CN218228611U - Cooling system for electric working machine and electric working machine comprising same - Google Patents

Abstract

The utility model relates to an electric working machine who is used for electric working machine's cooling system and includes it. The electric working machine (100) includes an electric element (51, 52, 53, 54) and a transmission (10), and the cooling system includes: a radiator (20) fluidly connected to a cooler of the electrical component in a coolant circulation loop; and an oil cooler (15) fluidly connected to the transmission (10) in an oil circulation circuit. Wherein the oil cooler (15) is also provided in the coolant circulation circuit to exchange heat between oil and coolant.

Description

Cooling system for electric working machine and electric working machine comprising same

Technical Field

The utility model relates to an electric operating machine field especially relates to a cooling system for electric operating machine.

Background

In order to follow the advanced concept of green and low carbon, achieve the goal of "double carbon", promote the transformation and upgrade of industry and the development of high quality, and the working machines (such as loaders, excavators, etc.) as important production materials are gradually developed from the traditional fuel oil type to the electric driving type.

There are a variety of electrical components associated with an electric work machine for its electric drive and control operations, including, but not limited to, various motors (e.g., a travel motor that drives the work machine forward or backward), various controllers (MCUs) (e.g., a travel motor controller), a Power Distribution Unit (PDU) that distributes and manages power from a power source, a DC/DC converter and a DC/AC inverter that convert the power, and so forth. In addition, electric working machines are often equipped with a transmission in order to better meet their traveling needs. Various electric components and a transmission of the electric working machine generate heat to cause temperature rise during operation, and excessively high temperature rise reduces the operating performance and reliability of these components, shortens their life, and further affects the overall performance and operating efficiency of the electric working machine. For this reason, a cooling system for performing thermal management is required in the electric working machine in order to prevent excessive temperatures of components such as electric elements and a transmission.

However, the existing cooling system for the electric working machine has the problems of complex structure, large occupied space, poor cooling effect and the like.

SUMMERY OF THE UTILITY MODEL

The present invention is directed to solving the above problems and/or other deficiencies in the prior art.

To this end, the present invention provides a cooling system for an electric working machine, the electric working machine including an electric element and a transmission, the cooling system including: a radiator fluidly connected to a cooler of the electrical component in a coolant circulation loop; and an oil cooler fluidly connected to the transmission in an oil circulation circuit. Wherein the oil cooler is also provided in the coolant circulation circuit to perform heat exchange between oil and coolant.

According to an exemplary configuration, the electrical components may include one or more of a travel motor, a travel motor controller, a hydraulic motor controller, a power distribution unit, a DC/DC converter, a DC/AC inverter of the electric work machine.

According to one exemplary configuration, the coolant circuit may comprise a plurality of coolant branches connected in parallel with one another, in each of which a cooler of at least one electrical component is arranged, the oil cooler being arranged in one of the coolant branches and being fluidically connected in series with the cooler of the electrical component in that coolant branch.

According to one exemplary configuration, the oil cooler can be located in the coolant branch provided in it downstream of the cooler of the at least one electrical component in the coolant branch in the flow direction of the coolant.

According to an exemplary configuration, the electric element located upstream of the oil cooler in the flow direction of the coolant in the coolant branch in which the oil cooler is provided may include a traveling motor of the electric working machine.

According to an exemplary configuration, the cooling system may further include a heat radiation fan provided for the heat radiator.

According to an exemplary configuration, the cooling system may further include one or more temperature sensors disposed at predetermined positions in the cooling system, and the radiator fan may be configured to be turned on or off or to adjust a rotational speed according to a temperature sensed by the temperature sensors.

According to an exemplary configuration, the cooling system may further include an expansion tank fluidly connected to the radiator.

The utility model also provides an electric operation machine, it includes as above cooling system.

According to one exemplary configuration, the electric work machine is an electric loader.

The utility model discloses at least one following beneficial effect has: the oil cooler for cooling the transmission is arranged in the cooling liquid circulation loop for cooling the electric element, so that the oil flowing through the transmission can be cooled by the cooling liquid, a separate heat dissipation device is not required to be arranged for the oil cooler, the structure of a cooling system is simplified, the occupied space of the cooling system is saved, and the cooling effect of the oil can be improved; by arranging the oil cooler downstream of the cooler of at least one electrical element in the flow direction of the cooling liquid, the cooling liquid heated by the heat of the electrical element can be utilized to heat the low-temperature oil during the low-temperature starting process of the working machine, so that the oil is heated more quickly, and the transmission enters a normal working state earlier, the starting process of the working machine is accelerated, and the damage of the low-temperature starting to the parts of the transmission is avoided or reduced; one or more temperature sensors are arranged in the cooling system, and the cooling fan of the radiator is regulated and controlled according to the temperature measurement result of the temperature sensors, so that the temperature in the cooling system can be controlled to be a desired value more quickly and accurately, and the heat management effect of the electric working machine is improved.

Drawings

Fig. 1 is a perspective view of an exemplary electric working machine to which a cooling system according to the present invention is applied.

Fig. 2 is a schematic diagram showing an exemplary configuration of a cooling system according to the present invention.

Detailed Description

Fig. 1 illustrates an exemplary electric work machine 100. The electric work machine 100 may be, for example, a wheel loader as shown. Electric work machine 100 may also be any other type of work machine, such as a track-type excavator, a wheel grader, etc., that performs operations associated with a particular industry (e.g., mining, construction, farming, transportation, etc.) and works and walks in a variety of work environments (e.g., mines, construction sites, farms, roads, etc.).

The electric work machine 100 may include a main frame 30, an operator accommodating space (e.g., cab 35), and a work implement 36. In one embodiment, work implement 36 may be a bucket for a loader. The electric work machine 100 may also include a hydraulic system having various hydraulic components, such as at least one hydraulic ram 37 operatively connected to the work implement 36 and configured to control the operation of the work implement 36. A traveling device 40 is disposed at a lower portion of the electric working machine 100 to support and move the electric working machine 100. In one embodiment, the running gear 40 comprises wheels 41.

The electric work machine 100 shown in fig. 1 may include various electric components related to its electric drive and control operations, including, but not limited to, various motors (e.g., a travel motor that drives the electric work machine 100 forward or backward and a hydraulic motor that drives a hydraulic pump in a hydraulic system of the electric work machine 100 to operate), various controllers (MCUs) (e.g., a travel motor controller and a hydraulic motor controller), a Power Distribution Unit (PDU) that distributes and manages power supply power, a DC/DC converter and a DC/AC inverter that convert power, and the like. The electric working machine 100 may further include a transmission to transmit the travel driving force provided by the travel motor to the traveling device 40 at an appropriate speed ratio/gear according to various operating conditions or requirements.

In order to avoid excessive temperature rise of various electric elements, transmission, hydraulic elements, and the like in the electric working machine 100 due to heat generated during operation, the electric working machine 100 is equipped with a cooling system. Fig. 2 schematically illustrates a cooling system for an electric work machine 100 according to an embodiment of the present invention.

As shown in fig. 2, the cooling system includes a coolant circulation circuit formed by fluidly connecting the radiator 20 with coolers of various electric elements 51, 52, 53, 54, wherein the coolant may be cooling water or an antifreeze. Here, the cooler of the electrical component may be a cooling device such as a heat sink, a water-cooled plate, or a thermally conductive (but electrically non-conductive) portion of the electrical component itself. The coolers for the individual electrical components are not specifically shown in fig. 2, and the coolers can be considered to be included in the respective electrical components. In this context, a component or device being "in fluid connection" with another component or device does not mean that the respective fluid must be in direct contact with the component or device, but rather that the fluid can exchange heat with the component or device directly or indirectly through intervening components (e.g., fluid conduits). Each solid line with arrows on the left side of the radiator 20 in fig. 2 shows the flow path and direction of the coolant in the coolant circulation circuit. In the illustrated embodiment, the coolant circulation loop includes three coolant branches 1,2 and 3 connected in parallel with each other. A fluid pump (e.g., an electric water pump) 61 and a cooler for the electrical components 51 are provided in the first coolant branch 1, a fluid pump 62 and a cooler for the electrical components 52 are provided in the second coolant branch 2, and a fluid pump 63 and a cooler for the electrical components 53, 54 are provided in the third coolant branch 3. When the cooling liquid circulation circuit is operated, the fluid pumps 61 to 63 are actuated, so that the cooling liquid flows out from the liquid outlet of the radiator 20 (see the small circle at the lower left corner of the radiator 20 in fig. 2), and respectively enters and flows through the cooling liquid branches 1 to 3 to cool the electric components therein, then joins the liquid inlet of the radiator 20 (see the small circle at the upper left corner of the radiator 20 in fig. 2), and dissipates the heat carried out from each cooling liquid branch in the radiator 20, and then flows out again from the liquid outlet of the radiator 20 to perform the next cooling cycle, and so on.

Advantageously, the heat sink 20 may be equipped with a heat dissipation fan 90 to improve and/or control the heat dissipation effect of the heat sink 20. In addition, the radiator 20 may also be provided with an expansion tank 25 in fluid connection therewith in order to accommodate the expansion of the coolant in the radiator 20 or to replenish the radiator 20 with coolant.

It will be understood by those skilled in the art that the number of the coolant branches is not limited to three, but may be set appropriately according to the kind, number, position, and cooling requirement (required coolant flow rate) of the electric component to be cooled, or may be one (in this case, equivalent to only the trunk line of the coolant circulation circuit), two, four, or more. The fluid pumps in each coolant branch may be identical or of different types (e.g. different head and/or flow rate); the fluid pumps in each coolant branch may be controlled independently of each other and may be selectively activated or deactivated; the arrangement of the fluid pump is not limited to providing one in each coolant branch. In addition, the type and/or number of the electric components in each coolant branch may be appropriately set in accordance with the head and/or flow rate of the corresponding fluid pump.

The cooling system according to the present invention further includes an oil cooler 15 that is fluidly connected to the transmission 10 of the electric working machine 100 in an oil circulation circuit. The oil described herein may be any suitable type of fluid, such as transmission oil. In the oil circulation circuit, oil flows through the transmission 10 to lubricate and cool the transmission, and then returns to the oil cooler 15 to dissipate heat carried back from the transmission. According to the invention, the oil cooler 15 is also arranged in the coolant circuit, for example in the coolant branch 2 as shown in fig. 2. In this way, the coolant in the coolant circulation circuit also flows through the oil cooler 15, so that heat exchange with the oil therein, in other words, the oil can be cooled or heated by the coolant. In the cooling system of the conventional electric working machine, the oil cooler is provided independently of the cooling module of the electric component, and an independent heat dissipation device (such as a heat dissipation fan) needs to be provided to dissipate heat from the oil cooler, resulting in a complicated structure, a large space size, and a high cost of the cooling system. Compared with the prior art, the oil cooler is integrated into the cooling liquid circulation loop for cooling the electric element, and the cooling liquid can be used for dissipating heat of the oil cooler, so that the oil cooler is free from being additionally provided with a heat dissipation device, and the space size and the complexity of a cooling system are further reduced; in addition, the water cooling heat radiation method according to the coolant can improve the heat radiation effect to the oil cooler, compared to the air cooling heat radiation generally adopted to the oil cooler in the prior art.

In the illustrated embodiment, the oil cooler 15 is fluidly connected in series with the cooler of the electrical component 52 in the second coolant branch 2. According to an exemplary arrangement, the oil cooler 15 is located downstream of the cooler of the electrical component 52 in the second coolant branch 2 in the direction of flow of the coolant. Thus, the coolant flows through the cooler of the electric element 52 before flowing through the oil cooler 15, that is, flows to the oil cooler 15 after absorbing heat of the electric element 52 and increasing in temperature. This is advantageous for the cold start process of the electric working machine, because the cold oil in the oil cooler 15 can be heated by the warmed coolant, so that the oil is warmed up faster and the transmission 10 is thereby put into a normal operating state earlier, and damage to transmission parts from the cold start can be avoided or reduced while the start process of the working machine is accelerated.

The specific cooling liquid branch in which the oil cooler 15 is arranged may depend on the kind and/or number of electrical components arranged in the cooling liquid branch and the flow rate and lift of the respective fluid pump. Overall, the total flow resistance (or pressure drop) and the cooling requirement (required coolant flow) of the oil cooler 15 and the electrical components in the coolant branch are matched to the head and flow of the fluid pump in the coolant branch. In addition, in the case of the same fluid pump for each coolant branch, the total flow resistance and the total flow rate of the electrical components and/or the oil cooler provided in each coolant branch are preferably also substantially the same between the coolant branches. In one embodiment, for example, electrical component 51 may be one or more Motor Controllers (MCUs), electrical component 52 may be a walking motor, electrical component 53 may be one or more of a Power Distribution Unit (PDU), a DC/DC converter, and a DC/AC inverter, and electrical component 54 may be a hydraulic motor.

The cooling system shown in fig. 2 may further include a hydraulic fluid cooler 70 fluidly connected to a hydraulic fluid tank 73 in the hydraulic system of the electric work machine in a hydraulic fluid circulation circuit to dissipate hydraulic fluid in the hydraulic fluid tank 73. The hydraulic reservoir 73 is fluidly connected to an exemplary hydraulic element 75 in the hydraulic system to drive the hydraulic element 75 into operation. The hydraulic fluid cooler 70 may also dissipate heat, for example, by means of a radiator fan 90. In the present invention, it is also conceivable to provide a hydraulic fluid cooler 70 in the coolant circulation circuit in place of the above-described oil cooler 15 for the transmission.

In the cooling system shown in fig. 2, one or more temperature sensors may be provided at predetermined positions. For example, temperature sensors 81, 82, 83, 84 may be provided at a position downstream of electrical component 51, upstream of electrical component 52, upstream of electrical component 54, and at hydraulic reservoir 73, respectively, to sense temperatures associated with these electrical components and hydraulic reservoir, respectively. These temperature sensors may be in signal communication with an electronic control unit 95, and the electronic control unit 95 is in signal communication with the heat dissipation fan 20 (see dashed lines in fig. 2). In this way, the electronic control unit 95 can receive the temperature signals sensed by the temperature sensors and control the start/stop or the rotation speed of the cooling fan 20 accordingly. That is, the heat dissipation fan 20 can be adjusted according to the temperature of a specific element or location in the cooling system to increase or decrease the heat dissipation capacity of the cooling system, so as to adjust the feedback of the temperature in the cooling system to a desired value.

Industrial applicability

The cooling system according to the present invention can be used in various electric working machines, such as an electric loader or an electric excavator.

When the cooling system is in operation, each fluid pump 61, 62, 63 in the coolant circulation circuit is actuated so that coolant flows out of the outlet port of the radiator 20 and into and through the coolant branches 1,2,3, respectively, to cool the respective electrical components 51 to 54. At the same time, the coolant flows through the oil cooler 15 in the coolant branch 2 to cool or heat the oil flowing through the transmission. Next, the cooling liquid flowing out from each of the cooling liquid branches 1,2, and 3 joins and flows into the liquid inlet of the radiator 20, and dissipates the heat brought out from each of the cooling liquid branches in the radiator 20, and then flows out from the liquid outlet of the radiator 20 again to perform the next cooling cycle.

It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments disclosed above without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples disclosed herein be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.

Claims (10)

1. A cooling system for an electric working machine, the electric working machine (100) including an electric element (51, 52, 53, 54) and a transmission (10), the cooling system characterized by comprising:

a radiator (20) fluidly connected to a cooler of the electrical component in a coolant circulation loop; and

an oil cooler (15) fluidly connected to the transmission (10) in an oil circulation circuit,

wherein the oil cooler (15) is also provided in the coolant circulation circuit to perform heat exchange between oil and coolant.

2. The cooling system according to claim 1,

the electrical components (51, 52, 53, 54) comprise one or more of a travel motor, a travel motor controller, a hydraulic motor controller, a power distribution unit, a DC/DC converter, a DC/AC inverter of the electric working machine.

3. The cooling system of claim 1,

the coolant circuit comprises a plurality of coolant branches (1, 2, 3) connected in parallel to each other, in each of which a cooler of at least one electrical component is arranged, the oil cooler (15) being arranged in one of the coolant branches and being fluidically connected in series with the cooler of the electrical component (52) in that coolant branch (2).

4. The cooling system according to claim 3,

the oil cooler (15) is located in the coolant branch (2) provided in the oil cooler downstream of the cooler of at least one electrical component in the coolant branch in the direction of flow of the coolant.

5. The cooling system according to claim 4,

an electric component located upstream of the oil cooler in a flow direction of the coolant in a coolant branch (2) in which the oil cooler (15) is provided includes a traveling motor of the electric working machine (100).

6. The cooling system according to any one of claims 1 to 5,

the cooling system further includes a heat radiation fan (90) provided for the heat radiator (20).

7. The cooling system of claim 6,

the cooling system further comprises one or more temperature sensors (81, 82, 83, 84) arranged at predetermined positions in the cooling system, the radiator fan (90) being configured to be switched on and off or to adjust the rotational speed in dependence of the temperature sensed by the temperature sensors.

8. The cooling system according to any one of claims 1 to 5,

the cooling system further comprises an expansion tank (25) in fluid connection with the radiator (20).

9. An electric working machine (100), characterized by comprising a cooling system according to any one of claims 1-8.

10. The electric work machine of claim 9,

the electric working machine (100) is an electric loader.

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