JP6102838B2 - Work vehicle - Google Patents

Description

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

  2. Description of the Related Art Conventionally, a work vehicle is driven at a constant speed by using an automatic cruise control device (a constant speed travel control device) including a hydraulic continuously variable transmission (HST) or a hydraulic-mechanical continuously variable transmission (HMT). There are known ones that can perform auto-cruising. By maintaining the traveling speed constant, it is possible to improve fuel efficiency and work for a long time.

  The constant speed traveling control device is configured to operate a speed setting lever (or a speed setting switch, etc.) to maintain the speed when a desired traveling speed is reached by operating an accelerator pedal (shift pedal), and a brake pedal. Alternatively, when the clutch pedal is operated, the constant speed traveling control is canceled.

  However, in the case of agricultural work, for example, plowing work, planting work, cutting work, etc., when turning at the end of the field, supplementing seedlings while going straight, or interrupting work due to obstacles, etc. Since the constant speed running control is canceled, when the work is resumed, the set speed does not match the previous time, and the speed may change slightly.

  Therefore, in Patent Document 1 below, a speed change lever, a clutch pedal, and a speed setting lever are connected to a rotation arm of a transmission shaft of the HST by a link mechanism, and a speed setting lever is provided between the rotation arm and the speed setting lever. A configuration is disclosed in which a mechanism that allows and reproduces the operation of the clutch pedal within the range of the set speed held in the above is disclosed. With this configuration, even if the clutch pedal is depressed during auto-cruise driving and the vehicle is stopped, the setting position of the speed setting lever is maintained. Can be reproduced.

JP 2007-224985 A

  With the configuration described in Patent Document 1, since the constant speed is automatically reproduced, there is no need to set the constant speed every time the clutch pedal is depressed. On the other hand, depending on the working conditions and the state of the field, it may be desired to temporarily increase or decrease the speed of the auto cruise traveling. There are also cases where it is desired to change the speed during auto-cruise driving.

  In such a case, the constant speed running control is canceled by operating the brake pedal or the clutch pedal, and when the shift pedal is returned, the vehicle decelerates, and when the shift pedal is depressed, the speed increases. Since the speed adjustment is subtle and difficult, it becomes a burden for an unfamiliar worker, resulting in poor operability and running performance.

  Therefore, the problem of the present invention is that it is not a burden on the operator when it is desired to change the speed temporarily during auto-cruise traveling or to change to a desired speed, and the speed can be changed with a simple and easy operation. It is to provide a work vehicle with improved traveling performance.

The above-described problems of the present invention are solved by the following solution means.
According to the first aspect of the present invention, there is provided an engine (5) mounted on a traveling vehicle body (1), and an inclination of a swash plate (34d) for adjusting the hydraulic pressure to be input and output from the engine (5). A hydrostatic continuously variable transmission (34) having a trunnion shaft (30) for changing an angle and outputting an output rotational speed based on a hydraulic pressure corresponding to a rotation angle of the trunnion shaft (30), and the trunnion shaft A trunnion shaft rotation mechanism (34a, 65, etc.) for rotating (30), a sub-transmission (38) that receives a rotational force from the hydrostatic continuously variable transmission (34), and The travel device (2 and / or 3) driven by the output of the auxiliary transmission (38), and the rotation angle of the trunnion shaft (30) corresponding to the depression amount, the trunnion shaft rotation mechanism (34a, 65, etc.) ) Accelerator pedal (15 And an accelerator pedal detecting means (15a) for detecting the depression amount of the accelerator pedal (15), and an operating means for auto cruise traveling (14c) for keeping the traveling speed of the traveling device (2 and / or 3) constant. ), And a speed increasing switch (101) or a speed reducing switch (102) for speeding up or decelerating during constant speed traveling by the auto cruise traveling operating means (14c), which is turned on only while being pressed. When the auto-cruise driving operation means (14c) is operated, the trunnion shaft (30) rotates corresponding to the depression amount of the accelerator pedal (15) detected by the accelerator pedal detection means (15a) at that time. The traveling speed of the traveling device (2 and / or 3) is controlled by controlling the trunnion shaft rotation mechanism (34a, 65, etc.) so as to maintain the angle. An auto-cruise function that keeps constant, and when the acceleration switch (101) or the deceleration switch (102) is pressed within a predetermined time during the auto-cruise function, the trunnion shaft turning mechanism (34a, 65, etc.) is controlled. A temporary acceleration / deceleration function for temporarily increasing or decelerating the running speed for the predetermined time, and the acceleration switch (101) or the deceleration switch (102) during the auto-cruise function reduces the predetermined time. When the pushing operation is performed beyond the above, while the pushing operation is being performed, the trunnion shaft turning mechanism (34a, 65, etc.) is controlled to continuously increase or decrease the traveling speed at that time. it is a work vehicle equipped with a control device and (100) and a speed reduction function.

According to a second aspect of the present invention, the control device (100) cancels the operation after the acceleration switch (101) or the deceleration switch (102) is pushed beyond the predetermined time during the auto-cruise function. Once a working vehicle according to claim 1, further comprising an auto cruise speed change function to keep the running speed at the time of the release by controlling the trunnion axis rotation mechanism (34a, 65, etc.) to be constant.

  According to the first aspect of the present invention, when it is desired to change the speed temporarily during auto-cruise traveling, the speed change switch (101) or the speed reduction switch (102) is temporarily pushed by a simple operation. Speed can be changed, and operability and running performance are improved without burdening unskilled workers.

Moreover , the speed at the time of auto-cruise traveling can be easily increased or decreased to a desired speed by long-pressing the acceleration switch (101) or the deceleration switch (102). Accordingly, versatile usage is possible, and operability and running performance are further improved.

According to the invention described in claim 2 , in addition to the effect described in claim 1 , the speed at the time of auto-cruise traveling can be changed to a desired speed by a simple and easy operation.

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 the figure which showed the relationship between the depression amount of an accelerator pedal, and a vehicle speed.

  An embodiment 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 is an overall side view, and FIG. 2 is a plan view of the tractor of FIG. 3 is a power transmission mechanism diagram of the transmission system of the tractor of FIG. 1, FIG. 4 is a hydraulic circuit diagram of the hydrostatic continuously variable transmission system of the tractor of the present embodiment, and FIG. 5 is a control of the tractor of the present 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 (FIG. 3) mounted on the front portion of the vehicle body 1 is transmitted in the transmission case. The transmission is appropriately decelerated by the transmission and is transmitted to the front wheels 2 and 2 and the rear wheels 3 and 3. The engine speed (rpm) is detected by an engine speed sensor 5a (FIG. 5). The engine speed sensor 5 a detects the rotation of the crankshaft of the engine 5, and the position of the engine speed sensor 5 a varies depending on the type of the engine 5.

  A steering handle 7 is supported on the handle post 6 at the center of the vehicle body 1, and a cockpit 9 is provided behind the steering handle 7. Further, 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, but can be used for both traveling on the road and working.

The engine speed increases in accordance with 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) provided at the base of the accelerator pedal 15, and this accelerator pedal position sensor 15a. 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. The rotation angle of the trunnion shaft 30 is detected by a trunnion shaft angle sensor 30a (FIG. 5).
In this embodiment, as shown in FIG. 4, the trunnion shaft 30 is rotated by a hydraulic motor, but the trunnion shaft 30 may be rotated by an electric motor. Then, the output of the HST 34 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.

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 controller (controller) 100 advances the turning direction of the trunnion shaft 30 of the hydrostatic continuously variable transmission (HST) 34 by a method such as operation of the side solenoid 10a and the reverse solenoid 10b (shown only in FIG. 5). Set to side or 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 changed by the current value to the proportional solenoid of the trunnion hydraulic proportional valve 65. These trunnion hydraulic proportional valve 65, constituting the trunnion shaft rotation mechanism by the switching valve 63 and the hydraulic pump 3 4 a (FIG. 4) or the like.

  The throttle lever 11 is used to change the engine speed and is used during work travel. The operation position of the throttle lever 11 is detected by a throttle lever sensor 11 a provided at the base of the throttle lever 11. 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.

  FIG. 4 shows the case where the swash plate 34e is provided also on the motor 34b side (variable motor), but generally there is no swash plate on the hydraulic motor 34b side, and it is a fixed quantity motor. As shown in FIG. 4, as a configuration capable of controlling the movement of the swash plate 34e, for example, when changing the running speed of the vehicle by changing the rotation angle of the swash plate 34e, the torque is changed to a high speed or a low speed. It is good also as a structure which can be selected with the switching lever which is not shown in figure (variable hydraulic motor).

  In the case of a variable hydraulic motor, during auto-cruise traveling, which will be described later, it is desired to maintain the speed at that time, so the swash plate 34e on the motor 34b side is held by not operating the switching lever. Since operating the switching lever means changing the speed, it is better to cancel the auto-cruise function.

  As shown in FIG. 3, the gear-type transmission 38 is shifted by the sub-transmission clutch shifter 39 and is shifted into three stages of low speed, medium speed, and high speed. The power shifted to the three speeds is transmitted from the transmission shaft 43 to the rear wheel 3 via the differential device 46. The operation position of the auxiliary transmission lever 21 is detected by an auxiliary transmission lever position sensor 21 a provided at the base of the auxiliary transmission lever 21.

  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 transmitted to the rear wheel 3 via the differential device 46, and the rear wheel 3 is driven at the traveling speed of the sub-speed 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. Is decided. Although detailed description is omitted, when the depression amount of the accelerator pedal 15 is detected by the accelerator pedal position sensor 15a, the current value to the proportional solenoid of the trunnion hydraulic proportional valve 65 is determined according to the detected value of the accelerator pedal position sensor 15a. The hydraulic output of the hydrostatic continuously variable transmission (HST) 34 is automatically set to an appropriate value by being controlled by the control device 100 and automatically setting the operation amount (rotation speed) of the trunnion shaft 30. Is done.

  Further, in an emergency, the HST trunnion shaft 30 can be forcibly returned to the neutral position by fully depressing the brake pedals 16 and 16 in the control section. When the brakes 16 and 16 are stepped on, the operator (driver) keeps his or her foot off 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. . When the accelerator pedal 15 is returned during traveling, the vehicle begins to decelerate without stepping on the brake 16, but when the vehicle does not decelerate, such an operation can be performed by clearly recognizing an abnormality.

FIG. 5 shows a control block diagram of the tractor control apparatus 100 of the present embodiment.
As shown in the overall plan view of the tractor shown in FIG. 2, a throttle lever 11 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.

  Furthermore, the lever guide 12a of the lever 12 for raising and lowering the work implement on the right side of the cockpit 9 (FIG. 6) includes a maximum speed setting dial 14a, a vehicle speed slow response dial 14b, and a cruise travel switch 14c in a line from the front side to the rear side. Has been placed. 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 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 set to the insensitive side (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 (referred to as vehicle speed slow response speed) is slow. Therefore, it is a structure that accelerates slowly. 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. When the cruise travel switch 14c is turned on while traveling at a specific speed, the cruise travel switch 14c automatically switches to a constant speed (auto cruise function), and the accelerator pedal. Even if the foot is released from 15 (although the accelerator pedal 15 returns to the position before being depressed), the speed at that time is maintained (auto-cruise traveling). Note that when the brake pedal 16 is depressed, the auto-cruise traveling is canceled. Further, even if the cruise travel switch 14c is turned off, the automatic cruise travel is canceled.

  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. A vehicle speed sensor 53 (FIG. 5) for detecting the vehicle speed is attached to a mission case (not shown), and is configured to pick up the rotational speed of the shaft that can detect the vehicle speed.

  Since these dials 14a and 14b and the switch 14c are arranged in a line in the front-rear direction at a position adjacent to the cockpit 9, there is no hesitation in selecting the dials 14a and 14b and the switch 14c. I can put it 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 set value of the maximum speed setting dial 14a and the set value of the vehicle speed slow response dial 14b can be stored in the memory 90 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 90 at the next use.

  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. A short press is an operation of pressing and releasing immediately, and a long press is an operation of continuing to press for a certain time. This determination is based on the time measured by the timer 92 of the control device 100 (an on / off input signal from the switch).

  Thus, in 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 the maximum speed again when the dials 14a and 14b are used, and the operability is improved over 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.

  Furthermore, the current depression amount of the accelerator pedal 15 can be stored by long pressing the memory 2 switch 18. 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.

  As described above, in the tractor according to the present embodiment, even when the cruise travel switch 14c is turned on, the auto cruise travel is performed even if the foot is released from the accelerator pedal 15. However, depending on the working conditions and the state of the field, the auto cruise travel is temporarily performed. There is a case where it is desired to increase or decrease the speed. When the brake pedal 16 is stepped on, the auto-cruise traveling is canceled and the traveling state according to the positions of the forward / reverse switching lever 10 and the accelerator pedal 15 is established. That is, when the accelerator pedal 15 is returned or the brake pedal 16 is depressed, the speed is reduced, and when the accelerator pedal 15 is depressed or the maximum speed setting dial 14a is set to the maximum value (max), the speed is increased. In addition, since the speed increase / decrease operation is delicate and difficult, it may be a burden for an unfamiliar worker and may be inferior in operability and running performance.

  Therefore, in the tractor of the present embodiment, an acceleration switch 101 and a deceleration switch 102 (buttons, etc.) that can temporarily accelerate or decelerate during auto-cruise traveling are provided below the cruise traveling switch 14c. The acceleration switch 101 and the deceleration switch 102 are turned on only while being pressed. When the acceleration switch 101 or the deceleration switch 102 is pressed and released immediately during auto-cruise traveling (short press), only the moment of pressing. The speed is slightly increased or decreased from the speed at that time.

  When the acceleration switch 101 and the deceleration switch 102 are pressed, the trunnion shaft 30 rotates. Depending on how much acceleration the trunnion shaft 30 is changed, how many kilometers per hour is increased or decreased with respect to the current speed. Determined. As the method, there is a method of interlocking with the vehicle speed slow response dial 14b or the like.

  For example, this acceleration is set to an appropriate value according to the dial values of the maximum speed setting dial 14a and the vehicle speed slow response dial 14b, and is large when the maximum speed setting dial 14a is maximum and the vehicle speed slow response dial 14b is maximum (sensitive). When the maximum speed setting dial 14a is the minimum and the vehicle speed slow response dial 14b is the minimum (insensitive), it is made small (that is, the lower limit).

  The acceleration range may be different depending on the type of work vehicle (type of work implement) such as 2 to 5 km / h or 5 to 10 km / h. Further, it may be different depending on the weight of the airframe (fuel amount, etc.). Even if the weight of the aircraft is different, the target value may be reached within the same fixed time. The acceleration can be easily understood by allowing the display unit 125 (FIG. 5) to be notified to the operator by a numerical value or a figure. The short press time is measured by the timer 92 for the switch input signal.

  That is, when the speed increasing switch 101 or the speed reducing switch 102 is pressed for a short time within a predetermined time, the speed is temporarily increased or decreased, but when the finger is released, the speed returns to the speed before the speed increasing or speed decreasing (temporary speed increasing / decelerating speed). function). The pushing time of the one-push of the speed increasing switch 101 or the speed reducing switch 102 is measured by the timer 92 of the control device 100 using an electrical signal (ON / OFF input signal) from the switch.

When an input signal of the speed increasing switch 101 or the speed reducing switch 102 (signal of the speed increasing switch sensor 101a or the speed reducing switch sensor 102a ) is input to the control device 100, an electric signal from the control device 100 is sent to the proportional solenoid of the trunnion hydraulic proportional valve 65. By outputting, the rotation angle of the trunnion shaft 30 is changed, and the inclination angle of the swash plate 34d is also changed to change the vehicle speed.

  As described above, when the acceleration switch 101 or the deceleration switch 102 is pressed for a short time, the vehicle speed slightly increases or decreases only at the moment the button is pressed, and when the finger is released, the original speed at the time of auto-cruise traveling (vehicle speed before the switch is pressed). Return to. Therefore, when it is desired to temporarily increase or decrease the speed, it can be performed by a single operation, which is very effective. For example, when a road cleaner is attached as a working machine and traveling on a road, it is convenient because it may be desired to increase or decrease the speed due to a traffic light or the like.

  With this configuration, when it is desired to change the speed temporarily during auto-cruise driving, the brake pedal 16 is depressed and sudden braking is not performed, and the accelerator pedal 15 is depressed and acceleration is not accelerated. Or you can slow down. Then, the speed can be temporarily changed by a simple and easy operation of pressing the speed increasing switch 101 or the speed reducing switch 102 only once, and the operability and running performance are improved without burdening unskilled workers. It is also convenient for beginners.

  As shown in FIG. 6, the acceleration switch 101 is indicated by an arrow pointing forward and the deceleration switch 102 is indicated by an arrow pointing backward, so that it is easy for the operator to distinguish between acceleration and deceleration. It is easy to operate and easy to operate. Even with a tractor traveling at high speed, the vehicle speed can be easily reduced.

  On the other hand, when the acceleration switch 101 or the deceleration switch 102 is pressed for a long time beyond the predetermined time, the speed is increased at a predetermined acceleration or decelerated at a predetermined deceleration while the button is being pressed (continuous). Acceleration / deceleration function). That is, when the acceleration switch 101 or the deceleration switch 102 is pressed, first, the acceleration or deceleration is the same as that of the previous short press, but thereafter the acceleration or deceleration is continuously increased. Although this acceleration varies depending on the acceleration of the trunnion shaft 30, for example, it is desirable that the acceleration can be changed in common with the vehicle speed slow response dial 14b as in the case of the short press. And it accelerates as it is with the same acceleration (equal acceleration) as the time of the previous short press. Alternatively, the acceleration may be increased by accelerating slowly for the first few seconds and holding it down. In addition, these may be switched by a switch operation or the like even while traveling.

  Therefore, the speed during auto-cruise traveling can be easily increased or decreased to a desired speed, so that it can be used with versatility, and operability and traveling performance are further improved. For example, there is a case where it is desired to accelerate sufficiently on an obvious straight road and a case where it is desired to sufficiently decelerate on an obvious curve.

  Also, by pressing the acceleration switch 101 or the deceleration switch 102 for a short time or a long time, different usages are possible, so that one switch can be used properly, which is convenient and reduces the number of parts.

  When the finger is released after long-pressing the acceleration switch 101 or the deceleration switch 102, the auto-cruise speed is changed to the speed at that time (the speed when the finger is released) (auto-cruise speed changing function). Accordingly, the speed during auto-cruise traveling can be changed to a desired speed with a simple and easy operation. As described above, these vehicle speeds are changed by outputting an electrical signal from the control device 100 to the proportional solenoid of the trunnion hydraulic proportional valve 65 in response to an input signal from the speed increasing switch 101 or the speed reducing switch 102. Is called.

  Even if the speed after pressing and holding the acceleration switch 101 or the deceleration switch 102 is felt slightly faster or slower, the speed can be easily changed by pressing and holding the acceleration switch 101 or the deceleration switch 102 again. It is very convenient.

  Further, the control device 100 outputs an electrical signal to the proportional solenoid of the engine electronic governor 103 (FIG. 5) and the trunnion hydraulic proportional valve 65 according to the depression amount of the accelerator pedal 15, thereby increasing the engine speed and the vehicle speed. However, the operator may want to manually change the engine speed by means of the throttle lever 11 independently of the accelerator pedal 15.

Therefore, an interlocking off switch 105 may be provided below the lever guide 12a so that the engine speed does not increase in conjunction with depression of the accelerator pedal 15.
When the interlocking off switch 105 is pressed (on), the signal of the interlocking off switch sensor 105a is input to the control device 100. At this time, even if the accelerator pedal 15 is depressed, no electrical signal is output from the control device 100 to the engine electronic governor 103. Accordingly, although the vehicle speed of the tractor increases, the operator can change the engine speed to a desired speed by the throttle lever 11. For example, when the accelerator pedal 15 is depressed by raising the engine speed to the maximum with the throttle lever 11 in advance, even when the same speed as that when the interlocking off switch 105 is turned off can be driven with a strong torque until the desired speed is reached. The time is shortened.

  As described above, even with a tractor in which the engine speed is interlocked with the depression of the accelerator pedal 15, by providing the interlock off switch 105, the engine speed can be independently changed by the throttle lever 11, and the usability is improved. .

  As described above, the tractor of the present embodiment is provided with the maximum speed setting dial 14a, and 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. Yes. FIG. 7 shows the relationship between the depression amount of the accelerator pedal and the vehicle speed when the maximum speed is set by the maximum speed setting dial 14a.

  When the maximum speed setting dial 14a is set to the maximum value (max) (straight line A) and when the minimum value (min) is set (straight line B), a speed difference C occurs when the accelerator pedal 15 is fully depressed. By setting the maximum speed with the maximum speed setting dial 14a, even if the accelerator pedal 15 is fully depressed, the speed does not become higher than that, so that the safety of the tractor can be maintained.

  However, the accelerator pedal 15 may be accidentally stepped on during maintenance such as when the tractor is stopped. In this case, the tractor moves, which is not preferable in terms of safety. Furthermore, if the maximum speed relatively close to max is set by the maximum speed setting dial 14a, it may be considered that the vehicle accelerates rapidly.

Here, when the operator turns the maximum speed setting dial 14a to the cutting position K, the vehicle speed of the tractor becomes zero.
That is, when the maximum speed setting dial 14a is at the cutting position K, the tractor does not travel even when the accelerator pedal 15 is depressed. Therefore, even if the accelerator pedal 15 is inadvertently depressed during maintenance or the like, the vehicle does not start, so it is safe.

  Note that a switch different from the maximum speed setting dial 14a may be provided and the vehicle speed may be shifted to zero by turning this switch on (turned off). With this configuration, the maximum speed setting dial 14a can be switched on and off, so that the operator can determine the intention of traveling (whether to travel or stop), and the safety of the worker is improved.

In addition, a maximum speed holding switch 110 that can hold the operation position of the maximum speed setting dial 14a is provided so that the setting value by the maximum speed setting dial 14a can be held. High speed is maintained, that is, it may not be changed even if the maximum speed setting dial 14a is operated again. When the maximum speed holding switch 110 is pressed (entered), a signal from the highest speed holding switch sensor 110a is input to the control device 100, and the control device 100 holds the highest speed set value at that time.

  Since the maximum speed setting dial 14a is a dial type, it is easy to be changed by an erroneous operation. However, according to this configuration, even if the maximum speed setting dial 14a is erroneously operated, the set value is retained, so that safety is improved. When the highest speed holding switch 110 is turned on and then pressed again, the highest speed holding switch 110 is turned off and the highest speed setting dial 14a is activated. That is, it becomes the regulation speed set by the maximum speed setting dial 14a. Therefore, the setting value can be held and released by the highest speed setting dial 14a simply and easily by only turning on and off the highest speed holding switch 110.

  As described above, the maximum speed setting dial 14a and the vehicle speed slow response dial 14b can be stored simultaneously by long-pressing the memory 1 switch 17, but the maximum speed setting switch 110 allows the maximum speed setting dial Only dial 14a is supported. The relationship between the memory 1 switch 17 and the fastest holding switch 110 will be described later.

  Further, by setting the vehicle speed slow response dial 14b to the cut position K, the function of the vehicle speed slow response dial 14b can be turned off. As described above, the vehicle speed slow response dial 14b is for making the arrival time to the target rotation angle of the trunnion shaft 30 constant regardless of how the accelerator pedal 15 is depressed. If 14b is set, it will accelerate according to the set value.

  However, depending on the work conditions and the worker, there is a case where it is desired to work without being limited by the arrival time (vehicle speed slow response speed) set by the vehicle speed slow response dial 14b. For example, even if the vehicle speed slow response dial 14b is set to the insensitive side, there is a case where it is desired to accelerate rapidly in the situation of an intersection signal.

Thus, by switching off the function of the slow response speed dial 14b, the acceleration state can be changed according to the situation by the operator.
That is, when the vehicle speed slow response dial 14b is turned off, the arrival time to the target rotation angle of the trunnion shaft 30 is changed according to how the operator depresses the accelerator pedal 15. For example, by depressing the accelerator pedal 15 at once, quick acceleration is possible.

  Note that a switch different from the vehicle speed slow response dial 14b may be provided, and turning on this switch may turn off the function of the vehicle speed slow response dial 14b. In this case, when the vehicle speed slow response dial 14b is turned off, it is safer to fix at a middle level between insensitivity and sensitivity.

Further, a vehicle speed slow holding switch 113 that can hold the operation position of the vehicle speed slow response dial 14b is provided so that the set value by the vehicle speed slow response dial 14b can be held, and the set value is held only by turning on the switch 113. That is, even if the vehicle speed slow response dial 14b is operated again, it may not be changed. When the vehicle speed slowness holding switch 113 is pressed (entered), a signal from the vehicle speed slowness holding switch sensor 113a is input to the control device 100, and the control device 100 holds the set value at that time.

  Since the vehicle speed slow response dial 14b is a dial type, it is easily changed by an erroneous operation. However, according to this configuration, the set position is maintained even if the vehicle speed slow response dial 14b is erroneously operated, so that safety is improved. When the vehicle speed slowness holding switch 113 is turned on and then pressed again, the vehicle speed slow response dial 14b is turned on. That is, the vehicle speed slow response speed set by the vehicle speed slow response dial 14b is obtained. Therefore, the setting value can be held and released by the vehicle speed slow response dial 14b simply and easily by only turning on and off the vehicle speed slow holding switch 113.

  As described above, the maximum speed setting dial 14a and the vehicle speed slow response dial 14b can be stored simultaneously by long-pressing the memory 1 switch 17, but the vehicle speed slow response switch 113 allows the vehicle speed slow response to be stored. It corresponds only to the dial 14b.

  The relationship among the memory 1 switch 17, the highest speed holding switch 110, and the vehicle speed slow holding switch 113 has various patterns depending on changes in the software of the control device 100. For example, there are the following control methods.

  First, when the memory 1 switch 17 is pressed and stored, the stored value stored in the fastest speed holding switch 110 and the vehicle speed slowness holding switch 113 disappears. When the memory 1 switch 17 is pressed for a short time, the stored value of the memory 1 switch 17 is reproduced, and when the memory 1 switch 17 is not pressed for a short time, the values of the maximum speed setting dial 14a and the vehicle speed slow response dial 14b are executed.

  Second, when the memory 1 switch 17 is pressed and stored, the stored values stored in the fastest holding switch 110 and the slow vehicle holding switch 113 are not erased. When the memory 1 switch 17 is pressed for a short time, the stored value of the memory 1 switch 17 is reproduced, and when the memory 1 switch 17 is not pressed for a short time, the values stored in the maximum speed holding switch 110 and the vehicle speed slow holding switch 113 are executed. Is done.

  Third, when the memory 1 switch 17 is pressed and stored, the stored values stored in the fastest holding switch 110 and the slow vehicle holding switch 113 are not erased. When the memory 1 switch 17 is pressed for a short time, the stored value of the memory 1 switch 17 is reproduced, and when the memory 1 switch 17 is not pressed for a short time, the values stored in the maximum speed holding switch 110 and the vehicle speed slow holding switch 113 are executed. However, the difference from the second method is that a short press of the maximum speed holding switch 110 and the vehicle speed slow holding switch 113 is a condition. When the maximum speed holding switch 110 and the vehicle speed slow holding switch 113 are not pressed shortly, the values of the maximum speed setting dial 14a and the vehicle speed slow response dial 14b are executed.

  The maximum speed holding switch 110 and the vehicle speed slow holding switch 113 also function as lamps (lights when on, turns off when off), and can be stored once by the fastest speed holding switch 110 or vehicle speed slow holding switch 113 (the lamp lights up). ) When the stored value is cleared by long-pressing the memory 1 switch 17 as in the first method, the lamp goes off (turns off), or the fastest holding switch 110 as in the third method. If it is executed when the vehicle speed slow holding switch 113 is pressed for a short time, it can be easily understood by the operator by making it blink.

Further, when the vehicle speed slow response dial 14b is set to the sensitive side to increase the sensitivity, if the accelerator pedal 15 is depressed at a stretch, the acceleration is suddenly accelerated. Therefore, when the time until the vehicle speed slow response dial 14b reaches a predetermined vehicle speed is short, the control device 100 may be configured to turn on the lamp 120. For example, the lamp 120 is turned on when the vehicle speed slow response dial 14b is set for about 3 seconds. Examples of the lamp 120 include a tail lamp and a brake lamp.
With this configuration, safety can be improved because the danger is recognized by a person around the tractor during work.

  In addition, a front sensor (such as an ultrasonic sensor) 123 that detects a front obstacle is provided at the front portion of the traveling vehicle body 1 of the tractor of the present embodiment, and the front sensor 123 is a front obstacle such as an oncoming vehicle during auto-cruise traveling. It is preferable that the control device 100 displays a warning on the display unit 125 (FIG. 5) of the operation panel 9b (FIG. 2). The warning display only needs to be visually recognized, and may be displayed on the display unit 125 with characters or graphics, the display unit 125 may be brightened, or the color of the display unit 125 may be changed. Further, a warning lamp (not shown) may be provided on the operation panel 9b so that the lamp is turned on.

  During auto-cruise traveling, the operator is often relaxed by removing his / her foot from the accelerator pedal 15, but this configuration makes it easier for the operator to notice obstacles ahead. Will improve.

  Note that this warning is not a means of visually recognizing that it is displayed on the display unit 125 or the like, but may be configured such that a sound flows or a buzzer 127 sounds so that it can be recognized by hearing. These means may be used in combination. By using a means that can be recognized visually and a means that can be recognized by hearing, safety is further improved.

  Further, when an obstacle such as a forward oncoming vehicle approaches slower than the vehicle speed of the tractor during auto-cruise traveling based on a detection value from the front sensor 123, the tractor may be gently stopped. When the front sensor 123 is an ultrasonic sensor, a change in the distance to the oncoming vehicle can be detected directly, so that the speed of the obstacle is calculated in consideration of the speed of the tractor.

  When the speed of the obstacle is slower than that of the tractor, it is safer to stop the tractor by gently returning the trunnion shaft 30 to the neutral position rather than stopping it suddenly. The time taken to stop in this case is adjusted to an appropriate time according to the vehicle speed of the tractor and the speed of the obstacle. When the oncoming vehicle is slower than the speed of the tractor, the tractor decelerates slowly.

  On the other hand, when the obstacle ahead is approaching faster than the vehicle speed of the tractor, it is better to stop the tractor quickly. In this case, the danger of a collision is prevented and safety is improved by emergency stopping the tractor. Therefore, when the oncoming vehicle is faster than the speed of the tractor, the tractor decelerates earlier.

  Moreover, when there is an obstacle ahead, you may comprise so that auto-cruise traveling cannot be performed immediately. That is, when the front sensor 123 senses an obstacle ahead, even if the cruise travel switch 14c is turned on at the time of departure, the vehicle does not shift to auto cruise travel. Therefore, the operator must operate the accelerator pedal 15 to adjust the vehicle speed.

  Since the worker is often relaxed by removing his / her foot from the accelerator pedal 15 during the auto-cruise traveling, the configuration improves the safety by maintaining the operator's tension state.

  Further, a seat switch (sensor) 32 is provided in the cockpit 9 and when the operator leaves the cockpit 9 for a predetermined time (for example, about 3 seconds) or longer (the seat switch 32 is turned off), the auto-cruise traveling stops. It is good also as a structure. That is, the control device 100 returns the trunnion shaft 30 to neutral and stops the tractor. An operator may stand up from the cockpit 9 in order to confirm the front and back of the tractor and the work implement, but safety is ensured even in such a case.

  Further, even when the turn-off time by the seat switch 32 is within a predetermined time, when the turn-on / off by the seat switch 32 is frequently detected (for example, when 2 to 3 bounces are made once while traveling 10 m) In this case, it is assumed that the farm scene or road scene is uneven. In such a case, the configuration may be such that auto-cruise traveling stops. Since it is necessary to drive with care on a field or road with severe unevenness, it is safer to stop the auto-cruise travel and make the environment in which the operator can drive with tension.

  In the case of a so-called one-pedal structure of the forward / backward seesaw type in which the forward / backward movement and the speed change operation can be performed only by the accelerator pedal 15 without providing the forward / backward lever 10, a response is made when the pedal is operated from forward to backward or from backward to forward. Delay (loss) is likely to occur. Therefore, when the accelerator pedal 15 has a one-pedal configuration, even if it is set to the insensitive side by the vehicle speed slow response dial 14b, the control device 100 sets the sensitive side during the forward / reverse switching operation to increase the vehicle speed slow response speed. It is better to strengthen the response intentionally.

  In order to allow for an operation delay of the one-pedal configuration with respect to the operation of the forward / reverse lever 10, for example, a sensitive side of about 10% to 15% is desirable from the set value of the vehicle speed slow response dial 14b. The idea is to add alpha to the sensitive side of the currently set value of the vehicle speed slow response dial 14b. With this configuration, it is possible to prevent a delay in response during forward / reverse operation and improve operability.

  The present invention can also be used for other work vehicles that perform auto-cruise traveling.

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 9b Operation panel 10 Forward / reverse lever 10a Forward side solenoid 10b Reverse side solenoid 10c Forward / backward lever position sensor 11 Throttle lever 11a Throttle lever sensor 12 Lever for raising / lowering work implement 12a 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 21 Sub transmission lever 21a Sub transmission lever position sensor 22 Bonnet 23a Mid PTO transmission lever 23b Rear PTO transmission lever 30 Torani Shaft 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 36 rotating shaft 38 meshing transmission 39 auxiliary 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 90 memory 92 timer 100 controller (controller)
DESCRIPTION OF SYMBOLS 101 Increase switch 102 Deceleration switch 103 Engine electronic governor 105 Interlocking off switch 110 Maximum speed holding switch 113 Vehicle speed slowness holding switch 120 Lamp 123 Front sensor 125 Display part 127 Buzzer

Claims (2)

An engine (5) mounted on the traveling vehicle body (1);
It has a trunnion shaft (30) for changing the inclination angle of the swash plate (34d) for inputting the power of the engine (5) and adjusting the hydraulic pressure to be output, and the rotation angle of the trunnion shaft (30) A hydrostatic continuously variable transmission (34) for outputting an output rotational speed based on the corresponding hydraulic pressure;
A trunnion shaft rotation mechanism (34a, 65, etc.) for rotating the trunnion shaft (30);
A sub-transmission (38) that receives the rotational power of the hydrostatic continuously variable transmission (34) to change speed;
A traveling device (2 and / or 3) driven by the output of the auxiliary transmission (38);
An accelerator pedal (15) for adjusting a rotation angle of the trunnion shaft (30) in accordance with a depression amount via a trunnion shaft rotation mechanism (34a, 65, etc.);
An accelerator pedal detection means (15a) for detecting the depression amount of the accelerator pedal (15);
An operation means (14c) for auto cruise traveling for keeping the traveling speed of the traveling device (2 and / or 3) constant;
A switch for speeding up or decelerating during constant speed running by the auto cruise running operating means (14c), the speed increasing switch (101) or the speed reducing switch (102) that is turned on only while being pressed;
When the auto-cruise driving operation means (14c) is operated, the rotation angle of the trunnion shaft (30) corresponding to the depression amount of the accelerator pedal (15) detected by the accelerator pedal detection means (15a) at that time. An auto-cruise function for controlling the trunnion shaft rotation mechanism (34a, 65, etc.) so as to maintain a constant speed of the travel device (2 and / or 3), and a speed increasing switch during the auto-cruise function When the (101) or deceleration switch (102) is pressed within a predetermined time, the trunnion shaft rotating mechanism (34a, 65, etc.) is controlled to temporarily increase the traveling speed at that time. and a temporary accelerated reduction function of speed or deceleration, the speed increasing switch (101) during automatic cruise function or deceleration switch (102) said predetermined time When the pushing operation is performed beyond the above, while the pushing operation is being performed, the trunnion shaft turning mechanism (34a, 65, etc.) is controlled to continuously increase or decrease the traveling speed at that time. a work vehicle characterized by comprising the control device and the <br/> (100) having a deceleration function. When the speed increasing switch (101) or the speed reducing switch (102) is pushed beyond the predetermined time during the auto-cruise function and the operation is released, the control device (100) releases the trunnion shaft rotation. The work vehicle according to claim 1, further comprising an auto-cruise speed changing function for controlling a moving mechanism (34a, 65, etc.) to maintain a constant traveling speed at the time of release .

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