Work vehicle

Abstract

Provided is a work vehicle capable of preventing interference between a plurality of operation mechanisms capable of actuating a brake mechanism.　The present invention comprises: a brake lever 610 capable of actuating a brake mechanism by being operated in a predetermined direction; a first operation mechanism 620 that connects the brake lever 610 and a brake pedal 22 that an occupant can operate, said first operation mechanism 620 being capable of operating the brake lever 610 in accordance with the operation of the brake pedal 22; a second operation mechanism 650 that connects an electric cylinder 640 and the brake lever 610, and that can operate the brake lever 610 in accordance with the action of an electric actuator; and long holes 611a, 623b and pins 623c, 653c that, in accordance with the action of one of the first operation mechanism 620 and the second operation mechanism 650, prevent action by the other of the first operation mechanism 620 and the second operation mechanism 650.

Description

Work vehicles

[0001] The present invention relates to work vehicle technology.

[0002] 2. Description of the Related Art Conventionally, technology for a work vehicle equipped with a brake mechanism for braking wheels has been publicly known, as described in, for example, Japanese Patent Application Laid-Open No. 2003-222999.

[0003] In the tractor described in Patent Document 1, the brake mechanism is activated by operating an operating arm. The operating arm is connected to a brake pedal that can be depressed by a rider. The brake pedal is also connected to an electric actuator, and can be operated by transmitting the driving force of the electric actuator.

[0004] The tractor described in Patent Document 1 is configured to be capable of autonomous driving. When the tractor is autonomously driving, an electric actuator can be operated to operate the brake pedal. This allows the tractor to operate an operating arm to activate the brake mechanism and bring it to an emergency stop.

[0005] However, the tractor of Patent Document 1 is difficult to use because the brake pedal remains depressed even after an emergency stop is made.

[0006] Japanese Patent Application Laid-Open No. 2019-202613

[0007] One aspect of the present disclosure has been made in consideration of the above-described situation, and the problem it aims to solve is to provide a work vehicle that is capable of preventing interference between multiple operating mechanisms that can activate the brake mechanism.

[0008] The problem to be solved by one embodiment of the present disclosure has been described above, and next, the means for solving this problem will be described.

[0009] In one aspect of the present disclosure, a vehicle includes a brake lever that can be operated in a predetermined direction to activate a brake mechanism, a manual operation mechanism that connects a brake operating device that can be operated by a rider to the brake lever and that can operate the brake lever in conjunction with operation of the brake operating device, an electric operation mechanism that connects an electric actuator to the brake lever and that can operate the brake lever in conjunction with operation of the electric actuator, and an independence mechanism that prevents operation of either the manual operation mechanism or the electric operation mechanism in conjunction with operation of the other of the manual operation mechanism or the electric operation mechanism. According to one aspect of the present disclosure, interference between multiple operation mechanisms that can activate the brake mechanism can be prevented.

[0010] In one aspect of the present disclosure, the manual operation mechanism and the electric operation mechanism are connected in parallel to the brake lever, respectively. According to this aspect of the present disclosure, interference between the manual operation mechanism and the electric operation mechanism connected in parallel to the brake lever can be prevented.

[0011] In one aspect of the present disclosure, the independent mechanism includes a manual side elongated hole formed in either a first manual side member that operates in conjunction with the brake operating device or a second manual side member that operates in conjunction with the brake lever, and a manual side coupling part that is provided in the other of the first manual side member or the second manual side member and inserted into the manual side elongated hole. According to one aspect of the present disclosure, interference between multiple operating mechanisms can be prevented with a simple configuration.

[0012] In one aspect of the present disclosure, the independent mechanism includes an electric-side elongated hole formed in either one of an electric-side first member that operates in conjunction with the electric actuator or an electric-side second member that operates in conjunction with the brake lever, and an electric-side insertion part that is provided in the other of the electric-side first member or the electric-side second member and inserted into the electric-side elongated hole. According to one aspect of the present disclosure, interference between multiple operating mechanisms can be prevented with a simple configuration.

[0013] In one aspect of the present disclosure, the independent mechanism includes a manual-side elongated hole formed in either a first manual-side member that operates in conjunction with the brake operating device or a second manual-side member that operates in conjunction with the brake lever, a manual-side coupling part provided on the other of the first manual-side member or the second manual-side member and inserted into the manual-side elongated hole, an electric-side elongated hole formed in either a first electric-side member that operates in conjunction with the electric actuator or a second electric-side member that operates in conjunction with the brake lever, and an electric-side insertion part provided on the other of the first electric-side member or the second electric-side member and inserted into the electric-side elongated hole. According to one aspect of the present disclosure, interference between multiple operating mechanisms can be prevented with a simple configuration.

[0014] In one aspect of the present disclosure, a pair of left and right brake levers are provided corresponding to a pair of left and right brake mechanisms for braking the left and right wheels, respectively, and the electric operation mechanism connects the single electric actuator to the pair of left and right brake levers. According to one aspect of the present disclosure, the pair of left and right brake mechanisms can be operated collectively by the single electric actuator.

[0015] In one aspect of the present disclosure, the electric operation mechanism includes a rotating member that can rotate around a rotation axis in response to the driving force of the electric actuator, and a distributor that distributes and transmits the driving force of the electric actuator transmitted via the rotating member to the pair of left and right brake levers. According to one aspect of the present disclosure, by appropriately setting the shape of the rotating member, it is possible to adjust the operating force and operating speed of the brake levers by the electric actuator.

[0016] In one aspect of the present disclosure, the electric actuator includes an extendable rod, and the axial direction of the rotation shaft is oriented in a direction perpendicular to the extension direction of the rod. According to one aspect of the present disclosure, the electric actuator and the rotating member can be directly connected without providing a mechanism for converting the direction of transmission of the driving force, thereby simplifying the configuration.

[0017] In one aspect of the present disclosure, a pair of left and right brake levers are provided corresponding to the brake mechanisms of the left and right wheels, respectively, and two electric operation mechanisms are provided corresponding to the pair of left and right brake levers. According to one aspect of the present disclosure, by independently controlling the left and right electric actuators, the electric operation mechanism can be used as a single brake mechanism when turning the work vehicle.

[0018] According to one aspect of the present disclosure, it is possible to prevent interference between a plurality of operating mechanisms capable of actuating a brake mechanism.

[0019] FIG. 1 is a side view of a tractor according to an embodiment of the present invention. FIG. 2 is a side view of a first operating mechanism and a second operating mechanism. FIG. 3 is a plan view of the same. FIG. 4 is a perspective view of the second operating mechanism. FIG. 5 is a side view of the same. FIG. 6 is a plan view of the same. FIG. 7 is a side view of a cover member. FIG. 8 is a side sectional view of the second operating mechanism. FIG. 9 is a side view of a state in which the brake pedal is depressed. FIG. 10 is a side view of a state in which the rod of the electric cylinder is extended. FIG. 11 is a side sectional view of a state in which the attachment position of the wire is adjusted. FIG. 12 is a side view of a modified example of the second operating mechanism.

[0020] In the following description, the directions indicated by arrows U, D, F, B, L, and R in the figures are defined as upward, downward, forward, backward, leftward, and rightward, respectively.

[0021] First, the overall configuration of a tractor 1 according to an embodiment of the present disclosure will be described.

[0022] The tractor 1 shown in FIG. 1 mainly comprises a machine frame 2, an engine 3, a hood 4, a transmission case 5, front wheels 6, rear wheels 7, fenders 8, a lifting device 9, a cabin 10, a seat 20, a steering wheel 21, and the like.

[0023] The body frame 2 is a frame-shaped member formed by appropriately combining a plurality of plate materials. The body frame 2 is formed in a generally rectangular shape in a plan view. The body frame 2 is disposed at the front of the tractor 1 with its longitudinal direction facing the front-to-rear direction. An engine 3 is fixed to the rear of the body frame 2. The engine 3 is covered by a hood 4. A transmission case 5 is fixed to the rear of the engine 3. A muffler 4a that discharges exhaust gas from the engine 3 is disposed on the right side of the hood 4. In addition, a work light and a headlight are provided on the front of the hood 4. The work light and the headlight are provided on both the left and right sides of the front of the hood 4, spaced apart in the left-to-right direction.

[0024] The front portion of the vehicle frame 2 is supported by a pair of left and right front wheels 6 via a front axle mechanism (not shown). The rear portion of the transmission case 5 is supported by a pair of left and right rear wheels 7 via a rear axle mechanism (not shown). The pair of left and right rear wheels 7 are generally covered from above by fenders 8.

[0025] A lifting device 9 is provided at the rear of the transmission case 5. Various types of implements (e.g., a tiller) can be attached to the lifting device 9. The lifting device 9 can raise and lower the attached implements using an actuator such as a hydraulic cylinder. Power from the engine 3 can be transmitted to the lifting device 9 via a PTO shaft (not shown).

[0026] The power of the engine 3 is changed in speed by a transmission (not shown) housed in a transmission case 5, and then can be transmitted to front wheels 6 via the front axle mechanism, and to rear wheels 7 via the rear axle mechanism. The front wheels 6 and rear wheels 7 are driven to rotate by the power of the engine 3, allowing the tractor 1 to travel. The power of the engine 3 can also be used to drive a work device attached to the lifting device 9.

[0027] A cabin 10 is provided behind the engine 3. The cabin 10 is mounted on the vehicle body (transmission case 5, etc.). Inside the cabin 10, a living space for a driver is formed.

[0028] As shown in Figure 1, a seat 20 for a driver to sit in is disposed approximately in the center of the cabin 10. The cabin 10 is also provided with an auxiliary step 20a for getting in and out of the seat 20. The auxiliary step 20a is provided on at least the left side of the cabin 10. The auxiliary step 20a can also be provided on both sides of the cabin 10. A steering wheel 21 for adjusting the turning angle of the front wheels 6 is also disposed in the front of the cabin 10.

[0029] A brake pedal 22 for braking is disposed below the steering wheel 21. By depressing the brake pedal 22, the occupant can apply braking force to the left and right wheels (e.g., the rear wheels 7) according to the amount of operation of the brake pedal 22.

[0030] The cabin 10 is also provided with a parking brake operating unit (not shown) that can be operated by a passenger. The parking brake operating unit is configured, for example, with a switch. By operating the parking brake operating unit, the passenger can switch between a braking state in which braking force is applied to the left and right wheels and a brake release state in which no braking force is applied. A fuel tank 23 is also disposed below the cabin 10.

[0031] The tractor 1 of this embodiment can detect the position of the vehicle body (position information including latitude and longitude) using a GPS or the like, and can execute control to automatically steer the vehicle body based on the position information. Examples of the control include control to automatically steer the vehicle body so that it travels straight and parallel to a predetermined travel reference line, and control to automatically travel the vehicle body along a created target travel route. The tractor 1 can also brake the wheels during automatic travel.

[0032] The following describes the configuration related to the brake of the tractor 1. Specifically, the following describes the brake pedal 22, brake lever 610, first operating mechanism 620, support member 630, electric cylinder 640, second operating mechanism 650, adjustment mechanism 660, and cover member 670. Note that illustration of the cover member 670 is omitted in the drawings other than Figures 1 and 7.

[0033] 2 and 3 are provided as a pair of left and right brake pedals 22. The pair of left and right brake pedals 22 are configured to be able to swing in the front-rear direction around a swing shaft 22a whose axis direction is oriented in the left-right direction. The pair of left and right brake pedals 22 are biased rearward by a return spring (not shown). A passenger can operate the pair of left and right brake pedals 22 by depressing them individually.

[0034] The brake lever 610 operates a pair of brake mechanisms B (see FIG. 1) on the left and right sides to brake the left and right wheels, respectively. The brake mechanisms B can brake the wheels, for example, by pressing brake pads against brake discs that rotate integrally with the wheels. Note that the brake mechanisms B are not limited to the above-described configuration as long as they are capable of braking the wheels.

[0035] A pair of left and right brake levers 610 are provided corresponding to the pair of left and right brake mechanisms B. The left brake lever 610 can operate the left brake mechanism B. The right brake lever 610 can operate the right brake mechanism B. As shown in FIG. 2 , the pair of left and right brake levers 610 includes a lever body 611 and an operating shaft 612.

[0036] The lever body 611 is formed in a plate shape with its plate surface facing in the left-right direction. An elongated hole 611a is formed in the lever body 611. The elongated hole 611a penetrates the lever body 611 in the left-right direction. The elongated hole 611a is formed in a generally arc shape in a side view with the operating shaft 612 as its center.

[0037] The actuating shaft 612 is disposed with its axis oriented in the left-right direction. The actuating shaft 612 is rotatably supported on the vehicle body. The upper end of the lever body 611 is fixed to the actuating shaft 612.

[0038] The lever body 611 can swing back and forth around the operating shaft 612. When the lever body 611 swings forward, the operating shaft 612 rotates, and the pair of left and right brake levers 610 can operate the pair of left and right brake mechanisms B to brake the wheels. The lever body 611 is biased rearward by a biasing member.

[0039] The first operating mechanism 620 is used to operate the brake lever 610 in conjunction with operation of the brake pedal 22. A pair of first operating mechanisms 620 is provided, one on the left and one on the right (see FIG. 3 ). The left first operating mechanism 620 connects the left brake pedal 22 and the left brake lever 610. The right first operating mechanism 620 connects the right brake pedal 22 and the right brake lever 610. The configuration of the first operating mechanisms 620 will be described below using the left first operating mechanism 620 as an example. As shown in FIG. 2 , the first operating mechanism 620 includes a first brake rod 621, a link mechanism 622, a second brake rod 623, and a hydraulic cylinder 624.

[0040] The first brake rod 621 is a shaft-shaped member whose longitudinal direction is oriented in the vertical direction. The upper end of the first brake rod 621 is connected to the brake pedal 22.

[0041] The link mechanism 622 connects the first brake rod 621 and the second brake rod 623. The link mechanism 622 includes a swing shaft 622a, a first link member 622b, and a second link member 622c. The swing shaft 622a is disposed with its axis oriented in the left-right direction. The first link member 622b and the second link member 622c are swingably supported by the swing shaft 622a. The lower end of the first brake rod 621 is connected to the first link member 622b.

[0042] The second brake rod 623 is an axial member with its longitudinal direction oriented in the front-to-rear direction. The front end of the second brake rod 623 is connected to the second link member 622c. More specifically, an attachment portion 623a with its plate surface facing left and right is formed at the front end of the second brake rod 623. A pin 623c is inserted into an elongated hole 623b formed in the attachment portion 623a and into the second link member 622c, thereby connecting the front end of the second brake rod 623 to the second link member 622c. The elongated hole 623b is formed in a straight line extending along the axial direction of the second brake rod 623.

[0043] The hydraulic cylinder 624 is for automatically operating the brake mechanism B when the tractor 1 turns, etc. The hydraulic cylinder 624 is arranged so that the rod 624a faces forward. The rear end of the second brake rod 623 is connected to the rod 624a of the hydraulic cylinder 624. The lever body 611 of the brake lever 610 is connected to the rear end of the hydraulic cylinder 624.

[0044] The first operating mechanism 620 transmits the operating force of the brake pedal 22 to the brake lever 610 in response to depression of the brake pedal 22. Specifically, as shown in Fig. 9, when the brake pedal 22 is depressed, the brake pedal 22 swings around the swing shaft 22a. As the brake pedal 22 swings, the first link member 622b is pulled upward via the first brake rod 621, and the second brake rod 623 is pulled forward via the second link member 622c.

[0045] This causes the brake lever 610 to swing forward, causing the operating shaft 612 to rotate, and actuating the brake mechanism B. In this way, the rider can apply a braking force to the wheels according to the amount of depression of the brake pedal 22.

[0046] Furthermore, when the tractor 1 turns, the hydraulic cylinder 624 is controlled to brake the wheel located on the inside of the turning trajectory. For example, when the tractor 1 turns left, the rod 624a of the left hydraulic cylinder 624 is contracted and the left brake lever 610 is swung forward. This brakes the left wheel, making it possible to reduce the turning radius of the tractor 1. In this way, the hydraulic cylinder 624 is used as a one-side brake mechanism that brakes one of the left or right wheels.

[0047] The support member 630 shown in Figures 4 and 5 is for supporting the electric cylinder 640 and the like. The support member 630 is formed in a generally plate-like shape with its plate surface facing in the left-right direction. The support member 630 includes a first member 631 and a second member 632. The first member 631 is fixed to the vehicle frame 2. The second member 632 is disposed rearward of the first member 631 and fixed to the transmission case 5.

[0048] The electric cylinder 640 is used to operate the pair of left and right brake levers 610. The electric cylinder 640 is supported by the first member 631. The electric cylinder 640 is arranged so that the rod 641 faces rearward. In this embodiment, one electric cylinder 640 is provided for each pair of left and right brake levers 610 (see FIG. 3). The electric cylinder 640 is configured to be operable by power supply from a power source (for example, a battery in the hood 4). An operation signal corresponding to the operation of the parking brake operation unit described above and a control signal for when the tractor 1 is traveling autonomously are input to the electric cylinder 640. The electric cylinder 640 can extend and retract the rod 641 in response to these signals.

[0049] The second operating mechanism 650 is for operating the brake lever 610 in accordance with the extension and contraction of the rod 641. The second operating mechanism 650 connects one electric cylinder 640 to the pair of left and right brake levers 610. The second operating mechanism 650 includes a link mechanism 651, an equalizer 652, and wires 653U and 653D.

[0050] The link mechanism 651 is for connecting the electric cylinder 640 and the equalizer 652. The link mechanism 651 includes a rotary shaft 651a, a first link member 651b, and a second link member 651c.

[0051] The rotation shaft 651a is disposed with its axis directed in the left-right direction (a direction perpendicular to the extension / contraction direction of the rod 641). The rotation shaft 651a is supported by the second member 632 of the support member 630.

[0052] The first link member 651b is formed in a plate shape with its plate surface facing in the left-right direction and is rotatably supported on the rotation shaft 651a. As shown in Figure 8, the first link member 651b has a first extending portion 651d and a second extending portion 651e.

[0053] The first extending portion 651d is formed to extend downward from the rotation shaft 651a in side view. The rod 641 of the electric cylinder 640 is connected to the tip end (lower end) of the first extending portion 651d. The second extending portion 651e is formed to extend upward from the rotation shaft 651a in side view.

[0054] 4 and 5 is formed in a plate shape with its plate surface facing left and right and is rotatably supported on the rotation shaft 651a. The second link member 651c is formed in the same shape as the second extension portion 651e (see FIG. 8) of the first link member 651b. The second link member 651c is located to the left of the second extension portion 651e.

[0055] The equalizer 652 distributes and transmits the thrust of the electric cylinder 640 to the pair of left and right brake levers 610. The equalizer 652 is disposed between the front wheel 6 and the rear wheel 7 shown in FIG. 1 in the front-to-rear direction. The equalizer 652 is also disposed forward of the fuel tank 23. As shown in FIG. 8, the equalizer 652 includes a main body 652a, a first connecting shaft 652b, and a second connecting shaft 652c.

[0056] The main body portion 652a is formed in a plate shape with its plate surface facing in the left-right direction. A pair of main body portions 652a are provided, one on the left and one on the right. The main body portion 652a is disposed between the first link member 651b and the second link member 651c in the left-right direction (see FIGS. 4 and 6). The main body portion 652a, the first link member 651b, and the second link member 651c are connected to one another by a pin 652d. The main body portion 652a, the first link member 651b, and the second link member 651c can rotate about the rotation shaft 651a in response to the extension and contraction of the rod 641 of the electric cylinder 640. The main body portion 652a can also rotate relative to the first link member 651b, etc., about the pin 652d.

[0057] The first connecting shaft 652b is a portion to which the upper wire 653U is connected. The first connecting shaft 652b is disposed with its axis oriented in the left-right direction. The first connecting shaft 652b is supported by the pair of left and right main body portions 652a.

[0058] The second connecting shaft 652c is a portion to which the lower wire 653D is connected. The second connecting shaft 652c is disposed with its axis oriented in the left-right direction. The second connecting shaft 652c is supported by the pair of left and right main body portions 652a. The second connecting shaft 652c is disposed below the first connecting shaft 652b.

[0059] The wires 653U and 653D shown in Figures 2, 3, and 8 are used to transmit the thrust of the electric cylinder 640 to the pair of left and right brake levers 610. The wires 653U and 653D connect the equalizer 652 to the pair of left and right brake levers 610. As shown in Figure 8, the wires 653U and 653D have male thread portions 653a. The male thread portions 653a are formed on the front ends of the wires 653U and 653D. The male thread portion 653a of the wire 653U is inserted into the first connecting shaft 652b. The male thread portion 653a of the wire 653D is inserted into the second connecting shaft 652c. By fastening a nut 662 or the like of the adjustment mechanism 660 (described later) to the male thread portion 653 a, the front ends of the wires 653 U and 653 D are connected to the first connecting shaft 652 b and the second connecting shaft 652 c of the equalizer 652 .

[0060] 2 and 3 , the rear ends of the wires 653U and 653D are connected to the lever bodies 611 of the pair of left and right brake levers 610. More specifically, attachment portions 653b with plate surfaces facing left and right are formed at the rear ends of the wires 653U and 653D, and a pin 653c is inserted into the attachment portion 653b and an elongated hole 611a of the lever body 611, thereby connecting the rear ends of the wires 653U and 653D to the lever body 611. In this embodiment, the upper wire 653U is connected to the right lever body 611, and the lower wire 653D is connected to the left lever body 611.

[0061] In this way, the first operating mechanism 620 and the second operating mechanism 650 are each connected in parallel to the brake lever 610. More specifically, the first operating mechanism 620 and the second operating mechanism 650 are connected directly to the brake lever 610 without any intervening member (common member) therebetween.

[0062] 8 is for adjusting the attachment positions of the wires 653U and 653D relative to the equalizer 652. The adjustment mechanism 660 is provided on the equalizer 652. The adjustment mechanism 660 includes a high nut 661 and a nut 662.

[0063] The high nuts 661 are used to adjust the mounting positions of the wires 653U and 653D. The high nuts 661 are threaded onto the male threaded portions 653a of the wires 653U and 653D, respectively. The high nuts 661 are pulled rearward by the wires 653U and 653D and abut against the first connecting shaft 652b and the second connecting shaft 652c via the washers 661a. In this way, the high nuts 661 are held (attached) to the first connecting shaft 652b and the second connecting shaft 652c. The high nuts 661 are positioned so as to protrude forward from the outer edge of the main body 652a of the equalizer 652.

[0064] The nut 662 is used to fix the high nut 661. The nut 662 is threaded onto the male thread portion 653a and is disposed in front of the high nut 661.

[0065] The cover member 670 shown in Figure 7 is a plate-like member that covers the electric cylinder 640, link mechanism 651, equalizer 652, and adjustment mechanism 660. The cover member 670 is formed in a roughly box shape that is open on the right. The cover member 670 includes a side plate portion 671 that covers the left side of the electric cylinder 640 etc., a bottom portion 672 that covers the lower portion, a top portion 673 that covers the upper portion, a front plate portion 674 that covers the front, and a rear plate portion 675 that covers the rear. The rear plate portion 675 is formed with cutout portions 675a ​​through which the wires 653U and 653D can be inserted.

[0066] The cover member 670 is fixed to the support member 630 (see FIG. 5) by fixing members such as bolts. By covering the electric cylinder 640 and the like with the cover member 670 in this way, it is possible to prevent mud and the like from adhering to the electric cylinder 640 and the like.

[0067] The following describes the operation of the second operating mechanism 650. The following also describes the operation of the second operating mechanism 650 using an example in which the rod 641 shown in Figures 2 and 5 is extended. Figures 2 and 5 show the second operating mechanism 650 in a state in which the brake lever 610 is swung rearward and the wheel is not braked (brake-released state).

[0068] 2 and 5 is extended, the first link member 651b, the second link member 651c, and the main body 652a of the equalizer 652 rotate about the rotation shaft 651a, thereby pulling the wires 653U and 653D forward, and the thrust of the electric cylinder 640 is distributed to the wires 653U and 653D.

[0069] 10, when the wires 653U and 653D are pulled, the pair of left and right brake levers 610 are swung forward, the operating shaft 612 is rotated, and the pair of left and right brake mechanisms B are actuated. This makes it possible to switch to a braking state in which braking force is applied to the left and right wheels.

[0070] When the rod 641 of the electric cylinder 640 is contracted, the second operating mechanism 650 operates in the opposite manner to when the rod 641 is extended. This allows the second operating mechanism 650 to swing the brake lever 610 rearward, thereby switching to a brake release state in which the application of braking force to the wheel is released.

[0071] In this embodiment, as shown in an enlarged view in FIG. 10 , the second brake rod 623 is connected to the second link member 622c via a long hole 623b and a pin 623c formed in the second brake rod 623. Therefore, when the pair of left and right brake levers 610 are swung forward by operation of the electric cylinder 640, the second brake rod 623 is moved forward. However, because the pin 623c inserted into the second link member 622c slides within the long hole 623b of the second brake rod 623, it is possible to prevent the second link member 622c from rotating in accordance with the movement of the second brake rod 623. In this way, it is possible to suppress transmission of thrust from the electric cylinder 640 to the brake pedal 22.

[0072] 9, the wires 653U and 653D are connected to the brake lever 610 via a long hole 611a and a pin 653c formed in the lever body 611. Therefore, when the brake pedal 22 is depressed, the brake lever 610 is swung forward. However, the pin 653c inserted into the wires 653U and 653D slides within the long hole 611a of the brake lever 610, preventing the wires 653U and 653D from moving forward as the brake lever 610 moves. In this way, the operating force of the brake pedal 22 can be prevented from being transmitted to the electric cylinder 640.

[0073] As described above, in this embodiment, the elongated hole 611a and the pin 653c block the transmission of power from the first operation mechanism 620 to the second operation mechanism 650 (see FIG. 9), and the elongated hole 623b and the pin 623c block the transmission of power from the second operation mechanism 650 to the first operation mechanism 620 (see FIG. 10). The elongated holes 611a and 623b and the pins 623c and 653c are independent mechanisms that enable the first operation mechanism 620 and the second operation mechanism 650 to operate independently of each other.

[0074] By providing an independent mechanism in this manner, usability can be improved. For example, the brake pedal 22 can be depressed in the braking state shown in FIG. 10 (a state in which braking force is applied to the wheels by operating the parking brake operating unit, etc.). Therefore, by releasing the braking state by the electric cylinder 640 while depressing the brake pedal 22, the rider can use the brake pedal 22 to brake the wheels even after the braking state is released. This makes it possible to prevent the tractor 1 from moving unintentionally by the rider.

[0075] In this embodiment, when the parking brake operating unit is operated, the electric cylinder 640 operates instead of the hydraulic cylinder 624. This allows the wheels to be braked even when the engine 3 is not running.

[0076] 5, in this embodiment, the rod 641 of the electric cylinder 640 is not directly connected to the equalizer 652, but is connected to the equalizer 652 via a rotatable first link member 651b or the like. This makes it possible to adjust the operating force and operating speed of the brake lever 610 that accompany the extension and contraction of the electric cylinder 640. For example, by making the distance from the rotation shaft 651a to the rod 641 relatively long, the operating force of the brake lever 610 can be increased. Furthermore, for example, by making the distance from the rotation shaft 651a to the rod 641 relatively short, the operating speed of the brake lever 610 can be increased.

[0077] Here, differences may occur in the pull lengths of the wires 653U and 653D due to changes in the state of the pair of left and right brake mechanisms B. For example, if the right brake mechanism B (brake disc, etc.) is more worn than the left, the pull length of the upper wire 653U connected to the right brake mechanism B may become larger than that of the lower wire 653D.

[0078] If there is a difference in the pull lengths of the wires 653U and 653D, the main body 652a of the equalizer 652 rotates around the pin 652d. For example, if the pull length of the upper wire 653U is greater than that of the lower wire 653D, the equalizer 652 rotates counterclockwise as viewed from the left side around the pin 652d. This absorbs the difference in the pull lengths of the wires 653U and 653D and enables equal braking force to be applied to the left and right wheels.

[0079] In this embodiment, the difference in the pulling allowance between the wires 653U and 653D can be adjusted by using the adjustment mechanism 660. Specifically, when the nut 662 of the adjustment mechanism 660 shown in FIG. 11 is loosened, the fixation of the high nut 661 is released.

[0080] In this state, the rider can rotate the high nut 661 to move the male threaded portions 653a of the wires 653U and 653D forward or backward relative to the first connecting shaft 652b and the second connecting shaft 652c. Furthermore, by fastening the nut 662 at a predetermined forward or backward position, the wires 653U and 653D can be fixed at that forward or backward position. This allows the adjustment mechanism 660 to change the connection positions of the male threaded portions 653a with respect to the first connecting shaft 652b and the second connecting shaft 652c (the attachment positions of the wires 653U and 653D with respect to the equalizer 652).

[0081] If the pull length of the upper wire 653U becomes larger than that of the lower wire 653D, the pull length of the upper wire 653U can be reduced by moving the upper male screw portion 653a forward using the procedure described above.

[0082] Furthermore, the adjustment mechanism 660 is provided in the equalizer 652. With this configuration, the installation space of the equalizer 652 can be utilized to install the adjustment mechanism 660, thereby saving space. Furthermore, adjustment of the wires 653U and 653D and maintenance of the equalizer 652 can be performed in the same location, improving maintainability.

[0083] The equalizer 652 is attached to the support member 630 via a link mechanism 651. By attaching the electric cylinder 640, the link mechanism 651, and the equalizer 652 to a common member (the support member 630) in this way, the electric cylinder 640 and the equalizer 652 can be assembled to the vehicle body while attached to the support member 630, thereby improving the workability of the assembly work.

[0084] As described above, the tractor 1 (work vehicle) according to this embodiment is equipped with a brake lever 610 that can be operated in a predetermined direction to activate the brake mechanism B, a first operation mechanism 620 (manual operation mechanism) that connects the brake lever 610 to a brake pedal 22 (brake operation device) that can be operated by a rider, and that can operate the brake lever 610 in conjunction with operation of the brake pedal 22, a second operation mechanism 650 (electric operation mechanism) that connects an electric cylinder 640 (electric actuator) to the brake lever 610, and that can operate the brake lever 610 in conjunction with operation of the electric cylinder 640, and an independent mechanism (long holes 611a and 623b and pins 623c and 653c) that prevents operation of either the first operation mechanism 620 or the second operation mechanism 650 in conjunction with operation of the other one of the first operation mechanism 620 and the second operation mechanism 650 (see Figures 2, 9 and 10).

[0085] By configuring in this manner, interference between the operating mechanisms can be prevented in a tractor 1 having multiple operating mechanisms (first operating mechanism 620 and second operating mechanism 650) that can activate the brake mechanism B.

[0086] The first operating mechanism 620 and the second operating mechanism 650 are connected in parallel to the brake lever 610 .

[0087] With this configuration, interference between the first operating mechanism 620 and the second operating mechanism 650 connected in parallel to the brake lever 610 can be prevented.

[0088] The independent mechanism also includes a long hole 623b (manual side long hole) formed in either one of the second link member 622c (manual side first member) that operates in conjunction with the brake pedal 22 or the second brake rod 623 (manual side second member) that operates in conjunction with the brake lever 610, and a pin 623c (manual side connecting portion) that is provided in the other of the second link member 622c or the second brake rod 623 and inserted into the long hole 623b (see Figures 2 and 10).

[0089] With this configuration, interference between multiple operating mechanisms can be prevented with a simple configuration (long holes 623b).

[0090] The independent mechanism also includes a long hole 611a (electric side long hole) formed in either one of the wires 653U and 653D (electric side first member) that operate in conjunction with the electric cylinder 640 or the lever body 611 (electric side second member) that operates in conjunction with the brake lever 610, and a pin 653c (electric side insertion portion) that is provided in the other of the wires 653U and 653D or the lever body 611 and inserted into the long hole 611a (see Figures 2 and 9).

[0091] With this configuration, interference between multiple operating mechanisms can be prevented with a simple configuration (long holes 611a).

[0092] The independent mechanism also includes an elongated hole 623b formed in either one of a second link member 622c that operates in conjunction with the brake operating device or a second brake rod 623 that operates in conjunction with the brake lever 610, a pin 623c provided on the other of the second link member 622c or the second brake rod 623 and inserted into the elongated hole 623b, an elongated hole 611a formed in either one of wires 653U and 653D that operate in conjunction with the electric cylinder 640 or a lever main body 611 that operates in conjunction with the brake lever 610, and a pin 653c provided on the other of the wires 653U and 653D or the lever main body 611 and inserted into the elongated hole 611a (see Figures 2, 9 and 10).

[0093] With this configuration, interference between multiple operating mechanisms can be prevented with a simple configuration (long holes 611a).

[0094] In addition, the brake levers 610 are provided in pairs on the left and right to correspond to a pair of left and right brake mechanisms B for braking the left and right wheels, respectively, and the second operating mechanism 650 connects one electric cylinder 640 and the pair of left and right brake levers 610 (see Figure 3).

[0095] With this configuration, the pair of left and right brake mechanisms B can be operated simultaneously by one electric cylinder 640.

[0096] The second operating mechanism 650 also includes a first link member 651b and a second link member 651c (rotating members) that can rotate around a rotation axis 651a in accordance with the driving force of the electric cylinder 640, and an equalizer 652 (distribution unit) that distributes and transmits the driving force (thrust) of the electric cylinder 640 transmitted via the first link member 651b and the second link member 651c to the pair of left and right brake levers 610 (see Figures 2 and 10).

[0097] By configuring it in this manner, the operating force and operating speed of the brake lever 610 by the electric cylinder 640 can be adjusted by appropriately setting the shapes of the first link member 651b and the second link member 651c (such as the dimensions from the center of rotation to the connection part with the electric cylinder 640 and the equalizer 652).

[0098] The electric cylinder 640 is provided with an extendable rod 641, and the axial direction (left-right direction) of the rotation shaft 651a is oriented perpendicular to the extension and contraction direction (front-back direction) of the rod 641 (see Figure 11).

[0099] By configuring in this manner, the electric cylinder 640 (rod 641) can be directly connected to the first link member 651b, etc. without providing a mechanism for changing the direction of transmission of the driving force, thereby simplifying the configuration.

[0100] As described above, the tractor 1 (work vehicle) according to this embodiment is equipped with an equalizer 652 (distribution unit) that distributes the driving force from the electric cylinder 640 (driving source) and transmits it to a plurality of driving force transmission members (wires 653U and 653D), and an adjustment mechanism 660 that is provided on the equalizer 652 and that can adjust the mounting position of the driving force transmission members relative to the equalizer 652.

[0101] With this configuration, the equalizer 652 and the adjustment mechanism 660 can be installed in a common space, thereby saving space and improving maintainability.

[0102] The equalizer 652 also includes a first connecting shaft 652b and a second connecting shaft 652c (connecting portion) to which the driving force transmission members (wires 653U and 653D) are connected, and the adjustment mechanism 660 includes a high nut 661 (operating portion) that can change the connection position of the driving force transmission members relative to the first connecting shaft 652b and the second connecting shaft 652c by a predetermined operation (see FIG. 11).

[0103] By configuring in this way, it is possible to improve maintainability.

[0104] Furthermore, the high nut 661 can be rotated to change the connection positions of the driving force transmission members (wires 653U and 653D) with respect to the first connecting shaft 652b and the second connecting shaft 652c (see FIG. 11).

[0105] This configuration allows the connection position to be adjusted with a simple operation, improving maintainability.

[0106] In addition, the driving force transmission member is composed of wires 653U and 653D, and the high nut 661 is attached to the wires 653U and 653D that are inserted through the first connecting shaft 652b and the second connecting shaft 652c. By changing the axial mounting position of the wires 653U and 653D, the connection position of the wires 653U and 653D relative to the high nut 661 can be changed (see Figure 11).

[0107] By configuring it in this way, the adjustment mechanism 660 can be made to have a simple configuration.

[0108] The equalizer 652 supports the first connecting shaft 652b and the second connecting shaft 652c and includes a main body 652a that can swing around a swing shaft 622a, and the high nut 661 is arranged so as to protrude outward from the outer edge of the main body 652a (see Figure 11).

[0109] With this configuration, the main body 652a is less likely to get in the way when adjusting the mounting position, allowing the adjustment work to be carried out efficiently, thereby improving maintainability.

[0110] The driving source is an electric cylinder 640 (electric actuator), and the driving force transmission member (wires 653U and 653D) transmits the driving force distributed by the equalizer 652 to the brake mechanisms B of the left and right wheels (see Figures 2 and 3).

[0111] By configuring in this manner, the mechanism (second operating mechanism 650) that connects the electric cylinder 640 and the brake mechanism B can be made easier to maintain.

[0112] The tractor 1 further includes a cover member 670 that covers the equalizer 652 from at least one of the left and right sides (see FIG. 7).

[0113] This configuration can prevent mud and the like from adhering to the equalizer 652 and the adjustment mechanism 660.

[0114] The equalizer 652 is disposed between the front wheels 6 and the rear wheels 7 in the longitudinal direction.

[0115] By configuring it in this way, the front wheels 6 and the like are less likely to get in the way when adjusting the mounting position, and maintenance can be improved.

[0116] The equalizer 652 is disposed forward of the fuel tank 23 in the front-rear direction.

[0117] With this configuration, the fuel tank 23 is less likely to get in the way when adjusting the mounting position, and maintenance can be facilitated.

[0118] The tractor 1 according to this embodiment is an embodiment of a work vehicle. The brake pedal 22 according to this embodiment is an embodiment of a brake operating tool. The first operating mechanism 620 according to this embodiment is an embodiment of a manual operating mechanism. The electric cylinder 640 according to this embodiment is an embodiment of an electric actuator and a drive source. The second operating mechanism 650 according to this embodiment is an embodiment of an electric operating mechanism. The elongated holes 623b and 651a and the pins 623c and 653c according to this embodiment are an embodiment of an independent mechanism. The second link member 622c according to this embodiment is an embodiment of a manual-side first member. The second brake rod 623 according to this embodiment is an embodiment of a manual-side second member. The elongated hole 623b according to this embodiment is an embodiment of a manual-side elongated hole. The pin 623c according to this embodiment is an embodiment of a manual-side coupling portion. The wires 653U and 653D according to this embodiment are an embodiment of an electric motor-side first member and a driving force transmission member. The lever body 611 according to this embodiment is an embodiment of an electric motor-side second member. The elongated hole 611a according to this embodiment is an embodiment of an electric motor-side elongated hole. The pin 653c according to this embodiment is an embodiment of an electric motor-side coupling portion. The first link member 651b and the second link member 651c according to this embodiment are an embodiment of a rotating member. The equalizer 652 according to this embodiment is an embodiment of a distributor. The first coupling shaft 652b and the second coupling shaft 652c according to this embodiment are an embodiment of a coupling portion. The high nut 661 according to this embodiment is an embodiment of an operating portion.

[0119] Although the embodiment of the present invention has been described above, the present invention is not limited to the above configuration, and various modifications are possible within the scope of the invention described in the claims.

[0120] For example, although the work vehicle according to the present embodiment is a tractor 1, the type of work vehicle according to the present invention is not limited to this. The work vehicle according to the present invention may be other agricultural vehicles, construction vehicles, industrial vehicles, etc.

[0121] In addition, in this embodiment, the brake lever 610 is operated by the electric cylinder 640, but the type of electric actuator is not limited to the electric cylinder 640, and may be other equipment (such as an electric motor) that is driven by the supply of electricity.

[0122] In addition, in this embodiment, the elongated hole 623b is formed in the second brake rod 623 (see FIG. 2), but the member in which the elongated hole 623b is formed is not limited to the second brake rod 623. The elongated hole 623b may be formed in any member as long as it is formed in a path through which the operating force is transmitted from the brake pedal 22 to the brake lever 610. For example, the elongated hole 623b may be formed in the first brake rod 621, the second link member 622c, etc.

[0123] In this embodiment, the elongated hole 611a is formed in the lever body 611, but the member in which the elongated hole 611a is formed is not limited to the lever body 611. The elongated hole 611a may be formed in any part of the path through which thrust is transmitted from the electric cylinder 640 to the brake lever 610. For example, the elongated hole 611a may be formed in the attachment portion 653b of the wires 653U and 653D.

[0124] In addition, in this embodiment, the first operating mechanism 620 and the second operating mechanism 650 are configured to operate independently of each other by the long holes 623b and 611a and the pins 623c and 653c, but the configuration of the mechanism (independent mechanism) that operates each operating mechanism 620 and 650 independently is not limited to the long holes 623b and 611a and the pins 623c and 653c.

[0125] Furthermore, although the independent mechanism is configured from a part of the first operating mechanism 620 and the second operating mechanism 650 (long hole 623b, pin 653c, etc.), it can also be configured from a member separate from each operating mechanism 620, 660.

[0126] Furthermore, in this embodiment, one electric cylinder 640 is used to operate the pair of left and right brake levers 610, but the correspondence between the electric cylinder 640 and the brake levers 610 is not limited to this. For example, it is also possible to operate the pair of left and right brake levers 610 using left and right electric cylinders 640, respectively. An example of this configuration will be described below with reference to FIG. 12 .

[0127] The electric cylinders 640 shown in FIG. 12 are provided as a pair on the left and right to correspond to the pair of left and right brake levers 610. Although FIG. 12 only illustrates the left electric cylinder 640 and the left operating mechanism (first operating mechanism 620, etc.) of the pair of left and right electric cylinders 640, in reality, the right electric cylinder 640 and operating mechanism are disposed to the right of the left electric cylinder 640 (e.g., on the right side of the vehicle body). The configuration of the electric cylinders 640 will be described below using the left electric cylinder 640 as an example. The electric cylinder 640 is disposed so that the rod 641 faces rearward. A plate-shaped mounting portion 642a is formed at the tip of the rod 641. The mounting portion 642a is formed with a long hole 642b that is generally arc-shaped in side view and centered on the swing shaft 622a.

[0128] A pair of second operating mechanisms 750 are provided on the left and right, and connect the pair of left and right electric cylinders 640 and the pair of left and right link mechanisms 622. The second operating mechanisms 750 include a connecting member 751. The connecting member 751 is formed in a plate shape with its plate surface facing in the left-right direction, and is supported on the swing shaft 622a so as to be swingable. The first link member 622b, the second link member 622c, and the connecting member 751 are configured to be swingable integrally with each other.

[0129] Furthermore, the pin 752 is inserted through the connecting member 751 and the long hole 642b of the mounting portion 642a, thereby connecting the connecting member 751 and the rod 641 to each other. The long hole 642b may be formed in the connecting member 751 instead of the electric cylinder 640.

[0130] The first brake rod 621 is connected to a first link member 622b via an elongated hole 621b. In Fig. 12, the elongated hole 621b is formed in the mounting portion 621a of the first brake rod 621, and a pin 621c is inserted through the elongated hole 621b and the first link member 622b. Note that the elongated hole 621b may be formed in the first link member 622b instead of the first brake rod 621.

[0131] The second brake rod 623 is connected to the second link member 622c without passing through an elongated hole.

[0132] 12 , when the brake pedal 22 is operated, the second link member 622c can be swung in conjunction with the swinging of the first link member 622b. At this time, the pin 752 inserted in the connecting member 751 slides in the elongated hole 642b of the rod 641, thereby interrupting the transmission of power from the brake pedal 22 to the electric cylinder 640. Furthermore, when the rod 641 extends or retracts, the second link member 622c can be swung in conjunction with the swinging of the connecting member 751. At this time, the pin 621c inserted in the first link member 622b slides in the elongated hole 621b of the first brake rod 621, thereby interrupting the transmission of power from the electric cylinder 640 to the brake pedal 22.

[0133] In this way, even when a pair of left and right electric cylinders 640 are provided corresponding to a pair of left and right brake mechanisms B, the first operating mechanism 620 and the second operating mechanism 650 can be operated independently by the long holes 621b and 642b and the pins 621c and 752.

[0134] Furthermore, by individually controlling the left and right electric cylinders 640, they can also function as the hydraulic cylinder 624 of this embodiment (see FIG. 2). For example, when the tractor 1 turns left, the rod 641 of the left electric cylinder 640 is contracted, activating the left brake mechanism B. This brakes the left wheel, making it possible to reduce the turning radius of the tractor 1. With this configuration, the hydraulic cylinder 624 can be omitted.

[0135] As described above, the brake levers 610 are provided in pairs on the left and right to correspond to the brake mechanisms B of the left and right wheels, respectively, and two second operating mechanisms 650 are provided to correspond to the pair of left and right brake levers 610.

[0136] By configuring it in this manner, the second operating mechanism 650 can be used as a one-side brake mechanism when turning the tractor 1.

[0137] Furthermore, the adjustment mechanism 660 adjusts the mounting positions of the wires 653U and 653D using the high nuts 661 (see Figure 11), but it is also possible to adjust the mounting positions of the wires 653U and 653D using a member other than the high nuts 661.

[0138] Furthermore, the electric cylinder 640, the equalizer 652, and the wires 653U and 653D are used to operate the brake mechanism B, but the electric cylinder 640 and the like can also be used for purposes other than braking.

[0139] In addition, in this embodiment, an example has been shown in which the equalizer 652 is used to distribute the thrust of the electric cylinder 640, but the equalizer 652 can also be used for other purposes. For example, the equalizer 652 can be used for any purpose, such as distributing the power of an electric motor or the operating force of an operating tool by a passenger.

[0140] In addition, in this embodiment, the driving force is distributed from the equalizer 652 to the wires 653U and 653D, but the members to which the driving force is distributed from the equalizer 652 are not limited to the wires 653U and 653D. For example, the driving force may be distributed from the equalizer 652 to a rod or the like.

[0141] Although the equalizer 652 is disposed between the front wheels 6 and the rear wheels 7 in the longitudinal direction, the positional relationship between the equalizer 652 and the front wheels 6 and the rear wheels 7 in the longitudinal direction is not limited to this embodiment. Furthermore, although the equalizer 652 is disposed forward of the fuel tank 23, the positional relationship between the equalizer 652 and the fuel tank 23 in the longitudinal direction is not limited to this embodiment.

[0142] Although the high nut 661 protrudes forward from the main body 652a of the equalizer 652, the protruding direction relative to the main body 652a is not limited to the forward direction and the high nut 661 may protrude in other directions.

[0143] Furthermore, although the high nut 661 is connected to the first connecting shaft 652b and the second connecting shaft 652c, it may also be connected to a member other than the first connecting shaft 652b and the second connecting shaft 652c (such as the main body 652a).

[0144] Furthermore, although the cover member 670 covers the adjustment mechanism 660 and the like from above, below, front, rear, and left, it is sufficient that the cover member 670 covers the adjustment mechanism 660 and the like from at least one of the left and right sides. Furthermore, the cover member 670 may be omitted.

[0145] The present invention can be applied to a work vehicle.

[0146] REFERENCE SIGNS LIST 1 Tractor 22 Brake pedal 610 Brake lever 611a, 623b Elongated hole 620 First operating mechanism 623c, 653c Pin 640 Electric cylinder 650 Second operating mechanism B Brake mechanism

Claims

1. A work vehicle comprising: a brake lever capable of activating a brake mechanism when operated in a predetermined direction; a manual operation mechanism that connects a brake operating device that can be operated by a occupant to the brake lever, and capable of operating the brake lever in conjunction with the operation of the brake operating device; an electric operation mechanism that connects an electric actuator to the brake lever, and capable of operating the brake lever in conjunction with the operation of the electric actuator; and an independence mechanism that prevents either the manual operation mechanism or the electric operation mechanism from operating in conjunction with the operation of the other of the manual operation mechanism or the electric operation mechanism.

2. A work vehicle as claimed in claim 1, wherein the manual operation mechanism and the electric operation mechanism are each connected in parallel to the brake lever.

3. A work vehicle as described in claim 1, wherein the independent mechanism comprises: a manual side long hole formed in either one of the manual side first member that operates in conjunction with the brake operating device or the manual side second member that operates in conjunction with the brake lever; and a manual side connecting part provided on the other of the manual side first member or the manual side second member and inserted into the manual side long hole.

4. A work vehicle as described in claim 1, wherein the independent mechanism comprises: an electric side long hole formed in either one of the electric side first member that operates in conjunction with the electric actuator or the electric side second member that operates in conjunction with the brake lever; and an electric side connecting part provided on the other of the electric side first member or the electric side second member and inserted into the electric side long hole.

5. The work vehicle according to claim 1, wherein the independent mechanism comprises: a manual side long hole formed in either one of the manual side first member which operates in conjunction with the brake operating device, or the manual side second member which operates in conjunction with the brake lever; a manual side coupling part provided on the other of the manual side first member or the manual side second member and inserted into the manual side long hole; an electric side long hole formed in either one of the electric side first member which operates in conjunction with the electric actuator, or the electric side second member which operates in conjunction with the brake lever; and an electric side coupling part provided on the other of the electric side first member or the electric side second member and inserted into the electric side long hole.

6. A work vehicle as claimed in any one of claims 1 to 5, wherein the brake levers are provided in a pair on the left and right corresponding to a pair of left and right brake mechanisms for braking the left and right wheels, respectively, and the electric operation mechanism connects one of the electric actuators to the pair of left and right brake levers.

7. A work vehicle as described in claim 6, wherein the electric operation mechanism comprises: a rotating member that is rotatable about a rotation axis in response to the driving force of the electric actuator; and a distribution section that distributes and transmits the driving force of the electric actuator transmitted via the rotating member to a pair of left and right brake levers.

8. A work vehicle according to claim 7, wherein the electric actuator comprises an extendable rod, and the axial direction of the rotation shaft is oriented in a direction perpendicular to the extension direction of the rod.

9. A work vehicle as claimed in claim 1, wherein a pair of the brake levers are provided on the left and right so as to correspond to the brake mechanisms of the left and right wheels, respectively, and two of the electric operation mechanisms are provided so as to correspond to the pair of left and right brake levers.

Images