Work vehicle

Abstract

To provide a work vehicle which is simply configured to enable one brake sensor to determine states of operation of stepping-on right and left brake pedals.SOLUTION: A work vehicle is provided with contact parts 38 that can move along a moving direction of parts to be contacted 25e and 26e by operation of stepping-on and operation of returning brake pedals 25 and 26, and can contact both parts to be contacted 25e and 26e, and a brake sensor 37 that can sense movement of the contact parts 38. The contact parts 38 are provided on positions where the parts to be contacted 25e and 26e are moved in a direction which the parts get away from the contact parts 38 by operation of stepping-on the brake pedals 25 and 26, and are energized toward the moving direction of the parts to be contacted 25e and 26e by operation of stepping-on the brake pedals 25 and 26.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a work vehicle equipped with right and left brakes and right and left brake pedals.

Background Art

[0002] In a tractor which is an example of a work vehicle, for example, when an operator steps on the right brake pedal while operating the steering wheel to the right, in addition to the front wheels being steered to the right, the right rear wheel (corresponding to the traveling device) is braked, and there is a configuration that enables a small turn to the right. When stopping the vehicle body in this tractor, the operator steps on both the right and left brake pedals.

[0003] In the work vehicle as described above, as disclosed in Patent Document 1, there is a configuration in which various operations are performed based on both the right and left brake pedals being stepped on. An example of this various operation is shown below.

[0004] When the transmission for traveling is held at a desired shift position and the work vehicle is traveling at a constant speed, if both the right and left brake pedals are stepped on, the holding of the transmission for traveling is released, and the transmission for traveling is automatically operated to the low-speed side, and there is a configuration in which the load applied to the right and left brakes is reduced. When both the right and left brake pedals are stepped on, since there is a little time until the right and left brakes are actually braked (play of the right and left brake pedals), there is a configuration in which the transmission for traveling is automatically operated to the low-speed side during this time.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When performing various operations as described above, it is necessary to determine and detect whether one of the right and left brake pedals has been depressed or both the right and left brake pedals have been depressed.

[0007] In Patent Document 1, a right brake sensor for detecting the operation position of the right brake pedal and a left brake sensor for detecting the operation position of the left brake pedal are provided, and based on the detection values of the right and left brake sensors, the state of the depression operation of the right and left brake pedals is determined.

[0008] In this case, it has been considered possible to determine the state of the depression operation of the right and left brake pedals with a single brake sensor, and there is a demand to simplify the configuration for determining the state of the depression operation of the right and left brake pedals with a single brake sensor.

[0009] An object of the present invention is to simplify the configuration for determining the state of the depression operation of the right and left brake pedals with a single brake sensor in a work vehicle equipped with right and left brakes and right and left brake pedals.

Means for Solving the Problem

[0010] The work vehicle of the present invention includes right and left traveling devices, right and left brakes capable of braking the right and left traveling devices, an arm portion swingably provided around a pedal axis along the left - right direction and extending to a position higher than the pedal axis, a stepping portion attached to the upper portion of the arm portion, and a contact portion. It has right and left brake pedals capable of braking - operating the right and left brakes by being stepped on, a contact portion movably provided along the moving direction of the contact portion by stepping on and returning the brake pedals, and capable of contacting both of the contact portions of the right and left brake pedals, and a brake sensor capable of detecting the movement of the contact portion. The contact portion is provided at a position where the contact portion moves away from the contact portion by stepping on the brake pedal, and is biased in the moving direction of the contact portion by stepping on the brake pedal. When one of the right and left brake pedals is stepped on, the contact portion contacts and stops the contact portion of the other of the right and left brake pedals, so that the contact portion does not follow the movement of the contact portion of one of the right and left brake pedals. When both of the right and left brake pedals are stepped on, the contact portion moves following the movement of the contact portions of both of the right and left brake pedals, and the fact that both of the right and left brake pedals are stepped on is detected by the brake sensor.

[0011] According to the present invention, when the right and left brake pedals are not stepped on, the contact portion is biased toward the contact portions of the right and left brake pedals and contacts and stops at the contact portions of the right and left brake pedals.

[0012] According to the present invention, in the above - mentioned state, when the right brake pedal is stepped on, the contact portion of the right brake pedal moves in a direction away from the contact portion. In this case, since the left brake pedal is not stepped on, the contact portion contacts and stops at the contact portion of the left brake pedal. When the left brake pedal is depressed, the contacted portion of the left brake pedal moves in a direction away from the contact portion. In this case, since the right brake pedal is not being depressed, the contact portion is in contact with and stopped by the contacted portion of the right brake pedal.

[0013] As a result, the contact portion is stopped by the contacted portion of the other one of the right and left brake pedals even when one of the right and left brake pedals is depressed. Since the contact portion is stopped, the brake sensor does not detect a state where both the right and left brake pedals are depressed.

[0014] According to the present invention, when both the right and left brake pedals are depressed, the contacted portions of both the right and left brake pedals move in a direction away from the contact portion, and there is no longer anything to stop the contact portion. As a result, the contact portion moves in the moving direction of the contacted portions of both the right and left brake pedals so as to follow the contacted portions of both the right and left brake pedals. Since the contact portion moves, the brake sensor detects a state where both the right and left brake pedals are depressed.

[0015] As described above, according to the present invention, a configuration for discriminating the depressed states of the right and left brake pedals by a single brake sensor can be simply configured by simple members such as the contact portion and the contacted portions of the brake pedals.

[0016] In the present invention, it is preferable that the arm portion has a first portion that is swingable around the pedal axis and extends forward from the pedal axis, and a second portion that extends upward from the front portion of the first portion, the stepped portion is attached to the upper portion of the second portion, and the contacted portion extends forward from the second portion.

[0017] According to the present invention, the contacted portion extends forward from the second portion of the arm portion of the brake pedal, and the brake sensor and the contact portion are provided at positions away from the brake pedal forward. As a result, since the brake sensor and the contact portion are provided away from the arm portion and the stepping portion of the brake pedal, the brake sensor and the contact portion can be provided without difficulty while avoiding interference with the arm portion and the stepping portion of the brake pedal.

[0018] In the present invention, it is preferable that the contact portion has a contact arm swingable around a detection axis along the left - right direction, and a contact pin provided at a swing end portion of the contact arm and capable of contacting the contacted portions of both the right and left brake pedals.

[0019] According to the present invention, since the contact portion has a contact arm swingable around a detection axis along the left - right direction and a contact pin, the pedal axis of the brake pedal and the detection axis of the contact portion are aligned with each other, and the moving direction of the contacted portion of the brake pedal and the moving direction of the contact portion are aligned with each other. As a result, when both the right and left brake pedals are stepped on, the contact portion can follow the contacted portions of both the right and left brake pedals without difficulty, so that the determination of the stepping operation state of the right and left brake pedals by one brake sensor can be stably performed.

[0020] In the present invention, it is preferable that the brake sensor has a detection axis rotatable around the detection axis, and the contact arm is attached to the detection axis.

[0021] According to the present invention, when the brake sensor has a detection axis rotatable around the detection axis, by attaching the contact arm of the contact portion to the detection axis of the brake sensor, it is advantageous in terms of simplifying the configuration for determining the stepping operation state of the right and left brake pedals by one brake sensor.

[0022] In the present invention, at least one of the contact portions of the right and left brake pedals is formed toward the other contact portion, the contact portions of both the right and left brake pedals are provided close to each other, the contact arm is provided on the right or left lateral side with respect to the contact portions of the right and left brake pedals, and the contact pin extends from the swing end portion of the contact arm toward the contact portions of the right and left brake pedals and can contact the contact portions of both the right and left brake pedals, which is preferable.

[0023] According to the present invention, since the contact portions of the right and left brake pedals are provided close to each other, the contact portions of the right and left brake pedals are provided in a compact manner. The contact portion is provided on the right or left lateral side with respect to the contact portions of the right and left brake pedals, and the contact portions of the right and left brake pedals and the contact portion are provided in a small space. Thereby, it is possible to make the arrangement of the contact portions of the right and left brake pedals and the contact portion compact.

[0024] In the present invention, the contact portion of the right brake pedal is formed toward the contact portion of the left brake pedal, the contact portion of the left brake pedal is formed toward the contact portion of the right brake pedal, and it is preferable that the contact portions of the right and left brake pedals are provided between the right and left brake pedals in a front view.

[0025] According to the present invention, when the contact portions of the right and left brake pedals are provided close to each other, the contact portions of both the right and left brake pedals are formed so as to be close to each other and are provided between the right and left brake pedals in a front view. Thereby, it is possible to make the arrangement of the contact portions of the right and left brake pedals compact.

[0026] In the present invention, it is preferable that the contact portion has a contact arm that is swingable around a detection axis along the left - right direction and is provided between the contacted portions of the right and left brake pedals in a plan view, and a contact pin that is provided at a swing end portion of the contact arm, extends rightward and leftward from the contact arm, and can contact the contacted portions of both the right and left brake pedals.

[0027] According to the present invention, in a state where the contact pins of the contact portion are in contact with the contacted portions of the right and left brake pedals, since the contact arm of the contact portion is provided between the contacted portions of the right and left brake pedals in a plan view, it is possible to make the arrangement of the contacted portions of the right and left brake pedals and the contact portion more compact.

[0028] According to the present invention, in a state where the contact pins of the contact portion are in contact with the contacted portions of the right and left brake pedals, the contact portion (contact arm and contact pin) and the contacted portions of the right and left brake pedals are in a state that is nearly left - right symmetric in a plan view. Thereby, when the right brake pedal is depressed and when the left brake pedal is depressed, the determination of the depressed states of the right and left brake pedals by one brake sensor is stabilized.

[0029] In the present invention, it is preferable that a stopper portion is provided to stop the follow - up of the contact portion to the contacted portion at a predetermined position set in advance.

[0030] According to the present invention, when both the right and left brake pedals are depressed and the contact arm of the contact portion follows the contacted portions of the right and left brake pedals, when the contact portion has moved by a required length, it is stopped by the stopper portion, and the position of the stopper portion may be set so that the contacted portions of the right and left brake pedals are separated from the contact portion. Thereby, it is possible to prevent the contact portion from following the contacted portions of the right and left brake pedals more than necessary, which is advantageous in terms of preventing damage to the contact portion.

Brief Description of the Drawings

[0031]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0032] Figures 1 to 9 show a tractor which is an example of a work vehicle. In Figures 1 to 9, F indicates the forward direction, B indicates the rearward direction, U indicates the upward direction, D indicates the downward direction, R indicates the right direction, and L indicates the left direction.

[0033] (Overall Configuration of the Tractor) As shown in Figure 1, the right and left front wheels 1 are provided at the front part of the machine body 3, and the right and left rear wheels 2 (corresponding to the traveling device) are provided at the rear part of the machine body 3. The machine body 3 is supported by the front wheels 1 and the rear wheels 2.

[0034] The operation unit 11 is provided on the airframe 3, and the driver's seat 12, the steering wheel 13 for steering the front wheels 1, the floor 10, etc. are provided on the operation unit 11. The ROPS frame 40 is provided at the rear part of the operation unit 11, and a roof 41 covering the upper part of the operation unit 11 is attached to the upper part of the ROPS frame 40.

[0035] The airframe 3 is configured by connecting the engine 4, the clutch housing 5, the continuously variable transmission 6, and the transmission case 7. The front frame 8 is connected to the engine 4 and the clutch housing 5, the front axle case 9 is attached to the front frame 8, and the front wheels 1 are provided on the right and left parts of the front axle case 9. The rear wheels 2 are provided on the right and left parts at the rear of the transmission case 7.

[0036] An arch-shaped pillar frame 42 (see FIG. 3) is attached across the right and left parts of the clutch housing 5, and a bonnet 43 covering the engine 4 is attached to the upper part of the pillar frame 42 so as to be openable and closable. The state shown in FIG. 1 is a state where the bonnet 43 is operated to the closed position, and the bonnet 43 is opened upward with the rear part of the bonnet 43 as a fulcrum.

[0037] (Transmission configuration of the running system) As shown in FIG. 2, the sub-transmission 14, the rear-wheel differential device 15, and the front-wheel transmission 16 are provided inside the transmission case 7. The power of the engine 4 is transmitted to the continuously variable transmission 6 and shifted, and is transmitted from the sub-transmission 14 through the rear-wheel differential device 15 to the right and left rear wheels 2.

[0038] The power branched between the sub-transmission 14 and the rear-wheel differential device 15 is transmitted to the front-wheel transmission 16, and is transmitted from the transmission shaft 17 through the front-wheel differential device 18 provided inside the front axle case 9 to the right and left front wheels 1.

[0039] The continuously variable transmission 6 is configured as a hydrostatic type and can continuously shift the power of the engine 4 in the forward and reverse directions, and is operated by an electric transmission unit 19. The sub-transmission 14 is configured as a gear transmission type and can be shifted in multiple stages.

[0040] The shift lever 20 is provided in the driver's cab 11, and the operating position of the shift lever 20 is input to the control device 21. The shift lever 20 is operable from the neutral position N1 to the forward side F1 and the reverse side R1. The continuously variable transmission 6 is operated by the control device 21 and the transmission unit 19 so as to be in a transmission position corresponding to the operating position of the shift lever 20.

[0041] The front-wheel transmission 16 is operable between a standard state in which the front wheels 1 and the rear wheels 2 are driven at the same speed and a speed-up state in which the front wheels 1 are driven at a higher speed than the rear wheels 2. When the front wheels 1 are operated by the steering handle 13 within the range of the set angles to the right and left from the straight-ahead position, the front-wheel transmission 16 is operated to the standard state. When the front wheels 1 are steered to the right (left) by the steering handle 13 beyond the set angle to the right (left), the front-wheel transmission 16 is operated to the speed-up state.

[0042] (Configuration of the right and left brakes) As shown in FIG. 2, inside the transmission case 7, a right brake 23 is provided in the transmission system from the rear-wheel differential device 15 to the right rear wheel 2, and a left brake 24 is provided in the transmission system from the rear-wheel differential device 15 to the left rear wheel 2. Braking is applied to the right rear wheel 2 by the right brake 23, and braking is applied to the left rear wheel 2 by the left brake 24.

[0043] As shown in FIGS. 1 and 2, a right brake pedal 25 and a left brake pedal 26 are provided on the right side of the front part of the driver's cab 11. A mechanical linkage mechanism 22 such as a link mechanism is connected across the right brake pedal 25 and the right brake 23, and is connected across the left brake pedal 26 and the left brake 24.

[0044] When the right brake pedal 25 is depressed, the depression operation of the right brake pedal 25 is transmitted to the right brake 23 via the linkage mechanism 22, and the right brake 23 is braked. When the left brake pedal 26 is depressed, the depression operation of the left brake pedal 26 is transmitted to the left brake 24 via the linkage mechanism 22, and the left brake 24 is braked.

[0045] (Configuration of Right and Left Brake Pedals) - 1 As shown in FIGS. 3, 4, and 5, the right and left brake pedals 25, 26 have boss portions 25a, 26a, first arm portions 25b, 26b (corresponding to arm portions) (corresponding to the first part), second arm portions 25c, 26c (corresponding to arm portions) (corresponding to the second part), stepping portions 25d, 26d, and operation arms 25e, 26e (corresponding to the contacted portions).

[0046] The fulcrum shaft 27 is attached to the right part of the clutch housing 5 along the left - right direction. The boss portions 25a, 26a of the brake pedals 25, 26 are attached to the fulcrum shaft 27 so as to be rotatable independently of each other. The first arm portions 25b, 26b of the brake pedals 25, 26 extend forward from the boss portions 25a, 26a.

[0047] The second arm portions 25c, 26c of the brake pedals 25, 26 extend upward from the first arm portions 25b, 26b, come out upward from the opening of the floor 10, and extend to a position higher than the fulcrum shaft 27 (axis P1). The stepping portions 25d, 26d of the brake pedals 25, 26 are attached to the upper portions of the second arm portions 25c, 26c.

[0048] The operation arms 25e, 26e of the brake pedals 25, 26 are attached to the second arm portions 25c, 26c, extend obliquely downward forward, and are arranged in front of (below) the floor 10.

[0049] Thus, the brake pedals 25, 26 are attached to the fulcrum shaft 27 so as to be swingable around the axis P1 (corresponding to the pedal axis) of the fulcrum shaft 27 along the left - right direction. When an operator steps on the stepping portions 25d, 26d of the brake pedals 25, 26, the brake pedals 25, 26 are swung downward (clockwise in FIG. 3), and the brakes 23, 24 are operated for braking.

[0050] The return springs 29 are attached to the boss portions 25a, 26a of the brake pedals 25, 26, and the brake pedals 25, 26 are biased upward (counterclockwise in FIG. 3). When the operator removes their foot from the stepping portions 25d, 26d of the brake pedals 25, 26, the brake pedals 25, 26 are swung upward (counterclockwise in FIG. 3) by the return springs 29 (returned), and the brakes 23, 24 are released.

[0051] The stopper rubber 30 made of hard rubber is attached to the lower surface of the floor 10. When the brake pedals 25, 26 are swung upward (counterclockwise in FIG. 3) by the return springs 29 (returned), the first arm portions 25b, 26b of the brake pedals 25, 26 hit the stopper rubber 30, and the brake pedals 25, 26 are stopped.

[0052] (Correspondence with the claims in the configuration of the right and left brake pedals) The right and left traveling devices (rear wheels 2) and the right and left brakes 23, 24 capable of braking the right and left traveling devices (rear wheels 2) are provided.

[0053] The right and left brake pedals 25, 26 are provided so as to be swingable around a pedal axis (axis P1) along the left - right direction, and have arm portions (first arm portions 25b, 26b and second arm portions 25c, 26c) extending to a position higher than the pedal axis (axis P1), a stepping portion (25d, 26d) attached to the upper part of the arm portions (first arm portions 25b, 26b and second arm portions 25c, 26c), and a contacted portion (operation arms 25e, 26e). By stepping on them, the right and left brakes 23, 24 can be operated for braking.

[0054] The arm portions (the first arm portions 25b, 26b and the second arm portions 25c, 26c) have a first portion (the first arm portions 25b, 26b) that is swingable around the pedal axis (axis P1) and extends forward from the pedal axis (axis P1), and a second portion (the second arm portions 25c, 26c) that extends upward from the front portion of the first portion (the first arm portions 25b, 26b).

[0055] The stepping portions 25d, 26d are attached to the upper portions of the second portions (the second arm portions 25c, 26c). The contacted portions (the operating arms 25e, 26e) extend forward from the second portions (the second arm portions 25c, 26c).

[0056] (Configuration of the right and left brake pedals) - 2 As shown in FIGS. 3 to 6, the fulcrum shaft 32 is connected downward to the first arm portion 25b of the right brake pedal 25, and the connecting member 34 is swingably attached around the axis P3 of the fulcrum shaft 32. A connecting member 35 having a fan shape in side view is connected to the first arm portion 26b of the left brake pedal 26, and a concave portion 35a is provided at the upper and lower central portion of the connecting member 35.

[0057] The state shown in FIGS. 3 to 6 is a state in which the connecting member 34 is operated to be separated forward from the concave portion 35a of the connecting member 35, and the right and left brake pedals 25, 26 can be operated independently of each other by stepping.

[0058] The connecting member 34 is operated rearward from the state shown in FIGS. 3 to 6 and enters the concave portion 35a of the connecting member 35, so that the right and left brake pedals 25, 26 are connected by the connecting members 34, 35.

[0059] In the above state, when one of the stepping portions 25d, 26d of the right and left brake pedals 25, 26 is stepped on, both the right and left brake pedals 25, 26 are swung downward (clockwise in FIG. 3) by the connecting members 34, 35, and both the brakes 23, 24 are braked.

[0060] (Configuration of Right and Left Brake Pedals) - 3 As shown in FIGS. 3 to 6, a serrated engaging member 36 provided with a number of recesses is provided below the floor 10 so as to be swingable around an axis P4 along the left - right direction.

[0061] A holding lever 33 is provided below the steering handle 13 (see FIG. 1), and a linkage rod 44 is connected between the holding lever 33 and the engaging member 36. The engaging member 36 is swing - operated around the axis P4 by the holding lever 33. A flat - plate - shaped engaged portion 45 is attached to the first arm portion 26b of the left brake pedal 26.

[0062] As described above, in a state where the connecting member 34 is inserted into the recess 35a of the connecting member 35 (a state where the right and left brake pedals 25 and 26 are connected), the operator steps on the right and left brake pedals 25 and 26 and operates the holding lever 33 to engage the engaging member 36 with the engaged portion 45. Thereby, the right and left brake pedals 25 and 26 are held in a stepped - on state, and the right and left brakes 23 and 24 exert the function of the parking brake.

[0063] In a state where the right and left brake pedals 25 and 26 are held in a stepped - on state by the holding lever 33, the operator slightly steps on the right and left brake pedals 25 and 26 and operates the holding lever 33 to disengage the engaging member 36 from the engaged portion 45. As a result, the right and left brake pedals 25 and 26 are swing - operated upward (counter - clockwise in FIG. 3) by the return spring 29 (return - operated), and the right and left brakes 23 and 24 are released.

[0064] (Configuration of Right and Left Brake Pedals) - 4 As shown in FIGS. 3 to 6, the operating arm 25e of the right brake pedal 25 is provided from the second arm portion 25c toward the second arm portion 26c of the left brake pedal 26 and extends obliquely downward in the front (see FIGS. 4 and 5).

[0065] The operating arm 26e of the left brake pedal 26 is provided from the second arm portion 26c toward the second arm portion 25c of the right brake pedal 25 and extends obliquely downward forward (see FIGS. 4 and 5).

[0066] As a result, the operating arms 25e and 26e of the right and left brake pedals 25 and 26 are close to each other and are provided between the second arm portions 25c and 26c of the right and left brake pedals 25 and 26 in a front view (see FIG. 5).

[0067] Since the axis P1 of the fulcrum shaft 27 is along the left - right direction, when the right and left brake pedals 25 and 26 are stepped on and released, the operating arms 25e and 26e of the right and left brake pedals 25 and 26 move along the up - down direction.

[0068] (Configuration of the brake sensor for discriminating the stepped - on state of the right and left brake pedals) As shown in FIGS. 3 to 6, the support bracket 28 is attached to the lower part of the right part of the pillar frame 42. A potentiometer - type brake sensor 37 is attached to the support bracket 28, and the brake sensor 37 is close to the operating arms 25e and 26e of the right and left brake pedals 25 and 26.

[0069] The brake sensor 37 has a detection shaft 37a that is rotatable around an axis P2 (corresponding to the detection axis) along the left - right direction. The axis P1 of the fulcrum shaft 27 and the axis P2 of the detection shaft 37a of the brake sensor 37 are parallel.

[0070] A contact portion 38 is provided, and the contact portion 38 has a contact arm 38a and a contact pin 38b. The contact arm 38a of the contact portion 38 is attached to the detection shaft 37a of the brake sensor 37 and extends rearward. As a result, the detection shaft 37a of the brake sensor 37 and the contact portion 38 (contact arm 38a and contact pin 38b) are integrally swingable around the axis P2.

[0071] The brake sensor 37 and the contact portion 38 (contact arm 38a and contact pin 38b) are provided on the right lateral side with respect to the operating arms 25e, 26e of the right and left brake pedals 25, 26 in a plan view.

[0072] The contact pin 38b of the contact portion 38 is attached to the rear end portion (swinging end portion) of the contact arm 38a, extends toward the left, and is positioned above the operating arms 25e, 26e of the right and left brake pedals 25, 26.

[0073] Since the axis P2 of the detection axis 37a of the brake sensor 37 is along the left - right direction, the contact portion 38 (contact arm 38a and contact pin 38b) moves along the up - down direction. As a result, the moving direction (up - down direction) of the operating arms 25e, 26e of the right and left brake pedals 25, 26 and the moving direction (up - down direction) of the contact portion 38 (contact arm 38a and contact pin 38b) are along each other.

[0074] A spring (not shown) installed inside the brake sensor 37 biases the detection axis 37a of the brake sensor 37 to rotate in the clockwise direction in FIG. 6. Thereby, the contact arm 38a of the contact portion 38 is biased downward (clockwise direction in FIG. 6), and the contact pin 38b of the contact portion 38 can contact both of the operating arms 25e, 26e of the right and left brake pedals 25, 26.

[0075] The stopper portion 39 is attached to the lower part of the rear portion of the support bracket 28. When the contact arm 38a of the contact portion 38 swings downward (clockwise direction in FIG. 6), the contact arm 38a of the contact portion 38 is stopped by hitting the stopper portion 39. The stopper portion 39 is set to be short, and the operating arms 25e, 26e of the right and left brake pedals 25, 26 do not contact the stopper portion 39.

[0076] (Correspondence with Claims in the Brake Sensor and Contact Portion) It is provided so as to be movable along the moving direction of the contacted parts (operation arms 25e, 26e) by the stepping operation and the return operation of the brake pedals 25, 26, and is provided with a contact part 38 that can contact the contacted parts (operation arms 25e, 26e) of both the right and left brake pedals 25, 26.

[0077] It is provided with a brake sensor 37 that can detect the movement of the contact part 38. The contact part 38 is provided at a position where the contacted part (operation arm 25e, 26e) moves in a direction away from the contact part 38 by the stepping operation of the brake pedals 25, 26, and is biased in the moving direction of the contacted part (operation arm 25e, 26e) by the stepping operation of the brake pedals 25, 26.

[0078] The brake sensor 37 has a detection shaft 37a that can rotate around the detection axis (axis P2), and a contact arm 38a is attached to the detection shaft 37a. It is provided with a stopper part 39 that stops the follow-up of the contact part 38 to the contacted parts (operation arms 25e, 26e) at a preset predetermined position.

[0079] The contact part 38 has a contact arm 38a that can swing around a detection axis (axis P2) along the left-right direction, and a contact pin 38b that is provided at the swinging end of the contact arm 38a and can contact the contacted parts (operation arms 25e, 26e) of both the right and left brake pedals 25, 26.

[0080] The contacted part (operation arm 25e, 26e) of at least one of the right and left brake pedals 25, 26 is formed toward the other contacted part (operation arm 25e, 26e), and the contacted parts (operation arms 25e, 26e) of both the right and left brake pedals 25, 26 are provided close to each other.

[0081] The contact arm 38a is provided on the right or left lateral side with respect to the contacted parts (operation arms 25e, 26e) of the right and left brake pedals 25, 26. The contact pin 38b extends from the swing end of the contact arm 38a toward the contact portions (operation arms 25e, 26e) of the right and left brake pedals 25, 26, and can contact the contact portions (operation arms 25e, 26e) of both the right and left brake pedals 25, 26.

[0082] The contact portion (operation arm 25e) of the right brake pedal 25 is formed toward the contact portion (operation arm 26e) of the left brake pedal 26. The contact portion (operation arm 26e) of the left brake pedal 26 is formed toward the contact portion (operation arm 25e) of the right brake pedal 25. The contact portions (operation arms 25e, 26e) of the right and left brake pedals 25, 26 are provided between the right and left brake pedals 25, 26 in a front view.

[0083] (Discrimination state of the stepping operations of the right and left brake pedals by the brake sensor) - 1 The state shown in #1 of FIG. 7 is a state where the right and left brake pedals 25, 26 are returned (not stepped on).

[0084] In the state shown in #1 of FIG. 7, the operation arms 25e, 26e of the right and left brake pedals 25, 26 are located at the same position (see FIGS. 3 to 6). The contact pin 38b of the contact portion 38 contacts both operation arms 25e, 26e of the right and left brake pedals 25, 26 and is stopped, and the contact arm 38a (detection axis 37a of the brake sensor 37) of the contact portion 38 is located at the first position A1.

[0085] In the state shown in #1 of FIG. 7, when the right brake pedal 25 is stepped on, as shown in #2 of FIG. 7, the operation arm 25e of the right brake pedal 25 moves downward. Since the left brake pedal 26 is not stepped on, the operation arm 26e of the left brake pedal 26 remains at the position shown in #1 of FIG. 7 (see FIGS. 3 to 6).

[0086] When the contact pin 38b of the contact portion 38 contacts and is stopped by the operation arm 26e of the left brake pedal 26, the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) is located at the first position A1.

[0087] When the left brake pedal 26 is depressed, the operation arm 25e of the non-depressed right brake pedal 25 remains at the position shown by #1 in FIG. 7 (see FIGS. 3 to 6). When the contact pin 38b of the contact portion 38 contacts and is stopped by the operation arm 25e of the right brake pedal 25, the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) is located at the first position A1.

[0088] When the operator removes their foot from the depressed portions 25d and 26d of the brake pedals 25 and 26 from the state shown by #2 in FIG. 7, the brake pedals 25 and 26 are swing-operated upward (counterclockwise in FIG. 3) by the return springs 29 (return operation). The operation arms 25e and 26e of the brake pedals 25 and 26 move upward and return to the position shown by #1 in FIG. 7 (see FIGS. 3 to 6).

[0089] (Discrimination state of the depression operations of the right and left brake pedals by the brake sensor) - 2 As shown in #3 in FIG. 7 from the state shown in #1 in FIG. 7, when both the right and left brake pedals 25 and 26 are depressed, the operation arms 25e and 26e of both the right and left brake pedals 25 and 26 move downward.

[0090] When the operation arms 25e and 26e of both the right and left brake pedals 25 and 26 move downward, the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) swings downward (clockwise in FIG. 6) from the first position A1 so as to follow while contacting the operation arms 25e and 26e of both the right and left brake pedals 25 and 26.

[0091] As shown in #4 of FIG. 7, when the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) reaches the second position A2, the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) hits the stopper portion 39 and is stopped, and cannot swing downward (clockwise in FIG. 6) beyond the second position A2.

[0092] When both the right and left brake pedals 25, 26 are further depressed, the operating arms 25e, 26e of both the right and left brake pedals 25, 26 move downward away from the contact pins 38b of the contact portion 38.

[0093] When the operator releases his / her feet from the stepping portions 25d, 26d of the brake pedals 25, 26 in the state shown in #4 of FIG. 7, both the right and left brake pedals 25, 26 are swing-operated (return-operated) upward (counterclockwise in FIG. 3) by the return springs 29.

[0094] As a result, the operating arms 25e, 26e of both the right and left brake pedals 25, 26 move upward and come into contact with the contact pin 38b of the contact portion 38 at the second position A2, and while pushing the contact pin 38b of the contact portion 38 upward, return to the position shown in #1 of FIG. 7 (see FIGS. 3 to 6).

[0095] The contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) is returned from the second position A2 to the first position A1 by the operating arms 25e, 26e of both the right and left brake pedals 25, 26.

[0096] (Correspondence with claims in the discrimination state of the stepping operation of the right and left brake pedals by the brake sensor) When one of the right and left brake pedals 25, 26 is depressed, the contact portion 38 comes into contact with and is stopped by the other contact portion (operating arms 25e, 26e) of the right and left brake pedals 25, 26, so that the contact portion 38 does not follow the movement of the other contact portion (operating arms 25e, 26e) of one of the right and left brake pedals 25, 26.

[0097] When both the right and left brake pedals 25 and 26 are depressed, the contact portion 38 moves following the movement of the contact portions (operation arms 25e and 26e) of both the right and left brake pedals 25 and 26, and thus it is detected by the brake sensor 37 that both the right and left brake pedals 25 and 26 have been depressed.

[0098] (Operation based on detection of brake sensor) - 1 As shown in FIGS. 2 and 7, the detection value of the brake sensor 37 due to the swing of the contact arm 38a (detection axis 37a of the brake sensor 37) of the contact portion 38 over the first position A1 and the second position A2 is input to the control device 21. For example, assume that the shift lever 20 is operated to the highest speed position on the forward side F1, and the continuously variable transmission 6 is operated to the highest speed position on the forward side F1 by the control device 21 and the transmission unit 19.

[0099] In the above state, as shown from #1 in FIG. 7 to #2 in FIG. 7, when the right brake pedal 25 is depressed, the operation arm 26e of the non-depressed left brake pedal 26 remains at the position shown in #1 in FIG. 7. Since the contact pin 38b of the contact portion 38 contacts and is stopped by the operation arm 26e of the left brake pedal 26, the contact arm 38a (detection axis 37a of the brake sensor 37) of the contact portion 38 does not move from the first position A1.

[0100] When the left brake pedal 26 is depressed, the operation arm 25e of the non-depressed right brake pedal 25 remains at the position shown in #1 in FIG. 7. Since the contact pin 38b of the contact portion 38 contacts and is stopped by the operation arm 25e of the right brake pedal 25, the contact arm 38a (detection axis 37a of the brake sensor 37) of the contact portion 38 does not move from the first position A1.

[0101] As a result, the brake sensor 37 does not detect the state where both the right and left brake pedals 25 and 26 are depressed, so the continuously variable transmission 6 is maintained at the highest speed position on the forward side F1 corresponding to the operation position of the shift lever 20.

[0102] (Operation Based on Detection of Brake Sensor) - 2 For example, assume that the shift lever 20 is operated to the highest speed position on the forward side F1, and the continuously variable transmission 6 is operated to the highest speed position on the forward side F1 by the control device 21 and the transmission unit 19.

[0103] In the above state, as shown in #1 to #3 and #4 of FIG. 7, both the right and left brake pedals 25 and 26 start to be depressed, and the contact arm 38a of the contact portion 38 (the detection shaft 37a of the brake sensor 37) starts to move from the first position A1 toward the second position A2.

[0104] When the contact arm 38a of the contact portion 38 (the detection shaft 37a of the brake sensor 37) starts to move from the first position A1 toward the second position A2, the brake sensor 37 will detect that both the right and left brake pedals 25 and 26 are in the depressed state. As a result, the continuously variable transmission 6 starts to be operated from the highest speed position on the forward side F1 to the low speed side by the control device 21 and the transmission unit 19.

[0105] As both the right and left brake pedals 25 and 26 are depressed and the contact arm 38a of the contact portion 38 (the detection shaft 37a of the brake sensor 37) approaches the second position A2, the continuously variable transmission 6 is more greatly operated to the low speed side by the control device 21 and the transmission unit 19.

[0106] In this case, since there is mechanical play in the linkage mechanism 22 and the brakes 23 and 24, during the above period, even if the right and left brake pedals 25 and 26 are depressed, the brakes 23 and 24 are not actually braked yet.

[0107] Until the contact arm 38a of the contact portion 38 (the detection shaft 37a of the brake sensor 37) reaches the second position A2, when both the right and left brake pedals 25 and 26 are depressed, the above-mentioned mechanical play disappears, so the brakes 23 and 24 actually start to be braked.

[0108] At the same time, the operation of the continuously variable transmission 6 to the low-speed side by the control device 21 and the transmission unit 19 is stopped. When both the right and left brake pedals 25 and 26 are further depressed, the brakes 23 and 24 are operated for braking, and the airframe 3 stops.

[0109] (Operation based on detection by brake sensor) - 3 As described above, when the contact arm 38a of the contact portion 38 (the detection shaft 37a of the brake sensor 37) is located at the first position A1, the continuously variable transmission 6 is operated to a shift position corresponding to the operation position of the shift lever 20.

[0110] When the contact arm 38a of the contact portion 38 (the detection shaft 37a of the brake sensor 37) is located at the second position A2, the continuously variable transmission 6 is operated from the shift position corresponding to the operation position of the shift lever 20 to a slightly lower-speed shift position.

[0111] When the contact arm 38a of the contact portion 38 (the detection shaft 37a of the brake sensor 37) is in the range extending between the first position A1 and the second position A2, the operator can operate the continuously variable transmission 6 between the shift position corresponding to the operation position of the shift lever 20 and a shift position slightly lower than this shift position without braking the brakes 23 and 24 by depressing or releasing both the right and left brake pedals 25 and 26.

[0112] (First alternative embodiment of the invention) When the operating arms 25e and 26e of the right and left brake pedals 25 and 26 extend straight forward from the second arm portions 25c and 26c, they may be configured as described below.

[0113] As shown in FIGS. 8 and 9, the fulcrum portion 46 is provided separately from the brake sensor 37, and the contact arm 38a of the contact portion 38 is attached to the fulcrum portion 46 so as to be swingable up and down around the axis P2. The contact arm 38a of the contact portion 38 extends rearward from the fulcrum portion 46 and is disposed between the operating arms 25e and 26e of the right and left brake pedals 25 and 26 in plan view.

[0114] The contact pins 38b of the contact portion 38 extend rightward and leftward from the rear end portion (swinging end portion) of the contact arm 38a of the contact portion 38 and contact the upper portions of the operating arms 25e and 26e of the right and left brake pedals 25 and 26.

[0115] In the brake sensor 37, the detection arm 47 is attached to the detection shaft 37a of the brake sensor 37 and extends rearward, and the pin 47a at the rear end portion (swinging end portion) of the detection arm 47 contacts the upper portion of the contact arm 38a of the contact portion 38.

[0116] A spring (not shown) installed inside the brake sensor 37 biases the detection shaft 37a and the detection arm 47 of the brake sensor 37 to rotate downward (counterclockwise in FIG. 9). Through the detection shaft 37a and the detection arm 47 of the brake sensor 37, the contact arm 38a of the contact portion 38 is biased downward (counterclockwise in FIG. 9). In the configurations shown in FIGS. 8 and 9, the discrimination of the stepping operations of the right and left brake pedals 25 and 26 by the brake sensor 37 is the same as that in FIG. 7.

[0117] In the configurations shown in FIGS. 8 and 9, the position of the axis P2 of the contact portion 38 and the position of the detection shaft 37a of the brake sensor 37 may be arranged at different positions in a side view (see FIG. 9). The detection arm 47 may be abolished, and the contact arm 38a of the contact portion 38 may be attached to the detection shaft 37a of the brake sensor 37.

[0118] (Correspondence with Claims in Brake Sensor and Contact Portion) The contact portion 38 is swingable around a detection axis (axis P2) along the left - right direction, and has a contact arm 38a provided between the contacted portions (operating arms 25e and 26e) of the right and left brake pedals 25 and 26 in a plan view, and contact pins 38b provided at the swinging end portion of the contact arm 38a, extending rightward and leftward from the contact arm 38a and capable of contacting both of the contacted portions (operating arms 25e and 26e) of the right and left brake pedals 25 and 26.

[0119] (Second Alternative Embodiment of the Invention) In the right and left brake pedals 25 and 26, the operating arm 25e of the right brake pedal 25 extends straight forward from the second arm portion 25c, and the operating arm 26e of the left brake pedal 26 extends from the second arm portion 26c toward the second arm portion 25c of the right brake pedal 25 and extends forward, so that the operating arms 25e and 26e of the right and left brake pedals 25 and 26 may be configured to be close to each other. According to this configuration, the brake sensor 37 and the contact portion 38 may be provided on the left side with respect to the operating arm 26e of the left brake pedal 26.

[0120] (Third Alternative Embodiment of the Invention) In the right and left brake pedals 25 and 26, the operating arm 26e of the left brake pedal 26 extends straight forward from the second arm portion 26c, and the operating arm 25e of the right brake pedal 25 extends from the second arm portion 25c toward the second arm portion 26c of the left brake pedal 26 and extends forward, so that the operating arms 25e and 26e of the right and left brake pedals 25 and 26 may be configured to be close to each other. According to this configuration, the brake sensor 37 and the contact portion 38 may be provided on the right side with respect to the operating arm 25e of the right brake pedal 25.

[0121] (Fourth Alternative Embodiment of the Invention) When the operating arms 25e and 26e of the brake pedals 25 and 26 are abolished, the brake sensor 37 and the contact portion 38 may be provided below the floor 10 above the first arm portions 25b and 26b of the right and left brake pedals 25 and 26.

[0122] According to the above-described configuration, the contact pin 38b of the contact portion 38 contacts both of the first arm portions 25b and 26b of the right and left brake pedals 25 and 26. When the brake pedals 25 and 26 are depressed and the first arm portions 25b and 26b of the brake pedals 25 and 26 move downward, the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) may be configured to be biased downward and follow the first arm portions 25b and 26b of the brake pedals 25 and 26. According to the above-described configuration, the first arm portions 25b and 26b of the brake pedals 25 and 26 serve as the contacted portions.

[0123] (Fifth Alternative Embodiment of the Invention) The operating arms 25e and 26e of the brake pedals 25 and 26 may be attached to the first arm portions 25b and 26b and extend forward.

[0124] (Sixth Alternative Embodiment of the Invention) The contact portion 38 may be configured to move linearly across the first position A1 and the second position A2 instead of swinging around the axis P2. According to this configuration, a spring (not shown) that biases the contact portion 38 to the second position A2 may be attached to the contact portion 38.

[0125] (Seventh Alternative Embodiment of the Invention) As control based on the detection of the brake sensor 37, control as described below may be performed.

[0126] In the continuously variable transmission 6, the transmission unit 19 is abolished, and a transmission pedal (not shown) and the continuously variable transmission 6 are connected via a link mechanism (not shown). An urging mechanism (not shown) that urges the transmission pedal to the neutral position N1 is provided, and the operator depresses the transmission pedal against the urging mechanism to operate the continuously variable transmission 6.

[0127] A holding mechanism is provided that can hold the transmission pedal at a desired operating position against the urging mechanism. The operator depresses the transmission pedal to a desired operating position and holds the transmission pedal by the holding mechanism, so that the vehicle body 3 can travel at a desired speed even when the operator removes their foot from the transmission pedal.

[0128] In the above configuration, when the brake sensors 37 detect that both the right and left brake pedals 25 and 26 have been depressed, the holding mechanism is released. As a result, the shift pedal returns to the neutral position N1 by the biasing mechanism, and the continuously variable transmission 6 is operated to the neutral position N1, reducing the load applied to the brakes 23 and 24.

Industrial Applicability

[0129] The present invention can be applied not only to a work vehicle equipped with front wheels 1 and rear wheels 2, but also to a work vehicle equipped with front wheels 1 and a rear crawler traveling device (equivalent to a traveling device), and can also be applied to a work vehicle equipped with right and left crawler traveling devices without front wheels 1 and rear wheels 2.

Explanation of Reference Numerals

[0130] 2 Rear wheels (traveling device) 23 Brake 24 Brake 25 Brake pedal 25b First arm portion (arm portion) (first part) 25c Second arm portion (arm portion) (second part) 25d Step portion 25e Operating arm (contacted portion) 26 Brake pedal 26b First arm portion (arm portion) (first part) 26c Second arm portion (arm portion) (second part) 26d Step portion 26e Operating arm (contacted portion) 37 Brake sensor 37a Detection shaft 38 Contact portion 38a Contact arm 38b Contact pin 39 Stopper portion P1 Axis (pedal axis) P2 Axis (detection axis)

Claims

1. Right and left traveling devices, Right and left brakes capable of braking the right and left traveling devices, An arm portion provided so as to be swingable around a pedal axis along the left - right direction and extending to a position higher than the pedal axis, a stepping portion attached to the upper portion of the arm portion, and a contact portion, and having a right and left brake pedal capable of braking - operating the right and left brakes by being stepped on, A contact portion provided so as to be movable along the moving direction of the contact portion by the stepping operation and the returning operation of the brake pedal and capable of contacting the contact portions of both the right and left brake pedals, A brake sensor capable of detecting the movement of the contact portion is provided, The contact portion is provided at a position where the contact portion moves away from the contact portion in a direction when the brake pedal is stepped on, and is biased in the moving direction of the contact portion by the stepping operation of the brake pedal, When one of the right and left brake pedals is stepped on, the contact portion contacts and stops at the contact portion of the other of the right and left brake pedals, so that the contact portion does not follow the movement of the contact portion of one of the right and left brake pedals, When both the right and left brake pedals are stepped on, the contact portion moves following the movement of the contact portions of both the right and left brake pedals, and a work vehicle in which it is detected by the brake sensor that both the right and left brake pedals have been stepped on.

2. The arm portion has a first portion swingable around the pedal axis and extending forward from the pedal axis, and a second portion extending upward from the front portion of the first portion, The stepping portion is attached to the upper portion of the second portion, The work vehicle according to claim 1, wherein the contact portion extends forward from the second portion.

3. The work vehicle according to claim 1, wherein the contact portion has a contact arm swingable around a detection axis along the left - right direction, and a contact pin provided at a swing end portion of the contact arm and capable of contacting the contact portions of both the right and left brake pedals.

4. The brake sensor has a detection shaft rotatable around the detection axis, The work vehicle according to claim 3, wherein the contact arm is attached to the detection shaft.

5. At least one of the contact portions of the right and left brake pedals is formed toward the other contact portion, and the contact portions of both the right and left brake pedals are provided close to each other. The contact arm is provided on the right or left lateral side with respect to the contact portions of the right and left brake pedals. The working vehicle according to claim 3, wherein the contact pin extends from the swing end portion of the contact arm toward the contact portions of the right and left brake pedals and can contact the contact portions of both the right and left brake pedals.

6. The contact portion of the right brake pedal is formed toward the contact portion of the left brake pedal. The contact portion of the left brake pedal is formed toward the contact portion of the right brake pedal. The working vehicle according to claim 5, wherein the contact portions of the right and left brake pedals are provided between the right and left brake pedals in a front view.

7. The contact portion is swingable around a detection axis along the left - right direction and includes a contact arm provided between the contact portions of the right and left brake pedals in a plan view, and a contact pin provided at the swing end portion of the contact arm and extending rightward and leftward from the contact arm and capable of contacting the contact portions of both the right and left brake pedals. The working vehicle according to claim 2.

8. The working vehicle according to claim 1, further comprising a stopper portion that stops the follow - up of the contact portion to the contact portion at a preset predetermined position.

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