Steering system

Abstract

The object of the present invention is to provide an efficient and economical possibility for meeting redundancy requirements, preferably with respect to safety and / or power level requirements. [Solution] The present invention relates to a steering system (100) for a commercial vehicle comprising at least one road wheel actuator for applying a steering impulse to at least one road wheel of the vehicle, wherein the at least one road wheel actuator is configured as an assembly comprising at least one first module (110) comprising a hydraulic actuator, at least one second module (120) comprising a hydraulic pump and a valve block, and at least one third module (130) comprising an electric motor and an electronic control unit, wherein the road wheel actuator comprises an additional first module, a second module, and / or a third module.

Description

Technical Field

[0005]

[0001] The present invention relates to a steering system, particularly to a steer-by-wire system and a corresponding road wheel actuator, particularly a modular road wheel actuator.

[0002] According to the prior art, a steering system such as a steer-by-wire system is known from the example of International Publication No. 2022 / 175120, which discloses an electro-hydraulic power steering system for a vehicle comprising, for example, a hydraulic pump, a drive device, a first working line, a second working line, and a heat transfer unit.

[0003] However, in contrast to such known prior art, it may be necessary to provide a certain level of redundancy or different power levels depending on the load or multiple steering axles, as well as depending on the use of the vehicle.

[0004] International Publication No. 2021 / 1163243 discloses a redundant steering system, which comprises a primary power source, a secondary power source, first and second pumps operatively coupled to the primary and secondary power sources respectively and outputting first and second hydraulic fluid supplies to a steering cylinder based on the operation of the primary and secondary power sources, first and second pairs of selector valves coupled to the first and second pumps respectively, and a charging circuit coupled to respective control inputs of the first and second pairs of selector valves to selectively supply hydraulic fluid to the control inputs of the first and second pairs of selector valves to stop the supply of hydraulic fluid to the steering cylinder from only one of the first pump and the second pump and supply hydraulic fluid to the steering cylinder from only the other one of the first pump and the second pump.

[0005] International Publication No. 2004 / 005112 discloses a hydraulic power-assisted steering system comprising a steering gear and hydraulic actuator for assisting the operation of the steering wheel by a driver of a vehicle, in particular an automobile, and comprising an electric motor coupled to the steering column and used as an additional torque actuator for actively applying additional steering torque, and further comprising an electronic control and adjustment unit comprising a determination unit for determining the steering torque and an evaluation and selector circuit used to determine the total value for applying the additional steering torque, the additional steering torque taking into account the determined steering torque, or a variable derived therefrom, and selected steering characteristics. The total value for applying the additional steering torque comprises driver-dependent and driver-independent components.

[0006] International Publication No. 2015 / 003803 discloses an electro-hydraulic steering system, more specifically for mobile work machines, more specifically for wheel loaders, which has at least one controller having at least one hydraulic branch, comprising at least one hydraulic primary circuit and at least one hydraulic secondary circuit, the hydraulic primary circuit comprising at least one main valve for hydraulic operation of the steering system, and the hydraulic secondary circuit comprising at least one emergency valve for hydraulic operation of the steering system in emergency mode, the emergency valve being smaller than the main valve.

[0007] European Patent No. 3967573 discloses a drive-by-wire electro-hydraulic steering system based on a dual-wound motor and a hybrid control method. The steering system comprises a steering wheel, a steering column assembly, a road sensing assembly, an electro-hydraulic power assist module, a dual-wound motor power assist module, a steering control unit, an electromagnetic clutch, a steering tie rod, a steering trapezoid, and a steering wheel. The steering system can switch between various steering operating modes depending on the vehicle's operating conditions to meet steering requirements under various operating conditions, and has a motor winding redundancy function by using an operating mode in which two sets of windings of the dual-wound motor operate simultaneously. If one set of windings fails, the other set of windings can drive the motor and provide power assist torque.

[0008] European Patent No. 1914150 discloses a steering system, particularly a steer-by-wire steering system, comprising a hydraulic circuit including a hydraulic pump, a reservoir, a bidirectional steering actuator, and a pair of electronic control units for generating electric steering control signals in response to steering commands generated by an operator. Such a circuit is needed that does not require large and expensive valves. The hydraulic circuit includes a pair of solenoid-operated directional control valve units and a pair of solenoid-operated shut-off valves. Each directional control valve unit and one corresponding shut-off valve are connected in series between the pump, reservoir, and steering actuator, and are connected to and controlled by the respective ECUs. When no fault condition exists, both shut-off valves are open, and thus the flow of hydraulics to and from the actuators is shared by both the first and second directional control valve units.

[0009] However, each known system only allows for specific redundant components, and none of these systems are scalable to meet varying redundancy requirements.

[0010] An object of the present invention is to provide an efficient and economical possibility for meeting redundancy requirements, preferably with respect to safety and / or power level requirements. A further object is to provide a system that can be easily adapted to different redundancy or power level requirements. Furthermore, an object of the present invention is to provide a corresponding modular load wheel actuator.

[0011] These objectives are addressed by the system described in independent claim 1 and the load wheel actuator described in independent claim 13. Preferred embodiments are addressed by the dependent claims, respectively.

[0012] According to the present invention, a steering system for commercial vehicles, in particular a steer-by-wire system, is provided, which comprises at least one load wheel actuator for acting a steering impulse on at least one load wheel of the vehicle, the at least one load wheel actuator is - A first module comprising at least one hydraulic actuator, such as a hydraulic cylinder, - A second module comprising at least one hydraulic pump and valve block, - It is configured as a modular assembly comprising at least one third module having an electric motor and an electronic control unit, The load wheel actuator further comprises at least one additional first module, a second module, and / or a third module.

[0013] The present invention is based on the idea of ​​providing a modular design for a road wheel actuator, and by extension, the entire steering system, where a single component can be scaled, for example, two or three times, as required.

[0014] Therefore, in the context of the present invention, the steering system can be considered as a modular steering system.

[0015] In particular, the present invention can provide redundancy of components for safety and / or reliability reasons, and the power level of the steering system can be adapted and scaled according to the individual needs of each application.

[0016] According to one preferred embodiment, the load wheel actuator comprises two third modules configured to increase the power of the steering system.

[0017] Therefore, depending on the individual needs of a particular (field of application), steering systems, especially road wheel actuators, can be provided with specially scaled power levels to meet the corresponding requirements.

[0018] According to one preferred embodiment, the load wheel actuator comprises two or three third modules configured to be used, depending on the preconditions, to function as redundant modules or to increase the power of the steering system. Depending on the preconditions, the system may be configured to have the power of two or three additional third modules or to have three redundant third modules.

[0019] According to one preferred embodiment, a second module, in particular an electronic control unit, comprises sensors to enable steering of at least one load wheel and / or to be required for steering of at least one load wheel.

[0020] According to one preferred embodiment, the load wheel actuator includes a sensor to enable steering of at least one load wheel and / or to be required for steering of at least one load wheel, the sensor being located outside the second module.

[0021] According to another preferred embodiment, the load wheel actuator comprises only one third module, and the motor of the third module is provided as a double-wound motor. Such a double-wound module makes it possible to use each winding for a separate motor, particularly to increase the power level.

[0022] In embodiments having two or more third modules, each of the motors may be configured as a redundant motor, preferably in the form of a double-wound motor.

[0023] According to one preferred embodiment, each of the electronic control units located in each third module is connected in a communicative manner to communicate and / or cooperate with one another.

[0024] According to an alternative preferred embodiment, each of the electronic control units located in each third module is connected to each other in a communicative manner, forming a primary-secondary setup also known as a “master-slave” setup.

[0025] According to one preferred embodiment, one of the electronic control units is selectable as the primary control unit for a predetermined first (time) period, thereby at the end of the first period, a different control unit is selectable as the primary control unit for a predetermined second (time) period, and / or the selection of one of the electronic control units as the primary control unit preferably includes a fault-free test, thereby -If no failures are found during the non-fault test, the electronic control unit is selected as the primary. - If a fault is detected during the non-fault test, the electronic control unit will not be selected, and the non-fault test will be performed using a different control unit.

[0026] According to one preferred embodiment, each of the control units is configured to check its operating state and provide information regarding its operating state to other control unit(s).

[0027] Thus, when one of the control units having the primary function communicates, other control unit(s) can automatically switch to the secondary mode.

[0028] When the control unit operating as the primary transmits a failure status, one of the other control unit(s) takes over the primary function.

[0029] Preferably, a predetermined ranking between the control units for taking over the primary role within the primary-secondary combination setup can be established. Thus, a separate order of the control units can be guaranteed regarding the selection of the control unit as primary or secondary.

[0030] In another preferred embodiment, the system further comprises a steering wheel device configured to provide a user input signal to at least one load wheel actuator, and at least one load wheel configured to be actuated by at least one load wheel actuator, particularly according to the user input signal.

[0031] Particularly, the user input signal / command may be provided in a form that rotates the steering wheel device, whereby the rotation may be converted and / or transmitted as a corresponding input signal / command to further components, such as a control unit of a steering system, particularly a steer-by-wire system.

[0032] According to another aspect of the present invention, a road wheel actuator for a steering system described in one of the above claims is provided, in particular a modular road wheel actuator comprising at least one or more modules, a first module, a second module and / or a third module.

[0033] Further details and advantages of the present invention will be described and stated in more detail in relation to embodiments shown in the accompanying drawings. [Brief explanation of the drawing]

[0034] [Figure 1] This figure shows an embodiment of a steering system, particularly a modular steer-by-wire system. [Figure 2] This figure shows another embodiment of a steering system, particularly a modular steer-by-wire system with double the number of motor units. [Figure 3] This figure shows another embodiment of a steering system, in particular another embodiment of a modular steer-by-wire system having three times the number of motor units. [Figure 4] This figure shows another embodiment of a steering system, particularly a modular steer-by-wire system in which all modular components are doubled.

[0035] Figure 1 shows an embodiment of a steering system 100, preferably a steer-by-wire system, comprising a first module 110, a second module 120, and a third module 130.

[0036] The first module 110 includes a hydraulic cylinder, which is configured to actuate at least one load wheel.

[0037] The second module 120 includes a hydraulic pump and valves. The second module is hydraulically connected to the first module.

[0038] The third module 130 comprises an electric motor and an electronic control unit 140. The electric motor is connected to the second module to drive a hydraulic pump.

[0039] Figure 2 shows an alternative embodiment in which the third module 130, which includes an electric motor and an electronic control unit 140, is doubled, i.e., redundantly provided.

[0040] In such embodiments, the third module 130 may be used as a backup or to combine the power of the electric motors of both third modules 130.

[0041] The electronic control units 140 may be connected to each other in a communicative manner, for example, to enable one of the control units 140 to have the function of a primary electronic control unit and the other to have a secondary function.

[0042] Both third modules 130 are connected to the same second module 120.

[0043] In the embodiment shown in Figure 2, the third module 130 is connected to both sides of the second module 120 so that both electric motors can drive the hydraulic pump in the second module 120.

[0044] Figure 3 shows an embodiment that has three third modules instead of two, compared to the embodiment shown in Figure 2.

[0045] In such cases, the third module 130 may be positioned along different sides / side regions of the second module 120.

[0046] Figure 4 shows an embodiment in which the first module 110, the second module 120, and the third module 130 are doubled.

[0047] The first module 110 is arranged in particular side by side so that it can act on the same steered wheel(s), so that it can be made redundant, or so that it can act in parallel to the same steered wheel(s).

[0048] For example, in the case of a redundant arrangement of the first modules, each equipped with a hydraulic cylinder, the power from both first modules 110 can be combined to provide a scaled power level for acting on at least one of the load wheels and applying a steering impulse.

[0049] Each of the first modules 110 is connected to a second module 120, and each of the second modules is connected to a third module 130, which includes an electronic control unit 140.

[0050] As already mentioned with reference to Figure 2, the electronic control units 140 may be connected in a communicative manner to each other in order to determine and / or set one of the electronic control units 140 as the primary ("master") and one or more of the remaining electronic control units as secondary ("slave(s)"), in particular to enable them to exchange information with each other regarding their respective operating status and / or whether they are faulty or not.

[0051] In summary, the present invention makes it possible to establish a modular steering system, in particular a modular steer-by-wire system, and by using different modular configurations, scalable redundancy and / or scalable power levels of different component groups can be provided in a simple and cost-effective manner, and these modular configurations may be arranged and combined taking into account the requirements and needs of their respective (field) applications. [Explanation of Symbols]

[0052] 100 Steering System 110 First module 120 Second module 130 Third Module 140 Electronic control unit

Claims

1. A steering system (100) for a commercial vehicle, comprising at least one road wheel actuator for applying a steering impulse to at least one road wheel of the vehicle, wherein the at least one road wheel actuator is A first module (110) equipped with a hydraulic actuator, A second module (120) comprising a hydraulic pump and a valve block, It comprises at least one third module (130) which includes an electric motor and an electronic control unit, The road wheel actuator further comprises at least one additional first module, a second module, and / or a third module, in a steering system (100).

2. The road wheel actuator comprises two third modules (130) configured to increase the power of the steering system (100). The steering system (100) according to claim 1.

3. The load wheel actuator comprises two or three third modules (130) configured to be used, depending on the preconditions, to function as redundant modules or to increase the power of the steering system. The steering system (100) according to claim 1 or 2.

4. The second module (120), in particular the electronic control unit (140), includes a sensor to enable steering of the at least one road wheel. A steering system (100) according to any one of claims 1 to 3.

5. To enable steering of at least one of the load wheels, the load wheel actuator is equipped with a sensor, the sensor being located outside the second module (120). A steering system (100) according to any one of claims 1 to 3.

6. The load wheel actuator comprises only one third module (130), and the motor of the third module (130) is provided as a double-wound motor. A steering system (100) according to any one of claims 1, 4, and 5.

7. The motors of each third module (130) are preferably provided as redundant motors in the form of double-wound motors. The steering system (100) according to claim 2 or 3.

8. Each of the electronic control units (140) located in each third module (130) is communicated to each other and / or cooperate with each other. A steering system (100) according to any one of claims 1 to 7.

9. Each of the electronic control units (140) located within each third module (130) is connected to each other in a way that enables communication, forming a primary-secondary setup. A steering system (100) according to any one of claims 1 to 8.

10. One of the electronic control units (140) can be selected as the primary control unit for a predetermined first period, and thereafter, at the end of the first period, the other control unit can be selected as the primary control unit for a further predetermined second period. and / or Selecting one of the aforementioned electronic control units (140) as the primary control unit preferably includes a fault-free test, thereby If no failures occur during the aforementioned fault-free test, the electronic control unit is selected as the primary control unit. If the non-fault test results in a fault, the electronic control unit is not selected, and the non-fault test is performed using a different control unit. The steering system (100) according to claim 9.

11. Each of the control units (140) is configured to check its operating state and provide information regarding its operating state to the other control units (140) (multiple units are possible). The steering system (100) according to claim 10.

12. The system further comprises a steering wheel device configured to provide a user input signal to the at least one load wheel actuator, and at least one load wheel configured to be actuated by the at least one load wheel actuator in accordance with the user input signal. The steering system according to any one of claims 1 to 11.

13. A road wheel actuator, more particularly a modular road wheel actuator for a steering system according to any one of claims 1 to 12, comprising a plurality of modules, at least one of the first module (110), the second module (120), and / or the third module (130).

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