Heating device of work machine, and control method of heating device of work machine

Abstract

To provide a heating device of a work machine that can reduce power used for heating.SOLUTION: A heating device 3 of a work machine includes a heating circuit 41, an electric component cooling circuit 42, a first valve 43, and a controller 47. The heating circuit 41 has a first flow path 54 through which water used for heating flows, an electric heater 51 that heats the water in the first flow path 54, and a first temperature sensor 56 that detects the temperature of the water in the first flow path 54. The electric component cooling circuit 42 has a second flow path 63 through which water that cools electric components 62 flows, and a second temperature sensor 66 that detects the temperature of the water in the second flow path 63. The first valve 43 is disposed between the heating circuit 41 and the electric component cooling circuit 42, and merges the electric component cooling circuit 42 with the heating circuit 41 or separates the electric component cooling circuit 42 from the heating circuit 41. The controller 47 operates the first valve 43 based on a detected value Tc of the first temperature sensor 56 and a detected value Te of the second temperature sensor 66.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a heating device for a work machine and a method for controlling a heating device for a work machine. [Background technology]

[0002] In recent years, work machines equipped with a battery-driven electric motor as a power source have come into use. In such electric work machines, hot water for air conditioning is heated by an electric heater (see, for example, Patent Document 1). In the heating device for the work machine shown in Patent Document 1, an electric heater is provided in a radiator, and water in the radiator is heated by the electric heater and supplied to a heat exchanger in a heater unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-267037 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the water cooled to the outside air temperature is heated by the electric heater, the electric heater requires a large amount of power, which shortens the operating time for the work.

[0005] An object of the present disclosure is to provide a heating device for a work machine that is capable of reducing the amount of electric power used for heating, and a method for controlling a heating device for a work machine. [Means for solving the problem]

[0006] A heating device for a work machine according to a first aspect of the present disclosure includes a heating circuit, an electric component cooling circuit, a first valve, and a controller. The heating circuit has a first flow path through which a refrigerant used for heating flows, an electric heater that heats the refrigerant in the first flow path, and a first temperature sensor that detects the temperature of the refrigerant in the first flow path. The electric component cooling circuit has a second flow path through which a refrigerant that cools an electric component flows, and a second temperature sensor that detects the temperature of the refrigerant in the second flow path. The first valve is disposed between the heating circuit and the electric component cooling circuit and merges the electric component cooling circuit into the heating circuit or separates the electric component cooling circuit from the heating circuit. The controller operates the first valve based on the detected values ​​of the first temperature sensor and the second temperature sensor.

[0007] A control method for a heating device of a work machine according to a second aspect of the present disclosure includes a first temperature acquisition step, a second temperature acquisition step, and a flow path control step. The first temperature acquisition step acquires the temperature of refrigerant in a heating circuit including a first flow path through which refrigerant used for heating flows and an electric heater that heats the refrigerant in the first flow path. The second temperature detection step acquires the temperature of refrigerant in an electric component cooling circuit including a second flow path through which refrigerant that cools electric components flows. The flow path control step merges the electric component cooling circuit into the heating circuit or separates the electric component cooling circuit from the heating circuit based on the temperatures acquired in the first temperature acquisition step and the second temperature acquisition step. [Effects of the Invention]

[0008] According to aspects of the present disclosure, it is possible to provide a heating device for a work machine that is capable of reducing the amount of electric power used for heating, and a method for controlling a heating device for a work machine. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view showing an electric shovel according to an embodiment of the present disclosure. FIG. [Figure 2] 1 is a diagram showing the internal configuration of a cab and the configuration of a heating device of an electric excavator according to an embodiment of the present disclosure. FIG. [Figure 3]FIG. 4 is a flow chart for explaining control of a heating circuit of a heating device in an electric shovel according to an embodiment of the present disclosure. [Figure 4] 4 is a flow diagram for explaining control of an electric component cooling circuit, a first valve, a hydraulic oil cooling circuit, and a heat exchange switching unit of a heating device in an electric shovel according to an embodiment of the present disclosure. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] An electric shovel as an example of a work machine according to the present disclosure will be described below with reference to the drawings.

[0011] <Configuration> (Outline of Electric Excavator 1) FIG. 1 is a side view showing the configuration of an electric shovel 1 according to this embodiment.

[0012] The electric shovel 1 (an example of a work machine) is operated by electricity. The electricity is stored in a battery 62b (see FIG. 2), which will be described later. The electric shovel 1 has a shovel main body 2 and a heating device 3 (see FIG. 2). The heating device 3 heats the inside of a cab 14 of the shovel main body 2.

[0013] The shovel body 2 has a running body 11 and a revolving body 12. The running body 11 has a pair of running devices 11a (only the left one is shown in FIG. 1). Each running device 11a has a crawler belt 11b. The electric motor is rotated by power from a battery 62b (see FIG. 2), which will be described later, to drive the crawler belt 11b, causing the electric shovel 1 to travel.

[0014] The rotating unit 12 is disposed above the running unit 11. The rotating unit 12 is configured to be able to rotate relative to the running unit 11 around an axis along the vertical direction. The rotating unit 12 has a rotating frame 13, a cab 14, and a work implement 15. The rotating frame 13 is disposed above the running unit 11 and is a frame that is able to rotate relative to the running unit 11.

[0015] The work implement 15 is attached to the front center position of the revolving frame 13. As shown in FIG. 1 , the work implement 15 has a boom 21, an arm 22, and a bucket 23. The base end of the boom 21 is rotatably connected to the revolving frame 13. The tip end of the boom 21 is rotatably connected to the base end of the arm 22. The tip end of the arm 22 is rotatably connected to the bucket 23. The bucket 23 is attached to the arm 22 so that its opening can face toward the revolving unit 12 (rearward).

[0016] Hydraulic cylinders 24 to 26 (boom cylinder 24, arm cylinder 25, and bucket cylinder 26) are arranged corresponding to the boom 21, arm 22, and bucket 23, respectively. The boom cylinders 24 are arranged on both the left and right sides of the boom 21. The work implement 15 is driven by driving these hydraulic cylinders 24 to 26 (an example of a hydraulic actuator). This allows work such as excavation to be performed.

[0017] Behind the cab 14 of the revolving body 12, electrical components 62 and a hydraulic pump 71, which will be described later, are housed.

[0018] The cab 14 is provided at the front left position of the revolving frame 13. Figure 2 is a diagram showing the configuration of the heating device 3 and the interior of the cab 14. The cab 14 has a driver's seat 27, an air conditioning duct 28, an outside air filter 29, an inside air filter 30, a fan 31, and an evaporator 32.

[0019] An operator sits in the operator's seat 27. Although not shown, operating members for operating the traveling device 11a and the work implement 15, as well as an input device for inputting operation-related information, etc. are provided inside the cab 14. An air conditioning duct 28 is provided in the cab 14. The air conditioning duct 28 supplies warm air to the operator seated in the operator's seat 27. The air conditioning duct 28 guides the air outside and inside the cab 14 to above the operator's seat 27.

[0020] The outside air filter 29 is disposed at the opening of the air conditioning duct 28 that takes in air outside the cab 14. The outside air filter 29 removes dust and other particles from the air that is taken in by the air conditioning duct 28. The inside air filter 30 is disposed at the opening of the air conditioning duct 28 that takes in air inside the cab 14. The inside air filter 30 removes dust and other particles from the air that is taken in by the air conditioning duct 28.

[0021] The fan 31 is disposed inside the air conditioning duct 28, inside the outside air filter 29. The fan 31 draws air into the air conditioning duct 28 through the outside air filter 29 and the inside air filter 30. The evaporator 32 is disposed in the air conditioning duct 28. The evaporator 32 reduces humidity by cooling the air drawn in through the outside air filter 29 and the inside air filter 30.

[0022] (Heating device 3) The heating device 3 heats the cab 14. The heating device 3 has a heating circuit 41, an electric component cooling circuit 42, a first valve 43, a hydraulic oil cooling circuit 44, a heat exchange switching unit 45, a heating switch 46, and a controller 47.

[0023] The heating circuit 41 heats the interior of the cab 14. The electric component cooling circuit 42 cools the electric components 62. The first valve 43 joins the electric component cooling circuit 42 to the heating circuit 41 or separates the electric component cooling circuit 42 from the heating circuit 41. The hydraulic oil cooling circuit 44 cools the hydraulic oil. The heat exchange switching unit 45 switches between a state where heat exchange is possible between the hydraulic oil cooling circuit 44 and the electric component cooling circuit 42 and a state where heat exchange is stopped between the hydraulic oil cooling circuit 44 and the electric component cooling circuit 42. The controller 47 controls the heating device 3.

[0024] (Heating circuit 41) The heating circuit 41 includes an electric heater 51, a first water tank 52, a heater core 53, a first flow path 54, a first water pump 55, and a first temperature sensor 56.

[0025] The electric heater 51 heats water (refrigerant) used for heating. The electric heater 51 is, for example, an electric heater.

[0026] The electric heater 51 is disposed in the first water tank 52. The electric heater 51 heats the water in the first water tank 52. The electric heater 51 is controlled to turn on and off by an on signal and an off signal from the controller 47.

[0027] The heater core 53 is disposed inside the cab 14 as shown in FIG. 2. The heater core 53 is provided with a flow path through which water for heating flows. The heater core 53 heats the air that is drawn in by the fan 31 through the outside air filter 29 and the inside air filter 30 and that has passed through the evaporator 32 by exchanging heat with the water. An air mix damper 57 is disposed in the heater core 53, which can adjust the amount of air passing through the heater core 53.

[0028] The first flow path 54 is a flow path through which water heated by the electric heater 51 passes. The first flow path 54 connects the first water tank 52 and the heater core 53, and circulates the water.

[0029] The first water pump 55 is disposed in the first flow path 54. The first water pump 55 is disposed between the heater core 53 and the first water tank 52. The first water pump 55 circulates water between the first water tank 52 and the heater core 53. When the water flow caused by the first water pump 55 is taken as a reference, the first water pump 55 is disposed in a portion of the first flow path 54 downstream of the first water tank 52 and upstream of the heater core 53.

[0030] The first temperature sensor 56 detects the temperature Tc of the water in the first flow path 54. The first temperature sensor 56 detects the temperature of the water in a portion of the first flow path 54 that is downstream of the first water pump 55 and upstream of the heater core 53. The first temperature sensor 56 detects the temperature of the water that has been heated by the electric heater 51 and before it enters the heater core 53. The first temperature sensor 56 transmits information about the detected water temperature Tc to the controller 47.

[0031] (Electrical component cooling circuit 42) The electrical component cooling circuit 42 includes a radiator 61, an electrical component 62, a second flow path 63, a second water tank 64, a second water pump 65, and a second temperature sensor 66. In the electrical component cooling circuit 42, water is used as an example of a refrigerant.

[0032] The radiator 61 cools the water that cools the electric components 62. The radiator 61 cools the cooling water by, for example, exchanging heat between the outside air and the cooling water.

[0033] The electrical components 62 include a main motor 62a (electric motor), a battery 62b (electric storage device), a DC-DC converter 62c, and an inverter 62d. The main motor 62a drives a hydraulic pump 71, which will be described later. The battery 62b stores power to drive the main motor 62a. The DC-DC converter 62c boosts the voltage supplied from the battery 62b to the main motor 62a. The inverter 62d controls the main motor 62a.

[0034] The second flow path 63 is a flow path through which water that cools the electrical components 62 passes. The second flow path 63 is connected to a second water tank 64. With reference to the direction in which water flows through the second flow path 63 when driven by the second water pump 65, the second water tank 64 is disposed upstream of the electrical components 62 and downstream of the radiator 61. Water is stored in the second water tank 64. The second flow path 63 circulates water such that water discharged from the second water tank 64 passes around the electrical components 62 and the radiator 61 and returns to the second water tank 64. Note that the second flow path 63 may be configured to branch off upstream of the electrical components 62 and merge downstream of the electrical components 62 so as to pass around the main motor 62a, the battery 62b, the DC-DC converter 62c, and the inverter 62d.

[0035] The second water pump 65 is disposed in the second flow path 63. The second water pump 65 circulates water by supplying water from the second water tank 64 to the second flow path 63 and returning the water to the second water tank 64. The second water pump 65 is disposed in a portion of the second flow path 63 downstream of the second water tank 64 and upstream of the electrical component 62.

[0036] The second temperature sensor 66 detects the temperature Te of the water in the second flow path 63. For example, the second temperature sensor 66 detects the temperature of the water in a portion of the second flow path 63 downstream of the electrical component 62 and upstream of the radiator 61. The second temperature sensor 66 detects the temperature of the water that has passed around the electrical component 62. The second temperature sensor 66 transmits information about the detected water temperature Te to the controller 47.

[0037] (First valve 43) The first valve 43 is disposed between the heating circuit 41 and the electrical component cooling circuit 42. The first valve 43 is, for example, an electromagnetic valve, and is configured to merge the electrical component cooling circuit 42 into the heating circuit 41 or separate the electrical component cooling circuit 42 from the heating circuit 41 in response to a command signal from the controller 47.

[0038] In the heating circuit 41, the first valve 43 is disposed in a portion of the first flow path 54 upstream of the first water tank 52 and downstream of the heater core 53. In the electric component cooling circuit 42, the first valve 43 is disposed in a portion of the second flow path 63 upstream of the radiator 61 and downstream of the second temperature sensor 66.

[0039] The first valve 43 has four ports P1 to P4. The first valve 43 has a valve element (not shown). The valve element can be in either a confluence position T1 or a non-confluence position T2.

[0040] The first port P1 and the second port P2 are connected to the first flow path 54. The first port P1 is connected to an end of the first flow path 54 downstream of the heater core 53. The second port P2 is connected to an end of the first flow path 54 upstream of the first water tank 52.

[0041] The third port P3 and the fourth port P4 are connected to the second flow path 63. The third port P3 is connected to an end of the second flow path 63 downstream of the second temperature sensor 66. The fourth port P4 is connected to an end of the second flow path 63 upstream of the radiator 61.

[0042] When the valve element of the first valve 43 is moved to the non-merging position T2, the first port P1 connects to the second port P2, and the third port P3 connects to the fourth port P4, so that the heating circuit 41 and the electrical component cooling circuit 42 are separated and do not merge.

[0043] When the valve element of the first valve 43 is moved to the confluence position T1, it connects the first port P1 to the fourth port P4 and the second port P2 to the third port P3. This connects the heating circuit 41 with the electrical component cooling circuit 42. Specifically, the first flow path 54 and the second flow path 63 are connected in series. Specifically, water discharged from the first water tank 52, in which the electric heater 51 is installed, flows through the first water pump 55, the first temperature sensor 56, the heater core 53, port P1, port P4, the radiator 61, the second water tank 64, the second water pump 65, the electrical component 62, the second temperature sensor 66, port P3, and port P2, in this order, before returning to the first water tank 52. When the heating circuit 41 and the electrical component cooling circuit 42 are confluent, water circulates through the first flow path 54 and the second flow path 63 in this order.

[0044] (Hydraulic oil cooling circuit 44) The hydraulic oil cooling circuit 44 includes a hydraulic pump 71 , an oil cooler 72 , a third flow path 73 , a hydraulic oil tank 74 , and a third temperature sensor 75 .

[0045] The hydraulic pump 71 supplies hydraulic oil to the hydraulic cylinders 24 to 26 described above. The hydraulic oil tank 74 stores the hydraulic oil. The hydraulic pump 71 supplies the hydraulic oil from the hydraulic oil tank 74 to the hydraulic cylinders 24 to 26. The oil cooler 72 cools the hydraulic oil. The oil cooler 72 cools the hydraulic oil by, for example, exchanging heat between the outside air and the hydraulic oil.

[0046] The third flow path 73 connects the hydraulic pump 71, the hydraulic cylinders 24-26, the oil cooler 72, and the hydraulic oil tank 74. With reference to the direction in which the hydraulic oil flows due to the hydraulic pump 71, the hydraulic oil tank 74 is disposed downstream of the oil cooler 72 and upstream of the hydraulic pump 71. When the hydraulic pump 71 is driven, the hydraulic oil supplied from the hydraulic oil tank 74 to the third flow path 73 passes through the hydraulic cylinders 24-26, is cooled by the oil cooler 72, and then is returned to the hydraulic oil tank 74.

[0047] The third temperature sensor 75 detects the temperature Ts of the hydraulic oil in the third flow path 73. For example, the third temperature sensor 75 detects the temperature of the hydraulic oil in a portion of the third flow path 73 that is downstream of the hydraulic cylinders 24-26 and upstream of the oil cooler 72. The third temperature sensor 75 detects the temperature of the hydraulic oil that has been discharged from the hydraulic cylinders 24-26 and before it is supplied to the heat exchanger 83, which will be described later. The third temperature sensor 75 transmits information about the detected hydraulic oil temperature Ts to the controller 47.

[0048] (Heat exchange switching unit 45) The heat exchange switching unit 45 has a heat exchange passage 81, a bypass passage 82, a heat exchanger 83, and a second valve 84.

[0049] The heat exchange flow path 81 is a flow path that branches off from the second flow path 63, passes through the heat exchanger 83, and merges with the second flow path 63. The heat exchange flow path 81 is arranged in parallel with a flow path portion of the second flow path 63 that flows around the electrical component 62. The heat exchange flow path 81 branches off from a portion of the second flow path 63 that is upstream of the electrical component 62 and downstream of the second water pump 65, and merges with a portion of the second flow path 63 that is downstream of the electrical component 62 and upstream of the second temperature sensor 66.

[0050] The bypass flow path 82 branches off from the second flow path 63 and joins the second flow path 63 without passing through the heat exchanger 83. The bypass flow path 82 is arranged in parallel with the flow path portion of the second flow path 63 that flows around the electrical component 62 and the heat exchange flow path 81. The bypass flow path 82 branches off from a portion of the second flow path 63 that is upstream of the electrical component 62 and downstream of the second water tank 64, and joins a portion of the second flow path 63 that is downstream of the electrical component 62 and upstream of the second temperature sensor 66.

[0051] The heat exchanger 83 is disposed between the third flow path 73 and the heat exchange flow path 81. The heat exchanger 83 exchanges heat between the hydraulic oil flowing through the third flow path 73 and the water flowing through the heat exchange flow path 81. The heat exchanger 83 is disposed upstream of the oil cooler 72 and downstream of the third temperature sensor 75 in the hydraulic oil cooling circuit 44.

[0052] The second valve 84 is, for example, an electromagnetic valve. The second valve 84 is disposed between the heat exchange passage 81 and the bypass passage 82. In response to a command signal from the controller 48, the second valve 84 switches between a state in which the heat exchange passage 81 is open and the bypass passage 82 is blocked, and a state in which the heat exchange passage 81 is blocked and the bypass passage 82 is open.

[0053] The second valve 84 has four ports Q1 to Q4. The first port Q1 is connected to an upstream portion of the heat exchange passage 81. The second port Q2 is connected to an upstream portion of the bypass passage 82. The third port Q3 is connected to a downstream portion of the heat exchange passage 81. The fourth port Q4 is connected to a downstream portion of the bypass passage 82.

[0054] The second valve 84 has a valve element (not shown). The valve element can be positioned in either a heat exchange operating position R1 or a heat exchange stop position R2. When the valve element of the second valve 84 is moved to the heat exchange operating position R1, the first port Q1 and the third port Q3 are connected, and the second port Q2 and the fourth port Q4 are blocked. This opens the heat exchange passage 81 and blocks the bypass passage 82, allowing water to flow through the heat exchange passage 81 but not through the bypass passage 82. This allows heat exchange between the water flowing through the heat exchange passage 81 and the second passage 63 and the hydraulic oil flowing through the third passage 73.

[0055] When the valve element of the second valve 84 moves to the heat exchange stop position R2, the first port Q1 and the third port Q3 are blocked from communication with each other, and the second port Q2 and the fourth port Q4 are connected from each other. This blocks the heat exchange passage 81 and opens the bypass passage 82, allowing water to flow through the bypass passage 82 but not through the heat exchange passage 81. This stops heat exchange between the water flowing through the second passage 63 and the hydraulic oil flowing through the third passage 73.

[0056] (Heating switch 46) The heating switch 46 is disposed in the cab 14. The heating switch 46 is operated by the operator. When the operator turns the heating switch 46 on, the heating switch 46 sends a heating on signal to the controller 47. When the operator turns the heating switch 46 off, the heating switch 46 sends a heating off signal to the controller 47.

[0057] (Controller 47) The controller 47 includes a processor such as a CPU. The processor receives information on the water temperature Tc transmitted from the first temperature sensor 56, information on the water temperature Te transmitted from the second temperature sensor 66, and information on the hydraulic oil temperature Ts transmitted from the third temperature sensor 75. The processor performs processing for controlling the electric heater 51, the first water pump 55, the first valve 43, the second water pump 65, the second valve 84, and the hydraulic pump 71.

[0058] The controller 47 includes a storage device. The storage device includes a memory such as a RAM or a ROM, and an auxiliary storage device such as a hard disk drive (HDD) or a solid state drive (SSD). The storage device stores programs for controlling the electric heater 51, the first water pump 55, the first valve 43, the second water pump 65, the second valve 84, and the hydraulic pump 71, the allowable temperature for the temperature Te, a reference temperature for controlling the electric heater 51, and the like.

[0059] When the controller 47 receives a heating-on signal from the heating switch 46, it drives the first water pump 55 to circulate the water in the first water tank 52. When the controller 47 receives the heating-on signal, it controls the electric heater 51 on and off by sending an on or off signal to the electric heater 51 so that the water temperature Tc becomes a reference temperature. When the controller 47 receives a heating-off signal from the heating switch 46, it stops driving the first water pump 55 and turns off the electric heater 51. The reference temperature can be set to, for example, 60 degrees.

[0060] When the operator turns on the key of the electric shovel 1 and a key-on operation signal is received, the controller 47 drives the second water pump 65 to circulate the water in the second water tank 64. Furthermore, when the key-on operation signal is received, the controller 47 drives the hydraulic pump 71 to supply hydraulic oil in the hydraulic oil tank 74 to the hydraulic cylinders 24 to 26.

[0061] The controller 47 compares the water temperature Tc with the water temperature Te, and if the temperature Tc is lower than the temperature Te, sends a drive command to the first valve 43 to move the valve element of the first valve 43 to the merging position T1, or if the temperature Tc is equal to or higher than the temperature Te, to move the valve element of the first valve 43 to the non-merging position T2. ​​In this way, if the temperature Te of the water that has cooled the electrical components 62 is higher than the temperature Tc of the water flowing through the heater core 53, the temperature of the water flowing through the heater core 53 can be increased more quickly by merging the heating circuit 41 and the electrical component cooling circuit 42.

[0062] The controller 47 compares the water temperature Te with the hydraulic oil temperature Ts, and if the temperature Te is lower than the temperature Ts, moves the valve element of the second valve 84 to the heat exchange active position R1. If the temperature Te is equal to or higher than the temperature Ts, moves the valve element of the second valve 84 to the heat exchange stop position R2. In this way, when the hydraulic oil temperature Ts is higher than the temperature Te at which the electric components 62 are cooled, the water in the electric component cooling circuit 42 is caused to flow through the heat exchange flow path 81, whereby heat is transferred from the hydraulic oil to the water via the heat exchanger 83, thereby quickly increasing the temperature of the water flowing through the second flow path 63. When the heating circuit 41 and the electric component cooling circuit 42 merge, the temperature of the water flowing through the heater core 53 can be quickly increased. When the heating circuit 41 and the electric component cooling circuit 42 do not merge, the temperature of the water in the second flow path 63 can be quickly increased, because the temperature of the water can be quickly increased. This allows the heating circuit 41 and the electric component cooling circuit 42 to merge quickly, resulting in a quick increase in the temperature of the water flowing through the heater core 53.

[0063] When the water temperature Te reaches or exceeds the allowable temperature, the controller 47 moves the valve element of the second valve 84 to the heat exchange stop position R2. The allowable temperature (an example of a predetermined temperature) can be set to a temperature that is allowable for the electrical components 62. The allowable temperature can be set to 65 degrees, for example. In this way, when heat is being transferred from the hydraulic oil in the hydraulic oil cooling circuit 44 to the water in the electrical component cooling circuit 42, the heat transfer can be stopped when the temperature Te reaches the allowable temperature, thereby protecting the electrical components 62.

[0064] (Method for controlling heating device 3 of electric shovel 1) Next, a method for controlling the heating device 3 of the electric excavator 1 of this embodiment will be described. FIG.

[0065] When the operator turns on the heating switch 46 in the cab 14, the controller 47 receives a heating-on signal in step S10.

[0066] When the heating-on signal is received, the controller 47 outputs a drive command signal to the first water pump 55 to drive the first water pump 55 in step S11.

[0067] Next, in step S12, the controller 47 starts on / off control of the electric heater 51. The controller 47 controls on / off of the electric heater 51 so that the temperature Tc of the water detected by the first temperature sensor 56 becomes the reference temperature.

[0068] Next, in step S13, the controller 47 determines whether or not a heating-off signal has been received in response to an operator's operation to turn off the heating switch 46. If a heating-off signal has not been received in step S13, control returns to step S12, and the controller 47 continues the on / off control of the electric heater 51. On the other hand, if a heating-off signal has been received in step S13, control proceeds to step S14.

[0069] In step S14, the controller 47 stops the on / off control of the electric heater 51 and turns the electric heater 51 off.

[0070] Next, in step S15, a stop command signal is output to the first water pump 55 to stop the first water pump 55, and the control ends.

[0071] In this way, when the heating switch 46 is turned on, the controller 47 controls the electric heater 51 to be turned on and off until the heating switch 46 is turned off.

[0072] 4 is a flow diagram showing the control operations of the electric component cooling circuit 42, the first valve 43, the hydraulic oil cooling circuit 44, and the heat exchange switching unit 45 of the heating device 3. The control operations shown in FIG. 4 are executed in parallel with the control operations shown in FIG.

[0073] When the operator turns on the heating switch 46 in the cab 14, in the same manner as described above, the controller 47 receives a heating-on signal in step S10. Note that, because the operator has turned on the key of the electric excavator 1 before turning on the heating switch 46, the controller 47 receives the key-on operation signal, sends a drive command to the second water pump 65 to drive the second water pump 65, and sends a drive command to the hydraulic pump 71 to drive the hydraulic pump 71.

[0074] Next, in step S21 (first temperature acquisition step, second temperature acquisition step), the controller 47 receives information on the temperature Tc from the first temperature sensor 56, receives information on the temperature Te from the second temperature sensor 66, and receives information on the temperature Ts from the third temperature sensor 75.

[0075] Next, in step S22, the controller 47 compares the temperature Tc with the temperature Te. If the temperature Tc is lower than the temperature Te in step S22, the control proceeds to step S23.

[0076] In step S23 (flow path control step), the controller 47 outputs a drive command signal to the first valve 43 to move the valve element of the first valve 43 to the merging position T1. This causes the heating circuit 41 to merge with the electric component cooling circuit 42, causing the water in the electric component cooling circuit 42 to flow into the heating circuit 41, and thus the water flowing through the heater core 53 is quickly heated.

[0077] On the other hand, if temperature Tc is equal to or higher than temperature Te in step S22, control proceeds to step S24, where controller 47 outputs a drive command signal to first valve 43 to move the valve element of first valve 43 to non-junction position T2. ​​This separates heating circuit 41 and electric component cooling circuit 42, and prevents water in electric component cooling circuit 42, which has a lower temperature than the water in heating circuit 41, from flowing into heating circuit 41.

[0078] After steps S23 and S24, the control proceeds to step S25, where the controller 47 compares the temperature Te with the temperature Ts.

[0079] If it is determined in step S25 that the temperature Te is lower than the temperature Ts, the control proceeds to step S26. In step S26, the controller 47 determines whether the temperature Te is lower than the allowable temperature. If it is determined in step S26 that the temperature Te is lower than the allowable temperature, the control proceeds to step S27. In step S27, the controller 47 sends a drive command signal to the second valve 84 to move the valve element of the second valve 84 to the heat exchange operating position R1. This allows heat from the hydraulic oil in the hydraulic oil cooling circuit 44 to be transferred to the water in the electrical component cooling circuit 42.

[0080] On the other hand, if it is determined in step S25 that the temperature Te is equal to or higher than the temperature Ts, or if it is determined in step S26 that the temperature Te is equal to or higher than the allowable temperature, the control proceeds to step S28.

[0081] In step S28, the controller 47 sends a drive command signal to the second valve 84 to move the valve element of the second valve 84 to the heat exchange stop position R2. This stops the heat exchange between the hydraulic oil in the hydraulic oil cooling circuit 44 and the water in the electrical component cooling circuit 42.

[0082] After steps S27 and S28, control proceeds to step S29, where the controller 47 determines whether or not a heating-off signal has been received in response to an operator turning off the heating switch 46. If a heating-off signal has not been received in step S29, control returns to step S22, and steps S22 to S28 are repeated.

[0083] On the other hand, if a heating off signal is received in step S29, control proceeds to step S30, where the controller 47 sends a drive command signal to the first valve 43 to move the valve element of the first valve 43 to the non-junction position T2, sends a drive command signal to the second valve 84 to move the valve element of the second valve 84 to the heat exchange stop position R2, and then ends the control.

[0084] For example, when steps S23 and S27 are performed, the electric component cooling circuit 42 merges with the heating circuit 41, and heat is transferred from the hydraulic oil cooling circuit 44 to the electric component cooling circuit 42. When steps S23 and S28 are performed, the electric component cooling circuit 42 merges with the heating circuit 41, and heat transfer from the hydraulic oil cooling circuit 44 to the electric component cooling circuit 42 is stopped.

[0085] When steps S24 and S27 are performed, the electric component cooling circuit 42 does not merge with the heating circuit 41, and heat is transferred from the hydraulic oil cooling circuit 44 to the electric component cooling circuit 42. In this case, the water in the electric component cooling circuit 42 can be preheated before the electric component cooling circuit 42 merges with the heating circuit 41.

[0086] When steps S24 and S28 are executed, the electric component cooling circuit 42 does not merge with the heating circuit 41, and heat transfer from the hydraulic oil cooling circuit 44 to the electric component cooling circuit 42 is stopped.

[0087] (Features, etc.) The heating device 3 of the work machine of this embodiment is provided with a first valve 43 that is arranged between the heating circuit 41 and the electrical component cooling circuit 42 and that joins the electrical component cooling circuit 42 to the heating circuit 41 or separates the electrical component cooling circuit 42 from the heating circuit 41, and a controller 47 operates the first valve 43 based on the detection value Tc of the first temperature sensor 56 and the detection value Te of the second temperature sensor 66.

[0088] As a result, when the temperature of the water in the heating circuit 41 is lower than that of the water in the electrical component cooling circuit 42, the electrical component cooling circuit 42 is merged with the heating circuit 41, and the temperature of the water flowing in the heating circuit 41 can be quickly increased. This shortens the time that the electric heater 51 is turned on, and reduces the amount of electricity used for heating.

[0089] In addition, when the temperature of the water in the heating circuit 41 is higher than the temperature of the water in the electrical component cooling circuit 42, the electrical component cooling circuit 42 can be separated from the heating circuit 41, thereby preventing a drop in the temperature of the water in the heating circuit 41 due to the water in the electrical component cooling circuit 42 flowing into the heating circuit 41.

[0090] The heating device 3 of the work machine of this embodiment is provided with a heat exchange switching unit 45 that can switch between a state in which heat exchange is possible between the hydraulic oil cooling circuit 44 and the electrical component cooling circuit 42 and a state in which heat exchange is stopped, and the controller 47 controls the heat exchange switching unit 45 based on the detection value Te of the second temperature sensor 66 and the detection value Ts of the third temperature sensor 75.

[0091] As a result, when the temperature of the water in the electrical component cooling circuit 42 is lower than the temperature of the hydraulic oil in the hydraulic oil cooling circuit 44, the heat exchange switching unit 45 is controlled to transfer heat from the hydraulic oil in the hydraulic oil cooling circuit 44 to the water in the electrical component cooling circuit 42, thereby quickly raising the temperature of the water in the electrical component cooling circuit 42.

[0092] Furthermore, since the battery 62b provided in the electric component cooling circuit 42 can be warmed using the temperature of the hydraulic oil, it is possible to suppress deterioration of performance due to low temperatures.

[0093] In addition, when the temperature of the water in the electrical component cooling circuit 42 is higher than the temperature of the water in the hydraulic oil cooling circuit 44, the heat exchange switching unit 45 can be controlled to prevent heat from being transferred from the water in the electrical component cooling circuit 42 to the hydraulic oil in the hydraulic oil cooling circuit 44, thereby preventing a drop in the temperature of the water in the electrical component cooling circuit 42.

[0094] In the heating device 3 of the work machine of this embodiment, the controller 47 controls the heat exchange switching unit 45 to stop heat exchange when the detection value Te of the second temperature sensor 66 becomes equal to or higher than the allowable temperature. This prevents the water in the electric component cooling circuit 42 from becoming equal to or higher than the temperature that the electric components 62 can tolerate.

[0095] In the heating device 3 of the work machine of this embodiment, when the value Tc detected by the first temperature sensor 56 is equal to or greater than the value Te detected by the second temperature sensor 66 and the value Te detected by the second temperature sensor 66 is smaller than the value Ts detected by the third temperature sensor 75, the controller 47 controls the first valve 43 to separate the electric component cooling circuit 42 from the heating circuit 41 and controls the heat exchange switching unit 45 to enable heat exchange, and when the value Tc detected by the first temperature sensor 56 becomes smaller than the value Te detected by the second temperature sensor 66, the controller 47 operates the first valve 43 to merge the electric component cooling circuit 42 into the heating circuit 41. As a result, even if the temperature Tc of the water in the heating circuit 41 is lower than the temperature of the water in the electric component cooling circuit 42, the temperature of the water flowing through the second flow path 63 can be quickly raised by causing the water in the electric component cooling circuit 42 to flow through the heat exchange flow path 81 as long as the temperature Tc of the hydraulic oil is higher than the temperature Te at which the electric components 62 are cooled. Even when the heating circuit 41 and the electrical component cooling circuit 42 are not joined together, the temperature of the water in the electrical component cooling circuit 42 can be raised quickly, so the heating circuit 41 and the electrical component cooling circuit 42 can be joined together quickly, and as a result, the temperature of the water flowing to the heater core 53 can be raised quickly, and the power used by the electric heater 51 can be reduced.

[0096] (Other embodiments) Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0097] (A) In the above embodiment, an electric work machine has been described as an example of a work machine, but the work machine may also be a hybrid work machine that uses both an electric power source and an engine as its drive source.

[0098] (B) In the above embodiment, water is used as the refrigerant for the heating circuit 41 and the electrical component cooling circuit 42, but it is not limited to water.

[0099] (C) In the above embodiment, the heat exchange passage 81 and the bypass passage 82 of the heat exchange switching unit 45 are provided in the electrical component cooling circuit 42, but the heat exchange passage 81 and the bypass passage 82 may also be provided in the hydraulic oil cooling circuit 44.

[0100] (D) In the above embodiment, the hydraulic oil cooling circuit 44 is provided with the hydraulic oil tank 74 and the oil cooler 72, but the oil cooler 72 may also serve as the hydraulic oil tank 74.

[0101] (E) In the above embodiment, a shovel is used as an example of a work machine, but the present invention is not limited to a shovel and can be applied to any work machine that uses heating, such as a wheel loader or a dump truck. [Industrial Applicability]

[0102] The heating device for a work machine and the control method for a heating device for a work machine disclosed herein have the effect of making it possible to reduce the power used for heating, and are useful for electric work machines and the like. [Explanation of symbols]

[0103] 3: Heating equipment 41: Heating circuit 42: Electrical component cooling circuit 43: First valve 44: Hydraulic oil cooling circuit 47: Controller 51:Electric heater 54: First flow path 55: First water pump 56: First temperature sensor 62: Electrical parts 63: Second flow path 66: Second temperature sensor

Claims

1. a heating circuit including a first flow path through which a refrigerant used for heating flows, an electric heater that heats the refrigerant in the first flow path, and a first temperature sensor that detects the temperature of the refrigerant in the first flow path; an electrical component cooling circuit including a second flow path through which a coolant for cooling the electrical component flows, and a second temperature sensor for detecting the temperature of the coolant in the second flow path; a first valve disposed between the heating circuit and the electrical component cooling circuit, for joining the electrical component cooling circuit to the heating circuit or separating the electrical component cooling circuit from the heating circuit; a controller that operates the first valve based on the detection value of the first temperature sensor and the detection value of the second temperature sensor, Heating equipment for work machines.

2. The controller When the detected value of the first temperature sensor is equal to or greater than the detected value of the second temperature sensor, the electrical component cooling circuit is separated from the heating circuit; When the detected value of the first temperature sensor is smaller than the detected value of the second temperature sensor, the first valve is operated to merge the electrical component cooling circuit into the heating circuit. The heating device for a work machine according to claim 1.

3. a hydraulic oil cooling circuit including a hydraulic actuator, a third flow path through which hydraulic oil supplied to the hydraulic actuator flows, an oil cooler that cools the hydraulic oil flowing through the third flow path, and a third temperature sensor that detects the temperature of the hydraulic oil in the third flow path; a heat exchange switching unit that can switch between a state in which heat exchange between the hydraulic oil cooling circuit and the electrical component cooling circuit is possible and a state in which heat exchange between the hydraulic oil cooling circuit and the electrical component cooling circuit is stopped, the controller controls the heat exchange switching unit based on the detected value of the second temperature sensor and the detected value of the third temperature sensor. The heating device for a work machine according to claim 1.

4. The controller When the detected value of the second temperature sensor is equal to or greater than the detected value of the third temperature sensor, the heat exchange switching unit is controlled so that the heat exchange is stopped; When the detected value of the second temperature sensor is smaller than the detected value of the third temperature sensor, the heat exchange switching unit is controlled so as to be in a state in which the heat exchange is possible. The heating device for a work machine according to claim 3.

5. The controller When the detected value of the second temperature sensor becomes equal to or higher than a predetermined temperature, the heat exchange switching unit is controlled so that the heat exchange is stopped. The heating device for a work machine according to claim 3 or 4.

6. The controller When the detection value of the first temperature sensor is equal to or greater than the detection value of the second temperature sensor and is smaller than the detection value of the third temperature sensor, controlling the first valve to separate the electrical component cooling circuit from the heating circuit, and controlling the heat exchange switching unit to enable the heat exchange; When the detected value of the first temperature sensor becomes smaller than the detected value of the second temperature sensor, the first valve is operated to merge the electric component cooling circuit into the heating circuit. The heating device for a work machine according to claim 3.

7. The heat exchange switching unit is a heat exchanger capable of exchanging heat between the hydraulic oil cooling circuit and the electrical component cooling circuit; a heat exchange flow path connected in parallel to either the second flow path of the electrical component cooling circuit or the third flow path of the hydraulic oil cooling circuit, and in which the heat exchanger is disposed; a bypass flow path connected in parallel to the heat exchange flow path and bypassing the heat exchanger; a second valve that switches between a state in which the heat exchange passage is open and the bypass passage is closed and a state in which the heat exchange passage is closed and the bypass passage is open, the controller controls the second valve based on the detected value of the second temperature sensor and the detected value of the third temperature sensor. The heating device for a work machine according to claim 3.

8. The electrical components include an electric motor and a capacitor for driving the electric motor. The heating device for a work machine according to claim 1.

9. the electrical components include an electric motor and a capacitor for driving the electric motor; the hydraulic oil cooling circuit includes a hydraulic pump that supplies the hydraulic oil; The electric motor drives the hydraulic pump. The heating device for a work machine according to claim 3.

10. The hydraulic oil cooling circuit includes a hydraulic oil tank as the oil cooler. The heating device for a work machine according to claim 3.

11. a first temperature acquisition step of acquiring a temperature of the refrigerant in a heating circuit including a first flow path through which a refrigerant used for heating flows and an electric heater that heats the refrigerant in the first flow path; a second temperature acquisition step of acquiring a temperature of a refrigerant in an electric component cooling circuit including a second flow path through which a refrigerant for cooling the electric component flows; a flow path control step of merging the electric component cooling circuit into the heating circuit or separating the electric component cooling circuit from the heating circuit based on the temperature acquired in the first temperature acquisition step and the temperature acquired in the second temperature acquisition step. A method for controlling a heating device of a work machine.

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