Drive device

Abstract

The utility model relates to a driving device which is provided with an electric hydraulic driver (10) and a hydraulic auxiliary system (12), the hydraulic auxiliary system generates auxiliary torque, and the auxiliary torque counteracts main torque of the electric hydraulic driver (10) when needed.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of driving equipment, in particular for the driving equipment of mobile working machine. BACKGROUND

[0002] It is known from EP 3 569 775 B1 a hydraulic assembly with a variable pump, which can be driven by an internal combustion engine of a motor vehicle, wherein a creep valve is arranged at or in a working line of the hydraulic assembly, through which the pressure medium delivered by the variable pump can be guided to a creep throttle, which has a fixed cross section, and wherein the pump pressure or the pump volume flow is open-loop controllable or closed-loop controllable in the creep operation. With the pump volume flow and the pressure drop at the fixed creep throttle, an open-loop controllable or closed-loop controllable loss power is obtained, and thus an open-loop controllable or closed-loop controllable additional brake torque for the hydraulic assembly in the creep operation is obtained.

[0003] It is known from EP 2 399 861 B1 a hydrostatic drive system of a mobile working machine, in particular of a ground conveyor vehicle, having a working hydraulic system and a hydraulic pump for supplying the working hydraulic system, which is driven by a drive machine, in particular an internal combustion engine, and is configured as a variable pump with a variable delivery volume. Here, a delivery line leading from the pump to the working hydraulic system is provided with a pressure balance, which is configured as an input pressure balance of the working hydraulic system and is arranged in a return line branching off from the delivery line to a reservoir and is configured as a control valve having a closed position and a through-flow position, which is throttled in an intermediate position, wherein the pressure balance is loaded in the direction of the through-flow position by the delivery pressure of the pump present in the delivery line and in the direction of the closed position by a spring and by the maximum load pressure of an actuated consumer of the working hydraulic system, and wherein a heat exchanger device is arranged in the return line for cooling the pressure medium of the drive system, wherein the pressure medium volume flow flowing through the heat exchanger device can be adapted to the cooling power requirement of the drive system by varying the delivery volume of the variable pump. By using the variable pump, the delivery volume of the variable pump can be varied and thus adapted independently of the rotational speed of the drive machine driving the pump. By correspondingly increasing or reducing the delivery volume of the variable pump, here, in the return line, a high pressure medium flow for the through-flow of the heat exchanger device can be provided in the case of a high cooling power requirement, or the high pressure medium flow can be reduced in the case of a low cooling power requirement.

[0004] Furthermore, electric drives of conventional design are known, in which the present torque of 100% is generated by the electric motor installed for driving, or, during braking processes, is intercepted or rather fed back into an energy store, preferably in the form of a battery, as long as no separate service brake is present. In particular, the process of braking can lead to the situation in which more energy is recovered for the system than the system can absorb in the specific operating state. If the energy absorption capacity of the storage, preferably in the form of a battery, or the heat dissipation capacity of the inverter or the motor is not sufficient, the present excess energy can lead to damage or rather thermal overload of the present drive components. The drive systems freely available on the market today can only conditionally cope with this situation. While the excess electrical energy fed back can be limited between the electric motor, the inverter and the storage medium by means of a so-called brake chopper and thereby the storage medium is protected; in this case, thermal overload of the electric motor cannot be reliably ruled out. In the event of such an overload, the electric motor is usually changed into a so-called De-Rating mode, in which only a part of the torque can be applied or absorbed. This leads to the fact that the drive system can only be braked insufficiently and must be directly changed into an emergency stop mode for safety reasons. Invention content

[0005] Starting from this prior art, it is the task of the present invention to specify a solution which, compared thereto, is improved and which contributes to avoiding the described disadvantages.

[0006] To this end, the invention proposes a drive device, wherein the drive device has an electro-hydraulic drive and a hydraulic auxiliary system, which generates an auxiliary torque, which, if necessary, counteracts the main torque of the electro-hydraulic drive.

[0007] The drive device equipped with an electro-hydraulic drive and with a hydraulic auxiliary system according to the invention can be realized in such a way that an auxiliary torque can be generated, which, if necessary, counteracts the main torque of the electro-hydraulic drive. By means of the hydraulic auxiliary system, which is preferably configured in the form of a hydraulic machine assembly, a defined torque is intentionally applied to the electro-hydraulic drive, which counteracts the undesired, externally applied torque formed by the hydraulic and / or mechanical load, as a result of which the mechanical and thermal load of the drive is reduced and an overload of the components and a de-rating of the electric motor can be avoided. In this way, a drive is realized which is available at all times and which excludes unwanted interruptions of the working process as they can occur in today's solutions.

[0008] In this preferred arrangement, the assistance torque of the assistance system is implemented by means of an adaptation of the hydraulic pressure by means of a preferably controllable hydraulic impedance. If, in the case of a braking operation, a specific external torque of hydraulic or mechanical nature is applied to the main drive in the form of an electro-hydraulic drive, this external torque can be counteracted by means of a setting of the impedance of the device. Here, possible variants of the adaptation are: fixed setting, discrete, proportional, open-loop controlled or closed-loop controlled.

[0009] In another preferred embodiment of the drive device according to the application, it is provided, preferably in the case of an associated inverter and / or a battery for powering the electric motor, that a temperature regulation of the electric motor is carried out by means of an assistance torque. This is carried out by means of an adaptation of the hydraulic pressure by means of a fixed or adjustable impedance, which is controlled by means of an electronic control unit if necessary.

[0010] The temperature regulation of the electric motor together with the inverter can be carried out by means of

[0011] - inverter and motor performance data as input variables (temperature, rotational speed, current, torque...) and / or

[0012] - machine performance data as input variables (speed, direction, up / down, load...) and / or

[0013] - control signals, for example joystick control signals, as input variables

[0014]

[0015] In another particularly preferred embodiment of the drive device according to the application, the electro-hydraulic drive has a hydraulic pressure supply, for example in the form of a constant hydraulic pump, which is coupled by means of a power train to the driven side of the electric motor and by means of a further power train to the drive side of an assistance system which generates an assistance torque. In this way, by means of a discrete connection or a proportional regulation, a temperature regulation of the electric motor together with the inverter is achieved by means of a reduction of the torque at the main drive shaft between the electric motor and the hydraulic drive of the mechanical-hydraulic component. Alternatively, it is also possible to use a transmission mechanical component with a transmission ratio.

[0016] ​In a further preferred embodiment of the drive device according to the application, the auxiliary system for generating an auxiliary torque has a further pressure supply device, preferably in the form of a further constant hydraulic pump, which, by means of the further power train of the pressure supply device, is drivable to generate a delivery volume flow which is at least partially guided through a hydraulic resistance. In this way, a universally usable device is realized in a particularly cost-advantageous manner for minimizing the thermal load of the electro-hydraulic drive and reliably protecting the energy store, preferably in the form of a battery, by means of a reduction of the generated electric motor torque. There is no comparable solution in the prior art.

[0017] In a specific embodiment, the auxiliary torque of the auxiliary system is realized by means of an adaptation of the hydraulic pressure through a hydraulic resistance.

[0018] In a specific embodiment, the electric motor is temperature-regulated by means of the auxiliary torque.

[0019] In a specific embodiment, the electro-hydraulic drive has a hydraulic pressure supply device which is coupled to the driven side of the electric motor by means of a power train and to the drive side of the auxiliary system for generating the auxiliary torque by means of a further power train.

[0020] In a specific embodiment, the auxiliary system for generating the auxiliary torque has a further pressure supply device which, by means of the further power train of the pressure supply device, is drivable to generate a delivery volume flow which is at least partially guided through the hydraulic resistance.

[0021] In a specific embodiment, the hydraulic resistance generates a pressure drop on the fluid output side of the further pressure supply device, which exerts a corresponding auxiliary torque by means of the further power train of the pressure supply device.

[0022] In a specific embodiment, the hydraulic resistance is adjustable by means of a control device, which is controllable by a motor controller, which obtains sensor data from the electric motor by means of a sensor device.

[0023] In a specific embodiment, the electric motor is supplied with electrical energy by at least one battery.

[0024] In a specific embodiment, for the purpose of charge capacity regulation, a corresponding battery is connected to the motor controller.

[0025] In a specific embodiment, the hydraulic resistance is controllable.

[0026] In one embodiment, the electric motor is temperature-regulated by means of the auxiliary torque in the case of an associated inverter and / or a battery for supplying the electric motor.

[0027] In one embodiment, the hydraulic pressure supply device is in the form of a constant hydraulic pump.

[0028] In one embodiment, the further pressure supply device is in the form of a further constant hydraulic pump.

[0029] In one embodiment, the electric motor is controllable by means of a motor controller.

[0030] In one embodiment, the battery outputs its current to the inverter of the electric motor. BRIEF DESCRIPTION OF DRAWINGS

[0031] In the following, the drive device according to the application is explained in more detail by means of embodiments according to the drawings. Here, the principle and not to scale illustrations show, Figure 1 The main mechanical, hydraulic and electrical components of the drive device are shown in the form of a circuit diagram. DETAILED DESCRIPTION

[0032] In Figure 1 The drive device shown in its main components in Fig. 1 has an electro-hydraulic drive 10 which interacts with a hydraulic auxiliary system 12. The auxiliary system 12 is able to generate an auxiliary torque which, if necessary, counteracts the main torque of the electro-hydraulic drive 10, as will be explained in more detail below. Furthermore, the drive device has an electric motor 14 as part of the drive 10 which interacts with an inverter 16 which, in turn, is connected via paths Al, A2 to an energy store in the form of a battery 18. Furthermore, the inverter 16 is coupled via suitable paths Bl, B2 to the electric motor 14. The electric motor 14 drives a drive shaft 22 in the usual manner via a driven shaft 20 in order to drive a main drive 23 which is part of the electro-hydraulic drive 10. To this end, the driven shaft 20 and the drive shaft 22 are connected to one another via a coupling location 24. Furthermore, the main drive 23 drives a further driven shaft 26 which is connected via a further coupling location 28 to a further drive shaft 30 for driving the auxiliary system 12 or an associated auxiliary drive 31. As the arrow illustrations show, all shafts 20, 22, 26, 30 rotate in the same direction.

[0033] Driven by the electric motor 14, the main drive 23 delivers fluid, such as a hydraulic medium, in a closed or open hydraulic circuit 32, which is only partially shown in the figure. The main delivery direction of the main drive 23 is indicated by arrows D3 and D4, and arrows also indicate the delivery direction within the circuit 32. In this respect, the main drive 23 is constructed as a delivery pump device and is subjected to [unclear - possibly a specific force or condition] on the input side. Figure 1 The load is symbolically indicated by arrow 34. The corresponding load indicated by arrow 34 is received on the output side of the auxiliary drive 31, which is part of the hydraulic auxiliary system 12. In this respect, the auxiliary drive has the load loaded on its output side E3.

[0034] Furthermore, the drive unit as a whole includes a controller 36, also known in controller terminology as an ECU (Electronic Control Unit). This controller 36 is connected to the inverter 16 via control lines G5 and G6, and to a storage device in the form of a battery 18 via additional control lines G7 and G8. Additionally, a temperature monitoring device 38 is connected to the controller 36 on the input side via a measurement data line G4, thereby transmitting the current operating temperature of the electric motor 14, detected by the temperature monitoring device, to the controller 36. An additional control line G3 is used to control the electric motor from the controller 36.

[0035] An auxiliary drive 31, in the form of a hydraulic pump, is driven by the main drive 23 via shafts 26 and 30 and coupling position 28, and is connected via its input side E2 to supply line c, which draws fluid from tank 40. The auxiliary drive 31, in the form of a delivery pump, then outputs fluid with a predetermined volume and pressure to supply circuit f, which may be part of the overall hydraulic circuit 32. At a predetermined branch position 42 in supply circuit f, preferably directly after the output side E3 of the auxiliary drive 31, it is connected as a whole to a bypass line d with hydraulic resistance marked 44, according to… Figure 1 As illustrated, fluid flows from the bypass line d side through the hydraulic impedance between interfaces F1 and F2 at the input or output side of impedance 44. A discharge line e is connected at the output side of impedance 44 and therefore at interface F2, through which fluid can, for example, be returned to tank 40 (not shown).

[0036] In the embodiment shown, the hydraulic resistance 44 is formed by a proportionally electrically actuatable regulating throttle 46, wherein an actuating magnet 48 is provided for actuating the regulating throttle 46, which actuating magnet can be actuated by the control unit (ECU) 36 via a control line Gl. Instead of the regulating throttle 46, further resistances not shown can be used, for example in the form of a nozzle, a fixed throttle, a mechanically settable throttle, a pressure-limiting valve, a digitally electrically actuatable fixed throttle, a digitally electrically actuatable pressure-limiting valve, a proportionally electrically actuatable pressure-limiting valve, etc. In addition to the use of various types of valves, it is also possible to generate the hydraulic resistance 44 by means of a hydraulic storage device, for example a hydraulic accumulator (not shown).

[0037] Finally, it should also be mentioned that so-called machine performance data, such as speed, upward / downward direction, load, etc., are transmitted to the control unit 36 by means of suitable detection means 50.

[0038] With the drive device according to the application, a device is realized which can be universally used for minimizing the thermal load of an electric drive in the form of an electric motor 14, and which, in addition, simultaneously realizes a protection of a storage device in the form of a battery 18 here, and more precisely in such a way that the motor torque at the main drive 23 is reduced by means of the auxiliary drive 12 and its associated auxiliary drive 31 and hydraulic resistance 44. In this way, a device for adapting the temperature management of an electric drive 10 is realized, which is preferably used in electrically driven mobile or quasi-mobile working machines. The hydraulic auxiliary system 12 is coupled to the main drive 23 by means of a connection or coupling element 28, as already explained. By means of a fixedly set or adjustable hydraulic resistance 44, a certain pressure drop can be generated in the hydraulic circuit in the form of a supply circuit f at the output side E3 of the auxiliary drive 31. This pressure drop in turn generates a certain auxiliary torque in the further drive shaft 30 in the form of a mechanical hydraulic component of the auxiliary system 12, which further drive shaft serves as the so-called auxiliary drive shaft of the device. The auxiliary torque required for supporting the main drive 23 is then transmitted to the main drive shaft, i.e. to the further driven shaft 26, by means of the further coupling location 28 as a connection element. The further main drive shaft or drive shaft 22 is mechanically coupled to the motor driven shaft 20 here by means of the connection location 24. If the resistance is changed by means of the hydraulic resistance device 44 on the output side E3 of the auxiliary drive 31, the auxiliary torque T at the further drive shaft 30 for supporting the electric motor 14 changes. It applies here that the torque T at the driven shaft 20 of the electric motor 14 is equal to the torque at the further driven shaft 26 minus the torque at the further drive shaft 30. The relationship therefore also applies that the torque at the further driven shaft 26 is equal to the torque at the drive shaft 22 for the main drive 32.

[0039] If now in the case of a braking operation a specific external torque of hydraulic or mechanical nature is applied to the main drive 23, this can be counteracted by means of the hydraulic impedance 44 of the drive device, which has been described above. Thus, there is the possibility to temperature-regulate the electric motor 14 and the inverter 16 by adapting the auxiliary torque at the further drive shaft 30 of the auxiliary drive 31, by adapting the hydraulic pressure on the output side E3 of the auxiliary drive 31 by means of the fixed or adjustable impedance 44, which is preferably operated by means of an electronic control unit in the form of the controller 36. Furthermore, there is the possibility to temperature-regulate the electric motor 14 together with the associated inverter 16 by means of a discrete connection or a proportional adaptation of the torque in the respective main drive shaft 22, 26 in the form of the mechanical hydraulic components of the main drive 23. Alternatively, the torque reduction can also be achieved by means of a transmission ratio by means of mechanical transmission components, which are not shown.

[0040] In addition to the possibility of an adaptive torque delay for the electric motor 14, a charge capacity regulation of the storage device, preferably in the form of the battery 18, can also be carried out in accordance with so-called performance data of the storage medium, such as state of charge, temperature, load, with the drive device according to the application.

[0041] In summary, a creeper solution is achieved with the drive device according to the application, which is particularly suitable for use in electric machines. In the case of every type of fault on the electric drive side (overheating of the electric motor 14, collapse of the inverter 16, overload of the lines Al, A2, Bl, B2, etc., full charge of the battery 18), the machine can still be reliably braked to a defined maximum speed or even stopped up to a standstill using the hydraulic auxiliary system 12 described.

[0042] In particular, machines with hydrostatic travel drives in a closed circuit generally dispense with a separate service brake and braking is achieved more or less by adjusting the delivery pump, which then regulates the machine. This is generally not a problem when using a diesel engine; in electric machines, however, it is a problem. Here, the problems already described can occur, which cannot be solved with conventional arrangements of the hydraulic powertrain.

[0043] In a specific solution, the auxiliary drive 31 of the auxiliary system 12 is used on the mechanically connected powertrain for the main drive 23 in order to be able to establish a defined braking torque when required or in the event of a fault. For this purpose, a hydraulic impedance 44 is incorporated into the working connection on the output side E3 of the auxiliary drive 31, preferably in the form of a proportional pressure-limiting valve.

[0044] By loading with a defined current on the electric motor side, the pressure and thus the braking torque follows the input signal. Preferably, a counter pressure limiting valve is used as hydraulic impedance 44 in order to guarantee the maximum braking power in the event of a power failure.

[0045] By means of a performance management system, preferably implemented in the controller 36, the "health status" of the main drive 23 is continuously monitored. If it is determined that the battery 18, the electric motor 14,... requires a certain unloading, the retarder function (7-50 Nm) is applied accordingly proportionally and delayed in a braking manner.

[0046] Due to the modular construction of the drive device according to the application, there is also the possibility of retrofitting the drive device into components already present at the respective working machine.

Claims

1. A driving device, characterized in that, The drive device has an electro-hydraulic drive (10) and a hydraulic auxiliary system (12) that generates an auxiliary torque that, when needed, counteracts the main torque of the electro-hydraulic drive (10) and, by means of the auxiliary torque, regulates the temperature of the electric motor (14).

2. The driving device according to claim 1, characterized in that, The auxiliary torque of the auxiliary system (12) is achieved by adapting the hydraulic pressure through the hydraulic resistance (44).

3. The driving device according to claim 1, characterized in that, The electro-hydraulic drive (10) has a hydraulic pressure supply device (23) which is coupled to the driven side (20) of the electric motor (14) via a power transmission system (22) and to the drive side (30) of the auxiliary system (12) that generates the auxiliary torque via another power transmission system (26).

4. The driving device according to claim 3, characterized in that, The auxiliary system (12) that generates the auxiliary torque has an additional pressure supply device (31) that can be driven by the additional power transmission system (26) of the pressure supply device (23) to generate a delivery volume flow that is at least partially guided through the resistance (44) of the hydraulic pressure.

5. The driving device according to claim 4, characterized in that, The hydraulic resistance (44) creates a pressure drop on the fluid output side (E3) of the additional pressure supply device (31), which applies a corresponding auxiliary torque through the additional power transmission system (26) of the pressure supply device (23).

6. The driving device according to claim 2, characterized in that, The resistance (44) of the hydraulic pressure can be adjusted by means of a control device that can be operated by a motor controller (36) that obtains sensor data from the electric motor (14) through a sensor device (38).

7. The driving device according to any one of claims 1 to 6, characterized in that, The electric motor (14) is powered by at least one battery (18).

8. The driving device according to claim 6, characterized in that, For charging capacity adjustment, the corresponding battery (18) is connected to the motor controller (36).

9. The driving device according to claim 2, characterized in that, The resistance of the hydraulic pressure is controllable.

10. The driving device according to claim 2, characterized in that, In the case of an associated inverter (16) and / or a battery (18) that powers the electric motor (14), the temperature of the electric motor (14) is regulated by means of the auxiliary torque.

11. The driving device according to claim 3, characterized in that, The hydraulic pressure supply device is in the form of a constant hydraulic pump.

12. The driving device according to claim 4, characterized in that, The additional pressure supply device takes the form of an additional constant hydraulic pump.

13. The driving device according to claim 6, characterized in that, The electric motor can be controlled by a motor controller (36).

14. The driving device according to claim 7, characterized in that, The battery outputs its current to the inverter (16) of the electric motor (14).

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