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 parts 25d and 26d by operation of stepping-on and operation of returning brake pedals 25 and 26, and can contact both parts to be contacted 25d and 26d, 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 25d and 26d move 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 25d and 26d by operation of stepping-on the brake pedals 25 and 26.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a work vehicle provided 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 these various operations is shown below.

[0004] When the traveling transmission 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 traveling transmission is released, and the traveling transmission 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 traveling transmission 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 one 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 one brake sensor.

[0009] The present invention aims to simplify the configuration for determining the state of the depression operation of the right and left brake pedals with one 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, a pedal shaft core provided swingably around a pedal shaft core along the left - right direction, an arm portion extending downward from the pedal shaft core, a stepping portion attached to the lower portion of the arm portion, and a contacted portion. It has right and left brake pedals capable of braking - operating the right and left brakes by being stepped on, a contact portion provided movably along the moving direction of the contacted portion by stepping on and returning the brake pedals, and capable of contacting the contacted portions of both 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 contacted portion moves in a direction away from the contact portion by stepping on the brake pedal, and is biased in the moving direction of the contacted 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 contacted portion of the other of the right and left brake pedals, so that the contact portion does not follow the movement of the contacted 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 contacted portions of both the right and left brake pedals, and the fact that both 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 contacted portions of the right and left brake pedals and contacts and stops at the contacted 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 contacted 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 contacted 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 in which 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 nothing 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. When the contact portion moves, the brake sensor detects a state in which 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 contacted portion extends upward higher than the pedal axis, and the brake sensor and the contact portion are provided at a position higher than the pedal axis.

[0017] According to the present invention, in a brake pedal having an arm portion extending downward from the pedal axis and a stepped portion attached to the lower portion of the arm portion, the contacted portion extends upward higher than the pedal axis, and the brake sensor and the contact portion are provided at a position higher than the pedal axis.

[0018] 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. Since the brake sensor and the contact portion are provided at a relatively high position, it is possible to reduce the adhesion of mud and the like to the brake sensor and the contact portion, and it is possible to reduce the malfunction of the brake sensor and the contact portion.

[0019] 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 the swing end portion of the contact arm and capable of contacting the contacted portions of both the right and left brake pedals.

[0020] 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.

[0021] In the present invention, it is preferable that the brake sensor has a detection shaft rotatable around the detection axis, and the contact arm is attached to the detection shaft.

[0022] According to the present invention, when the brake sensor has a detection shaft rotatable around the detection axis, by attaching the contact arm of the contact portion to the detection shaft 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.

[0023] 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.

[0024] 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.

[0025] In the present invention, it is preferable that a stopper portion is provided for stopping the follow-up of the contact portion to the contact portion at a predetermined position set in advance.

[0026] 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 contact portions of the right and left brake pedals, when the contact portion has moved by a necessary length, it is stopped by the stopper portion, and the position of the stopper portion may be set so that the contact 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 contact 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

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0028] Figs. 1 to 6 show a tractor which is an example of a work vehicle. In Figs. 1 to 6, 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.

[0029] (Overall Configuration of the Tractor) As shown in Fig. 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. The driver's cab 11 is provided on the machine body 3, and the driver's seat 12 and the steering wheel 13 for steering the front wheels 1 are provided in the driver's cab 11. The driver's cab 11 is covered by the cab 10.

[0030] The machine body 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 at the right and left parts of the front axle case 9. The rear wheels 2 are provided at the right and left parts of the rear part of the transmission case 7.

[0031] (Transmission Configuration of the Traveling System) As shown in Fig. 2, the auxiliary 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 then transmitted from the auxiliary transmission 14 through the rear-wheel differential device 15 to the right and left rear wheels 2.

[0032] The power branched between the auxiliary transmission 14 and the rear-wheel differential device 15 is transmitted to the front-wheel transmission 16, and from the transmission shaft 17, it is transmitted to the right and left front wheels 1 through the front-wheel differential device 18 provided inside the front axle case 9.

[0033] The continuously variable transmission 6 is configured hydraulically and can continuously shift the power of the engine 4 in the forward and reverse directions, and is operated by the electric transmission unit 19. The auxiliary transmission 14 is configured as a gear transmission and can be shifted in multiple stages.

[0034] The shift lever 20 is provided on the operation unit 11, and the operation position of the shift lever 20 is input to the control device 21. The shift lever 20 can be operated 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 shift position corresponding to the operation position of the shift lever 20.

[0035] The front-wheel transmission 16 can be operated 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 within the range of the set angles to the right and left from the straight-ahead position by the steering handle 13, the front-wheel transmission 16 is operated in the standard state. When the front wheels 1 are steered to the right (left) beyond the set angle to the right (left) by the steering handle 13, the front-wheel transmission 16 is operated in the speed-up state.

[0036] (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. The right brake 23 applies braking to the right rear wheel 2, and the left brake 24 applies braking to the left rear wheel 2.

[0037] 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 section 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.

[0038] 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.

[0039] (Configuration of the right and left brake pedals) - 1 As shown in FIGS. 3, 4, and 5, a support bracket 28 is attached to the right side of the front part of the driver's section 11, and a fulcrum shaft 27 is attached to the support bracket 28 along the left - right direction.

[0040] The right and left brake pedals 25, 26 have boss portions 25a, 26a, arm portions 25b, 26b, step portions 25c, 26c, and operation arms 25d, 26d (corresponding to the contacted portions).

[0041] 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 arm portions 25b, 26b of the brake pedals 25, 26 extend downward from the boss portions 25a, 26a, and the step portions 25c, 26c of the brake pedals 25, 26 are attached to the lower portions of the arm portions 25b, 26b.

[0042] The operating arms 25d, 26d of the brake pedals 25, 26 are attached to the boss portions 25a, 26a and extend upward. The operating arms 25d, 26d of the brake pedals 25, 26 are attached to the arm portions 25b, 26b via the boss portions 25a, 26a.

[0043] As a result, the brake pedals 25, 26 are attached to the fulcrum shaft 27 so as to be swingable about the axis P1 (corresponding to the pedal axis) of the fulcrum shaft 27 along the left - right direction. When the operator steps on the stepping portions 25c, 26c of the brake pedals 25, 26, the brake pedals 25, 26 are swing - operated forward (clockwise in FIG. 4), and the brakes 23, 24 are brake - operated.

[0044] The return spring 29 is attached across the boss portions 25a, 26a and the arm portions 25b, 26b of the brake pedals 25, 26, and the brake pedals 25, 26 are biased rearward (counter - clockwise in FIG. 4).

[0045] When the operator removes the feet from the stepping portions 25c, 26c of the brake pedals 25, 26, the brake pedals 25, 26 are swing - operated rearward (counter - clockwise in FIG. 4) (return - operated) by the return spring 29, and the brakes 23, 24 are released.

[0046] (Correspondence with 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.

[0047] The right and left brake pedals 25 and 26 are provided so as to be swingable around a pedal axis (axis P1) along the left-right direction, and include arm portions 25b and 26b extending downward from the pedal axis (axis P1), step portions 25c and 26c attached to the lower portions of the arm portions 25b and 26b, and contact portions (operating arms 25d and 26d). By stepping on the pedals, the right and left brakes 23 and 24 can be brake-operated.

[0048] (Configuration of Right and Left Brake Pedals) - 2 As shown in FIGS. 3, 4, and 5, a bracket 30 is connected to the arm portion 26b of the left brake pedal 26, and a channel-shaped connecting member 31 is attached to the bracket 30 so as to be swingable around an axis P3 along the front-rear direction in a plan view.

[0049] The state shown in FIGS. 3, 4, and 5 is a state in which the connecting member 31 is released from the arm portion 25b of the right brake pedal 25, and the right and left brake pedals 25 and 26 can be stepped on independently of each other.

[0050] The connecting member 31 can be operated to a position where it engages with the arm portion 25b of the right brake pedal 25 by being operated downward from the state shown by the solid line in FIG. 3 (see the broken line in FIG. 3). In this state, the right and left brake pedals 25 and 26 are connected.

[0051] In the above state, when one of the step portions 25c and 26c of the right and left brake pedals 25 and 26 is stepped on, both the right and left brake pedals 25 and 26 are swing-operated forward (clockwise in FIG. 4) by the connecting member 31, and both the brakes 23 and 24 are brake-operated.

[0052] (Configuration of Right and Left Brake Pedals) - 3 As shown in FIGS. 3, 4, and 5, the fulcrum shaft 32 is attached to the support bracket 28 along the left - right direction, and the holding lever 33 is swingably attached to the fulcrum shaft 32. An arm portion 33a is attached to the holding lever 33, and an engaging portion 33b is attached to the end of the arm portion 33a.

[0053] The holding lever 33 (arm portion 33a and engaging portion 33b) is swingable around the axis P4 of the fulcrum shaft 32 along the left - right direction. A return spring 34 is attached to the holding lever 33, and the holding lever 33 is biased downward (clockwise in FIG. 4) by the return spring 34. An arm 35 is attached to the arm portion 26b of the left brake pedal 26, and a serrated engaged portion 36 provided with a number of recesses is attached to the arm 35.

[0054] As described above, in a state where the connecting member 31 is operated to a position where it engages with the arm portion 25b of the right brake pedal 25 (see the dashed line in FIG. 3) (a state where the right and left brake pedals 25 and 26 are connected), after the right and left brake pedals 25 and 26 are stepped on, when the holding lever 33 is operated upward from the position shown in FIG. 4, the engaging portion 33b of the holding lever 33 moves downward and engages with the engaged portion 36 of the left brake pedal 26. 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 perform the function of the parking brake.

[0055] In a state where the right and left brake pedals 25 and 26 are held in a state of being stepped on by the holding lever 33, when the right and left brake pedals 25 and 26 are stepped on, the engaged portion 36 of the left brake pedal 26 moves slightly forward and disengages from the engaging portion 33b of the holding lever 33. Therefore, the holding lever 33 returns to the position shown in FIG. 4 by the return spring 34, and the engaging portion 33b of the holding lever 33 moves upward and away from the engaged portion 36 of the left brake pedal 26.

[0056] As a result, the right and left brake pedals 25, 26 are swung rearward (counterclockwise in FIG. 4) by the return springs 29 (returned), and the right and left brakes 23, 24 are released.

[0057] (Configuration of Right and Left Brake Pedals) - 4 As shown in FIGS. 3, 4, and 5, the operating arm 25d of the right brake pedal 25 is bent from the boss portion 25a toward the boss portion 26a of the left brake pedal 26 and extends upward.

[0058] The operating arm 26d of the left brake pedal 26 is bent from the boss portion 26a toward the boss portion 25a of the right brake pedal 25 and extends upward. As a result, the operating arms 25d, 26d of the right and left brake pedals 25, 26 are close to each other.

[0059] Since the axis P1 of the fulcrum shaft 27 is along the left - right direction, when the right and left brake pedals 25, 26 are depressed and returned, the operating arms 25d, 26d of the right and left brake pedals 25, 26 move along the front - rear direction.

[0060] (Configuration of Brake Sensor for Determining the Depressed State of Right and Left Brake Pedals) As shown in FIGS. 3, 4, and 5, the upper part of the support bracket 28 extends upward from the fulcrum shaft 27, is bent toward the operating arm 25d of the right brake pedal 25, and extends upward. As a result, the upper part of the support bracket 28 is close to the operating arm 25d of the right brake pedal 25.

[0061] A potentiometer-type brake sensor 37 is attached to the upper part of the support bracket 28, and the brake sensor 37 is close to the operating arms 25d, 26d of the right and left brake pedals 25, 26. 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, and the axis P1 of the fulcrum shaft 27 is parallel to the axis P2 of the detection shaft 37a of the brake sensor 37.

[0062] 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 upward. Thus, the detection shaft 37a of the brake sensor 37 and the contact portion 38 (the contact arm 38a and the contact pin 38b) are integrally swingable around the axis P2.

[0063] The brake sensor 37 and the contact portion 38 (the contact arm 38a and the contact pin 38b) are provided on the right lateral side with respect to the operating arms 25d, 26d of the right and left brake pedals 25, 26 in a front view (rear view).

[0064] The contact pin 38b of the contact portion 38 is attached to the upper end portion (swing end portion) of the contact arm 38a and extends leftward, and is positioned in front of the operating arms 25d, 26d of the right and left brake pedals 25, 26.

[0065] Since the axis P2 of the detection shaft 37a of the brake sensor 37 is along the left-right direction, the contact portion 38 (the contact arm 38a and the contact pin 38b) moves along the front-rear direction. Thus, the moving direction (front-rear direction) of the operating arms 25d, 26d of the right and left brake pedals 25, 26 and the moving direction (front-rear direction) of the contact portion 38 (the contact arm 38a and the contact pin 38b) are along each other.

[0066] A spring (not shown) installed in the brake sensor 37 biases the detection axis 37a of the brake sensor 37 to rotate in the clockwise direction in FIG. 4. As a result, the contact arm 38a of the contact portion 38 is biased rearward (in the clockwise direction in FIG. 4), and the contact pin 38b of the contact portion 38 can contact both the operation arms 25d and 26d of the right and left brake pedals 25 and 26.

[0067] The stopper portion 39 is attached to the rear part of the upper portion of the support bracket 28. When the contact arm 38a of the contact portion 38 swings rearward (in the clockwise direction in FIG. 4), 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 operation arms 25d and 26d of the right and left brake pedals 25 and 26 do not contact the stopper portion 39.

[0068] (Correspondence with claims in the brake sensor and the contact portion) A contact portion 38 is provided so as to be movable along the moving direction of the contacted portions (operation arms 25d and 26d) by the stepping operation and the return operation of the brake pedals 25 and 26, and can contact both the contacted portions (operation arms 25d and 26d) of the right and left brake pedals 25 and 26.

[0069] A brake sensor 37 capable of detecting the movement of the contact portion 38 is provided. The contact portion 38 is provided at a position where the contacted portion (operation arms 25d and 26d) moves away from the contact portion 38 by the stepping operation of the brake pedals 25 and 26, and is biased in the moving direction of the contacted portion (operation arms 25d and 26d) by the stepping operation of the brake pedals 25 and 26.

[0070] The brake sensor 37 has a detection axis 37a that can rotate around a detection axis center (axis P2), and the contact arm 38a is attached to the detection axis 37a. A stopper portion 39 is provided to stop the follow-up of the contact portion 38 to the contacted portion (operation arms 25d and 26d) at a predetermined position set in advance.

[0071] The contacted part extends upward higher than the (operation arms 25d, 26d) and the pedal axis (axis P1). The brake sensor 37 and the contact part 38 are provided at a position higher than the pedal axis (axis P1).

[0072] The contact part 38 has a contact arm 38a swingable around a detection axis (axis P2) along the left - right direction, and a contact pin 38b provided at the swing end of the contact arm 38a and capable of contacting the contacted parts (operation arms 25d, 26d) of both the right and left brake pedals 25, 26.

[0073] The contacted part (operation arms 25d, 26d) of at least one of the right and left brake pedals 25, 26 is formed toward the contacted part (operation arms 25d, 26d) of the other, and the contacted parts (operation arms 25d, 26d) of both the right and left brake pedals 25, 26 are provided close to each other.

[0074] The contact arm 38a is provided on the right or left lateral side with respect to the contacted parts (operation arms 25d, 26d) 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 contacted parts (operation arms 25d, 26d) of the right and left brake pedals 25, 26 and is capable of contacting the contacted parts (operation arms 25d, 26d) of both the right and left brake pedals 25, 26.

[0075] (Determination state of the stepping operations of the right and left brake pedals by the brake sensor) - 1 The state shown in #1 of Fig. 6 is a state where the right and left brake pedals 25, 26 are returned (not stepped on).

[0076] In the state shown in #1 of FIG. 6, the operating arms 25d and 26d of the right and left brake pedals 25 and 26 are located at the same position (see FIGS. 3, 4, and 5). The contact pin 38b of the contact portion 38 contacts both the operating arms 25d and 26d of the right and left brake pedals 25 and 26 and is stopped, and 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.

[0077] In the state shown in #1 of FIG. 6, when the right brake pedal 25 is depressed, as shown in #2 of FIG. 6, the operating arm 25d of the right brake pedal 25 moves backward. Since the left brake pedal 26 is not depressed, the operating arm 26d of the left brake pedal 26 remains at the position shown in #2 of FIG. 6 (see FIGS. 3, 4, and 5).

[0078] When the contact pin 38b of the contact portion 38 contacts and is stopped by the operating arm 26d 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.

[0079] When the left brake pedal 26 is depressed, the operating arm 25d of the right brake pedal 25 that is not depressed remains at the position shown in #1 of FIG. 6 (see FIGS. 3, 4, and 5). When the contact pin 38b of the contact portion 38 contacts and is stopped by the operating arm 25d 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.

[0080] When the operator removes their foot from the stepping portions 25c and 26c of the brake pedals 25 and 26 in the state shown in #2 of FIG. 6, the brake pedals 25 and 26 are swing-operated (returned) backward (counterclockwise in FIG. 4) by the return springs 29. The operating arms 25d and 26d of the brake pedals 25 and 26 move forward and return to the position shown in #1 of FIG. 6 (see FIGS. 3, 4, and 5).

[0081] (Discrimination state of stepping operations of right and left brake pedals by brake sensor) - 2 When both the right and left brake pedals 25 and 26 are depressed as shown in #3 of FIG. 6 from the state shown in #1 of FIG. 6, the operating arms 25d and 26d of both the right and left brake pedals 25 and 26 move rearward.

[0082] As the operating arms 25d and 26d of both the right and left brake pedals 25 and 26 move rearward, the contact arm 38a of the contact portion 38 (the detection shaft 37a of the brake sensor 37) swings rearward (clockwise in FIG. 4) from the first position A1 while contacting the operating arms 25d and 26d of both the right and left brake pedals 25 and 26 so as to follow.

[0083] As shown in #4 of FIG. 6, when the contact arm 38a of the contact portion 38 (the detection shaft 37a of the brake sensor 37) reaches the second position A2, the contact arm 38a of the contact portion 38 (the detection shaft 37a of the brake sensor 37) hits the stopper portion 39 and is stopped, and cannot swing rearward (clockwise in FIG. 4) beyond the second position A2.

[0084] When both the right and left brake pedals 25 and 26 are further depressed, the operating arms 25d and 26d of both the right and left brake pedals 25 and 26 move rearward away from the contact pin 38b of the contact portion 38.

[0085] When the operator removes their feet from the stepping portions 25c and 26c of the brake pedals 25 and 26 from the state shown in #4 of FIG. 6, both the right and left brake pedals 25 and 26 are swung rearward (counterclockwise in FIG. 4) (returned) by the return springs 29.

[0086] Thereby, the operating arms 25d and 26d of both the right and left brake pedals 25 and 26 contact the contact pin 38b of the contact portion 38 at the second position A2 while moving forward, and while pushing the contact pin 38b of the contact portion 38 forward, return to the position shown in #1 of FIG. 6 (see FIGS. 3, 4, and 5).

[0087] 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 operation arms 25d, 26d of both the right and left brake pedals 25, 26.

[0088] (Correspondence with the 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 stepped on, the contact portion 38 contacts and stops at the contact portions (operation arms 25d, 26d) of the other of the right and left brake pedals 25, 26, so that the contact portion 38 does not follow the movement of the contact portion (operation arm 25d, 26d) of one of the right and left brake pedals 25, 26.

[0089] When both the right and left brake pedals 25, 26 are stepped on, the contact portion 38 moves following the movement of the contact portions (operation arms 25d, 26d) of both the right and left brake pedals 25, 26, and thus it is detected by the brake sensor 37 that both the right and left brake pedals 25, 26 have been stepped on.

[0090] (Operation based on the detection of the brake sensor)-1 As shown in FIGS. 2 and 6, the detection value of the brake sensor 37 due to the swing of the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) across 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.

[0091] In the above state, as shown from #1 in FIG. 6 to #2 in FIG. 6, when the right brake pedal 25 is depressed, the operation arm 26d of the non-depressed left brake pedal 26 remains at the position shown in #1 in FIG. 6. Since the contact pin 38b of the contact portion 38 contacts and is stopped by the operation arm 25d of the left brake pedal 25, the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) does not move from the first position A1.

[0092] When the left brake pedal 26 is depressed, the operation arm 25d of the non-depressed right brake pedal 25 remains at the position shown in #1 in FIG. 6. Since the contact pin 38b of the contact portion 38 contacts and is stopped by the operation arm 25d of the right brake pedal 25, the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) does not move from the first position A1.

[0093] As a result, since the brake sensor 37 does not detect a state in which both the right and left brake pedals 25 and 26 are depressed, 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.

[0094] (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.

[0095] In the above state, as shown from #1 in FIG. 6 to #3 and #4 in FIG. 6, assume that 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 axis 37a of the brake sensor 37) starts to move from the first position A1 toward the second position A2.

[0096] When the contact arm 38a of the contact portion 38 (the detection axis 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, 26 have been depressed. As a result, the continuously variable transmission 6 will start 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.

[0097] As both the right and left brake pedals 25, 26 are depressed and the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) approaches the second position A2, the continuously variable transmission 6 will be increasingly operated to the low speed side by the control device 21 and the transmission unit 19.

[0098] In this case, since there is mechanical play in the linkage mechanism 22 and the brakes 23, 24, during the above-mentioned period, even if the right and left brake pedals 25, 26 are depressed, the brakes 23, 24 are not actually braked yet.

[0099] Until the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) reaches the second position A2, when both the right and left brake pedals 25, 26 are depressed, the above-mentioned mechanical play will disappear, so the brakes 23, 24 will actually start to be braked.

[0100] 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 will stop. When both the right and left brake pedals 25, 26 are further depressed, the brakes 23, 24 will be braked and the aircraft 3 will stop.

[0101] (Operation based on detection of brake sensor) - 3 As described above, when 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, the continuously variable transmission 6 is operated to the shift position corresponding to the operation position of the shift lever 20.

[0102] When the contact arm 38a of the contact portion 38 (the detection axis 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.

[0103] When the contact arm 38a of the contact portion 38 (the detection axis 37a of the brake sensor 37) is in the range extending from the first position A1 to the second position A2, the operator can operate the continuously variable transmission 6 without braking the brakes 23 and 24 between the shift position corresponding to the operation position of the shift lever 20 and a shift position slightly lower than this shift position by stepping on and releasing both the right and left brake pedals 25 and 26.

[0104] (First alternative embodiment of the invention) In the right and left brake pedals 25 and 26, the operating arm 25d of the right brake pedal 25 may extend straight upward from the boss portion 25a, and the operating arm 26d of the left brake pedal 26 may be bent from the boss portion 26a toward the boss portion 25a of the right brake pedal 25 and extend upward, so that the operating arms 25d and 26d of the right and left brake pedals 25 and 26 are 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 26d of the left brake pedal 26.

[0105] (Second alternative embodiment of the invention) In the right and left brake pedals 25 and 26, the operating arm 26d of the left brake pedal 26 may extend straight upward from the boss portion 26a, and the operating arm 25d of the right brake pedal 25 may be bent from the boss portion 25a toward the boss portion 26a of the left brake pedal 26 and extend upward, so that the operating arms 25d and 26d of the right and left brake pedals 25 and 26 are 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 25d of the right brake pedal 25.

[0106] (Third Alternative Embodiment of the Invention) When the operating arms 25d and 26d of the brake pedals 25 and 26 are abolished, the brake sensor 37 and the contact portion 38 may be provided in front of the arm portions 25b and 26b of the right and left brake pedals 25 and 26.

[0107] According to the above configuration, the contact pins 38b of the contact portion 38 contact both of the 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 arm portions 25b and 26b of the brake pedals 25 and 26 move forward, the contact arm 38a (detection axis 37a of the brake sensor 37) of the contact portion 38 may be biased forward so as to follow the arm portions 25b and 26b of the brake pedals 25 and 26.

[0108] According to the above configuration, the brake sensor 37 and the contact portion 38 are provided at a position lower than the fulcrum shaft 27 (axis P1). The arm portions 25b and 26b of the brake pedals 25 and 26 serve as the contacted portions.

[0109] (Fourth Alternative Embodiment of the Invention) The operating arms 25d and 26d of the brake pedals 25 and 26 may be attached to the arm portions 25b and 26b and extend upward from the arm portions 25b and 26b beyond the fulcrum shaft 27 (axis P1).

[0110] (Fifth Alternative Embodiment of the Invention) The contact portion 38 may be provided swingably at a position different from the detection axis 37a of the brake sensor 37, rather than being attached to the detection axis 37a of the brake sensor 37. According to this configuration, another arm or the like (not shown) for transmitting the swing of the contact portion 38 to the detection axis 37a of the brake sensor 37 may be provided.

[0111] (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, rather than swing 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.

[0112] (Seventh alternative form of the invention) As control based on the detection of the brake sensor 37, control as described below may be performed.

[0113] 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 steps on the transmission pedal against the urging mechanism to operate the continuously variable transmission 6.

[0114] A holding mechanism is provided that can hold the transmission pedal at a desired operating position against the urging mechanism. The operator steps on the transmission pedal to a desired operating position and holds the transmission pedal by the holding mechanism, so that the machine body 3 can travel at a desired speed even when the foot is lifted from the transmission pedal.

[0115] In the above-described configuration, when the brake sensor 37 detects that both the right and left brake pedals 25, 26 have been stepped on, the holding mechanism is released. As a result, the transmission pedal returns to the neutral position N1 by the urging mechanism, the continuously variable transmission 6 is operated to the neutral position N1, and the load applied to the brakes 23, 24 is reduced.

Industrial applicability

[0116] 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 subsequent crawler travel device (corresponding to the travel device), and can also be applied to a work vehicle equipped with right and left crawler travel devices without front wheels 1 and rear wheels 2.

Explanation of reference numerals

[0117] 2 Rear wheels (traveling device) 23 Brake 24 Brake 25 Brake pedal 25b Arm part 25c Step part 25d Operating arm (contact part) 26 Brake pedal 26b Arm part 26c Step part 26d Operating arm (contact part) 37 Brake sensor 37a Detection shaft 38 Contact part 38a Contact arm 38b Contact pin 39 Stopper part 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, a right and left brake pedal having an arm portion swingably provided around a pedal axis along the left - right direction, extending downward from the pedal axis, a stepping portion attached to the lower portion of the arm portion, and a contact portion, and being 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 the stepping operation and the return operation of the brake pedal, and capable of contacting both of the contact portions of the right and left brake pedals, 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 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 of the right and left brake pedals are stepped on, the contact portion moves following the movement of both of the contact portions of the right and left brake pedals, and a work vehicle in which it is detected by the brake sensor that both of the right and left brake pedals have been stepped on.

2. the contact portion extends upward higher than the pedal axis, The work vehicle according to claim 1, wherein the brake sensor and the contact portion are provided at a position higher than the pedal axis.

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 the swing end of the contact arm and capable of contacting both of the contact portions of 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 both of the contact portions of 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 is capable of contacting the contact portions of both the right and left brake pedals.

6. The working vehicle according to claim 1, further comprising a stopper portion that stops the follow-up of the contact portion to the contacted portion at a predetermined position set in advance.

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