DE102023113966A1 - Chassis Device, Vehicle and Method - Google Patents

Abstract

Chassis device (9) for a wheel (5, 6) of a vehicle (1), with a hydraulic cylinder (12) in which hydraulic fluid (20) is accommodated, a gas spring accumulator (25) in which hydraulic fluid (20) is also accommodated, an adjustable damping valve (32) which is in fluid communication with both the hydraulic cylinder (12) and the gas spring accumulator (25), a hydraulic pump (22) which is in fluid communication with both the hydraulic cylinder (12) and the gas spring accumulator (25), and a regulating and control device (44) for continuously opening and closing the damping valve (32) and for switching the hydraulic pump (22) from a pumping mode to a recuperation mode and vice versa, wherein the damping valve (32) and the hydraulic pump (22) are connected in parallel to one another, wherein during driving operation of the chassis device (9) hydraulic fluid (20) is supplied from the hydraulic cylinder (12) to the gas spring accumulator (25) and vice versa through the damping valve (32) and/or through the hydraulic pump (22), and wherein the regulating and control device (44) is designed to increasingly close the damping valve (32) during driving operation in order to increase a volume flow of the hydraulic fluid (20) flowing through the hydraulic pump (22), and to put the hydraulic pump (22) into the recuperation mode, so that an electrical power output by the hydraulic pump (22) during the recuperation mode increases with increasing closing of the damping valve (32).

Description

The present invention relates to a chassis device for a vehicle, a vehicle with such a chassis device and a method for operating such a chassis device.

Semi-active dampers, hydropneumatic springs, air springs and other adjustable chassis components are known in-house to increase the driving comfort and handling of motor vehicles. With the help of such chassis components, for example, a variation in damping behavior to adapt the driving comfort and handling, a variation in spring stiffness to adapt the driving comfort or to balance loads, a variation in vehicle inclination in both a longitudinal and transverse direction to compensate for the vehicle inclination or for dynamic steering in curves, and a variation in vehicle height, both dynamically to compensate for uneven road surfaces and passively to adjust the vehicle height and/or ground clearance, can be achieved. In the case of electric vehicles in particular, it is desirable to increase the achievable range as much as possible. For this purpose, chassis components can be used to generate electrical energy, as previously mentioned.

The DE 10 2019 111 980 A1 accordingly shows a device for providing hydraulic energy, in particular in a chassis system of a vehicle, wherein the device has a first and a second motor-pump unit which are mechanically firmly connected to one another, wherein the two motor-pump units are preferably designed to be identical in construction.

Against this background, an object of the present invention is to provide an improved chassis device.

Accordingly, a chassis device for a wheel of a vehicle is proposed. The chassis device comprises a hydraulic cylinder in which hydraulic fluid is accommodated, a gas spring accumulator in which hydraulic fluid is also accommodated, an adjustable damping valve which is in fluid communication with both the hydraulic cylinder and the gas spring accumulator, a hydraulic pump which is in fluid communication with both the hydraulic cylinder and the gas spring accumulator, and a regulating and control device for continuously opening and closing the damping valve and for switching the hydraulic pump from a pumping mode to a recuperation mode and vice versa, wherein the damping valve and the hydraulic pump are connected in parallel to one another, wherein during driving operation of the chassis device hydraulic fluid flows from the hydraulic cylinder to the gas spring accumulator and vice versa through the damping valve and/or through the hydraulic pump, and wherein the regulating and control device is designed to increasingly close the damping valve during driving operation in order to increase a volume flow of the hydraulic fluid flowing through the hydraulic pump and to switch the hydraulic pump to the recuperation mode so that a pressure output by the hydraulic pump during the recuperation mode electrical power increases with increasing closing of the damping valve.

Because the control device increasingly closes the damping valve during driving and at the same time puts the hydraulic pump into recuperation mode, whereby the electrical power delivered by the hydraulic pump increases, it is possible to increase the range of the preferably electrically powered vehicle.

The chassis device can be part of a chassis of the vehicle. Preferably, each wheel of the vehicle is assigned such a chassis device. In the event that the vehicle has four wheels, it also has in particular four chassis devices. Thus, several, in particular four, chassis devices together with a chassis of the vehicle form a chassis of the vehicle. Each wheel is coupled or operatively connected to the chassis in particular with the aid of the hydraulic cylinder assigned to it.

The chassis devices of different wheels can have common parts or components. For example, all chassis devices can have a common regulating and control device. However, each chassis device can also be assigned its own regulating and control device. The vehicle is particularly preferably an electric vehicle. The terms "vehicle" and "electric vehicle" can therefore be interchanged as desired. However, the vehicle can also be a hybrid vehicle. In this case, the vehicle can have an internal combustion engine.

The hydraulic cylinder preferably comprises a housing in which a piston is accommodated that can be moved into and out of the housing. Between the housing and the piston, a receiving space is preferably provided that can be filled with the hydraulic fluid. The housing is in particular connected to a Connecting element, for example in the form of a ball head, connected to the chassis. Accordingly, the piston can be connected to one of the wheels in particular with the aid of a further connecting element, for example in the form of a ball head. Conversely, the housing can also be coupled to the respective wheel and the piston to the chassis. The hydraulic cylinder preferably has exactly one hydraulic connection. The hydraulic connection is provided in particular on the housing of the hydraulic cylinder. The hydraulic fluid is preferably hydraulic oil.

During driving or while the chassis device or the vehicle is moving, the piston is moved into the housing and out of it again. As a result, the hydraulic fluid held in the hydraulic cylinder is at least partially displaced from the hydraulic cylinder or flows back into it. During driving, the vehicle moves along a surface. The surface can be a road or any type of terrain. The wheels roll on the surface during driving.

The driving operation can include, for example, cornering, driving uphill, driving downhill or the like. During driving, the vehicle can also drive over uneven ground. During driving, hydraulic fluid flows from the hydraulic cylinder to the gas spring accumulator and vice versa, depending on whether the piston moves into or out of the housing. This hydraulic fluid can then flow through the damping valve and/or through the hydraulic pump or be pumped through them.

The gas spring accumulator functions in particular as a suspension for the wheel assigned to the respective chassis device. The hydraulic cylinder, on the other hand, functions as a spring strut for the respective wheel. The gas spring accumulator preferably has a housing in which hydraulic fluid is accommodated. The gas spring accumulator preferably comprises a membrane which separates the hydraulic fluid from a gas accommodated in the housing of the gas spring accumulator. The gas can be nitrogen, for example. The membrane is pre-tensioned with the aid of the gas. If hydraulic fluid is pressed or pumped into the gas spring accumulator, the membrane deforms and the gas is compressed. The gas then exerts pressure on the hydraulic fluid indirectly via the membrane.

The damping valve is preferably a throttle valve and can therefore also be referred to as a throttle valve. The damping valve acts as a throttle provided between the hydraulic cylinder and the gas spring accumulator. The fact that the damping valve is "adjustable" or "configurable" is to be understood in this case in particular to mean that the damping valve can be moved continuously from an open state to a closed state and vice versa. "Continuously" means in particular that the damping valve can be moved to any number of intermediate states between the open state and the closed state. In particular, the damping valve can be opened and closed continuously from 0% to 100%. For this purpose, the damping valve can have an actuator or a control element, for example in the form of an electric motor.

During driving, the damping valve acts in particular as a damper for the wheel assigned to the chassis device. The further the damping valve is opened, the more hydraulic fluid flows through the damping valve during driving and the less hydraulic fluid flows through the hydraulic pump and vice versa. The hydraulic fluid can flow through the damping valve in two directions. The damping valve therefore works bidirectionally or independently of direction. The same applies to the hydraulic pump.

The more hydraulic fluid flows through the damping valve, the "softer" the chassis device or the chassis and the greater the driving comfort. The further the damping valve is closed, the "harder" the chassis device or the chassis and the less comfortable the driving. Driving comfort therefore decreases as the electrical power output of the hydraulic pump increases. In return, however, the range of the vehicle is increased.

The regulating and control device accordingly controls the damping valve and the hydraulic pump in particular in such a way that an optimization is achieved with regard to the possible achievable range of the vehicle. The regulating and control device can thus control or regulate the damping valve and the hydraulic pump in such a way that the greatest possible range or any predetermined range of the vehicle can be achieved.

In particular, the control and regulating device can also control or regulate the damping valve and the hydraulic pump depending on the charge level of an energy storage device of the chassis device or the vehicle. For example, this is done in such a way that a predetermined charge level of the energy storage device is not exceeded during driving. The "state of charge" can be specified in percentage values, with 100% representing a fully charged energy storage device. The energy storage device can be an accumulator.

The fact that the damping valve is "fluidly connected" to both the hydraulic cylinder and the gas spring accumulator means in particular that the damping valve is arranged between the hydraulic cylinder and the gas spring accumulator in such a way that hydraulic fluid can flow or be conveyed from the hydraulic cylinder through the damping valve to the gas spring accumulator or vice versa. However, this does not rule out the possibility that the damping valve can be completely closed so that there is no longer any fluid connection between the hydraulic cylinder and the gas spring accumulator, at least temporarily.

The fact that the hydraulic pump is "fluidly connected" to the hydraulic cylinder and to the gas spring accumulator means in particular that hydraulic fluid can flow or be conveyed from the hydraulic cylinder through the hydraulic pump to the gas spring accumulator or vice versa. However, this does not exclude the possibility that the fluid connection between the hydraulic pump and the hydraulic cylinder or between the hydraulic pump and the gas spring accumulator can be separated at least temporarily. The hydraulic pump is placed in particular between the hydraulic cylinder and the gas spring accumulator.

The hydraulic pump is preferably a servo pump. In particular, the hydraulic pump is an electrohydraulic pump. In particular, the hydraulic pump can be a four-quadrant servo pump. The hydraulic pump has in particular a motor that can function as a generator for generating electrical energy. Because the hydraulic pump is designed in particular to be four-quadrant capable, alternating or alternating operation as an electric drive and/or as an electric generator is possible, whereby, for example, as a result of a pressure surge on the hydraulic pump, for example as a result of a mechanical shock on the wheel and thus on the piston of the hydraulic cylinder, hydraulic energy can be recovered from the chassis device as electrical energy via the hydraulic pump.

In this case, a “recuperative operation”, “recuperation operation” or “recuperation mode” of the hydraulic pump is understood to mean in particular that the hydraulic fluid flows through the hydraulic pump and drives the motor of the hydraulic pump, which then acts as a generator to generate electricity. In this case, rotational energy of a drive shaft of the motor driven by the hydraulic fluid is converted into electrical energy. In contrast to the recuperation mode, a “pumping operation”, “pumping operation” or “pumping mode” of the hydraulic pump is understood to mean that the hydraulic pump, in particular its motor, is driven and conveys or pumps the hydraulic fluid.

For example, switching between the pumping mode of the hydraulic pump and the recuperation mode of the hydraulic pump can be possible with a temporal resolution of up to 50 Hz or more. This enables highly dynamic switching between the pumping mode and the recuperation mode and vice versa. In particular, both the recuperation mode and the pumping mode function bidirectionally. This means that both the recuperation mode and the pumping mode are independent of the direction of flow of the hydraulic fluid through the hydraulic pump.

The regulating and control device can be part of a vehicle control system. The regulating and control device can be, for example, a program stored in a control unit of the vehicle. The regulating and control device is operatively connected to the damping valve and the hydraulic pump in such a way that the regulating and control device can open and close the damping valve and can switch the hydraulic pump from pump mode to recuperation mode and vice versa. The connection between the regulating and control device and the damping valve or the hydraulic pump can be wired or wireless.

Several chassis devices can have a common regulating and control device. The regulating and control device can be set up to receive and evaluate sensor signals from a sensor system and to control and/or regulate the hydraulic pump and the damping valve based on these sensor signals. The sensor system can have a wide variety of sensors. For example, the sensor system can include pressure sensors that are set up to detect a respective hydraulic pressure in the chassis device, the hydraulic cylinder and/or the gas spring accumulator. The sensor system can also be suitable for detecting and/or evaluating the charge state of the energy accumulator.

In particular, a pressure sensor can also be assigned to the hydraulic pump. Several pressure sensors can also be assigned to the hydraulic pump. The sensor system can also include a displacement sensor, which can, for example, detect how far the piston is moved into or out of the housing of the hydraulic cylinder. The sensor system can also have speed sensors, acceleration sensors, inertia sensors and/or temperature sensors. In principle, however, the sensor system can have any type of sensor. The sensor system can also be suitable for detecting and/or evaluating a motor current of the hydraulic pump or the motor of the hydraulic pump.

The fact that the damping valve and the hydraulic pump are connected "parallel" to one another means in particular that the hydraulic fluid can flow through the damping valve and the hydraulic pump at the same time. Depending on whether the damping valve is open or closed, the hydraulic fluid can flow either only through the damping valve, only through the hydraulic pump, or both through the damping valve and the hydraulic pump.

When the damping valve is fully open, preferably no or only a very small volume flow of hydraulic fluid flows through the hydraulic pump. During operation of the chassis device, the hydraulic fluid can then flow from the hydraulic cylinder to the gas spring accumulator and vice versa, either only through the damping valve, only through the hydraulic pump or both through the damping valve and the hydraulic pump.

The fact that the regulating and control device "increasingly closes" the damping valve during driving operation means in particular that the regulating and control device does not suddenly move the damping valve from an open to a closed state, but that the regulating and control device slowly moves the damping valve from its open state to the closed state with the aim of increasing the electrical power output of the hydraulic pump. This closing does not have to take place continuously and evenly. The damping valve can also be fully opened again for a short time.

Closing the damping valve increases the volume flow of hydraulic fluid that flows through the hydraulic pump. As a result, the hydraulic pump generates more electrical energy compared to a state in which the damping valve is fully open. In this case, "more" electrical energy means that more electrical energy is generated when the damping valve is closed than when the damping valve is open. This means in particular that the more the damping valve is closed, the more electrical energy is generated.

In the present case, the fact that electrical energy is "generated" by the hydraulic pump in the recuperation mode means in particular that the kinetic energy of the drive shaft of the hydraulic pump motor is converted into electrical energy. In the present case, "electrical power" is understood to mean the electrical energy converted in a period of time or a time interval in relation to this period of time or this time interval. This power is, for example, delivered to the energy storage device mentioned above, for example in the form of an accumulator, which can store and release the electrical energy generated by the hydraulic pump.

As previously mentioned, the damping valve influences the driving comfort of the vehicle. When the damping valve is closed, driving comfort is at its lowest. In particular, the chassis device is then "hard". When the damping valve is open, driving comfort is at its highest. In particular, the chassis device is then "soft". The regulating and control device preferably controls the damping valve in such a way that the hydraulic pump is operated in recuperation mode as often and as efficiently as possible, so that as much electrical energy as possible is generated, which can be stored in the energy storage device and, as a result, a drive element of the chassis device can be operated for as long as possible. This can increase the range of the vehicle.

For example, the control and regulation device can control the damping valve, in particular based on the charge level of the energy storage device and/or sensor data from the sensor system, in such a way that it closes more and more during the course of driving, so that more and more hydraulic fluid is passed through the hydraulic pump over the course of driving. The chassis device therefore becomes increasingly "harder", but the range of the vehicle increases. Nevertheless, it is possible to control the chassis device passively, semi-actively and/or actively at the same time. For this purpose, the recuperation mode can be interrupted briefly, for example.

A bypass valve or bypass valve can be provided, with the help of which the damping valve can be bypassed. Part of the hydraulic fluid can flow through the bypass valve. In contrast to the damping valve, the bypass valve is preferably not switchable, in particular not adjustable and/or controllable. The bypass valve is in its simplest design In particular, the bypass valve is a passage, for example in the form of a hole, of a defined size. However, the bypass valve can alternatively also be adjustable and/or controllable. In this case, the bypass valve can be controlled by the regulating and control device. The bypass valve can, for example, be a passive and pressure-controlled valve. However, the bypass valve can also be an electronically controlled proportional valve.

Driving comfort can be improved with the help of the bypass valve. The bypass valve prevents a sudden increase in hydraulic pressure at the damping valve when the hydraulic cylinder compresses, as the bypass valve allows a small volume flow of hydraulic fluid to bypass the damping valve.

According to one embodiment, the hydraulic pump is in fluid communication with the hydraulic cylinder by means of exactly one first hydraulic line, wherein the hydraulic pump is in fluid communication with the gas spring accumulator by means of exactly one second hydraulic line.

As previously mentioned, the hydraulic cylinder or the housing of the hydraulic cylinder preferably has exactly one hydraulic connection to which the first hydraulic line can be connected. The first hydraulic line fluidically connects the hydraulic pump to the hydraulic cylinder. The second hydraulic line fluidically connects the hydraulic pump to the gas spring accumulator.

According to a further embodiment, the damping valve is arranged in or on a third hydraulic line branching off from the first hydraulic line and opening into the second hydraulic line.

The third hydraulic line preferably runs parallel to the first hydraulic line and parallel to the second hydraulic line. In particular, the third hydraulic line branches off from the first hydraulic line at a first branch. The third hydraulic line flows into the second hydraulic line, in particular at a second branch. The third hydraulic line is a bypass line or can be referred to as such.

According to a further embodiment, the chassis device further comprises an energy storage device which stores electrical energy generated by the hydraulic pump.

The energy storage device can be assigned to several chassis devices. The energy storage device is preferably a rechargeable battery or accumulator. The energy storage device can be used to supply power to the hydraulic pump in order to put it into pump mode. In recuperation mode, the hydraulic pump can charge the energy storage device. The energy storage device can also be used to supply power to the previously mentioned drive element in order to drive the wheel assigned to the chassis device. The drive element can be a wheel hub motor, for example. However, the drive element can also be any other electric motor. In this case, a drive element can be assigned to several wheels, for example.

According to a further embodiment, the hydraulic cylinder, the gas spring accumulator and the hydraulic pump form a fluidically sealed primary system of the chassis device.

The fact that the primary system is "fluidically sealed" means in particular that no hydraulic fluid is pumped out of or into the primary system. A volume or amount of hydraulic fluid in the primary system is therefore constant or unchangeable. The chassis device can be operated in a primary mode with the aid of the primary system. The damping valve and the hydraulic pump form in particular a regulating and control unit of the chassis device, preferably of the primary system.

According to a further embodiment, the regulating and control device is designed to regulate the primary system with a passive control, a semi-active control or an active control, wherein the regulating and control device controls neither the damping valve nor the hydraulic pump in the passive control, wherein the regulating and control device only controls the damping valve in the semi-active control, and wherein the regulating and control device controls both the damping valve and the hydraulic pump in the active control.

Accordingly, in passive control, the hydraulic pump is preferably switched off. In this case, the damping valve is preferably not regulated or adjusted. In passive control, the hydraulic pump can be in recuperation mode. In semi-active control, the hydraulic pump is still switched off or is in recuperation mode, but the damping valve is regulated. In active control, the hydraulic pump is switched on, with one or no parallel regulation of the damping valve. During active control, the hydraulic pump can control a volume flow of hydraulic fluid. between the hydraulic cylinder and the gas spring accumulator. For example, the inclination of the vehicle can be varied in a longitudinal direction and/or in a transverse direction, for example to compensate for the inclination of the vehicle or to dynamically steer into curves. The hydraulic pump can also be switched to recuperation mode during active control.

According to a further embodiment, the chassis device further comprises a secondary system which can be brought into fluid communication with the primary system by means of a valve assembly.

The valve assembly is in particular a three-way valve. The terms “valve assembly” and “three-way valve” can therefore be interchanged as desired in this case. In particular, the valve assembly can be switched from a first switching state to a second switching state and vice versa. For this purpose, the valve assembly is operatively connected to the regulating and control device. With the help of the valve assembly, the secondary system can thus be connected to the primary system and separated from it again. The chassis device can then be operated in secondary operation when the valve assembly is in the second switching state. For example, in secondary operation, a vehicle height can be dynamically regulated to compensate for uneven ground. Furthermore, the vehicle height can be adjusted slowly, for example when the vehicle is stationary, to adjust the height and/or to adjust the ground clearance of the vehicle. In secondary operation, hydraulic fluid can be pumped from the secondary system to the primary system or vice versa. The valve assembly can preferably be bidirectionally flowed through by the hydraulic fluid. This means in particular that the valve assembly can be flowed through with the hydraulic fluid in two oppositely oriented flow directions both in the first switching state and in the second switching state. In particular, the hydraulic fluid can be conveyed through the valve assembly in both flow directions in both switching states.

According to a further embodiment, the valve assembly is arranged between the gas spring accumulator and the hydraulic pump.

The valve assembly is further preferably arranged between the second branch of the third hydraulic line and the second hydraulic line and the hydraulic pump. The valve assembly is thus provided in or on the second hydraulic line.

According to a further embodiment, the valve assembly can be switched with the aid of the regulating and control device from a first switching state, in which the secondary system is fluidically separated from the primary system, to a second switching state, in which the hydraulic pump is fluidically separated from the gas spring accumulator and the secondary system is fluidically connected to the hydraulic pump.

This means in particular that in the second switching state the hydraulic fluid cannot flow from the hydraulic cylinder through the hydraulic pump to the gas spring accumulator and vice versa. Rather, the hydraulic fluid can flow from the hydraulic cylinder through the hydraulic pump to the secondary system and vice versa.

According to a further embodiment, the secondary system has a hydraulic accumulator in which hydraulic fluid is stored.

The hydraulic accumulator is preferably fluidically connected to the valve assembly by means of a fourth fluid line. The hydraulic accumulator preferably has a housing in which hydraulic fluid is accommodated. The hydraulic fluid is separated from a gas accommodated in the housing of the hydraulic accumulator by means of a membrane. The gas can be nitrogen, for example. With the help of the gas, pressure can be exerted indirectly via the membrane on the hydraulic fluid in the hydraulic accumulator. The hydraulic accumulator is preferably a gas spring accumulator and can also be referred to as such.

Furthermore, a vehicle with at least one such chassis device is proposed.

The vehicle is preferably a motor vehicle, in particular a passenger car. The vehicle can also be a commercial vehicle, for example a truck, a harvester or a construction machine. The vehicle can also be a military vehicle. The vehicle can comprise an internal combustion engine or an internal combustion engine. The internal combustion engine can be a diesel engine or a gasoline engine. The vehicle is in particular a hybrid vehicle. This means that in addition to the internal combustion engine, the vehicle has at least one electric motor in the form of the previously mentioned drive element. The vehicle can also be an electric vehicle. In this case, the vehicle is driven purely electrically. The vehicle preferably comprises several chassis devices. In particular, each wheel of the vehicle is assigned such a chassis device. However, it is not excluded that the chassis devices have common components. or components. For example, all chassis devices of the vehicle can have a common regulating and control device. In particular, the vehicle has four chassis devices, each chassis device being assigned a wheel. The chassis devices form a chassis of the vehicle with the previously mentioned chassis.

Furthermore, a method for operating a chassis device for a wheel of a vehicle is proposed. The chassis device has a hydraulic cylinder in which hydraulic fluid is accommodated, a gas spring accumulator in which hydraulic fluid is also accommodated, an adjustable damping valve which is in fluid communication with both the hydraulic cylinder and the gas spring accumulator, a hydraulic pump which is in fluid communication with both the hydraulic cylinder and the gas spring accumulator, and a regulating and control device for continuously opening and closing the damping valve and for switching the hydraulic pump from a pumping mode to a recuperation mode and vice versa, wherein the damping valve and the hydraulic pump are connected in parallel to one another. The method comprises the following steps: a) carrying out a driving operation of the chassis device, wherein hydraulic fluid flows from the hydraulic cylinder to the gas spring accumulator and vice versa through the damping valve and/or through the hydraulic pump, b) increasingly closing the damping valve with the aid of the regulating and control device in order to increase a volume flow of the hydraulic fluid flowing through the hydraulic pump, and c) bringing the hydraulic pump into the recuperation mode with the aid of the regulating and control device, so that an electrical power output by the hydraulic pump during the recuperation mode increases with increasing closing of the damping valve.

Accordingly, the method is carried out in particular with the aid of the chassis device. Steps a) to c) can be carried out simultaneously. During driving, the piston is moved in particular into the housing of the hydraulic cylinder and out of it again. Hydraulic fluid flows from the hydraulic cylinder to the gas spring accumulator and vice versa. This hydraulic fluid then flows through the damping valve and/or through the hydraulic pump. By closing the damping valve during step b), the volume flow of the hydraulic fluid flowing through the hydraulic pump is increased. Since the hydraulic pump is in the recuperation mode in step c), more electrical energy is generated accordingly due to the increased volume flow flowing through the hydraulic pump. The electrical power delivered by the hydraulic pump in the recuperation mode increases. As previously mentioned, driving comfort is reduced by closing the damping valve, but at the same time the range of the vehicle is increased by increasing the electrical power delivered by the hydraulic pump in the recuperation mode.

According to one embodiment, the hydraulic cylinder, the gas spring accumulator and the hydraulic pump form a fluidically sealed primary system of the chassis device, wherein the primary system is controlled by the control and regulating device with a passive control, a semi-active control or an active control, wherein in the passive control neither the damping valve nor the hydraulic pump are controlled by the control and regulating device, wherein in the semi-active control only the damping valve is controlled by the control and regulating device, and wherein in the active control both the damping valve and the hydraulic pump are controlled by the control and regulating device.

In passive control, the damping valve is, for example, in the closed state or in the open state or in any intermediate state between the open state and the closed state. During passive control, hydraulic fluid can flow through the hydraulic pump to generate electrical energy. In semi-active control, the damping valve is controlled by the control and regulating device in such a way that it can be opened and closed as desired. In active control, the hydraulic pump is also controlled in addition to the damping valve. This means that, for example, in pump mode, a volume flow between the hydraulic cylinder and the gas spring accumulator can be actively superimposed.

According to a further embodiment, a secondary system is also provided which can be brought into fluid communication with the primary system by means of a valve assembly, wherein the valve assembly is switched by means of the regulating and control device from a first switching state in which the secondary system is fluidically separated from the primary system to a second switching state in which the hydraulic pump is fluidically separated from the gas spring accumulator and the secondary system is fluidically connected to the hydraulic pump.

In the first switching state, the chassis device is preferably operated in the primary mode. In the second switching state, the Chassis device preferably operated in secondary mode. However, a mixed operation of primary and secondary operation is also possible. As previously mentioned, the control in primary mode can be passive, semi-active or active. During secondary mode, additional hydraulic fluid can be pumped from the hydraulic accumulator of the secondary system into the primary system via the valve assembly in a coordinated manner by the hydraulic pump or can be either passively drained or actively pumped out of it. A filling level of hydraulic fluid, i.e. a total amount of hydraulic fluid, in the primary system can be changed in this way. This enables, for example, the vehicle height of the vehicle to be changed. Furthermore, this also makes it possible to specifically adjust the vehicle height of the vehicle depending on the loading state of the vehicle. In mixed mode, the secondary system can be switched on in parallel to the primary system to adjust the vehicle height while driving using the hydraulic pump. With the help of the hydraulic pump, a coordinated pumping in or out of hydraulic fluid can be carried out. Meanwhile, the chassis device acts passively or semi-actively with the help of the damping valve.

According to a further embodiment, in order to increase or decrease a vehicle height of the vehicle, hydraulic fluid is pumped from the secondary system into the primary system or from the primary system into the secondary system.

As previously mentioned, the vehicle height can be increased or decreased while driving. However, the vehicle height can also be changed when the vehicle is stationary. This can, for example, compensate for the vehicle's loading condition. For example, the hydraulic pump can pump the hydraulic fluid from the secondary system into the primary system or vice versa. Alternatively, the hydraulic fluid can also be passively pushed from the primary system into the secondary system. In this case, the hydraulic pump can be in recuperation mode.

The embodiments and features described for the proposed chassis device apply accordingly to the proposed vehicle and/or to the proposed method.

In this case, "one" is not necessarily to be understood as being limited to just one element. Rather, several elements, such as two, three or more, can also be provided. Any other counting word used here is also not to be understood as meaning that there is a limitation to the exact number of elements mentioned. Rather, numerical deviations upwards and downwards are possible, unless otherwise stated.

Further possible implementations of the chassis device, the vehicle and/or the method also include combinations of features or embodiments described above or below with regard to the exemplary embodiments that are not explicitly mentioned. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the chassis device, the vehicle and/or the method.

• 1 zeigt eine schematische Seitenansicht einer Ausführungsform eines Fahrzeugs;
• 2 zeigt eine schematische Ansicht einer Ausführungsform einer Fahrwerkvorrichtung für das Fahrzeug gemäß 1;
• 3 zeigt eine weitere schematische Ansicht der Fahrwerkvorrichtung gemäß 2; und
• 4 zeigt ein schematisches Blockdiagramm einer Ausführungsform eines Verfahrens zum Betreiben der Fahrwerkvorrichtung gemäß 2.

Further advantageous embodiments and aspects of the chassis device, the vehicle and/or the method are the subject of the subclaims and the embodiments of the invention described below. The chassis device, the vehicle and/or the method are explained in more detail below using preferred embodiments with reference to the attached figures.

• 1 shows a schematic side view of an embodiment of a vehicle;
• 2 shows a schematic view of an embodiment of a chassis device for the vehicle according to 1 ;
• 3 shows a further schematic view of the chassis device according to 2 ; and
• 4 shows a schematic block diagram of an embodiment of a method for operating the chassis device according to 2 .

In the figures, identical or functionally equivalent elements have been given the same reference symbols unless otherwise stated.

The 1 shows a schematic side view of an embodiment of a vehicle 1.

The vehicle 1 is a motor vehicle, in particular a passenger car. The vehicle 1 can also be a commercial vehicle, for example a truck, a harvester or a construction machine. The vehicle 1 can also be a military vehicle. However, it is assumed below that the vehicle 1 is a motor vehicle, in particular a passenger car.

The vehicle 1 comprises a body 2, which encloses a passenger compartment or vehicle interior 3 of the vehicle 1. In the vehicle interior 3, a driver and passenger guests. The body 2 delimits an environment 4 of the vehicle 1 from the vehicle interior 3. The vehicle interior 3 is accessible from the environment 4 by means of doors.

The vehicle 1 comprises a chassis with several wheels 5, 6. The number of wheels 5, 6 is basically arbitrary. Preferably, the vehicle 1 has four wheels 5, 6. However, the vehicle 1 can have, for example, six wheels 5, 6. The wheels 5, 6 are part of a chassis of the vehicle 1. Only two wheels 5, 6 can be driven. However, all wheels 5, 6 can also be driven. In this case, the vehicle 1 is an all-wheel drive vehicle. Preferably, two front wheels 5 are steerable. However, all wheels 5, 6 can also be steerable.

The vehicle 1 can comprise an internal combustion engine or a combustion engine. The combustion engine can be a diesel engine or a gasoline engine. The vehicle 1 can also be a hybrid vehicle. In this case, the vehicle 1 has at least one electric motor in addition to the combustion engine. The vehicle 1 can have several electric motors. In this case, the electric motors can be wheel hub motors. The vehicle 1 can be an electric vehicle. In this case, the vehicle 1 is purely electrically powered. It is assumed below that the vehicle 1 is an electric vehicle.

The vehicle 1 moves along a surface 7 using the wheels 5, 6. The surface 7 can be a road or any other type of terrain. The surface 7 can have uneven ground 8, for example in the form of bumps or stones. If the vehicle 1 moves over the uneven ground 8, the wheels 5, 6 can compress and rebound again.

The vehicle 1 is assigned a coordinate system with a first spatial direction or x-direction x, a second spatial direction or y-direction y and a third spatial direction or z-direction z. The x-direction x can also be referred to as the longitudinal direction. The y-direction y can also be referred to as the vertical direction. The z-direction z can also be referred to as the transverse direction. The directions x, y, z are oriented perpendicular to each other. A direction of gravity g is in the orientation of the 1 oriented from top to bottom. The direction of gravity g runs parallel to the y-direction y.

The 2 and 3 each show a schematic view of an embodiment of a chassis device 9 for the vehicle 1.

The vehicle 1 can have several chassis devices 9. In particular, each wheel 5, 6 can be assigned such a chassis device 9. For example, with four wheels 5, 6, four chassis devices 9 can be provided. However, this does not exclude the possibility that chassis devices 9 of different wheels 5, 6 can have common parts or components.

The chassis device 9 is assigned a chassis 10, which is in the 2 and 3 is only shown in a very simplified manner. Several chassis devices 9 can be provided on the chassis 10. The chassis 10, together with the chassis device 9 or together with several chassis devices 9, forms a chassis 11 of the vehicle 1. For example, the chassis 10 together with four chassis devices 9 forms the chassis 11.

The chassis device 9 may further comprise a wheel 5 which is in the 2 and 3 is only shown in a very schematic manner. In the following, reference is made only to wheel 5. All statements relating to wheel 5 are applicable to the other wheels 5, 6 of vehicle 1 and vice versa.

The wheel 5 is connected to the chassis 10 by means of a hydraulic cylinder 12. The hydraulic cylinder 12 is coupled or operatively connected to the wheel 5, for example via a wheel carrier and/or other components. Preferably, each wheel 5, 6 is assigned a hydraulic cylinder 12. The hydraulic cylinder 12 comprises a housing 13, which is connected to the chassis 10 by means of a connection element 14, for example in the form of a ball head. Exactly one hydraulic connection 15 is provided on the housing 13.

The housing 13 accommodates a piston 16 that can be moved into and out of the housing 13 and is connected to the wheel 5 by means of a connecting element 17, for example in the form of a ball head. The movement of the piston 16 into and out of the housing 13 is indicated by means of a double arrow 18. A receiving space 19 is provided between the housing 13 and the piston 16. The hydraulic connection 15 opens into the receiving space 19. The receiving space 19 can also be referred to as a hydraulic chamber.

The housing 13 is at least partially filled with a hydraulic fluid 20. In particular, the receiving space 19 is filled with the hydraulic fluid 20. The hydraulic fluid 20 can be a hydraulic oil. The piston 16 can displace the hydraulic fluid 20 from the housing 13. Conversely the hydraulic fluid 20 can move the piston 16 out of the housing 13.

A first hydraulic line 21 is connected to the hydraulic cylinder 12, with the aid of which hydraulic fluid 20 can be supplied to or discharged from the hydraulic cylinder 12. The first hydraulic line 21 is connected to the hydraulic connection 15. The first hydraulic line 21 leads to an electromagnetic hydraulic pump 22. Each wheel 5, 6 can be assigned its own hydraulic pump 22. Alternatively, a common hydraulic pump 22 can also be assigned to several wheels 5, 6. The hydraulic pump 22 has a motor 23, which can also function as a generator for generating electricity.

A second hydraulic line 24 leads from the hydraulic pump 22 to a gas spring accumulator 25. Each wheel 5, 6 can be assigned its own gas spring accumulator 25. Alternatively, a common gas spring accumulator 25 can be assigned to several wheels 5, 6. The hydraulic pump 22 is a servo pump. The hydraulic pump 22 is an electrohydraulic pump. In particular, the hydraulic pump 22 is a four-quadrant servo pump. The term “four-quadrant operation” of the hydraulic pump 22 is to be understood in particular as meaning that it operates with alternating directions of rotation and alternating directions of torque.

The gas spring accumulator 25 comprises a housing 26 in which a prestressed membrane 27 is accommodated. Hydraulic fluid 20 and a gas 28, for example nitrogen, are accommodated in the housing 26. The membrane 27 separates the hydraulic fluid 20 from the gas 28. The second hydraulic line 24 opens into an area of the housing 26 in which the hydraulic fluid 20 is accommodated.

A third hydraulic line 30 branches off from the first hydraulic line 21 at a first branch 29, which bypasses the hydraulic pump 22. The third hydraulic line 30 flows into the second hydraulic line 24 at a second branch 31 in front of the gas spring accumulator 25. An adjustable and/or controllable damping valve 32 is provided on or in the third hydraulic line 30. The damping valve 32 functions as an adjustable throttle. The damping valve 32 can therefore also be referred to as a throttle valve. Each wheel 5, 6 can be assigned its own damping valve 32. Alternatively, a common damping valve 32 can also be assigned to several wheels 5, 6.

The hydraulic pump 22 and the damping valve 32 together form a control and regulating unit 33. The hydraulic pump 22 and the damping valve 32 are connected in parallel in the control and regulating unit 33. Each wheel 5, 6 can be assigned its own control and regulating unit 33. Alternatively, a common control and regulating unit 33 can be assigned to several wheels 5, 6. The hydraulic cylinder 12, the hydraulic lines 21, 24, 30, the hydraulic pump 22, the gas spring accumulator 25 and the damping valve 32 form a primary system 34 of the chassis device 9.

A valve assembly 35 is arranged in or on the second hydraulic line 24. The valve assembly 35 can be a three-way valve. The valve assembly 35 is arranged between the hydraulic pump 22 and the second branch 31 of the second hydraulic line 24. The valve assembly 35 is in fluid communication with a hydraulic accumulator 37 by means of a fourth hydraulic line 36. The hydraulic accumulator 37 has a housing 38 in which a prestressed membrane 39 is accommodated. The membrane 39 separates hydraulic fluid 20 accommodated in the housing 38 from a gas 40, for example nitrogen. The valve assembly 35, the fourth hydraulic line 36 and the hydraulic accumulator 37 form a secondary system 41 of the chassis device 9.

The chassis device 9 has a drive element 42 and an energy storage device 43. The drive element 42 is an electric motor. The drive element 42 can be a wheel hub motor assigned to the wheel 5. The energy storage device 43 can be an accumulator that supplies current to the drive element 42. The hydraulic pump 22 can also be operated with the aid of the energy storage device 43. The energy storage device 43 can thus be operatively connected both to the hydraulic pump 22 and to the drive element 42.

The chassis device 9 further comprises a control and regulating device 44. Each wheel 5, 6 can be assigned its own control and regulating device 44. Alternatively, a common control and regulating device 44 can also be assigned to several wheels 5, 6. The control and regulating device 44 is designed to control the hydraulic pump 22, the damping valve 32, the valve assembly 35 and/or the drive element 42. A wireless or wired connection can be provided for this purpose. The control and regulating device 44 can also be suitable for carrying out, monitoring and/or controlling a charging process of the energy storage device 43.

Furthermore, the control and regulation device 44 can be designed to receive sensor signals from a sensor system 45, to evaluate them and to control the hydraulic pump 22, the damping valve 32, the valve assembly 35 and/or the drive element 42 based on these sensor signals. control. The sensor system 45 can have a wide variety of sensors. For example, the sensor system 45 can include pressure sensors that are suitable for detecting a respective hydraulic pressure of the hydraulic fluid 20 in the primary system 34 and/or in the secondary system 41. The sensor system 45 can also have one pressure sensor or several pressure sensors for detecting a hydraulic pressure at or in the hydraulic connection 15.

Furthermore, the sensor system 45 can also include a displacement sensor, which can, for example, detect how far the piston 16 has moved into the housing 13. The sensor system 45 can also have speed sensors, acceleration sensors, inertia sensors and/or temperature sensors. In principle, however, the sensor system 45 can have any type of sensor. The sensor system 45 can also be suitable for detecting and/or evaluating a motor current of the motor 23 of the hydraulic pump 22 and/or the drive element 42. The sensor system 45 can also detect and/or evaluate a hydraulic pressure in or on the hydraulic pump 22. A pressure sensor can be provided on the hydraulic pump 22 for this purpose. Several pressure sensors can also be assigned to the hydraulic pump 22.

A bypass line 46 with a bypass valve 47 branches off from the third hydraulic line 30. The bypass line 47 flows out of the third hydraulic line 30 upstream of the damping valve 32. The bypass line 46 flows back into the third hydraulic line 30 downstream of the damping valve 32. The bypass valve 47 is connected in parallel to the damping valve 32 and the hydraulic pump 22.

The bypass valve 47 can be used to bypass the damping valve 32. In contrast to the damping valve 32, the bypass valve 47 is preferably not switchable, in particular not adjustable and/or controllable. In its simplest form, the bypass valve 47 is a passage, for example in the form of a hole, of a defined size. Alternatively, a valve plate can also be integrated.

However, the bypass valve 47 can alternatively also be adjustable and/or controllable. In this case, the bypass valve 47 can be controlled by the regulating and control device 44. The bypass valve 47 can, for example, be a passive and pressure-controlled valve. However, the bypass valve 47 can also be an electronically controlled proportional valve.

The functionality of the chassis device 9 is explained below. The valve assembly 35 is initially inserted into a 2 shown first switching state Z1, in which the secondary system 41 is fluidically separated from the primary system 34. This means that no hydraulic fluid 20 can flow from the secondary system 41 into the primary system 34 and vice versa.

In the first switching state Z1, the primary system 34 functions as a hydropneumatic suspension for the wheel 5. The hydraulic fluid 20 in the hydraulic cylinder 12, the hydraulic lines 21, 24, 30, the bypass line 46 and the gas spring accumulator 25 forms a hydraulic column within which the regulating and control unit 33 comprising the hydraulic pump 22 and the damping valve 32 is arranged.

The aforementioned hydraulic column is arranged in a first part within the hydraulic cylinder 12, wherein this first part acts as a spring strut for the wheel 5 and adjusts a vehicle height of the vehicle 1 through its mechanical arrangement. A second part of the hydraulic column is arranged within the gas spring accumulator 25, the gas pressure of the gas 28 of which acts as a suspension element for the wheel 5. The gas 28 is pressurized by the hydraulic fluid 20 from the hydraulic fluid 20 held in the hydraulic cylinder 12.

The two previously mentioned parts of the hydraulic column together form the hydraulic column. The primary system 34 thus represents a, in particular hermetically sealed, system in the first switching state Z1, which keeps the vehicle 1 in equilibrium with springs at the previously mentioned vehicle height. The regulation and control unit 33 is located between the two parts of the hydraulic column.

As long as only the primary system 34 is in operation, that is, as long as the valve assembly 35 is in the first switching state Z1, the chassis device 9 can be controlled in a primary mode as explained below. As previously mentioned, the control unit 33 located between the two parts of the hydraulic column comprises a parallel connection of the hydraulic pump 22 and the damping valve 32.

The damping valve 32 has a reverse damping principle, since the damping valve 32 is stationary and the throttling effect is caused by the hydraulic fluid 20 flowing through the damping valve 32. A damping effect of the damping valve 32 can be controlled, for example, as with a semi-active damper. For this purpose, the damping valve 32 is controlled in a suitable manner by means of the regulating and control device 44.

The hydraulic pump 22 can actively superimpose a volume flow between the two parts of the hydraulic column or between the hydraulic cylinder 12 and the gas spring accumulator 25. This volume flow can be generated in a passive mode by a volume shift of the hydraulic fluid 20 between the two parts of the hydraulic column or between the hydraulic cylinder 12 and the gas spring accumulator 25, which is stimulated by the ground 7 or by driving maneuvers.

In this case, “actively superimposing” means that the hydraulic pump 22 can pump the hydraulic fluid 20 from the gas spring accumulator 25 into the hydraulic cylinder 12 or vice versa. The hydraulic pump 22 and the damping valve 32 can be controlled in a coordinated manner and represent the control unit 33 in the primary system 34.

The control in primary operation can be passive, semi-active or active. “Passive” means that the hydraulic pump 22 is switched off and the damping valve 32 is not regulated. “Semi-active” means that the hydraulic pump 22 is switched off, but the damping valve 32 is regulated.

“Active” means that the hydraulic pump 22 is switched on, with one or no parallel control of the damping valve 32. The hydraulic pump 22 can be controlled both as an actuating element and recuperatively to generate power and feed it into the energy storage device 43. A “recuperative operation”, “recuperation operation” or “recuperation mode” of the hydraulic pump 22 means that the hydraulic fluid 20 flows through the hydraulic pump 22 and drives the motor 23 of the hydraulic pump 22, which then acts as a generator to generate power. A total amount or a total volume of the hydraulic fluid 20 is constant in the primary operation and thus remains unchanged in the primary system 34.

In contrast to the recuperation mode, a "pumping operation", "pumping operation" or "pumping mode" of the hydraulic pump 22 means that the hydraulic pump 22 is driven and pumps the hydraulic fluid 20. Both the recuperation mode and the pumping mode function bidirectionally. This means that both the recuperation mode and the pumping mode are independent of the flow direction of the hydraulic fluid 20 through the hydraulic pump 22. A change between the pumping mode and the recuperation mode can be possible, for example, with a temporal resolution of up to 50 Hz or more.

The bypass valve 47 improves driving comfort. The reason for this is that the damping valve 32 is slow. When the hydraulic cylinder 12 is compressed, hydraulic pressure is built up. This hydraulic pressure is then applied to the damping valve 32 and is only released when the damping valve 32 opens. Since the damping valve 32 does not open immediately, but rather with a slight delay, the hydraulic cylinder 12 does not work sensitively enough, since it is always blocked for a short time at first. The hydraulic cylinder 12 is blocked for as long as the opening time of the damping valve 32 lasts.

In order to prevent this blocking of the hydraulic cylinder 12, a small part of the hydraulic fluid 20 is passed through the bypass valve 47 so that this initial effect of stalling does not occur. The small initial amount of the hydraulic fluid 20 is then passed, for example, through a hole which forms the bypass valve 47. This gives the damping valve 32 time to open and let the remaining hydraulic fluid 20 through. A volume flow of the hydraulic fluid 20 through the bypass valve 47 is so small that in the event of strong compression or in normal driving operation and when setting a recuperation rate of the hydraulic pump 22, the volume flow of the hydraulic fluid 20 passed through the bypass valve 47 is negligible.

Furthermore, the piston 16 requires a certain amount of movement within the housing 13 in order to build up the hydraulic pressure. If the bypass valve 47 were omitted, this movement would not be possible due to the previously explained inertia of the damping valve 32. Without the bypass valve 47, a movement of the piston 16 would lead to a sudden increase in the hydraulic pressure. This would lead to a significant deterioration in driving comfort.

If the valve assembly 35 is switched from the first switching state Z1 to a 3 shown second switching state Z2, the hydraulic accumulator 37 is fluidically connected via the fourth hydraulic line 36 to the second hydraulic line 24 and thus to the hydraulic pump 22.

The valve assembly 35 can be bidirectionally flowed through with the hydraulic fluid 20. This means in particular that the valve assembly 35 the hydraulic fluid 20 can flow through the valve assembly 35 in two oppositely oriented flow directions both in the first switching state Z1 and in the second switching state Z2. In particular, the hydraulic fluid 20 can be conveyed through the valve assembly 35 in both flow directions in both switching states Z1, Z2.

As soon as the valve assembly 35 is switched to the second switching state Z2, the chassis device 9 is in secondary operation. In the second switching state Z2, the gas spring accumulator 25 is only in fluid connection with the hydraulic cylinder 12 via the third hydraulic line 30 and the damping valve 32. A direct or immediate fluid connection between the gas spring accumulator 25 and the hydraulic pump 22 via the second hydraulic line 24 no longer exists in the second switching state Z2.

As previously mentioned, however, this does not exclude the possibility that the gas spring accumulator 25 in the second switching state Z2 is indirectly or indirectly in fluid communication with the gas spring accumulator 25 via the first hydraulic line 21, the third hydraulic line 30 branching off from the first hydraulic line 21 at the first branch 29 and the second hydraulic line 24 connected to the third hydraulic line 30 at the second branch 31. By moving the valve assembly 35 from the second switching state Z2 to the first switching state Z1, the chassis device 9 can be returned to primary operation.

The secondary system 41 comprises, as previously mentioned, the separate hydraulic accumulator 37, which is preloaded, the valve assembly 35 and the fourth hydraulic line 36. With the help of the valve assembly 35 and the fourth hydraulic line 36, the secondary system 41 can be fluidically connected to the primary system 34 via the hydraulic pump 22.

The control in secondary operation can be carried out as explained below. During secondary operation, additional hydraulic fluid 20 can be pumped from the hydraulic accumulator 37 into the primary system 34 via the valve assembly 35 in a coordinated manner by the hydraulic pump 22, or it can be either passively drained or actively pumped out of the primary system 34. “Passive” means that the hydraulic fluid 20 is pressed through the hydraulic pump 22 into the secondary system 41 without the hydraulic pump 22 pumping the hydraulic fluid 20. “Active” means that the hydraulic pump 22 pumps the hydraulic fluid 20 into the secondary system 41 by expending work.

A filling level of hydraulic fluid 20, i.e. a total amount of hydraulic fluid 20, of the primary system 34 can be changed in this way. This enables, for example, a change in the vehicle height of the vehicle 1 as part of a so-called leveling function. Furthermore, a targeted adjustment of the vehicle height of the vehicle 1 can also be carried out depending on a loading state of the vehicle 1. After the adjustment of the vehicle height has been completed, the chassis device 9 can be put back into primary operation by resetting the valve assembly 35 from the second switching state Z2 to the first switching state Z1.

A mixed operation of primary operation and secondary operation is also possible. The secondary system 41 can also be switched on in parallel to the primary system 34 for adjusting the vehicle height during a journey or driving operation of the vehicle 1 using the hydraulic pump 22. With the help of the hydraulic pump 22, a coordinated pumping in or pumping out of hydraulic fluid 20 can be carried out. Meanwhile, the chassis device 9 acts passively or semi-actively with the help of the damping valve 32.

In the event that the vehicle 1 is an electric vehicle, the hydraulic pump 22 can be used to generate electrical energy and thus to charge the energy storage device 43 while the vehicle 1 is being driven. For this purpose, the chassis device 9 can, for example, be in primary operation. This means that the valve assembly 35 is in the first switching state Z1.

The vehicle 1 now moves over the ground 7, with the wheel 5 compressing and rebounding, for example on uneven ground 8 and/or when cornering. As a result, hydraulic fluid 20 is pumped from the hydraulic cylinder 12 into the gas spring accumulator 25 and from the gas spring accumulator 25 into the hydraulic cylinder 12. As previously mentioned, the damping valve 32 acts as a damper between the hydraulic cylinder 12 and the gas spring accumulator 25.

The damping valve 32 influences the driving comfort of the vehicle 1. The damping valve 32 can be continuously moved between a closed state in which the entire hydraulic fluid 20 is passed through the hydraulic pump 22, to an open state in which the entire hydraulic fluid 20 flows through the damping valve 32 except for a small volume flow that can still flow through the hydraulic pump 22, and vice versa. The damping valve 32 can thus be opened from 0% to 100%. or from 100% to 0%.

When the damping valve 32 is closed, the driving comfort is at its lowest. In particular, the chassis device 9 is then "hard". This state can be selected by a driver for a motorway journey, for example. When the damping valve 32 is open, the driving comfort is at its highest. In particular, the chassis device 9 is then "soft". This state can be selected by the driver for a city journey, for example.

The hydraulic fluid 20 flowing through the hydraulic pump 22 drives the motor 23 of the hydraulic pump 22, which then acts as a generator to generate electricity. The motor 23 can act as a generator both when the hydraulic fluid 20 flows from the hydraulic cylinder 12 to the gas spring accumulator 25 and when the hydraulic fluid 20 flows from the gas spring accumulator 25 to the hydraulic cylinder 12. The more hydraulic fluid 20 flows through the hydraulic pump 22, that is, the more the damping valve 32 is closed, the more electrical energy is generated by the hydraulic pump 22.

In particular, the electrical power of the hydraulic pump 22 increases during the recuperation mode as the damping valve 32 closes. In this case, the term “electrical power” is to be understood as the electrical energy converted in a period of time or a time interval in relation to this period of time or this time interval. In this case, the term “generating” electrical energy is to be understood as converting kinetic energy of the motor 23, in particular a drive shaft of the motor 23, into electrical energy. The hydraulic fluid 20 drives the motor 23, which functions as a generator, or its drive shaft.

Apart from the previously targeted adjustment of the driving comfort by the driver, the regulating and control device 44 can also control the regulating and control unit 33, in particular the damping valve 32, in such a way that the hydraulic pump 22 can be operated in recuperation mode as often and as efficiently as possible, so that the energy storage device 43 can be charged and, as a result, the drive element 42 can be operated for as long as possible. This can increase the range of the vehicle 1.

For example, the regulating and control device 44 can, in particular based on a charge state of the energy storage device 43 and/or sensor data from the sensor system 45, control the damping valve 32 in such a way that it continues to close as the vehicle 1 is driven, so that more and more hydraulic fluid 20 is passed through the hydraulic pump 22 as the driving progresses. The chassis device 9 therefore becomes increasingly "harder". Nevertheless, it is possible to regulate the chassis device 9 passively, semi-actively or actively with the aid of the regulating and control unit 33. For this purpose, the recuperation mode is then briefly interrupted.

The recuperation mode of the hydraulic pump 22 can be carried out in primary operation, in secondary operation and in mixed operation. In secondary operation, the hydraulic fluid 20 flows back and forth between the hydraulic cylinder 12 and the hydraulic accumulator 37 and thus through the hydraulic pump 22.

The chassis device 9 thus fulfills a variety of functions. It is possible to vary the damping behavior to adapt the driving comfort and the handling of the vehicle 1. An inclination of the vehicle 1 in the longitudinal direction x and/or in the transverse direction z can be varied in order to compensate for an inclination of the vehicle 1 or to steer dynamically into curves.

Furthermore, the vehicle height can be dynamically controlled to compensate for uneven ground 8. Furthermore, the vehicle height can be slowly adjusted to adjust the vehicle height and ground clearance when the vehicle 1 is stationary. Energy recovery from wheel and body movements can be achieved with the help of the hydraulic pump 22.

The chassis device 9 thus implements a so-called active suspension system based on a hydro-pneumatic chassis principle. The chassis device 9 is actively controlled by the electromagnetic hydraulic pump 22 in such a way that the hydraulic cylinder 12 functions as a spring strut for the wheel 5, with the hydraulic cylinder 12 being in fluid communication with the gas spring accumulator 25 via the hydraulic lines 21, 24, 30 and the bypass line 46.

The chassis device 9 is controlled by the adjustable and/or controllable damping valve 32, which replaces a decentralized damper for the wheel 5. The damping valve 32 is connected in parallel with the electromagnetic hydraulic pump 22. The primary system 34 is a hermetically sealed system in the first switching state Z1 of the valve assembly 35.

There are no additional elements, such as springs, to support a vehicle weight of the vehicle 1. In an initial state or initial condition, a constant hydraulic pressure prevails in the primary system 34. By using the hydraulic pump 22, a volume of hydraulic fluid 20 is varied according to the displacement principle between the hydraulic cylinder 12 and the gas spring accumulator 25.

The chassis device 9 enables the hydraulic pump 22 to be decoupled from a volume flow of the hydraulic fluid 20 by means of the adjustable and/or controllable damping valve 32. In addition to purely passive operation, the damping valve 32 can also be activated. The recuperation rate of the hydraulic pump 22 can be variably controlled. On the other hand, the hydraulic pump 22 enables an active pressure build-up with a direct or rapid introduction of force. This enables the chassis device 9 to be activated.

The adjustable and/or controllable damping valve 32 can be used to replace a passive damper. It is possible to superimpose and/or control passive damping behavior and actively introduced damping force by switching the hydraulic pump 22 on and off. This can be done while the vehicle 1 is being driven. The hydraulic pump 22 advantageously enables energy recovery. In the event of a fault, a defined damping characteristic results.

This results in a dynamic and slow build-up or control of the vehicle height that is independent of the spring rate. The hydraulic pump 22 does not influence the gas spring accumulator 25. This results in an efficient recuperation mode of 0% in the event that the damping valve 32 is completely open, to 100% in the event that the damping valve 32 is completely closed.

Advantageously, the chassis device 9 has a low level of complexity in its overall architecture by reducing it to a few subsystems. Furthermore, the individual components also have a low level of complexity when the subsystems are integrated into a component of the chassis device 9. For example, the damping valve 32 can be integrated into the hydraulic cylinder 12. The chassis device 9 nevertheless has the comprehensive functionality of an active chassis. The chassis device 9 has an energy-efficient system architecture and the possibility of energy recovery.

The 4 shows a schematic block diagram of an embodiment of a method for operating the chassis device 9.

In the method, the driving operation of the chassis device 9 or the vehicle 1 is carried out in a step S1. During the driving operation, the vehicle moves along the ground 7. The driving operation can include cornering, driving uphill, driving downhill or the like. During the driving operation, the vehicle 1 can also drive over uneven ground 8.

During driving, the piston 16 is moved into the housing 13 of the hydraulic cylinder 12 and out of it again. Hydraulic fluid 20 flows from the hydraulic cylinder 12 to the gas spring accumulator 25 and vice versa. This hydraulic fluid 20 then flows through the damping valve 32 and through the hydraulic pump 22.

In a step S2, the damping valve 32 is increasingly closed with the aid of the regulating and control device 44. “Increasingly” is to be understood in particular to mean that the damping valve 32 is preferably not closed suddenly, but is slowly moved from its open state to the closed state. This closing does not have to take place continuously and evenly. By closing the damping valve 32, a volume flow of the hydraulic fluid 20 flowing through the hydraulic pump 22 is increased.

In a step S3, the hydraulic pump 22 is put into recuperation mode with the aid of the regulating and control device 44, so that the hydraulic pump 22 generates more and more electrical energy as the damping valve 32 closes. A "more" electrical energy is to be understood as meaning that in the closed state of the damping valve 32 more electrical energy is generated per any time interval than in the open state of the damping valve 32. As explained above, this reduces the driving comfort of the vehicle 1, although its range is increased. In particular, during step S3, the electrical power delivered by the hydraulic pump 22 in recuperation mode increases as the damping valve 32 closes.

In the method, the primary system 34 can be controlled by the control and regulating device 44 with a passive control, a semi-active control or an active control. In the passive control, neither the damping valve 32 nor the hydraulic pump 22 are controlled by the control and regulating device 44. In the semi-active control, only the damping valve 32 is controlled by the control and regulating device 44 and in the active control, both the damping valve 32 and the hydraulic pump 22 is also controlled by the regulating and control device 44.

In the method, the valve assembly 35 can be switched with the aid of the regulating and control device 44 from the first switching state Z1, in which the secondary system 41 is fluidically separated from the primary system 34, to the second switching state Z2, in which the hydraulic pump 22 is fluidically separated from the gas spring accumulator 25 and the secondary system 41 is fluidically connected to the hydraulic pump 22. In order to increase or reduce the vehicle height of the vehicle 1, hydraulic fluid 20 can be pumped from the secondary system 41 into the primary system 34 or from the primary system 34 into the secondary system 41.

In the method, the regulating and control device 44 controls the damping valve 32 and the hydraulic pump 22 in particular in such a way that an optimization is achieved with regard to the possible achievable range of the vehicle 1. The regulating and control device 44 can thus control or regulate the damping valve 32 and the hydraulic pump 22 in such a way that the greatest possible range or any predetermined range of the vehicle 1 can be achieved.

In particular, the regulating and control device 44 can also control or regulate the damping valve 32 and the hydraulic pump 22 depending on a charge state of the energy storage device 43 of the chassis device 9 or of the vehicle 1. For example, this is done in such a way that a predetermined charge state of the energy storage device 43 is not undercut during driving. The "charge state" can be specified in percentage values, with 100% representing a fully charged energy storage device 43.

Although the present invention has been described using exemplary embodiments, it can be modified in many ways.

REFERENCE SYMBOL LIST

1

vehicle

2

body

3

vehicle interior

4

Vicinity

5

wheel

6

wheel

7

underground

8

uneven ground

9

chassis device

10

chassis

11

chassis

12

hydraulic cylinders

13

Housing

14

connection element

15

hydraulic connection

16

Pistons

17

connection element

18

double arrow

19

recording room

20

hydraulic fluid

21

hydraulic line

22

hydraulic pump

23

Motor

24

hydraulic line

25

gas spring accumulator

26

Housing

27

membrane

28

gas

29

branch

30

hydraulic line

31

branch

32

damping valve

33

control unit

34

primary system

35

valve assembly

36

hydraulic line

37

hydraulic accumulator

38

Housing

39

membrane

40

gas

41

secondary system

42

drive element

43

energy storage

44

control and regulation device

45

sensor technology

46

bypass line

47

bypass valve

G

direction of gravity

S1

Step

S2

Step

S3

Step

x

x-direction/longitudinal direction

y

y-direction/vertical direction

z

z-direction/transverse direction

Z1

switching state

Z2

switching state

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 10 2019 111 980 A1 [0003]

Claims (15)

Chassis device (9) for a wheel (5, 6) of a vehicle (1), with a hydraulic cylinder (12) in which hydraulic fluid (20) is accommodated, a gas spring accumulator (25) in which hydraulic fluid (20) is also accommodated, an adjustable damping valve (32) which is in fluid communication with both the hydraulic cylinder (12) and the gas spring accumulator (25), a hydraulic pump (22) which is in fluid communication with both the hydraulic cylinder (12) and the gas spring accumulator (25), and a regulating and control device (44) for continuously opening and closing the damping valve (32) and for switching the hydraulic pump (22) from a pumping mode to a recuperation mode and vice versa, wherein the damping valve (32) and the hydraulic pump (22) are connected in parallel to one another, wherein during driving operation of the chassis device (9) hydraulic fluid (20) is supplied from the hydraulic cylinder (12) to the Gas spring accumulator (25) and vice versa through the damping valve (32) and/or through the hydraulic pump (22), and wherein the regulating and control device (44) is designed to increasingly close the damping valve (32) during driving operation in order to increase a volume flow of the hydraulic fluid (20) flowing through the hydraulic pump (22), and to put the hydraulic pump (22) into the recuperation mode, so that an electrical power output by the hydraulic pump (22) during the recuperation mode increases with increasing closing of the damping valve (32). Chassis device according to claim 1 , characterized in that the hydraulic pump (22) is in fluid connection with the hydraulic cylinder (12) by means of exactly one first hydraulic line (21), wherein the hydraulic pump (22) is in fluid connection with the gas spring accumulator (25) by means of exactly one second hydraulic line (24). Chassis device according to claim 2 , characterized in that the damping valve (32) is arranged in or on a third hydraulic line (30) branching off from the first hydraulic line (21) and opening into the second hydraulic line (24). Chassis device according to one of the Claims 1 - 3 , characterized by an energy storage device (43) which stores electrical energy generated by the hydraulic pump (22). Chassis device according to one of the Claims 1 - 4 , characterized in that the hydraulic cylinder (12), the gas spring accumulator (25) and the hydraulic pump (22) form a fluidically sealed primary system (34) of the chassis device (9). Chassis device according to claim 5 , characterized in that the regulating and control device (44) is designed to regulate the primary system (34) with a passive control, a semi-active control or an active control, wherein the regulating and control device (44) controls neither the damping valve (32) nor the hydraulic pump (22) in the passive control, wherein the regulating and control device (44) controls only the damping valve (32) in the semi-active control, and wherein the regulating and control device (44) controls both the damping valve (32) and the hydraulic pump (22) in the active control. Chassis device according to claim 5 or 6 , characterized by a secondary system (41) which can be brought into fluid communication with the primary system (34) by means of a valve assembly (35). Chassis device according to claim 7 , characterized in that the valve assembly (35) is arranged between the gas spring accumulator (25) and the hydraulic pump (22). Chassis device according to claim 7 or 8 , characterized in that the valve assembly (35) can be switched with the aid of the regulating and control device (44) from a first switching state (Z1), in which the secondary system (41) is fluidically separated from the primary system (34), to a second switching state (Z2), in which the hydraulic pump (22) is fluidically separated from the gas spring accumulator (25) and the secondary system (41) is fluidically connected to the hydraulic pump (22). Chassis device according to one of the Claims 7 - 9 , characterized in that the secondary system (41) has a hydraulic accumulator (37) in which hydraulic fluid (20) is accommodated. Vehicle (1) with at least one chassis device (9) according to one of the Claims 1 - 10 . Method for operating a chassis device (9) for a wheel (5, 6) of a vehicle (1), wherein the chassis device (9) comprises a hydraulic cylinder (12) in which hydraulic fluid (20) is accommodated, a gas spring accumulator (25) in which hydraulic fluid (20) is also accommodated, an adjustable damping valve (32) which is in fluid communication with both the hydraulic cylinder (12) and the gas spring accumulator (25), a hydraulic pump (22) which is in fluid communication with both the hydraulic cylinder (12) and the gas spring accumulator (25), and a regulating and control device (44) for continuously opening and closing the damping valve (32) and for switching the hydraulic pump (22) from a pumping mode to a recuperation mode and vice versa, wherein the damping valve (32) and the hydraulic pump (22) are connected in parallel to one another, and wherein the method comprises the following steps: a) carrying out (S1) a driving operation of the chassis device (9), wherein hydraulic fluid (20) flows from the hydraulic cylinder (12) to the gas spring accumulator (25) and vice versa through the damping valve (32) and/or through the hydraulic pump (22), b) increasingly closing (S2) the damping valve (32) with the aid of the regulating and control device (44) in order to increase a volume flow of the hydraulic fluid (20) flowing through the hydraulic pump (22), and c) bringing (S3) the hydraulic pump (22) into the recuperation mode with the aid of the regulating and control device (44), so that an electrical power output by the hydraulic pump (22) during the recuperation mode increases with increasing closing of the damping valve (32). procedure according to claim 12 , characterized in that the hydraulic cylinder (12), the gas spring accumulator (25) and the hydraulic pump (22) form a fluidically sealed primary system (34) of the chassis device (9), wherein the primary system (34) is controlled by the regulating and control device (44) with a passive control, a semi-active control or an active control, wherein in the passive control neither the damping valve (32) nor the hydraulic pump (22) are controlled by the regulating and control device (44), wherein in the semi-active control only the damping valve (32) is controlled by the regulating and control device (44), and wherein in the active control both the damping valve (32) and the hydraulic pump (22) are controlled by the regulating and control device (44). procedure according to claim 13 , characterized by a secondary system (41) which can be brought into fluid communication with the primary system (34) by means of a valve assembly (35), wherein the valve assembly (35) is switched by means of the regulating and control device (44) from a first switching state (Z1), in which the secondary system (41) is fluidically separated from the primary system (34), to a second switching state (Z2), in which the hydraulic pump (22) is fluidically separated from the gas spring accumulator (25) and the secondary system (41) is fluidically connected to the hydraulic pump (22). procedure according to claim 14 , characterized in that in order to increase or reduce a vehicle height of the vehicle (1), hydraulic fluid (20) is pumped from the secondary system (41) into the primary system (34) or from the primary system (34) into the secondary system (41).

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