JP2015166635A5 - - Google Patents

Description

Work vehicle

  The present invention relates to a work vehicle.

  In a work vehicle such as a tractor, the rotation sensor that detects the rotation of the axle detects the rotation direction and the angular velocity of the axle, and controls the engagement of the starting clutch according to the detection result of the rotation sensor, thereby starting the hill. A technique for suppressing the backward movement of the vehicle at the time is known (for example, see Patent Document 1).

JP 2010-151160 A

  However, in the technique disclosed in Patent Document 1, since the rotation sensor detects the rotation of the axle, it takes time until the rotation sensor detects the rotation of the axle. Also, the detection was unstable due to the low rotational speed. For this reason, in the technique disclosed in Patent Document 1, it takes time until the rotation sensor detects the rotation of the axle, and the rotation of the axle cannot be accurately detected, and the vehicle restarts after stopping on the slope. At this time, if the brake pedal is released, the vehicle may move in an unintended direction such as retreating.

  This invention is made in view of the above, Comprising: It aims at providing the work vehicle which can suppress moving to the direction which the body, such as retreating, does not intend at the time of slope starting.

In order to solve the above-described problems and achieve the object, the work vehicle (1) according to claim 1 is transmitted from the airframe (2) on which the engine (7) is mounted and the engine (7). The left and right brake pedals (21 , 21 ) and the left and right brake pedals (21 , 21 ) for braking the wheel (5) driven by power according to the pedal operation are used. A connection pin (23) to be connected, a brake connection detection switch (24) for detecting whether the connection pin (23) has connected the left and right brake pedals (21 , 21 ) , and the brake pedal (21 , 21 ). Brake operation detecting means (25) for detecting pedal operation, forward / reverse hydraulic clutch for switching the forward / backward movement of the wheel (5) by the power and transmitting / disconnecting the power to the wheel (5) (124), a rotational speed / rotational direction detecting means (33) for detecting the rotational speed and rotational direction of the output shaft (142) output from the forward / reverse hydraulic clutch (124), and a clutch pedal (20) A no-clutch setting switch (28) for switching between execution and non-execution of a clutch control mode for stopping the airframe (2) without stopping the engine by only operating the brake pedal (21, 21) without pedal operation is provided. When the setting switch (28) switches the clutch control mode to the execution side, and the brake connection detection switch (24) detects the connection of the left and right brake pedals (21, 21), the clutch control mode can be executed, brake operation detecting means (25) detects a pedal operation of the brake pedal (21, 21), wherein When the rotation number / rotation direction detecting means (33) detects the rotation of the output shaft (142), the hydraulic pressure to the forward / reverse hydraulic clutch (124) is controlled so as to stop or substantially stop the machine body (2). And a control means (3).

The work vehicle (1) according to claim 2 is provided with a main speed change lever (29) on the right side of the cockpit (9) in the work vehicle (1), and the main speed change lever (29) with respect to the neutral position. Switching to manual shift when operated forward, switching to automatic shift when operating the main shift lever (29) backward with respect to the neutral position, switching the clutch control mode to the execution side when switching to automatic shift Further, the clutch control mode can be executed when the brake connection detection switch (24) detects the connection of the left and right brake pedals (21, 21) .

According to the first aspect of the invention, the brake operation detecting means (25) detects the pedal operation of the brake pedal (21), and the rotation speed / rotation direction detecting means (33) detects the rotation of the output shaft portion (142). When the airframe (2) is detected, the control means (3) controls the hydraulic pressure to the forward / reverse hydraulic clutch (124) so as to stop or substantially stop the airframe (2). For this reason, when the work vehicle (1) is operating the brake pedal (21) and the airframe (2) moves, that is, when the airframe (2) moves on a hill or the like, Since the rotation direction detection means (33) detects the rotation of the output shaft portion (142), the behavior of the airframe (2) can be detected sensitively (immediately), and the control means (3) immediately detects the airframe (2). Try to stop. Therefore, even if the work vehicle (1) is stopped on a slope or the like, even if the brake pedal (21) is released, the work vehicle (2) can be prevented from moving immediately, and the work vehicle (1) can move backward when the slope starts. It can suppress that an airframe (2) moves to the direction which is not intended.
Further, when the clutch control mode is executed by operating the nokura setting switch (28), the left and right brake pedals (21, 21) must be connected, so the left and right brake pedals (21, 21) are required when traveling on the road. ) Are operated simultaneously, so the aircraft can be stopped properly.

According to the second aspect of the invention, in addition to the effect of the first aspect, when the main transmission lever (29) is set to the automatic transmission, the clutch control mode is switched to the execution side, so that the operability is improved.

FIG. 1 is a side view showing a tractor as a work vehicle according to an embodiment. FIG. 2 is a block diagram of a tractor as a work vehicle according to the embodiment. FIG. 3 is a diagram showing a power transmission path of a tractor as a work vehicle according to the embodiment. Drawing 4 is a figure which looked ahead from the cockpit of the tractor as a work vehicle concerning an embodiment. FIG. 5 is a perspective view of a forward / reverse switching lever of a tractor as a work vehicle according to the embodiment. FIG. 6 is a diagram showing an operation range of the forward / reverse switching lever shown in FIG. FIG. 7 is a perspective view of a main transmission lever of a tractor as a work vehicle according to the embodiment. FIG. 8 is a diagram illustrating an operation range of the main transmission lever illustrated in FIG. 7. FIG. 9 is a diagram illustrating a brake pedal of a tractor as a work vehicle according to the embodiment. FIG. 10 is a diagram illustrating the relationship between the brake pedal of the tractor as the work vehicle according to the embodiment and the hydraulic pressure of the forward / reverse hydraulic clutch, and FIG. 10A is a diagram illustrating the operation position of the brake pedal and the like. (B) is a figure which shows the relationship between a brake operation position and the voltage output from a brake operation position sensor, (c) is a figure explaining the relationship etc. between a brake operation position and the hydraulic pressure of a forward / backward hydraulic clutch. It is. FIG. 11 is an example of a flowchart of the clutch control mode of the tractor as the work vehicle according to the embodiment of the present invention. FIG. 12 is an example of a time chart of the clutch control mode of the tractor as the work vehicle according to the embodiment of the present invention. FIG. 13 is a diagram for explaining an example of the relationship between the brake operation position when the tractor serving as the work vehicle according to the embodiment of the present invention starts on a slope and the hydraulic pressure of the forward / reverse hydraulic clutch. FIG. 14 is a diagram for explaining another example of the relationship between the brake operation position when the tractor as the work vehicle according to the embodiment of the present invention starts on a hill and the hydraulic pressure of the forward / reverse hydraulic clutch. FIG. 15 is a diagram for explaining still another example of the relationship between the brake operation position when the tractor as the work vehicle according to the embodiment of the present invention starts on a slope and the hydraulic pressure of the forward / backward hydraulic clutch.

Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the following embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or that are substantially the same, that is, those in an equivalent range. Moreover, the component in the following embodiment can be combined suitably.
[Embodiment]
A tractor 1 as a work vehicle according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing a tractor as a work vehicle according to an embodiment. FIG. 2 is a block diagram of a tractor as a work vehicle according to the embodiment. FIG. 3 is a diagram showing a power transmission path of a tractor as a work vehicle according to the embodiment. Drawing 4 is a figure which looked ahead from the cockpit of the tractor as a work vehicle concerning an embodiment.

  A tractor 1 as a work vehicle according to the embodiment is a work vehicle that performs work on a farm field or the like. As shown in FIG. 1, a front wheel 4 provided as a steering wheel and a rear wheel provided as a drive wheel. 5 and a traveling ECU 3 (corresponding to the control means shown in FIG. 2) and the like. The power generated in the engine 7 mounted in the hood 6 at the front of the fuselage 2 is appropriately decelerated by the main transmission 40 (shown in FIG. 3) and the auxiliary transmission 140 (shown in FIG. 3). The rear wheel 5 is driven by this power.

  Further, the tractor 1 can transmit the power generated by the engine 7 and decelerated by the main transmission 40 and the auxiliary transmission 140 to the front wheels 4 via the front wheel acceleration switching mechanism 172 (shown in FIG. 3). It has become. When the front wheel acceleration switching mechanism 172 transmits power, the tractor 1 is driven by the power transmitted from the engine 7 so that the front wheels 4 and the rear wheels 5 are driven, and the front wheel acceleration switching mechanism 172 transmits the power. When shut off, the two wheels including only the rear wheels 5 are driven by the power transmitted from the engine 7. That is, the tractor 1 can be switched between two-wheel drive and four-wheel drive. In addition, a PTO (Power Take-Off) connecting device 8 to which a work machine such as a rotary (not shown) can be mounted is disposed at the rear of the body 2 of the tractor 1.

  Further, as shown in FIG. 1, a pilot seat 9 is provided at the center of the fuselage 2 of the tractor 1, and a driver seat 9 is seated when the driver steers the tractor 1. As shown, a steering handle 10 used for steering the front wheels 4 is provided. The steering handle 10 is disposed on the upper end side of a handle post 11 that instructs the steering handle 10 to be rotatable. Further, as shown in FIG. 4, the clutch pedal 20 and the rear wheel 5 are placed on the lower side of the handle post 11, that is, in the vicinity of the driver's feet when the driver is sitting on the cockpit 9 according to the pedal operation. A brake pedal 21 and an accelerator pedal 22 for braking are installed.

  FIG. 9 is a diagram illustrating a brake pedal of a tractor as a work vehicle according to the embodiment. As shown in FIG. 9, the brake pedal 21 is provided with a brake pedal 21 for the left rear wheel 5 and a brake pedal 21 for the right rear wheel 5. These two brake pedals 21 are connected to each other by connecting a connecting pin 23 rotatably provided on one brake pedal 21 toward the other brake pedal 21 and engaging the other brake pedal 21. It is possible to make it. For this reason, when the two brake pedals 21 are operated independently, it is possible to generate a braking force independently for the left and right rear wheels 5, and the two brake pedals 21 are connected. When operated in a state, it is possible to generate a braking force for both the left and right rear wheels 5. In the vicinity of the two brake pedals 21, a brake connection detection switch 24 (shown in FIG. 2) for detecting whether or not the connection pin 23 connects the two brake pedals 21 is provided. The brake connection detection switch 24 outputs the detection result to the travel system ECU 3.

  A brake operation position sensor 25 (shown in FIG. 2 and corresponding to the brake operation detection means) for detecting the depression amount of the brake pedal 21 as a pedal operation of the brake pedal 21 by the operator is provided at the rotation center of the brake pedal 21. ing.

  In addition, the handle post 11 adjusts the engine speed, and an accelerator lever (not shown) that can maintain the engine speed at an arbitrary speed, and the traveling direction of the tractor 1 when moving forward and backward. And a forward / reverse switching lever 26 (shown in FIG. 5).

  FIG. 5 is a perspective view of a forward / reverse switching lever of a tractor as a work vehicle according to the embodiment. FIG. 6 is a diagram showing an operation range of the forward / reverse switching lever shown in FIG. The forward / reverse switching lever 26 is used to switch between forward and backward movement of the airframe 2 by power from the engine 7 by tilting forward when the tractor 1 is moved forward and tilting backward when the tractor 1 is moved backward. It is. Further, as shown in FIG. 6, the forward / reverse switching lever 26 has a neutral position between the forward position and the reverse position of the forward / reverse switching lever 26. In this neutral position, the tractor 1 moves forward. It is in a position that can prevent it from moving backward. In the forward / reverse switching lever 26, the operating position (forward, reverse, neutral) of the forward / reverse switching lever 26 is detected by a forward / backward lever operation position sensor 27 (corresponding to the forward / reverse switching lever detecting means shown in FIG. 2). That is, the forward / reverse lever operation position sensor 27 detects the operation position of the forward / reverse switching lever 26. The forward / reverse lever operation position sensor 27 outputs the detection result to the traveling system ECU 3.

  Further, a no-kura setting switch 28 (shown in FIGS. 2 and 5) is provided in the vicinity of the forward / reverse switching lever 26. The no-kura setting switch 28 is a switch that switches the running system ECU 3 between execution and non-execution of the clutch control mode in which the vehicle body 2 is stopped without being stalled only by operating the brake pedal 21 without operating the clutch pedal 20. The no-kura setting switch 28 is connected to the traveling system ECU 3 and executes the clutch control mode when turned on, and does not execute the clutch control mode when turned off.

  A main speed change lever 29 (shown in FIG. 7) for performing operations related to gear shifting during travel of the tractor 1 is disposed on the right side of the cockpit 9, and an auxiliary speed change lever (not shown) is provided on the left side of the cockpit 9. Is provided. FIG. 7 is a perspective view of a main transmission lever of a tractor as a work vehicle according to the embodiment. FIG. 8 is a diagram illustrating an operation range of the main transmission lever illustrated in FIG. 7.

  The main shift lever 29 can perform a main shift operation that is a shift of the main transmission 40, and can switch between an automatic shift that automatically performs the main shift and a manual shift that is arbitrarily performed by the driver. ing. The main transmission lever 29 switches the reduction ratio of the main transmission 40 to any one of the eight stages in manual transmission.

  Specifically, the main transmission lever 29 is configured to be movable in the front-rear direction, and as shown in FIGS. 7 and 8, the rear end side in the movement direction is an automatic transmission selection position, and the automatic transmission selection position is The forward position is a selection position of 1st to 8th gears to be switched during manual shifting. Further, a neutral position, which is a position where transmission of power generated by the engine 7 to the rear wheel 5 is interrupted, is selected between the selection position to be switched during manual shift and the selection position for automatic shift.

  The auxiliary transmission lever operates the auxiliary transmission device 140 and can switch the traveling speed between ultra-low speed, low speed, medium speed, high speed, and neutral. At an ultra-low speed, the sub-shift first shifter 144 is neutral, and the sub-shift second shifter 171 is connected to the front gear. At low speed, the sub-shift first shifter 144 is neutral and the sub-shift second shifter 171 is connected to the rear gear. At medium speed, the auxiliary transmission first shifter 144 is connected to the auxiliary transmission second gear 146, and the auxiliary transmission second shifter 171 is neutral. At high speed, the auxiliary transmission first shifter 144 is connected to the auxiliary transmission first gear 145, and the auxiliary transmission second shifter 171 is neutral.

  Further, as shown in FIG. 4, a meter panel 31 is disposed on the dashboard 30 located in front of the steering handle 10. The meter panel 31 is provided in the center of the dashboard 30 in the vehicle width direction, and can display various information necessary for driving the tractor 1, for example, an engine tachometer for displaying the engine speed, the vehicle speed and the current A data display unit for displaying the gear position, the remaining amount of fuel, and the like is arranged. The data display unit is a display unit using a liquid crystal panel, and can display arbitrary information by electronic control. Further, an operation panel 32 (shown in FIG. 2) for operating the lighting of a hazard lamp and the like is provided on the side of the meter panel 31.

  Further, the power of the engine 7 of the tractor 1 is transmitted to the rear wheel 5 via the main transmission 40, the forward / reverse hydraulic clutch 124, and the auxiliary transmission 140, as shown in FIG. The power of the engine 7 of the tractor 1 is also transmitted to the front wheels 4 via the main transmission 40, the forward / reverse hydraulic clutch 124, the auxiliary transmission 140, and the front wheel acceleration switching mechanism 172.

  As shown in FIG. 3, the main transmission 40 includes a Hi-Lo transmission mechanism 60 and a main transmission mechanism 90. The Hi-Lo transmission mechanism 60 further includes a first Hi-Lo transmission mechanism 61 and a second Hi transmission mechanism. The main transmission mechanism 90 includes a first main transmission mechanism 91 and a second main transmission mechanism 101.

  Among these, the first Hi-Lo speed change mechanism 61 includes a first Hi-Lo speed change Lo side gear 63 and a first Hi-Lo speed change Hi side gear 64 having different numbers of teeth. The gears 63 and 64 are connected to the main transmission input shaft first gear 43 fixed to the transmission input shaft 42 which is an input shaft when the power output from the engine 7 is input to the main transmission 40. It meshes with the transmission input shaft second gear 44. That is, the first Hi-Lo shift Lo side gear 63 is engaged with the main transmission input shaft first gear 43, and the first Hi-Lo shift Hi side gear 64 is engaged with the main transmission input shaft second gear 44.

  The first Hi-Lo speed change mechanism 61 includes a first Hi-Lo speed change clutch 62 and a first Hi-Lo speed change output gear 65. Further, the first Hi-Lo speed change clutch 62 is a first Hi-Lo speed change gear. A clutch that switches between the Lo-side gear 63 and the first Hi-Lo shift output gear 65; and a clutch that switches between the first Hi-Lo shift Hi-side gear 64 and the first Hi-Lo shift output gear 65. Yes. Therefore, the first Hi-Lo speed change clutch 62 is between the first Hi-Lo speed change Lo side gear 63 and the first Hi-Lo speed change Hi side gear 64 and the first Hi-Lo speed change output gear 65. Thus, it is possible to transmit power. Further, the first Hi-Lo speed change output gear 65 is fixed to a main speed change mechanism first intermediate shaft 81 capable of transmitting power between the first Hi-Lo speed change mechanism 61 and the first main speed change mechanism 91. The intermediate shaft gear 82 is engaged.

  Similarly, the second Hi-Lo speed change mechanism 71 has a second Hi-Lo speed change Lo side gear 73 and a second Hi-Lo speed change Hi side gear 74 having different number of teeth, and the second Hi-Lo speed change Lo side gear. 73 is meshed with the main transmission input shaft first gear 43, and the second Hi-Lo shift Hi side gear 74 is meshed with the main transmission input shaft second gear 44.

  The second Hi-Lo speed change mechanism 71 includes a second Hi-Lo speed change clutch 72 and a second Hi-Lo speed change output gear 75, and the second Hi-Lo speed change clutch 72 further includes a second Hi-Lo speed change gear 72. A clutch that switches between the Lo-side gear 73 and the second Hi-Lo shift output gear 75; and a clutch that switches between the second Hi-Lo shift Hi-side gear 74 and the second Hi-Lo shift output gear 75. Yes. For this reason, the second Hi-Lo shift clutch 72 is between the second Hi-Lo shift Lo side gear 73 and the second Hi-Lo shift Hi side gear 74 and the second Hi-Lo shift output gear 75. Thus, it is possible to transmit power. Further, the second Hi-Lo speed change output gear 75 is fixed to a main speed change mechanism second intermediate shaft 85 capable of transmitting power between the second Hi-Lo speed change mechanism 71 and the second main speed change mechanism 101. The intermediate shaft gear 86 meshes with the intermediate shaft gear 86.

  Here, the second Hi-Lo shift output gear 75 has a different number of teeth from the first Hi-Lo shift output gear 65, and the second intermediate shaft gear 86 also has a different number of teeth from the first intermediate shaft gear 82. ing. For this reason, the transmission ratio between the second Hi-Lo transmission output gear 75 and the second intermediate shaft gear 86 is different from the transmission ratio between the first Hi-Lo transmission output gear 65 and the first intermediate shaft gear 82. ing.

  The main transmission mechanism 90 has a main transmission mechanism output shaft first gear 111 and a main transmission mechanism output shaft second gear 112 fixed to a main transmission mechanism output shaft 110 that is an output shaft of the main transmission mechanism 90. The first main transmission mechanism 91 includes a first main transmission first gear 93 that meshes with the main transmission mechanism output shaft first gear 111 and a first main transmission second gear 94 that meshes with the main transmission mechanism output shaft second gear 112. And have.

  Further, the first main speed change mechanism 91 transmits the power transmitted from the main speed change mechanism first intermediate shaft 81 to one of the first main speed change first gear 93 and the first main speed change second gear 94. A first main transmission shifter 92 capable of transmission is provided. For this reason, the power transmitted from the main transmission mechanism first intermediate shaft 81 to the first main transmission 91 is transmitted through the first main transmission first gear 93 and the main transmission mechanism output shaft first gear 111, or The transmission can be transmitted to the main transmission mechanism output shaft 110 from any one of the transmission paths via the first main transmission second gear 94 and the main transmission mechanism output shaft second gear 112.

  Similarly, the second main transmission mechanism 101 includes a second main transmission first gear 103 that meshes with the main transmission mechanism output shaft first gear 111 and a second main transmission second gear that meshes with the main transmission mechanism output shaft second gear 112. 104 and a second main transmission shifter 102. For this reason, the power transmitted from the main transmission mechanism second intermediate shaft 85 to the second main transmission mechanism 101 is transmitted through the second main transmission first gear 103 and the main transmission mechanism output shaft first gear 111, or The transmission can be made to the main transmission mechanism output shaft 110 from any one of the transmission paths via the second main transmission second gear 104 and the main transmission mechanism output shaft second gear 112.

  Of the gears included in the main transmission mechanism 90, the first main transmission first gear 93 and the first main transmission second gear 94, the second main transmission first gear 103 and the second main transmission second gear 104, The transmission mechanism output shaft first gear 111 and the main transmission mechanism output shaft second gear 112 have different numbers of teeth. Therefore, the transmission ratio between the first main transmission first gear 93 and the main transmission mechanism output shaft first gear 111 and the first main transmission second gear 94 and the main transmission mechanism output shaft second gear 112 are between. This is different from the transmission ratio.

  As described above, the main transmission 40 that can transmit the power input from the engine 7 side to the output side by changing the gear ratio by the first Hi-Lo shift clutch 62 or the first main transmission shifter 92 is By changing the transmission path and changing the transmission gear ratio, an 8-speed gear stage is provided. In other words, the main transmission 40 switches the input from the main transmission input shaft first gear 43 or the main transmission input shaft second gear 44 (second speed), the first intermediate shaft gear 82, or the second intermediate shaft. The output from the gear 86 can be switched (second speed), and the output from the main transmission mechanism output shaft first gear 111 or the main transmission mechanism output shaft second gear 112 can be switched (second speed). For this reason, the main transmission 40 has a gear stage of 2nd speed × 2nd speed × 2nd speed = 8th speed. The eighth gear is assigned from the first gear to the eighth gear from the gear stage having a large reduction ratio from the main transmission input shaft 42 to the main transmission mechanism output shaft 110 toward the gear stage having a small reduction ratio. .

  A main transmission mechanism output shaft 110 that is an output shaft of the main transmission 40 is connected to a forward / reverse input shaft 121 that is an input shaft of a forward / reverse switching mechanism 120 including a forward / reverse hydraulic clutch 124. A forward / reverse input first gear 122 and a forward / reverse input second gear 123 are fixed to the forward / reverse input shaft 121, and among these, the forward / reverse input second gear 123 is provided by the forward / reverse switching mechanism 120. The counter gear 134 fixed to the counter shaft 133 is engaged with the counter gear 134.

  The forward / reverse switching mechanism 120 has a forward / reverse output first gear 131 that meshes with the forward / reverse input first gear 122 and a forward / reverse output second gear 132 that meshes with the counter gear 134. Further, the forward / reverse switching mechanism 120 uses the power transmitted to the forward / reverse output first gear 131 or the forward / reverse output second gear 132 as either the forward / reverse output first gear 131 or the forward / reverse output second gear 132. From one side, it has a forward / reverse hydraulic clutch 124 that can transmit to a forward / reverse output shaft 130 that is an output shaft of the forward / reverse switching mechanism 120.

  The forward / reverse hydraulic clutch 124 is used to switch between forward and reverse movement of the rear wheel 5 by the power transmitted from the engine 7, and to transmit and shut off the power transmitted from the engine 7 to the rear wheel 5. . The forward / reverse hydraulic clutch 124 includes a clutch that switches between the first and second output gears 131 and 130, and a clutch that switches between the second and second output gears 132 and 130. Thus, the gear connected to the forward / reverse output shaft 130 can be switched. The clutch on the forward / reverse output first gear 131 side and the clutch on the forward / rearward output second gear 132 side of the forward / reverse hydraulic clutch 124 operate by supplying hydraulic oil.

  Here, in the power transmission path from the forward / reverse input shaft 121 to the forward / reverse output shaft 130, the forward / reverse output first gear 131 directly meshes with the forward / reverse input first gear 122, whereas the forward / reverse output The second gear 132 meshes with the forward / reverse input second gear 123 via the counter gear 134. For this reason, in the forward / reverse output first gear 131 and the forward / reverse output second gear 132, the rotational directions are opposite. As a result, when the power transmission path to the forward / reverse output shaft 130 is switched by the forward / reverse hydraulic clutch 124, the forward / reverse output first gear 131 side and the forward / reverse output second gear 132 side are switched. In the case of switching, the rotational directions of the power transmitted to the forward / reverse output shaft 130 are opposite to each other.

  When the forward / reverse switching lever 26 is operated to the forward position, the forward / reverse hydraulic clutch 124 switches the power transmission path to the forward / reverse output shaft 130 to the forward / reverse output first gear 131 side, that is, the front side, and the rear wheel 5 is switched. Rotate in the forward direction. When the forward / reverse switching lever 26 is operated to the reverse position, the forward / reverse hydraulic clutch 124 switches to the forward / reverse output second gear 132 side, that is, the rear side, and rotates the rear wheel 5 in the reverse direction. The forward / reverse hydraulic clutch 124 blocks transmission of power transmitted from the engine 7 to the rear wheel 5 when both clutches interrupt transmission of power based on pedal operation of the clutch pedal 20 or the like. The rear wheel 5 is restricted from rotating by the power from the engine 7.

  In the clutch control mode, the forward / reverse hydraulic clutch 124 reduces the hydraulic pressure in both clutches in conjunction with the pedal operation of the brake pedal 21 without the clutch pedal 20 being operated. FIG. 10 is a diagram illustrating the relationship between the brake pedal of the tractor as the work vehicle according to the embodiment and the hydraulic pressure of the forward / reverse hydraulic clutch, and FIG. 10A is a diagram illustrating the operation position of the brake pedal and the like. FIG. 10 (b) is a diagram showing the relationship between the brake operation position and the voltage output from the brake operation position sensor, and FIG. 10 (c) shows the relationship between the brake operation position and the hydraulic pressure of the forward / reverse hydraulic clutch. It is a figure explaining a relationship.

  10B and 10C indicate the brake operation position and the operation direction, the right side is the open side, and the left side is the stepping side. The vertical axis in FIG. 10 (b) indicates the voltage output from the brake operation position sensor 25, and the vertical axis in FIG. 10 (c) indicates the forward / reverse output first gear 131 side of the forward / reverse hydraulic clutch 124, that is, the forward side. The clutch hydraulic pressure on the forward / reverse output second gear 131 side, that is, the reverse side is shown.

  The brake pedal 21 is operated by the pedal from the operation position A to the operation position B shown in FIGS. 10 (a) to 10 (c). A range between the operation position A and the operation position B is referred to as a brake pedal operation range. As shown in FIG. 10B, the brake operation position sensor 25 gradually decreases in the brake pedal operation range as the output voltage goes toward the stepping side. As shown in FIG. 10B, the brake operation position sensor 25 is a voltage for turning on the brake switch at the operation position C when the brake operation position sensor 25 is depressed from the open side toward the depression side in the brake pedal operation range. (Signal) is output. As shown in FIG. 10 (b), the brake operation position sensor 25 is a voltage for turning off the brake switch at the operation position D when the brake operation position sensor 25 is released from the depression side toward the release side in the brake pedal operation range. Signal). Further, in the brake pedal operation range, between the operation position A and the operation position D is a so-called play of the brake pedal 21.

  In the forward / reverse hydraulic clutch 124, in the clutch control mode, when the forward / reverse switching lever 26 is operated to the forward position, the hydraulic pressure of the front clutch changes as shown in FIG. When operated to the reverse position, the hydraulic pressure of the rear clutch changes as shown in FIG. In the clutch control mode, when the brake pedal 21 is not operated, the forward / reverse hydraulic clutch 124 transmits the power to the first forward / rearward output gear 131 or the second forward / reverse output gear 132 without loss as much as possible. The pressure P1 is maintained. Then, when the brake pedal 21 is depressed, the forward / reverse hydraulic clutch 124 has a predetermined pressure P2 that can stop the airframe 2 on a slope where the hydraulic pressure in the clutch is tilted by about 10 degrees. Reduced to The forward / reverse hydraulic clutch 124 maintains the hydraulic pressure in the clutch at the pressure P2 while the brake pedal 21 is operated.

  The forward / reverse hydraulic clutch 124 gradually increases the hydraulic pressure in the clutch from the pressure P2 as the brake pedal is released from the state where the brake pedal 21 in the brake pedal operation range is depressed most, so that the brake pedal 21 is moved to the operation position. When located at D, the pressure P3 is slightly higher than the pressure P2. In the forward / reverse hydraulic clutch 124, when the brake pedal 21 is released from the operation position D, the hydraulic pressure in the clutch gradually increases toward the pressure P1. Thus, as shown in FIG. 10 (c), the forward / reverse hydraulic clutch 124 is most depressed when the brake pedal 21 is operated from a state where the brake pedal 21 is not operated, and then released when the brake pedal 21 is released. The relationship between the hydraulic pressure and the operation position changes in the order of α, β, γ, δ, ε, α. In particular, the pattern for increasing the hydraulic pressure in the clutch from ε to α from the pressure P3 to the pressure P1 is predetermined and corresponds to a standard pattern described in the claims. The standard pattern is a pattern that can smoothly restart without traveling in an unintended direction when restarting from a slope inclined about 10 degrees.

  The forward / reverse output shaft 130 of the forward / reverse switching mechanism 120 is connected to a sub-transmission input shaft 141 that is an input shaft of the sub-transmission device 140, and the sub-transmission input shaft 141 has sub-transmission inputs having different numbers of teeth. The first gear 142 and the auxiliary transmission input second gear 143 are fixed.

  The sub-transmission device 140 includes a sub-transmission first gear 145 that meshes with the sub-transmission input first gear 142, and a sub-transmission second gear 146 that meshes with the sub-transmission input second gear 143. Further, the sub-transmission mechanism 140 transmits the power transmitted to the sub-transmission first gear 145 or the sub-transmission second gear 146 from either the sub-transmission first gear 145 or the sub-transmission second gear 146. A sub-shift first shifter 144 that can be transmitted to a sub-shift output shaft 150 that is an output shaft of the device 140 is provided. In addition, the sub-transmission mechanism 140 transmits any power transmitted to a gear having a different number of teeth between the front gear and the rear gear to any one of the gears having a different number of teeth between the front gear and the rear gear. On the other hand, a sub-transmission second shifter 171 that can be transmitted to the sub-transmission output shaft 150 that is the output shaft of the sub-transmission device 140 is provided.

  Here, the transmission ratio between the auxiliary transmission input first gear 142 and the auxiliary transmission first gear 145 and the transmission ratio between the auxiliary transmission input second gear 143 and the auxiliary transmission second gear 146 are different from each other. Yes. Therefore, when the transmission path of power to the auxiliary transmission output shaft 150 is switched between the auxiliary transmission first gear 145 side and the auxiliary transmission second gear 146 side by the auxiliary transmission first shifter 144, the auxiliary transmission input shaft The transmission gear ratio between 141 and the auxiliary transmission output shaft 150 changes. In addition, when the auxiliary transmission second shifter 171 is used to switch between the front gear and the rear gear, the transmission ratio between the auxiliary transmission input shaft 141 and the auxiliary transmission output shaft 150 changes. As described above, the sub-transmission device 140 has four-speed gear stages having different gear ratios and can be switched.

  An auxiliary transmission output gear 151 is fixed to the auxiliary transmission output shaft 150, and the auxiliary transmission output gear 151 is engaged with a rear wheel differential 155 that is a differential gear for the rear wheel 5. The rear wheel differential 155 is configured to be able to transmit power to the rear wheel drive shaft 156 connected to the rear wheel 5, whereby the power output from the auxiliary transmission 140 is transmitted to the rear wheel 5. Can be transmitted.

  Further, the auxiliary transmission device 140 is provided with a rotation sensor 33 (corresponding to the rotation number / rotation direction detecting means) for detecting the rotation number and the rotation direction of the auxiliary transmission input first gear 142. The rotation sensor 33 detects the rotation speed and rotation direction of the auxiliary transmission input first gear 142 as an output shaft portion output from the forward / reverse hydraulic clutch 124. In the present invention, the rotation sensor 33 may detect the rotation speed and the rotation direction using the auxiliary transmission input shaft 141 or the auxiliary transmission input second gear 143 as an output shaft portion. In short, in the present invention, as long as the rotation sensor 33 can detect the rotation speed and rotation direction of the output shaft portion output from the forward / reverse hydraulic clutch 124 before deceleration, the rotation sensor 33 can determine the rotation speed and rotation direction of any member regardless of the position. It may be detected.

  As shown in FIG. 3, the tractor 1 includes a PTO output mechanism 160 that transmits power generated by the engine 7 to the PTO shaft 8 a of the PTO coupling device 8. The PTO output mechanism 160 can receive power from the main transmission input shaft second gear 44 of the main transmission input shaft 42, and switches between transmission and interruption of power to the PTO shaft 8a side. It has a clutch 161 and a PTO transmission 162 that shifts when power is transmitted to the PTO shaft 8a.

  Further, as shown in FIG. 3, the tractor 1 includes a front wheel side power transmission mechanism 170 including a front wheel acceleration switching mechanism 172 that transmits power generated by the engine 7 to the front wheel 4 side. The front wheel side power transmission mechanism 170 is capable of receiving power from the auxiliary transmission device 140 and performs switching of the rotational speed when transmitting the power received from the auxiliary transmission device 140 to the front wheel 4 side. A front wheel acceleration switching mechanism 172 that switches between transmission and interruption of power to the front wheel 4 side is provided.

  The front wheel acceleration switching mechanism 172 is neutral when the two wheels are driven, that is, when the power to the front wheels 4 is cut off. The front wheel acceleration switching mechanism 172 connects the rear clutch when driving four wheels, that is, when transmitting power to the front wheel 4 side, and connects the front clutch when increasing the front wheel speed.

  A front wheel side power transmission gear 180 disposed on the output side of the front wheel side power transmission mechanism 170 meshes with a front wheel differential 181 that is a differential gear for the front wheel 4, and the front wheel differential 181 is coupled to the front wheel 4. Power is transmitted to the front wheel drive shaft 183 via a vertical shaft 182 and the like. As a result, the power output from the front wheel side power transmission mechanism 170 can be transmitted to the front wheel 4.

  As shown in FIG. 2, the traveling system ECU 3 includes an engine ECU 3 a that controls the engine 7, a work machine lifting system ECU 3 b that lifts and lowers a work machine mounted on the PTO coupling device 8, a meter panel 31, an operation panel 32, and the like. And CAN communication lines 1 and 2 (referred to as CAN1 and CAN2 in FIG. 2) so as to be able to communicate with each other alternately.

  The engine ECU 3 a receives the exhaust temperature from the engine exhaust temperature sensor 301, the engine speed from the engine rotation sensor 302, the engine lubricating oil pressure from the engine oil pressure sensor 303, and the engine water temperature sensor 304. The temperature of the cooling water is inputted, the pressure of the common rail (not shown) of the engine 7 is inputted from the rail pressure sensor 305, and the accelerator pedal 22 from the accelerator operation position detection sensor 306 that detects the pedal operation position of the accelerator pedal 22 is detected. The pedal operation position is entered. Further, the engine ECU 3a pressurizes fuel pumped from a fuel tank (not shown) and pumps it to the common rail, and a high-pressure injector 308 that injects high-pressure fuel accumulated in the common rail into the cylinder of the engine 7. A control signal for operating is output.

  The work implement elevating system ECU 3 b includes an operation signal of a position control sensor 310 provided on the work implement elevating lever, an elevating signal of a lift arm sensor 311, a raising position regulating signal of a raising position regulating dial 312, and a lowering speed adjusting dial 313. Each descent speed setting signal is input. The work implement elevating system ECU 3b outputs a work implement elevating signal to the main ascending solenoid 314 and the main descending solenoid 315 to operate a work implement elevating cylinder (not shown).

  The traveling system ECU 3 controls the traveling of the tractor 1 by controlling the main transmission 40, the auxiliary transmission 140, the forward / reverse switching mechanism 120, the PTO output mechanism 160, and the front wheel side power transmission mechanism 170. In the clutch control mode, the traveling system ECU 3 stops the machine body 2 when the brake operation position sensor 25 detects the pedal operation of the brake pedal 21 by the operator and the rotation sensor 33 detects the rotation of the auxiliary transmission input first gear 142. Alternatively, the hydraulic pressure to the front or rear clutch of the forward / reverse hydraulic clutch 124 is controlled so as to substantially stop.

  The traveling system ECU 3 includes a detection result from the brake connection detection switch 24, an engine speed from the engine rotation sensor 302, a traveling speed of the airframe 2 from the vehicle speed sensor 211, a detection result from the rotation sensor 33, and a temperature of the mission oil from the oil temperature sensor 320. The detection result of the brake operation position sensor 25 is input. In addition, the traveling system ECU 3 indicates the current switching state of the first main transmission mechanism 91, that is, the detection result of the first main transmission mechanism position sensor 215 that detects the state of the first main transmission shifter 92, as well as the current The detection result of the second main transmission mechanism position sensor 216 that detects the switching state of the second main transmission mechanism 101 is input.

  In the traveling system ECU 3, the detection result of the forward clutch pressure sensor 230 a that detects the hydraulic pressure of the clutch on the side of the forward / reverse output first gear 131 in the forward / reverse hydraulic clutch 124, and the forward / reverse output second gear 132 in the forward / reverse hydraulic clutch 124. The detection result of the reverse clutch pressure sensor 230b for detecting the hydraulic pressure of the side clutch is input.

  Further, the traveling system ECU 3 includes a detection result of the first clutch Lo side pressure switch 222 that detects the state of the first Hi-Lo shift Lo side gear 63 side clutch in the first Hi-Lo shift clutch 62, and the first Hi-Lo shift. The detection result of the first clutch Hi side pressure switch 221 for detecting the state of the clutch on the transmission Hi side gear 64 side is inputted. The traveling system ECU 3 includes a detection result of the second clutch Lo side pressure switch 226 that detects the state of the second Hi-Lo shift Lo side gear 73 side of the second Hi-Lo shift clutch 72, and a second Hi-Lo shift Hi. The detection result of the second clutch Hi side pressure switch 225 for detecting the state of the clutch on the side gear 74 side is input.

  The travel system ECU 3 detects information indicating ON / OFF from the nocturnal setting switch 28, detection result from the main transmission lever position sensor 210 that detects the operation position of the main transmission lever 29, and operation position of the sub transmission lever. The detection result from the sub-shift position sensor 231 to be detected, the detection result from the forward / reverse lever operation position sensor 27 for detecting the operation position of the forward / reverse switching lever 26, and the PTO rotation sensor 321 for detecting the rotational speed of the PTO shaft 8a. The detection result is input. Further, information indicating the state of a travel-work switch 322, a PTO automatic-manual switch 323, and a PTO on / off switch 324 provided on the operation panel 32 or the like is input to the travel system ECU 3.

  The traveling system ECU 3 includes a forward switching solenoid 261 that operates the clutch on the forward / reverse output first gear 131 side in the forward / backward hydraulic clutch 124, a reverse switching solenoid 262 that operates the clutch on the forward / reverse output second gear 132 side, In order to reduce the shock at the time of switching between reverse and reverse, a forward / reverse pressure boosting solenoid 265 for controlling the hydraulic pressure when the forward / reverse hydraulic clutch 124 is operated is connected to output these control signals.

  Further, the traveling system ECU 3 operates the first main transmission shifter 92 on the side where the main transmission mechanism first intermediate shaft 81 and the first main transmission first gear 93 are connected, A first main transmission second solenoid 252 that is operated on the side where the main transmission mechanism first intermediate shaft 81 and the first main transmission second gear 94 are connected is connected to output these control signals. The travel system ECU 3 operates the second main transmission shifter 102 on the side where the main transmission mechanism second intermediate shaft 85 and the second main transmission first gear 103 are connected to each other, and the main transmission first solenoid 255. A second main transmission second solenoid 256 that is operated to a side where the mechanism second intermediate shaft 85 and the second main transmission second gear 104 are connected is connected to output these control signals.

  Further, the traveling system ECU 3 engages the first Lo-side solenoid 242 that operates the clutch on the first Hi-Lo shift Lo side gear 63 side, and the clutch on the first Hi-Lo shift Hi side gear 64 side in the first Hi-Lo shift clutch 62. The first Hi solenoid 241 to be operated is connected to output these control signals. The travel system ECU 3 operates the second Lo-side solenoid 246 that operates the clutch on the second Hi-Lo shift Lo side gear 73 side, and the clutch on the second Hi-Lo shift Hi side gear 74 side in the second Hi-Lo shift clutch 72. The second Hi side solenoid 245 is connected to output these control signals.

  The traveling system ECU 3 includes a 4WD solenoid 325 and a front wheel acceleration solenoid 326 that operate the front wheel acceleration switching mechanism 172, a PTO clutch solenoid 327 that operates the PTO clutch 161, and a buzzer 328 that gives an alarm to the operator. Connected to output these control signals.

  When the traveling system ECU 3 controls the tractor 1, for example, based on the detection result of the main shift lever position sensor 210 and the like, the processing unit reads the computer program into a memory incorporated in the processing unit and calculates Then, the travel control of the tractor 1 is performed by controlling the actuators such as the first Hi-side solenoid 241 according to the calculation result. At that time, the processing unit appropriately stores a numerical value in the middle of the calculation in the storage unit, and retrieves the stored numerical value and executes the calculation.

  The tractor 1 according to the present embodiment is configured as described above, and the operation thereof will be described below. When the tractor 1 travels, the main transmission lever 29 and the auxiliary transmission lever are used to instruct a shift between the main transmission 40 and the auxiliary transmission 140, and the rotational speed of the engine 7 is adjusted using the accelerator pedal 22 or the accelerator lever. Further, when switching the traveling direction, the forward / reverse switching lever 26 is operated to switch between forward and reverse. These operations are detected by sensors and input to the traveling system ECU 3 and the like, and the traveling system ECU 3 operates a solenoid and the like based on the input information, thereby controlling the operation of the engine 7, the main transmission 40, and the auxiliary transmission. The shift control of the transmission 140 is performed and the vehicle travels in an arbitrary travel state.

  Further, the course is adjusted by operating the steering handle 10, and the deceleration is performed by operating the brake pedal 21. The brake pedal 21 is used not only when decelerating but also when turning sharply. That is, when making a sudden turn, only the front wheel 4 is steered by operating the brake pedal 21 corresponding to the inner rear wheel 5 in the turning direction to generate a braking force only on the rear wheel 5. It is possible to make a small turn rather than turning.

  In addition, the tractor 1 can perform work on the farm field or travel on the road. However, an appropriate speed region is different between the farm field and the road. For this reason, when the tractor 1 travels, the speed region is switched by operating the main shift lever 29 and the sub-shift lever according to the travel state such as the travel location. That is, by operating the main speed change lever 29 and the sub speed change lever, the speed region during traveling is switched.

  For example, when working in a field, the tractor 1 is configured so that the operator switches the main speed change lever 29 to any one of manual speed 1st to 8th speeds and the sub speed change lever according to the speed at the time of work. Is switched to ultra-low speed, low speed, medium speed, or high speed.

  The position of the main transmission lever 29 is detected by the main transmission lever position sensor 210, and the position of the auxiliary transmission lever is detected by the auxiliary transmission position sensor 231. In accordance with the detection result from the main shift lever position sensor 210, the travel system ECU 3 performs the first Hi side solenoid 241, the first Lo side solenoid 242, the second Hi side solenoid 245, the second Lo side solenoid 246, and the first main shift first solenoid. 251, the first main gear shift second solenoid 252, the second main gear shift first solenoid 255, and the second main gear shift second solenoid 256 are controlled so that the gear stage of the main transmission 40 is selected by the main gear shift lever 29. Switch to the selected gear. Further, the traveling system ECU 3 operates the auxiliary transmission first shifter 144 and the auxiliary transmission second shifter 171 in accordance with the detection result from the auxiliary transmission position sensor 231, and makes the auxiliary transmission device 140 operate at an extremely low speed, a low speed, and a medium speed. Switch to one of the high speeds.

  When traveling on the road, the tractor 1 is preferably configured so that the operator connects the two brake pedals 21 by the connecting pin 23 and switches the main transmission lever 29 to automatic transmission. When the main transmission lever 29 is switched to the automatic transmission, the tractor 1 performs an accelerator shift that is a shift control of the main transmission 40 based on the pedal operation of the accelerator pedal 22. This accelerator shift is performed according to the amount of depression of the accelerator pedal 22 detected by the accelerator operation position detection sensor 306, the vehicle speed detected by the vehicle speed sensor 211, and the engine speed detected by the engine rotation sensor 302. Change the gear position. That is, the gear position of the main transmission 40 corresponding to the amount of depression of the accelerator pedal 22, the vehicle speed, and the engine speed is preset and stored in the storage unit of the travel system ECU 3. The travel system ECU 3 The gear position corresponding to the detection result is derived, and the gear position of the main transmission 40 is switched to the derived gear position.

  Further, when traveling on the road, the tractor 1 turns on the nocler setting switch 28 in addition to the operator connecting the two brake pedals 21 by the connecting pin 23 and switching the main transmission lever 29 to automatic transmission. Therefore, it is desirable to execute the clutch control mode. By executing the clutch control mode, the tractor 1 can be stopped without operating the clutch pedal 20 and without stopping the engine 7 only by operating the brake pedal 21. FIG. 11 is an example of a flowchart of the clutch control mode of the tractor as the work vehicle according to the embodiment of the present invention. FIG. 12 is an example of a time chart of the clutch control mode of the tractor as the work vehicle according to the embodiment of the present invention.

  In the clutch control mode, the traveling system ECU 3 determines whether or not the brake connection detection switch 24 is on, and if it is not on (step ST1: No), repeats step ST1. That is, the traveling system ECU 3 restricts execution of the clutch control mode until the brake connection detection switch 24 is turned on, that is, until the two brake pedals 21 are connected. This is for restricting traveling on the road in a state where the two brake pedals 21 are not connected.

  Further, when the traveling system ECU 3 determines that the brake connection detection switch 24 is on (step ST1: Yes), the traveling system ECU 3 determines whether the no-kura setting switch 28 is turned on (step ST2). When the traveling system ECU 3 determines that the no-kura setting switch 28 is not turned on (step ST2: No), the traveling system ECU 3 determines whether or not the operation position of the main transmission lever 29 is automatic transmission (step ST3). When traveling system ECU 3 determines that the operation position of main transmission lever 29 is not automatic transmission (step ST3: No), it returns to step ST1. That is, the traveling system ECU 3 restricts execution of the clutch control mode unless the no-kura setting switch 28 is turned on, unless the operation position of the main transmission lever 29 is automatic transmission.

  When traveling system ECU 3 determines that the operation position of main shift lever 29 is an automatic shift (step ST3: Yes), even if no-kura setting switch 28 is not turned on, clutch control mode is turned on (step ST4). ). Then, the traveling system ECU 3 determines whether or not the brake operation position sensor 25 has detected the pedal operation of the brake pedal 21 (step ST5). The traveling system ECU 3 determines that the brake operation position sensor 25 has not detected the pedal operation of the brake pedal 21 (step ST5: No), and after the brake operation position sensor 25 has detected the pedal operation of the brake pedal 21 once. If it is determined that the detection is not stopped (step ST6: No), the process returns to step ST1. When the brake pedal 21 is not operated and the brake pedal 21 is not released after the pedal is operated, the traveling system ECU 3 does not stop, that is, the airframe 2 does not stop and restarts after stopping once. Otherwise, the process returns to step ST1, and steps ST1 to ST5 are repeated.

  When traveling system ECU 3 determines that brake operation position sensor 25 has detected the pedal operation of brake pedal 21 (step ST5: Yes), traveling system ECU 3 reduces the hydraulic pressure of forward / reverse hydraulic clutch 124 to pressure P2. The traveling system ECU 3 determines whether or not the rotation sensor 33 has detected the rotation of the auxiliary transmission input first gear 142, that is, whether or not the rear wheel 5 is rolling (step ST7). When the traveling system ECU 3 determines that the rotation sensor 33 has not detected the rotation of the auxiliary transmission input first gear 142, that is, determines that the rear wheel 5 is not rolling (step ST7: No), the traveling hydraulic clutch The hydraulic pressure of 124 is maintained at the pressure P2 (step ST8), and the process returns to step ST1. In this way, the traveling system ECU 3 detects that the brake operation position sensor 25 detects the pedal operation of the brake pedal 21 and the rotation sensor 33 does not detect the rotation of the sub-shift input first gear 142, the forward / reverse hydraulic clutch 124 is applied. The hydraulic pressure is maintained at pressure P2.

  The traveling system ECU 3 determines that the rotation sensor 33 has detected the rotation of the auxiliary transmission input first gear 142, that is, determines that the rear wheel 5 is rolling (step ST7: Yes), the rear wheel 5 is rolling. It is determined whether the current direction is the same direction as the operation position detected by the forward / reverse lever operation position sensor 27 (step ST9). When the traveling system ECU 3 determines that the direction in which the rear wheel 5 is rolling is the same as the operation position detected by the forward / reverse lever operation position sensor 27 (step ST9: Yes), the hydraulic pressure of the forward / reverse hydraulic clutch 124 is determined. The pressure P2 is reduced to the pressure P2 ″ (shown in FIG. 15) (step ST10), and the process returns to step ST1. In this way, the traveling system ECU 3 detects the pedal operation of the brake pedal 21 by the brake operation position sensor 25 and the sub-shift input in the same direction as the operation position of the forward / reverse switching lever 26 detected by the forward / reverse lever operation position sensor 27. When the rotation sensor 33 detects the rotation of the first gear 142, the pressure is reduced to a pressure P2 ″ lower than the hydraulic pressure P2 to the forward / reverse hydraulic clutch 124. In this case, the forward / reverse hydraulic clutch 124 is, for example, FIG. As shown in FIG. 4, when the brake pedal 21 is depressed most of the time when the pedal is not operated and then released, the relationship between the hydraulic pressure in the clutch and the operation position becomes α, β, γ. , Γ ″, δ ″, ε ″, α.

  When the traveling system ECU 3 determines that the rolling direction of the rear wheel 5 is opposite to the operation position detected by the forward / reverse lever operation position sensor 27 (step ST9: No), the hydraulic pressure of the forward / reverse hydraulic clutch 124 is determined. The pressure P2 is increased to the pressure P2 ′ (shown in FIG. 14) (step ST11), and the process returns to step ST1. Thus, the traveling system ECU 3 detects the pedal operation of the brake pedal 21 by the brake operation position sensor 25, and the sub-shift input in the direction opposite to the operation position of the forward / reverse switching lever 26 detected by the forward / reverse lever operation position sensor 27. When the rotation sensor 33 detects the rotation of the first gear 142, the hydraulic pressure to the forward / reverse hydraulic clutch 124 is increased to a pressure P2 ′ higher than the pressure P2. In this case, for example, as shown in FIG. 14, the forward / reverse hydraulic clutch 124 is depressed most of the time when the brake pedal 21 is operated from the state where the brake pedal 21 is not operated, and then released, the hydraulic pressure in the clutch is reduced. The relationship between the pressure and the operation position changes in the order of α, β, γ, γ ′, δ ′, ε ′, α.

  The traveling system ECU 3 determines that the brake operation position sensor 25 has not detected the pedal operation of the brake pedal 21 (step ST5: No), and after the brake operation position sensor 25 has detected the pedal operation of the brake pedal 21 once. When it is determined that it is no longer detected (step ST6: Yes), that is, in the case of re-start after stopping, whether or not the rotation sensor 33 has detected the rotation of the sub-shift input first gear 142, that is, It is determined whether or not the rear wheel 5 is rolling (step ST12).

  When the traveling system ECU 3 determines that the rotation sensor 33 has not detected the rotation of the auxiliary transmission input first gear 142, that is, determines that the rear wheel 5 is not rolling (step ST12: No), the forward / reverse hydraulic clutch The hydraulic pressure 124 is increased from the pressure P2 to the pressure P1 according to the standard pattern indicated by the solid line in FIG. 13 (step ST13), and the process returns to step ST1. Thus, when the brake operation position sensor 25 no longer detects the pedal operation of the brake pedal 21 from the state where the brake operation position sensor 25 detects the pedal operation of the brake pedal 21, the traveling system ECU 3 changes the hydraulic pressure to the forward / reverse hydraulic clutch 124 by the power. The pressure is increased from the pressure P2 to the pressure P1 so that the rear wheel 5 moves forward or backward. Further, when the rotation sensor 33 does not detect the rotation of the auxiliary transmission input first gear 142, the traveling system ECU 3 increases the hydraulic pressure to the forward / reverse hydraulic clutch 124 from the pressure P2 to the pressure P1 according to the standard pattern.

  The traveling system ECU 3 determines that the rotation sensor 33 has detected the rotation of the auxiliary transmission input first gear 142, that is, determines that the rear wheel 5 is rolling (step ST12: Yes), the rear wheel 5 is rolling. It is determined whether the current direction is the same direction as the operation position detected by the forward / reverse lever operation position sensor 27 (step ST14). When the traveling system ECU 3 determines that the direction in which the rear wheel 5 is rolling is the same as the operation position detected by the forward / reverse lever operation position sensor 27 (step ST14: Yes), the hydraulic pressure of the forward / reverse hydraulic clutch 124 is determined. The pressure is increased from the pressure P2 to the pressure P1 according to the standard pattern shown by the solid line in FIG. 13 (step ST15), and the process returns to step ST1. As described above, when the brake operation position sensor 25 no longer detects the pedal operation of the brake pedal 21 from the state in which the brake operation position sensor 25 detects the pedal operation of the brake pedal 21, the traveling ECU 3 detects the forward / reverse lever operation position sensor 27. When the rotation sensor 33 detects the rotation of the auxiliary transmission input first gear 142 in the same direction as the operation position of the forward / reverse switching lever 26, the hydraulic pressure to the forward / reverse hydraulic clutch 124 is increased from the pressure P2 to the pressure P1 according to the standard pattern.

  When the traveling system ECU 3 determines that the direction in which the rear wheel 5 is rolling is opposite to the operation position detected by the forward / reverse lever operation position sensor 27 (step ST14: No), the hydraulic pressure of the forward / reverse hydraulic clutch 124 is determined. The pressure P2 is increased to the pressure P1 according to a pattern that increases more rapidly than the standard pattern indicated by the dotted line in FIG. 13 (step ST16), and the process returns to step ST1. As described above, when the brake operation position sensor 25 no longer detects the pedal operation of the brake pedal 21 from the state in which the brake operation position sensor 25 detects the pedal operation of the brake pedal 21, the traveling ECU 3 detects the forward / reverse lever operation position sensor 27. When the rotation sensor 33 detects the rotation of the auxiliary transmission input first gear 142 in the direction opposite to the operation position of the forward / reverse switching lever 26, the hydraulic pressure to the forward / reverse hydraulic clutch 124 is higher than the standard pattern from the pressure P2 to the pressure P1. Increase with.

  Next, an example of the operation of the tractor 1 in the clutch control mode will be described with reference to FIG. In the clutch control mode, the operator connects the two brake pedals 21 with the connection pin 23 and outputs information indicating that the brake connection detection switch 24 is on to the traveling system ECU 3. When the operator turns on the nokura setting switch 28, information indicating that the nokura setting switch 28 is on is continuously output to the traveling system ECU 3. Then, as shown in FIG. 12, the operator operates the clutch pedal 20 to switch the auxiliary transmission lever, switch the main transmission lever 29 to automatic transmission, and switch the forward / reverse switching lever 26, for example, as shown in FIG. The forward / reverse lever operation position sensor 27 outputs information indicating that the operation position of the forward / reverse switching lever 26 is forward to the traveling system ECU 3.

  Then, the travel system ECU 3 operates the forward / reverse output first gear 131 side of the forward / reverse hydraulic clutch 124, that is, the front clutch by the forward switching solenoid 261, and the hydraulic pressure of the front clutch is set to the pressure P1 by the forward / reverse boost solenoid 265. Increase to. Then, the forward clutch pressure sensor 230a detects that the hydraulic pressure of the front clutch has increased to the pressure P1. In FIG. 12, the hydraulic pressure of the front clutch does not increase immediately after the forward / reverse switching lever 26 is switched to forward, but increases immediately after the pedal operation of the clutch pedal 20 is released. Then, the traveling system ECU 3 advances the body 2 at a speed corresponding to the pedal operation of the accelerator pedal 22 and the like.

  When the brake pedal 21 is operated by the pedal, the traveling system ECU 3 reduces the hydraulic pressure of the front clutch to the pressure P2 and stops the machine body 2. Thereafter, when the pedal operation of the brake pedal 21 is released, the hydraulic pressure of the front clutch is increased from the pressure P2 to the pressure P1 according to the standard pattern, and at a speed corresponding to the pedal operation of the accelerator pedal 22, etc. Move forward. When the brake pedal 21 is operated again, the traveling system ECU 3 reduces the hydraulic pressure of the front clutch to the pressure P2, stops the airframe 2, and then switches the forward / reverse switching lever 26 to neutral. The hydraulic pressure of the front clutch is reduced to zero pressure. Thereafter, the traveling system ECU 3 increases the hydraulic pressure of the rear clutch to the pressure P2 when the forward / reverse switching lever 26 switches to the reverse movement, and increases the hydraulic pressure of the rear clutch when the pedal operation of the brake pedal 21 is released. The pressure is increased to the pressure P1, and the body 2 is moved backward at a speed corresponding to the pedal operation of the accelerator pedal 22 or the like.

  As described above, according to the configuration of the tractor 1 of the present embodiment, the brake operation position sensor 25 detects the pedal operation of the brake pedal 21, and the rotation sensor 33 detects the rotation of the auxiliary transmission input first gear 142. When the vehicle body 2 moves, the traveling system ECU 3 controls the hydraulic pressure applied to the front clutch or the rear clutch of the forward / reverse hydraulic clutch 124 so that the vehicle body 2 is stopped or substantially stopped. For this reason, when the airframe 2 moves while the tractor 1 is operating the brake pedal 21, that is, when the airframe 2 moves on a hill or the like, the rotation sensor 33 is connected to the auxiliary transmission input first gear 142. Since the rotation is detected, the behavior of the airframe 2 can be detected sensitively (immediately), and the traveling system ECU 3 tries to stop the airframe 2 immediately. Therefore, even when the tractor 1 is stopped on a hill or the like and the pedal operation of the brake pedal 21 is released, the tractor 1 can suppress the movement of the airframe 2 immediately. It is possible to suppress movement against this.

  Further, when the tractor 1 does not detect the pedal operation from the state in which the brake operation position sensor 25 detects the pedal operation of the brake pedal 21, the traveling system ECU 3 supplies the hydraulic pressure to the front clutch or the rear clutch of the forward / reverse hydraulic clutch 124. Increase the pressure. Therefore, the tractor 1 can detect the release operation of the brake pedal 21 as an intention to start, and can adjust the hydraulic pressure of the forward / reverse hydraulic clutch 124. Therefore, the tractor 1 can start immediately after the release operation of the brake pedal 21, and can suppress the movement of the airframe 2 in an unintended direction such as backward movement when starting on a slope.

  Further, when the brake operation position sensor 25 detects the pedal operation of the brake pedal 21 and the rotation sensor 33 does not detect the rotation of the auxiliary transmission input first gear 142, that is, the vehicle body 2 is stopped. The ECU 3 maintains the hydraulic pressure applied to the front clutch or the rear clutch of the forward / reverse hydraulic clutch 124. Further, in the tractor 1, the auxiliary gear shift input first gear in the direction opposite to the operation position of the forward / reverse switching lever 26 detected by the forward / reverse lever operation position sensor 27 is detected by the brake operation position sensor 25 detected by the brake pedal 21. When the rotation sensor 33 detects the rotation of 142, the traveling system ECU 3 increases the hydraulic pressure to the front clutch or the rear clutch of the forward / reverse hydraulic clutch 124. For this reason, when the tractor 1 operates the brake pedal 21 and stops on the slope, the tractor 1 keeps the body 2 stopped if the body 2 is stopped. When attempting to move in a direction opposite to the operation position of the forward / reverse switching lever 26, the airframe 2 is to be stopped. Therefore, the tractor 1 can be prevented from moving in the direction opposite to the operation position of the forward / reverse switching lever 26 against the operator's intention.

  Further, in the tractor 1, the sub-shift input first gear in the same direction as the operation position of the forward / reverse switching lever 26 detected by the brake operation position sensor 25 when the brake operation position sensor 25 detects the pedal operation of the brake pedal 21. When the rotation sensor 33 detects the rotation 142, the traveling system ECU 3 reduces the hydraulic pressure applied to the front clutch or the rear clutch of the forward / reverse hydraulic clutch 124. Therefore, when the tractor 1 operates the brake pedal 21 and stops on the slope, if the tractor 1 tries to move on the slope in the same direction as the operation position of the forward / reverse switching lever 26, the body 2 Try to stop. Therefore, the tractor 1 can be prevented from moving in the same direction as the operation position of the forward / reverse switching lever 26 against the operator's intention.

  Further, when the rotation sensor 33 does not detect the rotation of the auxiliary transmission input first gear 142 when the brake operation position sensor 25 detects no pedal operation from the state where the brake operation position sensor 25 detects the pedal operation of the brake pedal 21, The hydraulic pressure to the front clutch or the rear clutch of the forward / reverse hydraulic clutch 124 is increased according to the standard pattern. For this reason, when the tractor 1 stops the pedal operation of the brake pedal 21 when starting on a flat road or starting on a hill, the hydraulic pressure to the forward / reverse hydraulic clutch 124 is increased according to the standard pattern, and the tractor 1 starts quickly. Can do.

  Further, when the brake operation position sensor 25 detects no pedal operation from the state where the brake operation position sensor 25 detects the pedal operation of the brake pedal 21, the rotation sensor 33 rotates in the direction opposite to the operation position of the forward / reverse switching lever 26. When detected, the hydraulic pressure to the front clutch or the rear clutch of the forward / reverse hydraulic clutch 124 is increased at a pressure higher than the standard pattern. For this reason, the tractor 1 can suppress the pedal operation of the brake pedal 21 when starting the hill, and can prevent the airframe 2 from moving in an unintended direction, and moves against the operator's intention when starting the hill. Can be suppressed.

  Further, when the brake operation position sensor 25 detects no pedal operation from the state where the brake operation position sensor 25 detects the pedal operation of the brake pedal 21, the rotation sensor 33 rotates in the same direction as the operation position of the forward / reverse switching lever 26. When detected, the hydraulic pressure to the front clutch or the rear clutch of the forward / reverse hydraulic clutch 124 is increased according to the standard pattern. For this reason, when the tractor 1 does not operate the brake pedal 21 when starting on a slope and tries to move in the same direction as the operation position of the forward / reverse switching lever 26, the hydraulic pressure to the forward / reverse hydraulic clutch 124 is changed to the standard pattern. The vehicle can be increased according to the speed and the vehicle can start immediately in the intended direction.

1 Tractor (work vehicle)
2 Airframe 3 Traveling ECU (control means)
5 Rear wheels
7 engine
9 cockpit
20 clutch pedal 21 brake pedal
23 connecting pins
24 brake connection detection switch 25 brake operation position sensor (brake operation detection means)
26 Forward / backward switching lever 27 Forward / backward lever operating position sensor (forward / backward switching lever detecting means)
28 Nokura setting switch
29 main speed change lever 33 rotation sensor (rotation speed / rotation direction detecting means)
124 Forward-reverse hydraulic clutch 142 Sub-transmission input first gear (output shaft)

Claims (2)

An airframe (2) carrying the engine (7);
Left and right brake pedals (21 , 21 ) for the left rear wheel and the right rear wheel for braking the wheel (5) driven by the power transmitted from the engine (7) according to the pedal operation;
A connecting pin (23) for connecting the left and right brake pedals (21, 21);
A brake connection detection switch (24) for detecting whether or not the connection pin (23) connects the left and right brake pedals (21, 21);
Brake operation detecting means (25) for detecting pedal operation of the brake pedal (21 , 21 );
A forward / reverse hydraulic clutch (124) for performing forward / backward switching of the wheel (5) by the power and transmission / disconnection of the power to the wheel (5);
Rotation speed / rotation direction detecting means (33) for detecting the rotation speed and rotation direction of the output shaft (142) output from the forward / reverse hydraulic clutch (124);
A nocler setting switch (28) for switching the clutch control mode for stopping or not executing the airframe (2) without stopping the engine only by operating the brake pedal (21, 21) without operating the clutch pedal (20). )
When the nocra setting switch (28) switches the clutch control mode to the execution side, and the brake connection detection switch (24) detects the connection of the left and right brake pedals (21, 21), the clutch control mode can be executed. ,
When the brake operation detecting means (25) detects the pedal operation of the brake pedal (21 , 21 ) and the rotation speed / rotation direction detecting means (33) detects the rotation of the output shaft portion (142), Control means (3) for controlling the hydraulic pressure to the forward / reverse hydraulic clutch (124) so as to stop or substantially stop the machine body (2);
A work vehicle (1) comprising: A main speed change lever (29) is provided on the right side of the cockpit (9), and when the main speed change lever (29) is operated forward with respect to the neutral position, it switches to manual speed change, and the main speed change lever (29) is moved to the neutral position. When the switch is operated backward, the automatic transmission is switched to the automatic shift. When the automatic shift is switched, the clutch control mode is switched to the execution side. The work vehicle (1) according to claim 1 , wherein the clutch control mode can be executed when connection is detected .