MOBILE WORK MACHINE, IN PARTICULAR WHEEL LOADERS, WITH AN ELECTRIC DRIVE MOTOR

Description

[0001] The invention relates to a mobile work machine, in particular a wheel loader, telescopic loader, excavator, tractor or the like, having a vehicle frame and a drive unit for driving at least one drive wheel or a drive chain, wherein the drive unit comprises at least one electric motor and at least one electrical energy storage device for storing electrical energy for the electric motor, according to the preamble of claim 1. State of the art

[0002] Mobile work machines, especially wheel loaders, telehandlers, excavators, tractors, or the like, with a vehicle frame and a drive unit for driving at least one drive element such as a wheel or track, are now usually powered by a refillable fuel. Diesel-powered vehicles are primarily used today. Electric-powered machines are also now in use.

[0003] Except for wheel loaders with large buckets on the lifting arm, modern mobile machines often feature detachably connectable work tools, e.g., which are held or released using so-called "quick couplers" or "interchangeable plates." In addition to "passive" work tools such as shovels, bale forks, or the like, there are also work tools such as brooms, mulchers, grapple arms, grab buckets, lifting forks, or the like, which accordingly feature an "active" or power-driven tool.

[0004] When operating mobile work machines, particularly wheel loaders, telehandlers, excavators, tractors, or similar, with high power requirements and energy supply from an energy storage device, the energy storage device may heat up, potentially exceeding the maximum permissible operating temperature of the energy storage device. For example, high power consumption and output can cause the energy storage device to heat up itself. Furthermore, the energy storage device can be further heated by ambient heating, for example, by the working heat of the mechanical system.

[0005] Heating of the energy storage device can have various adverse consequences. For example, the heating can reduce the energy storage device's efficiency in power delivery and absorption. The high operating temperature can also cause permanent damage to the energy storage device. Furthermore, if the maximum temperature is exceeded, the energy storage device may be destroyed and thus rendered unusable.

[0006] Furthermore, if the maximum permissible operating temperature of the energy storage device is exceeded, the operator or driver of the mobile machine may also be injured. Potential hazards include the risk of fire or explosion from the overheated energy storage device. There may also be a risk of burns and / or poisoning from the gases generated or escaping from this process or from contact with chemicals from a damaged energy storage device.

[0007] Another disadvantage is the high costs that must be taken into account when replacing the energy storage device due to impairment or damage.

[0008] This is also why modern electrical energy storage devices, such as lithium-ion batteries or similar devices, are equipped with a costly and structurally complex electronic control unit or monitoring system. This is intended to ensure optimal charging and discharging cycles and / or to avoid or at least minimize any impairment of the electrical energy storage device.

[0009] A work machine is known from the publication US 2013 / 0075 171 A1, in which a cooling air stream is drawn from the "battery" through a pipe by a fan and flows into the engine compartment or to an inverter, and finally to the electric drive motor. The warm exhaust air is expelled from the engine compartment through an opening by a second, larger fan. Disadvantages of this prior art are the two fans required and the complex cooling air system, with only a comparatively small pipe between the energy storage unit and the engine compartment, limiting the airflow. Furthermore, free airflow exists within the system or engine compartment. Object and advantages of the invention

[0010] The object of the invention is, in contrast, to propose a mobile work machine with an electric drive unit comprising an electric motor and at least one electrical energy storage device for storing electrical energy for the electric motor, which significantly improves cooling.

[0011] This object is achieved, starting from a mobile work machine of the type mentioned in the introduction, by the features of claim 1. Advantageous embodiments and further developments of the invention are possible by the measures mentioned in the subclaims.

[0012] Accordingly, a work machine according to the invention is characterized in that at least one cooling hood is arranged on the electric motor, so that the cooling air flow is arranged between the cooling hood and the electric motor, wherein the cooling hood covers the electric motor and guides / directs the cooling air flow in the space between the cooling hood and the electric motor, wherein the duct section and / or the cooling air pipe forms the cooling hood.

[0013] With the help of such an air conveying device, it is possible to ensure that the electrical energy storage device, in particular, is cooled as optimally as possible. For example, an electrical and / or electronic air conveying control unit is provided, which can advantageously control or adjust the operation of the air conveying device or the cooling air flow.

[0014] The work machine according to the invention can have the electrical energy storage device for storing electrical drive energy, wherein the electrical energy is provided on the one hand to supply the drive or the drive elements such as running wheels or tracks, and on the other hand to supply further electrical and / or electronic components such as auxiliary units, lighting system, work tool and / or control of the work machine according to the invention and / or for any other purpose.

[0015] The energy storage device can comprise an electrical, rechargeable battery, such as an accumulator with electrochemical cells. For example, the use of a lithium-ion battery (Li-ion type) is possible. The selection of the electrical energy storage device or battery can be made based on energy density, i.e., the storable energy in relation to its weight. Furthermore, the heat generation during charging and discharging, which depends on the battery type, can be taken into account.

[0016] The air conveying device according to the invention can, for example, comprise a fan with a blower, which advantageously draws in air from the atmosphere or the surroundings of the work machines according to the invention by rotating a fan wheel or propeller. Furthermore, the air conveying device can also comprise an air-fillable air storage chamber or an air storage space, in particular a compressed air storage device such as a compressed gas cylinder or the like. Optionally, a pressurized nitrogen storage device or nitrogen gas cylinder can be provided, which can be used for cooling and / or, above all, for firefighting in the event of a fire, e.g., in the electrical energy storage device.

[0017] The cooling air guide device can be designed as a single piece or consist of several segments or sections, for example, arranged in parallel and / or sequentially. The cooling air guide device or individual segments thereof can be structurally integrated into other components of the work machine according to the invention, for example, into a housing or the body or the vehicle frame.

[0018] In an advantageous variant of the invention, the cooling air guide device is designed in such a way that damage or impairment caused by shocks and vibrations during operation is prevented. It is possible to design the cooling air guide device or individual segments as movable and / or expandable components, for example, with interlocking walls in the manner of a bellows or the like.

[0019] Preferably, the cooling air flow is guided along the electrical energy storage device by means of the cooling air guiding device. For example, the cooling air flow can be guided along a surface of the energy storage device. This can be achieved, for example, by allowing the cooling air flow to flow freely through a battery housing in which the energy storage device is arranged.

[0020] In general, the cooling air flow according to the invention can extract operating heat and / or intrinsic heat from the energy storage device, thereby cooling it. The operating temperature of the energy storage device can thus be reduced and maintained within the permitted operating temperature range.

[0021] In a preferred embodiment of the invention, the cooling air guiding device advantageously guides the cooling air flow to and / or along the drive. This also allows operating or inherent heat to be extracted from the drive and the drive to be cooled. The drive can advantageously be cooled by the same cooling air flow as that of the energy storage device. It is therefore possible to cool the energy storage device and the drive or electric motor with a single shared air flow.

[0022] It is thus also possible to realize cooling of at least these two components, i.e., the energy storage device and the drive motor, with only one air conveying device that generates the cooling air flow. This enables a cost-effective design of the cooling air flow guide according to the invention with low requirements for the required installation space.

[0023] For example, the energy storage device can be arranged in close proximity to the drive, so that joint cooling of at least these two components with a single cooling air flow can be achieved without great effort. For example, it is conceivable to arrange the drive motor and the energy storage device in a common housing or housing part, so that the air flow can advantageously flow within this housing / part. With such an arrangement, the inventive direction of the cooling air flow from the energy storage device to the drive can largely prevent operating heat from the drive from heating up the energy storage device.

[0024] Alternatively, or in combination with this, it is also possible to arrange the energy storage unit and the drive or drive motor at a greater spatial distance, for example, at remote positions within the vehicle frame. The cooling air flow according to the invention can then be guided, for example, through a connecting element such as a duct or a pipe / hose section from the energy storage unit to the drive motor. This allows, on the one hand, the energy storage unit to be effectively cooled with fresh or relatively cool ambient air without being additionally heated by the drive unit, and, on the other hand, sufficient cooling of the drive unit can be achieved with the same cooling air flow.

[0025] Advantageously, the cooling air guiding device is designed to guide / direct the cooling air flow from the energy storage device to the control unit and from the control unit to the electric motor and / or another electrical component, in particular a converter, inverter, auxiliary electric motor, electrically driven hydraulic pump, working electric motor of the work tool, or the like. This ensures that other components of the mobile work machine can also be advantageously cooled, in particular with the air conveying device according to the invention.

[0026] Preferably, at least one body and / or an outer shell of the work machine has at least two inlet openings of the cooling air guiding device for the inflow of cooling air for the cooling air flow. This enables, on the one hand, a defined inflow or intake and, on the other hand, an advantageous flow, in particular an increase in the inflow velocity, through a reduced or predetermined intake / inflow cross-sectional area. This improves the cooling or the removal of thermal energy from / at the energy storage device.

[0027] In an advantageous variant of the invention, the cooling air guiding device comprises at least one cooling air divider for dividing the cooling air flow into two partial air flows. This advantageously allows the cooling air flow to be divided and directed at least partially in parallel through the mobile work machine or within the body. The cooling air flow can thus be distributed among several heat-generating components that are to be cooled in parallel.

[0028] Furthermore, it is advantageously possible to provide the various heat-generating components with a stronger or weaker cooling air flow depending on the cooling requirements. For example, in a first section, the energy storage device can be cooled with the full cooling air flow, but the cooling air flow can be branched or divided in a further section so that smaller components are cooled with a smaller partial flow and / or the electric motor is cooled with a stronger / larger partial cooling air flow or, after cooling various smaller components, such as the control unit or the like, is cooled again with a combined or unified, entire cooling air flow.

[0029] The cooling air flow of the energy storage unit and at least one additional cooling air flow can also be designed separately from the outset and supplied to the respective component. For example, air for the cooling air flow and the additional cooling air flows can be drawn in via multiple inlet or intake openings and directed separately to multiple heat-generating components. This enables, for example, particularly effective cooling with fresh ambient air and the design of multiple short cooling air flows within the mobile machine.

[0030] In an advantageous embodiment, the second / further or additional cooling air flow can be generated by the air conveying device and / or by a second / further air conveying device. This allows the separate cooling air flows to be directed and controlled individually or optimally.

[0031] For example, the cooling hood is also arranged on the energy storage unit and / or the control unit, so that the cooling air flow and / or one of the two partial air flows is also arranged between the cooling hood and the energy storage unit and / or the control unit. The cooling hood can advantageously cover the respective component and guide / direct the cooling air flow in the space between the cooling hood and the respective component. In this case, the cooling hood advantageously forms, for example, the aforementioned channel. This further improves the cooling of the energy storage unit and / or the other components.

[0032] Preferably, at least one temperature sensor is provided for detecting at least one operating temperature, in particular of the energy storage device, electric motor, and / or control unit. This advantageously allows the respective operating temperature of the respective component to be determined, in particular to detect / detect an exceedance of a limit temperature or maximum permissible operating temperature.

[0033] Advantageously, at least one air conveying control unit is provided for controlling the air conveying device as a function of the operating temperature. Thus, the air conveying device and / or the further air conveying device can advantageously be controlled as a function of the operating temperature of one of the heat-generating components, i.e., the energy storage device, the drive motor, the controller, or the like. For example, an operating temperature of the respective component can be detected, and operation of the air conveying device can be initiated as a function of whether a predetermined temperature threshold is exceeded. Preferably, a control / adjustment of the speed of the air conveying device is implemented.

[0034] In a particular development of the invention, at least one thermal protection device is provided to protect the energy storage device and / or the electric motor and / or the control unit from (external) heat. This thermal protection device or insulation device can prevent or at least reduce the transfer of working heat from the electric motor and / or the control unit, etc., to the energy storage device. In conjunction with the cooling air flow, this allows for even more effective cooling of the energy storage device.

[0035] Advantageously, the thermal protection device is designed as a separating unit and arranged at least between the energy storage device and / or the electric motor and / or the control unit and / or the further electrical component. For example, the thermal protection device comprises an air-filled intermediate space between the energy storage device and the other heat-generating components, wherein the air in the intermediate space is not part of the cooling air flow according to the invention. The air-filled intermediate space can be achieved, for example, by a remote, spatially separated arrangement of the energy storage device from the other heat-generating components. Due to the remote arrangement, air can circulate between the energy storage device and the other heat-generating components and dampen heat transfer.Alternatively or in combination therewith, the thermal protection device may additionally comprise advantageous insulating materials, such as mineral or organic fibers or foams, and / or reflective surfaces, etc.

[0036] It is conceivable that the electric motor of the drive unit advantageously serves as the drive for the air conveying device. Thus, a shaft of the air conveying device and a motor shaft of the drive motor or electric motor can be formed as a single piece or in multiple parts / two parts and coupled together. For example, it is possible to arrange a propeller or fan wheel of the air conveying device on or at the motor shaft of the drive motor. A separate drive for the air conveying device is not required with such an arrangement, so that the design effort can be minimized.

[0037] In general, the following can be highlighted as essential advantages of the mobile work machine according to the invention: The cooling air flow is guided along several components and is therefore used optimally, ie multiple use of the cooling air flow, the initially particularly cold cooling air flow first cools the particularly temperature-sensitive components, ie primarily the Li-ion battery, and then the less critical components such as an inverter, the drive motor, etc., only a single fan is necessary to generate the air flow, the channeling of the air flow within the vehicle improves the cooling effect, the air cooling according to the invention is inexpensive, but still powerful, water cooling would be considerably more expensive and complex. Example

[0038] An embodiment of the invention is shown in the drawing and is explained in more detail below with reference to the single figure. Figure 1a schematic structure of a mobile work machine according to the invention.

[0039] In Figure 1 1 schematically shows a wheel loader 1 as a mobile work machine according to the invention, wherein a lifting arm with working tool or bucket is not shown in detail solely for reasons of clarity. To drive running wheels 16, the wheel loader 1 has a drive motor 3 as an electric motor 3 in an advantageous frame structure 2 of a vehicle frame. The electric motor 3 is supplied with stored electrical energy from an electrical energy storage device 6 or battery 6 in order to drive the wheel loader 1 or the running wheels 16. Optionally, an advantageous transmission gear and / or manual transmission and / or differential gear can be provided to drive several / all running wheels 16.

[0040] A fan 4 is arranged between the electric motor 3 and the electrical energy storage unit 6 or battery 6 to draw in ambient air through inlet openings 14 of a body 17, so that the battery 6 is surrounded and cooled by a beneficial cooling air flow 10. Furthermore, the fan 4 pushes the cooling air flow 12 toward the electric motor 3, so that it is cooled with slightly less cool air. On the one hand, the drive motor 3 or electric motor 3 tolerates somewhat higher operating temperatures than the battery 6, and on the other hand, due to its advantageous positioning in the vehicle frame or on the floor of the body 17, the drive motor 3 is additionally cooled to a certain extent by the ambient air flowing beneath the wheel loader 1. An air outlet 15 allows the heated air flow 12 to flow out on the underside of the body 17.

[0041] The body 17 also partially fulfills the function of a cooling air guiding device, for example a channel 9 is formed below the battery 6 and / or above (and possibly to the side) of the battery 6 in the schematically illustrated embodiment the air flow 10 can also be guided or channeled in an advantageous manner.

[0042] However, special air guiding elements can also be provided, such as a wall 7 and / or partition 8, which direct / focus the air flow 10 after or "behind" the battery 6 to the fan 4, and a hood 5 or cooling housing 5, which is arranged directly on the fan 4 and is designed to be channel-like or tubular and / or completely closed at least in a first section and then, in a certain way, covers the electric motor 3 like a hood. This hood 5 advantageously directs the cooling air flow 12 to the electric motor 3 and can achieve a certain increase in the flow velocity of the air flow 12 compared to the flow velocity of the sucked-in air flow 10. This advantageously allows sufficient heat energy to be dissipated from the electric motor 3 even when the cooling air flow 12 has already been slightly heated by the waste heat from the battery 6.

[0043] The partition wall 8 is also designed as a heat protection wall 8, which may have a reflective layer / coating in order, for example, to prevent or at least significantly reduce the radiation of waste heat from the electric motor 3 towards the battery 6.

[0044] In addition, further components or so-called auxiliary units of the wheel loader 1 can be cooled by means of the fan 4 or the cooling air streams 10, 12. For example, an electrical control unit 11 and / or an auxiliary unit 13 or an electric motor 13 designed as a hydraulic pump motor can also be cooled by the air stream(s) 10, 12. According to the invention, however, the energy storage unit 6 or battery 6 should be the first structural unit to be exposed to ambient air or cooled in order to ensure the best possible cooling of this particularly stressed and temperature-sensitive battery 6. List of reference symbols

[0045] 1 Wheel loader 2 Frame structure 3 Drive motor 4 Fan 5 Hood / Cooling housing 6 Energy storage / battery 7 Wall 8 Partition 9 Duct 10 Cooling air flow 11 Control system 12 Cooling air flow 13 Auxiliary unit / Electric motor 14 Inlet openings 15 Air outlet 16 Impeller 17 Body

Claims

1. Mobile working machine (1), in particular wheel loader (1), telescopic loader, excavator, tractor or the like, having a vehicle frame and having a drive unit for driving at least one drive running wheel or a drive chain, wherein the drive unit comprises at least one electric motor (3) and at least one electrical energy store (6) for storing electrical energy for the electric motor (3), wherein at least one control unit (11) is provided for electrically and / or electronically controlling the electric motor (3) and / or the energy store (6), wherein at least one tool holding device is provided for holding a working tool, wherein in particular the tool holding device comprises at least one carrying device pivotable about a pivot axis, for example a lifting arm and / or a telescopic boom and / or a three-point lifting device, wherein at least one air conveying device (4), in particular a fan (4) or blower, is provided for generating a cooling air flow (10, 12), and wherein at least one cooling air guiding device (5, 7, 8, 9, 14, 17) is provided for guiding / leading the cooling air flow (10, 12) from the energy store (6) at least to the electric motor (3) and / or to the control unit (11), wherein the air conveying device (4) is arranged between the energy store (6) and the electric motor (3), wherein the cooling air guiding device (5, 7, 8, 9, 14, 17) comprises at least one duct portion (5) and / or one cooling air pipe (5) for the cooling air flow (10, 12) to flow through, wherein the duct portion (5) and / or the cooling air pipe (5) have / has a duct / pipe wall transverse to the flow direction of the cooling air flow, characterized in that at least one cooling hood (5) is arranged on the electric motor (3), so that the cooling air flow (10, 12) is arranged between the cooling hood (5) and the electric motor (3), wherein the cooling hood (5) covers the electric motor (3) and guides / leads the cooling air flow (10, 12) in the intermediate space between the cooling hood (5) and the electric motor (3), wherein the duct portion (5) and / or the cooling air pipe (5) form / forms the cooling hood (5).

2. Working machine according to Claim 1, characterized in that the cooling air guiding device (5, 7, 8, 9, 14, 17) is designed for guiding / leading the cooling air flow (10, 12) from the energy store (6) to the control unit (11) and from the control unit (11) to the electric motor (3) and / or a further electrical component (13), in particular a converter, inverter, additional electric motor (13), electrically driven hydraulic pump, working electric motor of the working tool or the like.

3. Working machine according to either of the preceding claims, characterized in that at least a body (17) and / or an outer shell of the working machine (1) have / has at least two inflow openings (14) of the cooling air guiding device (5, 7, 8, 9, 14, 17) for the inflow of cooling air for the cooling air flow (10, 12).

4. Working machine according to any of the preceding claims, characterized in that the cooling air guiding device (5, 7, 8, 9, 14, 17) comprises at least one cooling air divider for dividing the cooling air flow (10, 12) into two partial air flows.

5. Working machine according to Claim 4, characterized in that at least one cooling hood (5, 17) is arranged on the energy store (6) and / or on the control unit (11), so that the cooling air flow (10, 12) and / or one of the two partial air flows is arranged between the cooling hood (5) and the energy store (6) and / or the electric motor (3) and / or the control unit (11).

6. Working machine according to any of the preceding claims, characterized in that at least one temperature sensor is provided for detecting at least one operating temperature, in particular of the energy store (6), the electric motor (3) and / or the control unit (11).

7. Working machine according to Claim 6, characterized in that at least one air conveying control unit is provided for controlling the air conveying device (4) depending on the operating temperature.

8. Working machine according to one of the preceding claims, characterized in that at least one heat protection device (8) is provided for protecting the energy store (6) and / or the electric motor (3) and / or the control unit (11) from heat.

9. Working machine according to Claim 8, characterized in that the heat protection device (8) is designed as a separating unit (8) and is arranged at least between the energy store (6) and / or the electric motor (3) and / or the control unit (11) and / or the further electrical component (13).

10. Working machine according to any of the preceding claims, characterized in that the electric motor (3) of the drive unit is designed as a drive of the air conveying device (4).