Hydrostatic drive

Hydrostatic drive technology field

[0001] The present invention relates to a hydrostatic drive device according to the preamble of claim 1.

Background technique

[0002] The hydrostatic drive device is used to drive at least one hydrostatic consumer (Verbraucher). Such a hydrostatic drive device can be installed on a mobile work machine, wherein at least one of the hydrostatic consumers can be a driving motor and is provided with another static, for example, for work equipment of the mobile work machine. Hydraulic consumer. [0003] According to the prior art, a hydrostatic drive device can recover energy through the power train during the braking or deceleration of the consumer or the descent of the work equipment. The energy recovery here is reactive or predetermined and cannot be adapted and therefore cannot be optimized. The influencing parameters are usually (on average) included in the energy recovery design, but are variable in daily operation. The relevant parameters for energy recovery can no longer be changed during operation.

Summary of the invention

[0004] In contrast, the task of the present invention is to propose a hydrostatic drive device for which the energy recovery of energy is optimized.

[0005] This task is solved by a hydrostatic drive having the features of claim 1.

[0006] The claimed hydrostatic drive has at least one hydrostatic pump and at least one hydrostatic consumer, which can be supplied via the pump. In addition, a device for recovering at least a part of the braking energy, deceleration energy, or potential energy of the consumer is provided. According to the invention, the device has a software component or an electronic control unit, which is designed to control the energy recovery in a variable manner and based on at least one detected influencing parameter.

[0007] The relevant influencing variables are detected, for example, by means of temperature sensors, pressure sensors, swing angle sensors, position sensors and/or acceleration sensors for components of the hydrostatic drive device.

[0008] The influencing parameters are analyzed in order to optimize the energy recovery itself, or to optimize the switching process between motor-type operation and generator-type operation.

[0009] The strategy of energy recovery is matched based on the various influencing parameters, and therefore the energy recovery process can be particularly relevant to energy efficiency and also to operating comfort, the time requirement when switching at the beginning or the end of energy recovery, and the energy recovery process. After the end, the dynamics of the power output, the power capacity and durability of the components, and the service life of the hydrostatic drive are optimized.

[0010] The more influencing parameters that are detected and included, the better an optimization goal can be achieved or the multiple mentioned optimization goals can be achieved .

[0011] When the energy recovery is self-learning, the energy recovery performed by the electronic control unit is particularly advantageous with regard to the above-mentioned optimization scheme.

[0012] In a particularly effective improvement scheme, when necessary, through an effective learning algorithm, the energy recovery can be controlled predictably by the electronic control unit.

[0013] Here, as an influencing parameter that is easy to detect in the device technology, the operating medium temperature and/or the operating medium pressure

It can be included through the corresponding sensors already mentioned above.

[0014] The hydrostatic drive device according to the present invention can be configured as a travel drive device. For the travel drive device, one of the consumer or the consumer is a travel motor, and the travel motor can be used in braking operation. As a pump. This driving device can be installed in a mobile work machine. In this case, there is often a lot of braking and deceleration energy available, so effective recovery is very important.

[0015] The relevant influencing parameter is detected for the mobile working machine involved, for example, via a positioning system (for example GPS) and/or an acceleration sensor.

[0016] As an influencing parameter included according to the present invention, the driver's behavior and/or the selected driving mode of the driver can also be used.

[0017] The consumer or one of the consumers may form the working equipment of a mobile working machine, wherein the recovered braking energy is caused by inertia (for example, when braking the rotary drive device of the upper body of the excavator (Oberwagen) ) Or generated by positional potential energy (for example, when the boom of an excavator or the bucket of a wheel loader is lowered).

[0018] Work tasks and/or positions of consumers or work equipment (by means of position sensors and/or acceleration sensors) can be included as included influencing variables.

[0019] The material to be processed or to be turned (for example by means of a camera) can be included as an influencing variable to be included.

[0020] The selected operating mode and/or operator behavior can be included as an influencing parameter to be included. To this end, position sensors and/or acceleration sensors can be used on joysticks, accelerator pedals, brake pedals and/or inch pedals.

[0021] Environmental influences, such as the ambient temperature (with the help of temperature sensors) and/or the surrounding topology (for example, with the help of cameras, radars, lidars and/or digital map materials combined with positioning systems (such as GPS)) are used as the basis for this The influencing parameters included in the invention can also be included.

[0022] Braking energy or deceleration energy is, for example, caused by the inertia of a traveling mobile work machine (by a traveling motor acting as a pump) or by the inertia of a rotating upper car body (by the rotation of the excavator acting as a pump). Motor) or generated by the positional potential energy of the loaded bucket (for example, by the lifting cylinder of an excavator or a wheel loader).

[0023] According to the first principle, energy recovery refers to recovery.

[0024] Therefore, it is particularly simple in terms of device technology that braking energy or deceleration energy can be stored in a hydraulic accumulator.

[0025] The pump of the hydrostatic drive device according to the invention is preferably designed to be driven by a primary drive device configured as an internal combustion engine or an electric motor.

[0026] In the case of an electric motor, braking energy can be converted into electrical energy by a pump operating as a motor and an electric motor operating as a generator and stored in an electrical storage.

[0027] In the case of an internal combustion engine, before the end of the energy recovery or at the latest before the end of the immediately following throttle operation (Drosselbetrieb), the internal combustion engine can be adjusted to the optimal operating point for the next power output. superior. Here, for example, the rotation speed can be increased.

[0028] According to the second principle, energy recovery refers to regeneration.

[0029] Then, the recovered braking energy or deceleration energy is directly supplied to another consumer of the hydrostatic drive device.

Description of the drawings

[0030] An embodiment of a hydrostatic drive device according to the present invention with different strategies for energy recovery is shown in the drawing. It shows: Fig. 1 shows an embodiment of the hydrostatic drive device according to the present invention; Fig. 2 shows a first strategy for recovering energy using the hydrostatic drive device of Fig. 1; Fig. 3 shows A second strategy for recovering energy using the hydrostatic drive device of FIG. 1 is presented; and FIG. 4 shows a third strategy for recovering energy using the hydrostatic drive device of FIG. 1.

Detailed ways

[0031] FIG. 1 shows an embodiment of a hydrostatic drive device according to the present invention, which is installed in a mobile work machine that is not shown in detail. The primary drive device 1 (which can be a diesel engine or an electric motor) drives a hydrostatic pump 2 that is adjustable or non-adjustable in terms of delivery volume for supplying the consumer 4 and one or more additional pumps for other purposes. Work function or pump 6 for auxiliary unit.

[0032] The pump 2 sucks oil from the tank 8 and delivers the oil to the consumer 4 through a Ventilblock 10 having a throttle valve. The temperature sensor 12 is arranged in the tank 8.

[0033] The electronic control unit 14 is connected to the primary driving device 1, the pump 2, the valve block 10, the temperature sensor 12, and the sensor system 16 via signal lines. In the illustrated embodiment, the sensor system 16 has a position sensor and a device (such as a camera) for detecting the surrounding topology. In addition, the sensor system 16 may also have an acceleration sensor or one of the other sensors mentioned herein. In particular, the sensor system 16 in the illustrated embodiment has a plurality of pressure sensors, which are of course arranged in pressure-loaded components, such as the pump 2, the valve block 10, the consumer 4, the tank 8 or the pipe arranged between them. On the way.

[0034] FIG. 2 shows a first strategy for recovering energy using the hydrostatic drive device of FIG. 1. Here, consideration is given to the influence of the parameter operating medium temperature, which is detected by the temperature sensor 12 in the tank 8. In this strategy, the energy recovery is suspended (aussetzen) for such a long time until the oil reaches the optimal operating temperature via the valve block 10 by throttling operation. Therefore, the cold start characteristics of the hydrostatic drive are optimized. Here, this state indicates whether energy recovery is required or whether to perform throttling operation instead.

[0035] FIG. 3 shows a second strategy for energy recovery based on the hydrostatic drive device of FIG. 1. Consider the surrounding topology and location of the influencing parameters. To this end, the sensor system 16 has a position sensor and a device (for example, a camera) for detecting the surrounding topology. Operating equipment drops, and potential energy is recovered here. Before the work equipment hits the ground, the moment of impact is predicted, that is, pre-calculated. Therefore, the energy recovery process may have ended shortly before hitting the ground.

[0036] Therefore, necessary switching processes in the power train can be initiated in advance, and these switching processes may require a limited duration. This achieves more uniform operating characteristics. Shift shocks (Schaltruck), pressure peaks or traction interruptions are reduced. The mentioned switching process can be the swing of the pump 2 (urchschwenken) or a change in the direction of rotation.

[0037] FIG. 4 shows a third strategy for using the hydrostatic drive device of FIG. 1 to recover energy. The topology and location of the surrounding parameters are also considered here. As in the second strategy, the end time of energy recovery is predicted, that is, calculated in advance. The power train must therefore be converted from generator-type operation to motor-type operation and output power.

[0038] In order to improve the dynamic and response characteristics of the power train immediately after switching, the primary drive device 1 configured as an internal combustion engine is "prestressed" in order to be able to react more quickly to future load requirements. For this purpose, the corresponding status is transmitted to the motor controller of the internal combustion engine. When the state changes from energy recovery to throttling operation, take the pre-prepared method

Formula to match (for example, increase) the speed and boost pressure of the internal combustion engine.

[0039] The present invention discloses a hydrostatic drive device having at least one hydrostatic pump 2 for supplying at least one hydrostatic consumer 4, and the hydrostatic drive device has A device for recovering at least a part of the energy output by the consumer. The device has an electronic control unit 14 or at least one software component with which the energy recovery can be variably controlled and in this case based on at least one detected influencing parameter. To this end, the device also has at least one sensor 16, a camera or an operating element that detects influencing variables.

[0040] List of Reference Signs

1Primary drive pump

4 Consumer

6 another pump(s)

8 storage tanks

10 valve block

12 Temperature sensor control unit

16 sensor system.