Work vehicle

Abstract

To suppress excessive temperature rise of an electronic apparatus stored in a bonnet.SOLUTION: A work vehicle includes: an electric motor (4) for driving travel devices (2, 3) of a vehicle body (1a); a first battery (123) arranged in a bonnet (6); a second battery (101) supported by the vehicle body (1a); a switching unit (124) for performing switching control of power reception and supply of the first battery (123) and power reception and supply of the second battery (101), the switching unit (124) being stored in the bonnet (6); a cooler (132) arranged in front of the switching unit (124) so as to cool the inside of the bonnet (6); and a heat exchanger (131) which is arranged in the bonnet (6) and is arranged corresponding to the cooler (132), and cools a refrigerant for cooling the electric motor (4).SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a work vehicle, and more particularly to a work vehicle in which a traveling device and a work machine are electrically driven. [Background technology]

[0002] In a plug-in hybrid vehicle that uses an electric motor as a power source, in which a traction motor (1) is disposed inside a power compartment (R) and a drive battery (2) and an auxiliary battery (4) that supply power to the traction motor (1) are disposed outside the power compartment (R), a technology is known in which an electric fan (14), a radiator (13), and a condenser (23) are disposed in that order at the front end portion of the power compartment (R) to cool the condenser (23) and the radiator (13) with the wind from the electric fan (14) and to increase or decrease the rotation speed of the electric fan when a request to drive the electric fan is made while the vehicle is not in operation (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7310565 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional technology, the electric motor is placed in the power compartment, i.e., the space inside the bonnet, while the battery is placed outside the bonnet. If the battery or electric circuit is placed inside the bonnet, it may generate heat due to changes in voltage and current during use, energy loss, etc., and the temperature control by the conventional technology for controlling the electric fan may be insufficient, leading to the risk of malfunction or thermal runaway.

[0005] The present invention has a technical object to suppress an excessive rise in temperature of electronic devices housed under a bonnet. [Means for solving the problem]

[0006] The above-mentioned problems of the present invention are solved by the following means. The invention described in claim 1 is a work vehicle comprising: a vehicle body (1a); an electric motor (4) for driving running gear (2, 3) of the vehicle body (1a); a bonnet (6) arranged in the front of the vehicle body (1a); a first battery (123) arranged inside the bonnet (6); a second battery (101) supported by the vehicle body (1a); a switching unit (124) for controlling switching between power supply to and from the first battery (123) and power supply to and from the second battery (101), the switching unit (124) being housed in the bonnet (6); a cooler (132) arranged in front of the switching unit (124) for cooling the inside of the bonnet (6); and a heat exchanger (131) arranged in the bonnet (6) and corresponding to the cooler (132) for cooling a refrigerant for cooling the electric motor (4).

[0007] The invention described in claim 2 is the work vehicle described in claim 1, characterized in that it includes a power supply case (128) that houses a power supply cord (127) that supplies power to the first battery (123), the power supply case (128) being arranged on a side of the bonnet (6).

[0008] The invention described in claim 3 includes a work machine supported on the vehicle body (1a) and performing work on a field, a work machine support part (15, 16) for detachably supporting the work machine, the work machine support part (15, 16) to which the second battery (101) can be attached in place of the work machine, a current detector (107) connected to the second battery (101) for detecting a current, and a wiring device connected to the current detector (107) for cutting off the current when an overcurrent is detected. The work vehicle according to claim 1 further comprises a circuit breaker (106), a second switching circuit (110) that controls switching between power supply and reception of the second battery (101), and a transformer (113) that transforms the power supplied to the second switching circuit (110), and the current detector (107), the wiring circuit breaker (106), the second switching circuit (110), and the transformer (113) are arranged in close proximity to each other and above the second battery (101).

[0009] The invention described in claim 4 is the work vehicle described in claim 1, characterized in that it includes a first temperature sensor (SN1) that detects the temperature inside the hood (6), and a control means (141) that switches to an energy saving mode in which the power supply rate of the first battery (123) is reduced when the temperature detected by the first temperature sensor (SN1) reaches a predetermined temperature.

[0010] The invention described in claim 5 is the work vehicle described in claim 1, characterized in that it includes a second temperature sensor (SN2) that detects the temperature of the second battery (101), and a control means (141) that switches to an energy saving mode in which the power receiving rate of the second battery (101) is reduced when the temperature detected by the second temperature sensor (SN2) reaches a predetermined temperature.

[0011] The invention described in claim 6 is the work vehicle described in claim 4 or 5, characterized in that it comprises a second work implement (18) supported by the vehicle body (1a) and performing work on a field, a second electric motor (M0) that drives the second work implement (18), and the control means (141) that, in the energy saving mode, maintains the maximum rotation speed of the electric motor (4) and reduces the maximum rotation speed of the second electric motor (M0). Effect of the Invention

[0012] According to the invention of claim 1, by providing inside the bonnet (6) a first battery (123), a switching unit (124) that controls switching between power supply to and from the first battery (123) and power supply to and from the second battery (101), a cooler (132) in front of the switching unit (124), and a heat exchanger (131) that cools the refrigerant used to cool the electric motor (4), it is possible to prevent excessive temperature rise in electronic devices accommodated in the bonnet.

[0013] According to the invention recited in claim 2, in addition to the effects of the invention recited in claim 1, the power supply cord (127) can be stored on the side of the bonnet (6), thereby reducing the occurrence of accidents in which an operator gets caught on the power supply cord (127) and is injured.

[0014] According to the invention of claim 3, in addition to the effects of the invention of claim 1, by arranging the current detector (107), the molded case circuit breaker (106), the second switching circuit (110), and the transformer (113) in close proximity to each other, the harness can be shortened, power loss can be suppressed, and energy can be saved.

[0015] According to the invention of claim 4, in addition to the effects of the invention of claim 1, by providing an energy saving mode that reduces the power supply rate of the first battery (123), it is possible to suppress a temperature rise of the first battery (123), improve power efficiency, and achieve energy saving.

[0016] According to the invention of claim 5, in addition to the effects of the invention of claim 1, by providing an energy saving mode that reduces the power receiving speed of the second battery (101), it is possible to suppress a temperature rise of the second battery (101), improve power efficiency, and achieve energy saving.

[0017] According to the invention described in claim 6, in addition to the effects of the invention described in claim 4 or 5, in the energy saving mode, the maximum rotation speed of the electric motor (4) is maintained and the maximum rotation speed of the second electric motor (M0) is reduced, thereby making it possible to reduce power consumption while maintaining the driving performance of the work vehicle. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is an explanatory diagram of a tractor according to an embodiment, and is an explanatory diagram of a state in which an additional battery is attached in place of a working machine. [Diagram 2] FIG. 2 is a side view of the tractor shown in FIG. [Diagram 3] FIG. 3 is an explanatory diagram of the additional battery frame. [Figure 4] FIG. 4 is a functional block diagram of the battery control and connection according to the embodiment. [Diagram 5] FIG. 5 is a diagram illustrating a main portion of an external connection terminal according to an embodiment. [Figure 6] FIG. 6 is an explanatory diagram of the main parts inside the bonnet of the tractor according to the embodiment, in which the storage box and the bonnet are omitted. [Figure 7] FIG. 7 is an explanatory diagram of another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] FIG. 1 is an explanatory diagram of a tractor according to an embodiment, and is an explanatory diagram of a state in which an additional battery is attached in place of a working machine. FIG. 2 is a side view of the tractor shown in FIG. 1 and 2, a tractor 1 as an example of a work vehicle of the present invention is equipped with front wheels 2, 2 and rear wheels 3, 3 at the front and rear of a traveling body (an example of a vehicle main body) 1a. A traveling motor 4 as an example of an electric motor is mounted below a driver's seat 8 at the rear of the traveling body 1a. The rotational power of the traveling motor 4 is appropriately reduced by a speed change device in a transmission case (not shown) and is configured to be transmitted to the front wheels 2, 2 and the rear wheels 3, 3.

[0020] A work machine such as a tiller for cultivating the ground (field) behind the tractor 1 and a container (sometimes called a collector) for storing cut grass can be attached to the rear of the tractor 1, and the work machine is driven by power transmitted via a PTO shaft (rear PTO shaft) not shown. Drive is transmitted to the PTO shaft in the embodiment from a PTO motor (not shown) as an example of a second electric motor. In the tractor 1 of the embodiment, a lawnmower 18 is supported between the front wheels 2 and the rear wheels 3 as an example of a second working machine. Power is transmitted to the lawnmower 18 via a second PTO shaft (mid PTO shaft) (not shown). The second PTO shaft is driven by a PTO motor, but it is also possible to separately install a motor dedicated to the second PTO shaft. In this specification, the left and right sides in the forward direction of the tractor 1 are referred to as the left and right sides, respectively, and the forward direction is referred to as the front side and the reverse direction is referred to as the rear side.

[0021] A driver's seat (operating seat) 8 is disposed at the top of the traveling vehicle body 1a, and a steering wheel 10 is disposed in front of the driver's seat 8. Also disposed in front of the driver's seat 8 are a display panel (meter panel) including a speedometer (not shown), various operation switches (not shown), and the like. Disposed in front of the driver's seat 8 at the bottom are driving operation tools such as a brake pedal 12 (see FIG. 6) and an accelerator pedal 13 having a forward pedal and a reverse pedal.

[0022] In Fig. 1, lift arms 15, 15 are pivotally mounted to the rear of the traveling body 1a. Lift rods (not shown) are interposed and connected between the lift arms 15, 15 and lower links 16, 16, and a container, a tiller, or other working machine can be attached to the rear of the lower links 16, 16.

[0023] The lift arm 15 is driven by a hydraulic cylinder (not shown). When the hydraulic pressure of the hydraulic cylinder increases and the lift arms 15, 15 are rotated to the upward direction, the working machine (container, etc.) is raised via the lift rod, lower link 16, etc. When the hydraulic oil is discharged and the hydraulic pressure decreases, the lift arms 15, 15 are lowered. In addition, the working machine mounted to the rear of the traveling body 1a, i.e., the working machine to which drive is transmitted from a PTO shaft (not shown) extending along the lower link 16, is not limited to rotary tilling equipment for agricultural work, but includes working machines such as plows, seed sowing machines, seedling transplanters, fertilizer spreaders, and pesticide spreaders.

[0024] 1 and 2, in the tractor 1 of the embodiment, an additional battery 101 as an example of a second battery can be attached to the lower link 16 as an example of a work machine support section and the lift arm 15 instead of the work machine. The lift arm 15 and the lower link 16 have strength and rigidity sufficient to support a relatively heavy work machine such as a tiller, and are strong enough to support the additional battery 101 even if it is heavy. The additional battery 101 has a protective case 101a as an example of a container. The protective case 101a is formed so as to cover the entire additional battery 101. Note that, while it is preferable that the upper surface of the protective case 101a is configured without holes or openings to protect against rainwater, it is also possible to form holes or openings on the side surfaces. Forming holes or openings improves the ventilation inside the additional battery 101. This is therefore preferable because it allows the heat generated inside the additional battery 101 to be efficiently dissipated and the inside to be cooled.

[0025] FIG. 3 is an explanatory diagram of the additional battery frame. 2 and 3, an additional battery frame 102 is housed inside the protective case 101a. The additional battery frame 102 has vertical frames 102a that extend in the up-down direction and are arranged at the four corners of the protective case 101a, i.e., front, rear, left and right. Horizontal frames 102b extending in the front-rear direction are supported between the vertical frames 102a. Four sets of horizontal frames 102b are provided in the up-down direction, one on each side. A slide rail 102c extending in the left-right direction is supported on the horizontal frame 102b. A plurality of additional battery bodies 103 are supported on the slide rail 102c.

[0026] The additional battery body 103 of the embodiment can be attached to, detached from, and replaced with respect to the additional battery frame 102 by sliding it in the left-right direction along the slide rail 102c. When the additional battery body 103 is attached to the additional battery frame 102, it is fastened and fixed with bolts (not shown). Note that, although FIG. 3 illustrates a form in which the additional battery body 103 can slide in the left-right direction, the present invention is not limited to this, and it is also possible to adopt a form in which the additional battery body 103 can slide in the front-rear direction. Furthermore, the fixing of the additional battery body 103 to the additional battery frame 102 is not limited to fastening with bolts, and it is also possible to change to a configuration in which the additional battery body 103 can be locked with one touch using a leaf spring, a resin claw, or the like.

[0027] An upper connecting plate 102d detachably connected to the lift arm 15 and a lower connecting plate 102e detachably connected to the lower link 16 are supported on the traveling vehicle body 1a side of the vertical frame 102a. Each connecting plate 102d, 102e is detachably connected to the lift arm 15 and the lower link 16 with a bolt or the like. It is desirable that the connecting plates 102d, 102e have a structure similar to that of the connecting parts to the lift arm 15 and the lower link 16 of a work machine such as a tiller. The additional battery 101 is attached to the lower link 16 or the lift arm 15 and supported in a state where it is suspended above the field surface, but this is not limiting. It is also possible to provide wheels under the additional battery 101 so that the additional battery 101 is also supported by the wheels. By supporting the additional battery with the wheels, the overall weight balance of the tractor 1 is improved. This improves the travelability of the tractor 1 and reduces the risk of accidents such as tipping over.

[0028] Also, the additional battery 101 is preferably attached to the lower link 16 or the lift arm 15, but is not limited to this. For example, it is possible to support the additional battery 101 on a dolly having wheels, and to connect the dolly with a towing hook or a towing wire provided on the traveling body 1a, thereby towing the additional battery 101. It is also possible to attach the additional battery 101 to the lower link 16 or the lift arm 15, and to tow the additional battery 101 installed on the dolly. When towing the additional battery 101, it is desirable to provide a clamp or a hook for protecting and fastening the cables connecting the additional battery 101 side and the traveling body 1a side. Furthermore, the present invention is not limited to towing by means of hooks or cables, but may be connected more firmly than towing by means of couplers or the like.

[0029] FIG. 4 is a functional block diagram of the battery control and connection according to the embodiment. 1, additional connection terminals 104 are formed on the upper part of protective case 101a. The shape of additional connection terminals 104 does not matter, but it is preferable to use standards used in passenger cars (particularly electric cars and hybrid cars), such as J1772, IEC62196-2, CHAdeMO (registered trademark), from the viewpoint of standardizing parts and standards. When the above-mentioned standardized terminal is used as the additional connection terminal 104, the additional battery 101 can be used not only by connecting it to the traveling body 1a, but also when it is removed from the tractor 1. In other words, it is also possible to use the additional battery 101 by directly connecting a commercially available cable to the additional connection terminal 104 of the removed additional battery 101. This increases the degree of freedom of use, making it easier to effectively use in times of disasters and the like, and easier to handle.

[0030] 4, a circuit breaker 106 as an example of a safety circuit and a hall sensor (magnetic sensor) 107 as an example of a current detector that detects a current flowing between the additional connection terminal 104 and the additional battery main body 103 are connected between the additional connection terminal 104 and the additional battery main body 103. The circuit breaker 106 and the hall sensor 107 are disposed inside the protective case 101a. The additional battery main body 103 and the hall sensor 107, the hall sensor 107 and the circuit breaker 106, and the circuit breaker 106 and the additional connection terminal 104 are connected by high-voltage power supply lines 108 (108a to 108c) as an example of a connection cable.

[0031] An additional battery manager 110 as an example of a second switching circuit is connected to the additional battery body 103, the Hall sensor 107, and the molded case circuit breaker 106. The additional battery manager 110 is configured by a small information processing device, a so-called microcomputer. The additional battery manager 110 is also electrically connected to a network card 111 as an example of a communication circuit, a touch panel 112 as an example of an additional input device, and a switching unit 124 (described later) on the traveling vehicle body 1a side. The additional battery manager 110 is connected to each part by a CAN (Controller Area Network) 114 as an example of a communication line. Note that the connection is not limited to the CAN, and any conventionally known communication line for transmitting and receiving information can be used. Note that the control power source 113 that drives the additional battery manager 110 is configured by a DC / DC converter that transforms the power of the additional battery body 103 as an example, but a dry cell or the like can also be used.

[0032] The additional battery manager 110 receives the detection result of the Hall sensor 107. Furthermore, when an abnormal state such as an overcurrent is detected based on the detection result of the Hall sensor 107, the additional battery manager 110 controls the connection / disconnection of the wiring circuit breaker 106 to protect each part of the additional battery 101. Furthermore, the additional battery manager 110 controls switching between power supply and charging of the additional battery main body 103. Furthermore, the additional battery manager 110 can display the state of the additional battery main body 103 on a touch panel 112 as an example of a display unit, and can receive input from the touch panel 112 as an example of an input unit.

[0033] Furthermore, the additional battery manager 110 communicates with the outside via the network card 111. For example, when power is to be supplied from the tractor 1 to the outside, it is preferable that the user checks on the touch panel 112 and manually inputs permission for external power supply. That is, when permission for external power supply is input from the touch panel 112, the permission is transmitted to the protection circuit on the house side via wireless communication via the network card 111, the protection circuit on the house side is switched to power supply from the external power source (tractor 1), and when the tractor 1 side receives via wireless communication that the switching on the house side has been completed, power supply from the tractor 1 is started, thereby enabling safe power supply.

[0034] In addition, when the tractor 1 supplies power to a facility such as a house, if the power consumption of the facility is large, the load on the tractor 1 side will be large. Therefore, it is preferable to provide multiple switches in the protection circuit on the facility side and to switch between supplying and not supplying power for each switch depending on the load. For example, if a heated house used for growing strawberries or other fruits experiences a power outage or the power supply becomes unstable, it is possible to supply power from the tractor 1. However, if the power consumption is high due to the operation of the ventilation fan and opening and closing windows of the heated house, it is preferable to protect the heated house with a protection circuit. In addition, if the power supply becomes unstable, it is preferable to control the protection circuit to switch so that the shortage is supplied from the tractor 1 only when there is a temporary shortage of power. In addition, it is not limited to supplying the shortage of power for the entire heated house with the tractor 1, but it is preferable to switch the protection circuit so that power is supplied only to the power supply destinations with high priority in the heated house.

[0035] The switching of the protection circuit is preferably performed by wireless communication via touch panel 112 or a main body display 125 (described later), but it is also possible to configure the switch to be turned on and off manually. Note that it is preferable to sound a buzzer or display on touch panel 112 when the switch is switched or when a power shortage or power outage occurs. It is also possible to configure the system so that the user can confirm and give instructions on a smartphone, tablet terminal, or the like, as an example of a mobile terminal, to permit power supply from the tractor 1, to switch the protection circuit on the house side, and to start power supply from the tractor 1. It is also possible to configure the system so that the user can give instructions via the touch panel 112, a mobile terminal, or the like, to prohibit power supply from the tractor 1, to prohibit charging the tractor 1, and the like.

[0036] 2, the protective case 101a of the embodiment also has a function of protecting the additional battery main body 103, the additional battery manager 110, and the like housed therein from dust and water. In the embodiment, the Hall sensor 107, the circuit breaker 106, the additional battery manager 110, and the like are arranged at the upper part inside the protective case 101a. By arranging the electronic devices such as the Hall sensor 107 at the upper part, they become easier to access during maintenance, improving maintainability. In particular, among the devices in the protective case 101a, the molded case circuit breaker 106 and the control power supply 113 (DC / DC converter) are devices that are likely to generate heat. Therefore, by arranging these devices at the top, the rising air current caused by the heat is released to the outside more quickly, and the heat is more likely to be dissipated, compared to when these devices are arranged at the bottom. This suppresses the rise in temperature inside the protective case 101a, and suppresses the risk of a change in electrical resistance, an increase in power consumption, a decrease in the operating efficiency of the devices, or thermal runaway.

[0037] In addition, the length of the harness (connection cable) connecting the hall sensor 107, molded case circuit breaker 106, additional battery manager 110, control power supply 113, and additional connection terminal 104 is shortened by arranging them close to each other. By shortening the length of the harness, heat generation and power loss in the harness are suppressed, improving power consumption (energy saving). It is preferable to install the Hall sensor 107, the circuit breaker 106, the additional battery manager 110, etc. inside the protective case 101a of the additional battery 101, but this is not limitative and they can be installed in any position depending on the design, specifications, etc. For example, they can be installed in the space below the driver's seat 8 of the traveling vehicle body 1a.

[0038] In the embodiment, power is supplied to and received from the additional battery body 103 via the high-voltage power supply line 108, and the control system is via the CAN 114, and the high-voltage power supply line 108 and the CAN 114 are separated from each other. This prevents noise generated on the high-voltage power supply line 108 from adversely affecting the CAN 114.

[0039] Furthermore, in the embodiment, the touch panel 112 is installed on the upper part of the protective case 101a. Therefore, when the tractor 1 is stopped, the user can get off and check the status (remaining battery charge, charging status, etc.) of the additional battery 101 (and the main battery 123 described later) from outside the additional battery 101. Also, instructions such as permission for external power supply or prohibition of external power supply, permission for charging from an external power source or prohibition of charging, etc. can be input through the touch panel 112. The position of the touch panel 112 is not limited to the upper part of the protective case 101a, and can be changed to any position according to the design, specifications, etc. For example, it can be provided on the upper part of the fender of the traveling vehicle body 1a. By providing it on the upper part of the fender, it becomes easier for the operator to check and operate the touch panel 112 while seated in the driver's seat 8.

[0040] Note that, when the cables connecting the additional battery 101 and the traveling vehicle body 1a are exposed, for example, on the right side of the traveling vehicle body 1a, it is preferable to install the touch panel 112 on the right fender. This makes it difficult to get in and out of the vehicle from the right side of the driver's seat 8 due to the touch panel 112 being in the way, and prevents workers from catching the cables when getting in and out of the vehicle, causing them to break or be damaged. Therefore, when it is desired to restrict getting in and out of the driver's seat 8 from a specific direction (right or left), it is preferable to install the touch panel 112 on the side to be restricted.

[0041] 1, 2, and 4, one end of a connection cable 121 is connected to the additional connection terminal 104. The connection cable 121 extends toward the bonnet 6 of the traveling vehicle body 1a. The connection cable 121 is preferably routed along the underside of the floor step 1b or fender 1c of the traveling vehicle body 1a. By routing the connection cable 121 along the underside of the fender 1c or the like, it is possible to prevent rainwater from entering the connection cable 121 when a worker moves on the floor step 1b, and to prevent the connection cable 121 from breaking when it gets caught. When routing the connection cable 121, it is preferable to fix it with a U-shaped hook, a U-shaped bracket, a cable clamp, or the like.

[0042] A main battery (an example of a first battery) 123 is accommodated inside the bonnet 6. A switching unit 124 to which the other end of the connection cable 121 is connected is also provided inside the bonnet 6. The switching unit 124 is configured with a microcomputer including an electronic circuit, similar to the additional battery manager 110. When the tractor 1 is stopped, the switching unit 124 switches between charging from an external power supply facility and supplying power to the external facility. Furthermore, the switching unit 124 switches between supplying / not supplying power to the traveling motor 4 and supplying / not supplying power to the PTO motor M0 when traveling for work.

[0043] When the traveling motor 4 or the PTO motor M0 is used as a regenerative motor during traveling for work, the switching unit 124 switches when charging the main battery 123 with power generated by the regenerative motor. The switching unit 124 also performs voltage transformation when the voltage of the main battery 123 or the additional battery 101 differs from the voltage of the traveling motor 4 or the external power supply facility. In addition, since there is a risk of an accident if the tractor 1 starts moving when charging from an external power source or when external power is supplied, it is desirable to configure the switching unit 124 so that, for example, charging from an external power source or external power supply cannot be received unless the tractor 1 is stopped. As the switching unit 124 of the embodiment, it is possible to use a modified DCMPU (Direct Current Multi Power Unit) used in passenger cars or the like that do not have PTO shafts S1, S2.

[0044] The switching unit 124 is connected to a main body display 125, which is an example of a display device, via the CAN 114. In this embodiment, the main body display 125 is installed near the steering wheel 10 in front of the driver's seat 8 (on the meter panel). Like the touch panel 112, the main body display 125 can display the status of the main battery 123 and the additional battery 101 and allow the user to manually input information. In addition, the main body display 125 is also provided with an emergency stop button for the switching unit 124, which can stop charging the batteries 103, 123 and external power supply in the event of an emergency. Therefore, the user can check the remaining capacity and charging status of the main battery 123 and the additional battery 101 while seated in the driver's seat 8.

[0045] The main body display 125 is not limited to being placed on the meter panel, but may be placed above the bonnet 6. The main body display 125 is not limited to being fixedly supported. For example, the main body display 125 may be supported via a member that rotates with respect to the meter panel or the like, or may be supported by a multi-joint arm. By employing a rotating type or multi-joint arm, the main body display 125 can be checked not only from the driver's seat 8, but also when the driver has got out of the vehicle. Furthermore, like the touch panel 112, when it is desired to restrict getting on and off the driver's seat 8 from a specific direction, the main body display 125 is preferably installed on the side where the restriction is desired.

[0046] FIG. 5 is a diagram illustrating a main portion of an external connection terminal according to an embodiment. An external connection terminal 126 is connected to the switching unit 124 via an external connection cable (an example of a power supply cord) 127. The external connection terminal 126 is configured to be capable of inputting and outputting control signals via the CAN 114. In other words, via the external connection terminal 126, it is possible to detect the presence or absence of an external connection, and control switching between charging from an external facility and power supply to the external facility. 5, in external connection terminal 126 according to the embodiment, cylindrical connector portion 126a is formed with drainage hole 126b penetrating connector portion 126a in parallel with the longitudinal direction of external connection cable 127. Therefore, even if rainwater gets on connector portion 126a, it is quickly drained from drainage hole 126b, and the occurrence of leakage current or the like in external connection terminal 126 is suppressed.

[0047] External connection cable 127 is stored in a wound state inside a storage box (one example of a power supply case) 128 supported on a side portion (the right side in this embodiment) of bonnet 6. External connection cable 127 is configured so that it can be wound and pulled out by a conventionally known spiral spring type winding reel. Therefore, by storing external connection cable 127 in storage box 128, it is possible to improve waterproofing and reduce the risk of electric leakage compared to a configuration in which external connection cable 127 is exposed to the outside.

[0048] In the embodiment, the external connection cable 127 is stored in the storage box 128 outside the bonnet 6, but the present invention is not limited to this. The external connection cable 127 can also be stored inside the bonnet 6. In this case, by utilizing the fact that the bonnet 6 can be opened and closed for maintenance of the main battery 123 and the like, the bonnet 6 can be opened to expose the external connection cable 127 inside the bonnet 6 and make it available for use. For waterproofing, it is preferable to provide a storage box 128 and to store the external connection cable 127 inside the bonnet 6, but it is also possible to have the external connection cable 127 exposed to the outside. In this case, it is preferable to provide, for example, a hook or the like for hanging and holding the external connection cable 127 wound around the side of the bonnet 6.

[0049] Even when the external connection cable 127 is housed inside the bonnet 6, it is preferable to easily ensure the internal space of the bonnet 6 by configuring the external connection cable 127, which has a large wire diameter, to be pulled out from the bottom of the bonnet 6. When configured to be pulled out from below, it is preferable to provide a guide so that the external connection cable 127 does not come into contact with the ground. Although the above embodiment shows a configuration in which only one external connection cable 127 is provided, it is also possible to provide two or more external connection cables. When two external connection cables are provided, one can be used for charging and the other for power supply.

[0050] When using external connection cable 127, a user holds and pulls out external connection terminal 126, thereby pulling out external connection cable 127 wound around storage box 128. With external connection cable 127 pulled out, external connection terminal 126 can be connected to a connection terminal of an external power supply facility or a power-receiving facility. The external connection terminal 126 can be the same as the additional connection terminal 104 (CHAdeMO (registered trademark), etc.), or it can be a single-phase 100V outlet or a three-phase 200V outlet by installing a transformer, converter, inverter, etc. between the switching unit 124 or the switching unit 124 and the external connection cable 127 to perform transformation or AC-DC conversion.

[0051] Therefore, by pulling out the external connection cable 127, it is possible to connect the tractor 1 to the outside, and no cable is required on the external side. Therefore, in the event of an emergency such as a power outage or disaster, the tractor 1 can be moved to a location where power is needed, and even if no cable is prepared on the facility side, it is possible to extend the external connection cable 127 and supply power. Furthermore, in the tractor 1 of the embodiment, by mounting not only the main battery 123 but also the additional battery 101, it is possible to dramatically increase the overall electric capacity. Therefore, compared to an electric vehicle or the like that is mounted only with the main battery 123, it is possible to supply electric power in a large capacity for a long period of time. Therefore, there is a high possibility that electric power can be continuously supplied from the tractor 1 until the power is restored.

[0052] In particular, agricultural machinery such as the tractor 1, combine harvester, and seedling transplanter is used only for a limited period of the year. That is, the tractor 1 is used only during the plowing and land preparation periods, the combine harvester is used only during the harvesting period, and the seedling transplanter is used only during the rice planting period. Therefore, depending on the size of the field, each work vehicle is used only for a few days to at most about one month in a year, and the rest of the time it is on standby in a warehouse or barn, and the standby period is long. Therefore, during the standby period when it is not used, it is possible to remove the work machine and attach the additional battery 101, and charge the main battery 123 and the additional battery 101 with electricity generated by a solar power generation device or the like. Once charging with solar power generation is set up, the burden on the worker during charging is light. And by using the batteries 101, 123 that have been charged in an emergency, the possibility of continuing to use electricity until the power is restored is increased. Therefore, the work vehicle that is on standby for a long period of time can be effectively used in an emergency.

[0053] Furthermore, by using an automatic winding system with a power spring for external connection cable 127 in the embodiment, it is easier to store and pull out external connection cable 127 than when an operator manually winds or folds external connection cable 127 for storage. It is also possible to prevent situations where the cable cannot be stored due to improper folding, or where a part of the cable protruding from the storage space interferes with wheels 2, 3. In order to prevent contact between the external connection cable 127 and the accelerator pedal 13, it is preferable to provide a plate or the like on the outside of the accelerator pedal 13.

[0054] Although the embodiment in which one external connection cable 127 and one external connection terminal 126 are provided in the tractor 1 has been exemplified, the present invention is not limited to this. That is, it is also possible to provide an external connection terminal separately and additionally in the traveling body 1a of the tractor 1 or the additional battery 101. As the additional external connection terminal, for example, any one or more of a cigarette lighter socket, a USB (Universal Serial Bus) socket, a single-phase 100V outlet, a three-phase 200V outlet, etc. can be adopted. The position at which the additional external connection terminal is provided is not particularly limited, and it can be provided at any position according to the design, specifications, ease of use, ease of understanding of the position, rainwater / dust countermeasures, leakage countermeasures, etc., such as the vertical surface of the fender of the traveling body 1a, the foot of the driver's seat 8, the periphery of the steering wheel 10 (such as the cover of the meter panel), the outer surface of the protective case 101a of the additional battery 101, the upper surface of the bonnet 6, the inside of the bonnet 6, the front grille of the bonnet 6, etc. When multiple types of external connection terminals are used, the positions of the external connection terminals can be made easier to understand by arranging them side by side, or they can be arranged at separate locations to make it difficult to confuse the types.

[0055] When multiple external connection terminals are provided, it is possible to configure the multiple external connection terminals in a way that allows charging (power supply) from one external connection terminal while external power is being supplied from another external connection terminal (pass-through), or to configure the terminals in a way that does not allow charging (power supply) when external power is being supplied from one external connection terminal while charging (power supply) is being attempted from another external connection terminal (non-pass-through), or to configure the terminals in a way that interrupts power supply and performs charging (non-pass-through).

[0056] FIG. 6 is an explanatory diagram of the main parts inside the bonnet of the tractor according to the embodiment, in which the storage box and the bonnet are omitted. 6, inside the bonnet 6, a switching unit 124 is disposed above a main battery (high voltage battery) 123. A radiator 131, which is an example of a heat exchanger, is disposed in front of the main battery 123. The radiator 131 cools a refrigerant that cools the traveling motor 4. The refrigerant is transferred through a pipe (not shown) that extends from the traveling motor 4 below the driver's seat 8 to the radiator 131 at the front inside the bonnet 6.

[0057] A cooling fan 132, which is an example of a cooler, is disposed in front of the radiator 131. The cooling fan 132 draws in outside air from an opening in a grill portion on the front surface of the bonnet 6, and sends the outside air to the radiator 131 and main battery 123 at the rear. The outside air drawn into the bonnet 6 is exhausted from an exhaust port (not shown) formed on the left side surface of the bonnet 6. An auxiliary battery (low-voltage battery) 133, which is an example of a third battery, is disposed in front of the cooling fan 132. The auxiliary battery 133 supplies power not to devices that operate at high output and high voltage, such as the travel motor 4 and the PTO motor, but to devices that operate at relatively low voltage, such as the switching unit 124, the cooling fan 132, various sensors, and an operation panel. Therefore, in this embodiment, the auxiliary battery 133 is also cooled by the outside air of the cooling fan 132.

[0058] Therefore, in the tractor 1 of the embodiment, the cooling fan 132 is operated by power supply from the auxiliary battery 133 to cool the auxiliary battery 133, the switching unit 124, the main battery 123, etc. In other words, for the devices housed in the bonnet 6 that require a minimum level of protection for the operation of the tractor 1, the cooling by the cooling fan 132 prevents the performance from decreasing due to heat, and a safe state is maintained. When external power is supplied from the tractor 1 in the event of a disaster such as an earthquake, safety during the power supply period is not necessarily guaranteed. That is, the power supply destination may be manned, but may also be unmanned with only a storage battery. In this situation, if a secondary disaster (aftershock, collapse of a building, power outage, fire, etc.) occurs during power supply, the tractor 1 and the operator need to escape. When attempting to drive the tractor 1 to escape, it is dangerous if the main battery 123 or the auxiliary battery 133 becomes too hot to start. In contrast, in the tractor 1 of the embodiment, the auxiliary battery 133 and the like are stably cooled by the cooling fan 132, and measures are taken to prevent heat from building up inside the hood 6 and to prevent abnormalities from occurring.

[0059] In particular, in the tractor 1 of the embodiment, the main battery 123 and the additional battery 101 are separated, and even if the performance of the additional battery 101 deteriorates due to heat, the inside of the bonnet 6 is cooled. Therefore, when a secondary disaster or the like occurs, problems are unlikely to occur with starting, running, or escaping the tractor 1. If the main battery 123 is placed outside the bonnet 6 (for example, below the driver's seat 8), the main battery 123 is unlikely to be cooled by the cooling fan 132, and there is a risk of heat building up during external power supply. Even in this case, at least the auxiliary battery 133 is cooled by the cooling fan 132, and the auxiliary battery 133 is likely to perform sufficiently. Therefore, in the event of a secondary disaster or the like, although it may be difficult to travel using the power of the auxiliary battery 133, it is possible to take measures such as safely stopping the power supply to the outside, locking the tractor 1, and transmitting a signal to headquarters to confirm the safety of the operator.

[0060] In addition, the auxiliary battery 133 is preferably housed inside the bonnet 6, but is not limited to this. It can be placed in any position, such as under the driver's seat 8. The location of the exhaust port is not limited to the side, and it can be on the top or bottom of the bonnet 6, but it is preferable to provide it on the side because rainwater can easily get in through the exhaust port if it is located on the top, and splashed mud can block the exhaust port if it is located on the bottom. Also, having the exhaust port on the side makes maintenance easier, and a high position on the side of the bonnet 6 is preferable because it exhausts air whose temperature has increased after passing through the radiator 131, etc.

[0061] The position of the cooling fan 132 is preferably, but not limited to, located at the front in the internal space of the bonnet 6. For example, it may be located above the switching unit 124 or on the inner side of the side of the bonnet 6. Furthermore, the position of the switching unit 124 is not limited to above the main battery 123, and can be changed to any position, such as behind or in front of the radiator 131. In this case, it is also possible to have a configuration in which a refrigerant pipe connected to the radiator 131 comes into contact with the switching unit 124 to cool the switching unit 124. Also, it is possible to arrange a water pump that circulates the refrigerant near the cooling fan 132 at the front of the bonnet 6 to suppress a rise in temperature of the water pump.

[0062] FIG. 7 is an explanatory diagram of another embodiment of the present invention. The cooling fan 132' can also be built into the lawnmower 18. In FIG. 7, the lawnmower 18 has a rotating shaft 18a to which drive is transmitted from the second PTO shaft (mid PTO shaft) S2. A mowing blade 18b, which is an example of a mowing part, is supported on the lower end of the rotating shaft 18a. A cooling fan 132' is disposed above the mowing blade 18b, with a partition plate 18a1 sandwiched therebetween. The upper and side portions of the cooling fan 132' are covered by a mower deck 18c, which is an example of a protective part. An intake port 18d is formed in the mower deck 18c near the rotating shaft 18a. An exhaust port 18e is formed on the side of the upper portion of the mower deck 18c. The cooling fan 132' in the form shown in FIG. 7 is configured as a sirocco fan. Therefore, when the cooling fan 132' rotates, air is sucked in through the intake port 18d and exhausted to the exhaust port 18e. Therefore, warm air in the space inside the bonnet 6 above the lawnmower 18 can be exhausted, and the space inside the bonnet 6 can be cooled.

[0063] In the embodiment shown in Fig. 7, the rotating shaft 18a of the lawnmower 18 is shared and used as the rotating shaft of the cooling fan 132'. This simplifies the configuration compared to a configuration in which a dedicated rotating shaft is provided to drive the cooling fan 132'. Also, by providing the cooling fan 132' that draws in air downward above the cutting blade 18b, the movement of cut fine grass, dust, etc. toward the bonnet 6 above is prevented. The radiator 131 can be installed on the upper surface of the mower deck 18c. Alternatively, the radiator 131 can be omitted and a pipe through which the refrigerant is transported can be supported directly on the upper surface of the mower deck 18c, that is, the mower deck 18c can be used as a heat exchanger. Also, the cooling fan 132' is preferably a sirocco fan, but it may also be a centrifugal fan or an axial fan.

[0064] 4, a main controller 141 as an example of a control means outputs control signals to controlled elements such as the switching unit 124, the travel motor 4, the PTO motor M0, etc. The main controller 141 also receives control signals from signal output elements such as a first temperature sensor SN1 arranged inside the hood 6, a second temperature sensor SN2 arranged near the additional battery main body 103, the main body display 125, the switching unit 124, etc. The main controller 141 in the embodiment is configured with a microcomputer.

[0065] The temperature detection means 142 of the main controller 141 detects the temperature (first temperature) inside the hood 6 based on the detection result of the first temperature sensor SN1. Also, the temperature detection means 142 of the embodiment detects the temperature (second temperature) of the additional battery main body 103 based on the detection result of the second temperature sensor SN2. The mode switching means 143 switches between the normal mode and the energy saving mode based on the detection result of the temperature detection means 142. In the embodiment, the mode switching means 143 switches to the energy saving mode when the first temperature or the second temperature reaches a predetermined temperature (threshold value), and switches to the normal mode when the first temperature or the second temperature does not reach the predetermined temperature (threshold value).

[0066] In the energy saving mode of the embodiment, when the first temperature reaches a threshold value, a control signal is sent to the switching unit 124 to reduce the power supply rate (current value per unit time) to a predetermined energy saving power supply rate if the main battery 123 is supplying power, and to reduce the charging rate (current value per unit time) to a predetermined energy saving charging rate if the main battery 123 is charging. In addition, when the second temperature reaches the threshold value, a control signal is sent to the additional battery manager 110 to reduce the power supply rate (current value per unit time) to a predetermined energy-saving power supply rate if the additional battery body 103 is supplying power, and to reduce the charging rate (current value per unit time) to a predetermined energy-saving charging rate if the additional battery body 103 is charging.

[0067] In the embodiment, when the power saving mode is switched to based on the detection result of the first temperature or the second temperature, the maximum rotation speed of the PTO motor M0 is limited to a value lower than the maximum rotation speed in the normal mode. The maximum rotation speed in the power saving mode is preferably set to the limit rotation speed at which the lawn mower 18 can cut and collect grass. At this time, the maximum rotation speed of the traveling motor 4 is controlled to be maintained. In the embodiment, the maximum rotation speed of the traveling motor 4 is maintained, but it is also possible to limit the maximum rotation speed of the traveling motor 4. In addition, in the power saving mode, it is also possible to limit the acceleration at the time of starting or increase the braking force of the regenerative brake while maintaining the maximum rotation speed of the traveling motor 4, thereby suppressing power consumption during acceleration.

[0068] If neither the first temperature nor the second temperature reaches the threshold, the mode is changed to the normal mode, and the power supply speed of the main battery 123 and the additional battery main body 103 is set to a normal power supply speed / normal charging speed that is higher than the energy saving power supply speed / energy saving charging speed. The maximum rotation speed of the PTO motor M0 is also switched to the maximum rotation speed in the normal mode that is higher than the maximum rotation speed in the energy saving mode.

[0069] Therefore, when the temperature of the batteries 103, 123 rises and the efficiency of power consumption drops, the power receiving speed is limited to suppress power loss, and the maximum rotation speed of the PTO motor M0 is reduced to suppress heat generation during operation, thereby suppressing overall heat generation. This suppresses the temperature rise of the batteries 103, 123, and allows the temperature of the batteries 103, 123 to be lowered to an efficient temperature. This improves power consumption.

[0070] In the embodiment, the configuration is exemplified in which the normal mode and the energy saving mode are automatically switched based on the detection results of the temperature sensors SN1 and SN2, but the present invention is not limited to this. For example, it is also possible to configure the mode to be switched in response to manual input by the operator using a button, switch, dial, etc. By enabling manual input by the operator, it is possible to work under the power consumption conditions intended by the operator.

[0071] Furthermore, when power is being supplied or the external connection cable 127 is connected to the outside, the main controller 141 in the embodiment controls so that no actuator operation, such as driving or operation of the PTO motor M0, is performed even if an input operation is performed to operate the accelerator pedal 13, the operation switch of the PTO motor M0, the work machine, or the lawnmower 18, thereby ensuring safety. Furthermore, when the remaining charge of the batteries 103, 123 falls below a preset value while the tractor 1 is supplying power to the outside, the main controller 141 sends a control signal to the switching unit 124 to automatically interrupt the power supply. In addition, the main controller 141 can also perform control so as to supply power to the outside only during the period when the parking brake is locked or during the period when no operation command is issued to the travel motor 4 or the PTO motor M0. [Explanation of symbols]

[0072] 1...Work vehicle, 1a…Vehicle body, 2,3...Travel gear, 4...Electric motor, 6…Bonnet, 15,16...Work equipment support part, 18…Second working machine, 101…second battery, 106…Circuit breaker, 107...Current detector, 110...second switching circuit, 113…Transformer, 123…first battery, 124...Switching unit, 127...power supply cord, 128…Power supply case, 131...heat exchanger, 132...Cooler, 141...Control means, M0: second motor, SN1: first temperature sensor; SN2...Second temperature sensor.

Claims

1. A vehicle body (1a); an electric motor (4) for driving the running device (2, 3) of the vehicle body (1a); A bonnet (6) disposed at the front of the vehicle body (1a); a first battery (123) disposed inside the bonnet (6); A second battery (101) supported by the vehicle body (1a); a switching unit (124) for controlling switching between power supply to and from the first battery (123) and power supply to and from the second battery (101), the switching unit (124) being accommodated in the bonnet (6); a cooler (132) arranged in front of the switching unit (124) and cooling the inside of the bonnet (6); a heat exchanger (131) arranged in the bonnet (6) and corresponding to the cooler (132), for cooling a refrigerant for cooling the electric motor (4); A work vehicle comprising:

2. a power supply case (128) for accommodating a power supply cord (127) for supplying power to the first battery (123), the power supply case (128) being disposed on a side of the bonnet (6); The work vehicle according to claim 1, further comprising:

3. A work machine supported by the vehicle body (1a) for performing work on a farm field; a work machine support portion (15, 16) that detachably supports the work machine, the work machine support portion (15, 16) being capable of mounting the second battery (101) in place of the work machine; a current detector (107) connected to the second battery (101) for detecting a current; a circuit breaker (106) connected to the current detector (107) for cutting off the current when an overcurrent is detected; A second switching circuit (110) that performs switching control of power supply and reception of the second battery (101); A transformer (113) for transforming the power supplied to the second switching circuit (110); Equipped with The current detector (107), the molded case circuit breaker (106), the second switching circuit (110), and the transformer (113) are arranged in close proximity to each other and above the second battery (101).

2. The work vehicle according to claim 1 .

4. A first temperature sensor (SN1) for detecting a temperature inside the bonnet (6); a control means (141) for switching to an energy saving mode in which a power receiving speed of the first battery (123) is reduced when the temperature detected by the first temperature sensor (SN1) reaches a predetermined temperature; The work vehicle according to claim 1, further comprising:

5. a second temperature sensor (SN2) for detecting the temperature of the second battery (101); a control means (141) for switching to an energy saving mode in which a power supply rate of the second battery (101) is reduced when the temperature detected by the second temperature sensor (SN2) reaches a predetermined temperature; The work vehicle according to claim 1, further comprising:

6. a second working machine (18) supported by the vehicle body (1a) and configured to perform work on a farm field; a second electric motor (M0) for driving the second working machine (18); the control means (141) for maintaining a maximum rotation speed of the electric motor (4) and reducing a maximum rotation speed of the second electric motor (M0) in the energy saving mode; 6. The work vehicle according to claim 4 or 5, further comprising:

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