JP2008298099A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working vehicle automatically adjusting a travel speed in an advance and a retreat traveling to enhance working efficiency, while securing safety, even if an advance and a retreat traveling is frequently repeated. <P>SOLUTION: A turning angle of a trunnion shaft 92 is adjusted by a hydraulic cylinder 93 by operation of a main shaft lever 20, and output of a transmission including an HST 34 is made in an advancing direction, a neutral or a retreat direction by an advance-retreat lever 10. A shift position when operating a sub-shift lever 21 to the longest shift position of work time of the last time, is stored in a memory 90a as a memory shift position separate in the advance and the retreat traveling. When the advance-retreat lever 10 is operated to the advance side or the retreat side next time, since a control device 90 shifts the transmission to the memory shift position separately stored in response to the advance and the retreat traveling, a high vehicle speed is produced only by operating the advance-retreat lever 10 to the retreat side particularly in the retreat traveling, and operation labor of an operator is reduced, and at the same time, the working efficiency is also improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a work vehicle such as a tractor for agriculture, construction, transportation, etc. having a transmission comprising a hydrostatic continuously variable transmission and a meshing transmission.

  2. Description of the Related Art Conventionally, in a working vehicle such as a tractor, a movable swash plate of a variable displacement hydraulic pump of a hydrostatic continuously variable transmission (hereinafter sometimes referred to as HST) is linked with a main transmission lever as a transmission system of the main transmission. A transmission system is known in which the output rotational speed is changed by changing the discharge amount from the hydraulic pump by connecting and rotating the main transmission lever.

  Using HST makes it possible to change the speed steplessly, making it easier to obtain the desired travel speed. However, when performing an operation from forward travel to reverse travel or the reverse operation, the stroke of the main shift lever operation is lengthened and operability is improved. It was getting worse. In addition, after working at the set traveling speed, the headland is reached, and it is difficult to reproduce the traveling speed of the work before the turn after repeating forward and backward when turning, etc. Even when switching to, it was difficult to set the running speed.

Therefore, in the traveling vehicle described in Japanese Patent Application Laid-Open No. 2002-250437, means for detecting the rotational position of the main transmission operating tool, means for detecting the rotational position of the forward / reverse switching operating tool, and the movable swash plate of the HST hydraulic pump Means for detecting the tilt angle of the movable swash plate, means for changing the tilt angle of the movable swash plate, each means is connected to the controller, and the operation direction of the forward / reverse switching operation tool and the speed set by the main transmission operation tool are set. By performing control so that the movable swash plate is tilted, for example, when turning around a farm field or when traveling forward and backward repeatedly, it is easy to move forward simply by operating the forward / reverse lever. The traveling and the reverse traveling are switched, and the traveling speed is set to the same speed as before the switching, so that the speed change operation is unnecessary and the maneuverability is improved as compared with the conventional one.
JP 2002-250437 A

  In general, in a work using a traveling vehicle such as a tractor on a headland, work is often performed at a slow vehicle speed in order to improve leveling. For this reason, when the tractor moves backward, the vehicle often backs up several steps faster than the vehicle speed that it has been working on so far in order to reduce the time loss during backward movement. At this time, in the traveling vehicle described in Patent Document 1, it is necessary to change the traveling speed by performing a speed increasing operation after setting the forward / reverse lever to the reverse side, and the operation of the main transmission lever is troublesome.

  Accordingly, an object of the present invention is to provide a traveling vehicle that can automatically adjust the traveling speed during forward and backward travel to increase work efficiency while ensuring safety even when the vehicle is frequently moved forward and backward. It is to be.

The above-mentioned problem of the present invention is solved by the following solution means.
That is, the invention according to claim 1 is a hydrostatic continuously variable transmission (34) having an engine (5) and a trunnion shaft (92) for outputting the power of the engine (5) by adjusting the rotation angle. And a meshing transmission (38) for changing the output of the hydrostatic continuously variable transmission (34) to a plurality of shift stages and outputting the same, and a trunnion of the hydrostatic continuously variable transmission (34) A hydraulic cylinder (93) for turning the trunnion shaft for determining the turning angle of the shaft (92), and a hydrostatic continuously variable transmission by adjusting the turning angle of the trunnion shaft (92) by the hydraulic cylinder for turning the trunnion shaft (93) A forward / reverse lever (10) for outputting the output of (34) in the forward direction, neutral or reverse direction of the vehicle, and a main transmission lever (20) for setting the operation amount of the trunnion shaft turning hydraulic cylinder (93). , The main transmission lever 20), the output of the hydrostatic continuously variable transmission (34) set in 20) is manually selected by selecting a specific shift stage from among a plurality of shift stages that can be set by the meshing transmission (38). The shift lever (21) and a memory (90a) for storing the shift position when the sub-shift lever (21) is operated at the shift position with the longest working time in the previous time as separate memory shift positions during forward and reverse travel And when the forward / reverse lever (10) is operated forward or backward during the next operation, control is performed to shift the transmission to the stored memory shift position separately for forward and backward movements, respectively. A work vehicle provided with a device (90).

  The invention described in claim 2 further includes a memory switch (88) capable of storing a target position of one or more trunnion shafts (92), and the control device (90) operates the main transmission lever (20). The work vehicle according to claim 1, further comprising a configuration for changing the position of the trunnion shaft (92) to a target position stored by the memory switch (88) regardless of the position.

  According to the first aspect of the invention, it is possible to shift to the shift position of the transmission that has the longest previous work time during forward movement and reverse movement, so that the workability is improved as compared with the prior art. ) To the reverse side, the vehicle speed is increased, reducing the operator's operating effort and improving the work efficiency.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, when the memory switch (88) is operated, it can be changed to a desired vehicle speed with one touch.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
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.
Hereinafter, a tractor will be described as an example of a work vehicle. 1 is an overall side view, FIG. 2 is a plan view of the tractor of FIG. 1, FIG. 3 is a power diagram of the transmission of the tractor of FIG. 1, and FIG. 4 is a control block diagram of the transmission.

  The tractor shown in FIGS. 1 and 2 includes front wheels 2 and 2 and rear wheels 3 and 3 in the front and rear portions of the fuselage, and the transmission in the transmission case transmits the rotational power of the engine 5 (FIG. 3) mounted on the front of the fuselage. Thus, the vehicle is decelerated as appropriate, and is transmitted to the front wheels 2, 2 and the rear wheels 3, 3.

  A steering handle 7 is supported on a handle post 6 in the center of the aircraft, and a cockpit 9 is provided behind the steering handle 7. Below the steering handle 7 is provided a forward / reverse lever (sometimes referred to as a linear shift lever) 10 that switches the advancing direction of the airframe to the forward / backward direction. When the forward / reverse lever 10 is moved forward, the aircraft moves forward, and when it is moved backward, it moves backward. An accelerator lever 11 is provided on the opposite side of the forward / reverse lever 10 with the handle post 6 interposed therebetween, and an accelerator pedal 15 and left and right brake pedals 16 and 17 are disposed at the right corner of the step floor 13 to provide a step floor. A clutch pedal 19 is disposed at the left corner portion of 13.

  A main transmission lever 20 that can select a gear position from 1st speed to 8th speed is located in the left front part of the cockpit 9 and a sub transmission lever 21 that can select any one of low speed, medium speed, high speed, and neutral positions. A PTO main transmission lever 23 is provided on the rear side, and further on the rear side thereof, from which 1st to 3rd speeds and a neutral position can be selected. Further, on the right side of the cockpit 9, a position lever 24 for setting the height of a working machine (not shown), an automatic tilling depth lever 25 for automatically setting the tilling depth of the field, and behind these levers 24, 25. Is provided with a right-up switch 27 and a right-down switch 28, followed by an automatic horizontal switch 29 (when turned on, the absolute horizontal position of the tractor (not horizontal to the field scene but horizontal to the earth's horizontal plane)) And the backup switch 30 (the work implement raising link 31 raises the work implement when the forward / reverse lever 10 is in the reverse position). Further, the link 31 for connecting a work machine (not shown) is provided behind the machine body.

  FIG. 3 is a diagram showing a traveling transmission system of a tractor having the hydrostatic continuously variable transmission 34 of the present embodiment. The rotational power of the engine 5 is transmitted to the main clutch 32 that is operated by depressing the pedal-operated clutch pedal 19 and then transmitted from the hydrostatic continuously variable transmission input shaft 33 to the hydrostatic continuously variable transmission 34. . The hydrostatic continuously variable transmission 34 includes a hydraulic closed circuit 34c having a variable displacement hydraulic pump 34a and a constant displacement hydraulic motor 34b, and is introduced from an input shaft 33 of the hydrostatic continuously variable transmission. The hydraulic pump 34a is operated by motive power, 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 34b, and the travel output shaft 36 is supplied by the hydraulic motor 34b. To drive the power to the meshing transmission 38.

  The sub-transmission clutch 39 of the meshing transmission 38 is slidable in the left and right directions in FIG. 39 is transmitted from the auxiliary transmission clutch 39 to the gear 45 of the transmission shaft 43, and the rotation of the transmission shaft 43 is driven through the differential device 46 at the traveling speed of the auxiliary transmission high speed stage.

  Further, when the auxiliary transmission clutch 39 is moved to the right from the position shown in FIG. 3 and the auxiliary transmission clutch 39 is engaged with the gear 45 and the medium speed gear 47 of the transmission shaft 43, the power from the travel output shaft 36 is transmitted to the gear. 41 is transmitted from the gear 49 to the subtransmission clutch 39 through the gear 50, the gear 51, and the gear 47 sequentially, and further transmitted from the subtransmission clutch 39 to the gear 45 of the transmission shaft 43. The movement of the rear wheel 3 is driven at the traveling speed of the intermediate speed stage through the differential device 46.

  When the auxiliary transmission clutch 39 further moves to the right side and engages with the gear 45 and the low speed gear 55 of the transmission shaft 43, the power from the travel output shaft 36 is transferred from the gear 49 to the gear 56 via the gear 41, and further from the gear 56. Is transmitted to the gear 57, transmitted from the gear 55 coaxial with the gear 57 to the auxiliary transmission clutch 39, and further transmitted from the auxiliary transmission clutch 39 to the gear 45 of the transmission shaft 43, and the rotation of the transmission shaft 43 is transmitted via the differential device 46. The rear wheel 3 is driven at the traveling speed of the sub-speed stage.

  Even if the sliding position of the auxiliary transmission clutch 39 is on the left or right side, the output from the transmission shaft 43 is transmitted to the front wheel output shaft 61 via the gears 53, 59, 60, etc. in order. At this time, if the hydraulic clutch 63 is connected, the front wheel 2 is driven together with the rear wheel 3 via the differential device 65, and if the hydraulic clutch 64 is connected, the front wheel speed is increased. It becomes. The hydraulic clutch 63 and the hydraulic clutch 64 are not connected at the same time, and if the hydraulic clutch 63 and the hydraulic clutch 64 are not connected together, only the rear wheel 3 is driven.

  On the other hand, the power input from the hydrostatic continuously variable transmission input shaft 33 to the variable displacement hydraulic pump 34a is transmitted from the pump output shaft 66 to the PTO drive system. The PTO drive system includes a PTO forward / reverse clutch 67 and a PTO auxiliary transmission clutch 68. When the tractor travels on the road, either one or both of the clutches 67 and 68 are in an unconnected state to drive the work machine. The PTO drive system is not driven.

  When working with the work implement in the field, the accelerator lever 11 is pulled toward the operator side (front side) and the engine speed is set to the rated speed, or a constant speed from the rated speed to the maximum speed. The hydraulic continuously variable transmission input shaft 33 and the pump output shaft 66 rotate at a constant rotation speed. The state shown in FIG. 3 is a neutral state, and the PTO shaft 69 directly connected to the pump output shaft 66 rotates together.

  When the PTO forward / reverse clutch 67 is slid in the left direction in the figure, the PTO forward / reverse clutch 67 meshes with the gear 70 and the gear 71 of the PTO shaft 69, so that the power of the PTO shaft 69 is the gear 70, the PTO forward / reverse clutch 67, and the gear 71. , The PTO transmission shaft 75 is driven through the gear 71a, the gear 72, the gear 74, the gear 78, the gear 77, and the gear 76 sequentially (PTO reverse rotation). When the PTO forward / reverse clutch 67 is slid in the right direction in the figure, the power of the PTO shaft 69 drives the PTO transmission shaft 75 through the gear 70, the PTO forward / reverse clutch 67, the gear 73, the gear 77, and the gear 76 sequentially. (PTO normal rotation).

  The power from the gear 78 interlocking with the driving of the gear 74 integrated with the gear 72 is also transmitted to the PTO transmission shaft 75, and when the PTO auxiliary transmission clutch 68 is in the position moved to the left most from the illustrated position, the gear 79 and the gear The gear dock 81 is engaged with the gear dock 83 provided in the PTO auxiliary transmission clutch 68 via 80, and the PTO first speed is obtained by the PTO drive shaft 84. When the PTO auxiliary transmission clutch 68 moves left or right from the illustrated position, power is transmitted to the PTO auxiliary transmission low speed gear 85 or the PTO auxiliary transmission high speed gear 86 that meshes in each case, and the gear 85, gear 68a. When the power is sequentially transmitted to the PTO drive shaft 84, the PTO second speed is obtained, and when the power is sequentially transmitted to the gear 86, the gear 68b and the PTO drive shaft 84, the PTO third speed is obtained.

  The tractor having the above-described configuration depresses the clutch pedal 19 when traveling on the road, and sets the auxiliary transmission lever 21 to a position suitable for traveling on the road (basically, the high-speed position may be set to the medium-speed position or the low-speed position). Next, the main transmission lever 20 is moved to an arbitrary position. The main speed change lever 20 can be selected from a minimum speed of 1st speed to a maximum speed of 8th speed, but the basic speed when traveling on the road is 8th speed.

  Next, the forward / reverse lever 10 is moved forward or backward, and the engine pedal is increased by stepping on the accelerator pedal 15 while slowly releasing the clutch pedal 19 (with the main clutch 32 connected). At this time, even if the accelerator pedal 15 is fully depressed, the maximum speed is restricted to the position of the maximum speed stage (8th speed) of the main transmission lever 20.

  Further, when working in the field, after depressing the clutch pedal 19, the sub-shift lever 21 is set to an appropriate position (basic is a low speed or medium speed position). Next, the main transmission lever 20 is moved to an arbitrary position (selectable from the first speed to the eighth speed according to the type of work), and the forward / reverse lever 10 is moved to the forward position. The accelerator lever 11 is moved to the pilot side (front side), and the engine speed is set to a rated speed or a maximum speed greater than the rated speed. Next, the clutch pedal 19 is moved forward (with the main clutch 32 connected). At this time, the engine speed is set between the rated speed and the maximum speed equal to or higher than the rated speed, but the working speed is restricted by the position of the main transmission lever 20.

  As described above, the accelerator pedal 15 is used instead of the accelerator pedal 15 when the work implement is used in the field. Further, when traveling on the road, the accelerator pedal 15 is used and the accelerator lever 11 is not used. When driving on the road, the accelerator pedal 15 can be operated in the same way as when driving a car, and the engine rotation must be kept constant when working in the field. . Therefore, the accelerator lever 11 is operated during the work, and even if the hand is released from the accelerator lever 11 during the work, it does not return to the original position. Therefore, it is possible to maintain a constant engine speed by maintaining the operated accelerator position.

  FIG. 5 shows a left side view of the handle post 6, the airframe near the cockpit 9, and the main speed change lever 20 alone. FIG. 6 is an enlarged view of the vicinity of the base portion of the main transmission lever 20. The main speed change lever 20 can change the speed stage from 1st to 8th speed, and a position sensor 20 a capable of detecting a position position corresponding to each speed stage is provided at the base of the lever 20. The detection value of the position sensor 20a is output to the controller 90 (FIG. 4).

  7 and 8 are plan views of the transmission case 91 (FIGS. 7A and 8A) and a plan view of the hydrostatic continuously variable transmission 34 housed in the transmission case 91. FIG. The figure (FIG.7 (b), FIG.8 (b)) is shown. FIG. 9 is a side view of the transmission case 91 as viewed from the direction of arrow A in FIG. As shown in FIGS. 5 to 9, a link mechanism 95 that connects the hydraulic cylinder 93 that rotates the trunnion shaft 92 of the hydrostatic continuously variable transmission 34 and the trunnion shaft 92 that protrudes outside the transmission case 91 is provided. It is attached to the outer wall portion of the transmission case 91.

  The other end of the arm 95a having one end rotatably connected to the tip of the piston rod 93a of the hydraulic cylinder 93 is rotatably supported on the outer wall of the transmission case 91, and further to the other end of the arm 95a. One end of a rod 95b provided in a direction perpendicular to the longitudinal direction of the arm 95a is rotatably provided, and the other end of the rod 95b is substantially parallel to the arm 95a through a rotatable arm 95c. The end of the rod 95d, the length of which can be adjusted in any direction, is pivotally connected. The other end of the rod 95d whose length can be adjusted is rotatably connected to one end of a short arm 95e, and a boss 95f is fixed to the other end of the short arm 95e.

  The boss 95f is fixed to the shaft 95q with a bolt 95p. The shaft 95q is rotatably supported with respect to the transmission case 91, and a plate 95g is fixed to one end of the shaft 95q. The other end of the plate 95g is rotatably connected to a link arm 95h via a pin 95r, and the link arm 95h is rotatably connected to a cam 95j integrated with the trunnion shaft 92. Here, the cam 95j is fixed to the boss 95s, and the boss 95s is fixed to the trunnion shaft 92 by a bolt 95t.

  The plate 95g and the link arm 95h are connected by a pin 95r, and the connecting portion by the pin 95r has an arc-shaped elongated hole 95k1 of a fan-like member 95k fixed to the transmission case 91 with a shaft 95q as a pivot. Since the pin 95r is slidable only in the long hole 95k1, the rotation range of the cam 95j is also restricted within the range interlocked with the sliding of the pin 95r.

  By the link mechanism 95, the operation of the hydraulic cylinder 93 is interlocked with the arm 95a, the rod 95d, etc., and the cam 95j rotates together with the trunnion shaft 92. Further, the cam 95j is rotated by the hydraulic cylinder 93 while the side surface of the cam 95j is in contact with the side surface of the roller 95m supported by the transmission case 91.

  The state shown in FIG. 7 shows a state in which the trunnion shaft 92 faces the swash plate 34d of the hydraulic pump 34a of the hydrostatic continuously variable transmission 34 toward the vehicle forward side, and is a plan view of the transmission case 91 of FIG. FIG. 8A) and a plan view of the hydrostatic continuously variable transmission 34 housed in the transmission case 91 (FIG. 8B) show the hydraulic pressure of the hydrostatic continuously variable transmission 34. The state where the swash plate 34d of the pump 34a is directed to the neutral position is shown, and the position where the roller 95m fits into the recess 95j1 of the cam 95j is the neutral position of the trunnion shaft 92. The roller 95m is pressed by a spring from the x direction in FIG. 10 shows a plan view of the transmission case 91 (FIG. 10A) and a plan view of the hydrostatic continuously variable transmission 34 housed in the transmission case 91 (FIG. 10B). The state shows a state in which the swash plate 34d of the hydraulic pump 34a of the hydrostatic continuously variable transmission 34 is disposed facing backward.

  FIG. 11 is a diagram showing the arrangement of shift switches 10a and 10b provided at the base of the forward / reverse lever 10 and the operation mode thereof. 11 (a) and 11 (c) are layout diagrams in which the forward shift switch 10a and the reverse shift switch 10b provided at the base of the forward / reverse lever 10 operate when the forward / reverse lever 10 is in the forward position and the reverse position. FIG. 11B shows a layout when the forward / reverse lever 10 is in the neutral position and does not come into contact with either the forward shift switch 10a or the reverse shift switch 10b.

  When the forward / reverse lever 10 is tilted forward from the neutral position so that the forward shift switch 10a of the forward / reverse lever 10 is operated, it is ready to move in the forward direction, and the reverse shift switch 10b of the forward / reverse lever 10 is operated. When the forward / reverse lever 10 is tilted backward from the neutral position, it is ready to move in the reverse direction. It should be noted that acceleration in the forward and reverse directions of the vehicle is only performed by the main speed change lever 20.

  Further, since an EEPROM 90a for storing the detection value of the position sensor 20a of the main transmission lever 20 shown in FIG. 5 is arranged in the controller 90, first, the position sensor 20a corresponding to the current position of the main transmission lever 20 is arranged. The output value (T), the value (A) of the minimum vehicle speed instruction position of the position sensor 20a, and the value (B) of the maximum vehicle speed instruction position are stored in the EEPROM 90a.

Next, the controller 90 calculates the first value as an output ratio to the hydraulic cylinder 93 with respect to the total stroke amount of the trunnion shaft turning hydraulic cylinder 93 corresponding to the turning angle of the trunnion shaft 92 by the following equation (1). .
Output ratio to hydraulic cylinder = (TA) / (AB) (1)

  In this way, the hydraulic cylinder 93 is operated according to the first value obtained by the above equation (1). The magnitude of the detected value of the trunnion shaft position sensor 92a obtained at that time is the same as that of the trunnion shaft position sensor 92a. Corresponding to a detection range, for example, any voltage value between 0 and 5 volts. Therefore, the detection value of the trunnion axis position sensor 92a is transmitted to the controller 90, and the controller 90 obtains the magnitude of the detection value of the trunnion axis position sensor 92a as a ratio to the magnitude of the entire detection range of the trunnion axis position sensor 92a. This is the second value. The controller 90 controls the obtained second value to be equal to the first value, and when the first value and the second value are equal, the electromagnetic valve (not shown) of the trunnion shaft rotating hydraulic cylinder 93 is shown. (The oil in the cylinder 93 does not leak out and the cylinder piston is held at the position where the output is stopped).

  In general, variations due to errors in assembling the link mechanism 95 that correlates variations in the mounting position of the position sensor 20a of the main transmission lever 20 and the rotation angle of the trunnion shaft 92 of the hydrostatic continuously variable transmission 34 are different for each work vehicle. is there.

However, according to the present embodiment, the rotation angle of the trunnion shaft 92 determined according to the operation amount of the trunnion shaft rotation hydraulic cylinder 93 and the operation amount of the trunnion shaft rotation hydraulic cylinder 93 determined according to the operation amount of the main transmission lever 20. Even if a variation due to an assembling error of a related member or the like occurs in this relationship, this variation can be absorbed. By implementing this for all work vehicles, a highly accurate travel control device can be obtained.
However, if the signal from the trunnion shaft position sensor 92a does not reach the value calculated by the equation (1) even after a predetermined time has elapsed, the output to the hydraulic cylinder 93 is stopped and an alarm is issued.

  A position sensor 92a (FIG. 7) for detecting the rotation position of the trunnion shaft 92 by the operation of the trunnion shaft rotation hydraulic cylinder 93 is configured to detect the degree of rotation of the rotation shaft 93d. The position sensor 92a is connected to the other end of an arm 93c having one end rotatably provided on the opposite side of the rod 95d from the connecting portion of the arm 95e. Thereby, the position sensor 92a detects the movement (position) of the trunnion shaft 92. The position sensor 92a of the trunnion shaft 92 includes a stopper 93e provided at the maximum extension setting position on the forward side of the piston rod 93a of the trunnion shaft rotating hydraulic cylinder 93 and a stopper 93f (FIG. 9) provided at the minimum shortening setting position on the reverse side. Each set position is set as a reference value that allows the trunnion shaft 92 to rotate. The position where the roller 95m fits into the recess 95j1 of the cam 95j is the neutral position of the trunnion shaft 92, which is also a reference value. Each set position detected by the position sensor 92a is stored in a memory (EEPROM) 90a of the controller 90 as a reference position.

  Further, the detection of the trunnion shaft position sensor 92a contacting the stopper 93e provided at the maximum extension setting position on the forward side of the piston rod 93a of the hydraulic cylinder 93 for turning the trunnion shaft and the stopper 93f provided at the minimum shortening setting position on the reverse side. Since the rotation range of the trunnion shaft rotation hydraulic cylinder 93 can be controlled using the position as a reference position, the dimensions of the link mechanism 95 for associating the rotation angle of the trunnion shaft 92 of the hydrostatic continuously variable transmission 34 can be controlled. Errors and the like can be absorbed.

  Further, the hydraulic cylinder 93 is expanded and contracted according to the state of the main transmission lever position sensor 20a and the forward / reverse lever shift switches 10a and 10b, and the vehicle is moved forward and backward, but the throttle sensor 11a (see FIG. ) To change the operating speed (by changing the pulse on time) of the trunnion shaft rotating hydraulic cylinder 93 according to the position of the throttle sensor 11a.

  In general, in pillow work, etc., work is often performed at a slow vehicle speed in order to improve leveling. For this reason, when going backwards, in order to reduce the loss of work time, the vehicle is often backed by several steps faster than the vehicle speed that has been worked until then. At this time, when the linear shift lever (forward / reverse lever) 10 is set to the reverse side, conventionally, it is necessary to change the vehicle speed to the reverse speed increasing operation, and this operation sometimes feels troublesome.

  Therefore, in this embodiment, the shift position when the auxiliary shift lever 21 is operated is stored in the shift position where the previous work time is the longest in the memory (EEPROM) 90a of the controller 90, but the shift position is advanced. When the sub-shift lever 21 is operated to the forward side or the reverse side during the next work, the memory shift position is automatically set corresponding to the forward and reverse directions, respectively. The speed was changed.

At this time, the memory shift position stored on the reverse side is set so as to prohibit the sub-speed “high speed” stage, or the shift position up to the second speed is limited to the previous memory shift position on the forward side. With this configuration, the vehicle speed at the “high speed” stage of the sub-shift is prevented from becoming much faster than the vehicle speed at the time of forward movement.
A flowchart of the above control is shown in FIG.
Thus, particularly when the vehicle is traveling backward, only by operating the forward / reverse lever 10 to the reverse side, the vehicle speed is increased, and the operator's operation labor is reduced and the work efficiency is improved.

  In addition, a memory switch 88 capable of storing at least one target position of the trunnion shaft 92 is provided in the handle portion of the main transmission lever 20 (see FIG. 5), and the main transmission lever 20 is in any position regardless of the position. When the memory switch 88 is operated, the target position of the trunnion shaft 92 calculated by the operation position of the main transmission lever 20 is ignored, and the target position of the trunnion shaft 92 stored in the memory switch 88 is changed. . A flow chart of control using the memory switch 88 is shown in FIG. With this control configuration, when the memory switch 88 is operated, it can be changed to a desired vehicle speed with one touch.

The memory switch 88 is a rebound momentary switch (a function that works when pressed, and a switch that returns to its original position when released). By holding down the switch 88 for 2 seconds or longer, the target position of the trunnion shaft 92 calculated based on the position of the main transmission lever 20 at that time is stored in the EEPROM 90a as a memory trunnion position. A flowchart of control using the momentary switch is shown in FIG.
When this momentary switch is used, the stored value of the target position of the trunnion shaft 92 can be easily changed. Further, by using a rebound type momentary switch, the stored value can be changed with the same switch, and the cost can be reduced.

  Further, as shown in the flowchart of FIG. 15, the trunnion shaft calculated by the position of the main transmission lever 20 by operating the main transmission lever 20 with the target position of the trunnion shaft 92 changed by operating the memory switch 88. When the target position of the trunnion shaft 92 set by the memory switch 88 matches the target position of the 92, the control of the target position of the trunnion shaft 92 by the memory switch 88 is released, and the calculation is performed at the operation position of the main transmission lever 20. The trunnion shaft 92 is controlled to be positioned at the trunnion target position.

  The fact that the main transmission lever 20 is operated means that the operator wants to change the vehicle speed, and the position of the trunnion shaft 92 corresponding to the operation of the main transmission lever 20 and the target position of the trunnion shaft 92 set by the memory switch 88 match. After that, by releasing the control of the target position of the trunnion shaft 92 by the memory switch 88, the vehicle speed according to the main transmission lever 20 is obtained, and the traveling speed control without a sense of incongruity becomes possible.

  Further, as shown in the flowchart of FIG. 16, when the memory switch 88 is operated, the target position of the trunnion shaft 92 calculated based on the operation position of the main transmission lever 20 is ignored and stored in the memory switch 88. The configuration for changing to the target position of the trunnion shaft 92 can be stored separately for each set speed stage of the sub-shift lever 21, so that a plurality of memory positions can be stored if different sub-shifts are used. Thus, the application range is widened.

  However, when the sub gear is set to the “high speed” position, the memory range is restricted to 1 to 5 speeds, and if 6 to 8 speeds are selected, the running speed becomes too fast. By making the setting of the steps impossible, traveling safety can be ensured.

  In addition, as shown in the flowchart of FIG. 17, when the target position of the trunnion shaft 92 is changed by operating the memory switch 88 (operable when the forward / reverse lever 10 is neutral; otherwise, it cannot be operated). Is slower than normal (when the main speed change lever 20 is operated to change the vehicle speed), and the operating speed of the trunnion shaft turning hydraulic cylinder 93 is made slower to change to the target position of the trunnion shaft 92 set by the memory switch 88. .

The change control of the target position of the trunnion shaft 92 is for the following reason.
That is, when the main speed change lever 20 is operated to change the vehicle speed, the vehicle speed is changed according to the position to which the main speed change lever 20 is changed, so that the operator knows how much the vehicle speed changes. However, when changing the vehicle speed with the memory switch 88, for example, if you forget the setting position of the trunnion shaft 92 by the previous memory switch 88, you do not know how much the vehicle speed will be changed, rather than the operator thinks If the vehicle speed is significantly changed, there is a risk of being surprised. Therefore, when the vehicle speed is changed by the memory switch 88, the rotation speed of the trunnion shaft 92 is made slower than when the main speed change lever 20 is operated to change the vehicle speed, and the target position of the trunnion shaft 92 is changed slowly. To ensure safety.

  Further, as shown in the perspective view of the lever guide 108 in FIG. 18, a “road” position is provided in addition to the normal “low speed”, “medium speed”, and “high speed” as the setting region of the auxiliary transmission lever 21. If the entire rotation position of the trunnion shaft 92 can be stored in the “on the road” position, it can be used in an auto-cruise at the “on the road” position as shown in the flowchart of FIG. At this time, when the brake is depressed, the target position of the trunnion shaft 92 is set to the neutral position while the brake is depressed, and when the brake operation is released, the target position of the trunnion shaft 92 is set to the lowest speed “1st speed”. Change to position.

  With the above configuration, it becomes possible to stop the traveling vehicle only by the brake operation, and after that, after the vehicle starts running by releasing the brake, the auto cruise traveling can be performed again by operating the memory switch 88, which is very easy to use. Become a thing. In addition, the load on the HST 34 (moving forward while applying the brake) is reduced, leading to a longer life of the HST 34.

  As shown in the flowchart of FIG. 20, in the tractor of the present embodiment, if the manually operated auxiliary transmission lever 21 is in the neutral state, the trunnion shaft 92 is positioned at the neutral position even if the accelerator pedal 15 is depressed. The configuration.

  Normally, when the sub-shift lever 21 is operated, a shifter is actuated by the sub-shift (electromagnetic) clutch 39 to change the gear position to a shift position corresponding to the operation position of the sub-shift lever 21. Normally, when the sub-shift lever 21 is set to a position other than neutral and the forward / reverse lever 10 is operated to the forward side or reverse side other than neutral, the trunnion shaft 92 rotates according to the operation position of the main shift lever 20 and the accelerator pedal 15 is depressed. If the operation position of the main transmission lever 20 is, for example, the fifth speed, the vehicle travels at the fifth speed.

  However, the sub-transmission (electromagnetic) clutch 39 breaks down, and the gear of the sub-transmission device remains in the original shift position without changing the gear to the shift position corresponding to the operation position of the sub-transmission lever 21. If the operator puts the auxiliary transmission lever 21 into the neutral position, the vehicle can be safely stopped by positioning the trunnion shaft 92 at the neutral position.

  Furthermore, when the trunnion shaft 92 is driven to the vicinity of the maximum forward position, but the vehicle speed does not exceed 80% of the theoretical vehicle speed, the operator is instructed to adjust the maximum forward position reference value of the trunnion shaft 92. Therefore, the meter panel 8 (see FIG. 2) displays the fact.

  If the sensor reference value has not been adjusted for many years, the vehicle speed that should theoretically be achieved will not be obtained even if the trunnion shaft is positioned up to the maximum forward position reference value of the trunnion shaft 92 due to a slight deviation of the trunnion shaft position sensor 92a. In addition, you will feel that you are slow on the road.

  Therefore, as described above, it is possible to automatically determine that the sensor reference value has shifted and notify the operator via the meter panel 8 so that the vehicle performance can be fully utilized. FIG. 21 shows a flowchart for that purpose. Here, the theoretical vehicle speed is 9 km / h for the L1 speed, 14 km / h for the L2 speed, 25 km / h for the H1 speed, and 40 km / h for the H2 speed.

  The present invention can be used as a travel control device for work vehicles such as tractors for agriculture, construction, and transportation.

It is a left view of the tractor of one Example of this invention. It is a top view of the tractor of FIG. It is a power diagram of the transmission of the tractor of FIG. It is a control block diagram of the transmission of the tractor of FIG. FIG. 2 is a left side view of only the handle post, the fuselage in the vicinity of the cockpit, and the main transmission lever of the tractor of FIG. 1. FIG. 5 is an enlarged view of a base portion of the main transmission lever of FIG. 4. FIG. 7 is a plan view of the transmission case when the tractor of FIG. 1 is moving forward (FIG. 7A) and a plan view of the hydrostatic continuously variable transmission housed in the transmission case (FIG. 7B). is there. FIG. 8B is a plan view of the transmission case in the neutral state of the tractor of FIG. 1 (FIG. 8A) and a plan view of the hydrostatic continuously variable transmission housed in the transmission case (FIG. 8B). is there. It is the side view of the transmission case seen from the arrow A direction of Fig.8 (a). FIG. 10A is a plan view of the transmission case when the tractor of FIG. 1 is traveling backward (FIG. 10A), and FIG. 10B is a plan view of the hydrostatic continuously variable transmission housed in the transmission case (FIG. 10B). is there. 1 when the forward / reverse lever (linear shift lever) of the tractor in FIG. 1 is in the forward position (FIG. 11 (a)), the neutral position (FIG. 11 (b)) and the reverse position (FIG. 11 (c)). It is a figure which shows arrangement | positioning of the shift switch provided in the base part, and its operation | movement aspect. It is a flowchart of control of one Example of this invention. It is a flowchart of control of one Example of this invention. It is a flowchart of control of one Example of this invention. It is a flowchart of control of one Example of this invention. It is a flowchart of control of one Example of this invention. It is a flowchart of control of one Example of this invention. It is a perspective view of the lever guide of one Example of this invention. It is a flowchart of control of one Example of this invention. It is a flowchart of control of one Example of this invention. It is a flowchart of control of one Example of this invention.

Explanation of symbols

2 Front wheel 3 Rear wheel 5 Engine 6 Handle post 7 Steering handle 8 Meter panel 9 Control seat 10 Forward / reverse lever 10a, 10b Shift switch 10c Grip part 11 Accelerator lever 11a Throttle sensor 13 Step floor 15 Accelerator pedal 16, 17 Brake pedal 19 Clutch Pedal 20 Main transmission lever 20a Position sensor 20b Grip part 21 Sub-transmission lever 23 PTO main transmission lever 24 Position lever 25 Automatic tilling lever 27 Right-up switch 28 Right-down switch 29 Automatic horizontal switch 30 Backup switch 31 Work equipment raising link 32 Main clutch 33 Hydrostatic continuously variable transmission input shaft 34 Hydrostatic continuously variable transmission 34a Hydraulic pump 34b Hydraulic motor 34c Hydraulic closed circuit 34d Swash plate 36 Traveling Force shaft 38 Meshing transmission 39 Sub-transmission clutch 41 Gear 42 High-speed gear 43 Transmission shaft 45 Gear 46 Differential device 47 Medium-speed gear 49, 50, 51, 53 Gear 55 Low-speed gear 56, 57, 59, 60 Gear 61 Front wheel output shaft 63 Hydraulic clutch 64 Hydraulic clutch 65 Differential device 66 Pump output shaft 67 PTO forward / reverse clutch 68 PTO auxiliary transmission clutch 68a, 68b Gear 69 PTO shaft 70, 71, 71a, 72, 73, 74 Gear 75 PTO transmission shaft 76 , 77, 78, 79, 80 Gear 81, 83 Gear dock 84 PTO drive shaft 85 PTO sub-speed low speed gear 86 PTO sub-speed high speed gear 88 Memory switch 90 Controller 90a EEPROM 91 Transmission case 92 Trunnion shaft 92a Position sensor 93 Trunnion Hydraulic shaft for shaft rotation Linda 93a Piston rod 93c Arm 93d Rotating shaft 93e, 93f Stopper 95 Link mechanism 95a Arm 95b Rod 95c Arm 95d Rod 95e Short arm 95f Boss 95g Plate 95h Link arm 95j Cam 95j1 Recessed 95k Fan-like member 95k1 Long hole 95m 95q Roller 95p Shaft 95r Pin 95s Boss 95t Bolt 108 Lever guide

Claims (2)

An engine (5),
A hydrostatic continuously variable transmission (34) having a trunnion shaft (92) for outputting the power of the engine (5) by adjusting the rotation angle, and a plurality of outputs of the hydrostatic continuously variable transmission (34). A transmission including a meshing transmission (38) that outputs the gear by changing to the following gear;
A trunnion shaft turning hydraulic cylinder (93) for determining a turning angle of the trunnion shaft (92) of the hydrostatic continuously variable transmission (34);
Front and rear to output the output of the hydrostatic continuously variable transmission (34) in the forward, neutral or reverse direction of the vehicle by adjusting the rotation angle of the trunnion shaft (92) by the hydraulic cylinder (93) for rotating the trunnion shaft Advance lever (10);
A main speed change lever (20) for setting an operation amount of the trunnion shaft turning hydraulic cylinder (93);
By selecting a specific shift stage from among a plurality of shift stages that can be set by the meshing transmission (38), the output of the hydrostatic continuously variable transmission (34) set by the main transmission lever (20) An auxiliary transmission lever (21) set manually,
A memory (90a) for storing the shift position when the auxiliary shift lever (21) is operated at the shift position having the longest work time in the previous time as separate memory shift positions at the time of forward movement and reverse movement;
When the forward / reverse lever (10) is operated forward or backward during the next work, a control device (90 for shifting the transmission to the stored memory shift position separately corresponding to forward and reverse movements, respectively. ) And a work vehicle. Furthermore, a memory switch (88) capable of storing a target position of one or more trunnion shafts (92) is provided,
The control device (90) is configured to change the position of the trunnion shaft (92) to the target position stored in the memory switch (88) regardless of the operation position of the main transmission lever (20). The work vehicle according to claim 1.

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