Hydraulic system for a motorhome, motorhome with such a hydraulic system, and method for extending or retracting at least two hydraulic support cylinders

Abstract

Hydraulic systems (10) for a motorhome (100) for supporting the motorhome (100) on a surface (2) are known. Such a hydraulic system (10) has at least one rear support cylinder (60C, 60D) and at least one front support cylinder (60A, 60B) for extending ground supports (160). It further has a hydraulic pump (20) which is connected via a first extension line (12A) and a first retraction line (12B) to the at least one rear support cylinder (60C, 60D) and via a second extension line (14A) and a second retraction line (14B) to the at least one front support cylinder (60A, 60B). Each of the support cylinders (60A, 60B, 60C, 60D) is assigned a switchable control valve (50). It is proposed to arrange at least one flow control valve (42) in at least one of the extension lines (12A, 14A) and / or in at least one of the insertion lines (12B, 14B) in order to selectively limit the volume flow to some support cylinders (60A, 60B, 60C, 60D).

Description

SCOPE OF APPLICATION AND STATE OF THE ART

[0001] The invention primarily relates to a hydraulic system for a motorhome vehicle and a corresponding motorhome vehicle.

[0002] Motorhomes often have extendable floor supports to stabilize the vehicle when stationary and, in particular, to bring it into a completely horizontal position.

[0003] These floor supports are typically extended and retracted by means of hydraulic support cylinders, which are supplied with pressurized hydraulic fluid by a hydraulic pump. Typically, a motorhome of this type, as well as a motorhome according to the invention, has four floor supports and thus four support cylinders, which are provided in pairs at the front and rear of the vehicle, with one floor support on the right side of the vehicle and one on the left side.

[0004] It is desirable that the alignment of the vehicle is uniform, especially during the extension of the ground supports, unless individual support cylinders are extended separately in phases for the purpose of achieving horizontal alignment.

[0005] Achieving uniform extension of the support legs is not easy in practice, as the proportion of the vehicle's total load borne by each support leg varies. In particular, the front support legs may have to bear a higher load than the rear ones due to the front-mounted engine and / or transmission. If the hydraulic pump simultaneously supplies pressurized hydraulic fluid to the support cylinders of all support legs already in contact with the ground, the cylinders of the less heavily loaded legs tend to extend first. Only when the operating pressure on the cylinders of the less loaded legs increases—for example, because their load increases or they reach their end position—do the cylinders of the initially more heavily loaded legs begin to extend. TASK AND SOLUTION

[0006] The primary object of the invention is to provide a hydraulic system for a motorhome of the type described, which reduces the aforementioned problem.

[0007] This document proposes a hydraulic system for stabilizing a motorhome on a surface. This system comprises at least one rear support cylinder and at least one front support cylinder for extending support legs. Preferably, the hydraulic system has at least four support cylinders, two of which are located on front support legs and two on rear support legs. In addition to the hydraulic system itself, both before and after its integration into a motorhome, a motorhome equipped with such a hydraulic system is also proposed. This motorhome preferably has rear and front support legs, in particular two rear and two front support legs, each of which can be vertically displaced by means of a support cylinder.

[0008] The support cylinders are designed as double-acting cylinders. By pressurizing an extension line supplying the respective cylinder, the cylinder is extended, and by pressurizing a retraction line, the cylinder is retracted.

[0009] The hydraulic system includes a hydraulic pump for extending and retracting the support cylinders and thus the vehicle's ground supports. The hydraulic pump is driven by an electric motor, preferably a brushless DC motor, as this allows the hydraulic pump to operate across a wide flow rate range.

[0010] The hydraulic pump is connected to at least one rear-mounted support cylinder via a first extension line and a first retraction line, and to at least one front-mounted support cylinder via a second extension line and a second retraction line. The respective extension and retraction lines are not usually completely separate from each other, but rather form branches fed by a common extension and retraction line.

[0011] Each of the support cylinders is assigned a switchable control valve, particularly in the respective extension line. These are preferably solenoid valves, which are usually switchable only between a defined open and a closed state. The respective control valve allows the pressure application to the support cylinder to be individually prevented or enabled. The control valve is typically controlled via electrical control lines, by means of which the control valves are connected to a central control unit. Additionally, according to the invention, a flow control valve is arranged in at least one retraction line or, in particular, in at least one extension line. Such a flow control valve is designed to ensure a defined fluid flow.This is achieved by the flow control valve maintaining a constant pressure difference between an inlet and an outlet using a differential pressure valve. Furthermore, the flow control valve has a throttling device that allows the flow rate to be adjusted while maintaining this constant pressure difference. The term "throttling device" is used here in a general sense. Besides a classic throttle with a smooth cross-sectional transition to a constricted throttling point, it can also include an adjustable orifice plate.

[0012] The flow control valve is arranged such that, when the support cylinders are extended or retracted simultaneously, at least one support cylinder is supplied via the flow control valve, while at least one other support cylinder is not supplied via this flow control valve, but possibly via a second flow control valve that can be adjusted independently of the first. The hydraulic lines effectively form two hydraulic circuits, which include partially overlapping lines, with the aforementioned flow control valve being located in a branch of one of the hydraulic circuits that is not simultaneously part of the other hydraulic circuit.

[0013] In principle, it is conceivable to assign a separate flow control valve to each support cylinder. However, this is economically disadvantageous and therefore usually avoided. It is considered particularly advantageous if two support cylinders are connected to the hydraulic pump via a common flow control valve in a shared branch of one of the extension or retraction lines, especially two rear support cylinders or two front support cylinders. In a typical configuration with four support cylinders, the other two support cylinders are connected to the hydraulic pump either without an intermediate flow control valve or via a second flow control valve.

[0014] It can also be advantageous if at least one support cylinder has no flow control valve in either the extension or retraction line. In such a system, there is at least one support cylinder where the supplied flow rate is specifically controlled via the flow control valve, while this is not possible in the same way for at least one other support cylinder. However, this can be functionally compensated for by appropriately controlling the pump flow rate of the hydraulic pump that supplies both or all support cylinders. The flow rate to the at least one support cylinder without a flow control valve is the difference between the pump flow rate and the flow rate of the support cylinder with a flow control valve.

[0015] The use of the flow control valve according to the invention makes it possible to extend the support cylinders uniformly despite differing loads on the different base supports and thus on the support cylinders themselves. The flow control valve limits the fluid flow supplied to the support cylinder under light load, so that the at least two support cylinders are supplied with coordinated and preferably essentially identical fluid flows and can therefore be extended and retracted at the same speed.

[0016] The use of a hydraulic system with at least one flow control valve is particularly advantageous when the weight load of the motorhome vehicle is unevenly distributed between the front and rear areas, especially when a front axle or a rear axle is loaded with more than 60% of the vehicle's weight.

[0017] Especially in motorhomes where the engine and / or transmission are located at the front, the vehicle's unladen weight is primarily concentrated at the front. The typically used front-wheel drive also increases the weight distribution between the front and rear axles. In addition to the inherent uneven weight distribution resulting from the motorhome's unladen weight, additional cargo can also affect the vehicle's weight distribution and potentially lead to different weight distributions on the rear and front support legs. For example, a motorhome might have a rear garage for a passenger car. If a small car weighing, say, 700 kg is stored there, the weight resting on the rear support legs could be greater than the weight on the front.

[0018] The at least one flow control valve is designed to compensate for the weight differences between the front and rear of the vehicle with regard to the extension of the support cylinders. The flow control valve acts as a balancing component, preventing the hydraulic oil delivered by the hydraulic pump from flowing exclusively or predominantly to the less heavily loaded support cylinders. Since the rear of motorhomes is usually lighter than the front, a flow control valve is preferably assigned to the rear support cylinders.

[0019] The at least one flow control valve increases the energy consumption of the hydraulic pump. It is therefore advantageous to be able to bypass it when not in use. Such a situation might arise, for example, when the other support cylinders are disconnected from the hydraulic pump via their control valves, so that the full flow rate of the hydraulic pump is directed into the branch of the hydraulic system equipped with the flow control valve.

[0020] For the purpose of bypassing, it is preferably provided that at least one flow control valve is assigned a bypass line and a control valve. The control valve is located upstream or downstream of the bypass line and flow control valve line, which are connected in parallel. The control valve can switch between the two lines electrically. If it disconnects the flow control valve line, the entire flow rate passes through the bypass line.

[0021] The use of the flow control valve is particularly advantageous when extending the support cylinders. It is therefore preferably arranged in the extension line such that the hydraulic fluid flowing into the support cylinder is regulated by the flow control valve, or arranged in the retraction line such that the hydraulic fluid flowing back to the hydraulic tank is regulated by the flow control valve.

[0022] However, it may be desirable to utilize the compensating effect of the flow control valve even when retracting the support cylinders. To enable this, it can be advantageous to assign a hydraulic rectifier circuit to the flow control valve. This ensures that, regardless of the flow direction in the relevant line, the flow control valve is subjected to the same flow direction. One possible design for this is a so-called Graetz circuit.

[0023] As already explained, the advantage of using a flow control valve lies particularly in its ability to compensate for uneven weight distribution between the front and rear of the vehicle with regard to the extension of the support cylinders. Since this uneven weight distribution is typically largely due to the vehicle's unladen weight, and especially to a front-mounted engine and transmission, a simple embodiment of a hydraulic system according to the invention may require the flow control valves to be set once and then remain unchanged with respect to their flow rate during operation. For this purpose, flow control valves that are solely mechanically adjustable, for example by means of a rotatable actuator such as an adjusting screw, are sufficient.

[0024] However, it is advantageous if at least one flow control valve is designed as an electrically adjustable flow control valve. This means that the fluid flow can be adjusted as needed by means of an electrical signal. This allows the fluid flow to be appropriately adjusted even under changing load conditions, for example, when the front or, in particular, the rear weight load of the vehicle is significantly increased due to additional cargo.

[0025] The control of the at least one electrically adjustable flow control valve is preferably carried out by an electronic control unit directly integrated into the hydraulic system or the motorhome as a whole. This is preferably a single control unit that not only controls the at least one flow control valve, but also the control valves of the individual support cylinders, as well as the hydraulic pump and, if applicable, its delivery rate. If the vehicle has other hydraulic consumers, these are also preferably controlled by the single control unit.

[0026] In particular, the electronic control unit can be designed to control at least one current control valve depending on at least one weight parameter of the motorhome vehicle and / or depending on the sensor data of at least one tilt sensor.

[0027] The weight parameters used here can be, in particular, the axle loads on a front axle and / or a rear axle, or the standing forces detected at the vehicle's ground supports, which can be detected by local force, pressure or strain sensors or indirectly via the hydraulic fluid pressure in the support cylinders.

[0028] If sensor data on inclination are used to control the at least one flow control valve, this data can come from a single inclination sensor or include sensor data from several inclination sensors to also take into account any possible torsion of the vehicle during control.

[0029] Preferably, the flow control valve is controlled by the control unit such that the weight and / or inclination parameters are repeatedly recorded during the extension and retraction movements, and the at least one flow control valve is continuously adjusted accordingly, resulting in a closed control loop. Control can be achieved either by the flow control valve variably limiting the flow in its branch, or by generating an excess flow in another branch, i.e., a flow rate greater than that in the branch controlled by the flow control valve. In particular, the control unit can also variably adjust the speed of the hydraulic pump's electric motor and thus the pump's delivery volume for control purposes.

[0030] The invention also relates to a method for extending or retracting at least two hydraulic support cylinders of a motorhome, which is preferably carried out using the hydraulic system described above. The at least two support cylinders are supplied by a common hydraulic pump and are each connected to the hydraulic pump via an extension line and / or a retraction line. A first flow control valve is arranged in at least one extension line or retraction line.

[0031] The procedure stipulates that, at least during a partial phase of the extension or retraction process, but particularly during the extension of the support cylinders and thus the ground supports, at least two support cylinders are simultaneously supplied with pressurized hydraulic fluid. The supply to at least one of the support cylinders is provided through the flow control valve, while the supply to at least one other support cylinder is not provided through the flow control valve or through a second, separately adjustable flow control valve.

[0032] An operation in which at least one other support cylinder operates without an associated flow control valve allows for the targeted control of at least two support cylinders in a structurally simple manner. For this purpose, the flow control valve of at least one support cylinder is set to a defined flow rate, and the flow rate of the hydraulic pump is adjusted so that the flow supplied to the at least one other support cylinder reaches the desired height. For example, the flow rate to the two rear support cylinders could be set to 2 liters / minute, and the pump flow rate to 3 liters / minute to ensure that 1 liter / minute is supplied to the two front support cylinders.

[0033] Alternatively, it may also be useful to supply different support cylinders, in particular different groups of support cylinders with several support cylinders each, via different flow control valves with different volume flows, for example, to provide one flow control valve each for the front and rear support cylinders, whereby during the execution of the process the front support cylinders are supplied with a volume flow of 1 liter / minute in phases, while the rear support cylinders are supplied with a volume flow of 2 liters / minute.

[0034] At least in phases, the volume flows at the at least two flow control valves are preferably set to differ from each other by at least 20%.

[0035] In the manner described above, the method allows two support cylinders of the motorhome vehicle, which are under different loads, to be supplied simultaneously with defined volume flows of hydraulic fluid.

[0036] The phase in which the described simultaneous supply, influenced by the control valve, takes place is preferably only a sub-phase of a more comprehensive extension process.

[0037] It is particularly preferred that, prior to this sub-phase, in an initial phase, the at least two and preferably four support cylinders are extended a portion of the way, particularly until they make contact with the ground, without using the flow control valve. This initial phase preferably involves extending the support cylinders at least partially sequentially, i.e., one after the other. In particular, the support cylinders can be partially extended in groups, for example, first the front or rear support cylinders until they make contact with the ground, and then the other support cylinders until they too make contact. The fact that the flow control valve is not used in this initial phase, but rather bypassed via a bypass line, reduces energy consumption.

[0038] In the described sub-phase, in which at least one support cylinder is supplied without an intermediate flow control valve and at least one support cylinder is supplied with an intermediate flow control valve, all support cylinders of the system can be extended simultaneously, typically two front and two rear. However, it is also conceivable that, at least temporarily during this sub-phase, at least one rear and at least one front support cylinder are extended simultaneously, while at the same time at least one rear and / or at least one front support cylinder is disconnected from the hydraulic pump via a control valve. Such operation is particularly useful when compensating for a tilt of the vehicle around its longitudinal direction, i.e., when only the right-hand or only the left-hand outriggers of the vehicle need to be extended further.

[0039] The invention also includes an alternative design to the hydraulic system described above for a motorhome, as well as a motorhome equipped with this alternative hydraulic system. As with the hydraulic system described above, the hydraulic system according to this alternative has at least one rear support cylinder and at least one front support cylinder for extending floor supports, as well as a hydraulic pump connected to the at least one rear support cylinder via a first extension line and a first retraction line, and connected to the at least one front support cylinder via a second extension line and a second retraction line.

[0040] According to this alternative design, the first inlet line and the second inlet line, or the first outlet line and the second outlet line, are connected to each other via a hydraulic flow divider. Such a flow divider, which can be designed, for example, with a slide valve or as a gear divider, divides an incoming volume flow into two partial flows in a defined ratio or combines two partial flows into an outgoing volume flow in a defined ratio. Particularly preferably, in a hydraulic system according to the invention, such a flow divider is designed so that the two generated or combined partial flows are of equal magnitude, with the accuracies of known flow dividers typically being around ±5% or less.

[0041] The flow divider ensures that the volume flow supplied to or discharged from the at least one front-facing support cylinder and the volume flow supplied to or discharged from the at least one rear-facing support cylinder are approximately identical.

[0042] As with the use of a flow control valve, it is possible to extend support cylinders bearing uneven weight loads at the same speed using a flow divider. Nevertheless, the solution with at least one flow control valve is preferred because it is more energy-efficient.

[0043] Since it should preferably remain possible to disconnect support cylinders individually from the hydraulic pump even when using a hydraulic flow divider, a bypass line and a control valve for controlling the flow to the hydraulic flow divider and the bypass line are preferably assigned to the hydraulic flow divider. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Further advantages and aspects of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention, which are explained below with reference to the figures. Fig. Figure 1 shows a motorhome vehicle according to the invention with four floor supports in an overall view. Fig. Figure 2 shows a first embodiment of a hydraulic system according to the invention for the vehicle of the Fig. 1. Fig. Figure 3 shows a second embodiment of a hydraulic system according to the invention for the vehicle of the Fig. 1. Fig. Figure 4 shows a third embodiment of a hydraulic system according to the invention for the vehicle of the Fig. 1. Fig. Figure 5 shows an alternative design of a hydraulic system according to the invention for the vehicle of the Fig. 1. Fig. Figure 6 shows a first flow control valve with manual adjustability for a hydraulic system of the Fig. 2 to 4. Fig. Figure 7 shows a second flow control valve with electrical adjustability for a hydraulic system of the Fig. 2 to 4. DETAILED DESCRIPTION OF THE EXECUTION EXAMPLES

[0045] Fig. Figure 1 shows a motorhome vehicle 100 according to the invention. This motorhome vehicle 100 has a front axle 108 and a rear axle 110, as well as a total of four ground supports 160, which can be extended vertically to support the vehicle 100. In the Fig. 1. Each of these floor supports 160 is assigned a support cylinder 60A, 60B, 60C, 60D in a non-removable manner.

[0046] The motorhome vehicle 100 has a front-mounted drive motor 104 and a front-mounted drive transmission 106. This allows the front axle 108 to be driven. However, a transmission shaft can also be provided at the rear of the vehicle to drive the rear axle 110 instead or in addition to the front axle. Due to the arrangement of the drive motor 104 and the drive transmission 106 at the front of the vehicle 100, this is where the greatest load of the vehicle is concentrated.

[0047] The motorhome vehicle 100 can be equipped with a rear garage 102 to allow it to accommodate another vehicle, especially a small car, for use at the holiday destination, for example.

[0048] A hydraulic system is provided for extending the 160 floor supports. Three possible designs of a hydraulic system are described in the Fig. Figures 2 to 4 are shown. The following explanation of the exemplary embodiment of the Fig. 2 also applies to the design of the Fig. 3 and Fig. 4, unless otherwise stated.

[0049] The hydraulic system 10 of the Fig. 2 has a hydraulic tank 16 from which hydraulic fluid can be pumped by means of a hydraulic pump 20 into a central extension line 11A or a central retraction line 11B. The hydraulic pump 20 is electrically driven by a motor 30, which is preferably a brushless DC motor, which in particular allows the hydraulic pump 20 to be operated with a highly variable delivery rate.

[0050] Depending on the pumping direction of the hydraulic pump 20, this hydraulic fluid is delivered to either the central extension line 11A or the central retraction line 11B. The central extension line 11A splits into two branches 12A and 14A. Branch 12A leads to the support cylinders 60C and 60D associated with the rear outriggers 160, while branch 14A leads to the support cylinders 60A and 60B of the front outriggers 160. Each support cylinder 60A, 60B, 60C, and 60D is equipped with a control valve 50 and an electrically switchable check valve 54. The control valve 50 allows the fluid supply to the respective support cylinder 60A, 60B, 60C, and 60D to be completely shut off. The switchable check valves 54 make it possible to maintain the fluid pressure in a pressure chamber provided above the respective piston of the support cylinders 60A, 603, 60C, 60D without having to keep the entire hydraulic system under pressure.

[0051] To extend the support cylinders 60A, 603, 60C, 60D, hydraulic fluid is pumped into the central extension line 11A and thus, with the control valves 50 open, enters the support cylinders 60A, 60B, 60C, 60D and moves the respective pistons downwards.

[0052] In the line branch 12A assigned to the rear support cylinders 60C, 60D, an additional valve arrangement is provided, comprising a control valve 46, a flow control valve 42, and a bypass line 44. When the hydraulic fluid is directed through the flow control valve 42 via the control valve 46, the latter can limit the flow rate towards the support cylinders 60C, 60D. This ensures that the flow rate towards the front support cylinders 60A, 60B and the flow rate towards the rear support cylinders 60C, 60D are equal, so that the floor supports 160 are extended evenly and the vehicle is raised evenly, if necessary.

[0053] The Fig. 6 and Fig. Figure 7 shows a schematic representation of a flow control valve. The flow control valve 42 of the Fig. 6 has an inlet 42A and an outlet 42B. A differential pressure valve 42C and a throttling device 42E are provided between them. The differential pressure valve has a control piston 42D, which is actuated by a spring relative to Fig. The spring is pre-tensioned and pressed to the left. The differential pressure between inlet 42A and outlet 42B can be precisely adjusted via the spring setting. If the pressure at outlet 42B is lower than at inlet 42A, the inlet fluid pressure shifts the control piston 42D to the right, thus increasing the flow resistance through the flow control valve 42. In this way, the differential pressure valve ensures that a constant pressure difference is maintained between inlet 42A and outlet 42B. A constant pressure difference means that the flow rate is defined solely by the opening cross-section and is therefore adjusted linearly and independently of the load via the adjustable throttling device 42E downstream of the differential pressure valve 42C.

[0054] This throttle device has a throttle body 42F which, in the case of the design of the Fig. The position of the pressure differential valve 42C and the throttling device 42E can be adjusted by means of a control wheel 42G to increase or decrease the throttling effect. The pressure difference between the inlet and outlet, caused by the differential pressure valve 42C and the throttling device 42E, influences the volume flow rate. A constant pressure difference results in a substantially constant fluid flow rate.

[0055] In the design according to Fig. 7. The design of the flow control valve is essentially identical to that of the Fig. 6. The only difference is that no adjusting wheel 42G is provided for manual operation. Instead, a drive motor 42H is provided, by means of which the throttling effect of the throttling device 42E can be adjusted and thus the volume flow regulated.

[0056] In Fig. Figure 2 shows a schematic representation of a control unit 70, which is connected to the controllable components 50, 54, 42, 46, 30 of the hydraulic system 10. Tilt sensors 72 and weight sensors 74 are assigned to the control unit 70. The control unit 70 evaluates their sensor data to determine the current orientation and / or weight distribution of the vehicle 100 and to control the valves 46, 52, 50, 54 accordingly.

[0057] This, in conjunction with the arrangement of the flow control valve 42 in line branch 12A, ensures in particular that the flow rate in line branch 12A is adapted to the flow rate in line branch 14A, thereby achieving the aforementioned uniform extension speed. However, the flow control valve 42 and the hydraulic pump 20 can also be set such that different flow rates result in line branches 12A and 14A.

[0058] To retract the outriggers 160, the hydraulic pump 20 delivers hydraulic fluid into the central retraction line 11B. This pressurizes the pressure chamber located beneath the pistons of the outrigger cylinders 60A, 60B, 60C, and 60D. The fluid above the piston is conveyed back towards the hydraulic tank 16 via the branch lines 12A and 14A, the central extension line IIA, or directly from the control valves 50. During this process, the switchable check valves 54 are open, and the flow control valve 42 is deactivated by the corresponding switching positions of the control valve 46.

[0059] The functioning of the hydraulic system 10 of the Fig. 3 is largely identical to that of the Fig. 2. The control unit 70 is not shown here, however, accordingly Fig. 2 available.

[0060] The only difference in the design of Fig. 3 for the design of the Fig. The advantage lies in the fact that the flow control valve 42 is embedded in a rectifier circuit 48, in particular a Graetz circuit. This ensures that the hydraulic fluid flowing through line branch 12A is directed through the flow control valve 42 regardless of the flow direction, i.e., regardless of whether the support cylinders are being extended or retracted, and thus the flow rate can be precisely adjusted. This arrangement therefore makes it possible to achieve a uniform travel speed even when retracting the support cylinders 60A, 60B, 60C, 60D.

[0061] The design of the Fig. 4 essentially corresponds to that of the Fig. 2. Again, the control unit (70) is not shown here, but is nevertheless present. The difference in the design of Fig. 4 for the design of the Fig. The advantage lies in the fact that both in line branch 12A and in line branch 14A of the extension line, a valve arrangement 40 with a flow control valve 42 is provided. This allows the fluid supply to the support cylinders 60A, 60B and / or to the support cylinders 60C, 60D to be selectively adjusted with regard to their fluid flow. Such a design can be particularly advantageous if, depending on the payload, the load on the rear support cylinders 60A, 60B may be greater than that on the front support cylinders 60C, 60D. This occurs, for example, if a car is present in the rear garage 102.

[0062] In one variant of the design, not shown, Fig. 4. The flow control valves 42 located there, or one of these flow control valves, could also be equipped with the rectifier circuit described above. In further variants not shown, the flow control valve(s) could also be provided in corresponding line branches leading from the central inlet line 11B, 12B, 14B. Furthermore, configurations are also possible in which the flow control valves 42 are not electrically controlled, but rather in the manner of… Fig. 6 are designed and are therefore uniquely and permanently set.

[0063] Fig. Figure 5 shows an alternative design of a hydraulic system. Here, the designs differ from those of the Fig.Figures 2 to 4 provide that the coordinated flow to the control cylinders 60A, 60B on the one hand and the control cylinders 60C, 60D on the other hand is provided via a flow divider 80, which can be activated phase-wise by a control valve 84 or bypassed by a bypass line 82. If the support cylinders 60A, 60B, 60C, 60D are supplied via the flow divider, it is ensured that a fixed or variably adjustable flow ratio is maintained between the flow to line branch 14A and line branch 12A. In particular, the flow divider 80 can thus ensure that the same quantity of fluid is delivered to the front support cylinders 60A, 60B and to the rear support cylinders 60C, 60D, and that the vehicle is therefore raised evenly.

Claims

[1] Hydraulic system (10) for a mobile home (100) for supporting the mobile home (100) on a surface (2) having the following features: a. the hydraulic system (10) has at least one rear support cylinder (60C, 60D) and at least one front support cylinder (60A, 60B) for extending ground supports (160), and b. the hydraulic system (10) comprises a hydraulic pump (20) which is connected to the at least one rear support cylinder (60C, 60D) via a first extension line (12A) and a first retraction line (12B) and is connected to the at least one front support cylinder (60A, 60B) via a second extension line (14A) and a second retraction line (14B), and c. each of the support cylinders (60A, 60B, 60C, 60D) is assigned a switchable control valve (50), characterized by the following additional feature: d. at least one flow control valve (42) is arranged in at least one of the extension lines (12A, 14A) and / or in at least one of the entry lines (12B, 14B). [2] Hydraulic system (10) according to claim 1 with the following additional feature: a. no flow control valve is provided in at least the extension lines (14A) and the retraction lines (14B) of at least one support cylinder (60A, 60B). [3] Hydraulic system (10) according to claim 1 or 2 with the following additional feature: a. the at least one flow control valve (42) is arranged in the first extension line (12A) or the first retraction line (12B) and is thus assigned to the at least one rear-side support cylinder (60C; 60D). [4] Hydraulic system (10) according to claim 1 or 2 of any of the preceding claims with the following additional feature: a. the flow control valve (42) is a common flow control valve (42) for several support cylinders, in particular with the following additional feature: b. the flow control valve (42) is arranged in a common line branch of one of the extension lines (12A, 14A) or one of the retraction lines (12B, 14B), via which exclusively rear-side support cylinders (60C, 60D) or exclusively front-side support cylinders (60A, 60B) are connected to the hydraulic pump (20). [5] Hydraulic system (10) according to one of the preceding claims with the following additional feature: a. a bypass line (44) and a control valve (46) for controlling the inflow to the flow control valve (42) and the bypass line (44) are assigned to the at least one flow control valve (42). [6] Hydraulic system (10) according to one of the preceding claims with the following additional feature: a. a hydraulic rectifier circuit (48) is assigned to the at least one flow control valve (42), so that regardless of the flow direction, the flow through the flow control valve (42) is in the same direction, preferably with the following additional feature: b. the hydraulic rectifier circuit (48) is a Graetz circuit. [7] Hydraulic system (10) according to one of the preceding claims with the following additional feature: a. the at least one flow control valve (42) is designed as an exclusively mechanically adjustable flow control valve (42), preferably with the following additional feature: b. the flow control valve (42) is adjustable via a rotary actuator, in particular via an adjusting screw. [8] Hydraulic system (10) according to one of claims 1 to 5 with the following additional feature: a. the at least one flow control valve (42) is designed as an electrically adjustable flow control valve (42). [9] Hydraulic system (10) according to claim 8 with the following additional feature: a. the hydraulic system (10) is equipped with an electronic control device (70) which is designed to control the at least one flow control valve (42) as a function of at least one weight parameter of the mobile home vehicle (100), in particular with at least one of the following additional features: b. the control device is designed to control the flow control valve (42) as a function of at least one axle load, and / or c. the control device is designed to control the flow control valve (42) as a function of a standing force detected at the ground supports, and / or d. the control device is designed to continuously adjust the flow control valve (42) depending on the temporal course of the at least one weight parameter. [10] Hydraulic system (10) according to claim 8 or 9 with the following additional feature: a. the hydraulic system (10) is equipped with an electronic control device which is designed to control the at least one flow control valve (42) as a function of sensor data from an inclination sensor (72), in particular with at least one of the following additional features: b. the control device is designed to control the flow control valve (42) depending on sensor data from at least two inclination sensors (72), and / or c. the control device is designed to continuously adjust the flow control valve (42) depending on the temporal progression of the at least one inclination value. [11] Hydraulic system (10) according to one of the preceding claims with at least one of the following additional features: a. the switchable control valves (50) are solenoid valves which can in particular only be switched between a defined open and a closed state, and / or b. the at least one flow control valve (42) comprises a pressure difference valve (42C) and an adjustable throttle device (42E), and / or c. the hydraulic pump (20) has a brushless DC motor (30) as the drive unit (30). [12] Motorhome vehicle (100) with the following feature: a. the mobile home (100) has at least two extendable floor supports (160), of which at least one floor support (160) is provided at the rear and at least one floor support (160) is provided at the front, characterized by the following additional feature: b. a hydraulic system (10) according to one of claims 1 to 10 is provided for extending and retracting the ground supports (160). [13] A mobile home vehicle (100) according to claim 12, comprising at least one of the following additional features: a drive motor (104) of the mobile home vehicle (100) is arranged at the front of the vehicle and / or b. a drive gear (106) of the mobile home (100) is arranged at the front of the vehicle, and / or c. at least 60% of the load of the motorhome vehicle (100) without payload rests on a front axle (108), and / or d. the mobile home vehicle (100) has a driven front axle (108), wherein preferably only the front axle (108) is driven. [14] A mobile home vehicle (100) according to claim 12 or 13, having the following additional feature: a. the mobile home vehicle (100) has a rear garage (102) for accommodating a passenger car. [15] Method for extending or retracting at least two hydraulic support cylinders (60A, 60B, 60C, 60D) of a mobile home vehicle (100) having the following features: a. for extending and / or retracting the at least two hydraulic support cylinders (60A, 60B, 60C, 60D), a common hydraulic pump (20) is provided, which can be connected to the hydraulic pump (20) via an extension line (12A, 14A) and / or a retraction line (12B, 14B), and b. a first flow control valve (42) is arranged at least in one extension line (12A, 14A) or in one entry line (12B, 14B), and c. during the retraction or extension, the at least two support cylinders (60A, 60B, 60C, 60D) are supplied with hydraulic fluid at least in a partial phase, wherein the supply with regard to at least one of the support cylinders (60C, 60D) takes place through the flow control valve (42) and wherein the supply with regard to at least one other of the support cylinders (60A, 60B) does not take place through the flow control valve (42) or through a second flow control valve (42). [16] Method according to claim 15 with the following further feature: a. the supply with respect to the at least one other support cylinder (60A, 60B) takes place without the hydraulic fluid being passed through a second flow control valve. [17] Method according to claim 15 with the following further feature: a. the supply with respect to the at least one other support cylinder (60A, 60B) is effected by a second flow control valve (42), wherein the volume flows through the two flow control valves (42) are of different sizes. [18] Method according to one of claims 15 to 17 with the following further feature: preferably with at least one of the following additional features: a. in the course of the extension, before the partial phase, the at least two support cylinders (60A, 60B, 60C 60D) are extended over a partial distance, in particular up to ground contact, without using the flow control valve (42), wherein in particular the support cylinders are extended at least partially sequentially one after the other, and / or b. during the partial phase, at least one rear and at least one front support cylinder are extended simultaneously, wherein at least one rear or at least one front support cylinder is separated from the hydraulic pump (20) via a control valve (50). [19] Hydraulic system (10) for a mobile home (100) for supporting the mobile home (100) on a surface (2) having the following features: a. the hydraulic system (10) has at least one rear support cylinder (60C, 60D) and at least one front support cylinder (60A, 60B) for extending ground supports, and b. the hydraulic system (10) comprises a hydraulic pump (20) which is connected to the at least one rear support cylinder (60C, 60D) via a first extension line (12A) and a first retraction line (12B) and is connected to the at least one front support cylinder (60A, 60B) via a second extension line (14A) and a second retraction line (14B), and c. the first inlet line (12B) and the second inlet line (14B) and / or the first extension line (12A) and the second extension line (14A) are connected to one another via a hydraulic flow divider (80), so that a volume flow supplied to the at least one front-side support cylinder (60A, 60B) and to the at least one rear-side support cylinder (60C, 60D) or discharged from the support cylinders (60A, 60B, 60C, 60D) is approximately identical, preferably with the following additional feature: d. the hydraulic flow divider (80) is assigned a bypass line (82) and a control valve (84) for controlling the inflow to the hydraulic flow divider (80) and the bypass line (82).

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