen selbstverstärkend. Von Nachteil ist der größere Aufwand von Radbremsen, die Selbstverstärkungseinrichtungen für beide Drehrichtungen aufweisen. Es ist dazu bei der in Figur 1 dargestellten Radbremse 10 ein zweiter Keil 26 und eine zweite Schrägfläche 28 notwendig, deren Schräge denjenigen des dargestellten Keils 26 und der dargestellten Schrägfläche 28 entgegengerichtet ist.In the vehicle brake system shown in FIG. 4, the wheel brakes assigned to the front axle 42 have a self-reinforcing effect when driving forward. The wheel brakes assigned to the rear axle 44 have self- Reinforcement devices for both directions of rotation of the vehicle wheels 34, 36 and thus for both directions of travel of the motor vehicle. The self-reinforcing wheel brakes assigned to the rear axle 44 in both directions of travel are symbolized in FIG. 4 by two mutually opposite triangles 46 assembled on their base sides. This embodiment of the vehicle brake system according to the invention has the advantage that all four wheel brakes have a self-energizing effect when driving forward, in which the highest braking force is required. When reversing, the wheel brakes assigned to the rear axle 44 have a self-reinforcing effect. A disadvantage is the greater effort of wheel brakes, which have self-energizing devices for both directions of rotation. For this purpose, in the wheel brake 10 shown in FIG. 1, a second wedge 26 and a second inclined surface 28 are necessary, the inclination of which is opposite to that of the illustrated wedge 26 and the illustrated inclined surface 28.
Bei der in Figur 5 dargestellten Fahrzeugbremsanlage weisen nur die der Vorderachse 42 zugeordneten Radbremsen eine Selbstverstärkungseinrichtung auf, die bei Vorwärtsfahrt wirksam ist. Die der Hinterachse 44 zugeordneten Radbremsen weisen keine Selbstverstärkungseinrichtung auf. Sie können elektromechanisch oder beispielsweise auch hydraulisch oder pneumatisch betätigbar sein.In the vehicle brake system shown in FIG. 5, only the wheel brakes assigned to the front axle 42 have a self-boosting device which is effective when driving forward. The wheel brakes assigned to the rear axle 44 have no self-boosting device. They can be actuated electromechanically or, for example, hydraulically or pneumatically.
Bei der in Figur 6 dargestellten Fahrzeugbremsanlage weisen die der Vorderachse 42 zugeordneten Radbremsen Selbstverstärkungseinrichtungen für beide Dreh- und Fahrtrichtungen auf. Die der Hinterachse 44 zugeordneten Radbremsen weisen eine Selbstverstärkungseinrichtung nur für eine Dreh- und Fahrtrichtung auf, im dargestellten Beispiel wirkt die Selbstverstärkung in Vorwärtsfahrtrichtung. Die der Hinterachse 44 zugeordneten Radbremsen können allerdings auch umgekehrt eine nur bei Rückwärtsfahrt wirksame Selbstver- Stärkungseinrichtung oder gar keine Selbstverstärkungseinrichtung aufweisen.
In the vehicle brake system shown in FIG. 6, the wheel brakes assigned to the front axle 42 have self-boosting devices for both directions of rotation and travel. The wheel brakes assigned to the rear axle 44 have a self-boosting device only for one direction of rotation and direction of travel; in the example shown, the self-boosting acts in the forward direction of travel. Conversely, the wheel brakes assigned to the rear axle 44 can, conversely, have a self-reinforcing device that is only effective when reversing or no self-amplifying device at all.
Claims
1. Fahrzeugbremsanlage mit selbstverstärkenden elektromechanischen Radbremsen, dadurch gekennzeichnet, dass einer Vorderachse (42) zugeordnete Radbremsen eine nur in Vorwärtsfahrtrichtung wirksame Selbstverstärkung aufweisen.1. Vehicle brake system with self-energizing electromechanical wheel brakes, characterized in that wheel brakes assigned to a front axle (42) have self-amplification that is effective only in the forward direction of travel.
2. Fahrzeugbremsanlage nach Anspruch 1 , dadurch gekennzeichnet, dass einer Hinterachse (44) zugeordnete Radbremsen eine nur in Rückwärtsfahrtrichtung wirksame Selbstverstärkung aufweisen.2. Vehicle brake system according to claim 1, characterized in that a rear axle (44) associated wheel brakes have an effective self-amplification only in the reverse direction.
3. Fahrzeugbremsanlage nach Anspruch 1 , dadurch gekennzeichnet, dass einer Hinterachse (44) zugeordnete Radbremsen eine nur in Vorwärtsfahrtrichtung wirksame Selbstverstärkung aufweisen.3. Vehicle brake system according to claim 1, characterized in that a rear axle (44) associated wheel brakes have an effective self-amplification only in the forward direction.
4. Fahrzeugbremsanlage nach Anspruch 1 , dadurch gekennzeichnet, dass einer Hinterachse (44) zugeordnete Radbremsen in beiden Fahrtrichtungen wirksame Selbstverstärkungen aufweisen.4. Vehicle brake system according to claim 1, characterized in that a rear axle (44) associated wheel brakes have effective self-reinforcements in both directions of travel.
5. Fahrzeugbremsanlage nach Anspruch 1 , dadurch gekennzeichnet, dass einer Hinterachse (44) zugeordnete Radbremsen keine Selbstverstärkung aufweisen. 5. Vehicle brake system according to claim 1, characterized in that a rear axle (44) associated wheel brakes have no self-amplification.
6. Fahrzeugbremsanlage nach Anspruch 1 , dadurch gekennzeichnet, dass die Radbremsen (10) eine mechanische Selbstverstärkungseinrichtung (26, 28) aufweisen.6. Vehicle brake system according to claim 1, characterized in that the wheel brakes (10) have a mechanical self-boosting device (26, 28).
7. Fahrzeugbremsanlage nach Anspruch 6, dadurch gekennzeichnet, dass die Selbstverstärkungseinrichtung (26, 28) einen Keilmechanismus aufweist.7. Vehicle brake system according to claim 6, characterized in that the self-boosting device (26, 28) has a wedge mechanism.
8. Fahrzeugbremsanlage mit selbstverstärkendem elektromechanischen Radbremsen, dadurch gekennzeichnet, dass einer Vorderachse (42) zugeordnete Radbremsen eine in beiden Fahrtrichtungen wirksame Selbstverstärkung aufweisen und dass einer Hinterachse (44) zugeordnete Radbremsen eine nur in einer Fahrtrichtung wirksame Selbstverstärkung aufweisen. 8. Vehicle brake system with self-energizing electromechanical wheel brakes, characterized in that wheel brakes assigned to a front axle (42) have self-amplification that is effective in both directions of travel and that a rear axle (44) assigned wheel brakes have self-amplification that is effective only in one direction of travel.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10338449A DE10338449A1 (en) | 2003-08-21 | 2003-08-21 | Vehicle braking system with self-boosting electromechanical wheel brakes has self- boosting only effective in forward direction of travel for front axle brakes, in reversing, forward, both or no directions for rear axle brakes |
PCT/DE2004/001384 WO2005026571A1 (en) | 2003-08-21 | 2004-07-01 | Vehicle braking system |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1658445A1 true EP1658445A1 (en) | 2006-05-24 |
Family
ID=34201795
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP04738830A Withdrawn EP1658445A1 (en) | 2003-08-21 | 2004-07-01 | Vehicle braking system |
Country Status (6)
Country | Link |
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US (1) | US20070000738A1 (en) |
EP (1) | EP1658445A1 (en) |
JP (1) | JP2007506908A (en) |
CN (1) | CN1839269A (en) |
DE (1) | DE10338449A1 (en) |
WO (1) | WO2005026571A1 (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102006029943B4 (en) * | 2006-03-28 | 2008-04-17 | Knorr-Bremse Systeme für Nutzfahrzeuge GmbH | Disc brake in self-reinforcing design and method for their control |
DE102006051141A1 (en) * | 2006-10-30 | 2008-05-08 | Siemens Ag | Machine tool, production machine and / or handling machine |
DE102006058565A1 (en) | 2006-12-12 | 2008-06-19 | Siemens Ag | Balanced wedge control |
DE102007020503A1 (en) | 2007-05-02 | 2008-11-06 | Robert Bosch Gmbh | Hydraulic vehicle brake system and method for its operation |
JP2009234426A (en) * | 2008-03-27 | 2009-10-15 | Akebono Brake Ind Co Ltd | Self-boosting disc brake system |
DE102009041449A1 (en) * | 2008-09-27 | 2010-04-01 | Continental Teves Ag & Co. Ohg | Combined vehicle brake system with hydraulically and electromechanically actuated wheel brakes |
CN109469692A (en) * | 2018-12-14 | 2019-03-15 | 刘青 | A kind of double disc brake pan brakes |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE69836301T2 (en) * | 1997-07-29 | 2007-06-06 | Toyota Jidosha Kabushiki Kaisha, Toyota | Electrically operated brake system with an electric brake motor actuator for obtaining a relationship between engine power and braking torque |
DE19819564C2 (en) * | 1998-04-30 | 2000-06-08 | Deutsch Zentr Luft & Raumfahrt | Self-energizing electromechanical brake |
DE19850257C2 (en) * | 1998-10-31 | 2002-09-19 | Daimler Chrysler Ag | Disc brake protection of a disc brake of a motor vehicle wheel with a perforated rim disk |
DE50301865D1 (en) * | 2002-04-26 | 2006-01-12 | Estop Gmbh | MOTOR BRAKING SYSTEM WITH PARK BRAKE FUNCTION AND ELECTROMECHANICAL WHEEL BRAKES FOR SUCH A MOTOR VEHICLE BRAKING SYSTEM |
-
2003
- 2003-08-21 DE DE10338449A patent/DE10338449A1/en not_active Withdrawn
-
2004
- 2004-07-01 JP JP2006515696A patent/JP2007506908A/en not_active Withdrawn
- 2004-07-01 WO PCT/DE2004/001384 patent/WO2005026571A1/en active Application Filing
- 2004-07-01 EP EP04738830A patent/EP1658445A1/en not_active Withdrawn
- 2004-07-01 CN CNA2004800239816A patent/CN1839269A/en active Pending
- 2004-07-01 US US10/556,595 patent/US20070000738A1/en not_active Abandoned
Non-Patent Citations (1)
Title |
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See references of WO2005026571A1 * |
Also Published As
Publication number | Publication date |
---|---|
CN1839269A (en) | 2006-09-27 |
DE10338449A1 (en) | 2005-03-17 |
WO2005026571A1 (en) | 2005-03-24 |
JP2007506908A (en) | 2007-03-22 |
US20070000738A1 (en) | 2007-01-04 |
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