Construction machine

Abstract

The invention relates to a construction machine (1000) comprising: a battery (1); at least one electric drive (2) which is supplied by the battery (1); a hydraulic circuit (3) in which hydraulic oil (4) circulates; at least one hydraulic drive (5) which is supplied by the hydraulic circuit (3); and a first coolant circuit (6) for cooling the battery (1) and the hydraulic oil (4), wherein a portion of the hydraulic oil (4) circulates in the first coolant circuit (6) as coolant.

Description

[0001] Construction machine

[0002] The invention is based on the object of providing a construction machine with components to be cooled, which has the most efficient cooling concept possible.

[0003] The construction machine has a rechargeable battery and at least one electric drive with at least one electric motor powered by the battery. The battery can be located, for example, in the construction machine.

[0004] The construction machine also has a hydraulic circuit in which hydraulic oil circulates.

[0005] The construction machine further comprises at least one hydraulic drive supplied from the hydraulic circuit. In this regard, reference is made, for example, to WO 2013 / 045167 A2 of the applicant, which shows such hydraulic circuits and associated hydraulic drives.

[0006] The construction machine further comprises a first cooling circuit for cooling the battery and the hydraulic oil, wherein at least a portion of the hydraulic oil circulates as a coolant in the first cooling circuit. The portion of the hydraulic oil that serves as a coolant can be obtained, for example, from a suction-return filter, as disclosed in WO 2013 / 045167 A2.

[0007] In one embodiment, the first cooling circuit comprises: a hydraulic oil pump for generating an adjustable volume flow of the portion of the hydraulic oil, a first cooler with adjustable cooling capacity through which the portion of the hydraulic oil flows, and a first heat exchanger downstream of the first cooler, which is thermally coupled to the battery and through which the portion of the hydraulic oil flows. The cooling capacity of the first cooler can be adjusted, for example, by means of a fan that generates an adjustable cooling air flow by means of a variable fan speed. The first cooler can also be designed as a heat pump, for example. The first cooler can be arranged, for example, in / on an outrigger leg of a self-propelled concrete pump.

[0008] In one embodiment, the construction machine further comprises: a battery temperature controller designed to regulate a battery temperature to a predeterminable setpoint, wherein a control variable of the battery temperature controller is a cooling capacity of the first cooler. The predeterminable setpoint of the battery temperature can, for example, be in the range of room temperature. In one embodiment, the construction machine further comprises: a hydraulic oil temperature controller designed to regulate a hydraulic oil temperature to a predeterminable setpoint, wherein a control variable of the hydraulic oil temperature controller is a volume flow of the portion of the hydraulic oil. The predeterminable setpoint of the hydraulic oil temperature can, for example, be in a range between 30° Celsius and 60° Celsius.

[0009] In one embodiment, the hydraulic oil temperature controller is parameterized more slowly than the battery temperature controller in order to avoid oscillations in the coupled control loops as far as possible.

[0010] In one embodiment, the at least one electric drive, for example in the form of an electric motor, is also cooled by means of the first cooling circuit.

[0011] In one embodiment, the construction machine has power electronics, for example in the form of a frequency converter, for controlling the at least one electric drive, wherein the power electronics is also cooled by means of the hydraulic oil.

[0012] In one embodiment, the first cooling circuit comprises: a second cooler through which the part of the hydraulic oil flows, and a second heat exchanger downstream of the second cooler, which is thermally coupled to the power electronics and through which the part of the hydraulic oil flows.

[0013] In one embodiment, the construction machine has a second cooling circuit for cooling the power electronics, wherein a further part of the hydraulic oil circulates as a coolant in the second cooling circuit.

[0014] In one embodiment, the first cooling circuit has a bypass valve that, in a bypass switching position, directs the portion of the hydraulic oil past the first heat exchanger, and in a cooling switching position, directs the portion of the hydraulic oil through the first heat exchanger. The bypass switching position can be activated, for example, by the battery temperature controller when battery cooling is not necessary. Accordingly, the cooling switching position can be activated by the battery temperature controller when battery cooling is necessary.

[0015] In one embodiment, the construction machine is a concrete pump.

[0016] The invention is described in detail below with reference to the drawings. Herein: Fig. 1 shows a highly schematic view of a construction machine with a first cooling circuit according to the invention for hydraulic and electric drives according to a first embodiment,

[0017] Fig. 2 highly schematically shows a construction machine according to a further embodiment and

[0018] Fig. 3 highly schematically shows a construction machine according to another embodiment.

[0019] Fig. 1 shows a highly schematic view of a construction machine 1000 in the form of a (mobile) concrete pump, comprising a rechargeable battery 1, an electric drive 2 powered by the battery 1, a hydraulic circuit 3 in which hydraulic oil 4 circulates, a hydraulic drive 5 powered by the hydraulic circuit 3, and a first cooling circuit 6 for cooling the battery 1 and the hydraulic oil 4, with a portion of the hydraulic oil 4 circulating as a coolant in the first cooling circuit 6. Apart from hydraulic oil 4, no other or different type of coolant is used.

[0020] The first cooling circuit 6 has a hydraulic oil pump 7 for generating an adjustable volume flow of the portion of hydraulic oil 4. The hydraulic oil pump 7 is, for example, a fixed-displacement pump driven by an electric motor 16 with an adjustable speed to generate the adjustable volume flow. The speed of the electric motor 16 is the control variable of the hydraulic oil temperature controller 11.

[0021] The first cooling circuit 6 further comprises a first cooler 8 with an associated fan 14 with adjustable cooling capacity, wherein the first cooler 8 is flowed through by a portion of the hydraulic oil 4. The cooling capacity can be adjusted, for example, by adjusting a fan speed.

[0022] The first cooling circuit 6 further comprises a first heat exchanger 9 connected downstream of the first cooler 8, which is thermally coupled to the battery 1 and through which part of the hydraulic oil 4 flows.

[0023] The construction machine 1000 has a battery temperature controller 10, which is designed to regulate a battery temperature measured by a temperature sensor 23 to a predeterminable setpoint, wherein a manipulated variable of the battery temperature controller 10 is the cooling capacity of the first cooler 8. The construction machine 1000 further has a hydraulic oil temperature controller 11, which is designed to regulate a hydraulic oil temperature measured by a temperature sensor 24 to a predeterminable setpoint, wherein a manipulated variable of the hydraulic oil temperature controller 11 is a volume flow of the portion of the hydraulic oil 4. The hydraulic oil temperature controller 11 is parameterized more slowly than the battery temperature controller 10, for example, by suitable selection of controller time constants, etc.

[0024] The electric drive 2 is also cooled by means of the first cooling circuit 6, for example by a heat exchanger (not shown) being thermally coupled to the electric drive 2, wherein this heat exchanger is also flowed through by the part of the hydraulic oil.

[0025] The construction machine further comprises power electronics 12 for controlling the electric drive 2.

[0026] The first cooling circuit 6 has a bypass valve 13 which, in a bypass switching position, directs the part of the hydraulic oil 4 past the first heat exchanger 9, and which, in a cooling switching position, directs the part of the hydraulic oil 4 through the first heat exchanger 9.

[0027] In the bypass switching position of the bypass valve 13, in the simplest case, the battery temperature controller 10 can be deactivated. In this case, the cooling capacity of the first cooler 8 can, for example, be set to a fixed value sufficient to cool the hydraulic oil. It is also conceivable that in this case, the hydraulic oil temperature controller 11 could influence the cooling capacity of the first cooler 8 as an additional control variable.

[0028] By means of the invention, it is possible to cool both the battery 1 of an electrically driven machine 2, in particular an electrified concrete pump, and the hydraulic oil 4. The cooling is designed as a common circuit, in particular to reduce the complexity of the mechanical system.

[0029] A defined hydraulic oil volume flow is pumped from the hydraulic circuit 3 or a hydraulic oil tank 15 by means of the hydraulic oil pump 7 through the first (hydraulic oil) cooler 8. The first cooler 8 cools the hydraulic oil 4 to a temperature that is sufficiently below the desired battery temperature. The cooled hydraulic oil 4 is then passed through the battery 1, cooling it. The hydraulic oil flow is then fed back into the hydraulic system, for example into the tank 15, and cools the hydraulic oil 4, since the target battery temperature is significantly lower than that of the hydraulic system. The temperature levels of battery 1 and hydraulic oil 4 are controlled, for example, via two control circuits. The cooling of the battery 1 takes place via a first control circuit. The battery temperature is measured and compared with the target temperature.If the temperature is too high or too low, the cooling performance of the first cooler 8 is adjusted accordingly, for example via the speed of the fan 14.

[0030] The cooling of the hydraulic oil 4 is achieved via a second control circuit. The temperature of the hydraulic oil 4 in the system / tank 15 is measured and compared with the target temperature. If the temperature is too high or too low, the cooling flow rate is adjusted accordingly.

[0031] Since the hydraulic oil 4 at the outlet of the battery 1 has a virtually constant temperature due to the battery control, the volume flow of this portion of the hydraulic oil regulates the amount of cooled oil flowing back into the hydraulic system. The volume flow can be adjusted, for example, using a variable-displacement pump with a constant speed or, as shown, using a fixed-displacement pump with a variable speed.

[0032] Since the control loops are linked via the flow rate, it makes sense to coordinate the control loops. One option is to make the hydraulic oil temperature control slower than the battery temperature control, for example, to avoid oscillations. Alternatively, the entire system can be equipped with a holistic control system, in which both temperatures plus the setpoints serve as input variables and the flow rate and cooling capacity serve as output variables.

[0033] Fig. 2 shows a highly schematic view of a construction machine 1000 according to a further embodiment. If required, the first cooling circuit 6 additionally has a second cooler 17 through which a portion of the hydraulic oil 4 flows. The first cooling circuit 6 further has a second heat exchanger 18 connected downstream of the second cooler 17, which is thermally coupled to the power electronics 12 and through which a portion of the hydraulic oil 4 flows in order to cool the power electronics 12. The second cooler 17 can have an adjustable cooling capacity. Furthermore, a temperature controller (not shown) can be provided, which regulates a temperature of the hydraulic oil 4 flowing out of the second cooler 17 to a setpoint.

[0034] Fig. 3 shows a highly schematic view of a construction machine 1000 according to a further embodiment. The construction machine 1000 has a second cooling circuit 19 for cooling the power electronics 12, wherein a further portion of the hydraulic oil 4 circulates as a coolant in the second cooling circuit 19. The second cooling circuit 19 has a further hydraulic oil pump 20, a third cooler 21, and a downstream second heat exchanger 22, which is thermally coupled to the power electronics 12 and through which the further portion of the hydraulic oil 4 flows. A temperature of the power electronics 12 can be regulated, for example, by means of an associated temperature controller, which uses, for example, a delivery rate of the further hydraulic oil pump 20 and / or a cooling capacity of the third cooler 21 as a manipulated variable.

[0035] The invention allows for a reduction in the number of physical components required for cooling, as there is no separate first cooling circuit for the battery. This also results in a simpler physical system design. Furthermore, no additional cooling medium is required, as only hydraulic oil is used.

Claims

Patent claims Construction machine (1000), comprising: a battery (1), at least one electric drive (2) supplied from the battery (1), a hydraulic circuit (3) in which hydraulic oil (4) circulates, at least one hydraulic drive (5) supplied from the hydraulic circuit (3), and a first cooling circuit (6) for cooling the battery (1) and the hydraulic oil (4), wherein in the first cooling circuit (6) a part of the hydraulic oil (4) circulates as a coolant. Construction machine (1000) according to claim 1, characterized in that the first cooling circuit (6) comprises: a hydraulic oil pump (7) for generating an adjustable volume flow of the part of the hydraulic oil (4), a first cooler (8) with adjustable cooling capacity, through which the part of the hydraulic oil (4) flows, and a first heat exchanger (9) connected downstream of the first cooler (8), which is thermally coupled to the battery (1) and through which the part of the hydraulic oil (4) flows.Construction machine (1000) according to one of the preceding claims, characterized in that the construction machine (1000) comprises: a battery temperature controller (10) designed to regulate a battery temperature to a predeterminable setpoint, wherein a manipulated variable of the battery temperature controller (10) is a cooling capacity of the first cooler (8). Construction machine (1000) according to one of the preceding claims, characterized in that the construction machine (1000) comprises: a hydraulic oil temperature controller (11) designed to regulate a hydraulic oil temperature to a predeterminable setpoint, wherein a manipulated variable of the hydraulic oil temperature controller (11) is a volume flow of the portion of the hydraulic oil (4). Construction machine (1000) according to claims 4 and 5, characterized in that the hydraulic oil temperature controller (11) is parameterized more slowly than the battery temperature controller (10). Construction machine (1000) according to one of the preceding claims, characterized in that the at least one electric drive (2) is cooled by means of the first cooling circuit (6). Construction machine (1000) according to one of the preceding claims, characterized in that the construction machine has power electronics (12) for controlling the at least one electric drive (2), wherein the power electronics (12) are cooled by means of the hydraulic oil (4). Construction machine (1000) according to claim 7, characterized in that the first cooling circuit (6) has: a second cooler (17) through which the part of the hydraulic oil (4) flows, and a second heat exchanger (18) downstream of the second cooler (17), which is thermally coupled to the power electronics (12) and through which the part of the hydraulic oil (4) flows.Construction machine (1000) according to claim 7, characterized in that the construction machine (1000) has a second cooling circuit (19) for cooling the power electronics (12), wherein a further portion of the hydraulic oil (4) circulates as a coolant in the second cooling circuit (19). Construction machine (1000) according to one of claims 2 to 9, characterized in that the first cooling circuit (6) has a bypass valve (13) which, in a bypass switching position, directs the portion of the hydraulic oil (4) past the first heat exchanger (9) and, in a cooling switching position, directs the portion of the hydraulic oil (4) through the first heat exchanger (9). Construction machine (1000) according to one of the preceding claims, characterized in that the construction machine (1000) is a concrete pump.

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