JP6090068B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle such as a tractor for agriculture, construction, and transportation.

  A work vehicle such as a tractor performs a shift operation using a main shift lever and a sub shift lever, which are shift operation members. A maximum speed setting dial is provided in the work vehicle, and the maximum speed set by the maximum speed setting dial is provided. There is known a configuration in which the above speed cannot be obtained and safe driving is performed.

JP 2008-279945 A

  In the work vehicle of Patent Document 1, safe driving can be performed by performing a speed change operation at a speed equal to or lower than the speed set with the maximum speed setting dial, but there is no means for storing the maximum speed set with the maximum speed setting dial. When using it, it was necessary to reset it every time.

  An object of the present invention is to provide a safe traveling vehicle with excellent maneuverability, which does not need to be reset to the maximum speed set by the maximum speed setting dial or the slow response speed set by the vehicle speed slow response dial.

The above-described problems of the present invention are solved by the following solution means.
The invention described in claim 1 includes an engine (5) mounted on a traveling vehicle body (1), engine speed detection means (5a) for detecting the speed of the engine (5), and the engine (5). The trunnion shaft (30) having a swash plate (34d) capable of changing the inclination angle by operating the hydraulic pump (34a) and the output corresponding to the inclination angle of the swash plate (34d). A hydrostatic transmission (34) for driving (35), a gear-engaged multiple-stage auxiliary transmission (38) that receives the rotational power of the hydraulic continuously variable transmission (34), and Traveling wheels (2 and / or 3) driven by the output of the auxiliary transmission (38), auxiliary transmission operating means (21) for operating the auxiliary transmission by the auxiliary transmission (38) to the low speed side and the high speed side, Forward or reverse direction of the trunnion shaft (30) A forward / reverse lever (10) for switching the forward or reverse rotation of the traveling wheel (2 and / or 3) according to the rotation angle, and a forward / reverse lever position sensor for detecting the operation position of the forward / reverse lever (10) The accelerator pedal (15) for changing the output amount of the hydrostatic transmission (34) by changing the rotation angle of the trunnion shaft (30) corresponding to the combination or the depression amount of (10c) and the accelerator pedal (15 The maximum speed of the vehicle body (1) is regulated by adjusting the rotation angle of the trunnion shaft (30) of the hydraulic continuously variable transmission (34) and the combination of the accelerator pedal detection means (15a) for detecting the depression amount of A maximum speed setting dial (14a), a vehicle speed slow response dial (14b) for setting the rotation angle of the trunnion shaft (30) of the hydraulic continuously variable transmission (34) to a vehicle speed slow response speed, Provided with a setting dial controller having a memory (90) for storing the set position of (14a) and the vehicle speed slow response dial (14b) (100), connects the working machine to the vehicle body (1), said working machine A PTO shaft (55 or 56) for transmitting engine power is provided on the lower side of the auxiliary transmission (38), and the rotational speed of the PTO shaft (55 or 56) is set to the maximum speed setting dial (14a) and the vehicle speed slow response. A PTO dedicated switch (19) that can be set by a dial (14b) is provided, and when the PTO dedicated switch (19) is input, the operation of the work implement is set to the set value of the maximum speed setting dial (14a) or the vehicle speed slow response dial (14b ) it is a working vehicle, characterized in that a control arrangement to correspond to the set value of the control device (100).

  The invention according to claim 2 is characterized in that the memory (90) can store a plurality of set values for the maximum speed setting dial (14a) and a set value for the vehicle speed slow response dial (14b). The traveling vehicle according to Item 1.

According to a third aspect of the present invention, the traveling vehicle body (1) is provided with the front / rear inclination sensor (26) of the traveling vehicle body (1), and the front wheel (2) on which the front / rear inclination sensor (26) is preset floats off the ground. The control device (100) is provided with a control configuration for reducing the engine speed set by the maximum speed setting dial (14a) and the vehicle speed slow response dial (14b) by a preset value when an inclination is detected. a working vehicle according to claim 1 or 2, characterized.

According to the first aspect of the present invention, the control device (100) having the memory (90) for storing the setting positions of the maximum speed setting dial (14a) and the vehicle speed slow response dial (14b) is provided. The maximum speed set by the high-speed setting dial (14a) and the vehicle speed slow response dial (14b) and the vehicle speed slow response speed can be easily reproduced, so that the operability of the work vehicle is improved as compared with the prior art.
According to the first aspect of the present invention, the operation of the work implement can be made to correspond to the set value of the maximum speed setting dial (14a) or the set value of the vehicle speed slow response dial (14b) by the PTO dedicated switch (19). This improves operability and versatility of work.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the memory (90) sets the set value of the maximum speed setting dial (14a) and the set value of the vehicle speed slow response dial (14b), respectively. Since a plurality of data can be stored, the operability of the traveling vehicle is further improved than before.

According to the third aspect of the invention, in addition to the effect of the invention according to claim 1 or 2, increases driving safety in uphill.

It is a side view of the tractor of the Example of this invention. It is a top view of the tractor of FIG. It is a power transmission mechanism diagram of the transmission of the tractor of FIG. FIG. 2 is a hydraulic circuit diagram of the hydrostatic continuously variable transmission of the tractor of FIG. 1. It is a control block diagram of the tractor of FIG. It is an enlarged view of the lever guide part of the tractor of FIG. It is an enlarged view of the operation panel of the tractor of FIG.

Embodiments of the present invention will be described with reference to the drawings.
Hereinafter, a tractor will be described as an example of a work vehicle. FIG. 1 (FIG. 1 shows a view without a front loader) shows an overall side view, and FIG. 2 shows a plan view of the tractor of FIG. 1 (excluding the cabin). 3 is a power transmission mechanism diagram of the tractor transmission of FIG. 1, FIG. 4 is a hydraulic circuit diagram of the hydrostatic continuously variable transmission of the tractor of this embodiment, and FIG. 5 is a control of the tractor of this embodiment. It is a block diagram.

In this specification, the left and right directions in the forward direction of the work vehicle are referred to as left and right, respectively, the forward direction is referred to as front, and the reverse direction is referred to as rear.
The tractor shown in FIGS. 1 and 2 includes front wheels 2 and 2 and rear wheels 3 and 3 at the front and rear portions of the traveling vehicle body 1, and the rotational power of the engine 5 mounted on the front portion of the vehicle body 1 is transmitted by a transmission in the transmission case. The vehicle is configured to be appropriately decelerated and transmitted to the front wheels 2 and 2 and the rear wheels 3 and 3.

A steering handle 7 is supported on the handle post 6 in the center of the vehicle body 1, and a seat 9 is provided behind the steering handle 7.
As shown in FIG. 1, the fuel tank 8 is stored in the bonnet 22, and the rear side of the fuel tank 8 main body is stored in the handle post 6.

  A forward / reverse lever 10 that switches the traveling direction of the vehicle body 1 to the front / rear direction is provided below the steering handle 7. When the forward / reverse lever 10 is moved forward, the vehicle body 1 moves forward, and when it is moved backward, it moves backward. A throttle lever 11 for changing the engine speed is provided on the opposite side of the forward / reverse lever 10 with the handle post 6 in between. An accelerator pedal 15 and left and right brake pedals 16 are provided at the right corner of the step floor 13. , 16 are arranged. The accelerator pedal 15 is basically used when traveling on the road, the engine speed increases according to the amount of depression, and the amount of depression of the accelerator pedal 15 is detected by an accelerator pedal position sensor 15a (FIG. 5). The rotation angle of the trunnion shaft 30 (FIG. 4) of the hydrostatic continuously variable transmission (HST) 34 can be changed by the trunnion hydraulic proportional valve 65 in accordance with the detected value of the accelerator pedal position sensor 15a. The output of the HST can be continuously changed steplessly by changing the inclination angle of the swash plate 34d (FIG. 4) according to the rotation angle of the trunnion shaft 30.

  The throttle lever 11 is used to change the engine speed and is used during work travel. The throttle lever 11 is configured so that the position is maintained even if the hand is released at the operated position. Further, a sub-shifting lever 21 that can select any of low speed, medium speed, high speed, and neutral position is arranged on the left side of the cockpit 9 and is mounted behind the front wheel 2 and the rear wheel 3 behind the mid work. A mid PTO speed change lever 23a for turning on and off the PTO shaft of a machine (moor etc.) and a PTO shaft on and off of a working machine (mower, rotary, snowplow etc. (not shown)) mounted on the rear part of the machine body. A rear PTO speed change lever 23b is provided. A link 31 for connecting a work machine (not shown) is provided behind the vehicle body 1.

  The rotational power of the engine 5 is transmitted from the HST input shaft 33 to the HST 34. Further, the hydraulic pump 34a shown in FIG. 4 is operated by the power introduced from the HST input shaft 33, and pressure oil corresponding to the inclination angle of the swash plate 34d provided in the hydraulic pump 34a is supplied from the hydraulic closed circuit 34c to the hydraulic motor. The driving output shaft 35 is driven by the hydraulic motor 34b to transmit power to the meshing transmission 38.

As shown in FIG. 3, in the auxiliary transmission clutch shifter 39 of the meshing transmission 38, the rotation of the transmission shaft 43 is driven through the differential device 46 and the rear wheel 3 is driven at the traveling speed of the auxiliary transmission high speed stage.
The power output from the HST 34 is transmitted from the travel output shaft 35 to the rotary shaft 36. The gear position by the transmission 38 is set as follows. That is, in the sub-speed stage (third speed), the power changed by the gear 38 b from the gear 38 a is transmitted to the transmission shaft 43. In addition, in the sub-speed middle speed (second speed), the power shifted from the gear 38c by the gear 38d is transmitted to the transmission shaft 43, and in the sub-speed lower speed (first speed), the gear 38e is shifted by the gear 38f. Power is transmitted to the transmission shaft 43. These three sub-shifts are switched by operating the sub-shift lever 21 and sliding the shifter 39 left and right. The rotation of the transmission shaft 43 is driven through the differential device 46 so that the rear wheel 3 is driven at the traveling speed of the sub-shift middle speed.

  On the other hand, power input from the HST input shaft 33 to the variable displacement hydraulic pump 34a (FIG. 4) is provided to the PTO shaft 52 from the pump output shaft 51 (shown only in FIG. 3) via the PTO hydraulic clutch 54 and the like. Is transmitted to the drive system for the PTO. Power is transmitted from the PTO shaft 52 to the rear PTO shaft 55 and the mid PTO shaft 56.

  Also, the gear 58 on the lower side of the sub-shift of the transmission shaft 43 is transmitted to the gear 57 of the front wheel output shaft 48 via the gear 47 of the PTO shaft 52 and the gear 59 integral with the gear 47, and the front wheel 2 is driven. The

Further, when a loader (not shown) is attached to the front or rear of the vehicle body 1, the loader is raised and lowered by a loader lifting cylinder (not shown).
The hydrostatic continuously variable transmission (HST) 34 has a rotational speed of the trunnion shaft 30 set by the control device 100 according to the rotational angle of the trunnion shaft 30 (FIG. 4), that is, the rotational angle of the swash plate 34d. Although the detailed description is omitted, when the depression amount of the accelerator pedal 15 is detected by the accelerator pedal position sensor 15a, the operation amount (the number of rotations) of the trunnion shaft 30 according to the detected value of the accelerator pedal position sensor 15a. Is automatically set by the control device 100 by the trunnion hydraulic proportional valve 65, and the hydraulic pressure output of the hydrostatic continuously variable transmission (HST) 34 is automatically set to an appropriate value.

  In addition, the control device 100 operates the hydrostatic continuously variable transmission by a method such as operating a changeover switch (not shown) provided at the rotation base of the forward / reverse lever 10 by switching the forward / reverse lever 10 to the forward side or the reverse side. The rotation direction of the trunnion shaft 30 of the device (HST) 34 is set to the forward side or the reverse side. The turning direction of the trunnion shaft 30 is determined by the switching valve 63 (FIG. 4). Then, the rotation angle of the trunnion shaft 30 changes according to the depression amount of the accelerator pedal 15. The rotation angle of the trunnion shaft 30 is determined by the amount of current to the solenoid valve of the trunnion hydraulic proportional valve 65.

  Further, in the event of an emergency such as a valve stick, the HST trunnion shaft 30 can be forcibly returned to neutral by fully depressing the brake pedals 16 and 16 in the control section. When the brakes 16 and 16 are stepped on, the operator removes his / her foot from the accelerator pedal 15, so the trunnion shaft 30 returns to neutral. At this time, whether the trunnion shaft 30 returns naturally or forcibly returns at a high speed differs depending on the model.

  In the hydraulic circuit 34c of the HST 34 shown in FIG. 4, when a valve or the like is clogged with impurities (valve stick), an emergency stop lever (not shown) in the control section is pulled to return the trunnion shaft 30 of the HST 34 to neutral. . FIG. 5 shows a control block diagram of the tractor control apparatus 100 of this embodiment.

  As shown in the overall plan view of the tractor shown in FIG. 1, a throttle lever 11 (FIG. 2) and a forward / reverse lever 10 are arranged on the left and right on the handle post 6 around the handle 7. An accelerator pedal 15 is disposed on the step floor 13 on the right side of the throttle lever 11. The accelerator pedal 15 can adjust the rotation angle of the trunnion shaft 30 of the HST 34.

  Further, the lever guide 12a on the right side of the cockpit 9 is provided with a maximum speed setting dial 14a, a vehicle speed slow response dial 14b, and a cruise travel switch 14c arranged in a line in order from the front side to the rear side. The dials 14a and 14b and the switch 14c need only be arranged in a line in the front-rear direction, and the arrangement order of the dials 14a and 14b and the switch 14c is not particular.

  The maximum speed setting dial 14a is a dial type, and regulates the maximum speed of the vehicle body by adjusting the rotation angle of the trunnion shaft 30. For example, the maximum speed setting dial 14a is set so that the operator can determine a predetermined maximum speed. It is set as the structure which can be changed into a dial type in the range of 15-30 km / h. Therefore, even when the accelerator pedal 15 is depressed to the maximum, only the speed regulated by the maximum speed setting dial 14a can be obtained (the sensor value of all strokes of the maximum speed setting dial 14a and the sensor of all strokes of the rotation of the trunnion shaft 30). Configuration to match values).

  The vehicle speed slow response dial 14b also changes and sets the rotation speed of the trunnion shaft 30. When the accelerator pedal 15 is depressed, the target speed of the accelerator pedal position sensor 15a, that is, the rotation angle of the target trunnion shaft 30 is determined. The trunnion shaft is positioned at the position of the rotation angle of the target trunnion shaft 30. The time which 30 reaches | attains is changed. For example, if the vehicle speed slow response dial 14b is made insensitive (slow), even if the accelerator pedal 15 is stepped on quickly, the time required to reach the target rotation angle of the trunnion shaft 30 will be slow. It is a composition to go. The change of the arrival time to the target position is performed by changing the duty ratio of the current to the trunnion hydraulic proportional valve 65 (FIG. 4). The time until the vehicle speed slow response dial 14b reaches a predetermined vehicle speed can be changed to a dial type from about 3 seconds to about 6 seconds, for example.

  The cruise travel switch 14c is an on / off switch. If the cruise travel switch 14c is turned on while traveling at a specific speed, the speed at that time is maintained even if the accelerator pedal 15 is released. It is a configuration. That is, the cruise travel switch 14c keeps the rotation angle of the trunnion shaft 30 constant so as to match the vehicle speed when the cruise travel switch 14c is turned on, so the output of the HST 34 is kept constant and the vehicle speed is kept constant. Is done. Even if the foot is released from the accelerator pedal 15 after the cruise travel switch 14c is turned on, the speed at that time is maintained.

  As described above, the turning angle of the trunnion shaft 30 of the HST 34 is set to any one of three preset types by simply turning on any of the maximum speed setting dial 14a, the vehicle speed slow response dial 14b, and the cruise travel switch 14c. Therefore, the maneuverability is improved as compared with the case where the dials 14a and 14b and the switch 14c are not provided. In addition, since the dials 14a and 14b and the switch 14c are arranged in a line in the front-rear direction adjacent to the cockpit 9, the selection of the dials 14a and 14b and the switch 14c is not lost, and the target dial and switch Can be put in quickly.

  The dials 14a and 14b and the switch 14c are collectively called a servo switch, but the highest speed setting is set from the front side to the rear side in order to line up the right lever guide 12a adjacent to the cockpit 9 in the front-rear direction. You may arrange | position in order of the dial 14a, the cruise travel switch 14c, and the vehicle speed slow response dial 14b.

  The maximum speed setting dial 14a and the vehicle speed slow response dial 14b can be stored in the memory 14a of the control device 100, and the maximum speed and the vehicle speed slow response speed can be started from the stored value of the memory 14a at the next use.

  In the prior art, since the basic values set by the maximum speed setting dial 14a and the vehicle speed slow response dial 14b are set each time by the dials 14a and 14b, it is desired to set the speed which has been set previously. I couldn't. However, in this embodiment, the maximum speed and the slow response speed set by the dials 14a and 14b can be stored in the memory 90, respectively.

  That is, as shown in FIGS. 2 and 6, a memory 1 switch 17 is provided on the right side of the right lever guide 12a adjacent to the cockpit 9, and the memory 1 switch 17 is pressed and held long, whereby the highest speed setting dial 14a. And the values respectively set by the vehicle speed slow response dial 14b can be stored. Further, by pressing the memory 1 switch 17 for a short time, the stored values respectively set by the maximum speed setting dial 14a and the vehicle speed slow response dial 14b can be executed. It should be noted that when the memory 1 switch 17 is pressed for a short time, the memory 1 switch 17 is lit so that it can be easily recognized.

  Thus, at the time of the next work, there is an advantage that the dials 14a and 14b can be operated with the values of the dials 14a and 14b used last time without setting again when the dials 14a and 14b are used, and the operability is improved as compared with the prior art.

  In addition, if a plurality of maximum speeds and slow vehicle speeds set by the dials 14a and 14b can be stored in the memory 90, a plurality of basic set values can be set in accordance with the work system, and the operability is improved according to the prior art. More improved.

  By depressing the memory 2 switch 18 for a long time, the current depression amount of the accelerator pedal 15 can be stored. Further, by pressing the memory 2 switch 18 for a short time, the stored value set by the depression amount of the accelerator pedal 15 can be executed. It should be noted that when the memory 2 switch 18 is pressed for a short time, the memory 2 switch 18 is lit so that it can be easily recognized.

  Thus, at the time of the next work, there is an advantage that the dials 14a and 14b can be operated with the values of the dials 14a and 14b used last time without setting again when the dials 14a and 14b are used, and the operability is improved as compared with the prior art.

  Further, if the stored values set by the depression amounts of the plurality of accelerator pedals 15 can be executed, a plurality of basic set values can be set in accordance with the work system, and the operability is improved as compared with the prior art.

  A PTO dedicated switch 19 (see FIG. 2) is provided. While pressing the PTO dedicated switch 19, the highest speed setting dial 14a or the vehicle speed slow response dial 14b is used to reach the maximum speed or the vehicle speed slow response speed (reach the target PTO shaft speed). By setting the time until the operation time, a working machine such as a moor connected to the tractor (traveling vehicle) can be driven at the highest speed or the slow response speed of the vehicle, and the workability and versatility are improved.

  At this time, as shown in FIG. 7, the traveling system set values (maximum speed or time until the target rotational speed is reached) respectively set by the maximum speed setting dial 14a or the vehicle speed slow response dial 14b on the operation panel 9b. To be able to display.

  As described above, the maximum speed of the PTO shaft or the slow response speed of the vehicle (time until the target rotational speed of the PTO shaft is reached) can also be set using setting means such as the maximum speed of the traveling system. The number of switches installed can be reduced as compared with the prior art.

  Further, when the front wheel 2 is lifted from the ground while the tractor is traveling uphill, the control device 100 having a control configuration in which the set values of the maximum speed and the slow vehicle response speed are automatically reduced by about 30 to 40%. By adopting it, it is possible to ensure the safety while driving uphill. Here, the fact that the tractor is traveling on an uphill is detected by a longitudinal inclination sensor 26 attached to the traveling vehicle body 1.

  When setting the maximum speed or the vehicle speed slow response speed with the maximum speed setting dial 14a or the vehicle speed slow response dial 14b, the maximum speed setting dial 14a or the vehicle speed slow response dial 14b is set to the cut position K of each dial 14a, 14b. By preventing the engine 5 from starting unless it is in (shown in FIG. 6), the safety of the tractor can be maintained.

  This is because when the engine 5 is suddenly set to the maximum speed setting value or the vehicle speed slow response speed, it is dangerous and a heavy load is applied to the engine 5 at the time of starting the engine, and the durability of the engine 5 is impaired. is there.

  In addition to the maximum speed setting dial 14a and the vehicle speed slow response dial 14b, an engine speed dial 27 that can set the engine speed may be provided. In this case, it is not necessary to provide the throttle lever 11.

  If the engine speed cannot be increased when the maximum speed setting dial 14a or the vehicle speed slow response dial 14b is close to the maximum value during the initial movement of the tractor, there is no possibility that the tractor suddenly starts suddenly.

When the tractor is traveling at the maximum speed set with the maximum speed setting dial 14a, the vehicle speed slow response dial 14b cannot be set to ensure safety.
When the accelerator pedal 15 is locked, the accelerator pedal position sensor 15a detects that the accelerator pedal 15 does not return to the original position, so the control device 100 performs control to stop the engine 5 for safety.

  Control is performed so that the emergency stop of the tractor works when the operator leaves the cockpit 9 while the tractor is traveling on a cruise. Since the seat switch 32 is arranged in the cockpit 9, when the operator leaves the cockpit 9, the seat switch 32 is activated to stop the engine 5.

  Since the agility is lost when the tractor is about to stall during heavy load work such as a loader, the control apparatus 100 may be provided with a control configuration that keeps the setting at the vehicle speed slow response dial 14b more agile.

  Further, the collective off switch 20 may be provided, and the collective off switch 20 may be turned on so that the maximum speed setting dial 14a, the vehicle speed slow response dial 14b, and the auto cruise switch 14c cannot be set.

By turning on the batch off switch 20, it is safe because the dials 14a, 14b and the switch 14c are not operated even if they are mistakenly operated.
The forward / backward lever 10 is abolished and a dial 14x incorporating the forward / backward function of the tractor is provided at the position where the highest speed dial 14a is located, and “highest speed (forward) ← low speed ← N → low speed (reverse) → highest speed” If a large number of driving modes can be set by turning the dial 14x, the usability is improved.

  When the tractor slips due to road conditions, the control device 100 performs control to slightly lower the set value by the vehicle speed slow response dial 14b, so that safe driving can be maintained. Here, the slippage of the tractor can be recognized by a sudden drop in the detection value of the vehicle speed sensor 53.

  Further, during the turning of the tractor, control is performed so that the vehicle speed slow response dial 14b cannot be set for safety. Whether or not the tractor is turning can be determined by the steering sensor 28 provided on the operation shaft portion of the handle 7.

  Furthermore, the vehicle speed slow response dial 14b is set so that the tractor does not suddenly go down the hill when climbing while going uphill, and so that it does not fall suddenly while going up the hill. Regardless of the value, the control device 100 may be provided with a control configuration for performing control so that the vehicle speed slow response speed becomes more sensitive. At this time, the uphill can be easily detected by the longitudinal inclination sensor 26 of the vehicle body 1.

  Similarly, the vehicle speed slow response speed is made more sensitive to whatever value is set in the vehicle speed slow response dial 14b so that the slope does not fall while descending while going downhill. The control device 100 may be provided with a control configuration for performing control.

On the contrary, the control device 100 may be provided with a control configuration for controlling the vehicle speed slow response speed to be insensitive (weak) so that the speed does not suddenly increase while traveling downhill.
In order to eliminate the shock when the pedal is operated from forward to reverse when an accelerator (forward / reverse) pedal 15 is used instead of the forward / reverse lever 10 and the pedal 15 has a so-called one-pedal structure of forward / backward seesaw type. In addition, safety is ensured by providing the control device 100 with a control configuration that performs control that makes the vehicle speed slow response speed insensitive (weak) near neutral. Also in this case, it becomes insensitive (weak) whatever the set value of the vehicle speed slow response dial 14b. In this case, a one-pedal switch 15x is used instead of the depression type accelerator pedal 15.

  Further, when the attachment of the maximum speed setting dial 14a to the tractor is abolished, it is possible to adopt a control configuration in which the maximum speed is set when the accelerator pedal 15 is fully depressed when traveling is stopped (before traveling). In this case, the installation of the maximum speed setting dial 14a can be eliminated to reduce the cost.

  When the accelerator pedal 15 is held at a fixed position, it is possible to adopt a control configuration that enables automatic cruise traveling. For example, the vehicle travels a predetermined distance (for example, 10 m) by holding the accelerator pedal 15 at a fixed position. In such a case, for example, control is performed to travel at a speed when traveling 10 m. With this configuration, the installation of the auto cruise travel switch 14c can be omitted.

  Further, when the vehicle is traveling with a certain amount of time on the accelerator pedal 15, it is possible to have a control configuration that allows automatic cruise traveling. Also in this case, the installation of the auto-cruise travel switch 14c can be omitted.

  Furthermore, an auto-cruise memory may be provided, and when the auto-cruise switch 14c is pressed for a certain time, the auto-cruise setting is made and the vehicle can start running. In this way, it is possible to simplify the auto-cruise traveling setting.

  If the rotational speed of the PTO shaft 55 is increased as the accelerator pedal 15 is depressed, the rotational speed of the PTO shaft 55 can be controlled. With this control, for example, when lawn mowing work is performed with a tractor, the mowing can be effectively performed by increasing the vehicle speed, lowering the mower, and increasing the rotation speed of the cutter.

  When the auto-cruise switch 14c is turned on when the switch 14c is pulled up and turned off when the switch 14c is pushed down, safety can be ensured only by pressing the auto-cruise switch 14c when auto-cruise is set or when there is a malfunction.

If the configuration in which the operation of the auto-cruise switch 14c becomes effective only after the accelerator pedal 15 is depressed and travels for a certain time or a certain distance, the safety becomes higher than the conventional one.
Further, on the left side of the cockpit 9, an auxiliary transmission lever 21, a mid PTO transmission lever 23a, a rear PTO transmission lever 23b, and a 4WD lever 24 are arranged. An auxiliary transmission lever 21 is disposed outside the 4WD lever 24, and a mid PTO transmission lever 23a is disposed outside the rear PTO transmission lever 23b.

  In an emergency such as a valve stick, the HST trunnion shaft 30 can be forcibly returned to neutral by fully depressing the brake pedals 16 and 16 in the control section shown in FIG.

  In a tractor with HST servo, when the operating position of the throttle lever 11 detected by the throttle lever sensor 11a is in the vicinity of the half throttle position (when the engine speed is about half of the maximum speed), When it is determined that a load is placed in a bucket of a loader (not shown) that can be moved up and down, and the forward / reverse lever 10 is on the forward side (the rotation direction of the trunnion shaft 30 is forward) The throttle lever 11 is left as it is, and the engine speed is kept constant and the accelerator pedal 15 is depressed to increase the hydraulic output of the HST 34 to increase only the vehicle speed, but the forward / reverse lever 10 is on the reverse side. In this case, the rotation speed corresponds to the rotation angle of the trunnion shaft 30 corresponding to the depression amount of the accelerator pedal 15, and the die By varying in speed slower response speed slower than the speed change rate set by Le 14b, it may be performed gently raising control vehicle speed.

  Further, the turning angle of the trunnion shaft 30 is increased by depressing the accelerator pedal 15, and the engine speed is increased when the accelerator pedal 15 is further depressed even if the engine speed becomes equal to or higher than the half throttle. The vehicle speed is increased by increasing the operation amount of the trunnion hydraulic proportional valve 65 for adjusting the rotation angle of the trunnion shaft 30 controlled by the controller 100 according to the depression amount of the accelerator pedal 15.

  By controlling the engine speed as described above, fuel efficiency can be reduced in the half throttle state. In particular, when the vehicle is traveling backward, by gradually increasing the engine speed, the engine driving force can be reduced and fuel consumption can be reduced.

  Further, the arrival speed to the target speed can be changed according to the forward / reverse switching speed of the forward / reverse lever 10 detected by the forward / reverse lever sensor 10c provided at the base of the forward / reverse lever 10. For example, when the forward / reverse lever 10 is switched quickly in consideration of the operator's intention, the time to reach the target speed can be shortened.

  In addition, a control configuration that can change the speed to reach the target speed according to the forward / reverse switching speed of the forward / reverse lever 10 (considering the operator's intention according to the forward / backward switching speed of the forward / backward lever 10). In addition, when switching between forward and reverse quickly, the time to reach the target speed is shortened), and at this time, the switching speed from reverse to forward is higher than the switching speed from forward to reverse , Increase the time to reach the target speed. This is to prevent the operator from feeling afraid of switching from backward to forward.

  In the tractor with HST servo, the switching speed from reverse to forward is switched from reverse to reverse at the same time as control for changing the speed to reach the target speed in accordance with the forward / backward switching speed of the forward / reverse lever 10. By making it slower than the speed so that the speed to reach the target speed becomes slower, the fear of the operator is eliminated, and further, the detected value of the HST output shaft rotation sensor 35a and the detected value of the trunnion shaft rotation angle sensor 30a. (The difference between the two detected values from the predetermined value) is determined to determine the traction load of the work implement, and the output change speed of the hydrostatic continuously variable transmission 34 is adjusted according to the traction load. Thus, work such as loader work can be easily performed. For example, if it is determined that the load of the loader (not shown) is filled with earth and sand by judging the tractor's traction load, it will move back and forth more slowly than when there is no earth or sand so as not to drop the earth and sand from the loader bucket. Adopting a control configuration that switches between hexes.

This control configuration is also performed to prevent the operator from feeling afraid of switching from backward to forward.
If the difference between the detected values of the trunnion shaft rotation angle sensor 30a and the HST output shaft rotation sensor 35a deviates from a predetermined value, it is determined that the tractor has a traction load, and the feedback speed can be changed. .

  Normally, the trunnion shaft rotation angle and the HST output shaft rotation speed are proportional to each other. However, depending on the travel load, even if the trunnion shaft rotation angle is constant, the HST output shaft rotation speed changes when a load is applied. When the engine speed is constant, the change in the engine speed is read, and the change speed of the trunnion hydraulic proportional valve 65 is adjusted according to the amount of change per time. For example, if the change speed of the HST trunnion hydraulic proportional valve 65 (FIG. 4) is made slow, the vehicle speed can also be lowered slowly.

  In addition, when the traction load of the tractor is determined and the feedback speed is changed based on the deviation between the trunnion shaft rotation angle sensor 30a and the HST output shaft rotation sensor 35a, the traction load of the tractor is not changed. When the engine speed decreases, it is determined that there is a PTO load, and the vehicle speed is controlled to be reduced to prevent engine stall due to the PTO load.

  Further, since the traction load of the tractor is judged based on the deviation between the trunnion shaft rotation angle sensor 30a and the HST output shaft rotation sensor 35a, the traction load does not change and the throttle lever 11 is not operated. When there is no detection of the movement of the throttle lever 11 by 11a and the engine speed varies due to the PTO load, the change speed of the HST trunnion hydraulic proportional valve 65 is adjusted to lower the vehicle speed.

This is to prevent the engine stall when the engine drop occurs due to the PTO load during traveling at a constant vehicle speed during the PTO operation.
Further, the deviation of the trunnion shaft rotation angle sensor 30a and the HST output shaft rotation sensor 35a and the variation of the engine speed are comprehensively determined (detection values of the trunnion shaft rotation angle sensor 30a and the HST output shaft rotation sensor 35a). If the engine speed is low and the engine speed is low, it is determined that the load is large, and even if the detected values of the trunnion shaft rotation angle sensor 30a and the HST output shaft rotation sensor 35a are misaligned, If the number has not decreased, there may be a problem due to the structure of the mechanical member, not the load), and the change speed of the trunnion hydraulic proportional valve 65 is adjusted by sensing both the tractor traction load and the PTO load fluctuation. Thus, a control configuration for changing the vehicle speed may be adopted.

Thus, it is possible to prevent engine stall by detecting fluctuations in the PTO load and the traction load and reducing the vehicle speed in accordance with the load.
The output of the hydrostatic continuously variable transmission (HST) 34 is determined by the rotation angle of the trunnion shaft 30 and will not be described in detail, but according to the detection value of the accelerator pedal position sensor 15a as described above. The operation amount of the trunnion shaft 30 is automatically set by the control device 100 by the trunnion hydraulic proportional valve 65, and the hydraulic output of the hydrostatic continuously variable transmission (HST) 34 is automatically set to an appropriate value.

  It should be noted that the forward / reverse switching lever 10 is switched to the forward side or the reverse side, and the forward / reverse lever position sensor 10c (shown only in FIG. 5) provided at the rotating base of the forward / reverse switching lever 10 detects the forward movement. The control device 100 changes the turning direction of the trunnion shaft 30 of the hydrostatic continuously variable transmission (HST) 34 forward or backward by a method such as operation of the side solenoid 10a and the reverse solenoid 10b (shown only in FIG. 5). Set to the side. The turning direction of the trunnion shaft 30 is determined by the switching valve 63 (FIG. 4). Then, the rotation angle of the trunnion shaft 30 changes according to the depression amount of the accelerator pedal 15. The rotation angle of the trunnion shaft 30 is determined by the amount of current to the trunnion hydraulic proportional valve 65.

Further, in the event of an emergency such as a valve stick, the HST trunnion shaft 30 can be forcibly returned to neutral by fully depressing the brake pedal 16 in the control section.
As described above, the hydraulic output of the hydrostatic continuously variable transmission (HST) 34 is changed by the trunnion hydraulic proportional valve 65 according to the depression amount of the accelerator (HST) pedal 15, and the trunnion shaft 30 of the HST 34 is rotated. By changing the angle and changing the inclination angle of the swash plate 34d provided on the trunnion shaft 30 to change the output of the HST 34 steplessly, an accelerator pedal position sensor 15a for detecting the depression amount of the accelerator (HST) pedal 15 is detected. If there is an abnormality in the operation panel 9b, the presence of some abnormality in the accelerator (HST) pedal 15 on the operation panel 9b is displayed and output on the display screen with appropriate graphics, characters, voices, and the like.

  Further, when the value of the pedal position sensor 15a of the accelerator pedal 15 is out of the specified range during auto-cruise traveling, the control pedal 9 on the operation panel 9b is changed. It can be made fail-safe by performing a display output on the display screen with an appropriate figure, character, voice, etc., and canceling the auto-cruise control.

In the abnormal processing of the accelerator pedal position sensor 15a that regulates the output from the operation amount of the accelerator pedal 15 to the solenoid valve (solenoid) of the trunnion hydraulic proportional valve 65, when the sensor value is out of the prescribed range during auto cruise control, the accelerator pedal A display 15 indicates that there is any abnormality 15 on the operation panel 9b with appropriate graphics, characters, voices, etc., and turns off the auto cruise lamp.
DESCRIPTION OF SYMBOLS 1 Traveling vehicle body 2 Front wheel 3 Rear wheel 5 Engine 5a Engine rotation sensor 6 Handle post 7 Steering handle 8 Fuel tank 9 Pilot seat (seat) 9b Operation panel 10 Forward / reverse lever 10a Forward solenoid 10b Reverse solenoid 10c Forward / reverse lever position sensor 10d Forward / backward lever switching speed sensor 11 Throttle lever 11a Throttle lever sensors 12a, 12b Lever guide 13 Step floor 14a Maximum speed restriction dial 14b Vehicle speed slow response dial 14c Auto cruise switch 15 Accelerator pedal 15a Accelerator pedal position sensor 16 Brake pedal 17 Memory 1 Switch 18 Memory 2 switch 19 PTO dedicated switch 20 Collective off switch 21 Sub-transmission lever 21a Sub-transmission lever position sensor 22 Bonnet 23 Mid PTO speed change lever 23b Rear PTO speed change lever 24 4WD lever 26 Car body longitudinal tilt sensor 27 Engine rotation dial 28 Steering sensor 30 Trunnion shaft 30a Trunnion shaft angle sensor 31 Link 32 Seat switch 33 HST input shaft 34 Hydrostatic continuously variable transmission (HST) 34a Hydraulic pump 34b Hydraulic motor 34c Hydraulic closed circuit 34d Swash plate 35 Traveling output shaft 35a HST output shaft rotation sensor 36 Rotating shaft 38 Engagement type transmission 39 Sub transmission clutch shifter 43 Transmission shaft 46 Differential device 47, 57, 58 , 59 Gear 48 Front wheel output shaft (4WD shaft)
51 pump output shaft 52 PTO shaft 53 rotational speed sensor (vehicle speed sensor) 54 hydraulic clutch 55 rear PTO shaft 56 mid PTO shaft 63 switching valve 65 trunnion hydraulic proportional valve 77a left brake switch 77b left brake switch 90 memory 100 controller

Claims (3)

An engine (5) mounted on the traveling vehicle body (1);
Engine speed detecting means (5a) for detecting the speed of the engine (5);
The motive power of the engine (5) is input, and the hydraulic pump (34a) is operated to change the inclination angle of the trunnion shaft (30) having the swash plate (34d) and the inclination angle of the swash plate (34d). A hydrostatic transmission (34) for driving the travel output shaft (35) by output;
A gear-engaged, multiple-stage sub-transmission (38) that receives the rotational power of the hydraulic continuously variable transmission (34) and changes gears;
Traveling wheels (2 and / or 3) driven by the output of the auxiliary transmission (38);
Auxiliary transmission operating means (21) for operating the auxiliary transmission by the auxiliary transmission device (38) to the low speed side and the high speed side;
A forward / reverse lever (10) for switching the forward or reverse rotation of the traveling wheels (2 and / or 3) according to the forward or reverse rotation angle of the trunnion shaft (30) and the forward / reverse lever ( The output amount of the hydrostatic transmission (34) is changed by changing the rotation angle of the trunnion shaft (30) corresponding to the combination of the forward / reverse lever position sensor (10c) for detecting the operation position of 10) or the amount of depression. A combination of an accelerator pedal (15) to be changed and an accelerator pedal detection means (15a) for detecting the depression amount of the accelerator pedal (15);
A maximum speed setting dial (14a) for regulating the maximum speed of the vehicle body (1) by adjusting the rotation angle of the trunnion shaft (30) of the hydraulic continuously variable transmission (34);
A vehicle speed slow response dial (14b) for setting the rotation angle of the trunnion shaft (30) of the hydraulic continuously variable transmission (34) to a vehicle speed slow response speed;
A control device (100) having a memory (90) for storing setting positions of the maximum speed setting dial (14a) and the vehicle speed slow response dial (14b) ;
A working machine is connected to the traveling vehicle body (1), and a PTO shaft (55 or 56) for transmitting engine power to the working machine is provided on the lower side of the auxiliary transmission (38).
A PTO dedicated switch (19) that can set the rotational speed of the PTO shaft (55 or 56) by the maximum speed setting dial (14a) and the vehicle speed slow response dial (14b);
When the PTO dedicated switch (19) is input, the control device (100) has a control configuration in which the operation of the work implement corresponds to the set value of the maximum speed setting dial (14a) or the set value of the vehicle speed slow response dial (14b). A work vehicle characterized by being provided. 2. The work vehicle according to claim 1, wherein the memory (90) is configured to be capable of storing a plurality of set values of a maximum speed setting dial (14 a) and a set value of a vehicle speed slow response dial (14 b). When the traveling vehicle body (1) is provided with a front / rear inclination sensor (26) of the traveling vehicle body (1), the front / rear inclination sensor (26) detects the inclination when the preset front wheel (2) is lifted from the ground. claim, characterized in that provided on the high speed setting dial (14a) and the control device control configuration is reduced by the value set the engine speed respectively set in advance by the vehicle speed slow response dial (14b) (100) 1 or 2 The work vehicle as described in.

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