Work vehicles

Abstract

To provide a configuration excellent in operability in a work vehicle which has a cruise control function and is provided with a pair of brake pedals on the right and left.SOLUTION: A tractor includes rear wheels, a gear, brake pedals (a left brake pedal 14 and a right brake pedal 15), a brake device, a cruise control operation tool 16, and a cruise control device. The rear wheels are provided in a pair on the right and left. The gear changes transmission related to a vehicle speed. The brake pedals are provided in a pair on the right and left. The brake device activates brakes on the right and left rear wheels individually as a result of operation performed on the brake pedals. The cruise control device fixes the transmission of the gear when the cruise control operation tool 16 is operated, releases the fixation of the transmission of the gear when the left brake pedal 14 is operated, and releases the fixation of the transmission of the gear when the right brake pedal 15 is operated.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention mainly relates to a work vehicle having a cruise control function.

Background Art

[0002] The work vehicle of Patent Document 1 includes a cruise control operating tool. By rotating the cruise control operating tool by an operator, the shift of the transmission is fixed and the work vehicle can travel at a constant speed. Further, in the work vehicle of Patent Document 1, when the brake pedal is operated in a state where the cruise control is effective, the operating force is transmitted to the cruise control operating tool via a link mechanism. As a result, the cruise control operating tool rotates and the cruise control is released.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A single brake pedal is provided in the work vehicle of Patent Document 1. On the other hand, depending on the work vehicle, a pair of left and right brake pedals may be provided. Patent Document 1 only describes that the cruise control is released using a single brake pedal, and does not describe the operation in the case of having a pair of left and right brake pedals.

[0005] The present invention has been made in view of the above circumstances, and its main object is to provide a configuration with excellent operability in a work vehicle having a cruise control function and provided with a pair of left and right brake pedals. Means and Effects for Solving the Problems <00OO029>

[0006] The problems that this invention aims to solve are as described above, and next, the means for solving these problems and their effects will be explained.

[0007] In view of the present invention, a work vehicle having the following configuration is provided. That is, the work vehicle comprises a drive unit, a transmission, brake pedals, a braking device, a cruise control operating tool, and a cruise control device. The drive unit is provided in a pair, left and right. The transmission performs gear changes related to vehicle speed. The brake pedals are provided in a pair, left and right. The braking device applies brakes to the left and right drive units individually when the brake pedals are operated. The cruise control device fixes the gear changes of the transmission when the cruise control operating tool is operated. The first brake pedal is one of the left or right brake pedals. When the brake pedal is operated, the gear shift lock of the transmission is released. The second brake pedal is on the other side of the left and right sides. When the brake pedal is operated, the gear shift lock of the transmission is released. By operating the cruise control device, the transmission is switched between a fixed state in which the gear shifting is fixed and a released state in which the fixed state is released. The cruise control device includes a release mechanism for switching from the fixed state to the released state. The first brake pedal is connected to the release mechanism via a wire. The second brake pedal is connected to the release mechanism via a shaft. The release mechanism is activated even if only one of the first or second brake pedals is operated.

[0008] This allows the cruise control to be deactivated regardless of whether the left or right brake pedal is operated, resulting in a work vehicle with superior maneuverability. Furthermore, it can be implemented at a lower cost compared to a configuration that releases the fixed state using an electrical signal. In addition, while the first brake pedal and the release mechanism are connected using a wire, the remaining space can be used to connect the second brake pedal and the release mechanism using a shaft.

[0009] In the aforementioned work vehicle, the following configuration is preferable. That is, by operating the cruise control device, the gear shift of the transmission is switched between a fixed state and a released state in which the fixed state is released. The cruise control device is equipped with a release mechanism for switching from the fixed state to the released state. One of the left and right first brake pedals is connected to the release mechanism via a wire. The other of the left and right second brake pedals is connected to the release mechanism via a shaft.

[0010] This allows for a lower-cost implementation compared to configurations that release the fixed state using electrical signals. Furthermore, while the first brake pedal and the release mechanism are connected using a wire, the remaining space can be utilized to connect the second brake pedal and the release mechanism using a shaft.

[0011] In the aforementioned work vehicle, a gap is formed in at least one of the mechanism that transmits the operating force applied to the first brake pedal to the release mechanism, and the mechanism that transmits the operating force applied to the second brake pedal to the release mechanism, and it is preferable that the release mechanism is activated when the first brake pedal or the second brake pedal is operated beyond the gap.

[0012] This eliminates the need to adjust the release mechanism even when the brake pedal stroke is adjusted.

[0013] In the aforementioned work vehicle, the following configuration is preferable: The first brake pedal and the second brake pedal are connectable. The first brake pedal and the second brake pedal require different amounts of operation to activate the release mechanism. When the first brake pedal and the second brake pedal are operated while connected, the operating force is transmitted to the release mechanism via either the shaft or the wire.

[0014] This allows the release mechanism to be activated via a specific single mechanism, even when the left and right brake pedals are connected.

[0015] In the aforementioned work vehicle, the following configuration is preferable. That is, by operating the cruise control device, the gear shift of the transmission is switched between a fixed state and a released state in which the fixed state is released. When the brake pedal is operated, a restricting member is provided to restrict the operation of the cruise control device that switches from the released state to the fixed state.

[0016] This prevents the cruise control system from switching to a fixed state while the brakes are applied.

[0017] In the above work vehicle, it is preferable to adopt the following configuration. That is, the cruise control device includes a release mechanism for switching from the fixed state to the released state. The regulating member also serves as the release mechanism.

[0018] As a result, the number of components can be reduced.

Brief Description of the Drawings

[0019] [Figure 1] Side view of a tractor according to an embodiment of the present invention. [Figure 2] Plan view showing an operating tool arranged near the driver's seat. [Figure 3] Perspective view explaining a mechanism for transmitting an operating force applied to the brake pedal. [Figure 4] Side view explaining a mechanism for transmitting an operating force applied to the cruise control operating tool. <s [Figure 5] First perspective view for explaining that the cruise control is released by operating the brake pedal. [Figure 6] Second perspective view for explaining that the cruise control is released by operating the brake pedal. [Figure 7] Side view showing a state of pulling the first wire end using a wire operating member. [Figure 8] Side view showing that the cruise control cannot be started during the operation of the brake. [Figure 9] Side view showing the shape of an operating arm according to a modification. [Figure 10] Side view of a tractor equipped with a rollover protection frame. [Figure 11] Side view showing the structure of the rollover protection frame.

Embodiments for Carrying Out the Invention

[0020] Next, embodiments of the present invention will be described with reference to the drawings. Figure 1 is a side view of a tractor (work vehicle) 1 according to one embodiment of the present invention. Figure 2 is a top view of the tractor 1. In the following description, "left," "right," etc., refer to the left and right as seen from the perspective of the operator riding in the tractor 1.

[0021] The tractor 1 of this embodiment is a work vehicle used for agricultural or civil engineering work. The tractor 1 comprises a body 2 which includes a frame extending in the front-rear direction. The body 2 is supported by front wheels 3 and rear wheels 4 which serve as the running gear. The front wheels 3 and rear wheels 4 are each provided in pairs on the left and right sides. Crawlers may be provided instead of wheels.

[0022] A bonnet 5 is provided at the front of the tractor 1. Inside the bonnet 5 is an engine 6, which serves as the drive unit. The engine 6 generates power. The engine 6 is a diesel engine, but it may also be a gasoline engine. Alternatively, an electric motor may be provided instead of the engine 6.

[0023] A transmission 7 is provided at the rear of the vehicle body 2. The power output from the engine 6 is input to the transmission 7. Specifically, the transmission 7 is an HST (hydrostatic continuously variable transmission). The transmission 7 is equipped with a hydraulic pump, a hydraulic motor, and various drive transmission shafts. The hydraulic pump is driven by the engine's power, thereby discharging oil. The hydraulic motor is operated by the oil discharged by the hydraulic pump, rotating the drive transmission shaft. The drive transmission shaft is connected to the rear wheels 4. This allows the tractor 1 to be driven using the power output from the engine 6. The hydraulic pump is also equipped with a movable swashplate that changes the amount of oil discharged according to the inclination angle, and the rotational speed of the drive transmission shaft can be changed according to the inclination angle of the movable swashplate, thereby changing the rotational speed (i.e., speed) of the rear wheels 4. Note that an HMT or a mechanical transmission may be provided instead of the HST. A PTO shaft (not shown) is also connected to the transmission 7. An implement can be attached to the PTO shaft. The power from engine 6 is output from the PTO shaft via the transmission 7.

[0024] Behind the hood 5 is a driver's seat 8 for the operator to sit in. Various controls for the operator to perform various operations are provided around the driver's seat 8. Specifically, as shown in Figure 2, a steering wheel 11, forward pedals 12, reverse pedals 13, left brake pedal 14, right brake pedal 15, cruise control controls 16, and parking brake controls 17 are provided around the driver's seat 8.

[0025] When the operator operates the forward pedal 12, the drive shaft of the transmission 7 rotates in the direction that moves the tractor 1 forward. This allows the tractor 1 to move forward. When the operator operates the reverse pedal 13, the drive shaft of the transmission 7 rotates in the direction that moves the tractor 1 backward. This allows the tractor 1 to move backward. In addition, the tilt angle of the movable swashplate changes depending on the amount the forward pedal 12 or reverse pedal 13 is pressed, so a gear change can be performed.

[0026] Each of the left and right rear wheels 4 is equipped with a brake device 9. The brake device 9 is a disc brake and has a rotating plate that rotates integrally with the rear wheel 4, and an operating member that contacts the rotating plate to decelerate or stop its rotation. When the operator operates the left brake pedal 14, the operating member of the left brake device 9 is activated, and the left rear wheel 4 is braked. On the other hand, when the operator operates the right brake pedal 15, the operating member of the right brake device 9 is activated, and the right rear wheel 4 is braked. The mechanism for transmitting power from the left brake pedal 14 or the right brake pedal 15 to the brake device 9 will be described later.

[0027] The cruise control device 16 is a device for implementing the cruise control function. The cruise control function is a function that allows the tractor 1 to travel at a constant speed without operator intervention by fixing the gear shift of the transmission 7. The operator can switch between a fixed state, where the gear shift is fixed, and a released state, where the fixed state is released, by operating the cruise control device 16. The mechanism for implementing the cruise control will be described later.

[0028] The parking brake operator 17 is an operator for activating the parking brake. The parking brake is used when parking the tractor 1 and maintains braking force even when the operator leaves the driver's seat 8. By operating the parking brake operator 17, the operator can switch between a brake-activated state where the parking brake is active and a brake-released state where the parking brake is released. The mechanism for implementing the parking brake will be described later.

[0029] Next, referring to Figure 3, the mechanism for transmitting the operating force applied to the left brake pedal 14 and the right brake pedal 15 to the brake device 9 will be described.

[0030] Figure 3 shows a mechanism for transmitting the operating force applied to the left brake pedal 14 to the brake device 9, which includes a left brake arm 21, a left brake shaft 22, a left brake transmission link 23, and a left brake operating member 24. One end of the left brake arm 21 is connected to the left brake pedal 14, and the other end of the left brake arm 21 is connected to the left brake shaft 22.

[0031] The left brake shaft 22 is provided so as to be rotatable relative to the base shaft 30. Therefore, by pressing the left brake pedal 14, the left brake shaft 22 can be rotated relative to the base shaft 30.

[0032] A left brake transmission link 23 is connected to the left brake shaft 22. The left brake transmission link 23 includes a rod that moves up and down in conjunction with the rotation of the left brake shaft 22, and a shaft that rotates in accordance with the rotation of the rod. A left brake operating member 24 is connected to the left brake transmission link 23. When the operating force applied to the left brake pedal 14 is transmitted, the left brake operating member 24 slides in the front-rear direction. A brake device 9 is connected to the other end of the left brake operating member 24, and the brake is activated using the transmitted operating force.

[0033] Figure 3 shows a mechanism for transmitting the operating force applied to the right brake pedal 15 to the brake device 9, which includes a right brake arm 31, a right brake shaft 32, a base shaft 30, a right brake transmission link 33, and a right brake operating member 34. One end of the right brake arm 31 is connected to the right brake pedal 15, and the other end of the right brake arm 31 is connected to the right brake shaft 32.

[0034] The right brake shaft 32 is fixed to the base shaft 30, and the right brake shaft 32 and the base shaft 30 rotate together. The right brake transmission link 33 and the right brake operating member 34 are connected to the base shaft 30. These have substantially the same or symmetrical configuration as the left brake transmission link 23 and the left brake operating member 24, so their description is omitted.

[0035] As described above, in this embodiment, the left brake pedal 14 and the right brake pedal 15 are provided independently, allowing the left and right brake devices 9 to be operated independently. Alternatively, the left brake pedal 14 and the right brake pedal 15 can be connected using a brake connecting member 20. In this case, operating just one of the brake pedals will rotate the other brake pedal simultaneously, thus allowing both the left and right brake devices 9 to be operated.

[0036] Next, the cruise control device 40 will be described with reference to Figure 4.

[0037] The cruise control device 40 operates based on the operating force applied to the cruise control operating tool 16, switching between the fixed state and the released state described above. As shown in Figure 4, the cruise control device 40 comprises an operating arm 41, a transmission shaft 42, a link 43, a rod 44, and a movable engagement part 45.

[0038] One end of the operating arm 41 is connected to the cruise control device 16. The other end of the operating arm 41 is connected to the transmission shaft 42. A link 43 is further fixed to the transmission shaft 42. A rod 44 is connected to the link 43. By rotating the link 43 up and down, the rod 44 can be slid up and down. A movable engagement part 45 is connected to the rod 44 via a link. The movable engagement part 45 moves toward and away from the fixed engagement part 12b by rotating the cruise control device 16 up and down.

[0039] A pedal arm 12a is connected to the forward pedal 12. A fixed engagement part 12b is connected to the pedal arm 12a. The forward pedal 12, pedal arm 12a, and fixed engagement part 12b are rotatable as a single unit.

[0040] Here, the fixed engagement portion 12b is comb-shaped. The movable engagement portion 45 has a tapered projection. The projection of the movable engagement portion 45 can engage with the comb-shaped recess of the fixed engagement portion 12b. This allows the tilt angle of the forward pedal 12 to be kept constant. As a result, the gear shift of the transmission 7 is fixed, and the travel speed of the tractor 1 can be kept constant. From this state, by rotating the cruise control operating tool 16 downward, the movable engagement portion 45 separates from the fixed engagement portion 12b, and the fixed state can be released.

[0041] In this embodiment, the tractor 1 releases the fixed state of the cruise control device 40 not only when the cruise control control device 16 is operated, but also when the left brake pedal 14 or the right brake pedal 15 is operated. The structure for this purpose will be described in detail below.

[0042] First, referring to Figures 5 to 7, the structure for releasing the fixed state of the cruise control device 40 using the operating force applied to the left brake pedal 14 will be described. As described above, applying operating force to the left brake pedal 14 causes the left brake shaft 22 to rotate. Also, as shown in Figures 5 and 6, a wire operating member 25 is fixed to the outer surface of the left brake shaft 22.

[0043] The wire operating member 25 rotates integrally with the left brake shaft 22. The wire is operated by the rotation of the wire operating member 25. The wire is inserted into the wire tube 26 shown in Figures 5 and 6. One end of the wire, the first wire end 27, is attached to the wire operating member 25. As shown in Figure 7, when the left brake pedal 14 is operated, the left brake arm 21 and the left brake shaft 22 rotate, causing the wire operating member 25 to rotate upward. This causes the wire operating member 25 to contact the first wire end 27 and pull the wire.

[0044] Furthermore, as shown in Figure 7, when the cruise control device 40 is in a fixed state and no operating force is applied to the left brake pedal 14, a gap L1 is formed between the wire operating member 25 and the first wire end 27. As a result, immediately after pressing the left brake pedal 14, the wire operating member 25 does not pull the wire, and the wire operating member 25 pulls the wire only when the left brake pedal 14 is operated by an amount corresponding to the gap L1.

[0045] If the gap L1 were zero, the following problem would arise. Specifically, if the stroke of the left brake pedal 14 is adjusted due to wear or looseness of the brake device 9, the wire may be pulled even when the left brake pedal 14 is not being operated. In that case, the wire would need to be adjusted. In this respect, by forming a gap L1, even if the stroke of the left brake pedal 14 is adjusted, wire adjustment is basically unnecessary.

[0046] The other end of the wire, the second wire end 28, is connected to the operating arm 41. More specifically, the cruise control device 40 includes a release mechanism 60 that releases the fixed state in response to brake operation. The release mechanism 60 includes a wire connecting portion 61 attached to the operating arm 41. The wire connecting portion 61 connects the second wire end 28 to the operating arm 41. The wire connecting portion 61 is installed in a position where the fixed state of the cruise control device 40 is released when the wire is pulled. That is, in this embodiment, the fixed state is released by rotating the cruise control operating tool 16 downward. Therefore, the wire connecting portion 61 is provided in a position where the cruise control operating tool 16 rotates downward when the wire is pulled.

[0047] Thus, the left brake pedal 14, which serves as the first brake pedal, is connected to the release mechanism 60 via a mechanism including a wire.

[0048] Next, referring mainly to Figure 5, a structure for releasing the fixed state of the cruise control device 40 using the operating force applied to the right brake pedal 15 will be described. As described above, applying operating force to the right brake pedal 15 causes the base shaft 30 to rotate. The operating force applied to the right brake pedal 15 and transmitted to the base shaft 30 is transmitted to the release link 62 of the release mechanism 60 via the second brake shaft 51 and the second brake arm 52 shown in Figure 5.

[0049] The second brake shaft 51 is fixed to the base shaft 30 and rotates integrally with the base shaft 30. One end of the second brake arm 52 is fixed to the second brake shaft 51 and rotates integrally with the second brake shaft 51. A release link 62 is connected to the middle section of the second brake arm 52. The release link 62 connects the middle section of the second brake arm 52 to a member that supports the transmission shaft 42. A release pin 63 is also attached to the release link 62. With this configuration, the release pin 63 can be moved by operating the right brake pedal 15.

[0050] Here, the release pin 63 is positioned near the operating arm 41. When an operating force is applied to the right brake pedal 15, the release pin 63 presses against the operating arm 41, causing it to rotate. The direction in which the release pin 63 rotates the operating arm 41 is the direction in which the fixed state of the cruise control device 40 is released. Thus, the fixed state of the cruise control device 40 can be released by the operating force applied to the right brake pedal 15.

[0051] Furthermore, when the cruise control device 40 is in a fixed state and no operating force is applied to the right brake pedal 15, a gap L2 is formed between the release pin 63 and the operating arm 41, as shown in Figure 5. As a result, immediately after the right brake pedal 15 is pressed, the release pin 63 does not press against the operating arm 41, and the release pin 63 presses against the operating arm 41 only when the right brake pedal 15 is operated by an amount corresponding to the gap L2.

[0052] Furthermore, in this embodiment, the amount of movement of the left brake pedal 14, which corresponds to the gap L1 between the wire operating member 25 and the first wire end 27, is greater than the amount of movement of the right brake pedal 15, which corresponds to the gap L2 between the release pin 63 and the operating arm 41. Therefore, when the left brake pedal 14 and the right brake pedal 15 are connected and operated, the release pin 63 and the operating arm 41 come into contact before the wire operating member 25 and the first wire end 27. As a result, the release pin 63 presses against the operating arm 41, releasing the fixed state of the cruise control device 40. Note that the amount of movement of the left brake pedal 14, which corresponds to the gap L1 between the wire operating member 25 and the first wire end 27, may be less than the amount of movement of the right brake pedal 15, which corresponds to the gap L2 between the release pin 63 and the operating arm 41.

[0053] Thus, the right brake pedal 15, which acts as a second brake pedal, is connected to the release mechanism 60 via a mechanism that includes a shaft (base shaft 30).

[0054] Here, the second brake arm 52 is used not only to release the fixed state of the cruise control device 40, but also to activate the parking brake. As shown in Figure 5, the parking brake operating tool 17 is connected to a lever arm 17a and a lever-side engaging part 17b. The parking brake operating tool 17, lever arm 17a, and lever-side engaging part 17b rotate as a single unit.

[0055] The lever-side engaging portion 17b is comb-shaped. On the other hand, the other end of the second brake arm 52 is connected to an arm-side engaging portion 53 that fits into the comb-shaped recess of the lever-side engaging portion 17b. That is, by operating the parking brake operating tool 17 to engage the lever-side engaging portion 17b and the arm-side engaging portion 53, the rotation of the base shaft 30 can be maintained. As a result, the brake device 9 can be activated without operating the right brake pedal 15. Also, since the left brake pedal 14 and the right brake pedal 15 are connected when parked, the left brake device 9 can also be activated.

[0056] Furthermore, the tractor 1 has a mechanism to prevent the cruise control device 40 from switching from the disengaged state to the fixed state while the brakes are applied. This prevents the cruise control from being activated at a time when the operator intends to decelerate.

[0057] Figure 8 illustrates the positions of the second brake arm 52, release link 62, and release pin 63 when the brake is applied. Furthermore, the position of the cruise control operating device 16 in the released state is shown by a solid line. Here, if the operator rotates the cruise control operating device 16 upward (i.e., when an operation is performed to switch from the released state to the fixed state), the operating arm 41 interferes with the release pin 63, as shown by the dashed line in Figure 8. In other words, the movement trajectory of the operating arm 41 when the cruise control operating device 16 is operated from the released state to the fixed state interferes with the position of the release pin 63 when the brake is applied. Therefore, when the brake is applied, switching the cruise control device 40 from the released state to the fixed state is restricted. In addition, in this embodiment, since the release pin 63, which is part of the release mechanism 60, functions as a restricting member, the number of parts can be reduced compared to a configuration in which a dedicated restricting member is provided. However, a dedicated restricting member may be provided.

[0058] Note that the shape of the operating arm 41 shown in Figure 8 is just one example, and the operating arm 41 may have the shape shown in Figure 9. In the operating arm 41 shown in Figure 9, a contact surface 41a is formed at the end opposite the cruise control operating tool 16. The contact surface 41a is the part of the lever's contour that has been made straight. When the cruise control operating tool 16 is operated from the released state to the fixed state, the movement trajectory of the contact surface 41a interferes with the position of the release pin 63 when the brake is engaged. By making the contact surface 41a straight rather than curved, the operating arm 41 can be reliably stopped when the contact surface 41a contacts the release pin 63.

[0059] Next, with reference to Figures 10 and 11, a tractor 1a different from the embodiment described above will be described. The tractor 1a is equipped with a rollover protection frame 70. The rollover protection frame 70 is a component that protects the operator in the driver's seat 8 when the tractor 1a rolls over. The rollover protection frame 70 is provided in front of the driver's seat 8 and at least to the side. Also, as shown by the thick arrows in Figure 10, the rollover protection frame 70 can switch between an upright position (solid line) and a tilted position (dashed line).

[0060] As shown in Figure 11, the tip-over protection frame 70 comprises a lower frame 71 and an upper frame 72. By rotating the upper frame 72 relative to the lower frame 71 using a rotation axis 73, the tip-over protection frame 70 can be switched between an upright position and a tilted position.

[0061] The lower frame 71 and the upper frame 72 have a U-shaped cross-section and an opening. A rubber plate 74 is placed in the opening of the upper frame 72. The rubber plate 74 is located at a position that includes the end of the upper frame 72 on the lower frame 71 side (in other words, a position that includes the rotation axis 73). Therefore, the rubber plate 74 is bent in the tilted position and straight in the upright position. As a result, the elastic force of the rubber plate 74 can reduce the operating load when switching the tipping protection frame 70 from the tilted position to the upright position.

[0062] In this embodiment, a rubber plate 74 is placed on the lower frame 71, but a block-shaped rubber body capable of closing the opening in the upper frame 72 may be placed on the upper frame 72. Furthermore, the rubber plate 74 or rubber body may be provided across both the upper frame 72 and the lower frame 71.

[0063] The tractor 1 of this embodiment has the following feature 1. Specifically, the tractor 1 comprises rear wheels 4, a transmission 7, brake pedals (left brake pedal 14 and right brake pedal 15), a brake device 9, a cruise control operating device 16, and a cruise control device 40. The rear wheels 4 are provided in pairs, left and right. The transmission 7 performs gear changes related to vehicle speed. The brake pedals are provided in pairs, left and right. The brake device 9 applies brakes to the left and right rear wheels 4 individually when the brake pedals are operated. The cruise control device 40 locks the gear change of the transmission 7 when the cruise control operating device 16 is operated, releases the gear change lock of the transmission 7 when the left brake pedal 14 is operated, and releases the gear change lock of the transmission 7 when the right brake pedal 15 is operated.

[0064] This allows the cruise control to be deactivated by operating either the left or right brake pedal, resulting in a tractor with excellent maneuverability.

[0065] The tractor 1 of this embodiment has the following feature 2. Specifically, in the tractor 1, by operating the cruise control operating tool 16, the gear shift of the transmission 7 is switched between a fixed state and a released state in which the fixed state is released. The cruise control device 40 is equipped with a release mechanism 60 for switching from the fixed state to the released state. The left brake pedal 14 is connected to the release mechanism 60 via a wire. The right brake pedal 15 is connected to the release mechanism 60 via a shaft.

[0066] This allows for a lower-cost implementation compared to configurations that release the fixed state using electrical signals. Furthermore, while the left brake pedal 14 and the release mechanism 60 are connected using a wire, the remaining space can be utilized to connect the right brake pedal 15 and the release mechanism 60 using a shaft.

[0067] The tractor 1 of this embodiment has the following feature 3. Specifically, in the tractor 1, a gap is formed in at least one of the mechanisms that transmit the operating force applied to the left brake pedal 14 to the release mechanism 60, and the mechanism that transmits the operating force applied to the right brake pedal 15 to the release mechanism 60. When the left brake pedal 14 or the right brake pedal 15 is operated beyond this gap, the release mechanism 60 is activated.

[0068] This eliminates the need to adjust the release mechanism 60 even when the brake pedal stroke is adjusted.

[0069] The tractor 1 of this embodiment has the following feature 4. Specifically, in the tractor 1, the left brake pedal 14 and the right brake pedal 15 are connectable. The left brake pedal 14 and the right brake pedal 15 require different amounts of operation to activate the release mechanism 60. When the left brake pedal 14 and the right brake pedal 15 are operated while connected, the operating force is transmitted to the release mechanism 60 via either the shaft or the wire.

[0070] This allows the release mechanism to be activated via a specific single mechanism, even when the left and right brake pedals are connected.

[0071] The tractor 1 of this embodiment has the following feature 5. Specifically, in the tractor 1, by operating the cruise control device 16, the gear shift of the transmission 7 is switched between a fixed state in which the gear shift is fixed and a released state in which the fixed state is released. A release pin 63 is provided that restricts the operation of the cruise control device 16 to switch from the released state to the fixed state when the brake pedal is operated.

[0072] This prevents the cruise control device 40 from switching to a fixed state when the brakes are applied.

[0073] The tractor 1 of this embodiment has the following feature 6. Specifically, in the tractor 1, the cruise control device 40 is equipped with a release mechanism 60 for switching from a fixed state to a released state. The release pin 63, which acts as a regulating member, also serves as the release mechanism 60.

[0074] This reduces the number of parts.

[0075] Features 1 through 6 described above can be combined as appropriate, as long as no contradictions arise. For example, feature 3 can be combined with at least one of features 1 or 2. Feature 4 can be combined with at least one of features 1 through 3. Feature 5 can be combined with at least one of features 1 through 4. Feature 6 can be combined with at least one of features 1 through 5.

[0076] Although preferred embodiments of the present invention have been described above, the above configuration can be modified as follows, for example.

[0077] In the above embodiment, the left brake pedal 14 is connected to the release mechanism 60 via a wire, and the right brake pedal 15 is connected to the release mechanism 60 via a shaft. Alternatively, the left brake pedal 14 may be connected to the release mechanism 60 via a shaft, and the right brake pedal 15 may be connected to the release mechanism 60 via a wire. Or, both the left and right brake pedals may be connected to the release mechanism 60 via wires, or both the left and right brake pedals may be connected to the release mechanism 60 via shafts.

[0078] In the above embodiment, gaps L1 and L2 are formed, but at least one of the gaps may be eliminated.

[0079] Although the cruise control device 40 in the above embodiment is mechanical, it may also be electric. That is, it may be configured to accelerate and decelerate so that the detected value of the vehicle speed sensor remains constant. In this case, the release mechanism can also be electric. That is, a sensor may be provided to detect when the left brake pedal 14 or the right brake pedal 15 is operated, and control may be performed to stop the cruise control in response to the detection by the sensor.

[0080] The cruise control device 16 and the parking brake device 17 are lever-type, but they may also be push-type or pedal-type.

[0081] Although the above embodiments describe an example of applying the present invention to a tractor, the present invention can also be applied to other work vehicles, such as agricultural work vehicles like rice transplanters, or construction or civil engineering work vehicles like hydraulic excavators. [Explanation of Symbols]

[0082] 1. Tractor (work vehicle) 3. Front wheels (running section) 4. Rear wheels (running section) 7. Transmission 9. Brake system 14. Left brake pedal (brake pedal) 15 Right brake pedal (brake pedal) 16. Cruise control controls 26 Wire Tube (Wire) 27 First wire end (wire) 28 Second wire end (wire) 30 Base Shaft (Shaft) 32 Right brake shaft (shaft) 40. Cruise control system 51. Second brake shaft (shaft) 60 Release mechanism 63 Release pin (regulating member) L1 Gap L2 Gap

Claims

1. A pair of running sections are provided on the left and right sides, A transmission that changes the vehicle speed, A pair of brake pedals are provided on the left and right sides, A braking device that, when the aforementioned brake pedal is operated, applies the brakes to the left and right sections of the travel unit individually, Cruise control controls, A cruise control device that locks the gear shift of the transmission when the cruise control device is operated, releases the gear shift lock of the transmission when the first brake pedal, which is one of the left or right brake pedals, is operated, and releases the gear shift lock of the transmission when the second brake pedal, which is the other of the left or right brake pedals, is operated. Equipped with, By operating the cruise control device, the gear shift of the transmission is switched between a fixed state in which the gear shift is fixed and a released state in which the fixed state is released. The cruise control device includes a release mechanism for switching from the fixed state to the released state, The first brake pedal is connected to the release mechanism via a wire, The second brake pedal is connected to the release mechanism via a shaft, A work vehicle characterized in that the release mechanism is activated even if only one of the first brake pedal and the second brake pedal is operated.

2. A work vehicle according to claim 1, A work vehicle characterized in that a gap is formed in at least one of the mechanisms for transmitting the operating force applied to the first brake pedal to the release mechanism, and the mechanism for transmitting the operating force applied to the second brake pedal to the release mechanism, and the release mechanism is activated when the first brake pedal or the second brake pedal is operated beyond the gap.

3. A work vehicle according to claim 2, The first brake pedal and the second brake pedal are connectable. The first brake pedal and the second brake pedal require different amounts of operation to activate the release mechanism. A work vehicle characterized in that when the first brake pedal and the second brake pedal are operated while connected, the operating force is transmitted to the release mechanism via only one of the shaft or the wire.

4. A work vehicle according to claim 1, By operating the cruise control device, the gear shift of the transmission is switched between a fixed state in which the gear shift is fixed and a released state in which the fixed state is released. A work vehicle characterized by being provided with a restricting member that restricts the operation of the cruise control device that switches from the released state to the fixed state when the brake pedal is operated.

5. A work vehicle according to claim 4, The cruise control device includes a release mechanism for switching from the fixed state to the released state, A work vehicle characterized in that the restricting member also serves as the release mechanism.

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