VEHICLE CRANE WITH HYDROPNEUMATIC SUSPENSION AND A BRAKE SYSTEM COMPLETING AT LEAST TWO BRAKE CIRCUITS

Description

[0001] The invention relates to a mobile crane with hydropneumatic suspension and with a braking system comprising wheel brakes, which has a first braking circuit assigned to the wheel brakes of at least one vehicle axle of the mobile crane and at least one further braking circuit assigned to the wheel brakes of at least one further vehicle axle of the mobile crane.

[0002] In order for a mobile crane to be approved for use on public roads, it must meet the country-specific requirements of the respective country. This usually requires a type approval, a general operating permit, or an individual operating permit obtained individually by means of an expert opinion. This applies not only to motor vehicles designed for the transport of people and / or goods, but also to special vehicles such as mobile cranes, whose various locations are known to be reached mostly via the public road network. As autonomously driven vehicles, their wheeled chassis require a suitable braking system and suitable suspension. UN regulations, applicable throughout the European Union and beyond, stipulate the requirements to be met; for example, ECE R 13 contains the regulations for braking systems.

[0003] Conventional suspension systems usually rely on mechanical springs whose vibrations are dampened by telescopic shock absorbers. In contrast, hydropneumatic suspension systems combine the functions of springs and dampers in hydraulically and pneumatically operated damper units. These have a hydraulic cylinder that is integrated, for example, between a frame and a relatively movable vehicle axle or a relatively movable wheel of a mobile crane. The oil-filled hydraulic cylinders are each fluidly connected to a pressure vessel that serves as an accumulator. The accumulator is divided into two chambers by a diaphragm, with the chamber facing the hydraulic cylinder filled with oil and the remaining chamber filled with gas. Due to its compressibility, the gas acts as a suspension element, while the oil, which is displaced during the spring process, serves as the damping element.In contrast to the level that decreases with increasing weight in mechanically sprung vehicles (load-dependent ground clearance), hydropneumatic suspension systems allow a load-independent level by changing the oil volume in the accumulator of the respective damper unit.

[0004] German utility model DE 20 2007 004 091 U1 discloses a mobile crane featuring such a hydropneumatic suspension. The hydropneumatic suspension is primarily active when the mobile crane is being moved on public roads. In stationary use, its spring properties can be locked, while the leveling of the mobile crane, which is still possible, for example, on each axle, also enables its safe installation on sloping ground. Furthermore, the mobile crane features a braking system whose regulatory design requires the arrangement of two independent brake circuits.

[0005] In order to comply with the construction and operating regulations stipulated in the German Road Traffic Licensing Regulations, vehicles must be equipped with a braking system with prescribed deceleration values. Particularly for large and therefore heavy special vehicles, such as mobile cranes, the design of the braking system must meet correspondingly high requirements. Moving vehicles on public roads requires compliance with a maximum axle load; in particular, driving over bridges is limited to a maximum vehicle weight. If the actual axle load or the permissible vehicle weight exceeds the respective permissible values, these must be reduced accordingly. To comply with official regulations, mobile cranes, for example, must sometimes be designed so that at least one of their components is removable.The significantly influenced total weight of the remaining vehicle in road traffic has a correspondingly strong impact on its braking performance and, thus, on the question of how to correctly control the braking system in order to meet regulatory requirements. The same applies to other vehicles whose load conditions are subject to corresponding fluctuations, for example, due to the loading or unloading of goods to be transported. Especially in light of the approval issue regarding their braking systems, the vehicles of this type known to date still offer room for improvement.

[0006] Furthermore, published patent application DE 26 22 534 A1 discloses a load-dependent hydraulic four-circuit braking system for a commercial vehicle with a hydropneumatic suspension. Each spring strut of the hydropneumatic suspension is assigned a brake pressure regulating valve. A pressure increase in the spring strut is used to increase the pressure in the associated brake cylinder via the brake pressure regulating valve. A hydraulic pump provides the unaffected brake pressure. The hydropneumatic suspension and the hydraulic brake are thus fluidly connected via the brake pressure regulating valve. To increase the pressure, oil flows from the hydropneumatic suspension into the hydraulic braking system.

[0007] Furthermore, Japanese Patent Application JP S60 25810 A describes a vehicle with hydropneumatic suspension. Typically, the hydropneumatic suspension provides a hydraulic suspension cylinder and a pressure accumulator for each wheel of the vehicle. To improve suspension comfort and minimize lateral roll of the vehicle, the suspension constant of the pressure accumulator can be adjusted by changing its air volume. For this purpose, a load sensor is arranged for each wheel in the area of ​​the hydraulic suspension cylinders, the signal from which is evaluated to determine the change in its air volume.

[0008] Also known from patent US 4,986,609 A is a passenger car with a hydraulic braking system with two brake circuits. The hydraulic braking system includes a proportioning valve system for adjusting the brake pressure of the front and rear wheel brakes depending on the load on the rear wheels. For this purpose, the proportioning valve system is connected to a load sensor, which can measure the load on the rear wheels.

[0009] The invention is based on the object of further developing a mobile crane equipped with a hydropneumatic suspension in such a way that the control of its braking system can be adapted, preferably continuously, to the respective weight condition of the mobile crane.

[0010] The solution to this problem according to the invention consists in a mobile crane having the features of claim 1. Advantageous embodiments of the invention are specified in the respective dependent claims 2 to 14.

[0011] According to this, the mobile crane according to the invention comprises at least one automatic load-dependent brake force regulator (ALB), which is coupled to the hydropneumatic suspension of the mobile crane. The automatic load-dependent brake force regulator is operatively connected, at least in part, to one of the brake circuits of the braking system. "In part" here means that the automatic load-dependent brake force regulator can be operatively connected either to an entire brake circuit or only to one section, i.e., to at least one brake circuit section of a brake circuit.The automatic load-dependent brake force regulator and the brake circuit or brake circuit section are operatively connected to one another in such a way that, based on a weight status signal of the mobile crane generated from the hydropneumatic suspension, a brake pressure that can be generated within the brake circuit or brake circuit section coupled to the automatic load-dependent brake force regulator can be varied relative to a brake pressure that can be generated simultaneously within the other brake circuit or brake circuit section. Accordingly, it is now possible for said brake pressures in parts of the braking system to have different values ​​due to a change in the total weight of the mobile crane.In other words, the automatic load-dependent brake force regulator ensures that the brake pressure that can be generated in the brake circuit or brake circuit section that is at least partially coupled to the automatic load-dependent brake force regulator - and thus controllable - can be varied depending on the respective weight of the mobile crane from the brake pressure that can be generated simultaneously in the other brake circuit or brake circuit section. Because the brake pressures in parts of the braking system, which previously remained constant when the total weight of the mobile crane changed, can now be regulated, advantageously adapting to the driving dynamic forces directly resulting from the change in weight is possible. It should be noted that the operating pressure of the braking system is usually adjusted to the maximum permissible total weight of the mobile crane and that the available pneumatic brake pressure cannot be increased.The automatic load-dependent brake force regulator used according to the invention thus successfully prevents overbraking of the mobile crane, should the vehicle have a lower vehicle weight due to the disassembly of crane parts. The invention also provides that the brake pressure that can be generated within the brake circuit or brake circuit section coupled to the automatic load-dependent brake force regulator, in particular acting on the associated wheels, corresponds to the brake pressure that can be generated simultaneously within the other brake circuit and / or brake circuit section without any change by the automatic load-dependent brake force regulator.In this context, it is intended that the brake pressure that can be generated within the brake circuit or brake circuit section coupled to the automatic load-dependent brake force regulator can then be regulated by the automatic load-dependent brake force regulator relative to the value of the brake pressure that can be generated simultaneously within the other brake circuit and / or brake circuit section. "Regulatable" here means that the respective brake pressure can be reduced accordingly by the automatic load-dependent brake force regulator. The resulting advantage is the now possible, extremely advantageous adjustment of the brake force distribution within the individual brake circuits or brake circuit sections of the braking system depending on a changing vehicle crane weight.Since this adjustment occurs without conscious intervention by a person operating the mobile crane, the braking force is always distributed to the wheel brakes of the braking system in an appropriate manner, depending on the respective weight of the mobile crane. Without such braking force distribution, for example, the rear or front axle(s), or at least one of them, would be actuated with the same pressure as the other axle(s) during partial braking, even in a reduced-weight state, e.g., due to the dismantling of a component of the mobile crane. This could cause the rear and / or front wheels to lock, causing the mobile crane to skid uncontrollably. The same applies to a mobile crane with more than two vehicle axles, where two or more vehicle axles each belong to one of the brake circuits or brake circuit sections.The load-dependent brake force control according to the invention ensures, for example, a reduction in the brake pressure in the wheel brakes on at least one vehicle axle, depending on the respective weight condition of the mobile crane. Conversely, the brake pressure on at least one vehicle axle can exceed the brake pressure on at least one other vehicle axle under certain weight conditions.

[0012] According to a preferred development of the basic inventive concept, a control input can be arranged on the automatic load-dependent brake force regulator. "Arranged" means that the control input can, for example, be a one-piece component of the automatic load-dependent brake force regulator, in particular its housing, or can be connected to it as a separate component. In any case, the control input is designed and arranged such that it enables a fluid-conducting connection to the automatic load-dependent brake force regulator in the sense of a connection. The control input is fluid-conductingly coupled to the hydropneumatic suspension of the mobile crane in such a way that its respective pressure can be used as the weight status signal used to control the automatic load-dependent brake force regulator.In this way, the respective pressure of the hydropneumatic suspension can advantageously represent a direct control variable for the distribution of the brake pressure within the brake circuits or brake circuit sections of the brake system.

[0013] In this case, it is preferably provided that at least one suspension circuit of the hydropneumatic suspension is assigned to the control input, and that this at least one suspension circuit is also assigned to at least some of the vehicle axles that are assigned to the respective automatic load-dependent brake force regulator, i.e., the associated brake circuit or brake circuit section. In this context, it is further preferred that the at least one suspension circuit is assigned precisely to the vehicle axles that are assigned to the respective automatic load-dependent brake force regulator, i.e., the associated brake circuit or brake circuit section.

[0014] In the specific application, a quasi-real-time, for example proportional, change in the distribution of the respective brake pressure to the brake circuits or brake circuit sections can be made on the basis of the respective weight condition of the mobile crane, in order to effectively prevent ineffective overbraking of the wheel brakes of one or more vehicle axles connected to a brake circuit or brake circuit section.

[0015] In principle, the basic setting of the braking system can already be such that the same braking pressure is applied in all brake circuits or brake circuit sections, but that different braking forces are available in the wheel brakes of the front, middle and rear axles, depending on the mobile crane and its weight distribution. For this purpose, the wheel brakes then have a design and / or number that provides an advantageous distribution of braking force with regard to the respective braking performance, particularly with the maximum total weight of the mobile crane or the maximum permissible axle loads. This can be achieved, for example, through the number of respective brake calipers and / or the size of their brake cylinders. The corresponding reduction in the weight of the mobile crane when at least one component is dismantled can then be used as an opportunity to reduce the effective pressure in one of the brake circuits and / or one of the brake circuit sections.The structural design otherwise intended for the maximum vehicle crane weight remains unaffected, so that the braking force is adjusted via the automatic load-dependent braking force controller.

[0016] By appropriately designing the braking system, it is also possible to take into account the natural circumstance that when a mobile crane decelerates, its weight increasingly acts on the front wheels, while the rear wheels simultaneously experience relief from the load being transferred to the ground via these wheels. For this reason, the deceleration effectiveness of the front wheels is generally greater than that of the rear wheels, since the latter lock up more quickly due to the relief and thus can contribute little to the actual deceleration of the mobile crane.

[0017] Alternatively, a basic setting of the braking system can be provided in which the braking pressures in the braking circuits or braking circuit sections differ from one another in order to achieve an advantageous distribution of the braking forces to the individual wheel brakes, in particular with the maximum total weight of the mobile crane or the maximum permissible axle loads.

[0018] Within the scope of the invention, it is considered particularly advantageous if the automatic load-dependent brake force regulator is connected to the hydropneumatic suspension on the control side and has a control range of up to a maximum of 160 bar, preferably 200 bar. The aforementioned control range is tailored to a mobile crane in road operation. This high pressure design of the automatic load-dependent brake force regulator itself, which is unusual compared to conventional automatic load-dependent brake force regulators, is advantageous because suspension systems used in mobile cranes in particular operate at significantly higher operating pressures than those used in other passenger vehicles or trucks, for example. This is necessary due to the very high weight of the mobile crane in order to be able to control the appropriately designed damper units of the hydropneumatic suspension according to requirements.Compared to the use of possible pressure intensifiers in conjunction with the use of an automatic load-dependent brake force regulator designed for lower pressures, this results in a more compact design with fewer parts.

[0019] For the design of the automatic load-dependent brake force regulator outside or above its control range, a maximum pressure of 250 bar, preferably a maximum of 300 bar, and in particular a maximum of 350 bar could be specified as the possible pressure load from the hydropneumatic suspension. This pressure resistance enables a mobile crane to be operated in crane mode even outside of road operation, and thus when moving in a rigged state and / or under load. Alternatively, instead of designing the entire automatic load-dependent brake force regulator to be pressure-resistant, a protective valve with appropriate pressure resistance can be installed upstream of it, which blocks at pressures above 160 bar or 200 bar.

[0020] According to a preferred further development of the mobile crane according to the invention, the brake circuit or brake circuit section operatively connected to the automatic load-dependent brake force regulator can be assigned to one or more vehicle axles. Furthermore, the other brake circuit or brake circuit section can be assigned to at least one, preferably two or more, further vehicle axle(s). Particularly in the case of a multi-axle mobile crane, this allows optimal control of the individual vehicle axles with regard to the braking performance at the individual wheels, with regard to its design and / or structural weight distribution. In a corresponding manner, one or more brake circuits or brake circuit sections can each be assigned an automatic load-dependent brake force regulator. The number and arrangement of the brake circuits or brake circuit sections depends on the type of mobile crane, its number of axles, and its weight distribution.Depending on the mobile crane, at least one automatic load-dependent brake force regulator can be assigned to each brake circuit or brake circuit section, regardless of whether it is assigned to the front, middle, or rear axles of the mobile crane. A guideline for the number and assignment of automatic load-dependent brake force regulators to the brake circuits can be a preliminary analysis of the impact of a possible reduction in the mobile crane's weight on the respective axle load, for example, by dismantling a telescopic boom for road travel.

[0021] In this context, the mobile crane according to the invention can, for example, have two to a total of, for example, ten individual vehicle axles. The brake circuit or brake circuit section operatively connected to the automatic load-dependent brake force regulator can be assigned to one or more vehicle axles, while the other brake circuit and / or brake circuit section is assigned to the remaining vehicle axles. Due to the number and targeted allocation of the vehicle axles to the brake circuits and / or brake circuit sections, a highly advantageous control of the wheel brakes of the braking system results with regard to the different distribution of the brake pressure across these brake circuits and / or brake circuit sections.

[0022] In principle, the automatic load-dependent brake force regulator can preferably be operatively connected to at least one brake circuit or brake circuit section whose at least one axle of the mobile crane braked by this circuit exhibits the greatest negative effects when the mobile crane's weight is reduced. This circumstance is individual and depends on the specific design of the mobile crane and, in particular, the position of the at least one assembly intended for disassembly.

[0023] Particularly preferably, the hydropneumatic suspension of the mobile crane according to the invention can have a level control. For example, by changing the volume of the oil in the associated suspension circuit, the immersion depth of a piston in the hydraulic cylinder can be influenced, which enables a change in the height of the suspension system and thus a change in the level of the mobile crane. Such a level control enables adaptation to the respective surface, preferably on a wheel-by-wheel basis, in particular on an axle-by-axle basis. This applies to the mobile crane when in motion and / or at a standstill.

[0024] According to an advantageous development, the hydropneumatic suspension of the mobile crane according to the invention can have an axle load compensation within one of its suspension circuits. Said axle load compensation can be effective at least between steered and / or unsteered vehicle axles to compensate for their axle loads. Such axle load compensation improves ride comfort and traction due to the weight distribution thus possible between two or more vehicle axles, particularly off-road. Furthermore, this also allows a further improvement with regard to overbraking of one or more vehicle axles. The resulting reduction in dynamic axle load fluctuations also advantageously reduces the load on the respective surface over which the mobile crane is traveling, in particular the road.Overall, the axle load compensation allows for the greatest possible compensation for any longitudinal undulations in the surface to be driven on.

[0025] The invention provides that the mobile crane can also have two or more automatic load-dependent brake force regulators. In this case, each of these automatic load-dependent brake force regulators is coupled to one of the brake circuits or brake circuit sections. By using more than one automatic load-dependent brake force regulator, an improved adjustment of the respective brake pressures can be achieved. This is particularly important against the background of a weight distribution of the remaining total weight, which can sometimes change significantly when one or more components of the mobile crane are dismantled. For example, only the front or rear brake circuit or a corresponding brake circuit section thereof can be coupled to an automatic load-dependent brake force regulator. Alternatively, both brake circuits or corresponding brake circuit sections thereof can be coupled to an automatic load-dependent brake force regulator.The arrangement of one or more automatic load-dependent brake force regulators also applies if the mobile crane has more than two brake circuits in relation to its service brake.

[0026] In the context of the arrangement of two or more automatic load-dependent brake force regulators, these can be set identically or differently from one another. This is particularly true with regard to their control and / or response behavior. In this way, the requirements for such a brake pressure control system resulting from the specific design of the mobile crane can be advantageously met. For example, the respective weight distribution with respect to the mobile crane can sometimes differ from one another after disassembly of at least one of its components, depending on the design. This can be taken into account through targeted arrangement, adjustment, and integration into the braking system in order to achieve the best possible results in terms of braking behavior.

[0027] The mobile crane according to the invention now presented enables the extremely simple and effective adaptability of the control of its braking system to its respective weight condition. By incorporating at least one appropriately designed, automatic, load-dependent brake force regulator between one of the brake circuits to be controlled, or one of their brake circuit sections to be controlled, and the hydropneumatic suspension, said adaptability is automated and preferably continuously implementable, which always enables optimal distribution of the brake pressure within the individual brake circuits and / or their brake circuit sections and the associated vehicle axles or wheel brakes. Imbalances in the brake force distribution, which would otherwise quickly arise in the event of a change in weight condition, and the associated overbraking of at least one individual vehicle axle, are virtually eliminated by the inventive design.Compared to the manual adjustments sometimes required to adjust the brake force distribution, the mobile crane according to the invention allows for automated and therefore safer adjustment. This virtually eliminates the potential for incorrect operation during manual adjustment, with its associated consequences.

[0028] Preferably, the braking system is pneumatic.

[0029] The present invention is particularly suitable for mobile cranes that have at least three vehicle axles.

[0030] Furthermore, it is preferably provided that the number of brake circuits or brake circuit sections is greater than the number of automatic load-dependent brake force regulators. In other words, no automatic load-dependent brake force regulator is assigned to a brake circuit or brake circuit section, and thus the full brake pressure is always present there.

[0031] An embodiment of the invention is explained in more detail with reference to the following description of the figures showing a mobile crane according to the invention with eight vehicle axles. They show: Figure 1 a schematic diagram of a braking system of a mobile crane according to the invention, Figure 2 the diagram according to Figure 1 with a first brake circuit highlighted by thick lines and Figure 3 the diagram according to Figure 1 with a second brake circuit highlighted by thick lines and divided into two brake circuit sections.

[0032] Figure 1shows a mobile crane 1 according to the invention, which comprises a wheeled chassis with a total of eight vehicle axles A1 - A8, shown here as an example, spaced parallel to one another. A vehicle cabin 2 indicates the front part of the mobile crane 1. Based on the illustration, it is clear that, for example, the vehicle axle A1 adjacent to the vehicle cabin 2 represents the foremost of the front vehicle axles A1 to A5, while of the other rear vehicle axles A6 to A8, the vehicle axle A8 located at the opposite end and thus furthest from the foremost vehicle axle A1 is the rearmost vehicle axle A8 of the mobile crane 1. Each of these eight vehicle axles A1 to A8 has two opposite wheels 3a, 3b rotatably mounted on them, and thus each has a right wheel 3a and an associated left wheel 3b.Each of these wheels 3a, 3b is assigned a corresponding right wheel brake 4a or a corresponding left wheel brake 4b to decelerate or even prevent their free rotation as needed. In the example shown here, the two front vehicle axles A1, A2 are each equipped with two wheel brakes 4a, 4b or brake calipers (double-caliper brakes) to achieve a structurally increased braking effect compared to the other vehicle axles A3 to A8, which is matched to the maximum permissible axle loads. In contrast, the other wheel brakes 4a, 4b in this case are single-caliper brakes.

[0033] The wheel brakes 4a, 4b are part of a pneumatic braking system 5, the individual components of which are fluidly connected to one another via a plurality of pneumatic lines L. These components include two pneumatic pumps 6a, 6b in the example shown here. These pumps are provided with an air dryer 7 and a protection valve 16 for filling air reservoirs 8, each equipped with a separator 9, with air. The air reservoirs 8 serve as pneumatic pressure accumulators to provide the pneumatic pressure required to operate the wheel brakes 4a, 4b. The braking system 5 primarily has two separate brake circuits K1, K2 (service brakes) in the sense of a dual-circuit braking system with two service brake circuits for the two structurally separate service brakes of the mobile crane 1. The wheel brakes 4a, 4b of a vehicle axle A1 to A8 are each assigned to one of these two brake circuits K1, K2.Said brake circuits K1, K2 comprise a rear brake circuit K1 and a front brake circuit K2. The front brake circuit K2 is divided into a first front brake circuit section K2.1 and a second front brake circuit section K2.2, as will be explained in particular below. Figure 3 explained in more detail. The brake circuits K1, K2 are coupled to a brake pedal 10 arranged in the vehicle cabin 2 and acting as a foot brake, so that all wheel brakes 4a, 4b can be activated accordingly by actuating it. Furthermore, a lever 11 is provided in the vehicle cabin 2, which serves to actuate a structurally third brake in the form of a parking brake. Its fluid connection to some of the wheel brakes 4a, 4b designed as spring-loaded brake cylinders is established via a third brake circuit K3 for a parking brake, separate from the two brake circuits K1, K2 of the service brakes. Another, in Figure 1The only indicated pressure circuit K4 serves to supply secondary consumers, which are not shown in detail.

[0034] Furthermore, the mobile crane 1 has a hydropneumatic suspension 12, which is not shown in detail but only symbolically for the sake of clarity. This hydropneumatic suspension enables the usual suspension and damping of the wheels 3a, 3b or vehicle axles A1 to A8, which are movable relative to the rest of the mobile crane, in a manner not shown in detail. Furthermore, this can preferably have a level control. The hydropneumatic suspension 12 is divided into several circuits. This means that their hydraulic cylinders (not shown in detail) are fluidly connected to one another such that they are each assigned to a suspension circuit 13a, 13b. Preferably, the hydropneumatic suspension 12 can have axle load compensation within at least one suspension circuit 13a, 13b. The suspension circuits 13a, 13b are usually divided between the right wheels 3a and the left wheels 3b.In addition, the suspension circuits 13a, 13b are also assigned to individual or multiple axles A1 to A8. The previously described mobile crane 1 has three brake circuits K1, K2.1, and K2.2, to which the axles A1 and A2; A3 and A4; and A5 to A8 are each assigned. Thus, a total of preferably six suspension circuits 13a, 13b are present, of which the associated right and left suspension circuits 13a, 13b are each assigned to one of the brake circuits K1, K2.1, and K2.2 and thus to the axles A1 and A2; A3 and A4; and A5 to A8. This achieves the best control results. More than one right and one left suspension circuit 13a, 13b can be provided for each brake circuit K1, K2.1, and K2.2. In this case, however, it is recommended to provide one or more automatic load-dependent brake force regulators 14 for each axle A1 to A8 and suspension circuits 13a, 13b. More than two suspension circuits 13a, 13b can also be used for each brake circuit K1, K2.1, and K2.2 can be connected to only one existing automatic load-dependent brake force controller 14. Their signals are then processed as an arithmetic mean. The brake is thus always controlled according to the current axle load. The suspension circuits and the brake circuits can also overlap. However, this should be avoided, as this also makes the control more complex.

[0035] Since the brakes of an axle A1 to A8 with right and left wheels 3a, 3b are generally assigned to two suspension circuits 13a, 13b each, the axle load results from these two suspension circuits 13a, 13b. Accordingly, the brake pressure is regulated according to the axle load via the automatic load-dependent brake force regulator 14. Random fluctuations in the wheel loads between the right and left wheels 3a, 3b do not lead to any change in the braking forces. Only when the axle load as a whole changes is the associated brake pressure also adjusted via the automatic load-dependent brake force regulator 14.

[0036] If full suspension pressure is present in the suspension circuits 13a, 13b of each brake circuit K1, K2.1, and K2.2, the associated automatic load-dependent brake force regulator 14 provides full brake pressure to the respective brake circuits K1, K2.1, and K2.2. Furthermore, the suspension circuits 13a, 13b and the brake circuits K1, K2.1, and K2.2 are fluidically separated, and there is no exchange of fluids between them.

[0037] According to the invention, the mobile crane 1 has one or more automatic load-dependent brake force regulators 14, which are integrated between the braking system 5 and the hydropneumatic suspension 12 in a manner described in more detail below. The hydropneumatic suspension 12 is connected on the control side to the automatic load-dependent brake force regulator(s) 14. The signals from the two suspension circuits 13a, 13b are processed by the automatic load-dependent brake force regulator 14 as an arithmetic mean. In the present example, a single automatic load-dependent brake force regulator 14 is shown. Due to the high suspension pressures required for a mobile crane 1, the automatic load-dependent brake force regulator(s) 14 are designed for a pressure application of at least 160 bar, preferably up to 200 bar, within their control range. The aforementioned control range is adapted to a mobile crane 1 in road operation.In order to be able to operate the mobile crane 1 in crane travel mode, and thus when traveling in the rigged state and / or under load, the automatic load-dependent brake force regulator is protected from higher pressures outside or above its control range. This can be achieved, on the one hand, by designing the automatic load-dependent brake force regulator for pressure from the hydropneumatic suspension up to a maximum of 250 bar, preferably a maximum of 300 bar, in particular a maximum of 350 bar, and, on the other hand, by installing a protective valve with appropriate pressure resistance upstream of the automatic load-dependent brake force regulator, which shuts off at pressures above 160 bar or 200 bar.

[0038] Figure 2 shows the already in Figure 1visible mobile crane 1, in which one of the two brake circuits K1, K2 is highlighted in the form of a rear brake circuit K1 - now by means of thick lines. It can be seen that the rear brake circuit K1 is fluidly connected via pneumatic lines L to the pneumatic pumps 6a, 6b, which are structurally separated in particular from those pneumatic lines L supplying the other brake circuit K2. This also applies to the integration of the brake pedal 10, which has two separate valves 10a, 10b for this purpose. The rear brake circuit K1 is connected to a first valve of the brake pedal 10, while the other, as the front brake circuit K2, is connected to a second valve of the brake pedal 10 (see also Figure 3). In this embodiment, the rear brake circuit K1 is assigned to the three rear vehicle axles A6 to A8. This means that when the brake pedal 10 is actuated, only the wheel brakes 4a, 4b arranged on the three rear vehicle axles A6 to A8 are actuated exclusively by the brake pressure then present within the rear brake circuit K1.

[0039] Figure 3 also shows the already in Figure 1 and also in Figure 2visible mobile crane 1, in which the front brake circuit K2 is now highlighted with thick lines. In order to clarify the section-by-section division of the front brake circuit K2 into the first and second front brake circuit sections K2.1, K2.2, the first front brake circuit section K2.1 is indicated by a continuous thick line, while the second front brake circuit section K2.2 is highlighted with a broken thick line. It can be seen that the first front brake circuit section K2.1 is assigned to the middle three vehicle axles A3 to A5. This means that when the brake pedal 10 is actuated, only the wheel brakes 4a, 4b arranged on these middle three vehicle axles A3 to A5 are actuated exclusively by the brake pressure then present within the section of the front brake circuit K2 - in the form of the first front brake circuit section K2.1 - i.e. section K2.2 is controlled with the same pressure as K1 but is influenced by the automatic load-dependent brake force regulator 14.

[0040] It can also be seen that the other section of the front brake circuit K2—in the form of the second front brake circuit section K2.2—is assigned to the two front vehicle axles A1, A2. This means that when the brake pedal 10 is actuated, only the wheel brakes 4a, 4b arranged on the two front vehicle axles A1, A2 are controlled exclusively by the brake pressure present within the second front brake circuit section K2.2, which contains the automatic load-dependent brake force regulator 14, and which can be regulated by this.

[0041] When the brake pedal 10 is actuated, the wheel brakes 4a, 4b of the eight vehicle axles A1 to A8, for example, are pneumatically actuated simultaneously via their respective brake circuits K1, K2. The wheel brakes 4a, 4b connected to the rear brake circuit K1 and the first front brake circuit section K2.1 (as a section of the front brake circuit K2) are actuated directly via the brake pedal. According to the invention, the automatic load-dependent brake force regulator 14 is operatively connected to the second front brake circuit section K2.2 (in the form of a section of the front brake circuit K2) in such a way that, based on a weight status signal of the mobile crane 1 that can be generated from the hydropneumatic suspension 12, a brake pressure P1 that can be regulated within the second front brake circuit section K2.2 via the automatic load-dependent brake force regulator 14 can be adjusted compared to the brake pressure P1 that is simultaneously controlled within the first front brake circuit section K2.1 and the rear brake circuit K1. For this purpose, the automatic load-dependent brake force regulator 14 has a control input 15 fluidly coupled to the relevant suspension circuits 13a, 13b of the hydropneumatic suspension 12, so that their respective pressure can be used as the weight status signal used to control the automatic load-dependent brake force regulator 14.

[0042] The structural design and / or adjustment can be selected such that the brake pressure P1 present within the second front brake circuit section K2.2 corresponds to the brake pressure P2 simultaneously present within the first front brake circuit section K2.1 without any change by the automatic load-dependent brake force regulator 14. The brake pressures P1, P2—in the front brake circuit K2, which is composed of the first and second front brake circuit sections K2.1, K2.2—can correspond to or deviate from the brake pressure P3 simultaneously prevailing in the rear brake circuit K1. List of reference symbols

[0043] 1 Mobile crane 2 Vehicle cabin 3a Wheel, right 3b Wheel, left 4a Wheel brake, right 4b Wheel brake, left 5 Braking system 6a Pneumatic pump 6b Pneumatic pump 7 Air dryer 8 Air tank 9 Separator 10 Brake pedal 10a Valve 10b Valve 11 Lever 12 Hydropneumatic suspension 13a Suspension circuit, right 13b Suspension circuit, left 14 Automatic load-dependent brake force regulator 15 Control input 16 Protection valve A1 Vehicle axle, front A2 Vehicle axle, front A3 Vehicle axle, center A4 Vehicle axle, center A5 Vehicle axle, center A6 Vehicle axle, rear A7 Vehicle axle, rear A8 Vehicle axle, rear K1 Brake circuit, rear K2 Brake circuit, front K2.1 Brake circuit section, first front K2.2 Brake circuit section, second front K3 Brake circuit, third K4 Pressure circuit L Pneumatic line P1 Brake pressure P2 brake pressure P3 brake pressure

Claims

1. Vehicle crane (1) comprising hydropneumatic suspension (12) and comprising a braking system (5) having wheel brakes (4a, 4b) and having a first braking circuit (K1) assigned to the wheel brakes (4a, 4b) of at least one vehicle axle (A6, A7, A8) and at least a second braking circuit (K2) assigned to the wheel brakes (4a, 4b) of at least one further vehicle axle (A1, A2, A3, A4, A5),characterised in that the hydropneumatic suspension (12) is coupled to at least one automatic load-dependent braking force regulator (14) which is operatively connected to one of the braking circuits (K1, K2) or one of the braking circuit portions (K2.1, K2.2) thereof such that, on the basis of a weight state signal of the vehicle crane (1) which can be generated from the hydropneumatic suspension (12), a braking pressure (P1) which can be generated within the braking circuit (K2) or braking circuit portion (K2.2) coupled to the automatic load-dependent braking force regulator (14) can be changed in relation to a braking pressure (P2, P3) which can be generated simultaneously within the other braking circuit (K1) or braking circuit portion (K2.1), wherein the braking pressure (P1) that can be generated within the braking circuit (K2) or braking circuit portion (K2.2) coupled to the automatic load-dependent braking force regulator (14) corresponds to the braking pressure (P2, P3) that can be generated simultaneously within the other braking circuit (K1) and / or braking circuit portion (K2.1) without being changed by the automatically load-dependent braking force regulator (14), wherein the braking pressure (P1) that can be generated within the braking circuit (K2) or braking circuit portion (K2.2) coupled to the automatic load-dependent braking force regulator (14) can be regulated, in particular can be reduced, by the automatic load-dependent braking force regulator (14) compared with the value of the braking pressure (P2, P3) that can be generated simultaneously within the other braking circuit (K1) and / or braking circuit portion (K2.1).

2. Vehicle crane (1) according to claim 1, characterised in that a regulation input (15) is arranged on the automatic load-dependent braking force regulator (14), which regulation input is fluid-conductingly coupled to the hydropneumatic suspension (12) such that the relevant pressure thereof can be used as the weight state signal serving to control the automatic load-dependent braking force regulator (14).

3. Vehicle crane (1) according to claim 2, characterised in that at least one suspension circuit (13a, 13b) of the hydropneumatic suspension (12) is assigned to the regulation input (15), and this at least one suspension circuit (13a, 13b) is also assigned to at least some of the vehicle axles (A1 to A8) which are assigned to the relevant automatic load-dependent braking force regulator (14).

4. Vehicle crane (1) according to claim 3, characterised in that the at least one suspension circuit (13a, 13b) is assigned precisely to the vehicle axles (A1 to A8) which are assigned to the relevant automatic load-dependent braking force regulator (14).

5. Vehicle crane (1) according to any of the preceding claims, characterised in that the automatic load-dependent braking force regulator (14) is connected on the control side to the hydropneumatic suspension (12) and has a regulating range of up to a maximum of 160 bar, preferably 200 bar.

6. Vehicle crane (1) according to claim 5, characterised in that the automatic load-dependent braking force regulator (14) has a pressure resistance outside the regulating range thereof of up to a maximum of 250 bar, preferably 300 bar and particularly preferably 350 bar, or a protection valve with corresponding pressure resistance is connected upstream of the automatic load-dependent braking force regulator (14).

7. Vehicle crane (1) according to any of the preceding claims, characterised in that the braking circuit (K2) or braking circuit portion (K2.2) operatively connected to the automatic load-dependent braking force regulator (14) is assigned to one or more, in particular front, vehicle axles (A1 to A5).

8. Vehicle crane (1) according to any of the preceding claims, characterised in that the hydropneumatic suspension (12) has a levelling system.

9. Vehicle crane (1) according to any of the preceding claims, characterised in that the hydropneumatic suspension (12) has an axle load compensation within a suspension circuit (13a, 13b).

10. Vehicle crane (1) according to any of the preceding claims, characterised in that two or more automatic load-dependent braking force regulators (14) are provided, wherein each of these automatic load-dependent braking force regulators (14) is coupled to one of the braking circuits (K1, K2) or braking circuit portions (K2.1, K2.2).

11. Vehicle crane (1) according to claim 10, characterised in that the automatic load-dependent braking force regulators (14) are set to be the same or different from one another, in particular with regard to their regulation and / or response behaviour.

12. Vehicle crane (1) according to any of the preceding claims, characterised in that the braking system (5) is pneumatic.

13. Vehicle crane (1) according to any of the preceding claims, characterised in that the number of vehicle axles (A1 to A8) is at least three.

14. Vehicle crane (1) according to any of the preceding claims, characterised in that the number of braking circuits (K1, K2) or braking circuit portions (K2.1, K2.2) is greater than the number of automatic load-dependent braking force regulators (14).