Working machine and temperature management system thereof

Abstract

Problem: To provide a temperature management system of a work machine, which is capable of managing heat using heat of a hydraulic fluid in a power-saving manner while preventing back pressure from increasing, and which includes the temperature management system. Solution: A temperature management system (31) of a work machine (1) comprises: a return line (12) that returns hydraulic oil to a tank (3); a back pressure check valve (14) provided in the return line (12) and providing back pressure to return oil; a shunt line (18) that shunts a portion of the return oil from the upstream side of the back pressure check valve (14) in the return line (12); a coolant line (33) that circulates a coolant used in a heating device (37) that heats the interior of the cab (25); and a heat exchanger (40) that exchanges heat between the shunt line (18) and the coolant line (33).

Description

Technical Field

[0001] The present invention relates to a temperature management system for a work machine and a work machine including the temperature management system, and the temperature management system performs thermal management using a hydraulic fluid. Background Art

[0002] Conventionally, in work machines such as backhoes, as a heating device for heating the interior of the cab, it has been known to obtain heat from hydraulic oil used to operate hydraulic actuators (such as hydraulic cylinders or hydraulic motors) without the need to separately supply energy such as electricity (see, for example, Patent Documents 1 and 2).

[0003] Prior Art Documents

[0004] Patent Documents:

[0005] Patent Document 1: JP 2021-80706A

[0006] Patent Document 2: JP 2022-96243A Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] However, in the temperature management system of the above work machine, a heating device is provided in the return pipeline of the hydraulic oil from the hydraulic actuator to the storage tank. Therefore, when the flow path resistance of the heat exchanger of the heating device is large, the back pressure is high, which may affect the operability of the work device driven by the hydraulic actuator.

[0009] In view of this, an object of the present invention is to provide a temperature management system for a work machine and a work machine including the temperature management system, which can use the heat of the hydraulic fluid to save electricity and manage heat while preventing an increase in back pressure.

[0010] Means for Solving the Problems

[0011] The invention according to claim 1 is a temperature management system for a work machine, the temperature management system including: a return pipeline for returning a hydraulic fluid to a storage tank; a back pressure check valve provided in the return pipeline to provide back pressure to the return fluid; a diversion pipeline for diverting a part of the return fluid from the upstream side of the back pressure check valve in the return pipeline; a coolant pipeline for circulating a coolant used in a heating device for heating the interior of the cab; and a heat exchanger for exchanging heat between the diversion pipeline and the coolant pipeline of the heating device.

[0012] The invention according to claim 2, wherein in the temperature management system of the work machine according to claim 1, the temperature management system of the work machine comprises: an auxiliary pipeline that connects from the storage tank to the diversion pipeline; a pump that is provided in the auxiliary pipeline; and an electric motor that is used to operate the pump.

[0013] The invention according to claim 3, wherein in the temperature management system of the work machine according to claim 1, the temperature management system of the work machine comprises: a coolant pipeline that circulates the coolant used in the battery thermal management system, and the battery thermal management system regulates the temperature of the battery; and a supply pipeline that supplies a part of the coolant in the coolant pipeline of the battery thermal management system to the coolant pipeline of the heating device, and is provided between the coolant pipeline of the battery thermal management system and the coolant pipeline of the heating device.

[0014] The invention according to claim 4, wherein in the temperature management system of the work machine according to claim 1, the temperature management system of the work machine comprises: a coolant pipeline that circulates the coolant used in the battery thermal management system to regulate the temperature of the battery; a coolant pipeline that circulates the coolant used in the power device thermal management system to regulate the temperature of the power device; and a supply pipeline that is provided between the coolant pipeline of the power device thermal management system and the coolant pipeline of the battery thermal management system, and supplies a part of the coolant in the coolant pipeline of the power device thermal management system to the coolant pipeline of the battery thermal management system.

[0015] The invention according to claim 5 is a work machine, which comprises: a cab that has a heating device; a storage tank that stores hydraulic fluid; and the temperature management system according to any one of claims 1 to 4.

[0016] Effects of the present invention

[0017] According to the invention of claim 1, the heat of the hydraulic fluid can be effectively utilized, so as to heat the interior of the cab in an energy-saving manner, and at the same time, the increase in back pressure caused by the flow path resistance of the heat exchanger is prevented.

[0018] According to the present invention of claim 2, even if the hydraulic fluid does not flow through the return pipeline, the auxiliary pipeline can also be used to transport the hydraulic fluid to the heat exchanger, so a heat source for heating the coolant can be obtained.

[0019] According to the invention of claim 3, the coolant heated by recovering the heat of the hydraulic fluid can also be used to heat the battery.

[0020] According to the present invention as claimed in claim 4, the heat of the power device thermal management system can be utilized to warm the battery, or the low-temperature coolant of the battery thermal management system can be utilized to cool the power device.

[0021] According to the invention as claimed in claim 5, the interior of the cab can be heated, and the power consumption of the temperature management system can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is an exemplary diagram illustrating an embodiment of a work machine including a temperature management system according to the present invention.

[0023] Figure 2 is an exemplary diagram illustrating the spring or autumn operation of the temperature management system.

[0024] Figure 3 is an exemplary diagram illustrating the winter operation of the temperature management system.

[0025] Figure 4 is an exemplary diagram illustrating the summer operation of the temperature management system. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will be described in detail below with reference to Figures 1 to 4 the embodiments shown.

[0027] Figure 1 The work machine 1 shown is a work machine such as a hydraulic excavator. Specifically, in the present embodiment, the work machine 1 describes an electric work machine such as an electric hydraulic excavator.

[0028] The work machine 1 includes a fluid pressure circuit 2. In the present embodiment, the fluid pressure circuit 2 is a hydraulic circuit and includes: a storage tank 3 for storing hydraulic oil as a hydraulic fluid; main pumps 4, 5 for supplying hydraulic oil; a hydraulic cylinder or a hydraulic motor that constitutes a fluid pressure actuator; and a control valve 7 for controlling the supply and discharge of hydraulic oil from the main pumps 4, 5 to the hydraulic cylinder or the hydraulic motor. The control valve 7 is configured to control the flow direction and flow rate of hydraulic oil to the hydraulic cylinder or the hydraulic motor by switching the position of a spool valve according to the operation of an operator and communicating or blocking an oil passage according to the switched position.

[0029] The main pumps 4, 5 are driven by a motor 8 to discharge the hydraulic oil sucked from the storage tank 3 as high-pressure pressurized oil into the pump pipelines 10, 11. In the present embodiment, the motor 8 is an electric motor. The pressurized oil discharged into the pump pipelines 10, 11 is then supplied to the cylinder or the motor via the control valve 7 and the like. The return fluid (i.e., return oil) from the cylinder or the motor is also discharged into the storage tank 3 via the control valve 7 and the return pipeline 12 and the like.

[0030] The return pipeline 12 is provided with a back-pressure check valve 14 that applies back pressure to the return oil. In addition, an oil cooler 15 is provided on the downstream side of the back-pressure check valve 14 in the return pipeline 12. The return oil is discharged to the storage tank 3 via the oil cooler 15.

[0031] In addition, a diversion pipeline 18 is connected to the return pipeline 12. The diversion pipeline 18 diverts a part of the return oil from the upstream side of the back-pressure check valve 14. The diversion pipeline 18 is connected to the return pipeline 12 at both ends, for example, bypassing the back-pressure check valve 14.

[0032] In addition, an auxiliary pipeline 20 is connected from the diversion pipeline 18 to the storage tank 3. The auxiliary pipeline 20 branches out from the pump pipelines 10, 11. The auxiliary pipeline 20 is provided with a pump 21 that transports hydraulic oil from the storage tank 3 to the diversion pipeline 18. The pump 21 is operated by an electric motor 22. In addition, a check valve 23 is provided between the downstream side of the pump 21 and the diversion pipeline 18 to prevent the backflow of the hydraulic oil. The diversion pipeline 18 is also provided with a temperature sensor 24 that detects the temperature of the hydraulic oil. In this embodiment, the temperature sensor 24 is provided at the connection point between the auxiliary pipeline 20 and the diversion pipeline 18, that is, the lowermost part of the auxiliary pipeline 20.

[0033] The work machine 1 also includes an air-conditioning system 26 that adjusts the temperature inside the cab (operator's cab) 25. In this embodiment, the work machine 1 also includes a battery thermal management system 28 that adjusts the temperature of the battery 27 that forms the power supply of the work machine 1. The work machine 1 also includes an electric device thermal management system 30 that adjusts the temperature of electric devices 29 such as motors or inverters powered by the battery 27. These air-conditioning system 26, battery thermal management system 28, and electric thermal management system 30 constitute a temperature management system 31.

[0034] The air-conditioning system 26 is also referred to as HVAC (heating, ventilation, and air conditioning). The air-conditioning system 26 has an annular coolant pipeline 33 in which coolant circulates for temperature adjustment. The coolant pipeline 33 is provided with a coolant pump 34 that transports the coolant to the coolant pipeline 33. In this embodiment, the coolant pump 34 is an electric pump driven by an electric motor.

[0035] In addition, the coolant pipeline 33 is provided with a heater core 35 that is configured to include fins in the pipeline through which the coolant transported by the coolant pump 34 flows. Opposite to the heater core 35, a fan 36 is provided to transport the air-conditioning air into the space of the cab 25. In this embodiment, the fan 36 is an electric fan. The heater core 35 and the fan 36 constitute a heating device 37 that heats the interior of the cab 25.

[0036] In addition, a part of the coolant line 33 is disposed near a part of the shunt line 18 such that the heat exchanger 40 is constructed of a part of the coolant line 33 and a part of the shunt line 18. In this heat exchanger 40, a part of the shunt line 18 is located on the primary side (high-temperature side), and a part of the coolant line 33 is located on the secondary side (low-temperature side), and heat exchange can be performed between a part of the shunt line 18 and a part of the coolant line 33. That is, the heat exchanger 40 is a waste heat recovery member that recovers the waste heat of the hydraulic oil into the air-conditioning system 26.

[0037] In addition, the coolant line 33 is provided with a heater 41 that can heat the coolant circulating in the coolant line 33. In the present embodiment, the heater 41 is an electric heater. In the illustrated example, the heater 41 is disposed on the downstream side of the heat exchanger 40 at the coolant line 33.

[0038] The coolant line 33 is also provided with a temperature sensor 42 that detects the temperature of the coolant. In the present embodiment, the temperature sensor 42 is disposed on the coolant line 33 between the coolant pump 34 and the heater core 35. That is, the temperature sensor 42 is disposed at the inlet of the coolant to the heater core 35 (heating device 37).

[0039] In addition, an evaporator 44 for cooling is disposed near the heater core 35. The evaporator 44 is disposed in a first refrigerant circulation line 45, which is a refrigerant circulation line that circulates a refrigerant to perform cooling. The first refrigerant circulation line 45 is connected to a refrigerant device 46 that has a compressor for compressing the refrigerant, a condenser for cooling the compressed refrigerant, and a receiver for removing impurities and the like from the refrigerant through the condenser. In the present embodiment, the refrigerant device 46 is controlled by a signal from a controller (not shown). In addition, in the first refrigerant circulation line 45, an expansion valve 47 is disposed on the upstream side of the evaporator 44 to adjust the pressure and flow rate of the coolant supplied to the evaporator 44. The evaporator 44, the first refrigerant circulation line 45, the refrigerant device 46, the expansion valve 47, and the fan 36 are configured to form a refrigeration device 48 for cooling the interior of the cab 25.

[0040] In addition, the temperature inside the cab 25, or the room temperature, is detected by a temperature sensor 49. Then, based on the temperature information detected by the temperature sensor 42, the set temperature information of the interior of the cab 25 set by an operator or the like, the external air temperature information (not shown), the temperature information detected by the temperature sensor 49, etc., a controller (not shown) is configured to output a signal to control at least any one of the coolant pump 34, the fan 36, and the heater 41.

[0041] The battery thermal management system 28 also uses a part of the coolant to control the temperature of the coolant, so that the battery 27 remains at an optimal temperature.

[0042] The battery thermal management system 28 has a coolant pipeline 51 for circulating the coolant. The coolant pipeline 51 is provided with a coolant pump 53, which transports the coolant to the coolant pipeline 51. In this embodiment, the coolant pump 53 is an electric pump driven by an electric motor. In addition, a part of the coolant pipeline 51 is a heat exchange pipeline 54, and the coolant transported from the coolant pump 53 disposed near the battery 27 for heat exchange flows through this heat exchange pipeline. The battery unit 55 is constructed by the heat exchange pipeline 54 and the battery 27.

[0043] The coolant flowing through the coolant pipeline 51 is cooled by a cooling device composed of an expansion valve 75 and a cooler 56. In this embodiment, a part of the refrigerant transported from the refrigerant device 46 is used to cool the cooler 56 via the expansion valve 75. The cooler 56 is configured to have a second refrigerant circulation pipeline 57, which is a refrigerant circulation pipeline connected to the refrigerant device 46 in parallel with the first refrigerant circulation pipeline 45 and is disposed near a part of the coolant pipeline 51.

[0044] Then, the coolant pipeline 51 is connected to the coolant pipeline 33 via supply pipelines 58 and 59. The supply pipeline 58 branches out between the battery unit 55 and the cooler 56 of the coolant pipeline 51 and is connected between the heater core 35 (heating device 37) of the coolant pipeline 33 and the heat exchanger 40. The supply pipeline 59 also branches out between the cooler 56 and the coolant pump 53 of the coolant pipeline 51 and is connected between the heater 41 of the coolant pipeline 33 and the coolant pump 34. Therefore, the battery thermal management system 28 is configured to have a circuit for transporting the coolant from the coolant pipeline 51 to the heat exchanger 40 of the air conditioning system 26, a circuit for directly returning the coolant to the coolant pump 53 via the cooler 56, and a circuit for returning the coolant heated by the heat exchanger 40 of the air conditioning system 26 or the heat exchanger 40 and the heater 41 to the coolant pump 53 of the coolant pipeline 51.

[0045] The flow rate of the coolant from the coolant pipeline 51 to the heat exchanger 40 is controlled by a flow control valve 60. The flow control valve 60 is, for example, a three-way valve, which controls the flow rate of the coolant circulating in the coolant pipeline 51 and the flow rate of the coolant transported from the coolant pipeline 51 to the coolant pipeline 33 (heat exchanger 40). In this embodiment, the flow control valve 60 is, for example, an electric three-way valve.

[0046] In addition, a temperature sensor 61 for detecting the temperature of the coolant is provided in the coolant line 51. In the present embodiment, the temperature sensor 61 is provided between the coolant pump 53 and the heat exchange line 54, that is, at the refrigerant inlet to the battery unit 55. For example, the temperature sensor 61 can indirectly detect the temperature of the battery 27 via the temperature of the coolant.

[0047] Then, based on the temperature information detected by the temperature sensor 61 and the like, a controller (not shown) in at least either the coolant pump 53 or the flow control valve 60 is configured to output a signal to control these components. That is, since the opening degree of the flow control valve 60 is controlled by the controller according to the temperature information detected by the temperature sensor 61, the flow rate of the coolant (which is transported from the coolant line 51 to the coolant line 33 via the supply line 58 and heated by the heat exchanger 40 or the heat exchanger 40 and the heater 41 in the coolant line 33 and then returns to the coolant line 51 via the supply line 59) is controlled according to the opening degree of the flow control valve 60, and thus the temperature of the coolant circulating in the coolant line 51 of the battery thermal management system 28 is controlled.

[0048] The power device thermal management system 30 also uses a part of the coolant to control the temperature of the coolant so that the power device 29 is maintained at an optimal temperature.

[0049] The power thermal management system 30 has a coolant line 63 for circulating the coolant. The coolant line 63 is provided with a coolant pump 65 that transports the coolant to the coolant line 63. In the present embodiment, the coolant pump 65 is an electric pump driven by an electric motor. In addition, a part of the coolant line 63 is a heat exchange line through which the coolant is transported from the coolant pump 65 provided near the power device 29 for heat exchange.

[0050] The coolant flowing through the coolant line 63 is cooled by a radiator 66 as a cooling device. The radiator 66 includes a radiator core 67 provided in the coolant line 63, a fan 68 that transports cooling air to the radiator core 67 to cool the coolant, and a coolant storage tank 69 that is a storage tank for storing the coolant and also serves as an escape path for the coolant expanding at the coolant line 63. In the present embodiment, the fan is an electric fan driven by an electric motor.

[0051] Then, the coolant line 63 is connected to the coolant line 51 via supply lines 70 and 71. The supply line 70 branches out between the power unit 29 and the radiator 66 of the coolant line 63, and is connected between the battery unit 55 and the flow control valve 60 (cooler 56) of the coolant line 51. A check valve 72 is provided in the supply line 70, which prevents the coolant from flowing back from the coolant line 51 to the coolant line 63. The supply line 71 also branches out between the radiator 66 and the coolant pump 65 of the coolant line 63, and is connected between the cooler 56 and the coolant pump 53 of the coolant line 51. Accordingly, the power unit thermal management system 30 is configured to have a circuit for delivering the coolant from the coolant line 63 to the cooler 56 of the battery thermal management system 28, a circuit for directly returning the coolant to the coolant pump 65 via the radiator 66, and a circuit for returning the coolant cooled by the cooler 56 of the battery thermal management system 28 to the coolant pump 65 of the coolant line 63.

[0052] The flow rate of the coolant delivered from the coolant line 63 to the cooler 56 is controlled by a flow control valve 73. The flow control valve 73 is, for example, a three-way valve, and controls the flow rate of the coolant circulating in the coolant line 63 and the flow rate of the coolant delivered from the coolant line 63 to the coolant line 51 (cooler 56). Accordingly, the flow control valves 73 and 60 enable the power unit thermal management system 30, the battery thermal management system 28, and the air conditioning system 26 to deliver coolant to each other. In the present embodiment, the flow control valve 73 is, for example, an electric three-way valve.

[0053] In addition, a temperature sensor 74 for detecting the temperature of the coolant is provided in the coolant line 63. In the present embodiment, the temperature sensor 74 is provided between the coolant pump 65 and the heat exchange line, that is, at the refrigerant inlet to the power unit 29. For example, the temperature sensor 74 can indirectly detect the temperature of the power unit 29 via the temperature of the coolant.

[0054] Then, based on the temperature information detected by the temperature sensor 74 or the like, a controller (not shown in at least any one of the following components) is configured to output signals to control these components: the coolant pump 65, the flow control valve 73, and the fan 68 of the radiator 66. That is, the opening degree of the flow control valve 73 is controlled by the controller according to the temperature information detected by the temperature sensor 74, so as to control the flow rate of the coolant, which is transported from the coolant pipeline 63 to the coolant pipeline 51 via the supply pipeline 70, heated by the waste heat of the battery 27, or cooled by the cooler 56 at the battery unit 55 and then returned to the coolant pipeline 63 via the supply pipeline 71. In addition, the opening degree of the flow control valve 60 of the battery thermal management system 28 is controlled by the controller according to the temperature information detected by the temperature sensor 74, so as to control the flow rate of the coolant, which is transported from the coolant pipeline 63 via the supply pipeline 70, passes through the coolant pipeline 51, reaches the air conditioning system 26 via the supply pipeline 58, is heated by the heat exchanger 40 or the heat exchanger 40 and the heater 41, and then returns from the coolant pipeline 51 via the supply pipeline 59 and reaches the coolant pipeline 63 via the supply pipeline 71. Accordingly, according to the opening degrees of the flow control valves 73 and 60, the temperature of the coolant circulating in the coolant pipeline 63 of the power device thermal management system 30 is controlled.

[0055] Next, the operation of the illustrated embodiment will be described.

[0056] In the temperature management system 31, for example, in spring or autumn, as Figure 2 shown, the battery thermal management system 28 and the power device thermal management system 30 respectively circulate the coolant and adjust the temperatures of the battery 27 and the power device 29. In the air conditioning system 26, as needed, the controller can output signals to the coolant pump 34, the fan 36, the heater 41, and the refrigerant device 46 to use or stop the heating device 37 or the refrigeration device 48.

[0057] In the battery thermal management system 28, if the temperature information detected by the temperature sensor 61 determines that the temperature of the battery 27 is higher than the predetermined temperature, the controller outputs a signal to the flow control valve 60 to close the flow control valve 60, outputs signals to the coolant pump 53 and the refrigerant device 46 to drive them respectively, and supplies the refrigerant to the cooler 56 via the second refrigerant circulation pipeline 57 to cool the coolant circulating in the coolant pipeline 51 through the cooler 56, so as to perform heat exchange between the heat exchange pipeline 54 and the battery 27 at the position of the heat exchange pipeline 54, so that the battery 27 maintains the optimal temperature.

[0058] In the power device thermal management system 30, if the temperature information detected by the temperature sensor 74 determines that the temperature of the power device 29 has risen above a predetermined temperature, the controller outputs a signal to the flow control valve 73 to close the flow control valve 73, and outputs signals to the coolant pump 65 and the fan 68 of the radiator 66 to drive these components and cool the coolant, which circulates in the coolant line 63 by flowing through the radiator core 67 fed by the fan 68, so as to perform heat exchange between the heat exchange line and the power device 29 at the position of the heat exchange line, so that the power device 29 maintains an appropriate temperature. That is, when the air conditioning system 26 is not utilized, the external air temperature (i.e., the ambient temperature of the radiator 66) is not high, so the cooling of the power device 29 can be fully covered by the cooling of the coolant by the radiator 66.

[0059] In addition, for example, during a period of low external temperature such as in winter, as Figure 3 shown, the temperature management system 31 mainly uses the heating device 37 of the air conditioning system 26 to warm the battery 27 as needed using the heat exchanger 40 or the heat exchanger 40 and the heater 41 of the air conditioning system 26, and the power device thermal management system 30 independently circulates the coolant to regulate the temperature of the power device 29, and uses the heat of the power device thermal management system 30 for the battery thermal management system 28 as needed.

[0060] In the air conditioning system 26, the controller outputs a signal to the coolant pump 34 to drive the coolant pump 34, and uses the heat exchanger 40 to recover the waste heat of the high-temperature hydraulic oil to increase the temperature of the coolant. In addition, for example, when the temperature of the hydraulic oil detected by the temperature sensor 24 is low, if the heating by the waste heat of the hydraulic oil is insufficient, the controller increases the temperature of the coolant by outputting a signal to the heater 41 and driving the heater 41. Then the controller drives the fan 36 by a signal to feed the air (i.e., the warmed air) heated by the coolant at the heat core 35 into the interior of the cab 25. The controller monitors the temperature in the cab 25 using the temperature information detected by the temperature sensor 49, and monitors the temperature of the coolant using the temperature information detected by the temperature sensor 42, while controlling the coolant pump 34, the heater 41 and the fan 36 to maintain the temperature in the cab 25 at a predetermined set temperature.

[0061] In addition, in the battery thermal management system 28, if the temperature information detected by the temperature sensor 61 determines that the temperature of the battery 27 is lower than the predetermined temperature, the controller outputs a signal according to the temperature information detected by the temperature sensor 61 to control the opening of the flow control valve 60, and outputs a signal to the coolant pump 53 to drive the coolant pump 53, so as to convey the coolant from the coolant pipeline 51 through the supply pipeline 58 to the coolant pipeline 33 of the air conditioning system 26, so as to recover the heat of the high-temperature hydraulic oil together with the coolant circulating in the coolant pipeline 33 by using the heat exchanger 40 or the heat exchanger 40 and the heater 41, and increase the temperature of the coolant. The coolant with increased temperature is partially supplied to the coolant pump 34 and circulates at the coolant pipeline 33, while the remaining coolant is shunted by the flow control valve 60 at the coolant pipeline 51 of the battery thermal management system 28 via the supply pipeline 59, converges with the coolant flowing back to the coolant pump 53 via the cooler 56, and is conveyed from the coolant pump 53 to the battery cell 55 at the coolant pipeline 51 to perform heat exchange with the battery 27 at the position of the heat exchange pipeline, so as to warm the battery 27.

[0062] In the heat exchanger 40, when the main pumps 4 and 5 in the fluid pressure circuit 2 are operating, such as when the operation is started, a part of the return oil from the control valve 7 to the storage tank 3 is shunted from the upstream side of the back pressure check valve 14 to the shunt pipeline 18 for use. In addition, in the heat exchanger 40, when the operation is stopped, if the main pumps 4 and 5 in the fluid pressure circuit 2 are not operating, such as when the operation is stopped, the controller outputs a signal to the electric motor 22 to drive the electric motor 22, and conveys the hydraulic oil from the storage tank 3 to the shunt pipeline 18 via the pump 21 for use. The oil flowing through the shunt pipeline 18 is discharged to the storage tank 3 via the oil cooler 15.

[0063] In the power device thermal management system 30, if the temperature information detected by the temperature sensor 74 determines that the temperature of the power device 29 is higher than the predetermined temperature, the controller outputs a signal to the flow control valve 73 to close the flow control valve 73, and outputs a signal to the coolant pump 65 and the fan 68 of the radiator 66 to drive these components, and cools the coolant circulating in the coolant pipeline 63 by flowing through the radiator core 67 fed by the fan 68, so as to perform heat exchange on the heat exchange pipeline and the power device 29 at the position of the heat exchange pipeline, so as to keep the power device 29 at an appropriate temperature. By controlling the opening degrees of the flow control valves 60 and 73, the heat of the power device 29 in the battery thermal management system 28 can also be utilized.

[0064] In addition, for example, during high-temperature periods (such as in summer), such as Figure 4As shown, the temperature management system 31 mainly uses the refrigeration device 48 of the air conditioning system 26. The battery thermal management system 28 uses a part of the refrigerant used in the refrigeration device 48 to cool the battery 27 as needed, and the electric power device thermal management system 30 cools the electric power device 29 alone or using the cooler 56 of the battery thermal management system 28.

[0065] In the air conditioning system 26, the controller outputs a signal to the coolant pump 34 to stop the coolant pump 34, and outputs signals to the fan 36 and the refrigerant device 46 to drive these components, and feeds the air (i.e., cold air) cooled by the operation of the evaporator 44 into the interior of the cab 25. The controller monitors the temperature inside the cab 25 using the temperature information detected by the temperature sensor 49, while monitoring the temperature of the coolant detected by the temperature sensor 42, and controls the fan 36 and the refrigerant device 46 to keep the temperature inside the cab 25 at a predetermined set temperature.

[0066] In addition, in the battery thermal management system 28, if the temperature information detected by the temperature sensor 61 determines that the temperature of the battery 27 is higher than the predetermined temperature, the controller outputs a signal to the flow control valve 60 to close the flow control valve 60, and outputs signals to the coolant pump 53 and the refrigerant device 46 to drive these components and use the cooler 56 to lower the temperature of the coolant. The coolant with the lowered temperature is supplied to the coolant pump 53, and is transported from the coolant pump 53 via the coolant line 51 to the battery unit 55 to exchange heat with the battery 27 at the position of the heat exchange line 54, thereby cooling the battery 27.

[0067] In the electric power device thermal management system 30, if the temperature information detected by the temperature sensor 74 determines that the temperature of the electric power device 29 is higher than the predetermined temperature, when the electric power device 29 can be cooled by the radiator 66, the electric power device operates alone, just like in spring, autumn or winter. That is, in the electric power device thermal management system 30, the controller outputs a signal to the flow control valve 73 to close the flow control valve 73, and outputs signals to the coolant pump 65 and the fan 68 of the radiator 66 to drive these components and cool the coolant circulating in the coolant line 63 by flowing through the radiator core 67 fed by the fan 68, thereby exchanging heat between the heat exchange line and the electric power device 29 at the position of the heat exchange line and cooling the electric power device 29 to maintain an appropriate temperature.

[0068] In addition, it is assumed that when the ambient temperature (such as extreme heat or operating in a high-temperature area) is higher than a predetermined temperature, the radiator 66 will not be able to sufficiently cool the power device 29. Accordingly, in the power device thermal management system 30, the controller outputs signals according to the temperature information detected by the temperature sensor 74 to control the opening degree of the flow control valve 73, and outputs a signal to the coolant pump 65 to drive the coolant pump 65, so as to convey the coolant from the coolant pipeline 63 of the power device thermal management system 30 to the coolant pipeline 51 of the battery thermal management system 28 via the supply pipeline 70, in order to use the cooler 56, where the coolant circulates in the coolant pipeline 51 to have its temperature reduced by the refrigerant. The coolant with the reduced temperature is partially supplied to the coolant pump 53 and circulates in the coolant pipeline 51, while the remaining coolant is diverted by the flow control valve 73 in the coolant pipeline 63 of the power device thermal management system 30 via the supply pipeline 71, converges with the coolant flowing back to the coolant pump 65 via the radiator 66, and is conveyed from the coolant pump 65 to the power device 29 via the coolant pipeline 63, so as to perform heat exchange with the power device 29 at the position of the heat exchange pipeline, thereby cooling the power device 29.

[0069] As described above, according to the above embodiment, by diverting a part of the return oil from the upstream side of the backpressure check valve 14 provided in the return pipeline 12 for returning the hydraulic oil to the storage tank 3 by the diversion pipeline 18, and constructing the heat exchanger 40 between the diversion pipeline 18 and the coolant pipeline 33 for circulating the coolant of the heating device 37, the heat of the hydraulic oil can be effectively used to heat the interior of the cab 25 in an energy-saving manner at the heating device 37, while preventing the increase in backpressure caused by the flow path resistance of the heat exchanger 40. Therefore, a working machine 1 can be provided, which can heat in an energy-saving manner while suppressing the operation of the fluid pressure actuator due to the increase in backpressure, that is, suppressing the influence on the operability of the working device actuated by the fluid pressure actuator.

[0070] Specifically, in the case of an electric working machine powered by the battery 27, as the frequency of using the heater 41 to heat the coolant of the heating device 37 increases, the power consumption of the battery 27 increases. Therefore, during the period when the use frequency of the heating device 37 is relatively high (especially in winter), due to the increase in the power consumption of the battery 27, the operating time of the heating device 37 is shortened. Therefore, in this embodiment, by recovering the heat of the hydraulic oil and using this heat to warm the coolant of the heating device 37, the use frequency of the heater 41 for warming the coolant can be reduced, and the operating time can be guaranteed.

[0071] By connecting the auxiliary pipeline 20 from the storage tank 3 to the shunt pipeline 18 and operating the pump 21 provided in the auxiliary pipeline 20 with an electric motor 22, even when the main pumps 4 and 5 are not operating and hydraulic oil does not flow through the return pipeline 12, for example, during operation stop, the auxiliary pipeline 20 can be used to transport hydraulic oil to the heat exchanger 40, so that a heat source for heating the coolant can be obtained.

[0072] By providing a heater 41 in the coolant pipeline 33, even in a state where the temperature of the hydraulic oil is low, the heater 41 can be used to heat the coolant. In addition, since the waste heat of the hydraulic oil is combinedly used by the heat exchanger 40, compared with the case where the coolant is heated only by the heater 41, the frequency of using the heater 41 is lower, and an increase in power consumption can be suppressed.

[0073] By providing a supply pipeline 58 between the coolant pipeline 51 for regulating the temperature of the battery 27 in the battery thermal management system 28 and the coolant pipeline 33 of the heating device 37 for supplying a part of the coolant of the coolant pipeline 51 of the battery thermal management system 28 to the coolant pipeline 33 of the heating device 37, the heat of the hydraulic oil can also be recovered, and the heated coolant can be used to heat the battery 27.

[0074] In addition, by adjusting the opening degree of the flow control valve 60, the coolant pipeline 51 of the battery thermal management system 28 can be connected to the coolant pipeline 33 of the air conditioning system 26 to share the coolant. Therefore, for example, the heat generated by the battery 27 can not only be dissipated by the cooler 56, but also be used to heat the cab 25 by opening the flow control valve 60.

[0075] In addition, by providing a supply pipeline 70 between the coolant pipeline 51 in which the coolant used in the battery thermal management system 28 circulates and the coolant pipeline 63 in which the coolant used in the power device thermal management system 30 for regulating the temperature of the power device 29 circulates, a part of the coolant of the coolant pipeline 63 of the power device thermal management system 30 is supplied to the coolant pipeline 51 of the battery thermal management system 28, so that heat can be exchanged between the power device thermal management system 30 and the battery thermal management system 28. For example, in winter, the battery 27 can be heated using the heat of the power device thermal management system 30, and in summer, the low-temperature coolant of the battery thermal management system 28 can be used to cool the power device 29.

[0076] Then, by adjusting the opening degrees of the flow control valves 73 and 60, the coolant pipeline 63 of the power device thermal management system 30 can be connected to the coolant pipeline 33 of the air conditioning system 26 to share the coolant. For example, the heat generated by the power device 29 can not only be dissipated by the radiator 66, but also be used to heat the battery 27 and heat the cab 25 by opening the flow control valve 73 or the flow control valves 73 and 60.

[0077] That is, according to this embodiment, by adjusting the opening degrees of the flow control valves 60 and 73, the coolant can be exchanged among the coolant pipeline 33, the coolant pipeline 51, and the coolant pipeline 63, enabling the waste heat of the hydraulic oil, the heating by the heater 41, the waste heat of the battery 27, and the waste heat of the power device 29 to be accommodated among the air conditioning system 26, the battery thermal management system 28, and the power device thermal management system 30. Therefore, the heating and thermal management of the battery 27 and the power device 29 can be achieved.

[0078] The power device thermal management system 30 cools the power device 29 through the radiator 66. However, even when the radiator 66 cannot fully perform or has difficulty performing cooling, such as in extreme heat or high-temperature regions, the opening degree of the flow control valve 73 is adjusted to deliver the coolant to the coolant pipeline 51 of the battery thermal management system 28, and the coolant cooled by the cooler 56 is returned to the power device thermal management system 30, enabling the power device 29 to be cooled and the work machine 1 to operate even in extreme heat or high-temperature regions.

[0079] Industrial applicability

[0080] The present invention has industrial application potential for business operators engaged in the manufacture, sales, etc. of temperature management systems and work machines including such temperature management systems.

Claims

1. A temperature management system for a work machine, characterized in that, the temperature management system comprises: a return pipeline for returning hydraulic fluid to a storage tank; a backpressure check valve provided in the return pipeline to provide backpressure to the return fluid; and a diversion pipeline for diverting a part of the return fluid from the upstream side of the backpressure check valve in the return pipeline; a coolant pipeline for circulating the coolant used in a heating device that heats the interior of the cab; a heat exchanger for exchanging heat between the diversion pipeline and the coolant pipeline of the heating device.

2. The temperature management system for a work machine according to claim 1, characterized in that, the temperature management system comprises: an auxiliary pipeline connecting from the storage tank to the diversion pipeline; a pump provided in the auxiliary pipeline; and an electric motor for operating the pump.

3. The temperature management system for a work machine according to claim 1, characterized in that, the temperature management system comprises: a coolant pipeline for circulating the coolant used in a battery thermal management system that regulates the temperature of the battery; a supply pipeline provided between the coolant pipeline of the battery thermal management system and the coolant pipeline of the heating device to supply a part of the coolant in the coolant pipeline of the battery thermal management system to the coolant pipeline of the heating device.

4. The temperature management system for a work machine according to claim 1, characterized in that, the temperature management system comprises: a coolant pipeline for circulating the coolant used in a battery thermal management system that regulates the temperature of the battery; a coolant pipeline for circulating the coolant used in an electric power thermal management system that regulates the temperature of an electric power device; a supply pipeline provided between the coolant pipeline of the electric power device management system and the coolant pipeline of the battery thermal management system to supply a part of the coolant in the coolant pipeline of the electric power device thermal management system to the coolant pipeline of the battery thermal management system.

5. A work machine, characterized in that, the work machine comprises: a cab having a heating device; a storage tank for storing hydraulic fluid; and the temperature management system according to any one of claims 1 to 4.

Images