JP2014028584A - Tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of not becoming high mileage travel by just neglecting mode switching to high mileage, due to being difficult to understand switching timing to a high mileage mode and being complicated in a switching operation, since there are a plurality of control modes in engine control of a tractor, though conventional high mileage travel means switches mode selection means to the high mileage mode, when there is an allowance for travel driving force, when an operator feels an engine sound variation and a torque variation on a load state of an engine.SOLUTION: A tractor is provided with a high mileage switch 134, engine load detection means 109, and engine load display means 23, and switches an engine rotating speed to a specified rotating speed K of low rotation when turning on the high mileage switch 134 based on a low load state displayed on the engine load display means 23.

Description

  The present invention relates to a tractor that is an agricultural machine. In particular, the present invention relates to engine control of a tractor that can perform work with low fuel consumption.

Work vehicles such as construction machines can run and work in an energy-saving output mode in which the fuel consumption rate is lower than the normal consumption rate.
For example, Japanese Unexamined Patent Application Publication No. 2007-231848 describes a construction machine engine control method in which engine control is switched to a low fuel consumption mode specification, that is, an energy saving output mode by mode selection means. Yes.

JP 2007-231848 A

  Conventional low fuel consumption travel means switch the mode selection means to the low fuel consumption mode when the operator feels engine load changes and torque fluctuations in the engine load state and there is a margin in travel drive force. There are multiple control modes for tractor engine control, the timing of switching to the low fuel consumption mode is difficult to understand, the switching operation is complicated, and the mode switching to low fuel consumption is neglected so that low fuel consumption driving does not occur There is.

The problems of the present invention are solved by the following technical means.
The invention according to claim 1 is provided with a low fuel consumption switch 134, an engine load detecting means 109 and an engine load display means 23, and the low fuel consumption switch 134 is turned on based on the low load state displayed on the engine load display means 23. In this case, the tractor is characterized in that the engine speed is switched to a specified speed K which is low.

The invention described in claim 2 is the tractor according to claim 1, wherein the specified rotational speed K is the engine rotational speed during turning control.
The invention according to claim 3 is the tractor according to claim 1, wherein the specified engine speed K is the engine speed at the time of reverse travel.

  According to the fourth aspect of the present invention, when the low fuel consumption switch (134) is turned on, the engine speed is switched to a predetermined specified speed (K) and the gear stage of the gear transmission (59) is set to the high gear stage side. The tractor according to claim 1, wherein the tractor is switched.

  According to the first aspect of the present invention, the operator of the tractor can see the low load state displayed on the engine load display means 23, so that even if the engine speed is switched to the specified low speed K, the engine speed can be reduced. When the low fuel consumption switch 134 is turned on, the engine speed can be switched to the specified rotational speed K and the low fuel consumption traveling can be easily performed.

  According to the second aspect of the present invention, by setting the engine speed of the specified speed K set by the low fuel consumption switch 134 as the engine speed at the time of turning control, a new control speed is not newly set. Can be easily set using the engine rotation control of the tractor.

  According to the invention of claim 3, by setting the engine speed of the specified speed K set by the fuel-efficient switch 134 as the engine speed at the time of reverse travel, without newly setting another control speed, It can be easily set using the engine rotation control of the tractor.

  According to the fourth aspect of the present invention, even if the engine speed is reduced to the specified speed K by turning on the low fuel consumption switch 134, the gear speed of the gear transmission is switched to the high speed side to thereby increase the travel speed. Can be maintained at substantially the same traveling speed.

Schematic diagram of common rail engine control configuration Comparison chart of engine speed control mode Engine output characteristics Overall side view of tractor Power transmission diagram in the mission case Control block diagram Enlarged view of the meter panel Enlarged view of the data display An enlarged perspective view of a part around the right side of the steering handle Front side view of the entire front loader

  The best mode for carrying out the present invention will be described below with reference to embodiments shown in the drawings. In this specification, the left and right directions in the forward direction of the tractor are referred to as left and right, respectively, the forward direction is referred to as forward, and the reverse direction is referred to as rear.

FIG. 1 is a schematic diagram of a control configuration of a common rail engine using an accumulator fuel injection device.
The accumulator fuel injection device is applied to, for example, a multi-cylinder diesel engine, but may be a gasoline engine. The accumulator fuel injection device pressurizes the common rail 1 that accumulates fuel at an injection pressure that appropriately controls the fuel, the rail pressure sensor 2 that is attached to the common rail 1, and the fuel pumped up from the fuel tank 3 to the common rail 1. A high-pressure fuel pump 4 for pumping, a high-pressure injector 6 for injecting high-pressure fuel accumulated in the common rail 1 into the cylinder 5 of the engine E, an engine control device for controlling the fuel high-pressure pump 4, the high-pressure injector 6 and other operations. (Engine ECU) 12 and the like, and the fuel injected into each cylinder 5 of the engine E is set to a pressure necessary for the requested output.

  The fuel in the fuel tank 3 is sucked into the fuel high-pressure pump 4 driven by the engine E through the fuel filter 7 through the suction passage, and the high-pressure fuel pressurized by the fuel high-pressure pump 4 passes through the discharge passage 8 to the common rail 1. To be stored.

  The high-pressure fuel in the common rail 1 is supplied to the high-pressure injectors 6 corresponding to the number of cylinders through the high-pressure fuel supply passages 9, and the high-pressure injectors 6 are operated based on commands from the engine ECU 12. The surplus fuel (return fuel) in each high-pressure injector 6 is injected into the room and guided to the common return passage 10a by each return passage 10 and is returned to the fuel tank 3 by this return passage 10a.

  Further, in order to control the fuel pressure (common rail pressure) in the common rail 1, a pressure control valve 11 is provided in the fuel high-pressure pump 4, and this pressure control valve 11 is supplied from the fuel high-pressure pump 4 by the signal from the engine ECU 12. The flow path area of the return passage 10a for surplus fuel to the tank 3 is adjusted, whereby the fuel supply amount to the common rail 1 side can be adjusted to control the common rail pressure.

  Specifically, the target common rail pressure is set according to the operating condition of the engine E, and the common rail pressure is fed back via the pressure control valve 11 so that the common rail pressure detected by the rail pressure sensor 2 matches the target common rail pressure. It is configured to control.

  As shown in FIG. 2, the engine ECU 12 of the diesel engine E having the common rail 1 in a farm machine such as a tractor has an engine speed fluctuation control mode A, an engine speed maintenance control mode B, and a heavy load in relation to the speed and output torque. The load mode C has three types of control modes.

  In the engine speed fluctuation control mode A, the output fluctuates due to the fluctuation of the engine speed. Basically, it is used for traveling, but it is also used during work to prevent sudden engine stalls. For example, in the case of mobile travel, if the travel speed is reduced or stopped by applying a brake, the engine speed decreases as the travel load increases, so the travel speed can be safely reduced or stopped. Is. Further, during the work, when the work load is applied, the engine speed decreases according to the load.

  The engine speed maintaining control mode B is control for maintaining the engine speed constant even when the load increases. Basically, it is used when working. For example, the tractor is when the field is hard during the plowing operation and resistance is applied to the plowing blade, and the combine is when the rotation speed is maintained even when the load is increased during the harvesting operation.

  In the heavy load mode C, in addition to the control for maintaining the engine speed constant even when the load fluctuates, as in the engine speed maintenance control mode B, the heavy load mode C increases the engine speed to increase the output when the load is close to the load limit. This is a control with added control. In particular, it is used when working near the load limit. For example, when plowing work with a tractor, the engine output increases beyond the normal limit even when encountering hard cultivated land, so work can be performed efficiently without interruption. .

FIG. 3 is a relationship diagram between the rotational speed and the output representing the output characteristics of the engine E in the normal work mode B.
The engine output horsepower curve S and the torque output curve N change according to the engine speed, and the torque output curve N becomes maximum at a substantially middle position (1800 rpm) in the entire rotation range, and the output horsepower curve S is close to the maximum speed ( 2600 rpm) and then rapidly decreases.

  When the fuel efficiency switch 134 is turned on with 2000 rpm which is slightly higher than the maximum torque generation rotation speed (1800 rpm) as the specified rotation speed K, the injection amount of the high pressure injector 6 is adjusted so that the engine rotation speed decreases to the specified rotation speed K. ing. The low fuel consumption switch 134 is shown in FIGS.

  When the tractor starts traveling, the mode is automatically switched to the engine speed fluctuation control mode A. When the PTO drive switch 151 that drives the work machine mounted on the tractor is turned on, the engine speed is automatically switched to the engine speed maintenance control mode B. The PTO drive switch 151 may be turned on by operating the PTO lever.

By switching off the PTO drive switch 151, the engine speed fluctuation control mode A is automatically switched.
As described above, during the operation with the PTO drive switch 151 turned on, the engine speed control is automatically performed in the engine speed maintenance control mode B. When the PTO drive switch 151 is turned on, the PTO clutch sol (solenoid) 54b shown in FIG. 6 described later is energized, and the PTO clutch 54a shown in FIG. 5 is turned on.

Then, when the drive torque monitor lamp 23 of the meter panel 117 is displayed in green indicating that the engine load is sufficient, the engine speed is decreased from 2650 rpm to 2000 rpm, for example, when the operator turns on the fuel-efficient switch 134. (A → B in Fig. 3)
Further, the shift speed of the double sub-shift clutch 59 is automatically shifted to the high shift speed side to prevent the travel speed from being lowered due to the decrease in the engine speed so that the travel speed is the same as the previous travel speed. . In this case, even when the running load is on the engine output curve N and the engine speed is reduced, if the engine speed is up to the specified speed K after a predetermined elapsed time, that fact is displayed on the engine load display and the high shift stage side is displayed. Persist shift state.

  If the running load still has a certain margin after the predetermined elapsed time even if the gear position of the double sub-transmission clutch 59 is shifted one step to the high gear side, that fact is displayed on the engine load display. You may make it shift to a high gear stage.

  Also, if the engine speed falls below the specified speed K after a predetermined elapsed time due to the shift to the high gear position side, a red overload warning is displayed on the drive torque monitor lamp 23, and the engine speed is restored. And the gear position of the double sub-transmission clutch 59 is automatically shifted to the lower gear position side to prevent the traveling speed from increasing due to the increase in the engine speed. To be.

  As another configuration, the load factor of the PTO output shaft 54c (FIG. 5) that drives the work machine is detected, and the vehicle is working or running at about 70% or less of the maximum output of the standard engine output curve N for a certain period of time. In this case, the engine speed is automatically reduced to the specified speed K. This makes it possible to perform efficient and fuel-efficient work and travel. The load factor of the PTO output shaft 54c is calculated from the current rotational speed with respect to the specified rotational speed.

  Conversely, when the vehicle runs at a specified rotational speed for a certain period of time and is working or running at about 70% or more of the maximum output of the engine output curve S, it is automatically switched to the standard engine rotational speed. To do. In this way, it is possible to work and travel by drawing out the capabilities of the engine itself.

Note that the speed change of the double sub-transmission clutch 59 may be performed by the first speed / third speed switching first speed change clutch 34 and the second speed / four speed speed changing second speed change clutch 35.
In the engine speed fluctuation control mode A, the engine speed maintenance control mode B, and the heavy load mode C, a shift operation of a traveling speed change lever of a farm vehicle (tractor, combine, rice transplanter, etc.) or a work clutch (whether it is a tractor) It may be configured to automatically switch to the engine speed maintenance control mode B by an on / off operation or the like of a PTO clutch for rotary drive or the like, and for a combine, a drive clutch for a reaping part or a threshing part. In the tractor, even if the PTO clutch is disengaged, if the lift arm connecting the work machine is lower than the uppermost position and the lift arm is raised and lowered, it is plow work or plastic work, The engine speed maintaining control mode B and heavy load mode C are automatically set.

  Further, the engine speed fluctuation control mode A, the engine speed maintenance control mode B, and the heavy load mode C may be manually switched by operating the engine speed control mode changeover switch 148 (FIG. 6). Good. In the case of manual operation, the driver selects it.

  Further, when the low fuel consumption switch 134 is in the on state, the engine speed fluctuation control mode A may be always set. The engine speed fluctuation control mode A may also be used when the low fuel consumption switch 134 is off and the shift is automatically performed by operating the accelerator pedal.

FIG. 4 shows a tractor 15 as a work vehicle in which the present invention is implemented.
The tractor 15 has an engine E mounted in a bonnet at the front part of the machine body, transmits the rotational power of the engine E to the transmission in the transmission case 16, and the rotational power decelerated by the transmission is transmitted to the front wheels 17 and the rear wheels 18. To tell. The area around the cockpit 22 on the aircraft is covered with a cabin 19. A steering handle 20 is erected from a dashboard 13 provided with a meter panel 117 on the front side of the cockpit 22 inside the cabin 19, and a forward / reverse lever, a parking brake lever, a PTO shift lever, and the like are disposed around the steering handle 20. The engine E is the common rail type diesel engine.

A hitch 21 and a three-point link (not shown) are provided between the left and right rear wheels 18 and 18 so that a working machine such as a rotary is mounted.
FIG. 7 is an enlarged view of the meter panel 117. FIG. 8 is an enlarged view of the liquid crystal data display unit 14 in the meter panel 117 and shows an example of display. FIG. 9 is an enlarged perspective view around the right side of the steering handle 20 erected on the dashboard 13.

  The meter panel 117 on the front side of the steering handle 20 has an engine tachometer 24 disposed at the center, a liquid crystal data display unit 14 disposed on the right side, and a drive torque monitor lamp 23 disposed on the left side.

  The data display unit 14 includes a shift speed display 14a for displaying the current shift speed, a fuel consumption rate display 14b, and the like, and the fuel consumption rate display 14b is switched to the traveling speed display 14c at regular intervals. The fuel consumption rate is the ratio of the fuel injection amount that is actually injected to the fuel injection amount for producing the maximum output at the engine speed at that time. The data display unit 14 is also configured to display a fuel gauge 14d and an engine coolant temperature gauge 14e.

The drive torque monitor lamp 23 lights in red when the drive torque is 70% or less of the maximum torque and there is remaining drive power, and lights in green when the drive torque is 70% or more of the maximum torque.
Further, as shown in FIG. 9, a low fuel consumption switch 134 is provided on the dashboard 13 on the right side of the steering handle 20. When the low fuel consumption switch 134 is pressed, the mechanical governor is rotated and adjusted by the governor motor 153, and the engine speed becomes the specified speed. The specified rotational speed is set to a slightly higher rotational speed side than the maximum torque generating rotational speed, but the control rotational speed can be reduced by setting the engine rotational speed during turning and the engine rotational speed during reverse travel set during turning.

FIG. 5 is a diagram showing a transmission mechanism of the transmission in the transmission case 16. A power transmission configuration from the engine E to the front wheels 17 and the rear wheels 18 will be described.
A first gear 26 is fixed to the input shaft 25 directly connected to the output shaft of the engine E, and a forward / reverse switching clutch 27 is mounted.

  One second gear 28 of the forward / reverse switching clutch 27 meshes with a third gear 30 fixed to the first transmission shaft 29 and decelerates, and the other fourth gear 31 of the forward / reverse switching clutch 27 moves the counter gear 32. Through the fifth gear 33 fixed to the first transmission shaft 29, and the power is transmitted in the reverse direction. That is, when the forward / reverse switching clutch 27 is placed (connected) on the second gear 28 side, the rotation of the input shaft 25 is transmitted in the reverse direction to the first transmission shaft 29, and when it is placed on the fourth gear 31 side, The neutral state in which the rotation of 25 is transmitted to the first transmission shaft 29 in the forward direction and is separated from both the second gear 28 and the fourth gear 31 is the main clutch disengaged state in which the power transmission is cut off. The main clutch disengaged state can be maintained by controlling the hydraulic valve. That is, the forward / reverse switching clutch 27 that operates during automatic control, when operating the forward / reverse lever, and when operating the clutch pedal functions as a main clutch.

On the first transmission shaft 29 on the lower transmission side of the forward / reverse switching clutch 27, a first transmission clutch 34 for switching to the first / third speed and a second transmission clutch 35 for switching to the second / fourth speed are mounted. ing.
The first clutch gear 36 and the second clutch gear 37 of the first transmission clutch 34 for switching between the first speed and the third speed mesh with the third clutch gear 39 and the fourth clutch gear 40 fixed to the second countershaft 38, The rotation of the first transmission shaft 29 is transmitted to the second counter shaft 38 for the first speed or the third speed.

  Further, the fifth clutch gear 41 and the sixth clutch gear 42 of the second speed / second speed switching second transmission clutch 35 are engaged with the seventh clutch gear 43 and the eighth clutch gear 44 fixed to the second counter shaft 38. Thus, the rotation of the first transmission shaft 29 is transmitted to the second counter shaft 38 for the second speed or the fourth speed.

  The third counter shaft 45 is connected to the lower transmission side of the second counter shaft 38 by a coupling 46, and the rotation is transmitted as it is. A small gear 47 and a large gear 48 are fixed to the third counter shaft 45. The small gear 47 and the large gear 48 mesh with the large clutch gear 51 and the small clutch gear 52 of the high / low speed switching clutch 50 mounted on the second transmission shaft 49, respectively, and the third counter shaft 45 rotates at high speed or low speed. The power is transmitted to the second transmission shaft 49 at a low speed.

  A sixth gear 53 is fixed to the lower transmission side end portion of the second transmission shaft 49, and the sixth gear 53 is a large gear 56 of a large and small gear 55 portion rotatably supported on the third drive shaft 54. And is decelerating.

  The small gear 57 of the large and small gears 55 meshes with the seventh gear 60 of the double auxiliary transmission clutch 59 that is pivotally supported by the bevel gear shaft 58 and is transmitted at a reduced speed. Further, an eighth gear 61 provided integrally with the seventh gear 60 is engaged with a second large gear 63 fixed to the fifth counter shaft 62 for transmission at a reduced speed.

  A second small gear 64 is further fixed to the fifth counter shaft 62, and the second small gear 64 meshes with the third large gear 65 of the bevel gear shaft 58 to further reduce the transmission. Accordingly, the rotation of the second transmission shaft 49 is as follows: sixth gear 53 → large gear 56 → small gear 57 → seventh gear 60 → eighth gear 61 → second large gear 63 → second small gear 64 → third large gear. It is transmitted while being decelerated sequentially with 65.

  The first shifter 66 and the second shifter 67 of the double auxiliary transmission clutch 59 operated by the auxiliary transmission lever are slidably engaged with the bevel gear shaft 58 in the axial direction, and the first shifter 66 is engaged with the seventh gear. When slid to 60 side and engaged, the rotation of the seventh gear 60 is transmitted to the bevel gear shaft 58, and when the second shifter 67 is slid and engaged to the eighth gear 61 side, the rotation of the eighth gear 61 is rotated to the bevel gear shaft. As a result, the bevel gear shaft 58 is rotated at a low speed.

  The rotation of the bevel gear shaft 58 is transmitted to the differential gear 70 through the first bevel gear 68 and the second bevel gear 69, and is transmitted from the differential gear 70 to the rear wheel 18 through the axle 71 and the planetary gear 72.

  In summary, the rotation of the input shaft 25 is first switched to forward rotation or reverse rotation by the forward / reverse switching clutch 27, and the first transmission clutch 34 for the first speed / three speed switching and the second speed / fourth speed switching first clutch 34. The speed is changed in four stages from first to fourth speed by the two-speed clutch 35, the speed is changed to two speeds of high speed and low speed by the high / low speed switching clutch 50, and further, high, medium and low speed 3 are selected by two sub-shift clutches 59 The gear is shifted in stages and transmitted to the bevel gear shaft 58. That is, the rotation of the input shaft 25 is shifted to 4 × 2 × 3 = 24 speeds and transmitted to the axle 71.

  For driving force transmission to the front wheel 17, the ninth gear 74 is fixed to the bevel gear shaft 58, the ninth gear 74 is meshed with the relay gear 75, and further meshed with the tenth gear 77 fixed to the third drive shaft 76. Then, the third drive shaft 76 is driven. The third drive shaft 76 is connected by a second coupling 78 to a transmission shaft 80 on which a front wheel speed increasing clutch 79 is mounted. The eleventh gear 81 and the twelfth gear 82 of the front wheel speed increasing clutch 79 are engaged with the thirteenth gear 84 and the fourteenth gear 85 fixed to the seventh countershaft 83, so that the front wheel drive is changed from the normal front wheel drive to the front wheel. The speed is switched to speedup. When the front wheel acceleration clutch 79 is neutral, the front wheel 17 is not driven and only the rear wheel is driven.

  The seventh counter shaft 83 is connected to the front wheel drive shaft 87 by a third coupling 86, and is further connected to the front wheel drive bevel shaft 91 by a fourth coupling 88, an extension shaft 89 and a fifth coupling 90.

  The power of the front wheel drive bevel shaft 91 is as follows: front first bevel gear 92, front second bevel gear 93, front differential gear 94, front differential gear shaft 95, front third bevel gear 96, front fourth bevel gear 97, vertical shaft 98, front fifth bevel gear. 99, the front wheel 17 is driven through the front sixth bevel gear 100 and the front planetary gear 101.

  A PTO output shaft 54 c is connected to the lower transmission side of the third drive shaft 54. The PTO output shaft 54c is configured to be driven via a PTO transmission 54d, a PTO counter shaft 54e, and a third drive shaft 54.

Next, the flow of the control signal will be described with reference to the control block diagram of FIG.
First, the engine ECU (engine control device) 12 receives the exhaust temperature from the engine exhaust temperature sensor 106, the engine speed from the engine rotation sensor 107, and the engine lubricating oil pressure from the engine oil pressure sensor 108, The coolant temperature is input from the engine water temperature sensor 109, the pressure of the common rail 1 is input from the rail pressure sensor 2, the boost pressure is input from the boost pressure sensor 149, the boost pressure control signal is input from the boost pressure correction control switch 150, A drive signal is output to the fuel high-pressure pump 4, and a fuel supply adjustment control signal is output to the high-pressure injector 6.

  Next, the work implement elevating system ECU 110 includes an operation signal for the position control sensor 111 provided on the work implement elevating lever, an elevating signal for the lift arm sensor 112, a raising position regulating signal for the raising position regulating dial 113, and a lowering speed adjustment. The lowering speed setting signal of the dial 114 is inputted, and the work implement raising / lowering signal is outputted to the main raising solenoid 115 and the main lowering solenoid 116 to operate the working implement raising / lowering cylinder.

Further, data is input to the work implement lifting system ECU 110 from the work implement ECU 151 and the communication unit 152.
The engine ECU 12, the work machine elevating system ECU 110, and a travel system ECU described later communicate control signals alternately (CAN 1, CAN 2 communication), and the meter panel 117 has an engine load state, a work machine elevating state, and a traveling device. And the operation position of each lever and pedal are displayed on the operation panel 118.

  The travel system ECU inputs a clutch engagement signal, that is, a gear position of a multi-stage gear transmission, from a shift 1 clutch pressure sensor 121, a shift 2 clutch pressure sensor 122, a shift 3 clutch pressure sensor 123, and a shift 4 clutch pressure sensor 124. That is, it is a signal of the first speed / third speed switching first transmission clutch 34 and the second speed / fourth speed switching second transmission clutch 35. The shift position of the sub clutch is input from the Hi (high speed) clutch pressure sensor 125 and the Lo (low speed) clutch pressure sensor 126. That is, the signal of the high / low speed switching clutch 50.

  From the forward clutch pressure sensor 127 and the reverse clutch pressure sensor 128, forward / neutral / reverse of the main clutch is input. That is, it is a signal of the forward / reverse switching clutch 27. A shift operation position signal is input from a forward / reverse lever operation position sensor 129 that detects the position of a forward / reverse lever that moves the tractor forward and backward, and an auxiliary transmission lever operation position sensor 130 that detects an operation position of the auxiliary transmission lever.

  The rotational speed is inputted from the rear wheel speed sensor 155 and the front wheel sensor 156, the temperature of the mission oil is inputted from the mission oil temperature sensor 132, and the depression signal of the clutch pedal is inputted from the clutch pedal operation position sensor 133. A standard engine output curve N and a low fuel consumption engine output curve S selection signal are input from the switch 134, and an engine control mode switching signal is input from the engine speed control mode switching switch 148.

  Furthermore, a signal is also input from an accelerator shift setting switch 144 that performs automatic shift (on the road) while the accelerator pedal is depressed, and an operation signal of a main shift increase / decrease operation switch 145 that manually increases / decreases the shift is input. The accelerator operation signal is input from the accelerator sensor 146 that detects the position of the accelerator lever, the accelerator adjustment signal of the accelerator fine adjustment lever sensor 147 that finely adjusts the accelerator is input, and the on / off signal is input from the low fuel consumption switch 134. A switching signal is input from the travel / work changeover switch 157, and the front / rear inclination angle of the vehicle body is input from the front / rear inclination sensor 160.

  As for the output from the travel system ECU, a forward / reverse switching clutch switching signal is output to the forward / reverse switching sol (solenoid) 135, and the hydraulic pressure relief pressure for driving the forward / reverse switching sol (solenoid) to the linear booster sol (solenoid) 136 is output. An adjustment signal is output to reduce the clutch connection shock, and an on / off signal is output to the clutch sol (solenoid) 137.

  Further, a first-speed or third-speed input signal is output to a shift 1-3 switching sol (solenoid) 138 of the hydraulic cylinder that drives the first-speed / three-speed switching first shift clutch 34, and the shift 1-3 boost sol ( Solenoid) 139 outputs a relief pressure adjustment signal for the hydraulic pressure that drives the first speed / third speed switching first shift clutch 34 to reduce the shock of clutch engagement. A second or fourth speed on signal is output to the shift 2-4 switching sol (solenoid) 140 of the hydraulic cylinder that drives the second shift clutch 35 for second / fourth speed switching, and the shift 2-4 boosting sol (solenoid) is output. 141 outputs a relief pressure adjustment signal for hydraulic pressure that drives the second speed / fourth speed switching second shift clutch 35 to reduce the shock of clutch engagement. A high-speed clutch input signal and a low-speed clutch input signal are supplied to the Hi (high-speed) clutch switching sol (solenoid) 142 and the Lo (low-speed) clutch switching sol (solenoid) 143 that operate the hydraulic cylinder that drives the high / low speed switching clutch 50. Output, a 4WD switching signal is output to the 4WDsol (solenoid) 158, and a switching signal is output to the front wheel acceleration clutch 79.

Next, the control of the forward / reverse switching clutch 27 during start-up running will be described.
After the brake pedal is released, the rear wheel 18 rolling is detected by the rear wheel speed sensor 155 for a short period of time, the forward / backward inclination sensor 160 determines whether the vehicle is going uphill or downhill, and the hydraulic pressure of the forward / reverse switching clutch 27 is increased. It gradually increases, but if it is an uphill, the starting oil pressure is set higher by a factor depending on the degree of rolling, and if it is a downhill, the starting oil pressure is set to the same value as the flat ground start by using the above coefficient. You can start smoothly and prevent starting.

FIG. 10 shows a configuration in which a front loader 165 and a bucket storage base 169 are mounted on the front portion of the tractor body 164.
The front loader 165 has a second arm 167 attached to the tip of the first arm 166 so that it can be bent, and a bucket 168 attached to the tip of the second arm 167.

  The first arm 166 can be expanded and contracted. When the bucket 168 has a height of 1 m or more and travels at a traveling speed of 10 km / h or more, the first arm 166 is contracted so that the bucket 168 is stored in the bucket storage base 169. Therefore, even if a load is loaded on the tractor body 164, the running is stable and the storage in the barn is facilitated.

A lateral pin may be provided on the bucket 168 and the lateral pin may be placed on a pin receiver provided on the bucket storage base 169 for storage.
A sensor may be installed at the doorway of the barn, and when this sensor is sensed on the tractor side, the first arm 166 may be contracted to easily enter and exit the barn.

Further, an expansion / contraction switch may be provided in the vicinity of the cockpit of the tractor body 164 so that the operator can adjust the expansion / contraction length of the first arm 166.
The first arm 166 may be contracted by releasing the hydraulic pressure of the raised bucket 168.

23 Engine load display means (drive torque monitor lamp)
9 Gear transmission 107 Engine load detection means (engine rotation sensor)
134 Fuel-saving switch K Specified speed

Claims (4)

  A low fuel consumption switch (134), an engine load detection means (109) and an engine load display means (23) are provided, and the low fuel consumption switch (134) is turned on based on the low load state displayed on the engine load display means (23). The tractor is characterized in that when the engine speed is changed, the engine speed is switched to a low speed (K).   The tractor according to claim 1, wherein the specified rotational speed (K) is an engine rotational speed during turning control.   The tractor according to claim 1, wherein the specified rotational speed (K) is an engine rotational speed at the time of reverse travel.   The engine speed is switched to a predetermined specified speed (K) when the low fuel consumption switch (134) is turned on, and the gear position of the gear transmission (59) is switched to the high gear position side. The tractor described in.

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