• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a braking device with a control unit for braking a drawbar trailer with a front axle (18) and one or more additional axles (20), each axle having at least two wheels. The purpose of the invention is, among other things, to achieve a axle load-dependent braking force distribution on any number of axles on a drawbar trailer with a simple built-up braking device while maintaining a stable condition of the vehicle. of the determined axle load on the front axle (18) and on the additional axle (20) and of the brake signals received from the towing vehicle, thereby activating adjusting means (44) so that the determined brake pressure is delivered with the same magnitude to the front axle (18) and to the or the additional axles (20). (Fig. 1)
    公开号:SE533824C2
    申请号:SE0900466
    申请日:2009-04-08
    公开日:2011-01-25
    发明作者:Holger Barlsen；Norbert Witte；Axel Stender；Markus Wolf；Ingo Tha
    申请人:Wabco Gmbh；
    IPC主号:
    专利说明:

    25 30 35 40 533 824 2 in the load, and thus in the grip, between the wheels on one axle is considerably smaller than the difference between the wheels on different axles. It is therefore acceptable to apply the same braking force to the wheels on a given axle. In this way, the associated braking system can be made simpler, and thus cheaper. In the case of axle loads, these are divided into a static component, which is present when the vehicle is stationary or when it is not braking or accelerated while driving, and a dynamic component, which is superimposed on the static component during driving with the vehicle.
    The static component is mainly determined by the vehicle's construction and geometric structure and by the load. The dynamic component is determined above all by acceleration and deceleration processes. The sum of the static and dynamic components of the axle load is denoted by the instantaneous axle load, which is dependent on the acceleration and deceleration and which significantly affects the current grip during braking.
    When, for example, braking a vehicle driving in the forward direction with two axles and with the center of gravity located above the axle height, the load on the fi frame axle increases, while the rear axle is relieved by the same value. This value depends on the size of the deceleration, the static axle loads on the front and rear axles and the geometric structure of the vehicle (for example, the length and position of the vehicle's center of gravity). In order to be able to brake the vehicle optimally, knowledge of the instantaneous axle load on each vehicle axle is required. One possibility would be to determine the instantaneous axle load with an axle load sensor arranged on each axle. However, this is complicated and expensive. A simplification consists in determining the instantaneous shaft load for only one of the shafts. In this case, a first signal is recorded during travel without braking and acceleration, which corresponds to the static axle load, and a second signal, which is registered during braking and corresponds to the instantaneous axle load. From the difference between the instantaneous and static axle loads, conclusions can be drawn about the instantaneous axle load on the other axle, which is not equipped with an axle load sensor, if the distribution of the static axle load between the front axle and the second axle is known. The distribution of the static axle loads is generally known, since it is of great importance in the construction of the drawbar trailer.
    Alternatively, it can be determined with a test device, for example at the factory.
    However, it is only in vehicles with two axles that it is possible to draw conclusions about the instantaneous axle load on the other axle with knowledge of the instantaneous axle load on one axle. If there are axles, additional axle load sensors must be provided.
    A way of not having to use additional axle load sensors is described in DE 19 707 210. The brake crates are determined here with a single axle load sensor, but in addition the rotational speeds of the individual vehicle wheels are considered instead of the instantaneous axle load of the additional axles being fitted with additional axle load sensors. Based on the differences between the rotational speeds of the individual vehicle axles, a slip difference is determined, which is used to determine the braking force. In this case, each wheel is assigned an optimal braking pressure, which in turn makes the braking device complicated.
    In the case of drawbar trailers, a 4S / 3M configuration is preferably used. Two wheel sensors and an EBS valve are used for the steering shaft 10 15 20 25 30 35 40 533 824 3. An EBS valve is a valve that can deliver a brake pressure automatically. The wheel that first shows the locking tendency dominates the ABS control on the axle viewed. This adjustment takes place according to the principle of modified shaft adjustment (MAR). For each additional axle, an ABS modulator and a pressure control channel are used in an EBS modulator for individual control of the individual wheels. Known braking devices of this type have a three-channel brake pressure control and a three-channel ABS control, which means that the cost is not competitive.
    WO 03/011664 describes a braking system for trailers for commercial vehicles which have a steerable fi-ania axle. With this braking system, the number of axle load sensors can be reduced by allowing the system to be operated even without the front axle having an axle load sensor (pressure sensor). The disadvantage of a braking system of this kind is that the front axle cannot be braked electronically if the towing vehicle does not provide a compressed air brake pressure. With a system of this kind, it is not possible to carry out a stability control, since such a system requires the wheels to be maneuverable independently of the driver's wishes.
    The object of the invention is to provide a braking device with which it is possible to achieve a axle load-dependent braking force distribution on any number of axles on a drawbar trailer while maintaining a stable condition of the vehicle, the braking device being composed of as few components and as simple as possible. .
    Furthermore, it must be possible to provide an electronic braking even in the event that no compressed air control pressure is provided by the towing vehicle.
    The object is fulfilled according to the invention in that the control unit of the initially specified brake device determines the magnitude of the brake pressure for the operation of the brake means as a function of the determined axle load on the fi axle and on the one or ytterligare additional axles as well as of the received brake signals. the specified bromine pressure is provided. The control unit thus determines only a single brake pressure, whereby the working pressure present in the pressure supply only needs to be adapted to a single brake pressure. Thus, only a single component is required for the pressure adjustment. With this brake pressure, all the brake members on the drawbar trailer can be activated and no separate determination of the brake pressure is required for each axle on the vehicle. Thus, a central supply is sufficient, with which the brake pressure is supplied to the brake means, which helps to simplify and obviate the braking device. The fewer leads that are needed, the lower the risk of errors, which generally increases with the number of components and the cable length. Furthermore, the calculation steps to be performed by the control unit become less extensive than in conventional embodiments, since what needs to be determined is only one brake pressure for the entire brake device and not an individual brake pressure for each wheel to be braked. The braking pressure is calculated from the average value of the determined axle loads. Even when the axle load on the front axle and the additional axles are different, only a single brake pressure is determined. The same brake pressure is thus emitted on the axles, and thus on the wheels.
    In order for the wear on the brake pads of the brake means to be evenly distributed despite this, it is suitable to use the same type of brake cylinders on all axles. As a result, the control unit can be partly simple in construction and partly in comparison with the case of previously known embodiments carry out fl your calculation operations during the same time. The determined braking pressure can therefore be adapted at more frequent intervals to the rapidly varying driving conditions of the vehicle, whereby the determined braking pressure can take into account the current driving conditions with very little time delay without the need to increase the calculation capacity.
    In this way an important contribution is obtained to increase the traffic safety of the vehicle at the same time as the cost of the braking device according to the invention becomes lower.
    A preferred embodiment of the invention consists in that one of the first sensor means is arranged for the front axle. In this embodiment, the braking device has only a single first sensor means. All the information needed for a safe braking of the drawbar trailer can be obtained by means of the other sensor means. Thereby, the number of first sensor means can be reduced to a minimum to minimize the cost of the braking device. Furthermore, the reduction in the number of first sensor means means that the wiring is simplified, which reduces the risk of incorrect wiring.
    The other sensor means for determining the speed of the wheels are already available in modern series-manufactured trailers and are used, for example, for ABS control. A reduction in the number of other sensor means would not appreciably affect the cost of the braking device and furthermore a locking of the wheels can be safely detected only by means of the rotational speed, whereby a reduction of the other components would not be expedient and an ABS control of all liiul not would be possible. This would counteract the effort to increase driving safety.
    The first sensor means are preferably designed as pressure sensors or road sensors. Sensors of this kind are common in the automotive industry and are therefore manufactured in long series, whereby they can be purchased at low cost. Furthermore, sensors of this type are characterized by high reliability, which increases the functional safety of the braking device.
    Modern commercial vehicles often contain sensors of this kind, for example to monitor the maximum permissible load or to monitor the height of the superstructure, whereby this embodiment of the present invention can utilize already significant sensors. The vehicle does not need to be equipped with additional sensor equipment and there are no significant additional costs.
    According to a preferred embodiment of the invention, the other sensor means comprise a pole wheel and an ABS sensor. Thereby, the rotational speeds of the vehicle wheels can be easily determined. Components of this kind are now part of the standard equipment in vehicles. It is thus possible to utilize existing components without adding additional sensor equipment. This embodiment thus also makes a contribution to reducing the cost of the braking device according to the invention.
    According to the invention, the other sensor means are designed to form sensor signals relating to the shaft load on the one or more additional shafts. Sensor means for generating sensor signals relating to the axle load can thus be arranged not only on the front axle, but also on at least the other axle or on all axles. These signals can be used to indicate the axle load for each axle. In some cases the driver must have precise knowledge of the axle load on all axles, for example to avoid too much of a heavy load being concentrated on a single axle. Furthermore, the signal may show the driver that the load has been shifted to a critical position for the vehicle's driving characteristics and that a change of the load may be required. In this way, critical load conditions can be detected and remedied. The second sensor means can in this case have an identical structure as the first sensor means and for instance consist of pressure sensors or wall sensors.
    A preferred embodiment of the invention is characterized in that the means for adapting the working pressure to the brake pressure and the control unit are combined into an EBS modulator. EBS modulators are also common in the automotive industry, and are thus mass-produced components, which are inexpensive to purchase. By bringing components together, it is achieved that the structure of the braking device can be simplified by making the connecting lines between the two components shorter or omitting them completely, which makes a positive contribution to drive safety. Connecting cables have the disadvantage that during the operation of the vehicle they are exposed to great stresses (for example temperature variations, an aggressive environment caused by salt), whereby they can be damaged and become inoperable.
    If they can be made shorter or if they can be arranged inside a component, ideally inside a protective housing, this problem can at least be reduced. Another disadvantage is that with increasing number of components, the wiring between them becomes more complicated, and thus more difficult. By bringing the components together into a modulator, the assembly is also simplified by the fact that the EBS modulator can be prefabricated and function tested before it is installed. This reduces the risk of incorrect wiring connections.
    The braking device according to the invention preferably has a brake pressure reducer associated with a axle or a wheel in order to lower the brake pressure as a function of the rotational speed of the axle or wheel to be braked. Since the EBS modulator or control unit, based on the average value of the determined axle loads, only calculates and maintains a single brake pressure, which can be applied to the brakes for the wheels on the additional axles, this pressure may become too high for some wheels. which would cause the affected wheels to lock. This can be prevented by using the brake pressure reducer to lower the brake pressure for the affected axle in such a way that locking of the wheels is prevented. The brake pressure reducer lowers the brake pressure only in the event that a wheel actually also locks. Thus, a high driving safety can be ensured during braking without the complexity of the braking device's construction needs to increase appreciably. In particular, the advantage is maintained that the control unit or the EBS modulator determines only a single brake pressure and that this can be supplied via a central line to the brake means for the additional axles.
    The brake pressure reducer is preferably designed as an ABS modulator. Components of this kind are also common in the automotive industry, and are thus mass-produced components. They are technically mature and therefore have high reliability at low cost. They make it possible to lower the brake pressure as a direct function of the wheel speed in such a way that locking of the affected wheels is prevented. This can be achieved, for example, by activating a solenoid valve in the ABS modulator in a suitable manner by a control unit, for example the EBS modulator. In this case, only the brake pressure applied to the brake means for the wheel or axle concerned, which belongs to the ABS modulator, is lowered and not the brake pressure applied to the other brake means.
    Another preferred embodiment of the invention consists in that the EBS modulator is arranged for the front axle and an ABS modulator is arranged for all other axles or an ABS modulator is arranged for each additional axle. This means that the brake members for a shaft belonging to a modulator are directly connected to the modulator through electrical or pneumatic lines. It is convenient to arrange the modulators in physical proximity to the associated shafts, so that the wires can be made as short as possible. In addition, since the EBS modulator is connected to the towing vehicle by electrical and pneumatic lines, it is also convenient to arrange the EBS modulator for the front axle and place it in its vicinity, since the lines to the towing vehicle can thereby be made short. It is generally known that the exposure to wires increases with length. A reduced cable length therefore contributes to increasing the operating reliability.
    Depending on the requirements, an ABS modulator can be arranged for each additional axle, so that the brake pressure can be reduced as a function of the rotational speed of the wheels on each axle. The reading of the wheels can thus be prevented separately for each additional axle, which makes it possible to combine high traffic safety with high braking ability. However, the disadvantage in this case is that an additional ABS modulator must be provided for each additional shaft. As a result, costs will be higher, which may face opposition from the market.
    The costs can also be reduced by arranging a single ABS modulator regardless of the number of additional axles, whereby this ABS modulator lowers the brake pressure based on the rotational speed of the wheels on all the additional axles. Also in this way a locking of the wheels can be prevented, but the disadvantage is that the brake pressure is lowered already when one of the wheels starts to lock. Provided that the vehicle is evenly loaded and moves around, the load on the rear axle decreases most during braking, which means that the wheels on this axle are the ones that tend to lock first. Thus, if a single ABS modulator is provided for all other axles, it will in this position lower the brake pressure in such a way that even the wheels which have not yet locked are supplied with a reduced brake pressure.
    These wheels are thus not supplied with the maximum possible braking force and the maximum possible deceleration is not achieved. However, this problem is relatively small, since the additional axles in the case that the drawbar trailer has fl such axles are usually physically close to each other. The axle loads on the further axles will therefore not differ significantly from each other, whereby also the traction of the individual additional axles becomes relatively similar and the wheels belonging to the axles can also be braked with approximately the same maximum brake laughter. The possible braking force which is not utilized by arranging only a single ABS modulator is thus within acceptable limits, whereby a construction of this kind can also be considered acceptable.
    According to a particularly preferred embodiment of the invention, the maximum size of the determined braking pressure is determined by the maximum traction of the wheels on the front axle. This is based on the idea that the front axle is the axle that is most heavily loaded during braking, so that the wheels on the front axle provide the highest traction, seen over the vehicle. The braking pressure determined by the EBS modulator will thus be at least equal to or at least higher than the pressure required to lock the wheels on the other axles. This ensures that the determined brake pressure is always what allows the brake means to be operated according to the highest available traction. If the determined braking pressure should lead to the wheels on the additional axles locking, this can be prevented in the manner described above.
    A further preferred embodiment is characterized in that it has a pressure circuit which provides the full working pressure to the further shafts. Such an embodiment of the braking device is suitable in the case that the braking pressure determined by the EBS modulator just prevents the front wheels from locking, while the wheels on the further axles have not yet locked even though the associated braking means are operated with the determined braking pressure. . In this situation, the wheels on the additional axles could thus be braked with a higher braking force than is achieved with the determined braking pressure. Such a situation could arise if the vehicle is abnormally heavily loaded over the additional axles, ie. mainly in the rear part, so that the wheels belonging to these axles even during braking have better grip than the wheels on the front axles. With the aid of the pressure circuit, the full working pressure available in the pressure accumulator can be supplied to the further axles, whereby a maximum possible brake circuit fl can be supplied to the affected wheels. In this way it is ensured that the wheels can be braked according to the maximum traction even in unusual load conditions.
    A preferred embodiment of the invention consists in that the braking means comprise brake cylinders and wheel brakes arranged on the wheels. Components of this kind are common in the automotive industry, especially in commercial vehicles, in that they are characterized by high reliability and low complexity. The wheel brakes can in the usual way be designed as drum or disc brakes, which can be operated by the brake cylinder via a control rod.
    A preferred further embodiment of the invention consists in that the EBS modulator is supplied with information about the state of movement of the towing vehicle and / or that the first and second sensor signals can be supplied to the towing vehicle by means of the transfer unit. Modern towing vehicles increasingly have braking systems which, when braking, must take into account a large amount of information about the towing vehicle's movement condition, such as the own vehicle's speed, turning speed, distance to the vehicle in front, etc. For a correct description of the towing vehicle's movement condition, it is also important to take consideration of 10 15 20 25 30 35 40 533 824 8 if a trailer is connected and in which state of movement this in that case ends. The first and second sensor signals, which are generated by the braking device according to the invention on the drawbar trailer, are suitable for supply to a corresponding braking system on the towing vehicle, so that they can be taken into account during braking. On the other hand, the EBS modulator of the drawbar trailer can also be supplied with information about the movement condition of the towing vehicle. In this way, braking can be carried out in such a way that they take into account not only the state of movement of the towing vehicle but also of the towed tow truck, which contributes to increasing traffic safety. A possible function here would be that controlled braking is performed even without brake signals being supplied by the driver in order to counteract unstable movement conditions already in the initial stage.
    The invention also relates to a method for braking a drawbar trailer having two or two axles, more particularly to a method for braking a drawbar trailer with a front axle and one or two additional axles, the method having the following steps: by means of first sensor means axial first sensor signals relating to at least one of the input axes, which relate to the axle load of the axis sensed by the respective sensor means, are generated - by means of other sensor means axial second sensor signals are generated, for the wheels on the axle sensed by the respective sensor means, - brake signals formed in a towing vehicle are transmitted between the towing vehicle and the drawbar trailer by means of a transfer unit, the first and second sensor signals are received by me d by means of a control unit, - the axle load is determined by means of the control unit, - the magnitude of the brake pressure for the actuating rig of the brake means is determined by means of the control unit as a function of the determined axle load and the received brake signals, - means for adjusting the working pressure by the control unit, i - the magnitude of the working pressure is adapted to the brake pressure by means of the means, - the brake pressure is supplied to the brake means by means of lines and - the drawbar trailer is braked by means of the brake means, whereby the brake means can be operated with the brake pressure.
    The advantages obtained with the specified method according to the invention are the same as discussed in connection with the device according to the invention.
    A preferred embodiment of the method according to the invention is characterized in that the control unit determines the shaft load on the front shaft by means of the first sensor signals and the shaft load on the further shafts by means of the difference in slip between the first and the further shafts. . With this measure, it is sufficient to use a first sensor means only for the front axle. The other sensor means are widely used in modern towing vehicles, whereby the slip difference between the front axle and the additional axles can be easily determined.
    A preferred embodiment of the method consists in that the control unit determines the magnitude of the brake pressure by means of the average value of the determined axle loads. Calculating an average is a relatively simple mathematical operation, which does not require any complicated algorithms. This calculation can therefore be easily achieved with the help of the control unit and does not place high demands on the calculation capacity.
    A further embodiment of the method according to the invention is characterized in that the control unit determines the brake pressure on the basis of the highest available axle load. Since the axle with the highest axle load is also the axle that has the best grip, this embodiment ensures that the EBS modulator always determines the highest possible braking pressure and thereby can also take into account situations where the additional axles are significantly harder loaded than the front axle. . This can be achieved by arranging one or more of your pressure-sensitive components, for example bellows or pistons, which produce a rising pressure with increasing load, on each shaft. These components are connected to a pressure sensor via a select-high valve. As a result, the highest pressure is always applied to the pressure sensor, with which the currently highest load can be determined.
    A preferred embodiment of the method according to the invention consists in that the control unit selects the brake pressure by means of curve line folding as a function of at least one of the signals in a group consisting of the first and second sensor signals and the brake signals. With the help of the curve line, the switching functions are provided, which connect an input signal with an output signal. The input signal is primarily used as the brake signal, which is to be connected to an output signal in the form of a brake pressure. Other variables can also be used. Possible examples are frequent variations in the axle loads (first sensor signals) or large differences in the rotational speeds of the wheels (second sensor signals), which indicates unstable conditions for the drawbar trailer and makes it suitable to brake.
    The curve fields can have your sections. If the brake signal provided by the driver is used as an input signal, a first section, which corresponds to a low need for braking force, can be connected to an output signal in the form of a constant brake pressure. This provides even maneuvering of the brakes, which in turn gives an even load and even wear on the brake pads, so that these can be replaced less often. In the section for high-speed braking requirements, the curves connect the brake signals with a higher brake pressure, which enables maximum utilization of the available traction. The curve fold is formed by a host of coupling functions, whereby a certain type of towing vehicle, a certain axle load range or a certain slip difference can be represented by a certain coupling function. The applicable coupling function is selected from the curve field with an input unit, if the selection is made on the basis of the towing vehicle or by means of the first and second sensor signals, if the selection is made by means of the axle load interval or the slip difference. It is often sufficient that the switching functions have the form of linear functions. Thereby the values of the input signals 10 15 20 25 30 35 40 533 824 10 with a few calculation steps are connected with the corresponding values of the output signals.
    The control unit then only needs a small pressure storage space and many calculation steps can be performed in a short time. The determined braking pressure can then be adapted with only a small time delay to the rapidly varying driving conditions for the vehicle or to the required braking force for the vehicle.
    The invention will now be explained in more detail with reference to examples shown in the drawing. In this case, fi g 1 shows a preferred embodiment of a drawbar trailer with a braking device according to the invention.
    The drawbar trailer shown has a front axle 18 and a further axle 20. The front axle 18 can be controlled via a drawbar 26, with which it is connected to a towing vehicle (not shown). The front axle is provided with wheels 10 and the further axle 20 with wheels 14.
    The brake device according to the invention for the drawbar trailer further has brake means 30, which comprise brake cylinders 22, 24, an operating rod 28 and wheel brakes (not shown).
    The brake cylinders 22 then belong to the front axle 18 and the brake cylinders 24 to the further axle 20. The drawbar trailer further has an EBS modulator 6, which can be connected to a pressure accumulator 4 for compressed air. The EBS modulator comprises a control unit 42 and means 44 for adapting the working pressure to the determined brake pressure. The pressure accumulator 4 can be filled with pressure air from the towing vehicle through brake lines 1 and a trailing brake valve 3 “or by means of an external pressure source and provides a compressed air working pressure.
    The slip brake valve 3 comprises a non-return valve (not shown) with which the working pressure is secured.
    Furthermore, a device (not shown) for automatic braking of the drawbar trailer in the event of a break in the brake line 1 may also be included. , relating to the driving conditions of the towing vehicle, can be transferred from the towing vehicle to the EBS modulator and vice versa. The information can be transmitted through the brake line 16 or by wireless means. Furthermore, the drawbar trailer has first sensor means 12, which in the embodiment shown are designed as pressure sensors and as an air bellows and are arranged on the front axle 18. The first sensor means 12 form first sensor signals, which represent the axle load on the front axle 18. All four wheels 10, 14 are provided with second sensor means 32, which comprises an ABS sensor 9 and a pole wheel 11. The second sensor means 32 form second sensor signals, which represent the rotational speeds of the wheels 10, 14. The first and the second sensor signals are supplied through transmission lines 34, 36 to the EBS modulator. 6. The means 44 for adjusting the working pressure to the determined braking pressure can be provided with a pressure control channel.
    The means are connected to the brake cylinders 22, 24 by means of pressure lines 38, so that these can be operated by means of the brake pressure. The part of the pressure line 38 located between the EBS modulator 6 and the brake cylinders 24 belonging to the wheels of the further shaft 20 contains a 3/2-way valve 7 and an ABS modulator 8.
    In case of unbraked travel with the trailer, ie. when no brake signal is transmitted from the towing vehicle to the EBS modulator 6, the first sensor means 12 form the first sensor signals, which represent the static axle load on the front axle 18. The second sensor means 32 form the second sensor signals, which represents the rotational speeds of the wheels 10, 14 on the drawbar trailer. The first and the second sensor signals are applied to the EBS modulator 6, which from the first sensor signals calculates the static axle load of the front axle 18.
    If the EBS modulator 6 now receives a brake signal from the towing vehicle, the measured axle load no longer corresponds to the static axle load, but to the instantaneous axle load.
    The difference between the two loads is the dynamic axle load. The additional axle 20 is relieved due to the braking with the value of the dynamic axle load. If the static load on the further shaft is known, the instantaneous shaft load on the further shaft can be estimated on the basis of the calculated dynamic shaft load, without the need for a further first sensor means. The static axle load can be determined on the basis of the geometric properties of the drawbar trailer, which, however, gives a relatively imprecise result. Furthermore, changes in the axle load caused by the loading can not be taken into account at all or only with difficulty, in the first case especially if the distribution of the axle load changes due to displacement of objects in the load during travel. Furthermore, it is possible to determine the axle load in this way only if the trailer has a single additional axle 20 and not ytterligare your additional axles 20. _ _ The distribution of the axle loads determined at each time serves as a measure of how the braking force or brake pressure is to be distributed . A axle with a larger load has a stronger traction between the braked wheel and the road surface, whereby this axle can also be supplied with a higher braking force.
    In the example shown, the EBS modulator 6 uses the first and second sensor signals to determine a brake pressure that can be applied to the fi-shaft 18 without the wheels locking. If the brake pressure is still too high and the wheels lock, the EBS modulator is notified that the locked wheels are stationary from the other sensor means 32 via the other sensor signals and the transmission lines, after which the EB1S modulator regulates the brake pressure until the wheels no longer lock.
    In this case, the situation may arise that, for example, the left front wheel 101 locks earlier than the right front wheel 1011. This may be due to the right front wheel 1011 being more heavily loaded, for example due to an uneven distribution of the load. Furthermore, the ik- ict value of the road surface may differ if there is an oil stripe on the part of the road surface used by the left front wheel 101 ,. In this case, the EBS modulator 6 would regulate the brake pressure by means of the brake cylinder 221 until the left front wheel 101 no longer locks. However, the brake cylinder 2211 will continue to brake with the specified brake pressure. For this purpose, the EBS modulator 6 has two outputs, whereby brake cylinder drama 221 and 2211 can be applied to different brake pressures and the front wheels 101 and 1011 can be braked in a controlled manner, ie. so that the wheel 1011 in the present case is braked with the reduced braking pressure and the wheel 1011 with the determined braking pressure. In order that the determined brake pressure can nevertheless be supplied to the brake cylinders of the further shaft 20, the 3/2-way valve 7 is arranged. This is connected to both outputs of the EBS modulator 6 and produces a select high function, i.e. supplies the higher of the pressures emitted at both outputs of the EBS modulator to the brake cylinders 24. According to an alternative embodiment (not shown), the 3/2-way valve 7 can be omitted. In this case, the EBS modulator has a single output. Furthermore, the front wheels 10L and 10 ,, are connected via an ABS valve. If then one of the front wheels 10 locks, the brake pressure is regulated down until the reading stops. However, since the EBS modulator has only one output, the lower brake pressure is also applied to the second front wheel, which has not locked.
    Thus, a select-low regulation occurs. The resulting lower pressure is also applied to the additional shaft brake cylinders.
    In the embodiment shown, which includes the 3/2-way valve 7, the brake pressure determined by the EBS modulator is supplied not only to the brake cylinders 22 on the front axle 18, but also to the brake cylinders on the further axle 20. Thus, the brake pressure may be the wheels 14 on the additional axle 20 to lock. This is a typical situation in that braking when driving forward leads to an increase in the axle load on the front axle 18 and that the load on the further axle 20 decreases correspondingly, whereby the wheels 14 on the additional axle 20 lock even at a lower braking pressure. .
    In general, however, locking of the wheels must be prevented, as otherwise the drawbar trailer will be in an unstable state of movement. In order that the wheels 14 on the further shaft 20 do not lock, the ABS modulator 8 is arranged in the part of the compressed air line which is located between the EBS modulator 6 and the brake cylinders 24 of the further shaft 20. The ABS modulator 8 essentially acts as a pressure reduction. which can lower the brake pressure as a function of the rotational speed of the wheels. Thus, if the second sensor means 32 belonging to the further axle finds that the wheels 14 are locking, the ABS modulator 8 lowers the braking pressure until the reading of these wheels ceases. For this purpose, the EBS modulator 6 is connected to a solenoid valve (not shown) in the ABS modulator 8 through a control line 40, whereby the EBS modulator 6 emanating from the other sensor signals can lower the brake pressure until none of the wheels 14 locks anymore. In the embodiment shown, the brake pressure can only be changed for each high axle, whereby the brake cylinders for the wheels on each individual axle can always be supplied with the same brake pressure. This is based on experience that the wheel loads for the wheels on one axle vary considerably less than the wheel loads for the wheels on different axles. Despite this, situations may arise where the ABS modulator 8 lowers the brake pressure due to one of the wheels locking even though the other wheel or the other wheels on the same axle could be braked with a higher braking distance. This can occur if the wheels on a axle are very differently worn or if the road surface has very different friction numbers, for example due to a locally limited oil eller eck or a pool of water, which only affects one wheel or a group of wheels on one axle. Even if in such a case it is not possible to apply the maximum braking force, this is still acceptable or even advantageous. If a wheel on one side were braked much harder than the wheel on the other side of the same axle, a strong turning moment would occur, ie. the vehicle would rotate about a vertical axis, which would lead to an unstable condition of the vehicle.
    In the event that the further axle 20 has a significantly higher axle load than the front axle 18, for example due to a heavy load located above the further axle 20 caused by unevenly distributed load, the braking pressure applied by the EBS modulator 6 leads to the wheels on the front axle 18 just avoids locking. However, due to the high axle load, the wheels 14 on the further axle 20 could be braked with a significantly higher braking force, which, however, is not possible with the braking pressure applied by the EBS modulator 6. Consequently, the drawbar trailer would not be braked with the maximum possible braking force,, ie. braking, which is not desirable when it comes to minimizing braking distance. In view of this case, it is possible to provide a pressure circuit (not shown) with an additional valve, which makes it possible to direct the full working pressure supplied by the pressure accumulator 4 to the brake cylinders of the further shaft 20. In this case, the auxiliary valve is operated in an appropriate manner by the EBS modulator. Actually, the wheels 14 on the additional axle 20 can be braked with the highest possible brake crane. If the working pressure applied by the pressure accumulator 4 should lead to the wheels 14 locking, the ABS modulator 8 lowers the working pressure in the manner described above. After restoring the condition at which the braking pressure determined by the EBS modulator 6 is sufficient to lock the wheels 14 belonging to the further shaft 20, the auxiliary valve is set in such a position that it is again the braking pressure and not the working pressure from the compressed air source supplied.
    The invention has been described on the basis of an exemplary embodiment, but it is obvious to the person skilled in the art that it can be varied in many ways within the scope of the basic idea.
    权利要求:
    Claims (13)
    [1]
    Brake device for braking a drawbar trailer with a front axle (18) and one or more additional axles (20), each axle having at least two wheels, with - first sensor means (12) for forming axial axes for at least one of the included axles first sensor signals relating to the axle load of the axle sensed by the respective sensor means, - second sensor means (32) for forming at least one of the input axes axial second sensor signals relating to the rotational speed of the wheels on the one of the the shaft means sensing the shaft, - a pressure accumulator (4) for supplying and storing a pneumatic working pressure, - brake means (30) for braking the drawbar trailer, the brake means (30) being operable with a pneumatic brake pressure, - a brake line (1) and / or a transmission unit (16) for transmitting brake signals generated in the towing vehicle between the towing vehicle and the drawbar trailer, - a control unit (42) for receiving the transmission units above the and of the first and second sensor signals and to determine the axle load and - means (44) for adjusting the magnitude of the working pressure to the brake pressure, whereby the brake pressure can be supplied to the brake means (30) by means and the means (44) can be activated by the control unit (42 ), characterized in that - the control unit (42) determines the magnitude of the brake pressure for the operation of the brake means (30) as a function of the determined axle load on the front axle (18) and on the one or ytterligare further axles (20) as well as of the received brake signals and activating the means (44) in such a way that the determined brake pressure is applied with the same magnitude to the brake means (30) on the fi axis (18) and to the brake means (30) on the one or fl further axles (20). .
    [2]
    2.2. Braking device according to the sea 1, characterized in that one of the first sensor means (12) is arranged for the front axle (18).
    [3]
    Braking device according to Claim 1 or 2, characterized in that the first sensor means (12) are designed as pressure sensors or wall sensors.
    [4]
    Braking device according to one of the preceding claims, characterized in that the second sensor means (32) comprise a pole wheel (9) and an ABS sensor (11).
    [5]
    Braking device according to one of the preceding claims, characterized in that the maximum size of the determined braking pressure is determined by the maximum traction of the wheels on the front axle (18).
    [6]
    Braking device according to one of the preceding claims, characterized in that the braking means (30) comprise brake cylinders (22, 24) and wheel brakes arranged at the wheels.
    [7]
    Brake device according to one of the preceding claims, characterized in: in that the means (44) for adjusting the working pressure to the brake pressure are connected to the control unit (42) to an EBS modulator (6).
    [8]
    Braking device according to Claim 7, characterized in that the EBS modulator (6) can be supplied with information by means of the transmission unit (16) by means of the transfer unit (16) and / or that the towing vehicle can be supplied by means of the transfer unit (16). the first and second sensor signals.
    [9]
    Method for braking a drawbar trailer with a front axle (8) and one or more additional axles, with the following steps: - by means of first sensor means (12) axial first sensor signals are generated for at least one of the included axles, which relate to the axle load of the shaft sensed by the respective sensor means, ~ by means of second sensor means (32) are generated for at least one of the input axes axial second sensor signals, which relate to the rotational speed of the wheels on the shaft sensed by the respective sensor means, traction signals formed by towing vehicle are transmitted between the towing vehicle and the drawbar trailer by means of a brake line (1) and / or a transfer unit (16), - a compressed air working pressure is provided and stored by means of a compressed air accumulator (4), - that of the brake line (1 ) and / or the transmission unit (16) transmitted the information and the brake signals as well as the first and second sensor signals are received by means of a control unit (42), - a the axle load is determined by means of the control unit (42), - the magnitude of the brake pressure for the operation of the brake means (30) is determined by means of the control unit (42) as a function of the determined axle load and the received brake signals, I - means (44) for adjustment of the size of the working pressure to the brake piece is activated by means of the control unit (42), - the size of the working pressure is adapted to the brake pressure by means of the means (44), - the brake piece is supplied with the same size to the brake means (30) by means of leads (38) and - by means of the brake means (30), the brake means (30) being operable with the brake pressure.
    [10]
    Method according to claim 9, characterized in that the control unit determines the axle load on the front axle (18) by means of the first sensor signals and the axle load on the further axles (20) by means of the difference in displacement between the front axle (18) and the further axles. (20), the difference in slip being calculated using the other sensor signals.
    [11]
    Method according to Claim 9 or 10, characterized in that the control unit (42) determines the magnitude of the brake pressure on the basis of the average value of the determined axle loads.
    [12]
    Method according to claim 9, characterized in that the control unit (42) determines the brake pressure on the basis of the highest prevailing axle load.
    [13]
    Method according to one of Claims 9 to 12, characterized in that the control unit (42) selects the brake pressure on the basis of curved roller lines as a function of at least one of the signals in a group consisting of the first and second sensor signals and the brake signals.
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    同族专利:
    公开号 | 公开日
    SE0900466L|2009-11-03|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2021-11-30| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    DE202008022026|2008-05-02|
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