Work vehicles

Abstract

To provide work vehicles that are easy to operate and have improved maneuverability. [Solution] The work vehicle 10 comprises a body having a pair of rear wheels, a driver's seat 51, a rear differential lock device, and a rear differential lock operating unit 56. The rear differential lock device limits the differential movement of the pair of rear wheels. The rear differential lock operating unit 56 receives input for activating the rear differential lock device. The rear differential lock operating unit 56 is located in front of the driver's seat 51.

Description

Technical Field

[0001] The present invention relates to a work vehicle equipped with a driver's seat.

Background Art

[0002] As related art, a work vehicle such as a tractor is known which includes a pair of left and right front wheels (front wheels) as a running unit and a pair of left and right rear wheels (rear wheels) on a running body (see, for example, Patent Document 1). This work vehicle includes a differential gear mechanism for the rear wheels, and is configured such that the rotational power of the engine is transmitted to the left and right rear wheels via the differential gear mechanism for the rear wheels.

[0003] Here, the differential gear mechanism for the rear wheels has a rear differential lock device (differential lock mechanism) that stops its own differential (that is, drives the left and right rear wheels at the same speed). Below the driver's seat (operator's seat), a differential lock pedal for turning on / off the rear differential lock device is arranged. Therefore, the operator can operate the rear differential lock device by stepping on the differential lock pedal to stop the differential of the differential gear mechanism for the rear wheels and bring the left and right rear wheels into a state of being driven at the same speed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the configuration of the related art described above, since the differential lock pedal is at the operator's feet, some operators may find it difficult to visually recognize the differential lock pedal, and as a result, may feel that the operability of the work vehicle is low.

[0006] An object of the present invention is to provide a work vehicle that is easy to improve in operability. [Means for solving the problem]

[0007] A work vehicle according to one aspect of the present invention comprises a body having a pair of rear wheels, a driver's seat, a rear differential lock device, and a rear differential lock operating unit. The rear differential lock device limits the differential movement of the pair of rear wheels. The rear differential lock operating unit receives operations to activate the rear differential lock device. The rear differential lock operating unit is located in front of the driver's seat. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a work vehicle that is easy to operate. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic perspective view of the work vehicle according to Embodiment 1, seen from the left front. [Figure 2] Figure 2 is a schematic perspective view of the work vehicle according to Embodiment 1, seen from the left rear. [Figure 3] Figure 3 is a schematic plan view of the work vehicle according to Embodiment 1. [Figure 4] Figure 4 is a schematic left side view of the work vehicle according to Embodiment 1. [Figure 5] Figure 5 is a schematic right side view of the work vehicle according to Embodiment 1. [Figure 6] Figure 6 is a schematic front view of the work vehicle according to Embodiment 1. [Figure 7] Figure 7 is a schematic rear view of the work vehicle according to Embodiment 1. [Figure 8] Figure 8 is a block diagram showing the schematic configuration of a work vehicle according to Embodiment 1. [Figure 9] Figure 9 is a schematic plan view showing the interior of the cabin of the work vehicle according to Embodiment 1. [Figure 10] Figure 10 is a schematic perspective view showing the interior of the cabin of the work vehicle according to Embodiment 1. [Figure 11]FIG. 11 is a schematic right side view showing the operation section of the work vehicle according to Embodiment 1 with the cab omitted. [Figure 12] FIG. 12 is a schematic perspective view showing the inside of the cab of the work vehicle according to Embodiment 1. [Figure 13] FIG. 13 is a schematic view showing an example of the display of the display device of the work vehicle according to Embodiment 1. [Figure 14] FIG. 14 is a schematic perspective view showing the hydraulic cylinder of the work vehicle according to Embodiment 1. [Figure 15] FIG. 15 is a schematic plan view showing the structure related to the brake mechanism of the work vehicle according to Embodiment 1. [Figure 16] FIG. 16 is a schematic plan view showing the structure related to the brake mechanism of the work vehicle according to Embodiment 1. [Figure 17] FIG. 17 is a schematic perspective view showing the structure related to the brake mechanism of the work vehicle according to Embodiment 1. [Figure 18] FIG. 18 is a schematic left side view showing the structure related to the brake mechanism of the work vehicle according to Embodiment 1. [Figure 19] FIG. 19 is a schematic perspective view showing the structure related to the hydraulic pump of the work vehicle according to Embodiment 1. [Figure 20] FIG. 20 is a schematic right side view showing the structure related to the hydraulic pump of the work vehicle according to Embodiment 1. [Figure 21] FIG. 21 is a schematic right side view showing the structure related to the hydraulic pump of the work vehicle according to Embodiment 1. [Figure 22] FIG. 22 is a schematic right side view showing the structure related to the hydraulic pump of the work vehicle according to Embodiment 1. [Figure 23] FIG. 23 is a schematic cross-sectional view showing the structure related to the hydraulic pump of the work vehicle according to Embodiment 1. [Figure 24] FIG. 24 is a schematic perspective view showing the structure related to the hydraulic pump of the work vehicle according to Embodiment 1. [Figure 25] FIG. 25 is a schematic perspective view showing the structure related to the hydraulic pump of the work vehicle according to Embodiment 1. [Figure 26]Figure 26 is a schematic perspective view showing the area around the hood of the work vehicle according to Embodiment 1. [Figure 27] Figure 27 is a schematic perspective view showing the inside of the hood of the work vehicle according to Embodiment 1. [Figure 28] Figure 28 is a schematic perspective view showing the structure related to the cooling system of a work vehicle according to Embodiment 1. [Figure 29] Figure 29 is a schematic left side view showing the structure related to the cooling system of a work vehicle according to Embodiment 1. [Figure 30] Figure 30 is a schematic exploded perspective view showing the structure related to the cooling system of a work vehicle according to Embodiment 1. [Figure 31] Figure 31 is a schematic perspective view showing the structure related to the cooling system of a work vehicle according to Embodiment 1. [Figure 32] Figure 32 is a schematic front view showing the structure related to the cooling system of a work vehicle according to Embodiment 1. [Modes for carrying out the invention]

[0010] The embodiments of the present invention will be described below with reference to the attached drawings. The following embodiments are examples that embody the present invention and are not intended to limit the technical scope of the present invention.

[0011] (Embodiment 1) [1] Overall structure First, the overall configuration of the work vehicle 10 according to this embodiment will be described with reference to Figures 1 to 9.

[0012] The work vehicle 10 is equipped with a body 11. The body 11 is configured to be able to be fitted with a work implement 12 (see Figure 1). In Figure 1, the schematic outline of the work implement 12 is shown by dashed lines.

[0013] In this embodiment, for the sake of explanation, the vertical direction when the work vehicle 10 is in a usable state is defined as the up-down direction D1 (see Figure 1). The forward-backward direction D2 and left-right direction D3 are defined based on the direction as seen from the operator (driver) sitting in the machine body 11 (driver's unit 5) of the work vehicle 10. The left side of the left-right direction D3 refers to the left side when the machine body 11 is traveling forward (moving forward), and the right side of the left-right direction D3 refers to the right side when the machine body 11 is traveling forward (moving forward). However, these directions are not intended to limit the direction of use (direction during use) of the work vehicle 10.

[0014] The work vehicle 10 moves through the target area F1 (see Figure 1) and performs some work within the target area F1 using the work implement 12. In this disclosure, "work" refers to the work performed by the work implement 12 on the target area F1, and includes various agricultural operations such as tilling, leveling, sowing, fertilizing, pesticide spraying, planting (rice planting), or harvesting, as well as various construction operations. In this embodiment, as an example, the work performed by the work vehicle 10 is tilling.

[0015] The implement 12 performs work within the target area F1 as the body 11 of the work vehicle 10 moves through the target area F1. In this embodiment, as an example, the implement 12 is a tiller such as a rotary tiller or plow that performs tilling work.

[0016] This type of implement 12 includes a directly mounted implement that is directly attached to a three-point linkage, and a towed implement that is towed by the machine body 11. In this embodiment, as an example, the implement 12 is a directly mounted rotary tiller that is detachably attached to the machine body 11 of the work vehicle 10. Here, the implement 12 is attached to the rear side of the machine body 11 (opposite the direction of forward movement of the machine body 11). In other words, the (directly mounted) implement 12 is connected to the rear side of the machine body 11 and performs work while moving forward with the machine body 11 when the machine body 11 moves forward. In this embodiment, the implement 12 is included as a component of the work vehicle 10, but since the implement 12 is detachable from the machine body 11, it does not have to be included as a component of the work vehicle 10.

[0017] In this disclosure, "work vehicle" means a vehicle that performs various tasks in a target area F1 such as a field, and as an example, agricultural machinery such as a tractor, seeder, rice transplanter, sprayer, sprayer, transplanter, and harvester. The work vehicle 10 may also be, for example, construction machinery. In this embodiment, unless otherwise specified, the explanation will be given using the example of a tractor equipped with a rotary tiller as the implement 12 as the work vehicle 10. In other words, the work vehicle 10 is constructed by connecting a (directly mounted) rotary tiller as the implement 12 to a tractor as the machine body 11. With this work vehicle 10, tilling work in the target area F1 such as a field becomes possible as the machine body 11 travels over the target area F1.

[0018] Thus, in this embodiment, the machine 11 is a type of vehicle that moves by traveling through a target area F1. Here, the machine 11 is equipped with a pair of front wheels 111 as steering wheels and a pair of rear wheels 112 as drive wheels, and travels through the target area F1 using these four wheels (the pair of front wheels 111 and the pair of rear wheels 112).

[0019] In this disclosure, the "target area" refers to an area in which the work vehicle 10 performs various operations such as tilling, leveling, sowing, fertilizing, pesticide spraying, planting (rice planting), or harvesting while moving, and includes paddy fields, dry fields, orchards, and pastures. For example, if the target area F1 is a paddy field or dry field where crops (agricultural products) such as rice, wheat, soybeans, or buckwheat are grown, the crops grown in the target area F1 are agricultural products. Furthermore, if trees are grown in a nursery, the nursery becomes the target area F1, and if trees that will become timber are grown in a forest, as in forestry, the forest becomes the target area F1. In this case, the crops grown in the target area F1 are trees or shrubs. In this embodiment, unless otherwise specified, the work vehicle 10 is used for tilling work in a field (target area F1), and the explanation will be given using the example that the target area F1 is a paddy field for growing rice. Furthermore, the target area F1 is not limited to fields; for example, if the work vehicle 10 is a construction machine, then the site where the construction machine performs its work becomes the target area F1.

[0020] Furthermore, the work vehicle 10 can travel not only within the target area F1 (in this case, the field) but also on roads outside the target area F1, such as off-field routes. Off-field routes are, for example, inter-field connecting roads that connect multiple target areas F1 (fields). Inter-field connecting roads may be farm roads, forest roads, public roads, private roads, or expressways, and may be roads exclusively for the work vehicle 10 or roads that are accessible to general vehicles (passenger cars, etc.).

[0021] In the work vehicle 10 according to this embodiment, the machine body 11 has a driver's seat 51 (see Figure 9). The driver's seat 51 is where the operator (driver) sits. Therefore, the work vehicle 10 performs work while traveling through the target area F1 by operation (manual driving) by the operator sitting in the driver's seat 51.

[0022] However, the work vehicle 10 is not limited to being driven by an operator sitting in the driver's seat 51 (manual driving), but may also be capable of operating by automatic driving (autonomous driving, etc.). Furthermore, the work vehicle 10 may be an unmanned vehicle that drives automatically, or it may be operated by remote control of an operator.

[0023] In this disclosure, "autonomous driving" includes "autonomous driving," in which the work vehicle 10 drives autonomously without operator intervention, and "semi-autonomous driving," in which only steering is automated, such as in straight-line assist. "Autonomous driving" is a driving mode in which, for example, the front wheels 111 are automatically steered and vehicle speed and other controls are also automatically performed so that the work vehicle 10 drives along a target path. "Straight-line assist" is a driving mode in which, for example, the front wheels 111 are automatically steered, and vehicle speed and other controls are performed by the operator, so that the work vehicle 10 drives along a straight path parallel to a reference straight line (reference line).

[0024] In other words, "semi-autonomous driving" means that the work vehicle 10 cannot move without operator intervention, but the burden of steering is reduced for the operator, and it is possible to drive along a target path such as a straight line, leading to improved work efficiency. Furthermore, in both autonomous driving and semi-autonomous driving, the front wheels 111 are automatically steered, so it can be said to be a form of "automatic steering mode". In automatic steering mode, the front wheels 111 are automatically steered by an automatic steering mechanism including a steering motor. That is, instead of the operator operating the steering wheel 52 (see Figure 9), automatic steering is achieved by changing the direction of the front wheels 111 with the output of the steering motor.

[0025] The work vehicle 10 includes a driver's unit 5, a power source 6, and a body 11 having four wheels (front wheels 111 and rear wheels 112), as well as a running gear 13, steering gear 14, braking mechanism 15, hydraulic pump 16, lifting device 17, cooling device 18, and display device 19, as shown in Figure 8. The work vehicle 10 further includes a control device 2, a first display unit 31, a second display unit 32, a notification unit 33, and a restricted status display unit 34.

[0026] The driver's seat 51 is located in the driver's compartment 5, along with a steering wheel 52, control levers 54 (see Figure 9), and pedals 55 (see Figure 9). The steering wheel 52, control levers 54, and pedals 55 are controls operated by the operator seated in the driver's compartment 5. The work vehicle 10 is configured to be manually driven by the operator manually operating these controls.

[0027] The types of driver's units 5 for the work vehicle 10 include cabin type, canopy type, and lops type. The cabin type driver's unit 5 is equipped with a cabin 50, and the driver's seat 51 is located in the interior space of the cabin 50. The canopy type driver's unit 5 is equipped with a canopy (roof), and the driver's seat 51 is located in the space below the canopy. The lops type driver's unit 5 is not equipped with a cabin 50 or canopy, and the driver's seat 51 is located in an open space above. In this embodiment, the case in which the driver's unit 5 is equipped with a cabin type is described as an example.

[0028] The cabin 50 has a door that can be opened and closed on at least one side in the left-right direction D3. The operator can enter and exit the driver's compartment 5 through this door. The cabin 50 has glass panels on its front, rear (back), left side, and right side.

[0029] A work implement coupling section 113 (see Figure 2), which consists of a three-point linkage mechanism, is provided at the rear of the machine body 11. A work implement 12 can be attached to the work implement coupling section 113. Power generated by the power source 6 can be transmitted to the towed work implement 12 via the transmission and the power take-off shaft (PTO shaft) located at the rear of the machine body 11. Here, since the work implement 12 is detachably connected to the work implement coupling section 113, it is also possible to connect a device other than the work implement 12 to the machine body 11.

[0030] In this embodiment, the implement 12 is a directly mounted rotary tiller, so tilling can be performed on the field, which is the target area F1, when the machine body 11 is moving forward. The implement 12 has a variable relative position (relative height) in the vertical direction D1 with respect to the machine body 11. As a result, the height of the implement 12 is variable when the field surface, which is the ground surface of the target area F1, is used as a reference. For example, by raising the implement 12 to a height away from the ground surface of the target area F1, the work vehicle 10 can also travel in a non-working state without performing work with the implement 12.

[0031] The lifting device 17 is a device that performs the lifting and lowering operation of the work machine 12. The lifting and lowering operation of the work machine 12 is an operation that changes the relative position (relative height) of the work machine 12 in the vertical direction D1 with respect to the machine body 11. In other words, the lifting device 17 lifts and lowers (raises or lowers) the work machine 12 between the lower limit position and the upper limit position, moving the work machine 12 to an arbitrary height from the ground surface of the target area F1.

[0032] The running gear 13 is a device that drives the work vehicle 10 by driving the rear wheels 112 (a pair of left and right drive wheels). The running gear 13 includes a transmission and transmits the power generated by the power source 6 to the rear wheels 112 via the transmission, thereby moving the machine body 11 forward or backward. In this embodiment, the rear wheels 112 are ordinary wheels, but it is not limited to this, and for example, the machine body 11 may be a half-crawler type with crawler tracks (tracks) on the rear wheels 112.

[0033] The steering device 14 is a device that steers the front wheels 111, which are a pair of steering wheels. The steering device 14 includes a steering wheel 52 and steers the front wheels 111 in response to the operator's input to the steering wheel 52. As shown in Figure 3, the pair of front wheels 111 have a reference posture in a plan view where they are facing in the longitudinal direction D2, that is, with their axis of rotation aligned with the lateral direction D3, and the steering device 14 steers them so that they tilt to the left or right from the reference posture. In other words, the steering device 14 steers the front wheels 111 by changing the orientation of the pair of front wheels 111.

[0034] When the steering 52 is operated clockwise from the position of the pair of front wheels 111, the steering device 14 steers the pair of front wheels 111 (front ends) to the right, causing the aircraft 11 to turn to the right when moving forward. On the other hand, when the steering 52 is operated counterclockwise from the position of the pair of front wheels 111, the steering device 14 steers the pair of front wheels 111 (front ends) to the left, causing the aircraft 11 to turn to the left when moving forward. In this embodiment, the operator operates the steering 52 during manual steering, but it is not limited to this, and manual steering may be performed by the operator operating, for example, an operating lever.

[0035] With the running gear 13 and steering gear 14, the aircraft 11 can move within the target area F1 in the longitudinal direction D2 and the lateral direction D3. For example, when the aircraft 11 is moving forward due to the rear wheels 112 being driven by the running gear 13, if the angle of the front wheels 111 is changed by the steering gear 14, the aircraft 11 will turn in the lateral direction D3, changing the direction of travel of the aircraft 11.

[0036] The braking mechanism 15 slows down or stops the machine 11. The braking mechanism 15 applies brakes to a pair of braking wheels (rear wheels 112) through two systems: operation of the brake pedal and automatic control. In other words, the braking mechanism 15 slows down or stops the machine 11 while it is moving by braking the rear wheels 112, which act as a pair of braking wheels.

[0037] An example of automatic control of the braking mechanism 15 is an "auto brake" that, when the steering angle of the steering 52 exceeds a predetermined angle, activates the braking mechanism 15 on the inner rear wheel 112 during a turn. With such an auto brake, the work vehicle 10 can keep the turning radius small, making it easier to perform tight turns, such as a U-turn (for example, changing direction at the headland of the target area F1).

[0038] The power source 6 is a drive source that supplies power to at least the running gear 13. The power source 6 is located at the front of the machine body 11, covered by a bonnet 114. The power source 6 is the drive source for the work vehicle 10, and is, for example, a diesel engine. However, the power source 6 of the work vehicle 10 is not limited to a diesel engine, but may be an engine such as a gasoline engine, an electric motor, or a hybrid system of an engine and an electric motor.

[0039] The power source 6 drives the hydraulic pump 16. In other words, the hydraulic pump 16 is driven by power transmitted from the power source 6 via a power transmission mechanism. The hydraulic pump 16 supplies hydraulic fluid to various hydraulic devices (hydraulic cylinders, hydraulic clutches, etc.) to operate the hydraulic devices.

[0040] The driver's unit 5 is located behind the power source 6 in the aircraft body 11. The driver's unit 5 includes a driver's seat 51 and a dashboard 53 (see Figure 9), etc. The dashboard 53 also serves as the steering column and is located in front of the driver's seat 51.

[0041] The steering wheel 52 is, for example, a steering wheel operated by an operator sitting in the driver's seat 51. The steering wheel 52 is rotatably supported by a steering shaft located within the dashboard 53. The steering wheel 52 is located in front of the driver's seat 51 and above the dashboard 53. The steering device 14 can change the direction (steering angle) of the front wheels 111 by rotating the steering wheel 52.

[0042] In addition, the driver's unit 5 is equipped with, for example, an operating lever 54 and pedals 55 operated by the operator, and a meter that indicates the speed of the work vehicle 10. The operating lever 54 may include multiple types of levers, such as a main gear lever, a sub-gear lever, or a work lever. The pedals 55 may also include multiple types of pedals, such as an accelerator pedal and a brake pedal.

[0043] Furthermore, the work vehicle 10 is equipped with a transmission case 115, as shown in Figures 4 and 5. The transmission case 115 has a power transmission mechanism that transmits power from the power source 6. The transmission case 115 includes at least a clutch housing and is located below the driver's unit 5 (cabin 50).

[0044] The cooling system 18 is a device that cools at least the power source 6, etc. Like the power source 6, the cooling system 18 is located at the front of the aircraft body 11, covered by the bonnet 114. The cooling system 18 includes a radiator 61 (see Figure 27).

[0045] The display device 19 is located in the operation unit 5 and is a user interface for presenting information to the operator, such as a liquid crystal display or an organic EL display that displays various types of information. The display device 19 presents various types of information to the operator by display. In this embodiment, as an example, the display device 19 is a full-color liquid crystal display with a backlight and has a horizontally elongated display area.

[0046] Furthermore, the display device 19 accepts various operations from the operator by outputting electrical signals corresponding to the user's (operator's) actions. This allows the user operator to view the display screen shown on the display device 19 and operate the display device 19 as needed.

[0047] The control device 2 controls various parts of the work vehicle 10. The control device 2 is configured to communicate with devices installed on various parts of the machine body 11. Here, the control device 2 may exchange various types of information (data) directly with each device, or it may do so indirectly via a relay or the like.

[0048] The control device 2 primarily consists of a computer system having one or more processors such as a CPU (Central Processing Unit) and one or more memories such as ROM (Read Only Memory) and RAM (Random Access Memory), and performs various processes (information processing). In this embodiment, the control device 2 is an integrated controller that controls the entire work vehicle 10, and consists of, for example, an electronic control unit (ECU). However, the control device 2 may be provided separately from the integrated controller.

[0049] As shown in Figure 8, the control device 2 includes an acquisition processing unit 21, a differential lock control unit 22, and a regulation control unit 23. In this embodiment, as an example, the control device 2 mainly consists of a computer system having one or more processors, so these multiple functional units (acquisition processing unit 21, etc.) are realized by one or more processors executing a control program. These multiple functional units included in the control device 2 may be distributed and provided in multiple housings, or they may be provided in a single housing.

[0050] The acquisition processing unit 21 executes an acquisition process to acquire information regarding the status of each part of the work vehicle 10 (including information regarding the operating status of the control devices and information regarding the detection results of sensors for monitoring the operating status of the machine body 11).

[0051] The differential lock control unit 22 performs differential lock processing to control the rear differential lock device 131 (see Figure 7) and the front differential lock device 132 (see Figure 6), which will be described later.

[0052] The control unit 23 executes a lifting restriction process to restrict the operation of the lifting device 17.

[0053] The first display unit 31, the second display unit 32, the notification unit 33, and the regulatory status display unit 34 each provide a display (or notification). The forms of "display (or notification)" here include, for example, display on the display device 19, other displays (including turning on / off indicator lights), sound (including voice) output, vibration, or transmission to other terminals. Details of the first display unit 31, the second display unit 32, the notification unit 33, and the regulatory status display unit 34 will be described later.

[0054] In addition to the above-described configuration, the work vehicle 10 is further equipped with a battery, fuel tank, and various sensors. The battery supplies power for operation to various parts of the work vehicle 10, such as the control device 2.

[0055] [2] Configuration related to differential lock function Next, the configuration related to the differential lock function of the work vehicle 10 according to this embodiment will be described in detail with reference to Figures 9 to 11.

[0056] First, the work vehicle 10 according to this embodiment is equipped with a differential gear to achieve "differential" rotation between the left and right wheels for at least one pair of rear wheels 112. Specifically, the transmission case 115 contains a hydraulic continuously variable transmission, a forward / reverse switching mechanism, and a drive transmission gear mechanism, as well as a differential gear mechanism for the rear wheels. Power (rotational power) from the power source 6 is transmitted to the input shaft of the transmission case 115, and is appropriately shifted by the hydraulic continuously variable transmission and the drive transmission gear mechanism. This shifted power is then transmitted to the pair of rear wheels 112 via the differential gear mechanism for the rear wheels.

[0057] Here, the rear differential gear mechanism is provided with a rear differential lock device 131 that limits (prohibits) the differential of a pair of rear wheels 112, causing the pair of rear wheels 112 to rotate at a constant speed. The rear differential lock device 131 limits the differential by mechanically connecting the left and right axles connected to the pair of rear wheels 112, thereby eliminating the rotational difference. For example, the rear differential lock device 131 has a differential lock body, and by engaging the differential lock body with the differential gear case, the differential gear case is fixed to one of the differential output shafts on the left or right side, and the differential function of the rear differential gear mechanism is stopped. When the rear differential lock device 131 is activated, the rear differential gear mechanism enters a "differential lock state," and the pair of rear wheels 112 rotate at a constant speed without rotational difference.

[0058] The rear differential lock device 131 restricts the differential action of the pair of rear wheels 112 in specific situations, such as when driving through mud or during plowing. In other words, in situations where the differential gear causes one of the pair of rear wheels 112 to slip, making it impossible to move forward or maintain a straight line, the rear differential lock device 131 activates to restrict the differential action of the pair of rear wheels 112, thereby improving off-road capability. However, if the differential action of the pair of rear wheels 112 is restricted in situations where it is not necessary, steering ability may decrease, potentially hindering the movement of the work vehicle 10.

[0059] Therefore, the state in which the rear differential lock device 131 is activated (the state in which the rear differential lock device 131 is "enabled") and the state in which the rear differential lock device 131 is not activated (the state in which the rear differential lock device 131 is "disabled") can be switched according to the operator's actions.

[0060] Incidentally, in the work vehicle 10 according to this embodiment, the rear differential lock operating unit 56 for switching the rear differential lock device 131 on or off is located in front of the driver's seat 51 inside the cabin 50, as shown in Figures 9 and 10. That is, the work vehicle 10 comprises a body 11 having a pair of rear wheels 112, a driver's seat 51, a rear differential lock device 131, and a rear differential lock operating unit 56. The rear differential lock device 131 limits the differential movement of the pair of rear wheels 112. The rear differential lock operating unit 56 receives operations to activate the rear differential lock device 131. Here, the rear differential lock operating unit 56 is located in front of the driver's seat 51.

[0061] With this configuration, the rear differential lock control unit 56 is positioned in a location that is easily visible and easy to operate for the operator sitting in the driver's seat 51. Therefore, compared to, for example, a differential lock pedal for switching the rear differential lock device 131 on or off being located at the operator's feet, the operator can more easily see the rear differential lock control unit 56. As a result, there is an advantage in that the operability of the work vehicle 10 can be easily improved.

[0062] Furthermore, the work vehicle 10 according to this embodiment is equipped with a differential gear mechanism for the front wheels, similar to the rear wheels 112, to achieve "differential" rotation between the left and right wheels. The work vehicle 10 further includes a front differential lock device 132 and a front differential lock operating unit 57. The front differential lock device 132 limits the differential rotation of the pair of front wheels 111 of the machine body 11. The front differential lock operating unit 57 receives operations to activate the front differential lock device 132.

[0063] As a result, similar to the pair of rear wheels 112, the front differential lock device 132 can be activated in certain situations to limit the differential movement of the pair of front wheels 111, thereby improving off-road capability.

[0064] Here, the front differential lock operating unit 57 for switching the front differential lock device 132 on or off is located adjacent to the rear differential lock operating unit 56, as shown in Figure 10. In other words, the rear differential lock operating unit 56 and the front differential lock operating unit 57 are located side by side in front of the driver's seat 51. In this embodiment, as an example, the rear differential lock operating unit 56 and the front differential lock operating unit 57 are arranged side by side in the vertical direction D1 such that the rear differential lock operating unit 56 is located below.

[0065] As a result, the front differential lock control unit 57 is positioned in a location that is easily visible and easy to operate for the operator sitting in the driver's seat 51. Therefore, compared to, for example, a differential lock pedal for switching the front differential lock device 132 on or off being located at the operator's feet, the operator can more easily see the front differential lock control unit 57. Consequently, there is an advantage in that the operability of the work vehicle 10 can be easily improved.

[0066] More specifically, both the rear differential lock operating unit 56 and the front differential lock operating unit 57 consist of momentary push-button switches. When the rear differential lock device 131 is disabled (not in operation) and the rear differential lock operating unit 56 is pressed while the rear activation conditions are met, the differential lock control unit 22 of the control device 2 activates (operates) the rear differential lock device 131. Similarly, when the front differential lock device 132 is disabled (not in operation) and the front differential lock operating unit 57 is pressed while the front activation conditions are met, the differential lock control unit 22 activates (operates) the front differential lock device 132.

[0067] Conversely, when the rear differential lock device 131 is enabled (operating) and the rear differential lock operating unit 56 is pressed, the differential lock control unit 22 disables (deactivates) the rear differential lock device 131. Similarly, when the front differential lock device 132 is enabled (operating) and the front differential lock operating unit 57 is pressed, the differential lock control unit 22 disables (deactivates) the front differential lock device 132.

[0068] Here, the activation conditions (rear activation conditions and front activation conditions) for operating the differential lock devices (rear differential lock device 131 and front differential lock device 132) include various conditions. As an example, the activation conditions include at least one of the following: the steering angle of the steering 52 is less than or equal to a predetermined angle, the vehicle speed is less than or equal to a predetermined value, the auxiliary transmission is in a low gear, and one brake is off.

[0069] In this context, "single-sided braking" refers to a state where the brakes on a pair of rear wheels 112 act independently on the left and right sides. In other words, as shown in Figure 10, the work vehicle 10 is equipped with a pair of brake pedals 581 and 582 arranged in a left-right direction D3 at the lower front of the driver's seat 51. The braking mechanism 15 applies the brake to the left rear wheel 112 in response to the depression of the left brake pedal 581, and applies the brake to the right rear wheel 112 in response to the depression of the right brake pedal 582. When single-sided braking is on (enabled), for example, when the machine 11 is turning, it is possible to reduce the turning radius by applying the brake only to the rear wheel 112 on the inside of the turn. On the other hand, in situations where the vehicle is traveling at relatively high speeds, such as on a road, in order to avoid sharp turns, for example, the pair of brake pedals 581 and 582 are connected by a brake connector 583, and single-sided braking is turned off (disabled).

[0070] In short, in this embodiment, the brake mechanism 15 includes a pair of brake devices that brake each of the pair of rear wheels 112. The rear differential lock device 131 is activated when the rear differential lock operating unit 56 is operated while the (rear) activation conditions are met. The (rear) activation conditions include the pair of brake devices being in a brake-linked state in which they are linked. In other words, the brake connector 583 connects the pair of brake pedals 581 and 582, and the pair of brake devices are in a brake-linked state in which they are linked; in other words, one brake is off (inactive) is included as an activation condition for the rear differential lock device 131 to operate.

[0071] This allows the rear differential lock device 131 to be activated only when one brake, which is intended to create a rotational difference between the pair of rear wheels 112, is off, thereby limiting the differential between the pair of rear wheels 112. Therefore, it is possible to avoid a situation where only one of the pair of rear wheels 112 is braked while the differential between the pair of rear wheels 112 is limited.

[0072] Furthermore, in this embodiment, the rear differential lock device 131 is activated when the rear differential lock operating unit 56 is operated while the rear activation conditions are met, and the front differential lock device 132 is activated when the front differential lock operating unit 57 is operated while the front activation conditions are met. Here, the rear activation conditions and the front activation conditions can be set individually. In other words, the activation conditions for activating the differential lock devices can be set individually for the rear differential lock device 131 and the front differential lock device 132, respectively.

[0073] This allows for settings such as including the condition that one brake is off (disabled) as an activation condition (for the rear) for the rear differential lock device 131 to operate, but not as an activation condition (for the front) for the front differential lock device 132 to operate. Consequently, the operability of the work vehicle 10 is further improved.

[0074] The work vehicle 10 according to this embodiment is equipped with a dashboard 53 located in front of the driver's seat 51. The rear differential lock operating unit 56 (and the front differential lock operating unit 57) are located on the dashboard 53. Other switches and meters are located on the dashboard 53.

[0075] With this configuration, the operator sitting in the driver's seat 51 can more easily reach the rear differential lock operating unit 56 (and the front differential lock operating unit 57), improving the operability of the rear differential lock operating unit 56 (and the front differential lock operating unit 57).

[0076] In this embodiment, the rear differential lock operating unit 56 and the front differential lock operating unit 57 are positioned to the right of the center of the left-right direction D3 on the dashboard 53, lower than the steering wheel 52, and in front of the steering wheel 52.

[0077] More specifically, as shown in Figure 11, in a side view, the rear differential lock operating section 56 (and the front differential lock operating section 57) is positioned in front of the front end of the steering wheel 52. Furthermore, in a side view, the rear differential lock operating section 56 (and the front differential lock operating section 57) is positioned lower than the lower end of the steering wheel 52.

[0078] Furthermore, the steering wheel 52 may have a variable vertical position (height) D1 by a tilt mechanism and / or telescopic mechanism. As an example, let's assume that the steering wheel 52 is positioned at the position shown by the dashed line (double-dotted line) in Figure 11 by moving to the lower end of its range of motion. In this case, the rear differential lock operating unit 56 (and the front differential lock operating unit 57) will be at the same height as the steering wheel 52. In other words, the work vehicle 10 is equipped with a steering wheel 52 located in front of the driver's seat 51, and in a side view, the rear differential lock operating unit 56 (and the front differential lock operating unit 57) is positioned higher than the lower end of the steering wheel 52.

[0079] With this configuration, from the perspective of the operator sitting in the driver's seat 51, the rear differential lock operating section 56 and the front differential lock operating section 57 are more easily visible through the gaps in the spokes of the steering wheel 52, as shown in Figure 10.

[0080] Furthermore, as shown in the speech bubble in Figure 10, the work vehicle 10 according to this embodiment is positioned to correspond to the rear differential lock operating unit 56 and is equipped with an indicator mark M1 that represents the function of the rear differential lock operating unit 56. The indicator mark M1 is an icon representing the rear differential lock and is affixed to the operating surface (surface) of the push-button switch that serves as the rear differential lock operating unit 56. The indicator mark M1 is affixed to the rear differential lock operating unit 56 itself or in its vicinity in the form of printing, engraving, or a sticker.

[0081] This makes it easier for the operator to understand that operating the rear differential lock control unit 56 activates the rear differential lock device 131, thereby improving the operability of the work vehicle 10.

[0082] In this embodiment, the work vehicle 10 is positioned to correspond to the front differential lock operating unit 57 and further includes an indicator mark M2 representing the function of the front differential lock operating unit 57. The indicator mark M2 is an icon representing the front differential lock and is attached to the operating surface of the push-button switch representing the front differential lock operating unit 57. The indicator mark M2 is attached to the front differential lock operating unit 57 itself or in its vicinity by means of printing, engraving, or a sticker.

[0083] Incidentally, at least when the activation conditions are met, the rear differential lock device 131 is switched between enabled and disabled each time the rear differential lock operating unit 56 is operated. Therefore, the operator needs to understand the current operating status (enabled / disabled) of the rear differential lock device 131 before operating the rear differential lock operating unit 56.

[0084] Therefore, the first display unit 31 displays the operating status of the rear differential lock device 131. The first display unit 31 is controlled by the differential lock control unit 22 of the control device 2, and the content (display mode) of the display changes depending on the operating status of the rear differential lock device 131. In this embodiment, as an example, the first display unit 31 includes a light-emitting unit built into the push-button switch which serves as the rear differential lock operation unit 56, and the operating status of the rear differential lock device 131 is displayed by the state of its illumination (on, off, or blinking, etc.). For example, when the operator operates the rear differential lock operation unit 56 and the rear differential lock device 131 is activated (operated), the light-emitting unit which serves as the first display unit 31 lights up.

[0085] This allows the operator to understand the current operating status (enabled / disabled) of the rear differential lock device 131 via the first display unit 31. In particular, as in this embodiment, the operating status of the rear differential lock device 131 is indicated by the illumination state of the push-button switch itself, which serves as the rear differential lock operation unit 56, making it easier for the operator to understand the operating status of the rear differential lock device 131.

[0086] Furthermore, as described above in this embodiment, the rear differential lock device 131 is activated when the rear differential lock operation unit 56 is operated while the (rear) activation conditions are met. Therefore, the second display unit 32 indicates whether or not the (rear) activation conditions are met. The second display unit 32 is controlled by the differential lock control unit 22 of the control device 2, and the display content (display mode) changes depending on whether or not the (rear) activation conditions are met. In this embodiment, as an example, the second display unit 32 includes a light-emitting unit built into the push-button switch which serves as the rear differential lock operation unit 56, and the display content (display mode) changes depending on whether or not the (rear) activation conditions are met, based on the state of its illumination (e.g., the color of the illumination). For example, the light-emitting unit as the second display unit 32 emits light in green when the (rear) activation conditions are met, and emits light in yellow when the (rear) activation conditions are not met.

[0087] This allows the operator to determine, via the second indicator unit 32, whether or not the rear differential lock device 131 can be activated by operating the rear differential lock operating unit 56. In particular, as in this embodiment, the illumination state of the push-button switch itself, which serves as the rear differential lock operating unit 56, indicates whether or not the activation conditions are met, making it easier for the operator to understand whether or not the activation conditions are met. Furthermore, by providing three or more illumination states (e.g., illumination color) for the illumination unit, it is possible to use a single illumination unit for both the first indicator unit 31 and the second indicator unit 32. For example, when the rear differential lock device 131 is disabled, the illumination unit illuminates yellow if the (rear) activation conditions are not met, green if the (rear) activation conditions are met, and red when the rear differential lock device 131 is activated.

[0088] Furthermore, the rear differential lock device 131 is activated when the rear differential lock operating unit 56 is operated while the (rear) activation conditions are met. Here, the notification unit 33 provides notification when the rear differential lock operating unit 56 is operated while the (rear) activation conditions are not met. The notification unit 33 is controlled by the differential lock control unit 22 of the control device 2 and provides notification when the rear differential lock operating unit 56 is operated while the (rear) activation conditions are not met. In this embodiment, as an example, the notification unit 33 provides notification by displaying on the display device 19. For example, if the rear differential lock operating unit 56 is operated while the (rear) activation conditions are not met, the notification unit 33 displays a pop-up message on the display device 19 indicating that the activation conditions are not met.

[0089] This allows the operator to understand that if the rear differential lock device 131 does not activate despite operating the rear differential lock operating unit 56, it is because the activation conditions are not met, and therefore the rear differential lock device 131 does not activate.

[0090] Furthermore, the front differential lock device 132 may also be provided with at least one of the first display unit 31, the second display unit 32, and the notification unit 33, similar to the rear differential lock device 131. For example, if the first display unit 31 is provided with respect to the front differential lock device 132, the first display unit 31 will indicate the operating status of the front differential lock device 132. As an example, the first display unit 31 may include a light-emitting unit built into a push-button switch that serves as the front differential lock operation unit 57, and the operating status of the front differential lock device 132 will be indicated by the state of its illumination (on, off, or flashing, etc.).

[0091] [3] Configuration related to the lifting device Next, the configuration related to the lifting device 17 of the work vehicle 10 according to this embodiment will be described in detail with reference to Figures 9, 12 to 14.

[0092] In this embodiment, the work implement 12, which is attached to the work implement connecting section 113 located at the rear of the machine body 11, can be raised and lowered by a lifting device 17. The lifting device 17 has a hydraulic cylinder 171 for lifting and lowering (see Figure 14), and raises and lowers the work implement 12 by extending and retracting the hydraulic cylinder 171 in response to the operation of the lifting lever located in the driver's unit 5.

[0093] Here, the lifting device 17 is not always operational, and the control control unit 23 of the control device 2 can restrict (prohibit) the operation of the lifting device 17. Specifically, under normal circumstances, the hydraulic fluid (hydraulic pressure) supplied to the hydraulic cylinder 171 of the lifting device 17 drives the hydraulic cylinder 171, resulting in a "hydraulic unlock state" that allows the lifting device 17 to raise and lower the work equipment 12. On the other hand, by stopping the supply of hydraulic fluid (hydraulic pressure) to the hydraulic cylinder 171 of the lifting device 17, the lifting device 17 can be restricted, resulting in a "hydraulic lock state".

[0094] Furthermore, the operator can switch between a "hydraulic unlock state," in which the lifting and lowering of the work implement 12 is permitted, and a "hydraulic lock state," in which the lifting and lowering of the work implement 12 is restricted (prohibited). In the "hydraulic lock state," only the lifting and lowering of the work implement 12 by the lifting device 17 is restricted; the operation of the work implement 12 itself is not particularly restricted.

[0095] Incidentally, in the work vehicle 10 according to this embodiment, the restriction operation unit 59 for switching between allowing and restricting the lifting and lowering movement of the work equipment 12 is located diagonally to the right rear of the driver's seat 51 inside the cabin 50, as shown in Figure 12 (and Figure 9). In addition, the restriction state indication unit 34 makes an indication according to the state of the restriction operation unit 59. That is, the work vehicle 10 comprises a body 11 to which the work equipment 12 can be attached, a restriction operation unit 59, and a restriction state indication unit 34. The restriction operation unit 59 receives operations to restrict the lifting and lowering movement of the work equipment 12. The restriction state indication unit 34 makes an indication according to the state of the restriction operation unit 59.

[0096] With this configuration, the operator can understand the status of the restrictive operation unit 59 by the indication from the restrictive status display unit 34. Therefore, compared to a configuration in which the lifting and lowering movement of the work equipment 12 is restricted (prohibited) by turning a hydraulic adjustment knob located at the feet of the operator while seated in the driver's seat 51 to close the slow return valve, the operator can more easily check the operating status of the restrictive operation unit 59 and understand its status. As a result, there is an advantage in that it is easier to improve the operability of the work vehicle 10.

[0097] More specifically, the restrictive operation unit 59 consists of a momentary push-button switch. When the restrictive operation unit 59 is pressed while the restrictive control unit 23 of the control device 2 is in a "hydraulic unlock state" which allows the lifting and lowering operation of the work equipment 12 by the lifting device 17, the restrictive control unit 23 controls a restrictive valve (solenoid valve) on the supply path for the hydraulic fluid (hydraulic) supplied to the hydraulic cylinder 171, thereby stopping the supply of hydraulic fluid. This puts the system into a "hydraulic lock state" which restricts the lifting and lowering operation of the work equipment 12 by the lifting device 17.

[0098] Conversely, when the lifting operation of the work equipment 12 by the lifting device 17 is restricted in a "hydraulic lock state," if the restricting operation unit 59 is pressed, the restricting control unit 23 controls the restricting valve (solenoid valve) on the supply path for the hydraulic fluid (hydraulic) supplied to the hydraulic cylinder 171, thereby restarting the supply of hydraulic fluid. This allows the lifting operation of the work equipment 12 by the lifting device 17 to be permitted, resulting in a "hydraulic unlock state."

[0099] Thus, in this embodiment, the switching between the "hydraulic unlock state" and the "hydraulic lock state" is electrically controlled (electronically controlled) using a regulating valve. In short, the work vehicle 10 is equipped with a regulating valve that restricts the lifting and lowering movement of the work machine 12 by an electrical signal corresponding to the operation of the regulating operation unit 59. Therefore, unlike when the slow return valve is operated directly, the regulating operation unit 59 can be positioned away from the regulating valve.

[0100] Here, the restriction status display unit 34 displays the restriction status (hydraulic unlock state / hydraulic lock state) of the lifting and lowering operation of the work machine 12. The restriction status display unit 34 is controlled by the restriction control unit 23 of the control device 2, and the displayed content (display mode) changes depending on whether it is in the hydraulic unlock state or the hydraulic lock state. In this embodiment, as an example, the restriction status display unit 34 includes a light-emitting unit built into the push-button switch which is the restriction operation unit 59, and indicates whether it is in the hydraulic unlock state or the hydraulic lock state by its light-emitting state (on, off, or blinking, etc.). For example, in the hydraulic lock state, the light-emitting unit as the restriction status display unit 34 lights up, and in the hydraulic unlock state, the light-emitting unit as the restriction status display unit 34 turns off. However, such an assignment of light-emitting states is just an example, and for example, in the hydraulic unlock state, the light-emitting unit as the restriction status display unit 34 lights up, and in the hydraulic lock state, the light-emitting unit as the restriction status display unit 34 turns off.

[0101] Thus, in this embodiment, the indication by the restriction status indication unit 34 includes indications corresponding to the restricted / unrestricted state of the lifting and lowering movement of the work implement 12. This allows the operator to grasp the current restricted state of the lifting and lowering movement of the work implement 12 using the restriction status indication unit 34. In particular, as in this embodiment, the restricted state of the lifting and lowering movement of the work implement 12 is indicated by the illumination state of the push-button switch itself, which serves as the restriction operation unit 59, making it easier for the operator to grasp the restricted state of the lifting and lowering movement of the work implement 12.

[0102] Furthermore, in this embodiment, the restriction status display unit 34 displays a display at least when an operation for raising or lowering the work implement 12 is performed. In other words, at the moment when the lifting lever for raising or lowering the work implement 12 is operated, the restriction status display unit 34 displays a display according to the restricted / unrestricted state of the lifting and lowering operation of the work implement 12. This makes it easier for the operator to understand the restricted state of the lifting and lowering operation of the work implement 12.

[0103] In particular, the restriction status display unit 34 displays a notification when an operation is performed to raise or lower the work implement 12, at least when the raising or lowering movement of the work implement 12 is restricted. That is, when the lifting lever for raising or lowering the work implement 12 is operated while the hydraulic lock state is active, the restriction status display unit 34 indicates that the work implement 12 is in a "hydraulic lock state" where its raising or lowering movement is restricted. This allows the operator to understand that if the work implement 12 does not raise or lower despite the operation of the lifting lever, it is because it is in a "hydraulic lock state". In this embodiment, the restriction status display unit 34 displays a notification according to the restricted / unrestricted state of the raising or lowering movement of the work implement 12 at all times, not just when an operation is performed to raise or lower the work implement 12.

[0104] Furthermore, the notification from the restriction status notification unit 34 includes a notification prompting the operator to release the restriction on the lifting and lowering movement. For example, when the lifting and lowering movement of the work equipment 12 is restricted, if an operation is performed to lift or lower the work equipment 12, the restriction status notification unit 34 will flash to prompt the operator to operate the restriction operation unit 59 to release the restriction on the lifting and lowering movement. This makes it possible to prompt the operator to operate the restriction operation unit 59 to set the work equipment 12 to the "hydraulic unlock state" if the work equipment 12 does not lift or lower despite the operation of the lifting lever.

[0105] Furthermore, the work vehicle 10 according to this embodiment is equipped with a driver's seat 51, and the control unit 59 is located to the side of the driver's seat 51. In this embodiment, as an example, the control unit 59 is located to the right of the driver's seat 51. Therefore, the operator can operate the control unit 59 while remaining seated in the driver's seat 51 by reaching for it.

[0106] Furthermore, the control unit 59 is located relatively rearward from the driver's seat 51. In this embodiment, for example, the control unit 59 is positioned behind the rear end of the driver's seat 51 (the back of the seatback). Therefore, it is possible to reduce the chance of the operator unintentionally operating the control unit 59.

[0107] Furthermore, as shown in Figure 13, the work vehicle 10 also displays information on the display device 19 according to the status of the restricting operation unit 59. In other words, the display device 19 displays information according to at least the status of the restricting operation unit 59. Figure 13 shows an example of the screen displayed on the display device 19 when the lifting lever for lifting the work equipment 12 is operated while the lifting operation of the work equipment 12 is restricted (hydraulic lock state). In this example, a message prompting the operator to operate (turn off) the restricting operation unit 59 (hydraulic lock switch) and then perform the lifting operation of the work equipment 12 again is displayed as a pop-up on the display screen of the display device 19.

[0108] This allows the operator to understand the current restriction status of the lifting and lowering movement of the work equipment 12 through the display on the display device 19.

[0109] Incidentally, as shown in Figure 14, the hydraulic cylinder 171 of the lifting device 17 has a cylinder portion 172, a cap portion 173 that closes one end of the cylinder portion 172, and a rod portion 174 that passes through a hole 176 in the cap portion 173. The hydraulic cylinder 171 is driven by hydraulic fluid to extend and retract the rod portion 174. A dust seal 177 is provided inside the hole 176 in the cap portion 173 to fill the gap with the rod portion 174.

[0110] Here, a groove 175 is formed on the surface (top surface) of the cap portion 173. The groove 175 communicates with the hole 176 of the cap portion 173. Through this groove 175, it is possible to drain water (rainwater, etc.) that accumulates in the hole 176 (on the dust seal 177). This makes it easier to prevent rust from forming on the outer surface of the rod portion 174.

[0111] In this embodiment, in a plan view, a plurality of grooves 175 are provided extending from the hole 176 in at least two directions. This allows water to drain in at least two directions, which reduces the constraints on the mounting direction of the cap portion 173, for example, and improves assembly workability.

[0112] Furthermore, the multiple grooves 175 are arranged at equal intervals in the circumferential direction of the hole 176. In this embodiment, as an example, the cap portion 173 is circular in plan view, and two grooves 175 are arranged at 180-degree intervals in the circumferential direction of the hole 176. This is not limited to this example; for example, three grooves 175 may be arranged at 120-degree intervals in the circumferential direction of the hole 176. This further reduces the constraints on the mounting direction of the cap portion 173.

[0113] Furthermore, the bottom surface of the groove 175 is parallel to the surface (top surface) of the cap portion 173, or is inclined with respect to the surface (top surface) of the cap portion 173 such that the groove 175 becomes deeper towards the outer circumference of the cap portion 173. This prevents water from flowing through the groove 175 into the inner circumference (hole 176) of the cap portion 173, or the water gradient within the groove 175 makes it easier for water to flow to the outer circumference of the cap portion 173, thereby improving the drainage effect.

[0114] The cap portion 173 is attached to the cylinder portion 172 by tightening the male threads formed on its outer circumference against the female threads formed on its inner circumference. This makes it easy to attach and detach the cap portion 173 from the cylinder portion 172, improving assembly and maintenance. Even with this configuration, the constraints on the mounting direction of the cap portion 173 are reduced because multiple grooves 175 extend in at least two directions.

[0115] [4] Brake mechanism related configuration Next, the configuration related to the brake mechanism 15 of the work vehicle 10 according to this embodiment will be described in detail with reference to Figures 15 to 18.

[0116] The work vehicle 10 is equipped with a pair of brake mechanisms 15 corresponding to a pair of brake wheels (rear wheels 112). One of the brake mechanisms 15 brakes the left rear wheel 112, and the other brake mechanism 15 brakes the right rear wheel 112. This makes it possible for the work vehicle 10 to implement an "auto-brake," for example, in which one of the brake mechanisms 15 performs a braking action on the inner rear wheel 112 when the steering angle of the steering 52 exceeds a predetermined angle.

[0117] As shown in Figure 15, the work vehicle 10 is equipped with a brake drive unit 7 for driving a pair of brake mechanisms 15 in the event of automatic braking or the like. The brake drive unit 7 is located on the upper surface of the transmission case 115. The brake drive unit 7 is connected to the pair of brake mechanisms 15 via a pair of wires 70, and the pair of wires 70 operates each of the pair of brake mechanisms 15.

[0118] As shown in Figure 16, the brake drive unit 7 includes a pair of brake cylinders 71, a pair of brake valves 72 (auto brake valves), and a pair of linkage mechanisms 73. The pair of brake cylinders 71 are hydraulic cylinders that operate when hydraulic fluid is supplied via a pair of brake valves 72. Each of the pair of brake valves 72 consists of a controllable switching valve such as an electromagnetic valve, and operates the pair of brake cylinders 71 by controlling the supply of hydraulic fluid to the pair of brake cylinders 71.

[0119] The pair of linkage mechanisms 73 connect the rods 711 (pistons) of the pair of brake cylinders 71 to the pair of wires 70, respectively. In other words, when the pair of brake cylinders 71 are driven, the pair of brake mechanisms 15 are operated via the pair of linkage mechanisms 73 and the pair of wires 70.

[0120] One of the pair of brake cylinders 71 drives one brake mechanism 15 via one linkage mechanism 73 and wire 70, and this brake mechanism 15 brakes the left brake wheel (rear wheel 112). The other brake cylinder 71 drives the other brake mechanism 15 via the other linkage mechanism 73 and wire 70, and this brake mechanism 15 brakes the right brake wheel (rear wheel 112).

[0121] The brake drive unit 7 configured in this way is fixed to the upper surface of the transmission case 115. In particular, in this embodiment, the transmission case 115 is composed of three cases that are divided in the front-rear direction D2, and the brake drive unit 7 is positioned on the upper surface of the case located at the front of the three cases.

[0122] More specifically, the brake drive unit 7, as shown in Figure 17, further comprises a housing 74, a pivot point 75, and a fixing plate 76. A pair of brake cylinders 71 and a pair of brake valves 72 are integrated within the housing 74. The pair of brake cylinders 71 are arranged side by side in the left-right direction D3. The pair of brake valves 72 are arranged side by side in the left-right direction D3 in front of the pair of brake cylinders 71.

[0123] Here, the pair of brake cylinders 71 are positioned such that the direction of movement of their pistons is in the front-rear direction D2. Each of the pair of brake cylinders 71 has a rod 711 that protrudes rearward from its rear end, and the rods 711 are connected to the wire 70 via a link mechanism 73. Specifically, the left brake cylinder 71 is connected to the right wire 70 via one link mechanism 73, and the right brake cylinder 71 is connected to the left wire 70 via the other link mechanism 73.

[0124] Each of the pair of link mechanisms 73 is rotatably supported at a pivot point 75 located at the rear of the housing 74. The pivot point 75 is an axial member having a length in the vertical direction D1, and the pair of link mechanisms 73 are rotatable about the pivot point 75 in a plan view. The fixing plate 76 is a metal plate having a length in the front-rear direction D2, and fixes the pivot point 75 by being spanned between the upper surface of the housing 74 and the upper end of the pivot point 75.

[0125] With the configuration described above, when the left brake valve 72 causes the left brake cylinder 71 to push the rod 711 backward, the right wire 70 is pulled via one linkage mechanism 73, and the right brake mechanism 15 is activated. Similarly, when the right brake valve 72 causes the right brake cylinder 71 to push the rod 711 backward, the left wire 70 is pulled via the other linkage mechanism 73, and the left brake mechanism 15 is activated.

[0126] As described above, the work vehicle 10 according to this embodiment comprises a body 11 having a pair of brake wheels (rear wheels 112), a pair of brake mechanisms 15, and a pair of brake cylinders 71. The brake mechanism 15 brakes the pair of brake wheels. The pair of brake cylinders 71 correspond to the pair of brake wheels and drive the brake mechanism 15. Here, the pair of brake cylinders 71 are arranged in a position that moves their pistons along the longitudinal direction D2 of the body 11.

[0127] In this configuration, the pair of brake cylinders 71 are arranged such that the direction of piston movement is perpendicular to the machine body 11 (towards the front-rear direction D2). Therefore, compared to a configuration in which the pair of brake cylinders 71 are arranged perpendicular to the machine body 11, it is easier to make the lengths of the wires 70 connecting the pair of brake cylinders 71 to the left and right brake mechanisms 15 equal on both sides. As a result, the work vehicle 10 according to this embodiment has the advantage that the desired braking characteristics can be easily obtained.

[0128] Furthermore, as shown in Figure 16, the pair of brake cylinders 71 are positioned in the center of the left-right direction D3 of the aircraft body 11 (the center of the left-right direction D3 of the transmission case 115). This makes it easier to equalize the length of the wires 70 connecting the pair of brake cylinders 71 to the left and right brake mechanisms 15 on both sides. It also leads to an improvement in the left-right weight balance.

[0129] Furthermore, in the left-right direction D3 of the aircraft body 11, the midpoint P1 of the pair of braking wheels (rear wheels 112) (see Figure 15) is located between the pair of brake cylinders 71 (see Figure 16). In other words, in the left-right direction D3, the midpoint P1 of the pair of braking wheels (rear wheels 112) is located between the ends of the pair of brake cylinders 71. This makes it easier to equalize the length of the wires 70 connecting the pair of brake cylinders 71 to the left and right brake mechanisms 15 on both sides.

[0130] Furthermore, the pair of brake cylinders 71 have a symmetrical structure in the left-right direction D3 of the machine body 11. In other words, the pair of brake cylinders 71 are configured symmetrically. This makes it easier to equalize the length of the wires 70 connecting the pair of brake cylinders 71 to the left and right brake mechanisms 15 on both sides.

[0131] Furthermore, the work vehicle 10 is equipped with a pair of wires 70 extending from a pair of brake cylinders 71 toward a pair of brake wheels (rear wheels 112). In other words, the pair of wires 70 extend toward the rear from the pair of brake cylinders 71 (via a pair of linkage mechanisms 73) and are connected to a pair of brake mechanisms 15. This makes it easier to equalize the length of the wires 70 connecting the pair of brake cylinders 71 to the left and right brake mechanisms 15 on both sides.

[0132] Furthermore, the work vehicle 10 according to this embodiment is equipped with a pair of link mechanisms 73, each corresponding to a pair of brake cylinders 71 and driven by the pair of brake cylinders 71. The pair of link mechanisms 73 operate with the same pivot point 75 as the pivot point. Therefore, the pair of link mechanisms 73 can be made compact, and the number of parts for the pair of link mechanisms 73 can be the same, making it less likely for differences to occur between the left and right sides due to the effects of rattle. In addition, in the vertical direction D1, the pair of link mechanisms 73 have degrees of freedom, so they are less likely to be restricted in their layout by surrounding parts.

[0133] Furthermore, the pivot point 75 is a shaft member having a length in the vertical direction D1, with both ends in the longitudinal direction being supported. That is, the upper end of the pivot point 75 is supported by the fixing plate 76, and the lower end of the pivot point 75 is supported by the transmission case 115 (via a stay). This allows the pivot point 75 to be firmly supported, preventing it from bending due to, for example, a pressing load from a pair of brake cylinders 71.

[0134] Furthermore, as shown in Figure 18, the pair of brake cylinders 71 are positioned above the transmission case 115, which has a power transmission mechanism. In other words, the brake drive unit 7, including the pair of brake cylinders 71, is positioned on the upper surface of the transmission case 115. This makes it easier to avoid the brake cylinders 71 coming into contact with the ground when the work vehicle 10 is in motion, or foreign objects such as stones kicked up by the front wheels 111 coming into contact with the brake cylinders 71.

[0135] Furthermore, the pair of brake cylinders 71 are positioned in the space between the transmission case 115 and the passenger compartment (driver's compartment 5). In other words, the brake drive unit 7, including the pair of brake cylinders 71, is located on the upper surface of the transmission case 115 and below the floor (flooring material) of the driver's compartment 5. Therefore, the brake cylinders 71 can be accessed, for example, from the side or from the driver's compartment 5 side by removing the floor of the driver's compartment 5, improving the maintainability of the brake cylinders 71.

[0136] [5] Hydraulic pump related configuration Next, the configuration related to the hydraulic pump 16 in the work vehicle 10 according to this embodiment will be described in detail with reference to Figures 19 to 25.

[0137] The hydraulic pump 16 is driven by power transmitted from the power source 6 via a power transmission mechanism, and supplies hydraulic fluid to various hydraulic devices (hydraulic cylinders, hydraulic clutches, etc.) to operate the hydraulic system. In this embodiment, as an example, as shown in Figures 19 to 21, the hydraulic pump 16 is located below the operating unit 5 and on one side (in this case, the right side) of the transmission case 115 of the machine body 11 in the left-right direction D3.

[0138] More specifically, a gear case 83 is mounted on the right side of the transmission case 115. The gear case 83 houses a power extraction mechanism for transmitting power from the power source 6 to the hydraulic pump 16 to drive the hydraulic pump 16. The power extraction mechanism in the gear case 83 extracts power from the power transmission mechanism in the transmission case 115 and outputs this power to the hydraulic pump 16 to drive the hydraulic pump 16.

[0139] Furthermore, the hydraulic pump 16 has at least a first pump 81 and a second pump 82. The power extraction mechanism in the gear case 83 transmits power extracted from the power transmission mechanism in the transmission case 115 to both the first pump 81 and the second pump 82.

[0140] In other words, the work vehicle 10 according to this embodiment comprises a machine body 11 having a power source 6, a hydraulic pump 16, and a gear case 83. The hydraulic pump 16 is driven by the power of the power source 6 and discharges hydraulic fluid. The gear case 83 houses a power extraction mechanism that transmits the power of the power source 6 to the hydraulic pump 16. Here, the hydraulic pump 16 has a first pump 81 and a second pump 82. The first pump 81 and the second pump 82 are arranged on both sides of the gear case 83 so as to sandwich it.

[0141] With this configuration, the hydraulic pump 16, including the first pump 81 and the second pump 82, can be positioned by utilizing the space on both sides of the gear case 83, which is provided for extracting power from the power source 6. As a result, the first pump 81 and the second pump 82 can be positioned near the gear case 83, making it easier to keep the distance of the hydraulic pump 16 from the gear case 83 small and simplifying the structure for power transmission from the gear case 83 (gear mechanism), thus reducing power transmission losses. Consequently, the work vehicle 10 according to this embodiment has the advantage of easily simplifying the structure for power transmission to the hydraulic pump 16.

[0142] Furthermore, the gear case 83 is positioned to the side of the transmission case 115 (to the right in this embodiment). This allows the power extraction mechanism within the gear case 83 to directly extract power from the power transmission mechanism within the transmission case 115.

[0143] Here, the first pump 81 is a variable displacement type, and the second pump 82 is a fixed displacement type. For example, the first pump 81 is a variable displacement piston pump (axial piston pump or radial piston pump) that can change the discharge amount (flow rate) of hydraulic fluid, and discharges hydraulic fluid by reciprocating a piston in accordance with the rotation of the input shaft. The second pump 82 is a fixed displacement gear pump (gear pump) with a constant discharge amount (flow rate) of hydraulic fluid, and discharges hydraulic fluid by rotating a gear in accordance with the rotation of the input shaft. The first pump 81 supplies hydraulic fluid to the work machine 12 and the lifting device 17, etc., and the second pump 82 supplies hydraulic fluid to the traveling device 13, etc.

[0144] This makes it possible to compactly mount the first pump 81 and the second pump 82, which are of different types, while driving them with power from a single gear case 83.

[0145] Here, the first pump 81, the gear case 83, and the second pump 82 are arranged in the front-to-back direction D2 of the aircraft body 11. Since the gear case 83 is mounted on the right side of the transmission case 115, the first pump 81, the gear case 83, and the second pump 82 are arranged in a straight line in the front-to-back direction D2 on the right side of the transmission case 115. In this embodiment, as an example, the first pump 81, the gear case 83, and the second pump 82 are arranged from rear to rear in the order of first pump 81, gear case 83, and second pump 82.

[0146] This makes it possible to keep the left-right dimension D3 of the body 11 of the work vehicle 10 small. In other words, for example, compared to a configuration in which the first pump 81 and / or the second pump 82 are aligned with the gear case 83 in the left-right dimension D3 of the body 11, the protrusion (amount of projection) of the hydraulic pump 16 laterally from the transmission case 115 can be kept small. Therefore, for example, even in a work vehicle 10 with a narrow tread specification in which the width of the pair of rear wheels 112 is narrow, it becomes easier to position the hydraulic pump 16 without interfering with the pair of rear wheels 112.

[0147] Furthermore, rotational force is transmitted to the first pump 81 and the second pump 82 from the gear case 83 around the same axis. In other words, as shown in Figure 23, the gear case 83 has an output shaft Ax10 that rotates around a rotation axis Ax1 along the longitudinal direction D2 of the machine body 11, and the input shafts Ax20 of the first pump 81 and the second pump 82 are arranged on the same axis as the output shaft Ax10. Figure 23 is a schematic cross-sectional view of the first pump 81, the second pump 82 and the gear case 83. Cross-sectional hatching is omitted in Figure 23.

[0148] This allows the rotational force from the gear case 83 to be directly input to the first pump 81 and the second pump 82, making it easier to simplify the gear mechanism. Furthermore, since the first pump 81 and the second pump 82 are arranged on the same axis (rotation axis Ax1), it becomes easier to balance the weight and suppress a decrease in strength.

[0149] Here, the second pump 82 includes a drive gear pump 821 and a charge pump 822. The hydraulic fluid discharged from the charge pump 822 is supplied to the first pump 81. The drive gear pump 821 and the charge pump 822 included in the second pump 82 are mechanically connected. In other words, the drive gear pump 821 and the charge pump 822 are in conjunction. Therefore, the power extraction mechanism in the gear case 83 drives both the drive gear pump 821 and the charge pump 822 by transmitting power extracted from the power transmission mechanism in the transmission case 115 to the second pump 82.

[0150] As a result, the first pump 81 is supplied with hydraulic fluid pressurized by the charge pump 822, making it easier to increase the pressure of the hydraulic fluid discharged from the first pump 81.

[0151] Furthermore, the orientation of the hydraulic fluid inlet and outlet is common to both the first pump 81 and the second pump 82. In this embodiment, as an example, as shown in Figure 22, the inlet 811 of the first pump 81, the inlet 823 of the drive gear pump 821 in the second pump 82, and the inlet 824 of the charge pump 822 are all facing downwards. On the other hand, as shown in Figure 22, the outlet 812 of the first pump 81, the outlet 825 of the drive gear pump 821 in the second pump 82, and the outlet 826 of the charge pump 822 are all facing upwards.

[0152] In this way, by aligning the orientation of the hydraulic fluid inlet and outlet, the piping that supplies hydraulic fluid to the first pump 81 and the second pump 82, and the piping that carries the hydraulic fluid discharged from the first pump 81 and the second pump 82, can be arranged compactly.

[0153] Here, as shown in Figures 20 and 21, the work vehicle 10 is equipped with a line filter 841. The line filter 841 is inserted into the hydraulic fluid supply passage (piping 851) from the charge pump 822 to the first pump 81. Furthermore, the work vehicle 10 is equipped with a suction filter 842 which is inserted into the hydraulic fluid supply passage (piping 852) to the second pump 82.

[0154] In this configuration, the hydraulic fluid is supplied from the tank through the suction filter 842 and then through the piping 852 to the drive gear pump 821 and charge pump 822 of the second pump 82. The relatively coarse suction filter 842 removes foreign matter mixed in the hydraulic fluid when it is supplied to the second pump 82, ensuring a certain level of cleanliness. Then, the hydraulic fluid discharged from the charge pump 822 is supplied to the first pump 81 through the piping 851 and the line filter 841. The relatively fine line filter 841 provides hydraulic fluid with a higher level of cleanliness, so it is possible to supply highly clean hydraulic fluid to hydraulic equipment with high cleanliness requirements, such as piston pumps and solenoid valves.

[0155] Here, the suction filter 842 is positioned below the second pump 82 (in the vertical direction D1). Specifically, the suction filter 842 is positioned below the lower ends of the travel gear pump 821 and charge pump 822 of the second pump 82. As a result, the suction filter 842 can be positioned near the hydraulic pump 16, but overlapping with the hydraulic pump 16 in a plan view, thus achieving a compact arrangement.

[0156] Furthermore, the piping 852 that forms the hydraulic fluid supply path between the charge pump 822 and the first pump 81 is flexible in at least a portion of it. In this embodiment, the piping 852 between the charge pump 822 and the line filter 841 is made of a hydraulic hose. Therefore, the routing of the hydraulic fluid supply path between the charge pump 822 and the first pump 81 is improved, and a compact arrangement can be achieved.

[0157] Incidentally, the line filter 841 is positioned below the first pump 81 (in the vertical direction D1). Specifically, the line filter 841 is positioned below the lower end of the first pump 81 and to the side (right side) of the suction filter 842 (see Figure 19). With this arrangement, the piping from the line filter 841 to the first pump 81 can be made compact.

[0158] On the other hand, in the case of a work vehicle 10 with a narrow tread specification, for example, it is preferable to place the line filter 841 at the position shown by the dashed line (double dot line) in Figure 22. In the example in Figure 22, the line filter 841 is placed in front of the second pump 82. Specifically, the line filter 841 is placed in front of the front end of the travel gear pump 821 of the second pump 82. With this arrangement of the line filter 841, the left-right dimension D3 of the body 11 of the work vehicle 10 can be kept small.

[0159] Furthermore, the work vehicle 10 is further equipped with a flow divider 86, as shown in Figure 24. The flow divider 86 is positioned above the first pump 81 and divides the hydraulic fluid discharged from the first pump 81. In other words, the flow divider 86 is connected to the discharge port 812 of the first pump 81 and branches the hydraulic fluid discharged from the first pump 81 into multiple oil passages. This makes it possible to distribute the hydraulic fluid discharged from the first pump 81 to multiple hydraulic systems. In particular, since the hydraulic fluid is divided immediately after being discharged from the first pump 81, the oil passage from the first pump 81 to the flow divider 86 can be shortened, making it possible to suppress pressure loss.

[0160] In the example shown in Figure 24, the flow divider 86 has a first branch port 861, a second branch port 862, and a third branch port 863, which divide the hydraulic fluid discharged from the first pump 81 into three oil passages. Here, as an example, a lifting device 17 is connected to the first branch port 861, a work implement 12 is connected to the second branch port 862, and a work implement that is mounted on the front side of a machine body 11, such as a front loader, is connected to the third branch port 863.

[0161] Furthermore, the work vehicle 10 is further equipped with a connecting member 87, as shown in Figure 25. The connecting member 87 is positioned below the first pump 81 and connected to the suction port 811 of the first pump 81. In other words, the connecting member 87 is inserted between the line filter 841 and the first pump 81, and takes in the hydraulic fluid discharged from the charge pump 822 to the suction port 811 of the first pump 81. The connecting member 87 has a charge relief 871, which controls the charge circuit pressure.

[0162] Furthermore, the work vehicle 10 is further equipped with a relay member 88, as shown in Figure 20. The relay member 88 is connected to the discharge port 812 of the first pump 81 via piping (including a flow divider member 86) and is configured to be connectable to target equipment. In this embodiment, as an example, the third branch port 863 of the flow divider member 86 is connected to the relay member 88. Here, the relay member 88 is positioned in front of the second pump 82. Specifically, the relay member 88 is positioned in front of the front end of the travel gear pump 821 of the second pump 82.

[0163] The provision of such a relay member 88 makes it possible to freely change the hydraulic equipment (target equipment) to which the hydraulic fluid is supplied from the first pump 81. The relay member 88 is positioned in front of the rear wheel 112 in a side view (see Figure 20), which allows access to the relay member 88 without removing the rear wheel 112, thereby improving work efficiency.

[0164] [6] Configuration related to the cooling system Next, the configuration related to the cooling system 18 of the work vehicle 10 according to this embodiment will be described in detail with reference to Figures 26 to 32.

[0165] As shown in Figures 26 and 27, the work vehicle 10 is equipped with a bonnet 114 at the front of the machine body 11, and a cooling device 18 and a power source 6, etc., are located in a position covered by the bonnet 114. The work vehicle 10 is further equipped with side panels 116 located below the bonnet 114, and at least the sides of the cooling device 18 and the power source 6, etc., are covered by the side panels 116.

[0166] The hood 114 is openable and closable, and the side panels 116 are removable. This allows access to the cooling system 18 and power source 6, etc., located in positions covered by the hood 114 and side panels 116, enabling maintenance. The hood 114 and side panels 116 are not shown in Figures 27 to 32.

[0167] As shown in Figure 27, the cooling device 18 has a radiator 61 positioned upright in front of the power source 6. In a front view, the radiator 61 is formed in a rectangular shape with a length in the vertical direction D1, and is positioned so that its thickness coincides with the front-to-back direction D2.

[0168] The cooling system 18 includes a cooling fan 62 in addition to a radiator 61. The cooling fan 62 is positioned between the radiator 61 and the power source 6, with its axis facing the front-rear direction D2. The cooling fan 62 is connected to the power source 6 and rotates in conjunction with the operation of the power source 6, generating an airflow (cooling air) from the front (radiator 61 side) to the rear (power source 6 side) of the aircraft body 11.

[0169] As a result, airflow is drawn into the radiator 61 from the front side of the aircraft 11 (opposite side from the cooling fan 62). In other words, the airflow passing through the radiator 61 from front to back becomes the cooling air, and the radiator 61 is cooled. As the radiator 61 is cooled, it cools the refrigerant (cooling water) passing through the power source 6.

[0170] As shown in Figures 27 to 30, the cooling system 18 further includes an intercooler 63, an oil cooler 64, a condenser 65, and a fuel cooler 66. The intercooler 63 cools the air supplied to the power source 6. The oil cooler 64 cools the hydraulic fluid. The condenser 65 is a condenser for the air conditioning system provided in the operating unit 5 and cools the refrigerant of the air conditioning system. The fuel cooler 66 cools the fuel for the power source 6.

[0171] The intercooler 63 and oil cooler 64 are located in front of the radiator 61 (upstream of the airflow). The intercooler 63 is located above the oil cooler 64 (see Figure 29). The condenser 65 is located in front of the oil cooler 64 (upstream of the airflow). The fuel cooler 66 is located in front of the condenser 65 (upstream of the airflow).

[0172] As a result, the airflow (cooling air) generated when the cooling fan 62 is driven is divided into two directions, vertically D1. The upper airflow then passes through the intercooler 63 and the upper part of the radiator 61 in that order, while the lower airflow passes through the fuel cooler 66, condenser 65, oil cooler 64, and the lower part of the radiator 61 in that order.

[0173] Furthermore, the cooling device 18 also includes a radiator screen 9. The radiator screen 9 is a mesh-like material positioned in front of the radiator 61 (upstream of the airflow) and filters out dust and debris sent to the radiator 61 along with the airflow (cooling air), preventing dust and debris from adhering to the radiator 61.

[0174] Incidentally, as shown in Figures 29 and 30, the radiator screen 9 has a first screen 91 and a second screen 92. In other words, the radiator screen 9 is not a single piece, but is composed of multiple screens (two in this embodiment) (the first screen 91 and the second screen 92).

[0175] The first screen 91 and the second screen 92 are arranged so as to be aligned in the vertical direction D1 when viewed from the front. The first screen 91 is positioned above the second screen 92, and when viewed from the front, the lower end of the first screen 91 overlaps with the upper end of the second screen 92. As a result, the radiator screen 9 covers almost the entire front surface of the radiator 61 with both the first screen 91 and the second screen 92.

[0176] The first screen 91 is formed in a rectangular shape with a length in the left-right direction D3 when viewed from the front, and is positioned in an upright position with its thickness equal to the front-back direction D2. The second screen 92 is formed in a rectangular shape with a length in the left-right direction D3 when viewed from the front, and is positioned in an upright position with its thickness equal to the front-back direction D2. In this embodiment, the first screen 91 and the second screen 92 have the same dimensions in the longitudinal direction (left-right direction D3), but the first screen 91 has a smaller dimension in the short direction (up-down direction D1).

[0177] The first screen 91 is positioned in front of the intercooler 63 (upstream of the airflow). The first screen 91 is directly attached to the intercooler 63 so as to be in contact with the front of the intercooler 63. As a result, the first screen 91 is positioned in front of the top of the radiator 61 via the intercooler 63.

[0178] The second screen 92 is positioned between the oil cooler 64 and the radiator 61. The second screen 92 is directly attached to the radiator 61 so as to be in contact with the front of the lower part of the radiator 61. As a result, the second screen 92 is positioned in front of the lower part of the radiator 61.

[0179] As described above, in the longitudinal direction D2 of the aircraft 11, the first screen 91 is positioned relatively forward of the second screen 92. In other words, the first screen 91 is positioned offset forward (upstream of the airflow) of the second screen 92 by the amount of the intercooler 63.

[0180] The first screen 91 and the second screen 92, configured in this manner, are each detachably attached to the aircraft body 11. Therefore, during maintenance, it is possible to replace the first screen 91 and the second screen 92 separately.

[0181] As described above, the work vehicle 10 according to this embodiment comprises a body 11 having a radiator 61, a radiator screen 9, and a heat exchanger (intercooler 63, etc.). The radiator screen 9 is positioned upstream (forward) of the airflow taken into the radiator 61. The heat exchanger is positioned upstream (forward) of the airflow relative to the radiator 61. The radiator screen 9 has a first screen 91 and a second screen 92, which are divided when viewed from the upstream side of the airflow. Here, the first screen 91 is positioned at least upstream (forward) of the airflow relative to the heat exchanger.

[0182] The term "heat exchanger" as used herein refers to various heat exchangers that have the function of receiving airflow (cooling air) and performing heat exchange, and includes, for example, at least one of an intercooler, oil cooler, condenser, and fuel cooler. In this embodiment, the intercooler 63 is an example of a "heat exchanger". That is, the first screen 91 is positioned at least upstream (forward) of the airflow relative to the intercooler 63, which acts as a heat exchanger.

[0183] In this configuration, a portion of the radiator screen 9 (the first screen 91) functions not only as a screen for the radiator 61 but also as a screen to prevent the adhesion of dirt and dust to the heat exchanger (intercooler 63). In other words, since the first screen 91 is used for both the radiator 61 and the heat exchanger (intercooler 63), the number of parts can be reduced compared to the case where a separate screen is provided for the heat exchanger (intercooler 63). As a result, there is the advantage of being able to use the radiator screen 9 more efficiently.

[0184] In this embodiment, the heat exchanger (intercooler 63) is positioned upstream (in front of) the airflow relative to the radiator 61. As a result, the airflow that has passed through the heat exchanger (intercooler 63) is taken into the radiator 61, which helps to suppress the decrease in cooling efficiency in the heat exchanger.

[0185] Furthermore, the first screen 91 is positioned relatively above the second screen 92. In other words, the radiator screen 9 is divided in the vertical direction D1. Therefore, for example, it becomes possible to remove only one of the first screen 91 or the second screen 92 from the side in the left-right direction D3 of the aircraft body 11, thereby improving maintainability.

[0186] Furthermore, the first screen 91 and the second screen 92 are positioned offset in the front-rear direction D2 of the aircraft body 11. In this embodiment, as described above, the first screen 91 is offset forward (upstream of the airflow) of the second screen 92 by the amount of the heat exchanger (intercooler 63). This makes it less likely for the first screen 91 or the second screen 92 to interfere with the other when removing only one of them, thereby improving maintainability.

[0187] Furthermore, portions of the first screen 91 and the second screen 92 overlap when viewed from the upstream (front) side of the airflow. Specifically, the lower end of the first screen 91 overlaps with the upper end of the second screen 92. As a result, the first screen 91 and the second screen 92 can cover the entire area of ​​the radiator 61 without any gaps when viewed from the upstream (front) side of the airflow.

[0188] Furthermore, as shown in Figure 28, wall portions 93 are positioned on both sides of the machine body 11 in the width direction (left-right direction D3) relative to the space between the radiator 61 and the heat exchanger (intercooler 63). In other words, a pair of wall portions 93 close off both sides of the space between the radiator 61 and the heat exchanger (intercooler 63) in the left-right direction D3. In this embodiment, a slit 94 for attaching and detaching the second screen 92 is formed in at least one side (left side) of the wall portion 93. The left wall portion 93 is not shown in Figures 29 to 32.

[0189] With this configuration, even if there is a space between the first screen 91 and the radiator 61, it is possible to prevent airflow from entering that space from the side. As a result, it becomes easier to take in the airflow that has passed through the first screen 91 into the radiator 61, and it is possible to prevent airflow that has not passed through the first screen 91 from being taken into the radiator 61.

[0190] Incidentally, in this embodiment, as shown in Figures 31 and 32, a structure is adopted for detachably attaching the first screen 91 and the second screen 92 from one side (in this case, the left side) of the aircraft body 11 in the left-right direction D3. As a result, the first screen 91 and the second screen 92 can be attached and detached when the openable bonnet 114 is open, improving maintainability.

[0191] Specifically, the first screen 91 is supported at both ends in the vertical direction D1 by a first upper support portion 951 and a first lower support portion 952. Specifically, the first upper support portion 951 has a groove shape that is long in the left-right direction D3 and open downwards, and the first lower support portion 952 has a groove shape that is long in the left-right direction D3 and open upwards. The first upper support portion 951 is provided only in the center of the intercooler 63 in the left-right direction D3, and the first lower support portion 952 is provided along the entire length of the intercooler 63 in the left-right direction D3. Furthermore, the left end of the first screen 91 is fastened to a first lock portion 953.

[0192] As a result, when the first locking part 953 is locked, the first screen 91 is positioned in all directions: vertical D1, front-rear D2, and left-right D3. On the other hand, when the first locking part 953 is unlocked, the first screen 91, while positioned in the vertical D1 and front-rear D2 directions, can slide in the left-right D3 direction while being guided by the first upper support part 951 and the first lower support part 952.

[0193] In short, the first screen 91 is detachably attached to the aircraft body 11 by an operation that includes sliding movement. This allows the first screen 91 to be removed by pulling it out to the side (to the left in this embodiment), improving maintainability.

[0194] On the other hand, the second screen 92 is supported at both ends in the vertical direction D1 by a second upper support portion 961 (see Figure 32) and a second lower support portion 962. Specifically, the second upper support portion 961 has a groove shape that is long in the left-right direction D3 and open downwards, and the second lower support portion 962 has a groove shape that is long in the left-right direction D3 and open upwards. The second upper support portion 961 is provided only at the right end of the radiator 61 in the left-right direction D3, and the second lower support portion 962 is provided along the entire length of the radiator 61 in the left-right direction D3. Furthermore, the left end of the second screen 92 is fastened to a second lock portion 963.

[0195] As a result, when the second locking part 963 is locked, the second screen 92 is positioned in all directions: vertical D1, front-to-back D2, and left-to-right D3. On the other hand, when the second locking part 963 is unlocked, the second screen 92, while positioned in the vertical D1 and front-to-back D2 directions, can slide in the left-to-right direction D3 while being guided by the second upper support part 961 and the second lower support part 962.

[0196] Here, unlike the first screen 91, the second screen 92 has a second upper support portion 961 that supports its upper end, which is provided only at the end opposite to the removal side (left side) in the left-right direction D3 (right side). Therefore, as shown by the dashed line (two-dot line) in Figure 32, the second screen 92 can be rotated so that its left end is lifted upwards when it is pulled out slightly to the left, and in this state it can be pulled out diagonally upwards to the left.

[0197] In short, the second screen 92 is detachably attached to the aircraft body 11 by an operation that includes rotational movement. This allows the second screen 92 to be removed even in a more limited space, even if it cannot be pulled out to the side (to the left in this embodiment), thus improving maintainability.

[0198] [7] Variant The following lists some modifications of Embodiment 1. The modifications described below can be combined and applied as appropriate.

[0199] The work vehicle 10 may have a driver's unit 5 that is not limited to a cabin specification, but may also have a canopy specification or a lops specification, for example.

[0200] Furthermore, the heat exchanger located downstream of the airflow relative to the first screen 91 is not limited to the intercooler 63, but may include at least one of the following: an intercooler, an oil cooler, a condenser, and a fuel cooler. For example, multiple heat exchangers, such as the intercooler 63 and the oil cooler 64, may be arranged downstream of the airflow relative to the first screen 91.

[0201] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0202] <Note 1> An aircraft having a pair of rear wheels, The driver's seat and, A rear differential lock device that limits the differential movement of the pair of rear wheels, It comprises a rear differential lock operating unit that receives an operation to activate the rear differential lock device, The rear differential lock operating unit is located in front of the driver's seat. Work vehicle.

[0203] <Note 2> The dashboard is further located in front of the driver's seat, The rear differential lock operating unit is located on the dashboard. Work vehicles as described in Appendix 1.

[0204] <Note 3> It is positioned in a location corresponding to the rear differential lock operating section and further includes an indicator mark representing the function of the rear differential lock operating section. Work vehicles as described in Appendix 1 or 2.

[0205] <Note 4> The steering wheel is further located in front of the driver's seat, In a side view, the rear differential lock operating part is positioned higher than the lower end of the steering wheel. A work vehicle as described in any of the appendices 1 to 3.

[0206] <Note 5> The system further includes a first display unit that displays the operating status of the rear differential lock device. A work vehicle as described in any of the appendices 1 to 4.

[0207] <Note 6> The rear differential lock device is activated when the rear differential lock operating unit is operated while the activation conditions are met. The system further includes a notification unit that provides notification if the rear differential lock operating unit is operated while the aforementioned activation conditions are not met. A work vehicle as described in any of the appendices 1 to 5.

[0208] <Note 7> The rear differential lock device is activated when the rear differential lock operating unit is operated while the activation conditions are met. The system further includes a second display unit that indicates whether or not the aforementioned activation conditions are met. A work vehicle as described in any of the appendices 1 to 6.

[0209] <Note 8> The system further comprises a pair of brake devices for braking each of the aforementioned pair of rear wheels, The rear differential lock device is activated when the rear differential lock operating unit is operated while the activation conditions are met. The activation condition includes the fact that the pair of brake devices are in a brake-linked state in which they are linked together. A work vehicle listed in any of the appendices 1 to 7.

[0210] <Note 9> A front differential lock device that limits the differential of the pair of front wheels of the aforementioned aircraft, The system further includes a front differential lock operating unit that receives an operation to activate the front differential lock device, A work vehicle as described in any of the appendices 1 to 8.

[0211] <Note 10> The rear differential lock operating unit and the front differential lock operating unit are arranged side by side in front of the driver's seat. Work vehicles as described in Appendix 9.

[0212] <Note 11> The rear differential lock device is activated when the rear differential lock operating unit is operated while the rear activation conditions are met. The front differential lock device is activated when the front differential lock operating unit is operated while the conditions for activation of the front differential are met. The rear activation conditions and the front activation conditions can be set individually. Work vehicles as described in Appendix 9 or 10. [Explanation of symbols]

[0213] 10 Work Vehicles 11 aircraft 31 First presentation part 32 Second presentation part 33 Hochi Department 51 Driver's seat 52 Steering 53 Dashboard 56 Rear differential lock operating mechanism 57 Front differential lock operating mechanism 112 Rear wheel 131 Rear differential lock device 132 Front differential lock device M1 display mark

Claims

1. An aircraft having a pair of rear wheels, The driver's seat and, A rear differential lock device that limits the differential movement of the pair of rear wheels, It comprises a rear differential lock operating unit that receives an operation to activate the rear differential lock device, The rear differential lock operating unit is located in front of the driver's seat. Work vehicle.

2. The dashboard is further located in front of the driver's seat, The rear differential lock operating unit is located on the dashboard. The work vehicle according to claim 1.

3. It is positioned in a location corresponding to the rear differential lock operating section and further includes an indicator mark representing the function of the rear differential lock operating section. A work vehicle according to claim 1 or 2.

4. The steering wheel is further located in front of the driver's seat, In a side view, the rear differential lock operating part is positioned higher than the lower end of the steering wheel. A work vehicle according to claim 1 or 2.

5. The system further includes a first display unit that displays the operating status of the rear differential lock device. A work vehicle according to claim 1 or 2.

6. The rear differential lock device is activated when the rear differential lock operating unit is operated while the activation conditions are met. The system further includes a notification unit that provides notification if the rear differential lock operating unit is operated while the aforementioned activation conditions are not met. A work vehicle according to claim 1 or 2.

7. The rear differential lock device is activated when the rear differential lock operating unit is operated while the activation conditions are met. The system further includes a second display unit that indicates whether or not the aforementioned activation conditions are met. A work vehicle according to claim 1 or 2.

8. The system further comprises a pair of brake devices for braking each of the aforementioned pair of rear wheels, The rear differential lock device is activated when the rear differential lock operating unit is operated while the activation conditions are met. The activation condition includes the fact that the pair of brake devices are in a brake-linked state in which they are linked together. A work vehicle according to claim 1 or 2.

9. A front differential lock device that limits the differential of the pair of front wheels of the aforementioned aircraft, The system further includes a front differential lock operating unit that receives an operation to activate the front differential lock device, A work vehicle according to claim 1 or 2.

10. The rear differential lock operating unit and the front differential lock operating unit are arranged side by side in front of the driver's seat. The work vehicle according to claim 9.

11. The rear differential lock device is activated when the rear differential lock operating unit is operated while the rear activation conditions are met. The front differential lock device is activated when the front differential lock operating unit is operated while the conditions for activation of the front differential are met. The rear activation conditions and the front activation conditions can be set individually. The work vehicle according to claim 9.

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