Hydraulic device for an electrified commercial vehicle, control device for a hydraulic device and method for operating a hydraulic device

Abstract

A hydraulic device (100) for an electrified commercial vehicle (105) comprises a hydraulic pump (125) for providing a first pressure (130), an electric motor (120) for driving the hydraulic pump (125), and a hydraulic system (145). The hydraulic system (145) has a pump interface (140) to the hydraulic pump (125) and a load interface (160) to a load (110). The hydraulic system (145) is configured to provide a load pressure (163) having a first value using the first pressure (130) in a first hydraulic state and to provide the load pressure (163) having a second value using the first pressure (130) in a second hydraulic state. A control device (170) is configured to determine a model function (205) of the hydraulic system (145) associated with a current hydraulic state using a state signal (175) representative of the current hydraulic state in order to provide a motor signal (185) for controlling a rotational speed of the electric motor (120) using the model function (205).

Description

Technical Field

[0001] The present invention relates to a hydraulic device for commercial vehicles, a control device for the hydraulic device, and a method for operating the hydraulic device. Background Technology

[0002] Mobile hydraulic systems can be constructed in different ways. However, they are essentially composed of the same main components. In some applications, the hydraulic pump in a constant-flow system always delivers the same maximum volumetric flow rate depending on the rotational speed. If both high pressure and low volumetric flow rate are required simultaneously, such as in the case of slowly lifting heavy loads with the aid of a loading crane, excess hydraulic fluid is returned to the tank. Summary of the Invention

[0003] Against this backdrop, the present invention provides an improved hydraulic device according to the independent claims, an improved control device for the hydraulic device, and an improved method for operating the hydraulic device. Advantageous designs are derived from the dependent claims and the following description.

[0004] In addition to cost reduction, the proposed solution also offers the advantage of compatibility and feasibility in electrified commercial vehicles.

[0005] This invention proposes a hydraulic device for electrified commercial vehicles. The hydraulic device includes a hydraulic pump for providing a first pressure; an electric motor coupled to the hydraulic pump to drive the hydraulic pump; and a hydraulic system. Here, the hydraulic system has a pump interface for connection to the hydraulic pump and a load interface for connection to a load, wherein the hydraulic system is configured to provide a load pressure with a first value using the first pressure in a first hydraulic state and to provide a load pressure with a second value using the first pressure in a second hydraulic state. Furthermore, the hydraulic device includes a control device configured to receive a status signal, wherein the status signal represents the current hydraulic state. The control device is configured to use the status signal to determine a model function of the hydraulic system associated with the current hydraulic state, so as to use the model function to provide a motor signal for controlling the rotational speed of the electric motor.

[0006] Commercial vehicles, such as those used for moving loads like loading cranes, may include hydraulic equipment that can be part of a load-sensing control system. This system, also known as a load pressure reporting system, is capable of identifying the type of load present. Typically, flow rates independent of load pressure can be regulated via a special control block.

[0007] In contrast to load sensing systems that regulate via sensors, valves, and additional hydraulic load reporting lines or electrical signal lines, the hydraulic device proposed herein advantageously achieves sensorless detection of load and load pressure, or pressure at the load, wherein the additional load reporting lines or electrical signal lines can detect the existing pressure difference and keep it constant. For example, the load can be a linear hydraulic cylinder. This regulation can be achieved using an electric motor, also known as an e-motor, and software algorithms in the control device.

[0008] For example, the output pressure at a hydraulic pump can be calculated using known variables of the electric motor, namely current and torque. The calculation or determination of torque may be related to the type and control of the electric motor. For instance, if a fixed displacement pump is used, the initial pressure or volumetric flow can be proportional to the rotational speed, meaning the displacement can be constant. Therefore, the initial pressure can be calculated from the rotational speed.

[0009] The hydraulic pump of the hydraulic equipment described herein is connected to the hydraulic system via a pump interface. The hydraulic system is configured to provide load pressure at a load interface to the load using a first pressure, wherein the load pressure may be related to the hydraulic state of the hydraulic system. For example, in the first hydraulic state, a control valve located in the hydraulic system may be opened, for example, based on a corresponding user input. In the second hydraulic state, for example, the control valve may be closed. Here, the hydraulic system may have other hydraulic states besides the first and second hydraulic states, depending on the complexity of the system used.

[0010] The current hydraulic state, such as a first hydraulic state, a second hydraulic state, or other hydraulic states, can be detected by a control device using corresponding status signals. The control device can use these status signals to determine a model function associated with the current hydraulic state. For example, a first model function may be associated with or be associated with a first hydraulic state, while a second model function may be associated with or be associated with a second hydraulic state. Therefore, using the information about the hydraulic state and the predefined model function transmitted via the status signals, it is possible to calculate which motor power is optimal for the load applied at the load, and to provide corresponding motor signals to control the speed of the electric motor.

[0011] The corresponding model function can be calculated, set, or selected using state signals. Accordingly, model functions associated with different states can be predetermined. Model functions can consider, for example, the valve position, efficiency, or characteristic curves of valves in a hydraulic system. Therefore, each model function can be a model of a hydraulic system for a specific, predetermined state. By modeling the hydraulic system, the sensor used to measure the current load pressure can be eliminated. Instead, the load pressure can be determined using the model function.

[0012] The hydraulic device proposed herein can be advantageously and very inexpensively implemented without additional components such as sensors, signals, and hydraulic lines. Furthermore, the system can be operated with an inexpensive fixed displacement pump instead of a more expensive variable displacement pump. Therefore, the system provides an inexpensive and variable solution for implementing load sensing functionality in commercial vehicles with electrified operation.

[0013] According to one embodiment, the control device can be configured to determine a load pressure signal representing the load pressure using a pressure signal representing a first pressure and a model function, and to provide a motor signal using the load pressure signal. For example, the first pressure can be calculated based on known electric motor information, such as the current rotational speed, and provided as a corresponding pressure signal. Simultaneously, the current load pressure can be calculated based on information from the hydraulic system, which can be provided to the control device via a status signal. The pressure difference between the current load pressure and the desired load pressure can be advantageously determined, and if necessary, the rotational speed of the electric motor can be changed to match the current load pressure to the desired load pressure. This optimizes the efficiency of the hydraulic equipment.

[0014] According to another embodiment, the hydraulic system can be configured to provide status signals to a control device. For example, the hydraulic system can be placed in a first hydraulic state, such as when a valve is open. The hydraulic system can provide this information, for example, by means of an implemented electronic unit, in the form of status signals for the control device. This has the advantage that information about the hydraulic system's status can be provided to the control device directly and without delay.

[0015] According to another embodiment, the hydraulic system may include an adjustment interface for receiving adjustment signals and is configured to use the adjustment signals to set the current hydraulic state, wherein the adjustment signals may represent signals provided by a user interface. The user interface may be, for example, a human-machine interface, such as a lever or switch, by which a user or vehicle driver can set the desired hydraulic state. Signals thus provided by the user may be detected by a control device and forwarded to the hydraulic system as adjustment signals, or may be processed by a separate electronic control unit of the hydraulic system. Therefore, the hydraulic settings desired by the user can be advantageously executed, thereby optimizing the required motor power of the hydraulic equipment.

[0016] According to another embodiment, the hydraulic pump can be configured as a fixed displacement pump. While other load sensing systems can be operated, for example, by means of a variable displacement pump, the hydraulic device proposed herein can be operated by means of a vertical pump, such that the initial pressure or volumetric flow generated by the hydraulic pump can be proportionally related to the rotational speed. Advantageously, compared to more expensive variable displacement pumps, cost savings can be achieved by using an inexpensive fixed displacement pump.

[0017] According to another embodiment, the hydraulic pump can be configured to provide a first volumetric flow, and the hydraulic system can be configured to use the first volumetric flow to provide a load volumetric flow with a first value in a first hydraulic state and to use the first volumetric flow to provide a load volumetric flow with a second value in a second hydraulic state. For example, a larger load volumetric flow can be provided in the first hydraulic state than in the second hydraulic state, wherein the load volumetric flow can be advantageously optimized for the load located at the load.

[0018] According to another implementation, the control unit can be configured to provide a motor signal for reducing the speed to a minimum using a status signal, where the status signal represents a stationary state as the current hydraulic state. Additionally or alternatively, the speed reduction can also be performed in response to a pressure signal. Therefore, if it is necessary to maintain maximum pressure in the system, where no movement should be performed simultaneously, the software can operate the electric motor at a minimum speed, and additionally or alternatively, can shut down the electric motor to advantageously save energy. The software input can be the output pressure, i.e., the torque of the electric motor, or it can be a signal from the hydraulic system, such as the position of a directional valve.

[0019] According to another embodiment, the control device can be configured to receive a load signal representing a load acting on a load, so as to provide a motor signal using the load signal. For example, in some applications, a description of the load is provided. In these cases, this information can be used to calculate hydraulic pressure or load pressure. The calculation may be related to the type of load. For example, if a sufficiently detailed description of the load is available, "feedforward" control can be used. All information can be transmitted to software. The control device can receive information about the load to achieve optimized regulation or synchronization, such as directional valves. This can advantageously and significantly improve response time.

[0020] According to another implementation, the control device may include a reference table for selecting model functions. For example, a corresponding predefined model function can be associated with each predefined hydraulic state in the reference table. This has the advantage of saving time and energy when processing information obtained from the hydraulic system and subsequently providing motor signals.

[0021] A hydraulic system can be configured to use the temperature value of the oil in the system to determine the status signal. Therefore, the model function can more accurately reflect the current state of the hydraulic system.

[0022] According to another embodiment, the hydraulic equipment can have a speed sensor for providing a speed signal representing the rotational speed of an electric motor, wherein the control device can be configured to use the speed signal to provide a motor signal. For example, if the load at the hydraulic cylinder is increased, the pressure in the hydraulic system also increases, thereby reducing the pump speed. In this case, the current torque is too small for the applied load. The speed sensor at the electric motor can provide information about the rotational speed in the form of a speed signal. Here, the control device can be configured to use the speed signal to provide a motor signal, thereby increasing the electric motor speed, for example. Correspondingly, when the load at the load decreases, the speed at the electric motor increases, i.e., it brings excessive power, so the control device can use the speed signal to cause a decrease in current. Thus, regardless of the load and usage, the desired constant speed can be advantageously achieved, thereby enabling the system to achieve higher efficiency.

[0023] According to another embodiment, the hydraulic device may have a frequency converter configured to receive motor signals and use those signals to control the rotational speed of an electric motor. For example, the frequency converter can receive motor signals from a control device and control the rotational speed accordingly; this frequency converter may also be referred to as an inverter. Advantageously, motor control can be optimized and energy can be saved using a frequency converter.

[0024] According to another embodiment, the frequency converter can be configured to operate a separate electric motor. For example, the separate electric motor can be coupled to a separate hydraulic pump for providing a separate first pressure, wherein the separate hydraulic pump can be coupled to a separate hydraulic system via a separate pump interface. Here, the separate hydraulic system can have a separate load interface for connection to a separate load and is configured to provide a separate load pressure with a first value using the separate first pressure in a separate first hydraulic state and to provide a separate load pressure with a second value using the separate first pressure in a separate second hydraulic state. Furthermore, the control device can be configured to receive a separate status signal provided by the separate hydraulic system, wherein the separate status signal can represent a separate current hydraulic state. The control device can be configured to use the separate status signal to determine a separate model function of the separate hydraulic system associated with the separate current hydraulic state, so as to provide a separate motor signal for controlling the rotational speed of the separate electric motor to the frequency converter using the separate model function. Advantageously, therefore, one frequency converter can be advantageously used for multiple electric motors and thus for multiple loads with different loads.

[0025] Furthermore, a control device for hydraulic equipment is proposed, wherein the hydraulic equipment comprises: a hydraulic pump for providing a first pressure; an electric motor coupled to the hydraulic pump to drive the hydraulic pump; and a hydraulic system having a pump interface for connection to the hydraulic pump and a load interface for connection to a load. Here, the hydraulic system is configured to provide a load pressure with a first value using the first pressure in a first hydraulic state and to provide a load pressure with a second value using the first pressure in a second hydraulic state. The control device is configured to receive a status signal, wherein the status signal represents the current hydraulic state of the hydraulic system. Furthermore, the control device is configured to use the status signal to determine a model function of the hydraulic system associated with the current hydraulic state, so as to use the model function to provide a motor signal for controlling the rotational speed of the electric motor. Advantageously, the hydraulic system, particularly the hydraulic system of commercial vehicles, can be optimized using the control device proposed herein, and matched to the load currently applied to the load.

[0026] Furthermore, a method for operating a hydraulic device is proposed, the hydraulic device comprising: a hydraulic pump for providing a first pressure; an electric motor coupled to the hydraulic pump to drive the hydraulic pump; and a hydraulic system. Here, the hydraulic system includes a pump interface for connection to the hydraulic pump and a load interface for connection to a load, and is configured to provide a load pressure having a first value using the first pressure in a first hydraulic state and to provide a load pressure having a second value using the first pressure in a second hydraulic state. Here, the method includes the steps of: receiving a status signal via a control device, wherein the status signal represents the current hydraulic state of the hydraulic system, and using the status signal to determine a model function of the hydraulic system associated with the current hydraulic state. Furthermore, the method includes the step of: providing a motor signal for controlling the rotational speed of the electric motor using the model function. Attached Figure Description

[0027] The invention will be explained in more detail by way of example with reference to the accompanying drawings. The drawings show:

[0028] Figure 1 This is a schematic diagram of a hydraulic device according to one embodiment;

[0029] Figure 2 This is a schematic diagram of a control device according to one embodiment;

[0030] Figure 3 This is a schematic diagram of a hydraulic device according to one embodiment;

[0031] Figure 4 This is a schematic diagram of a hydraulic device according to one embodiment;

[0032] Figure 5 This is a schematic diagram of a hydraulic device according to one embodiment; and

[0033] Figure 6 This is a block diagram of one embodiment of a method for operating hydraulic equipment.

[0034] In the following description of preferred embodiments of the invention, the same or similar reference numerals are used for elements shown in the various figures and that have similar functions, wherein repeated descriptions of these elements are omitted. Detailed Implementation

[0035] Figure 1 A schematic diagram of a hydraulic device 100 according to one embodiment is shown. In this embodiment, the hydraulic device 100 is disposed in an electrified commercial vehicle 105, which, by way of example, includes a loader crane (Ladekran). The commercial vehicle 105 includes a hydraulic load 110, which, by way of example, is formed as a linear hydraulic cylinder. For example, during operation, a load 115 acts on the load 110. The load 110 is used, for example, to hold or move the load 115.

[0036] The working motion of loading cranes or commercial vehicles with similar loads is characterized by a movement flow from very fast to very slow under varying load conditions. To this end, the hydraulic device 100 shown herein is used to automatically match load changes and ensure a constant operating speed of the commercial vehicle 105 by responding precisely to operator presets, thereby ensuring comfortable operation of the system. Here, the hydraulic device 100 includes an electric motor 120 coupled to a hydraulic pump 125 to drive the hydraulic pump. By way of example only, the hydraulic pump 125 in this embodiment is a fixed displacement pump, which provides a first pressure 130, also denoted as p1, in the hydraulic device 100, and a first volumetric flow 135, also denoted as Q1, by way of example only.

[0037] Hydraulic pump 125 is connected to hydraulic system 145 via pump interface 140. Various control valves 146, control blocks 147, connection lines 148, and other valves 149 are provided, only by way of example, in hydraulic system 145. These components of hydraulic system 145 can be adjusted so that hydraulic system 145 can have a first hydraulic state and a second hydraulic state. For this purpose, hydraulic system 145 in the above embodiment includes adjustment interface 150 for receiving adjustment signal 153 and is configured to set the current hydraulic state by using the adjustment signal. Here, adjustment signal 153 only exemplarily represents signal 158 provided by user interface 155. The first hydraulic state only exemplarily corresponds to a state with control valve 146 open by the user, while the second hydraulic state corresponds to a state with control valve 146 closed. In the above embodiment, hydraulic system 145 is configured to provide load pressure 163 and load volume flow 165 via load interface 160 using a first pressure 130 and a first volume flow 135 in the first hydraulic state. Here, load pressure 163 and load volume flow 165 each have a first value corresponding to the first hydraulic state. Similarly, the hydraulic system 145 is configured in a second hydraulic state to provide a load pressure 163 and a load volume flow 165, each having a second value, via a load interface 160, using a first pressure 130 and a first volume flow 135, wherein the second value in this embodiment is lower than the first value due to the control valve 146 being closed in the second hydraulic state. The load 115 applied to the load 110 can then be moved by means of the load pressure 163 and the load volume flow 165.

[0038] To enable automatic load adaptation of the electric motor 120 when the load 115 changes, the hydraulic device 100 shown herein also includes a control device 170 configured to receive a status signal 175 representing the current hydraulic state. The status signal 175 may, by way of example only, be provided by the hydraulic system 145, where the current hydraulic state corresponds to either a first hydraulic state or a second hydraulic state. The control device 170 is configured to use the status signal 175 to determine a model function of the hydraulic system 145 associated with the current hydraulic state. Furthermore, the hydraulic device 100 in this embodiment includes a speed sensor 180 configured to detect the current speed of the electric motor 120 and provide a speed signal 183 representing the speed to the control device 170.

[0039] The control device 170 is configured, by way of example only, to use a model function and a speed signal 183 to provide a motor signal 185 for controlling the speed of the electric motor 120. Here, in the embodiment described, the hydraulic device 100 includes a frequency converter 190 for receiving the motor signal 185, wherein the frequency converter 190 is configured, by way of example only, to use the motor signal 185 to control the speed of the electric motor 120.

[0040] In other words, the pressure and volumetric flow at load 115 and at load 110 can be determined without sensors using the hydraulic device 100 shown herein, or the flow rate and oil pressure after hydraulic pump 125 can be determined. In this embodiment, this problem is solved by means of electronic components, namely electric motor 120 and frequency converter 190 and control device 120 software algorithms. The first pressure 130 or output pressure at hydraulic pump 125 can be calculated using known variables, namely the current and torque of electric motor 120. The calculation or determination of torque is related to the type and control of electric motor 120. Because a fixed displacement pump is used in this embodiment, the first volumetric flow 135 is proportional to the rotational speed, i.e., the displacement is constant, so that the first volumetric flow 135 can be calculated via the rotational speed. For accurate volumetric flow values, a curve of the pump's capacity efficiency is required. To calculate the pressure at load 110, a description of the hydraulic system 145 and its included components is essential. Software-based calculations require information such as pressure loss, component efficiency, and characteristic curves of valves 146 and 149, which, according to one embodiment, are considered in a model function, wherein these characteristic curves are related to pressure, volumetric flow, oil temperature, etc. Accordingly, the model function can represent a model of the hydraulic system 145 in a specific state. Therefore, the pressure difference to be applied between the first pressure 130 and the load pressure 163 can be calculated, and the software of the control device 170 adjusts the supply to the load 110 according to the formula Q2,p2 = Q1,p1 * function (t,p,T,Q,η). Here, the function (t,p,T,Q,η) can represent the corresponding model function. Here, parameters t, p, T, Q, and η can define the current state of the hydraulic system 145. According to one embodiment, at least some of these parameters are transmitted via a status signal 175. According to one embodiment, a suitable sensor device is used to detect parameters, such as a timer for detecting time T, a pressure sensor for detecting pressure p, a temperature sensor for detecting temperature T, a flow sensor for detecting volumetric flow Q, and / or a speed sensor for detecting rotational speed η.

[0041] Figure 2 A schematic diagram of a control device 170 according to one embodiment is shown. The control device 170 shown herein corresponds to or is similar to the one previously described. Figure 1 The control device described herein. Control device 170 is configured to receive a status signal 175, the status signal representing a previous... Figure 1 The current hydraulic state of the hydraulic system described in the document.

[0042] The control device 170 includes, by way of example only, a reference table 200, by which a state signal 175 can be used to associate a corresponding model function 205 with the current hydraulic state. Alternatively, the model function may be calculated or otherwise determined using the state signal 175.

[0043] Furthermore, in this embodiment, the control device 170 is configured to receive a pressure signal 210 representing a first pressure and use the pressure signal 210 and the model function 205 to determine a load pressure signal 215 representing the load pressure. Here, in this embodiment, the load pressure signal 215 corresponds to... Figure 1 The calculated value of the load pressure described in the text.

[0044] In the described embodiment, pressure signal 210 merely represents a first pressure, which is required in the preceding... Figure 1 The electric motor described herein is reduced to a minimum speed to create a static state in the hydraulic system. In another embodiment, the status signal 175 may also represent the current hydraulic state as a static state and thus similarly require a reduction in speed. In other words, in this embodiment, it is required to maintain maximum pressure in the system while simultaneously initiating no movement. Accordingly, the software of the control device 170 is configured to operate the electric motor at a minimum speed to conserve energy. Alternatively, the electric motor may also be shut off in the static state.

[0045] In one embodiment, the control device 170 is additionally configured to receive a load signal 220, which represents a load acting on a load. A motor signal 185 can be provided using a load pressure signal 215 and a load signal 220, wherein, in response to the motor signal 185, control can be performed on a previously... Figure 1 The speed of the electric motor described in the text.

[0046] Figure 3 A schematic diagram of a hydraulic device 100 according to one embodiment is shown. The hydraulic device 100 shown herein corresponds to or is similar to... Figure 1 The hydraulic equipment described herein. Information regarding the applied load 115 is provided in the view shown here. In these cases, this information can be used to calculate the hydraulic pressure p2 or Figure 1 The load pressure described in the diagram is used. The calculation is related to the type of load 110. If sufficiently detailed specifications regarding load 115 are available, "feedforward" control can be used. All information can be transmitted to the software of control unit 170. Control unit 170 is configured to receive user-desired settings and information about load 115 from user interface 155, thus enabling optimized regulation or synchronization of the directional valves in hydraulic system 145.

[0047] Figure 4A schematic diagram of a hydraulic device 100 according to one embodiment is shown. The hydraulic device 100 shown herein corresponds to or is similar to those previously described. Figure 1 and 3 The hydraulic device described herein differs in that, in this embodiment, the frequency converter 190 is configured to control an additional electric motor 400 in addition to the electric motor 120. Here, the additional electric motor 400 is similar to the electric motor 120 coupled with an additional hydraulic pump 405, so as to... Figure 1 The hydraulic system already described drives the additional load 410. Here, in the described embodiment, the frequency converter 190, as... Figure 1 As described, it can be operated by control device 170, which is coupled to user interface 155.

[0048] Figure 5 A schematic diagram of a hydraulic device 100 according to one embodiment is shown. The hydraulic device 100 shown herein corresponds to or is similar to the previous one. Figure 1 , Figure 3 and Figure 4 The hydraulic device described herein differs in that, in this embodiment, the hydraulic device 100, in addition to the frequency converter 190, also has an additional frequency converter 500. In this embodiment, the additional frequency converter 500 controls an additional electric motor 505, which is coupled to an additional hydraulic pump 510, which is connected via... Figure 1 The hydraulic system described herein drives the additional load 515. Here, in the embodiment described, the additional frequency converter 500 can be equivalent to the frequency converter 190, which is controlled by a control device 170, which is in turn coupled to a user interface 155.

[0049] Figure 6 A block diagram of one embodiment of a method 600 for operating a hydraulic device as described in the foregoing figures is shown. Accordingly, the hydraulic device that can be operated by means of the illustrated method 600 includes a hydraulic pump, an electric motor for driving the hydraulic pump, and a hydraulic system that is pressure-loaded on the input side via the hydraulic pump and can output pressure to a load on the output side.

[0050] Method 600 includes step 605, in which a status signal indicating the current hydraulic state of the hydraulic system is received. In step 610, the status signal is used to determine a model function of the hydraulic system associated with the current hydraulic state. Furthermore, method 600 includes step 615, using the model function to provide a motor signal for controlling the speed of an electric motor.

[0051] List of reference numerals in the attached diagram:

[0052] 100 Hydraulic Equipment

[0053] 105 Commercial Vehicles

[0054] 110 load

[0055] 115 load

[0056] 120 electric motor

[0057] 125 hydraulic pump

[0058] 130 First Pressure

[0059] 135 First Volume Flow

[0060] 140 pump interface

[0061] 145 Hydraulic System

[0062] 146 Control Valve

[0063] 147 Control Block

[0064] 148 Connection Line

[0065] 149 Other valves

[0066] 150 Adjust the interface

[0067] 153 Adjust signal

[0068] 155 User Interface

[0069] 158 signal

[0070] 160 load interface

[0071] 163 Load pressure

[0072] 165 Load Volume Flow

[0073] 170 Control device

[0074] 175 Status Signal

[0075] 180 Speed ​​Sensor

[0076] 183 Speed ​​signal

[0077] 185 Motor Signal

[0078] 190 Frequency Converter

[0079] 200 Reference Table

[0080] 205 Model Functions

[0081] 210 Pressure Signal

[0082] 215 Load pressure signal

[0083] 220 Load Signal

[0084] 400 additional electric motors

[0085] 405 Other hydraulic pumps

[0086] 410 Additional load

[0087] 500 additional frequency converters

[0088] 505 Additional electric motor

[0089] 510 Additional hydraulic pump

[0090] 515 Additional load

[0091] 600 Methods for operating hydraulic equipment

[0092] 605 Receiving Steps

[0093] 610 Determine the steps

[0094] 615 provides steps

Claims

1. A hydraulic device (100) for an electrified commercial vehicle (105), wherein the hydraulic device (100) includes the following features: A hydraulic pump (125) for providing the first pressure (130); An electric motor (120) is coupled to the hydraulic pump (125) to drive the hydraulic pump (125); A hydraulic system (145) having a pump port (140) for connection to the hydraulic pump (125) and a load port (160) for connection to a load (110), wherein the hydraulic system (145) is configured to provide a load pressure (163) having a first value using the first pressure (130) in a first hydraulic state and to provide a load pressure (163) having a second value using the first pressure (130) in a second hydraulic state; and A control device (170) is configured to receive a status signal (175) representing a current hydraulic state, and the control device is configured to use the status signal (175) to determine a model function (205) of the hydraulic system (145) associated with the current hydraulic state, so as to use the model function (205) to provide a motor signal (185) for controlling the rotational speed of the electric motor (120).

2. The hydraulic equipment (100) according to claim 1, characterized in that, The control device (170) is configured to determine a load pressure signal (215) representing the load pressure (163) using a pressure signal (210) representing the first pressure (130) and the model function (205), and to provide the motor signal (185) using the load pressure signal (215).

3. The hydraulic device (100) according to any one of the preceding claims, characterized in that, The hydraulic system (145) is configured to provide the status signal (175) to the control device (170).

4. The hydraulic device (100) according to any one of the preceding claims, characterized in that, The hydraulic system (145) includes an adjustment interface (150) for receiving an adjustment signal (153) and is configured to use the adjustment signal (153) to set the current hydraulic state, wherein the adjustment signal (153) represents a signal (158) provided by the user interface (155).

5. The hydraulic device (100) according to any one of the preceding claims, characterized in that, The hydraulic pump (125) is a fixed displacement pump.

6. The hydraulic device (100) according to any one of the preceding claims, characterized in that, The hydraulic pump (125) is configured to provide a first volume flow (135), and the hydraulic system (145) is configured to use the first volume flow (135) to provide a load volume flow (165) with a first value in a first hydraulic state and to use the first volume flow (135) to provide a load volume flow (165) with a second value in a second hydraulic state.

7. The hydraulic device (100) according to any one of the preceding claims, characterized in that, The control device (170) is configured to use the status signal (175) to provide the motor signal (185) for reducing the rotational speed to a minimum value, wherein the status signal represents a stationary state as the current hydraulic state.

8. The hydraulic device (100) according to any one of the preceding claims, characterized in that, The control device (170) is configured to receive a load signal (220) representing a load (115) acting on the load (110) in order to provide the motor signal (185) using the load signal (220).

9. The hydraulic device (100) according to any one of the preceding claims, characterized in that, The hydraulic system (145) is configured to determine the status signal (175) using a temperature value that displays the oil temperature of the hydraulic system (145).

10. The hydraulic device (100) according to any one of the preceding claims, having a speed sensor (180) for providing a speed signal (183) representing the speed of the electric motor (120), wherein the control device (170) is configured to provide the motor signal (185) using the speed signal (183).

11. The hydraulic device (100) according to any one of the preceding claims, having a frequency converter (190) configured to receive the motor signal (185) and use the motor signal (185) to control the rotational speed of the electric motor (120).

12. The hydraulic equipment (100) according to claim 11, characterized in that, The frequency converter (190) is configured to control another electric motor (400).

13. A control device (170) for a hydraulic device (100), the hydraulic device comprising: a hydraulic pump (125) for providing a first pressure (130); an electric motor (120) coupled to the hydraulic pump (125) to drive the hydraulic pump (125); and a hydraulic system (145) having a pump interface (140) for connection to the hydraulic pump (125) and a load interface (160) for connection to a load (110), wherein the hydraulic system (145) is configured to provide a load having a first value using the first pressure (130) in a first hydraulic state. Pressure (163) and the first pressure (130) are used in a second hydraulic state to provide a load pressure (163) with a second value; wherein the control device (170) is configured to receive a status signal (175) representing the current hydraulic state of the hydraulic system (145), and wherein the control device is configured to use the status signal (175) to determine a model function (205) of the hydraulic system (145) associated with the current hydraulic state, so as to use the model function (205) to provide a motor signal (185) for controlling the rotational speed of the electric motor (120).

14. A method (600) for operating a hydraulic device (100), the hydraulic device comprising: a hydraulic pump (125) for providing a first pressure (130); an electric motor (120) coupled to the hydraulic pump (125) to drive the hydraulic pump (125); and a hydraulic system (145) having a pump interface (140) for connection to the hydraulic pump (125) and a load interface (160) for connection to a load (110), wherein the hydraulic system (145) is configured to provide a load pressure (163) having a first value using the first pressure (130) in a first hydraulic state and to provide a load pressure (163) having a second value using the first pressure (130) in a second hydraulic state; wherein the method (600) comprises the following steps: A status signal (175) is received (605) by the control device (170), wherein the status signal (175) represents the current hydraulic state of the hydraulic system (145). The model function (205) of the hydraulic system (145) associated with the current hydraulic state is determined (610) using the state signal (175); and The model function (205) is used to provide (615) a motor signal (185) for controlling the rotational speed of the electric motor (120).

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