Steering systems for vehicles, especially commercial vehicles

Abstract

The present invention relates to an electrohydraulic steering system (100) for a vehicle, particularly a commercial vehicle, comprising: - at least one steering gear (102), particularly a spindle-type steering gear; - at least one first hydraulic, particularly electrohydraulic assembly (106) to which working fluid can be supplied and / or controlled to the steering gear (102); - at least one second hydraulic, particularly electrohydraulic assembly (108) connectable to the steering gear (102); and - at least one captureable assembly of the first and / or second hydraulic assemblies (106, 108). The present invention relates to an electrohydraulic steering system (100) for a vehicle, comprising at least one operating parameter capture device (113) for capturing bri operating parameters, and at least one operating parameter determination device (115), wherein the operating parameter determination device (115) is configured and / or tuned to determine and / or estimate at least one further assembly operating parameter of a first and / or second hydraulic assembly (106, 108) in the form of a determinable assembly operating parameter, based on at least one captureable assembly operating parameter. Furthermore, the present invention relates to a vehicle, in particular a commercial vehicle, having the steering system described above.

Description

Technical Field

[0001] The present invention relates to a vehicle, particularly an electrohydraulic steering system for commercial vehicles. Furthermore, the present invention relates to a vehicle equipped with such an electrohydraulic steering system.

[0002] In conventional steering systems for commercial vehicles, a complex system is created by hydraulic elements or components such as sensors, filters, valves, and / or control elements such as actuators in the form of a steering gear, and such a system has a negative impact on system efficiency and system reliability. In the prior art, steering systems for vehicles, particularly for commercial vehicles, are already known.

[0003] Furthermore, British Patent Application Publication No. 2383433 shows a hydraulic discharge device, such as a power steering pump, having a flow control valve between a pump and a feed and return pipeline. This valve includes a valve piston having a perforated and constricted protrusion, and this valve piston is shiftable against the preloading force of a valve spring for opening a discharge chamber for reflux. The spring is supported between the valve piston and a perforated and constricted setting piston within an integral or multi-piece valve housing, and the preloading force of the spring can be changed via the setting piston.

[0004] The object of the present invention is to develop an electrohydraulic steering system of the type described at the beginning in an advantageous manner, and in particular to develop this system such that it is configured more simply and more efficiently, and is less costly and less prone to failure.

[0005] This object is solved according to the present invention by an electrohydraulic steering system having the features of claim 1. According to this, an electrohydraulic steering system for a vehicle, particularly for a commercial vehicle, comprising: - at least one steering gear, particularly a spindle-type steering gear, and - A steering gear with at least one first hydraulic, in particular electro-hydraulic assembly capable of supplying and / or controlling working fluid, - At least one second hydraulic, in particular electro-hydraulic assembly that can be connected to the steering gear, - At least one operating parameter capture device for capturing at least one captureable assembly operating parameter of a first and / or second hydraulic assembly, - comprising at least one operating parameter determination device, Herein, it is envisioned that an electrohydraulic steering system for a vehicle is provided, wherein the operating parameter determination device is configured and / or tuned to determine and / or estimate at least one further assembly operating parameter of a first and / or second hydraulic assembly in the form of a determinable assembly operating parameter, based on at least one captureable assembly operating parameter.

[0006] The present invention is based on the following fundamental consideration: that an operating parameter determination device is provided, and by using this device, it is possible to determine and estimate the operating parameters of a first and / or second hydraulic assembly by processing, for example, captureable operating parameters transmitted to it by an operating parameter capture device as input variables. This determination or estimation has the advantage that the operating parameter capture device can be constructed more simply because fewer assembly operating parameters need to be captured by actual sensors, since the operating parameter capture device has fewer corresponding sensors or is connected to fewer sensors. This results in a further advantage in that, overall, the number of components in the steering system is reduced, and while the system is error-sensitive and less complex, all important or critical assembly operating parameters (pressure, temperature, valve switching status, etc.) can still be determined. Captureable assembly operating parameters can be understood to mean, in particular, assembly operating parameters that can actually be directly captured using the corresponding sensor device, in which case the sensor device may be a component of the operating parameter capture device or may be connected to it. Accordingly, the decidable assembly operating parameters can be understood to mean, in particular, assembly operating parameters that can be determined or estimated using an operating parameter determination device, in which case one or more captureable assembly operating parameters are available as input variables, and subsequently, decidable assembly operating parameters based on those input variables are correspondingly decidable or estimated. The first and second hydraulic assemblies can also be understood as separate assemblies, in which case they differ at least in function and / or in structural components. The steering gear may further be a component of the first or second hydraulic assembly.

[0007] In addition, it may be assumed that the first hydraulic assembly has at least one hydraulic pump and at least one electric motor for driving the hydraulic pump, and that the operating parameter capture device is configured and / or tuned to capture at least one motor operating parameter of the electric motor and / or at least one pump operating parameter of the hydraulic pump, and that the operating parameter determination device is configured and / or tuned to determine and / or estimate at least one decidable assembly operating parameter of the first and / or second hydraulic assembly based on at least the captured motor operating parameter and / or pump operating parameter. Capturing the assembly operating parameters is advantageous because it can be carried out relatively easily and efficiently. In addition, capturing certain motor operating parameters is advantageous because they may have high predictive power with respect to other assembly operating parameters. This also applies to pump operating parameters. The motor operating parameters and pump operating parameters may be specific operating parameters of the first hydraulic assembly.

[0008] One or more motor operating parameters may include at least one electrical motor current and / or at least one electrical motor voltage and / or at least one motor speed and / or at least one motor output and / or at least one motor torque. Capturing these parameters is advantageous because they may have high predictive power with respect to other, in particular, determinable assembly operating parameters of the first and / or second hydraulic assembly.

[0009] Furthermore, one or more pump operating parameters may include the volumetric flow rate of at least one working fluid and / or the mass flow rate of at least one working fluid and / or at least one pump rotational speed. Capturing these or any of these parameters is also advantageous, as these pump operating parameters may also have high predictive power with respect to other, particularly determinable, assembly operating parameters of the first and / or second hydraulic assembly. The working fluid may be configured as a hydraulic fluid suitable for steering gears.

[0010] Furthermore, one or more captureable assembly operating parameters may include at least one temperature of the working fluid in the first hydraulic assembly and / or at least one pressure of the working fluid in the first hydraulic assembly. For system safety, knowledge of the pressure in the first hydraulic assembly may be particularly advantageous because, if pressure generation occurs in this assembly, this pressure becomes a critical system variable. Based on this knowledge, the operation of the first hydraulic assembly can be monitored with high reliability, making the capture of this operating parameter particularly advantageous, and this also applies to the capture of the working fluid temperature. Temperature capture may also be particularly advantageous because it forms the basis for determining or estimating many further determinable assembly operating parameters, and thus, temperature capture may similarly enable high predictivity for other particularly determinable assembly operating parameters of the first and / or second hydraulic assembly.

[0011] One or more captureable assembly operating parameters may include at least one temperature of the working fluid in the second hydraulic assembly and / or at least one pressure of the working fluid in the second hydraulic assembly. Knowledge of the pressure in the second hydraulic assembly may also be advantageous for system safety, because critical components of the system may be located within this assembly. Capturing this operating parameter may be particularly advantageous because, based on that knowledge, the operation of the second hydraulic assembly can be monitored with high reliability, and this also applies to capturing the temperature of the working fluid. Temperature capture is also particularly advantageous because it forms the basis for determining or estimating many further determinable assembly operating parameters, and thus, temperature capture also enables high predictability of other, particularly determinable assembly operating parameters of the first and / or second hydraulic assembly.

[0012] Furthermore, it may be advantageous that one or more decidable assembly operating parameters include at least one pressure of the working fluid in the second hydraulic assembly. Advantageously, since the pressure of the working fluid in the second hydraulic assembly can be determined or estimated as described above, sensor-based capture of the working fluid pressure in the second hydraulic assembly can be omitted, thereby eliminating components such as sensors and corresponding piping. Thus, the complexity or number of components of the system is reduced, and in this case, the pressure in the second hydraulic assembly is predictable even though it is not actually captured directly.

[0013] The second hydraulic assembly may be configured as a backup assembly and may have at least one hydraulic filter element and at least one backup switching valve. On the one hand, the backup assembly can ensure the steerability of the steering system even in the event of a complete failure of the first hydraulic assembly. This is because the backup assembly causes a short-circuit switching between the two working chambers of the steering gear, thereby allowing the working fluid to move between the two working chambers, which further ensures steering capability. Integrating the hydraulic filter element into the backup assembly is further advantageous in that it allows additional functionality to be occupied by the existing infrastructure of the second hydraulic assembly. This allows for very efficient cleaning of the working fluid (as a hydraulic fluid specialized or suitable for the steering gear) through the second hydraulic assembly by opening the backup switching valve during the non-operational phase of the steering system. This pressurizes the second assembly via the steering gear interposed from the first assembly, thereby making the working fluid filterable. This configuration is particularly advantageous. This is because the steering system can take advantage of the fact that there are always recurring non-operational phases in which steering assistance is not required through operation via the steering gear. However, given the steering assistance that is invoked again at every point (especially during manual steering movements), the hydraulic pump of the first hydraulic assembly should be kept in constant operation mode, and this operation mode can be additionally used for filtration. This eliminates the need for an additional flushing valve or flushing pump, thereby making the steering system simpler, lighter, and less expensive to construct. Alternatively, it may be assumed that the steering gear is not connected or mounted between the first and second assemblies, and that the first and second assemblies are correspondingly directly connected to or fixed to each other, and fixed to the steering gear as a whole assembly.

[0014] One or more decidable assembly operating parameters may include at least one input and / or output pressure of the working fluid in the hydraulic filter element. Monitoring the input and / or output pressures in the hydraulic filter element is important because knowledge of this pressure allows for accurate predictions about the operating state of the hydraulic filter element. Therefore, this pressure is a critical variable of the system that should be monitored. Determining or estimating the input and / or output pressures of the working fluid in the hydraulic filter element may allow for the elimination of pressure sensors (e.g., in the form of differential pressure sensors), which may enable the construction of a second assembly more easily and reliably.

[0015] The operating parameter determination device may be configured and / or tuned to determine and / or estimate at least one input and / or output pressure in a hydraulic filter element based on at least an electrical motor current, the volumetric flow rate of the working fluid, and the temperature of the working fluid, and in particular the pump speed and / or motor speed. In particular, the electrical motor current, the volumetric flow rate of the working fluid, and the temperature of the working fluid are fundamental parameters for measuring or estimating the input and / or output pressure in a hydraulic filter element, and therefore providing them is particularly advantageous. The volumetric flow rate of the working fluid, in particular, is preferably an operating parameter that is determined or derived based on a measured pump speed rather than being captured or measured.

[0016] Furthermore, it is assumed that the operating parameter determination device is configured and / or tuned to determine and / or estimate the filter operating state of the hydraulic filter element, particularly the wear or load state, based at least on the input and / or output pressures of the hydraulic filter element. Monitoring the filter state is crucial for the functionality of the steering system, as this functionality directly affects the system safety of the steering system and, consequently, represents critical system variables. Determining or estimating the input and / or output pressures of the hydraulic filter element provides a very simple and advantageous means, because knowledge of these pressures makes it possible to make highly reliable yet easily implementable predictions about the operating state of the hydraulic filter element. Particularly advantageous is the ability to determine or estimate the input pressure of the hydraulic filter element.

[0017] Furthermore, it is conceivable that a parameter model is implemented in the motion parameter determination device, and that the device is configured and / or tuned to use this parameter model to determine and / or estimate at least one assembly motion parameter of the first and / or second hydraulic assembly based on captureable motion parameters as input variables. Using this parameter model may enable a further improved, more accurate, and more flexible determination or estimation of at least one assembly motion parameter of the first and / or second hydraulic assembly, because the parameter model can be flexibly adapted to the boundary conditions of the steering system.

[0018] Furthermore, it can be assumed that the parameter model implements wiring diagram data assigned to the hydraulic switching configuration of the components and piping of the first and second hydraulic assemblies. By using the wiring diagram data, it is possible to make an improved, more accurate, and more flexible determination or estimation of at least one decidable assembly operating parameter of the first and / or second hydraulic assemblies, because the wiring diagram data allows for a more detailed modeling of the boundary conditions of the steering system.

[0019] Furthermore, the present invention envisions a vehicle, particularly a commercial vehicle, equipped with at least one electrohydraulic steering system as described above. All advantages and technical effects that can be obtained in relation to the steering system according to the present invention can be applied to the vehicle according to the present invention, individually or in combination. This vehicle may be a commercial vehicle in particular.

[0020] Further details and advantages of the present invention will be described in more detail here based on the embodiments shown in the drawings. [Brief explanation of the drawing]

[0021] [Figure 1] This is a schematic diagram showing the switching arrangement configuration of one embodiment of the steering system according to the present invention.

[0022] Figure 1 shows a schematic diagram of the switching arrangement configuration of one embodiment of the steering system 100 according to the present invention.

[0023] The electric hydraulic steering system 100 for commercial vehicles has a steering gear 102 in the form of a spindle-type steering gear 102, which also has a steering gear housing 104.

[0024] The spindle-type steering gear 102 may be configured as a ball-circulating spindle-type steering gear, in which case other gear types are also possible.

[0025] The electro-hydraulic steering system 100 further includes a first hydraulic assembly 106, and this first hydraulic assembly 106 is fixed to the steering gear housing 104.

[0026] The first hydraulic assembly 106 is configured in the form of an electro-hydraulic assembly 106.

[0027] Also, the electro-hydraulic steering system 100 has a second hydraulic assembly 108 fixed to the steering gear housing 104.

[0028] The second hydraulic assembly 108 is configured as an electro-hydraulic assembly 108.

[0029] Fixing the first and second hydraulic assemblies 106, 108 to the steering gear housing 104 can be achieved through corresponding flange joints, but this flange joint is not shown in the schematic diagram of FIG. 1.

[0030] A plurality of components of the first hydraulic assembly 106 may be at least partially integrated within a first housing block 110 (made of the entire block material as the output side structure).

[0031] Correspondingly, a plurality of components of the second hydraulic assembly 108 may also be at least partially integrated within a second housing block 112 (made of the entire block material as the output side structure).

[0032] However, alternatively, it is also conceivable that the first hydraulic assembly 106 and the second hydraulic assembly 108 may be integrated within the first and second assembly housings, respectively.

[0033] The first and second housing blocks 110 and 112 may be structurally separate blocks as shown in Figure 1, and may be fixed to various points on the steering gear housing 104.

[0034] For example, the first and second housing blocks 110 and 112 may be fixed in the steering gear housing 104 at opposing locations (i.e., oriented 180° apart from each other).

[0035] Similarly, the first and second housing blocks 110 and 112 may be fixed in the steering gear housing 104 at an orientation of 90° or 270° relative to each other.

[0036] According to the alternative configuration of the housing block for the steering system 100, one or more components of the first hydraulic assembly 106 and the second hydraulic assembly 108 (not shown in Figure 1) can also be integrated, at least partially, into a single common housing block.

[0037] A common housing block may have a first housing block 110 and a second housing block 112, or may consist of these two housing blocks 110, 112, or alternatively, may be configured as a single housing block (consisting of the entire block material as the starting structure).

[0038] However, alternatively, the first hydraulic assembly 106 and the second hydraulic assembly 108 may each be integrated within a single common assembly housing.

[0039] The steering system 100 further includes an operating parameter capture device 113 for capturing one or more captureable assembly operating parameters of the first and second hydraulic assemblies 106, 108.

[0040] In addition, the steering system 100 has an electronic open-loop control and / or closed-loop control device 114 for open-loop control and / or closed-loop control of the first and second hydraulic assemblies 106, 108.

[0041] Furthermore, the steering system 100 includes an operating parameter determination device 115.

[0042] These devices 113, 114, and 115 are shown in Figure 1 without connecting conduits, in which case these devices 113, 114, and 115 may or may be connected to the corresponding components of the first and second hydraulic assemblies 106 and 108 via connecting conduits.

[0043] Furthermore, it is conceivable that the operation parameter acquisition device 113 and the operation parameter determination device 115 could be integrated into a single common device.

[0044] Alternatively, the operating parameter acquisition device 113 and / or operating parameter determination device 115 may be assumed to be components of an electronic open-loop control and / or closed-loop control device 114.

[0045] As a component, the first hydraulic assembly 106 includes a hydraulic pump 116 and an electric motor M for driving the hydraulic pump 116.

[0046] The hydraulic pump 116 is configured as a double-acting or bidirectional hydraulic pump having a first and a second discharge direction.

[0047] Alternatively, a single, simple-to-operate hydraulic pump may be provided, connected to the first and second pipelines 118, 120 via appropriate switching valves (not shown in Figure 1), and depending on the switching logic, the hydraulic pump 116 may be connected to either the first or second pipeline 118, 120.

[0048] Alternatively, two hydraulic pumps may be provided, in which case each pump may be assigned to or connected to either the first or second pipeline 118,120.

[0049] The first hydraulic assembly 106 further includes a first conduit 118 connected to a first working chamber 122 of the steering gear housing 104.

[0050] The first hydraulic assembly 106 also includes a second conduit 120 connected to a second working chamber 124 of the steering gear housing 104.

[0051] As can be seen in Figure 1, the hydraulic pump 116 is connected to the first pipeline 118 and the second pipeline 120.

[0052] Therefore, the first conduit 118 extends from the first pressure output side of the hydraulic pump 116 to the port of the steering gear housing 104 that opens into the first working chamber 122.

[0053] The second conduit 120 extends accordingly from the second pressure output side of the hydraulic pump 116 to a port in the steering gear housing 104 that opens into the second working chamber 124.

[0054] One hydraulic filter element may be placed in each of the first pipeline 118 and the second pipeline 120.

[0055] Furthermore, as shown in Figure 1, a pressure sensor is located within the first pipeline 118.

[0056] Furthermore, a pressure sensor and a temperature sensor are located inside the second pipeline 120.

[0057] Additionally or alternatively, a temperature sensor may be located within the first conduit 118.

[0058] The first hydraulic assembly 106 may further have a hydraulic tank that is fully or partially integrated within the first housing block 110.

[0059] Alternatively, the hydraulic tank may be flange-fixed to the first housing block 110.

[0060] The hydraulic tank is only shown schematically based on Figure 1, and therefore it is possible that the hydraulic pump 116 is integrated into the tank.

[0061] Alternatively or additionally, the electric motor, hydraulic tank, and hydraulic pump 116 may be flange-fixed to each other and connected via appropriate piping (not shown in Figure 1).

[0062] The hydraulic tank is further equipped with pressure and temperature sensors to monitor the pressure and temperature of the hydraulic fluid inside the tank.

[0063] The second hydraulic assembly 108 is configured as a backup assembly and is connected to the steering gear 102 in the event of an error in the steering system 100.

[0064] Alternatively or additionally, the second hydraulic assembly 108 may be connected to the steering gear 102 in the form of a hydraulic flow connection when the steering system 100 is not in operation.

[0065] The term "connected" here can be understood to mean that a continuous flow path is provided between the steering gear working chambers 122 and 124 via the second hydraulic assembly 108.

[0066] The second hydraulic assembly 108 has, among other components, a hydraulic filter element 126 and a backup switching valve 128.

[0067] The hydraulic filter element 126 and the backup switching valve 128 form a single series circuit.

[0068] In this case, the hydraulic filter element 126 is located upstream of the backup switching valve 128.

[0069] A pressure sensor 144 for monitoring the filter state and a bypass check valve or filter check valve 146 may be arranged in parallel with the hydraulic filter element 126, and in this case, this arrangement configuration may be provided simply at the discretion of the provider.

[0070] The pressure sensor may be configured as a differential pressure sensor, or alternatively, as two separate pressure sensors or pressure switches having configurable pressure trigger thresholds.

[0071] The aforementioned pressure sensor and temperature sensor of the first hydraulic assembly 106, and the pressure sensor 144 of the second hydraulic assembly 108, may be components of the operating parameter acquisition device 113, or may be connected to the operating parameter acquisition device 113 via a corresponding signal conduit.

[0072] The aforementioned pressure sensor 144 and electric motor M are further connected to the electronic open-loop control and / or closed-loop control device 114 via corresponding conduits.

[0073] In addition, the second hydraulic assembly 108 has a further first conduit 130 and a further second conduit 132.

[0074] A further first conduit 130 is connected to the first working chamber 122 of the steering gear housing 104.

[0075] Accordingly, a further second conduit 132 is connected to a second working chamber 124 of the steering gear housing 104.

[0076] As shown in Figure 1, the backup switching valve 128 is switched to the pass-through position when it is inactive or in an error state.

[0077] Therefore, the first work chamber 122 and the second work chamber 124 are connected via further first and further second conduits 130, 132, as well as via the hydraulic filter element 126 and the backup switching valve 128.

[0078] Furthermore, the second hydraulic assembly 108, as shown in Figure 1, comprises a bridge circuit 134 having four external branches 136 and one bridge branch 138, in which case the four external branches 136 are interconnected via four external nodes 140.

[0079] The bridge branch 138 is also composed of a series circuit comprising a hydraulic filter element 126 and a backup switching valve 128.

[0080] Therefore, the first work chamber 122 and the second work chamber 124 are connected to each other via further first and further second conduits 130, 132, and via the bridge circuit 134.

[0081] For this purpose, the bridge circuit 134 is connected to a further first conduit 130 and a further second conduit 132 using two external nodes 140.

[0082] The bridge branch 138 is also connected to two further external nodes 140 of the bridge circuit, which are not connected to the further first and second conduits 130, 132.

[0083] Further first and further second pipelines 130 and 132 may each contain one additional hydraulic filter element.

[0084] The backup switching valve 128 is configured as a 2-port, 2-way solenoid valve and has a switching plunger and an electromagnetic coil for operating the switching plunger. In this case, a change in the switching position of the switching plunger triggers an induced voltage in the electromagnetic coil.

[0085] Furthermore, according to the present invention, a commercial vehicle is envisioned that is equipped with the electro-hydraulic steering system 100 described above (although not shown in Figure 1).

[0086] The functions of the steering system 100 according to the present invention can be described as follows.

[0087] First, the functions of the operation parameter acquisition device 113 and the operation parameter determination device 115 are as follows:

[0088] According to a fundamental consideration of the present invention, the operating parameter determination device 115 is configured and / or tuned to determine and / or estimate at least one further assembly operating parameter of the first and / or second hydraulic assemblies 106, 108 in the form of a determinable assembly operating parameter, based on at least one captureable assembly operating parameter.

[0089] Captureable assembly operation parameters are, in particular, operation parameters that can be captured by sensors or using operation parameter capture devices.

[0090] One or more captureable assembly operating parameters include the temperature of the working fluid in the first hydraulic assembly 106 and / or the pressure of the working fluid within the first hydraulic assembly 106.

[0091] Alternatively, one or more captureable assembly operating parameters may include the temperature of the working fluid in the second hydraulic assembly 108 and / or the pressure of the working fluid within the second hydraulic assembly 108.

[0092] Accordingly, the decidable assembly operation parameters are those that can be determined or estimated based on one or more captureable (and therefore usable as input variables) assembly operation parameters of an operation parameter determination device.

[0093] The determinable assembly operating parameters include the pressure of the working fluid within the second hydraulic assembly 108.

[0094] Preferably, the determinable assembly operating parameters include the input pressure of the working fluid in the hydraulic filter element 126.

[0095] Alternatively or additionally, a determinable assembly operating parameter includes the output side pressure of the working fluid in the hydraulic filter element 126.

[0096] Alternatively or additionally, the determinable assembly operating parameters include the input and output pressures of the working fluid in the hydraulic filter element 126.

[0097] Furthermore, the operating parameter capture device 113 is configured and / or adjusted to capture the motor operating parameters of the electric motor M and / or the pump operating parameters of the hydraulic pump 116.

[0098] One or more motor operating parameters may include an electrical motor current and / or an electrical motor voltage and / or a motor speed and / or at least one motor output and / or at least one motor torque.

[0099] Accordingly, one or more pump operating parameters may include the volumetric flow rate of the working fluid and / or the mass flow rate of the working fluid and / or the pump rotational speed.

[0100] The operating parameter determination device 115 can also determine the electrical motor output by multiplying the electrical motor current and electrical motor voltage or motor torque by the motor rotation speed or motor angular velocity.

[0101] Furthermore, the operating parameter determination device 115 is also configured and / or tuned to determine and / or estimate decidable assembly operating parameters of the first and / or second hydraulic assemblies 106, 108 based on captured motor operating parameters and / or pump operating parameters.

[0102] Specifically, the operating parameter determination device 115 is configured and / or tuned to determine and / or estimate the input pressure in the hydraulic filter element 126 based on the electrical motor current, the volumetric flow rate of the working fluid, and the temperature of the working fluid.

[0103] Alternatively, the operating parameter determination device 115 may be configured and / or tuned to determine and / or estimate the input and output pressures in the hydraulic filter element based on the electrical motor current, the volumetric flow of the working fluid, and the temperature of the working fluid.

[0104] The operating parameter determination device 115 is further configured and / or adjusted to determine and / or estimate the filter operating state of the hydraulic filter element 126 in the form of a worn state or a loaded state, based on the input pressure at the hydraulic filter element 126.

[0105] Alternatively, the operating parameter determination device 115 may be further configured and / or adjusted to determine and / or estimate the filter operating state of the hydraulic filter element 126 in the form of a worn state or a loaded state, based on the input pressure and output pressure at the hydraulic filter element 126.

[0106] Furthermore, the operating parameter determination device 115 is equipped with a parameter model, and using this parameter model, the operating parameter determination device 115 is configured and / or tuned to determine and / or estimate the corresponding assembly operating parameters of the second hydraulic assembly 108 based on one or more captureable operating parameters as described above, as input variables.

[0107] The parameter model includes wiring diagram data, and in this case, the circuit diagram layout configuration shown in Figure 1 may be implemented as described above.

[0108] Accordingly, the wiring diagram data is assigned to the hydraulic switching arrangement configuration of the components and conduits of the first hydraulic assembly 106 and the second hydraulic assembly 108 as shown in Figure 1, and this wiring diagram data is stored in the operating parameter determination device 115 based on the digital wiring diagram model.

[0109] Here, the functions of the operating parameter acquisition device 113 and the operating parameter determination device 115 related to the hydraulic switching arrangement configuration shown in Figure 1 are as follows.

[0110] The hydraulic pump 116 can supply hydraulic fluid to the steering gear 102.

[0111] Furthermore, the steering gear 102 can be controlled by the hydraulic pump 116 based on its various discharge directions.

[0112] More precisely, the first working chamber 122 is supplied with and controllable working fluid by the first conduit 118, because the first conduit connects the working chamber 122 to the hydraulic pump 116.

[0113] Accordingly, the second working chamber 124 can be supplied with and controlled by the second pipeline 120, because the second pipeline connects the working chamber 124 to the hydraulic pump 116.

[0114] This control is achieved by pressurizing either the first working chamber 122 or the second working chamber 124 of the steering gear by the hydraulic pump 116 (but not both simultaneously).

[0115] Therefore, the hydraulic pump 116 is configured such that the first pipeline 118 is pressurized according to the first discharge direction and the second pipeline 120 is pressurized according to the second discharge direction.

[0116] As soon as the hydraulic pump 116 is driven by the electric motor M (for example, clockwise), the hydraulic pump 116 pressurizes the first pipeline 118, which extends to the first working chamber 122, according to the first discharge direction.

[0117] Therefore, the hydraulic pump 116 and the steering gear 102 are interconnected via a first conduit 118, and the port of the steering gear 102, which is connected to the first conduit 118 and opens into the first work chamber 122, is pressurized.

[0118] Accordingly, the pressure increases in the first working chamber 122, forcing the piston to shift linearly. This is because a lower pressure prevails in the opposing second working chamber 124, thereby achieving steering assistance.

[0119] Therefore, the pressure in the opposing second working chamber 124 is lower because this working chamber 124 is connected to the tank via the second pipeline 120 and (not shown in Figure 1) a corresponding return pipeline.

[0120] Therefore, the hydraulic fluid can flow back into the tank from the second working chamber 124.

[0121] In this regard, it is important to understand that the hydraulic pump 116 is always driven in only one direction of rotation, and therefore only the first or second pipeline 118, 120 can always be pressurized.

[0122] When the rotation direction of the hydraulic pump 130 is reversed, the above-described relationships or cases proceed in exactly the reverse order, as will be explained below.

[0123] As soon as the hydraulic pump 116 is driven by the electric motor M (for example, counterclockwise), the hydraulic pump 116 pressurizes the second pipeline 120, which extends to the second working chamber 124, according to the second discharge direction.

[0124] Therefore, the hydraulic pump 116 and the steering gear 102 are interconnected via a second conduit 120, and the port of the steering gear 102, which is connected to the second conduit 120 and opens into the second work chamber 124, is pressurized.

[0125] Accordingly, the pressure in the second working chamber 124 increases, forcing the piston to make a linear shift movement. This is because a lower pressure prevails in the opposing first working chamber 122, thereby achieving steering assistance.

[0126] Therefore, the pressure in the opposing first working chamber 122 is lower because this working chamber 122 is connected to the tank via the first pipeline 118 and (not shown in Figure 1) a corresponding return pipeline.

[0127] Therefore, the hydraulic fluid can flow back into the tank from the first working chamber 122.

[0128] In this regard, it is important to understand that the hydraulic pump 116 is always driven in only one direction of rotation, and therefore only the first or second pipeline 118, 120 can always be pressurized.

[0129] The functions of the steering system 100 described above are explained according to the normal operating state, while the following function descriptions describe the system's non-operational or error state.

[0130] In this state, the backup switching valve 128 is positioned in the flow switching position shown in Figure 1.

[0131] This position allows for uninterrupted flow from the first work chamber 122 to the second work chamber 124 via further first and second conduits 130, 132 and bridge circuit 134.

[0132] The direction of flow of the hydraulic fluid depends on the pressure gradient between the first working chamber 122 and the second working chamber 124.

[0133] A pressure gradient can only be created by the manual steering movement of the steering shaft. This is because the steering shaft takes into account the linear shift movement of the steering gear piston (in this case, no pressurization by the hydraulic pump 116 occurs), and in this case, this case is assigned to an error state.

[0134] Additionally or alternatively, a pressure gradient can be formed by selective pressurization of the first or second working chambers 122,124 by the hydraulic pump 116, as described above, in which case this case is assigned to the steering system non-operating state.

[0135] Non-operational status refers to a state where the steering system is not functioning, that is, a state in which the commercial vehicle is not currently moving or a state in which the commercial vehicle is moving but will not require steering assistance in the future in terms of time series.

[0136] In this case, the operation parameter acquisition device 113 can acquire the corresponding operation parameters of the first and second assemblies 106 and 108, as described above, and transmit them to the operation parameter determination device.

[0137] In particular, the operating parameter determination device 115 can determine or estimate the input pressure at the hydraulic filter element 126 from the captured operating parameters, and from there it can determine the wear state, clogging state, or load state of the hydraulic filter element 126.

[0138] If the pressure inside the first working chamber 122 is higher than that inside the second working chamber 124, then, based on that, in the following flow path or the following components: - A further first pipeline 130 (and possibly a hydraulic filter within the pipeline), - External node 140 connecting bridge circuit 134 and further first conduit 130, - An external branch 136 that is permeable in the direction of flow (uniquely determined by the arrangement of the check valve), -Bridge branch 138, -A further external branch 136, which is permeable in the direction of flow, connects a bridge branch 138 to an external node 140 connected to a second conduit 132, -A further second conduit 132, and - Second work chamber 124 A flow of hydraulic fluid occurs through this passage.

[0139] If the pressure inside the second working chamber 124 is higher than that inside the first working chamber 122, then, based on that, the following flow path or the following components: - A further second pipeline 132 (and possibly a hydraulic filter within that pipeline), - External node 140 connecting bridge circuit 134 to a further second conduit 132, - An external branch 136 that is permeable in the direction of flow (uniquely determined by the arrangement of the check valve), -Bridge branch 138, -A further external branch 136, which is permeable in the direction of flow, connects a bridge branch 138 to an external node 140 connected to a further first conduit 130, - Further first conduit 130, and - First working chamber 122 A flow of hydraulic fluid occurs through this passage.

[0140] The two flow paths described above enable the cleaning of the hydraulic fluid via the hydraulic filter element 126, which is the main filter element.

[0141] To that extent, the hydraulic fluid can be cleaned very efficiently when the steering system is not in operation, because the pressure required for this is far less than that required for steering assistance.

[0142] This is because these pressures must remain below a certain pressure threshold, so as not to result in an operation that would cause the steering gear piston to trigger actual steering movement or steering assistance.

[0143] However, based on the friction and inertia in the steering system, cleaning below the aforementioned pressure threshold is quite possible, so highly efficient cleaning via the hydraulic filter element 126 will be possible when the steering system 100 is not in operation. [Explanation of Symbols]

[0144] 100 Electro-hydraulic steering system 102 Steering gears, especially spindle-type steering gears 104 Steering gear housing 106 First hydraulic assembly, in particular electro-hydraulic assembly 108 Second hydraulic, especially electro-hydraulic assembly 110 First Housing Block 112 Second Housing Block 113 Operating parameter acquisition device 114 Electronic open-loop control and / or closed-loop control device 115 Operating parameter determination device 116 Hydraulic pump 118 First pipeline 120 Second pipeline 122 First working chamber 124 Second working chamber 126 Hydraulic filter element 128 Backup switching valve 130 Further First Pipeline 132 A second pipeline 134 Bridge Circuit 136 External branch 138 Bridge Branch 140 external nodes 142 Check valve 144 Pressure Sensor 146 Filter Check Valve M Electric Motor

Claims

1. An electro-hydraulic steering system (100) for vehicles, particularly commercial vehicles, the following: At least one steering gear (102), in particular a spindle-type steering gear, The steering gear (102) is supplied with and / or controlled by at least one first hydraulic, in particular electro-hydraulic assembly (106), At least one second hydraulic, in particular electro-hydraulic assembly (108) connectable to the steering gear (102), At least one operating parameter capture device (113) for capturing at least one captureable assembly operating parameter of the first and / or second hydraulic assemblies (106, 108), The system comprises at least one operating parameter determination device (115), An electrohydraulic steering system (100) for a vehicle, wherein the operating parameter determination device (115) is configured and / or tuned to determine and / or estimate at least one further assembly operating parameter of the first and / or second hydraulic assemblies (106, 108) in the form of a determinable assembly operating parameter, based on at least one captureable assembly operating parameter.

2. The first hydraulic assembly (106) includes at least one hydraulic pump (116) and at least one electric motor (M) for driving the hydraulic pump (116), The operation parameter acquisition device (113) is configured and / or adjusted to acquire at least one motor operation parameter of the electric motor (M) and / or at least one pump operation parameter of the hydraulic pump (116). The electrohydraulic steering system (100) according to claim 1, wherein the operating parameter determination device (115) is configured and / or tuned to determine and / or estimate at least one decidable assembly operating parameter of the first and / or second hydraulic assemblies (106, 108) based on at least the captured motor operating parameters and / or the pump operating parameters.

3. The electrohydraulic steering system (100) according to claim 2, wherein one or more motor operating parameters include at least one electrical motor current and / or at least one electrical motor voltage and / or at least one motor speed and / or at least one motor output and / or at least one motor torque.

4. The electrohydraulic steering system (100) according to claim 2 or 3, wherein one or more of the pump operating parameters include a volumetric flow rate of at least one working fluid and / or a mass flow rate of at least one working fluid and / or at least one pump rotation speed.

5. An electrohydraulic steering system (100) according to any one of claims 1 to 4, wherein one or more captureable assembly operating parameters include at least one temperature of the working fluid in the first hydraulic assembly (106) and / or at least one pressure of the working fluid in the first hydraulic assembly (106).

6. The electrohydraulic steering system (100) according to any one of claims 1 to 5, wherein one or more captureable assembly operating parameters include at least one temperature of the working fluid in the second hydraulic assembly (108) and / or at least one pressure of the working fluid in the second hydraulic assembly (108).

7. The electrohydraulic steering system (100) according to any one of claims 1 to 6, wherein one or more determinable assembly operating parameters include the pressure of at least one working fluid in the second hydraulic assembly (108).

8. The electro-hydraulic steering system (100) according to any one of claims 1 to 7, wherein the second hydraulic assembly (108) is configured as a backup assembly and comprises at least one hydraulic filter element (126) and at least one backup switching valve (128).

9. The electrohydraulic steering system (100) according to claim 8, wherein one or more determinable assembly operating parameters include at least one input-side pressure and / or output-side pressure of the working fluid in the hydraulic filter element (126).

10. The electrohydraulic steering system (100) according to claim 8 or 9, wherein the operating parameter determination device (115) is configured and / or tuned to determine and / or estimate at least one input pressure and / or output pressure in the hydraulic filter element based on at least the electrical motor current, the volumetric flow rate of the working fluid, and the temperature of the working fluid, and in particular the pump speed and / or the motor speed.

11. The electrohydraulic steering system (100) according to claim 10, wherein the operating parameter determination device (115) is configured and / or adjusted to determine and / or estimate the filter operating state of the hydraulic filter element (126), particularly the wear state or load state, based on at least the input pressure and / or output pressure of the hydraulic filter element (126).

12. The electrohydraulic steering system (100) according to any one of claims 1 to 11, wherein a parameter model is implemented in the operating parameter determination device (115), and the operating parameter determination device (115) is configured and / or tuned to determine and / or estimate at least one assembly operating parameter of the first and / or second hydraulic assemblies (106, 108) based on captureable operating parameters as input variables, using the parameter model.

13. The parameter model includes wiring diagram data assigned to the hydraulic switching arrangement configuration of the components and piping of the first hydraulic assembly (106) and the second hydraulic assembly (108). The electro-hydraulic steering system (100) according to claim 12.

14. A vehicle, particularly a commercial vehicle, comprising at least one electrohydraulic steering system (100) according to any one of claims 1 to 13.

Images