JP5076711B2 - Travel transmission for work vehicle - Google Patents

Description

  The present invention relates to a travel transmission device for a work vehicle that changes a travel speed by automatically shifting an in-transmission transmission mechanism of a travel device by operation of a hydraulic device in a work vehicle such as a tractor.

  The work vehicle can perform a rotary work or the like while traveling at an ultra-low speed as compared with the traveling speed during traveling on the road. This work vehicle incorporates a multi-stage or continuously variable transmission in the transmission case that transmits power from the engine to the traveling device, and reads the shift position of the shift lever provided near the steering operation seat to correspond to the shift position. As described above, the speed change device is operated to change speed by the operation of the hydraulic device, so that it can travel at a desired travel speed.

For example, Japanese Patent Laid-Open No. 2000-320644 discloses a main transmission comprising a hydraulic continuously variable transmission and a sub-transmission consisting of four gears, and a hydraulic transmission disclosed in Japanese Patent Laid-Open No. 2002-250437. A configuration is described in which a main transmission consisting of a continuously variable transmission and a sub-transmission consisting of three-stage gear shifting are incorporated in a transmission case. Shifting.
JP 2000-320644 A JP-A-2002-250437

  In the work vehicle described above, when the vehicle starts to travel, the gear transmission is generally set to the lowest speed and the continuously variable transmission is started from the lowest speed and gradually increased to a desired travel speed. There is a speed setting for working at an extremely low speed, and when starting from this extremely low speed setting, it takes a considerable time to reach a normal desired traveling speed.

  Therefore, according to the present invention, when the vehicle is traveling on the road, it is possible to shorten the time from the start to the desired traveling speed by setting the starting gear to an appropriate gear other than the lowest speed and starting the vehicle. Let's make it an issue.

The problems of the present invention are solved by the following technical means.
The invention according to claim 1 is provided with an auxiliary transmission lever (18) for setting the traveling speed to at least the traveling speed on the road, a traveling shift increase switch (33), and a traveling shift decrease switch (34), and the road switch (41) is provided. When the sub-shift lever (18) is driven on the road with the vehicle on, the automatic shift to the appropriate shift position is made from the amount of depression of the accelerator pedal and the engine speed when the road is running.
When the accelerator shift setting switch (52) is turned on and the sub-shift lever (18) is driven on the road, the start shift stage automatic change control is started and the start shift stage can be set before the start. (33) or by operating the travel shift lowering switch (34), the starting shift stage is changed, and the travel shift raising switch (33) and the travel shift lowering switch (34) do not turn on the road switch (41). A traveling transmission device for a work vehicle is characterized in that manual shifting during traveling is also possible .

The invention according to claim 2, the driving load determination means (D) provided, and configured to automatically change the outgoing advance gear position by this drive load determination means (D), the driving load determiner 2. The start shift speed set by operating the travel shift increase switch (33) or the travel shift decrease switch (34) is prioritized over the start shift speed according to (D). It was set as the traveling transmission apparatus of the described working vehicle.

The load state by the driving load determination unit D, and automatically changes the gear position at the time of calling proceeds. Then, the start shift stage set by operating the travel shift increase switch 33 or the travel shift decrease switch 34 is prioritized over the start shift stage by the drive load determination means D.

According to the first aspect of the present invention, when the work vehicle is equipped with a single or light work machine and the travel load is light, the travel shift increase switch (33) or the travel shift decrease switch (34) is operated. Since driving can be started by setting an appropriate starting speed other than the lowest speed , there is no backlash at the time of starting and the movement becomes light. The travel shift increase switch (33) and the travel shift decrease switch (34) are shared with the manual shift operation during traveling when the road switch (41) is not turned on.

According to the second aspect of the present invention, since the automatic start gear position by the load is changed, the steering operation becomes easy. In addition, since the start shift stage set by operating the travel shift increase switch (33) and the travel shift decrease switch (34) is prioritized over the start shift stage by the drive load determination means (D), the operator's determination is emphasized. Is done.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a tractor 1 as a working machine in which the present invention is implemented.
The tractor 1 has an engine 2 mounted on the front of the machine body, transmits the rotational power of the engine 2 to the transmission in the transmission case 3, and transmits the rotational power decelerated by the transmission to the front wheels 4 and the rear wheels 5. I am doing so. The area around the cockpit 6 on the fuselage is covered with a cabin 7.

  As shown in FIGS. 2 and 3, a steering handle 8 is erected on the front side of the cockpit 6 inside the cabin 7, and a forward / reverse lever 9 is provided on the lower right side thereof. On the left side of the cockpit 6, a parking brake lever 10 and a first PTO transmission lever 11 and a second PTO transmission lever 12 for shifting the PTO shaft that outputs power to the work implement are arranged.

  An accelerator pedal 13 for controlling the rotation of the engine is provided on the right floor surface of the steering handle 8. This accelerator pedal 1 is used to adjust the traveling speed. Further, on the front side of the steering handle 8, a panel 14 for displaying the traveling speed, the status of the working machine, and the like is provided.

  A control panel in which various levers and switches are centrally arranged is provided on the right side of the cockpit 6, a throttle lever 15 is provided at the front end thereof, and the rotation of the engine increases when it is tilted forward from the frontmost idling position. It is said. The throttle lever 15 is used when setting the engine speed during operation. Reference numeral 16 denotes a seesaw-type first engine rotation storage switch. When the switch is tilted upward, the first stored rotational speed is obtained. When the switch is tilted downward, the second stored rotational speed is obtained, and when the finger is released, the position returns to the neutral position. Reference numeral 17 denotes a seesaw-type second engine rotation storage switch. When the switch is tilted upward, the rotational speed increases. When the switch is tilted downward, the rotational speed decreases, and the rotational speed when the switch is released is stored. To set the rotation speed, the first engine rotation storage switch 16 is tilted upward or downward, and the second engine rotation storage switch 17 is tilted upward or downward to increase or decrease the rotational speed. When released, the number of rotations at that time is stored.

  Next to the throttle lever 15, an auxiliary transmission lever 18 corresponding to the travel type setting means of the present invention is provided. The sub-shift lever 18 has three speeds, low speed, medium speed, and high speed, and a road shift position. The mechanical speed changer in the transmission case 3 is shifted to low speed, medium speed, and high speed to the road travel position. Then, the speed is changed with the number of travel stages suitable for road traveling by a combination of a main speed, which will be described later, and low speed, medium speed, and high speed.

  The main gear shift is a combination of high and low two gear shifts by hydraulic control, as well as four gear shifts by hydraulic control, and has a total of eight gear stages, and the average vehicle speed by the gear stages is as shown in the chart of FIG. In combination with the low speed, medium speed, and high speed of the sub-shift lever 18, a total of 24 speeds are provided. In normal road travel, the sub-speed is set to a high speed and the main speed is set to 3 or more. ing.

  Reference numerals 19 and 20 are two sub-control levers for taking out external hydraulic pressure provided at the rear of the auxiliary transmission lever 18 and are used when hydraulic oil is supplied to a hydraulic cylinder or the like of the working machine. Reference numerals 21 and 22 are auxiliary sub-control lever mounting grooves. Reference numeral 23 is a draft ratio adjustment dial that is configured to mix so-called position control and draft control. When turned counterclockwise, the position becomes the position side, and the amount of change in the lifting and lowering of the work implement with respect to the load is reduced, so that the tilling depth is reduced. On the contrary, when it is turned to the right, it becomes the draft side, and the amount of change in the lifting / lowering of the work implement with respect to the load increases, thereby increasing the tillage depth.

  Reference numeral 24 denotes a raising adjustment dial. When the dial 24 is turned counterclockwise, the elevation height of the three-point link is lowered. Depending on the working machine, when it is raised to the highest level, when it hits the main body of the tractor or when working efficiency is better when it is not raised too much, the raising adjustment dial 24 adjusts. Reference numeral 25 denotes a tilt adjustment dial. When the dial is turned counterclockwise, the work implement moves up to the right, and conversely when turned clockwise, the work implement goes down.

  Reference numeral 26 is a four-WD changeover switch, where “travel loader” and “super full turn” and “two WD turn” positions are sequentially provided. In the “travel loader” position, only two rear wheels are normally driven. However, it becomes muddy, steep hills or uneven roads, and automatically switches to 4WD, and even if the brake is applied or stopped during operation, it becomes 4WD. Two-WD is a rear-wheel two-wheel drive, and four-WD is a front-rear four-wheel drive. At the “Super Full Turn” position, the speed of the front wheel is increased by turning at the 4WD, and a small turn is possible, and at the “2WD Turn” position, the driving of the front wheel is removed by the turning at the 4WD. This makes it possible to turn smoothly in a small turn on a hard field.

  Reference numeral 27 denotes a horizontal cylinder raising / lowering switch, which can operate a horizontal cylinder of a three-point link and is used for rolling control of the work machine. Reference numeral 28 denotes a PTO switch. When it is pushed and turned to the right, the PTO clutch is engaged, and when it is pushed in, the PTO clutch is automatically turned to the left and the PTO clutch is disengaged. Reference numeral 29 denotes a PTO automatic switch, which is manually turned when turned to the left and always rotates when the clutch is engaged, and automatically turned when turned to the right and stops rotating when the travel clutch is stepped on or the three-point link is raised. This PTO automatic switch 29 is mainly used during paddy field work.

Reference numeral 30 denotes a diff lock switch. When it is pushed outward once, it becomes diff lock, and when it is pushed outward again, the diff lock is released. It cannot be pushed inward, but switches each time it is pushed outward.
Reference numeral 52 denotes an accelerator shift setting switch. When the accelerator shift setting switch 52 is pressed, the gear position at the start is automatically changed. The automatic change control of the starting shift stage may be started by removing the accelerator shift setting switch 52 and causing the auxiliary transmission lever 18 to travel on the road.

  Various levers and switches are also provided on the armrest. For example, reference numeral 31 denotes a work implement lifting lever, which is lowered when it is tilted forward, and the rear side is raised. Reference numeral 32 denotes a work implement raising / lowering switch, which is raised to the uppermost position set by the raising adjustment dial 24 by pushing the rear side once, and lowered to the position set by the work implement raising / lowering lever 31 by pushing the front side once.

  Reference numerals 33 and 34 are travel shift raising / lowering switches corresponding to the shift speed setting means of the present invention, each time the travel shift increase switch 33 is pressed once, the start shift stage is shifted up, and each time the travel shift decrease switch 34 is pressed once. Shift down the starting gear. The travel shift raising / lowering switches 33 and 34 are configured so that the start shift stage can be changed up and down in the same manner when the sub shift lever 18 is driven on the road, with the sub shift being at a high speed and the main shift being based on the third speed. ing. As described above, since the first shift speed at which the vehicle starts to start can be arbitrarily set according to the situation, the operability is improved.

  For example, when it is determined that the weight of the vehicle body is light, the load at the start of traveling is in a small state, so that the traveling can be started by arbitrarily setting a speed other than the first speed (second speed to fourth speed, etc.) This makes it possible to prevent slack in the fuel and improve fuel efficiency. Regarding the weight change of the vehicle body, the work machine to which the vehicle body is attached occupies a large weight. In addition, the amount of fuel in the fuel tank is also affected and should be taken into consideration.

  Regarding the setting method of speeds other than the first speed (second speed to fourth speed, etc.), for example, after the sub-shift lever 18 is traveled on the road, the travel shift up / down switches 33 and 34 are set before starting the clutch pedal. It is changed by operating. Further, in order to prevent an erroneous operation, another switch may be operated at the same time as the travel shift up / down switches 33 and 34. Further, in this way, it may be configured to display on the monitor or the like that the shift stage at the time of starting is changed, or to notify by voice guidance.

The travel shift raising / lowering switches 33 and 34 can also perform shifts (shifting up and down) during traveling.
Further, when the travel type setting means 18 is configured to automatically change the start gear stage according to the travel load without manually setting the start gear stage at the start of driving when traveling on the road, the maneuvering operation is simple. become.

For example, if the decrease in engine speed is more noticeable than the normal load when attempting to start, the speed at the time of starting is automatically set to a low speed (first speed).
Reference numeral 36 denotes a switch box. When the lid is opened, various adjustment switches shown in FIG. 3 are arranged. Reference numeral 37 denotes a work machine ascent / descent monitor lamp which is lit and displayed when the work machine is raised and lowered. Reference numeral 38 denotes an AT shift sensitivity dial which changes the sensitivity for increasing or decreasing the vehicle speed when the AT work switch 42 is pressed to enter the automatic shift mode.

  Reference numeral 39 denotes a descent speed dial for adjusting the descent speed of the work machine. When the dial is turned to the right, the work machine descends faster, so it is used for a light work machine. Conversely, turning to the left slowly lowers the work machine. So use it for heavy working machines.

Reference numeral 40 denotes a travel brake adjustment dial, which adjusts the degree of application of the turning brake that is applied when the auto brake on / off switch 48 is turned on.
Reference numeral 41 denotes an AT shift road switch. When turned on, the automatic shift is automatically made to an appropriate shift position based on the accelerator pedal depression amount and the engine speed when traveling on the road. Automatic shift to the correct shift position.

  Reference numeral 43 is a main gear connection sensitivity shift switch, which changes the connection feeling when the main gear shift is changed. When the switch is turned on, the monitor is turned on and the gear is gradually changed. When the connection sensitivity shift switch 43 is turned off and a pulling operation such as a plow is performed, the shift connection time of the main shift is shortened and the operation can be performed lightly.

  Reference numeral 44 denotes a connection sensitivity PTO switch. In this embodiment, there are “rotary”, “grass 1”, and “grass 2”. When “rotary” is selected, the connection of PTOs becomes fast, and the rotary does not lose the resistance of soil immediately. When turning to grass 1 or grass 2, the PTO connection becomes loose and it is used with grass working machines and snow blowers.

Reference numeral 45 denotes a horizontal sensitivity switch. The operation sensitivity of the automatic horizontal control device changes. When the switch is pressed, the automatic horizontal control moves slowly, and when the switch is pressed again, the operation returns.
Reference numeral 46 denotes a backup on / off switch. When it is turned on, the work implement is automatically raised when the vehicle is moved backward. Reference numeral 47 is an auto lift on / off switch. When the handle is turned on with the auto lift turned on, the working machine is automatically raised. Reference numeral 48 denotes an auto brake on / off switch. When the handle is turned on with the brake turned on, the brake is automatically applied only to the rear wheel inside the turn.

  Reference numeral 49 denotes a horizontal changeover switch. When the level is automatically set, the level sensor automatically holds the level. When the level is set manually, the tilt adjustment dial 25 can be adjusted. When the level is parallel, the three-point link is always connected to the tractor body. When kept parallel and inclined, the three-point link maintains a constant inclination angle with respect to the ground.

Reference numeral 50 denotes a 3P changeover switch, which performs control changeover selection based on the lift cylinder mounting position to the three-point link.
Reference numeral 51 denotes an auto accelerator switch. When the work implement is raised in the on state, the engine speed is reduced to a preset low rotation, for example, 1700 rpm.

Next, the flow of control signals will be described with reference to the control block diagram of FIG.
First, the engine controller 60 receives the exhaust temperature from the engine exhaust temperature sensor 61, the engine speed from the engine rotation sensor 62, the engine lubricating oil pressure from the engine oil pressure sensor 63, and the engine water temperature sensor 64. The temperature of the cooling water enters, a fuel supply adjustment control signal is output to the governor actuator 65, and a drive signal is output to the fuel pump 66.

  Next, an operation signal for the work implement elevating lever 31, an elevating signal for the lift arm sensor 68, a raising position restriction signal for the raising adjustment dial 24, and a lowering speed setting signal for the lowering speed dial 39 are input to the working implement raising / lowering controller 67. Then, a work implement lift signal is output to the main lift solenoid 69 and the main drop solenoid 70 to operate the work lift cylinder 71.

  The engine controller 60, the work implement elevating controller 67, and a travel system controller 87, which will be described later, communicate with each other, and the engine panel, the elevating state of the work implement, the travel speed of the travel device, and the like are displayed on the meter panel 72. The operation position of each lever and pedal is displayed on the panel 73.

  A clutch engagement signal is input to the traveling system controller 87 from the shift 1 clutch pressure sensor 74, the shift 2 clutch pressure sensor 75, the shift 3 clutch pressure sensor 76, and the shift 4 clutch pressure sensor 77, respectively. Respective clutch engagement signals are input from the clutch pressure sensor 79, forward clutch pressure sensor 80, and reverse clutch pressure sensor 81, and shift operation position signals are input from the forward / reverse lever operation position sensor 82 and the auxiliary shift lever operation position sensor 83, The traveling speed of the aircraft is input from the vehicle speed sensor 84, the temperature of the mission oil is input from the mission oil temperature sensor 85, the depression signal of the clutch pedal is input from the clutch pedal operation position sensor 86, and is input from the accelerator shift setting switch 52.・ When a cut signal is input, the traveling speed increases Setting signal is inputted from the switch 33, the depression signal is input from the accelerator pedal sensor 54.

  Further, the depression speed of the accelerator pedal 13 and the engine speed increase rate are input from the travel system controller 87 to the drive load determination means D, and the determination result of the drive load is transmitted from the drive load determination means D to the travel system controller 87. The driving load determination method of the driving load determination means D will be described later.

  From the travel system controller 87, a forward / reverse switching clutch switching signal is output to the forward / reverse switching solenoid 89, and a hydraulic relief pressure adjustment signal for driving the forward / reverse switching solenoid 89 is output to the linear boosting solenoid 89 to connect the clutch. Shock is reduced, a 1st or 3rd speed input signal is output to the shift 1-3 switching solenoid 91, and a hydraulic pressure relief pressure adjustment signal for driving the 1-3th clutch is output to the shift 1-3 boost solenoid 92. This reduces the shock of clutch engagement, outputs a 2nd or 4th speed input signal to the shift 2-4 switching solenoid 93, and adjusts the relief pressure of the hydraulic pressure that drives the 2-4th clutch to the shift 2-4 boost solenoid 94 A signal is output to reduce clutch connection shock, and a high-speed clutch input signal is output to the high-speed clutch switching solenoid 95 to switch the low-speed clutch. Input signal of the low-speed clutch is outputted to the solenoids 96.

  Next, the accelerator shift control by turning on the accelerator shift setting switch 52 will be described with reference to the control flowchart of FIG. As already described, the accelerator shift control is an automatic change control of the starting shift stage, and the control is started by turning on the accelerator shift setting switch 52 and causing the auxiliary shift lever 18 to travel on the road. Yes.

  First, in step S1, the input signals of the sensors such as the engine rotation sensor 62 and the switches such as the accelerator shift setting switch 52 are read. In step S2, the control information is transmitted from the engine controller 60 and the work implement lifting controller 67 to the traveling system controller 87. Is read.

  Next, in step S3, it is determined whether the accelerator shift setting switch 52 is turned on. If YES, it is determined in step S4 whether the auxiliary transmission lever 18 is on the road traveling position. If YES, the process proceeds to step S5. If both step S3 and step S4 are NO, the process returns without doing anything. It should be noted that the determination of whether or not the accelerator shift setting switch 52 is turned on may be eliminated and only the determination of whether or not the auxiliary transmission lever 18 is on the road traveling position may cause the process to proceed to step S5.

  In step S5, it is determined whether or not it is immediately after shifting to road driving. If YES, the road driving initial position (high speed / third speed) is controlled in step S6, and if NO, the process proceeds to the determination in step S7.

In step S7, the position of the forward / reverse lever 9 is determined. If neutral, the process proceeds to step S13, if forward, the process proceeds to step S8, and if reverse, the process returns without doing anything.
In step S14, the operation of the travel shift raising / lowering switches 33, 34 is determined, and if there is an operation (YES), the main gear position is changed in step S15 according to the operation. In step S16, the main shift speed is stored as the minimum shift speed when traveling on the road, and the process returns.

  In step S8, the driving is started, that is, started at the starting shift speed stored in step 16 in the initial setting (high speed / third speed) or the previous control loop. Since this starting start uses the lowest gear stored in step S16 at the next starting, the determinations in steps S10 and S12 are often NO, and the processing is accelerated. Thereafter, in step S9, the main shift is controlled to increase or decrease to the optimal shift position according to the accelerator shift, that is, the amount of depression of the accelerator pedal 13 and the engine speed by operating the throttle lever 15.

  Further, the load at the time of start is determined at step S10, and if the load at the drive load determination means D is large, the transmission shift stage of the main shift is lowered by one step at step S11, the process proceeds to step S16, and at the time of start at step S12 In the load determination, if the load on the drive load determination means D is extremely small, the transmission shift stage of the main shift is raised by one step in step S13, the process proceeds to step S16, and the process returns. In addition, since the load determination by the driving load determination means D is performed every time in the control loop, if a work implement having a different weight is attached to the tractor, the start gear is changed according to the traveling load.

  The load at the time of starting by the drive load determining means D is the case where the engine rotation is difficult to follow the rotation increase command from the accelerator pedal 13, that is, the engine speed increases only slowly even when the accelerator pedal 13 is depressed, or When the idling rotation decreases at the time of starting, it is determined that the load is large, and when the engine rotation immediately increases in response to the rotation increase command from the accelerator pedal 13, that is, when the accelerator pedal 13 is depressed, the engine rotation immediately increases. It is judged that the load is extremely small. Specifically, the depression speed of the accelerator pedal 13 and the rate of increase of the engine speed are monitored to determine that the engine increase rate is a light load when the engine increase rate is greater than a certain value, and the heavy load is the following. The drive load determination means D is limited even if this output increase is performed when the engine load is monitored and control is performed to increase the fuel supply and increase the output in the case of an overload. It may be determined that the load is heavy.

  In the control described above, the input of the travel shift raising / lowering switches 33 and 34 can be prioritized over the automatic control so that the operator's drive load determination is more important than the determination by the drive load determination means D.

  Further, when the auxiliary transmission lever 18 is driven on the road, the control is automatically started. However, the automatic control can be canceled and the engine can be started at the starting shift stage by the traveling shift raising / lowering switches 33 and 34.

The whole tractor side view. 1 is an overall plan view of a tractor showing an embodiment of the present invention. The partial expansion perspective view of a tractor. The block diagram of control. The flowchart of control. FIG. 4 is an explanatory table of gear positions.

18 Sub-shift lever (travel type setting means)
33 travel shift up switch 34 travel shift down switch
41 road switch
52 Acceleration shift setting switch D Drive load determination means

Claims (2)

A sub-transmission lever (18) for setting the travel speed to at least the road travel speed, a travel shift increase switch (33), and a travel shift decrease switch (34) are provided. The road switch (41) is turned on to turn on the sub-transmission lever (18). When driving on the road, it automatically shifts to the appropriate shift position from the accelerator pedal depression amount and engine speed when driving on the road,
When the accelerator shift setting switch (52) is turned on and the sub-shift lever (18) is driven on the road, the start shift stage automatic change control is started and the start shift stage can be set before the start. (33) or by operating the travel shift lowering switch (34), the starting shift stage is changed, and the travel shift raising switch (33) and the travel shift lowering switch (34) do not turn on the road switch (41). A traveling speed change device for a work vehicle, characterized in that manual shifting during traveling is also possible . The driving load determination means (D) provided automatically configured to change the outgoing advance gear position by this drive load determination means (D), the traveling than the starting gear position by the driving load determination unit (D) The traveling transmission apparatus for a work vehicle according to claim 1, wherein the traveling gear stage is configured to give priority to the starting shift stage set by operating the shift raising switch (33) or the traveling shift lowering switch (34) .

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