Work vehicle

Abstract

A work vehicle comprising a travel device (B), an engine (E), an electric motor (M), and a battery (T) that supplies electric power to the electric motor (M), wherein the engine (E) supplies motive power to the travel device (B) and / or charges the battery, the electric motor (M) supplies motive power to at least the travel device (B), and when traveling in a region in which the operation of the engine (E) is limited, the engine speed of the engine (E) is set to an idling speed or lower and travel is performed using the motive power from the electric motor (M).

Description

Work vehicle

[0001] The present invention relates to a work vehicle suitable for moving on, for example, slopes or uneven ground with bumps.

[0002] Conventionally, the above-mentioned work vehicle has been configured such that a vehicle body is supported by a plurality of running wheels that can be extended and retracted by operating hydraulic cylinders and are driven by a hydraulic motor, and by changing the height of the running wheels, the vehicle body can be run while maintaining its posture even on slopes, etc. Furthermore, this work vehicle is equipped with an engine as a drive source that drives a hydraulic pump, which is a hydraulic supply source (see, for example, Patent Document 1).

[0003] Japanese Patent Application Publication No. 2022-93124

[0004] In the above-mentioned conventional configuration, an engine is installed as a driving source, so when the vehicle is driven for work inside a building such as a greenhouse, the exhaust gas emitted can worsen the working environment, making the vehicle unsuitable for indoor use.

[0005] Therefore, in consideration of environmental issues, it is possible to use an electric motor as a driving source instead of an engine. However, if the vehicle is driven by an electric motor, the electric motor consumes a large amount of power, and therefore ensuring the battery charge amount becomes an issue.

[0006] In particular, work vehicles suitable for traveling on rough terrain, such as those described above, often operate in mountainous areas or other work areas lacking charging facilities, and there is a risk that they will be unable to continue work if the battery is not charged. On the other hand, if a large-capacity battery capable of long-term operation is installed, the vehicle body becomes large and heavy. As a result, for example, in work vehicles that are used to carry cargo, there are disadvantages such as an inability to ensure a sufficient load capacity.

[0007] One possible solution to this problem is to install an engine so that the battery can be charged by the engine. However, if an engine is installed, when the battery runs low during indoor work, the engine must generate electricity, which can worsen the working environment.

[0008] An object of the present invention is to provide a work vehicle that can perform work for long periods of time without increasing the weight of the vehicle body, while avoiding deterioration of the indoor working environment.

[0009] The characteristic configuration of the work vehicle of the present invention is that it is equipped with a traveling device, an engine, an electric motor, and a battery that supplies power to the electric motor, the engine at least supplies power to the traveling device and charges the battery, the electric motor supplies power to at least the traveling device, and when traveling in an area where the operation of the engine is restricted, the engine rotation speed is set below idling rotation speed and the vehicle travels using power from the electric motor.

[0010] According to the present invention, when traveling in an area where engine operation is restricted, such as inside a building, the traveling device is driven by the electric motor. In addition, since the battery that drives the electric motor can be charged by the engine, long-term operation is possible without the need for a large, high-capacity battery.

[0011] Furthermore, when traveling in areas where engine operation is restricted, the engine speed is kept below idling speed, reducing the amount of exhaust gas produced by the engine and making it possible to work in an environment that does not worsen the working environment.

[0012] Therefore, it has become possible to provide a work vehicle that can work for long periods of time without increasing the weight of the vehicle body, while avoiding deterioration of the indoor working environment.

[0013] In the present invention, when the vehicle is traveling in a region where the operation of the engine is restricted, it is preferable to set the engine speed to zero.

[0014] According to this configuration, the generation of exhaust gas from the engine can be eliminated, so that the deterioration of the indoor working environment can be reliably avoided.

[0015] In the present invention, it is preferable that the area in which the operation of the engine is restricted is indoors or an area inside a restricted boundary set a predetermined distance outside the indoors and the boundary between the indoors and outdoors, and that the area in which the operation of the engine is permitted is outdoors or an area outside the restricted boundary.

[0016] With this configuration, the engine speed is limited to idling speed or less not only inside the building but also in the area inside the restricted boundary, for example, between a location a predetermined distance outside the building entrance and the entrance, which effectively prevents engine exhaust gas from entering the building.

[0017] In the present invention, a switching mechanism is provided that can be switched between a first state that allows operation of the engine and a second state that restricts operation of the engine, and it is preferable that the switching mechanism switches to the first state when traveling outdoors and switches to the second state when traveling indoors.

[0018] With this configuration, the switching mechanism switches to the first state outdoors, allowing the engine to operate and charge the battery efficiently, while indoors the switching mechanism switches to the second state, restricting engine operation and preventing the working environment from deteriorating.

[0019] In the present invention, it is preferable to provide a switching command means that can manually switch the switching mechanism between the first state and the second state.

[0020] According to this configuration, the operator can switch the switching mechanism between the first state and the second state by operating the switching command means. As a result, while a configuration in which the switching mechanism is automatically switched in response to various condition determinations, for example, may have the risk of the engine operating unexpectedly due to a determination error, this configuration does not have such a disadvantage and can prevent the engine from operating unexpectedly against the operator's will.

[0021] In the present invention, it is preferable that a charge state detection means for detecting the charge state of the battery and a full charge notification means for notifying that the battery is in a fully charged state are provided, and when the full charge state is notified, the switching mechanism is switched from the first state to the second state by operating the switching command means.

[0022] According to this configuration, the full charge notification means notifies the operator that the battery is fully charged, so the operator can recognize this and can operate the switching command means to switch to the second state at the appropriate timing when the full charge state is notified.

[0023] In the present invention, it is preferable that a charging state detection means is provided for detecting the charging state of the battery, and the switching mechanism switches from the first state to the second state when it determines, based on the detection information of the charging state detection means, that the battery has reached a fully charged state as a result of charging due to operation of the engine.

[0024] With this configuration, when the charge state detection means detects that the battery is fully charged, the control device automatically switches to the charge restriction state. Therefore, when switching from outdoor driving to indoor driving, the operator does not need to perform any special switching operation, and can work indoors without any hassle and without worsening the working environment.

[0025] In the present invention, it is preferable that a vehicle position determination means is provided for determining whether the vehicle is outdoors or indoors, and that the switching mechanism switches to the first state when the vehicle is outdoors and switches to the second state when the vehicle is indoors based on the determination result of the vehicle position determination means.

[0026] According to this configuration, it is automatically determined whether the vehicle is outdoors or indoors, and the control device automatically switches to the appropriate state, either the first state or the second state, depending on the determination result, so there is no risk of the engine being started indoors due to an operator error, making it easy to use.

[0027] In the present invention, when a vehicle enters a building from the outdoors through a door, an open / closed state detection means is provided which detects whether the door is in an open or closed state, and when the open / closed state detection means detects that the door is in an open state, the control device preferably switches from the first state to the second state at a predetermined distance before the door.

[0028] According to this configuration, if the door of the building is open and a work vehicle approaches the door with the engine running, there is a risk of exhaust gas entering the building. Therefore, this configuration makes use of the fact that the position of the work vehicle can be determined, and if the door is open, by switching to the second state a predetermined distance before the door, it is possible to prevent exhaust gas from entering the building.

[0029] In the present invention, it is preferable that a posture determination means is provided for determining whether the vehicle is in an inclined posture, and the switching mechanism switches to the first state if the vehicle is in an inclined posture based on the determination result of the posture determination means, and switches to the second state if the vehicle is not in an inclined posture.

[0030] According to this configuration, when working outdoors, the vehicle often assumes an inclined posture because it travels over rough ground. In contrast, when working inside a building, the ground is often flat. Therefore, with this configuration, the inclined posture of the work vehicle can be automatically switched to either the first or second state, as appropriate, based on the results of the determination.

[0031] In the present invention, it is preferable to provide a charge shortage notification means for notifying that the battery has become in a charge shortage state as a result of use of the electric motor.

[0032] With this configuration, if the battery becomes low on charge while the vehicle is being driven indoors, the operator will know this and can take immediate action, making the vehicle easy to use.

[0033] In the present invention, it is preferable that a support mechanism is provided that supports the multiple traveling devices on the vehicle body so that each can be raised and lowered separately, and that the engine is capable of driving the traveling devices and the support mechanism in place of the electric motor or in cooperation with the electric motor.

[0034] According to this configuration, the power of the engine can be used to supply the hydraulic oil, and the efficiency of using the engine power can be improved.

[0035] In the present invention, it is preferable that a support mechanism is provided for supporting the plurality of traveling devices on the vehicle body so that each can be raised and lowered separately, the plurality of traveling devices and the plurality of support mechanisms are configured to be hydraulically driven, a hydraulic oil supply device is provided for supplying hydraulic oil to the traveling devices and the support mechanisms, and the electric motor is configured to drive the hydraulic oil supply device.

[0036] Compared to the vehicle itself, the vehicle's travel gear and support mechanisms are more susceptible to the adverse effects of moisture, dust, etc., when they come into contact with mud, wet grass, etc. However, with this configuration, because they are hydraulically driven, they are less susceptible to the effects of moisture, dust, etc., compared to, for example, electrically driven means, making it easier to perform stable work travel.

[0037] Fig. 1 is a side view of the work vehicle. Fig. 2 is a plan view of the work vehicle. Fig. 3 is a rear view of the work vehicle. Fig. 4 is a plan view of the support mechanism. Fig. 5 is a side view of the support mechanism. Fig. 6 is a control block diagram. Fig. 7 is a diagram showing the configuration of a hydraulic supply source. Fig. 8 is a diagram showing the state of entering a building.

[0038] An embodiment of the work vehicle of the present invention will be described with reference to the drawings. In the following description, the direction of the arrow FW shown in the drawings will be referred to as "forward," the direction of the arrow BK as "rearward," the direction of the arrow RH as "right," the direction of the arrow LH as "left," the direction of the arrow UP as "up," and the direction of the arrow DW as "down."

[0039] The work vehicle of this embodiment is equipped with a traveling device, an engine, an electric motor, and a battery that supplies power to the electric motor. The engine at least supplies power to the traveling device and charges the battery, and the electric motor supplies power to at least the traveling device. When traveling in an area where engine operation is restricted, the engine speed is set to below idling speed and the vehicle travels using power from the electric motor.

[0040] A specific configuration will be described below.

[0041] 1 to 3, the work vehicle is equipped with a vehicle body 1 that is generally rectangular in plan view and supports the entire vehicle, multiple hydraulically driven traveling devices B, and a hydraulically driven support mechanism A that supports the multiple traveling devices B on the vehicle body 1 so that they can each be raised and lowered. The traveling devices B are equipped with traveling wheels 2 that support the vehicle body 1, and a hydraulic motor 4 that drives the traveling wheels 2. In addition, multiple auxiliary wheels 3 are provided corresponding to the multiple traveling wheels 2, respectively.

[0042] The traveling wheels 2 are located at the front and rear of both the left and right sides of the vehicle body 1. In this embodiment, the work vehicle is equipped with four traveling wheels 2, located at the left front, right front, left rear, and right rear. Four support mechanisms A are provided, located at the left front, right front, left rear, and right rear, corresponding to the four traveling wheels 2. The support mechanism A includes a bending link mechanism 5 as a vehicle body support part, and a plurality of hydraulic cylinders 6, 7 that can individually change the position of the bending link mechanism 5. The four traveling wheels 2 are supported via the bending link mechanisms 5 so that they can be raised and lowered individually relative to the vehicle body 1.

[0043] The vehicle body 1 has a generally rectangular shape in a plan view, and is provided on the upper surface of the vehicle body 1 with a flat loading section 8 on which cargo can be loaded. The loading section 8 is formed in a generally rectangular shape in a plan view, and extends from the right end to the left end of the vehicle body 1. The loading section 8 is configured so that cargo can be placed on it. Examples of cargo that can be placed on the loading section 8 include agricultural machinery, agricultural materials such as fertilizer and chemicals, harvested crops and harvest baskets, and pallets on which these are placed.

[0044] The vehicle body 1 is provided, below the loading section 8, with a hydraulic supply source 9 that supplies hydraulic oil to the hydraulic equipment, and a control device C that controls the operation of each hydraulic equipment (hydraulic cylinders 6, 7, hydraulic motor 4, etc.) by adjusting the supply state of hydraulic oil from the hydraulic supply source 9. The control device C constitutes a switching mechanism, which will be described later.

[0045] 1 and 8, the hydraulic supply source 9 includes a hydraulic pump 10 as a hydraulic oil supply device that supplies hydraulic oil to the traveling device B and the support mechanism A, an electric motor M that drives the hydraulic pump 10, a battery T that supplies power to the electric motor M, a generator G that charges the battery T, and an engine E that drives the generator G. The engine E is an internal combustion engine that burns fuel to output rotational power, and emits exhaust gases during operation.

[0046] The electric motor M drives the hydraulic pump 10, and the hydraulic oil supplied from the hydraulic pump 10 is supplied to the traveling device B and the support mechanism A to drive them. Therefore, the electric motor M is configured to supply power to the traveling device B.

[0047] The control device C includes a hydraulic control mechanism 12 that adjusts the supply state of hydraulic oil from the hydraulic supply source 9, and an ECU (Electronic Control Unit) 13 that controls the operation of the hydraulic control mechanism 12. The ECU 13 includes a microcomputer and is capable of executing various controls according to a control program. The hydraulic control mechanism 12 includes a plurality of control valves (not shown) that individually supply and discharge hydraulic oil to and adjust the flow rate of each hydraulic device (hydraulic cylinders 6, 7, hydraulic motor 4, etc.).

[0048] [Support Mechanism] As shown in Figures 4 and 5, the articulating link mechanism 5 includes a base end portion 14 supported by the vehicle body 1, a first link 15 having an upper end portion supported on a lower portion of the base end portion 14 so as to be rotatable about a horizontal axis X1, and a second link 16 having one end portion supported on a lower end portion of the first link 15 so as to be rotatable about a horizontal axis X2 and having the other end portion supporting the running wheel 2.

[0049] A support bracket 17 that supports the traveling wheel 2 is supported by a boss portion 18 provided at the swing side end of the second link 16 so as to be swingable around the vertical axis Y. A hydraulic cylinder 20 (hereinafter referred to as a swing cylinder) for swing operation as a steering mechanism is provided across a bracket 19 on one end side of the second link 16 and an arm portion 17a provided on the support bracket 17.

[0050] A plurality of hydraulic cylinders 6, 7 are provided corresponding to the plurality of articulating link mechanisms 5, respectively, and capable of individually changing the posture of the articulating link mechanisms 5. That is, a first hydraulic cylinder 6 is provided that can change the swing posture of the first link 15 relative to the vehicle body 1, and a second hydraulic cylinder 7 is provided that can change the swing posture of the second link 16 relative to the first link 15.

[0051] When the first hydraulic cylinder 6 is extended or retracted with the operation of the second hydraulic cylinder 7 stopped, the first link 15, the second link 16, and the running wheel 2 swing together around the horizontal axis X1 of the pivotal connection point with respect to the base end 14, while maintaining a constant relative posture. When the second hydraulic cylinder 7 is extended or retracted with the operation of the first hydraulic cylinder 6 stopped, the second link 16 and the running wheel 2 swing together around the horizontal axis X2 of the connection point between the first link 15 and the second link 16, while maintaining a constant posture of the first link 15.

[0052] An auxiliary wheel 3 is rotatably supported at an intermediate bending portion of each of the plurality of bending link mechanisms 5. The auxiliary wheel 3 is configured as a wheel having a smaller diameter than the running wheel 2. A support shaft that pivotally connects the first link 15 and the second link 16 is formed to extend so as to protrude outward in the lateral width direction of the vehicle body, and the auxiliary wheel 3 is rotatably supported at the extended protruding portion of the support shaft.

[0053] By operating the turning cylinder 20, the traveling wheel 2 can be turned around the vertical axis Y relative to the articulating link mechanism 5, thereby allowing the vehicle to be turned.

[0054] By supplying and discharging hydraulic oil to the plurality of first hydraulic cylinders 6, the plurality of second hydraulic cylinders 7, and the turning cylinder 20, it is possible to change the position of each traveling wheel 2 relative to the vehicle body 1. In addition, by adjusting the flow rate of hydraulic oil corresponding to the hydraulic motor 4, it is possible to change the rotation speed of the hydraulic motor 4, i.e., the rotation speed of the traveling wheels 2.

[0055] [Sensors] This work vehicle is equipped with various sensors.

[0056] 6 , each of the four second hydraulic cylinders 7 is provided with a head-side pressure sensor S1 and a cap-side pressure sensor S2. The head-side pressure sensor S1 detects the internal pressure of the oil chamber in the head-side chamber of the second hydraulic cylinder 7. The cap-side pressure sensor S2 detects the internal pressure of the oil chamber in the cap-side chamber of the second hydraulic cylinder 7.

[0057] A plurality of stroke sensors S3 capable of detecting the amount of extension / contraction operation are provided for each of the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7. The amount of extension / contraction operation of each hydraulic cylinder 6, 7 is a detected value corresponding to the swing position of the first link 15 and second link 16 that are the objects of operation.

[0058] The vehicle body 1 is provided with an inclination sensor S4 that detects the inclination state of the vehicle body. The inclination sensor S4 is configured using an inertial measurement unit (IMU), which is a well-known configuration. The IMU has a three-axis acceleration sensor and a gyro sensor, and can detect changes in the attitude of the vehicle body 1, specifically, tilt in the front-rear and left-right directions.

[0059] A rotation sensor S5 is provided near the traveling wheels 2, which detects the rotation speed of the traveling wheels 2 driven by the hydraulic motor 4. Based on the rotation speed of the traveling wheels 2 detected by the rotation sensor S5, the supply of hydraulic oil to the hydraulic motor 4 is controlled so that the rotation speed of the traveling wheels 2 becomes a target value. A pressure sensor S6 is provided, which detects the pressure of the hydraulic oil supplied to the hydraulic motor 4. Based on the pressure of the hydraulic oil detected by the pressure sensor S6, the supply (pressure) of hydraulic oil to the hydraulic motor 4 is controlled so that the drive torque of the traveling wheels 2 becomes a target value. A stroke sensor S7 capable of detecting the extension / retraction operation amount is provided for each of the four swing cylinders 20.

[0060] A driving operation unit 21 is provided behind the loading section 8 of the vehicle body 1. The driving operation unit 21 can be manually operated by the driver from outside the vehicle. The vehicle can be driven by the driver operating the driving operation unit 21.

[0061] The driving operation unit 21 is provided with a so-called joystick-type control lever 29 that can be manually swung forward, backward, left, and right. By swung the control lever 29 forward, backward, left, and right from a neutral position (stopped state), the vehicle can be made to travel straight forward or backward, or turn in either the left or right direction. The driving operation unit 21 is also provided with other operating tools.

[0062] [Regarding Vehicle Control] The ECU 13 includes a non-volatile memory (not shown) that stores programs corresponding to the functional units described below, and a CPU (not shown) that executes the programs. The functions of each functional unit are realized by the CPU executing the programs. The ECU 13 includes, as functional units, an attitude control unit 100, a driving control unit 101, an engine control unit 102, and a charge state determination unit 103.

[0063] The attitude control unit 100 executes attitude control to control the attitude of the vehicle body to a desired state based on detection information from various sensors. The attitude control has a position control mode and a pressure control mode.

[0064] In the position control mode, the operation of the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7 is controlled based on the detection information from the tilt sensor S4 and the detection information from the stroke sensor S3 so that the loading section 8 of the vehicle body 1 is in a horizontal position. Specifically, the hydraulic control valves corresponding to the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7 are switched and controlled. As a result, even when traveling on a slope, the vehicle body 1 can maintain a substantially horizontal position, and can move without tipping over even when the loading section 8 is loaded with harvesting containers, equipment, etc.

[0065] In the pressure control mode, the hydraulic control valves can be switched to control the operation of the four second hydraulic cylinders 30 so that the thrust of the second hydraulic cylinders 30, calculated based on the detection values ​​of the head-side pressure sensor S1 and the cap-side pressure sensor S2, becomes a preset and stored target value. By controlling in this manner, the ground reaction force of the running wheels 2 is maintained at an appropriate value. As a result, the running wheels 2 move up and down while following the unevenness of the ground, and the running wheels 2 can smoothly travel on uneven terrain while maintaining an appropriate ground contact state and supporting the vehicle body 1 without spinning or being hindered.

[0066] The travel control unit 101 switches and controls the hydraulic control valves corresponding to the four swing cylinders 20 and the four hydraulic motors 4 based on the operating state of the control lever 29. When the control lever 29 is operated forward, the vehicle travels straight ahead, and when operated rearward, the vehicle travels straight ahead. When the control lever 29 is operated rightward, the vehicle turns to the right, and when operated leftward, the vehicle turns to the left.

[0067] Although not described in detail, the engine control unit 102 is configured to be able to start, stop, and adjust the rotation speed of the engine E. If charging of the battery T is required, the engine E can be operated to drive the generator G, thereby charging the battery T. The engine control unit 102 is configured to switch the charging state of the engine E, as will be described later.

[0068] (Regarding switching of charging state by engine) When the work vehicle according to the present invention travels in an area where the operation of the engine E is restricted, the rotation speed of the engine E is set to below idling rotation speed and the vehicle travels using power from the electric motor M. Specifically, when traveling in an area where the operation of the engine E is restricted, the rotation speed of the engine E is set to zero. The area where the operation of the engine E is restricted is indoors, and the area where the operation of the engine E is permitted is outdoors. Indoors means, for example, the inside of a greenhouse, and outdoors means the outside of the greenhouse.

[0069] The vehicle is further provided with a switching mechanism that can switch between a first state that permits operation of the engine E and a second state that restricts operation of the engine E. The switching mechanism switches to the first state when traveling outdoors and switches to the second state when traveling indoors. In this embodiment, the switching mechanism is configured by the control device C.

[0070] That is, the control device C is switchable between a first state that allows the operation of the engine E and a second state that restricts the operation of the engine E, and switches to the first state when traveling outdoors and switches to the second state when traveling indoors.

[0071] Specifically, the control state of the engine E by the engine control unit 102 of the ECU 13 can be switched between a first state in which the engine E operates to charge the battery T, and a second state in which the engine E is stopped and charging of the battery T is restricted. That is, in this embodiment, restricting the operation of the engine E means reducing the engine E's rotation speed to zero. The first state is set outdoors, and the second state is set indoors inside a greenhouse. As a result, when traveling outdoors, the engine E operates to charge the battery T, but when traveling inside the greenhouse, restricting charging of the battery T through the engine E prevents indoor air from being polluted by exhaust gases. The indoor location is not limited to the inside of a greenhouse, but may be the inside of another building, such as a large warehouse.

[0072] This work vehicle is provided with a switching command device 31 as switching command means that can be manually operated to switch the control device C between a first state and a second state. Also provided is a first display unit 33 as full charge notification means that notifies that the battery T is in a fully charged state, and when the full charge state is being notified, operating the switching command device 31 switches the control device C from the first state to the second state.

[0073] That is, it is equipped with a charge detection sensor 32 as a charge state detection means for detecting the charge state of the battery T, a charge state determination unit 103 for determining whether the battery T has reached a fully charged state based on the detection result of the charge detection sensor 32, and a first display unit 33 for notifying the operator by display information according to the determination result of the charge state determination unit 103.

[0074] The charge detection sensor 32 is a commonly used sensor with a well-known configuration, and its detection information is input to the control device C. A charge state determination unit 103 of the control device C determines whether the battery T is fully charged or not based on the detection information from the charge detection sensor 32 in accordance with a control program. The first display unit 33 is provided in the driving operation unit 21, and performs a display operation so that the operator operating the vehicle can visually confirm that the battery T is fully charged. At this time, in addition to the display operation by the first display unit 33, an audio notification such as a buzzer may also be performed.

[0075] The first display unit 33 may be displayed in a variety of ways. For example, it may be a lamp that lights up when the battery is not fully charged and turns off when the battery is not fully charged, or it may be displayed as an image. Alternatively, it may be an analog display such as a bar graph that shows the charge level, or an analog display in which different colored segments are arranged to show the charge level by changing the emitted color, and when the analog value exceeds a reference value, it indicates that the battery T is fully charged.

[0076] The switching command device 31 is provided in the driving operation unit 21 and is configured as a two-position switch. By manually switching the operating position, the control state of the engine E by the ECU 13 can be switched between a first state and a second state.

[0077] When the vehicle continues to travel outdoors, the switching command device 31 is switched to the first state, which allows the engine E to operate and charge the battery T. When the vehicle switches from traveling outdoors to traveling indoors, the operator confirms on the first display unit 33 that the battery is fully charged, and then switches the switching command device 31 to the second state.

[0078] The vehicle is provided with a second display unit 34 as a low-charge notification means for notifying the operator that the battery T has become undercharged due to use of the electric motor M. As shown in FIG. 2 , the second display unit 34 is provided to the side of the first display unit 33 in the driving operation unit 21. The second display unit 34 is used to notify the operator that the battery T has become undercharged in a manner that is recognizable to the operator. The various display modes mentioned for the fully charged state can be used as the display format. That is, when the charge state determination unit 103 determines that the battery T is undercharged based on the detection result of the charge detection sensor 32, the second display unit 34 notifies the operator of this.

[0079] If the battery T runs out of charge while traveling indoors, the vehicle will be unable to leave the building and will need to generate power using the engine. Therefore, when an insufficient charge state is to be notified, it is advisable to notify the vehicle when the battery T has sufficient charge to allow the vehicle to leave the building.

[0080] When working outdoors, automatic charging control may be performed by the engine control unit 102. That is, when the battery T is fully charged due to charging performed by the operation of the engine E, the engine control unit 102 may automatically stop the operation of the engine E, and when the battery T becomes undercharged, the engine control unit 102 may automatically start the engine E to begin charging. This may reduce unnecessary fuel consumption by the engine E.

[0081] Other Embodiments Other embodiments are listed below.

[0082] (1) In the above embodiment, the area in which the operation of engine E is restricted is indoors, and the area in which the operation of engine E is permitted is outdoors. However, instead of this, a part of the indoor area may be set as the area in which the operation of engine E is restricted, and another part of the indoor area may be set as the area in which the operation of engine E is permitted. Also, a part of the outdoor area may be set as the area in which the operation of engine E is restricted, and another part of the outdoor area may be set as the area in which the operation of engine E is permitted.

[0083] (2) In addition to the configuration of the above embodiment, or instead of the switching configuration using the switching command device 31, the following configuration may be used.

[0084] A charge state detection means for detecting the charge state of the battery T may be provided, and the control device C may be configured to switch to the second state when the charge state detection means detects that the battery T has reached a fully charged state. That is, when the battery T has reached a fully charged state based on the detection information of the charge detection sensor 32 in the above embodiment as the charge state detection means, the control device C (specifically, the ECU) may be configured to automatically switch from the first state to the second state.

[0085] (3) In addition to the configuration of the above embodiment, or instead of the switching configuration using the switching command device 31, the following configuration may be used.

[0086] A vehicle position determination means may be provided to determine whether the vehicle is outdoors or indoors, and the control device C may be configured to switch between a charging permitted state and a charging restricted state based on the determination result of the vehicle position determination means.

[0087] 8, for example, the control device C may be configured to include an open / closed state detection means (not shown) that detects whether door 201 (corresponding to the boundary between the indoors and outdoors) of building 200 is open or closed when the vehicle enters the indoors from the outdoors through door 201, and to switch from the charge-permitted state to the charge-restricted state at a location (corresponding to the restriction boundary) a predetermined distance before door 201 when the open / closed state detection means detects that door 201 is open. In this case, even when door 201 of building 200 is open, exhaust gas can be effectively prevented from entering the building by stopping operation of engine E a predetermined distance (e.g., several meters) before the open entrance of the building.

[0088] In other words, in this embodiment, the area in which the operation of engine E is restricted is the area inside the restricted boundary set indoors and a predetermined distance outside the boundary between indoors and outdoors, and the area in which the operation of engine E is permitted is the area outside the restricted boundary.

[0089] The vehicle position determination means may be, for example, a satellite positioning module that receives signals (including GPS signals) from a satellite positioning system such as GNSS (Global Navigation Satellite System) to acquire the vehicle's position, thereby making it possible to determine whether the vehicle is located inside (indoors) or outside (outdoors) of a building.

[0090] The open / closed state detection means may be configured to determine the presence or absence of an object (door) using, for example, an imaging device such as a camera, LiDAR (Light Detection And Ranging), or the like.

[0091] (4) In the above embodiment, when traveling in an area where engine operation is restricted, the operation of the engine E is restricted, i.e., the engine operation is stopped and the engine speed is set to zero. However, instead of this configuration, the speed of the engine E may be adjusted to be equal to or lower than the idling speed. In this case, the amount of exhaust gas generated by the engine cannot be reduced to zero, but it can be reduced to as low an amount as possible.

[0092] (5) In addition to the configuration of the above embodiment, or instead of the switching configuration using the switching command device 31, the following configuration may be used.

[0093] The vehicle may be provided with a posture determination means for determining whether the vehicle is in a tilted posture, and the control device C may be configured to switch to the first state if the vehicle is in a tilted posture based on the determination result of the posture determination means, and to switch to the second state if the vehicle is not in a tilted posture. The posture determination means is configured using an inclination sensor S4 provided on the vehicle body and a posture control unit 100.

[0094] (6) The support mechanism A may be a mechanism having one link or three or more links, and may be a mechanism having an electric actuator as a device for changing the posture of the support mechanism A.

[0095] (7) The electric motor M may be configured to be switchable between a state in which it supplies power to the traveling device B and the support mechanism A and a state in which the engine E supplies power to the traveling device B and the support mechanism A. In this case, when working indoors, the electric motor M switches to a state in which it supplies power to the traveling device B and the support mechanism A. Furthermore, the electric motor M and the engine E may be configured to be switchable to a state in which they cooperate to supply power to the traveling device B and the support mechanism A.

[0096] (8) Instead of the hydraulic cylinder 20 for the swing operation, a configuration may be adopted in which it is driven by a hydraulic motor, an electric motor, an engine, or the like.

[0097] The present invention can be applied to a work vehicle that is suitable for moving on slopes and uneven ground with bumps, for example.

[0098] 10 Hydraulic pump (hydraulic oil supply device) 31 Switching command device (switching command means) 32 Charge detection sensor (charging state detection means) 33 Full charge notification means 34 Insufficient charge notification means A Support mechanism B Traveling device C Control device (switching mechanism) E Engine G Generator M Electric motor T Battery

Claims

1. A work vehicle equipped with a traveling device, an engine, an electric motor, and a battery that supplies power to the electric motor, wherein the engine at least either supplies power to the traveling device or charges the battery, and the electric motor supplies power to at least the traveling device, and when traveling in an area where operation of the engine is restricted, the engine speed is kept below idling speed and the vehicle travels using power from the electric motor.

2. A work vehicle as set forth in claim 1, wherein the engine speed is set to zero when the work vehicle is traveling in an area where the engine operation is restricted.

3. A work vehicle as described in claim 1 or 2, wherein the area in which the operation of the engine is restricted is indoors or an area inside a restrictive boundary set a predetermined distance outside the indoors and the boundary between the indoors and outdoors, and the area in which the operation of the engine is permitted is outdoors or an area outside the restrictive boundary.

4. A work vehicle as described in claim 3, comprising a switching mechanism that can be switched between a first state that permits operation of the engine and a second state that restricts operation of the engine, the switching mechanism switching to the first state when traveling outdoors and switching to the second state when traveling indoors.

5. A work vehicle as set forth in claim 4, further comprising a switching command means for manually switching said switching mechanism between said first state and said second state.

6. A work vehicle as described in claim 5, further comprising: a charge state detection means for detecting the charge state of the battery; and a full charge notification means for notifying that the battery is fully charged; and when the full charge state is notified, the switching mechanism is switched from the first state to the second state by operating the switching command means.

7. A work vehicle as claimed in any one of claims 4 to 6, further comprising a charge state detection means for detecting the charge state of the battery, and the switching mechanism switches from the first state to the second state when it determines, based on information detected by the charge state detection means, that the battery has become fully charged as a result of charging caused by operation of the engine.

8. A work vehicle as described in any one of claims 4 to 7, further comprising a vehicle position discrimination means for discriminating whether the vehicle is outdoors or indoors, and the switching mechanism switches to the first state when the vehicle is outdoors and switches to the second state when the vehicle is indoors based on the discrimination result of the vehicle position discrimination means.

9. A work vehicle as described in any one of claims 4 to 8, further comprising an open / closed state detection means for detecting whether a door section is open or closed when the vehicle enters a building from outdoors through the door section, and the switching mechanism switches from the first state to the second state a predetermined distance before the door section when the open / closed state detection means detects that the door section is open.

10. A work vehicle as described in any one of claims 4 to 9, further comprising a posture discrimination means for discriminating whether the vehicle is in an inclined posture, and the switching mechanism switches to the first state if the vehicle is in an inclined posture based on the discrimination result of the posture discrimination means, and switches to the second state if the vehicle is not in an inclined posture.

11. A work vehicle as claimed in any one of claims 1 to 10, further comprising a charge shortage notification means for notifying the user that the battery has become insufficiently charged as a result of use of the electric motor.

12. A work vehicle as described in any one of claims 1 to 11, further comprising a support mechanism that supports a plurality of said traveling devices on the vehicle body so that each of said traveling devices can be raised and lowered separately, and said engine is capable of driving said traveling devices and said support mechanism in place of said electric motor or in cooperation with said electric motor.

13. A work vehicle as described in any one of claims 1 to 12, comprising a support mechanism that supports a plurality of traveling devices on the vehicle body so that each of the traveling devices can be raised and lowered separately, the plurality of traveling devices and the plurality of support mechanisms are configured to be hydraulically driven, a hydraulic oil supply device is provided that supplies hydraulic oil to the traveling devices and the support mechanisms, and the electric motor is configured to drive the hydraulic oil supply device.

Images